HVO Kilauea Status

Recent Kilauea Status Reports, Updates, and Information Releases

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Tuesday, September 16, 2014 9:19 AM HST (Tuesday, September 16, 2014 19:19 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Slight deflation occurred over the past day, with minor fluctuations in lava level. At the middle East Rift Zone, the front of the June 27th flow is advancing through forest in Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. An HVO overflight yesterday afternoon confirmed that the flow front has entered the northwest portion of Kaohe Homesteads. The flow was moving through a vacant, forested portion of the subdivision. The flow front had advanced at an average rate of 215 m/day (705 ft/day) between Sep 12 and 15, which is slightly lower than the rate between Sep 10 and 12 (which was 250 m/day, or 820 ft/day). The flow front yesterday afternoon was 15.5 km (9.6 miles) from the vent, measured in a straight line. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) was 17.7 km (11.0 miles). The flow front yesterday afternoon was 3.3 km (2.1 miles) upslope from Apa`a Road. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

A Civil Defense overflight this morning showed continued slow advancement of the flow front in a northeast direction, with continued burning of vegetation.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was slight deflationary tilt at Puʻu ʻŌʻō over the past day, and gradual deflationary tilt has been recorded for more than a week. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views yesterday found a small lava pond in the south pit. The northeast pit, which has hosted a lava pond for several months, was crusted over with only a small incandescent opening and minor spattering. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Slight deflationary tilt began yesterday morning at Kīlauea's summit, ending nearly a week of gradual inflationary tilt. The lava lake level fluctuated with spattering and was roughly 50 m (164 ft) below the Overlook crater rim. There was no major change in seismicity on Kilauea over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HVO/USGS Volcanic Activity Notice

Volcano: Kilauea (VNUM #332010)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE

Issued: Monday, September 15, 2014, 5:15 PM HST (20140916/0315Z)
Source: Hawaiian Volcano Observatory
Notice Number: 2014/H5
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: HI Hawaii and Pacific Ocean

Volcanic Activity Summary: Between September 12 and 15, the June 27th flow widened and advanced north-northeastward at an average rate of 215 m/day (705 ft/day). By the afternoon of September 15, the flow had advanced approximately 15.5 km (9.6 mi) straight-line distance from the vent and 280 m (920 ft) inside the vacant, forested northwest portion of Kaohe Homesteads. At the average rate of advancement of 215 m/day (705 ft/day) since September 12, we project that lava could flow from its current location to Apa`a Rd in 15 days and to the Pāhoa Village Road (government road) in Pāhoa within 20 days. These estimates will be continually refined as we track this lava flow.

Kaohe Homesteads is located between the Wao Kele o Puna Forest Reserve and the town of Pāhoa in the Puna District of the County of Hawai`i.


Recent Observations:
[Lava flow] Lava flow continued to advance north-northeast and has slowed since September 12 to a rate of 215 m/day (705 ft/day).

Hazard Analysis:
[Lava flow] Lava flow from Pu‘u ‘Ō‘ō vent is within the vacant, forested northwest corner of Kaohe Homesteads and could reach the Pāhoa Village Road (government road) in Pāhoa within 20 days.

Remarks: The Pu‘u ‘Ō‘ō vent in the East Rift Zone of Kīlauea Volcano began erupting on January 3, 1983, and has continued erupting for more than 31 years, with the majority of lava flows advancing to the south. Over the past two years, lava flows have issued from the vent toward the northeast. The June 27th flow is the most recent of these flows and the first to threaten a residential area since 2010-2011. On June 27, 2014, new vents opened on the northeast flank of the Pu‘u ‘Ō‘ō cone and fed a narrow lava flow to the east-northeast. On August 18, the flow entered a ground crack, traveled underground for several days, then resurfaced to form a small lava pad. This sequence was repeated three more times over the following days with lava entering and filling other cracks before reappearing at the surface, in two of the cases farther downslope. Lava emerged from the last crack on September 6, forming a surface flow that initially moved to the north, then to the northeast, at a rate of 400 m/day (1,300 ft/day). The flow slowed thereafter and, since September 12, the rate of advancement has been 215 m/day (705 ft/day).

Contacts: HVO media contact
askHVO@usgs.gov

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While this VAN is in effect, regularly scheduled updates are posted at http://hvo.wr.usgs.gov/activity/kilaueastatus.php

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Monday, September 15, 2014 8:54 AM HST (Monday, September 15, 2014 18:54 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation continued, with only slight fluctuations in lava level. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. A Civil Defense overflight this morning observed that the flow front was moving in a northeast direction once again, which is a slight shift from the north direction observed yesterday. They estimated that the flow had traveled 230 m (250 yards) over the past day. The flow front remains close to the boundary of the Wao Kele o Puna forest reserve and Kaohe Homesteads. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

The most recent HVO overflight was Friday afternoon. The flow front at that time was 14.9 km (9.3 miles) from the vent, measured in a straight line, and 170 m (0.1 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) was 17.1 km (10.6 miles). Between September 10 and 12 the advance rate was approximately 250 meters (270 yards) per day.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was slight deflationary tilt at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views this week have found small lava ponds within the northeast, north, south and southeast pits. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Inflationary tilt continued at Kīlauea's summit. The lava lake level fluctuated with spattering and was roughly 50 m (164 ft) below the Overlook crater rim. There was no major change in seismicity on Kilauea over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Sunday, September 14, 2014 9:52 AM HST (Sunday, September 14, 2014 19:52 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation continued, with only slight fluctuations in lava level. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. A Civil Defense overflight this morning observed that the flow front was moving in a more northward direction over the past day, which is a slight shift from its previous northeast direction. The flow had traveled roughly 270 m (300 yards) since Friday, suggesting that the flow advance rate may have slowed over the past several days. The flow front remains close to the boundary of the Wao Kele o Puna forest reserve and Kaohe Homesteads. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

The most recent HVO overflight was Friday afternoon. The flow front at that time was 14.9 km (9.3 miles) from the vent, measured in a straight line, and 170 m (0.1 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) was 17.1 km (10.6 miles). Between September 10 and 12 the advance rate was approximately 250 meters (270 yards) per day.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was slight deflationary tilt at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views this week have found small lava ponds within the northeast, north, south and southeast pits. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Inflationary tilt continued at Kīlauea's summit. The lava lake level fluctuated with spattering and was roughly 50 m (164 ft) below the Overlook crater rim. There was no major change in seismicity on Kilauea over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Saturday, September 13, 2014 9:32 AM HST (Saturday, September 13, 2014 19:32 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation continued, with only slight fluctuations in lava level. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. An HVO overflight yesterday at 12:30 pm showed the flow front was still moving in a general northeast direction, bringing it closer to the western boundary of Kaohe Homesteads (which is the eastern boundary of the Wao Kele o Puna forest reserve). The flow front at that time was 14.9 km (9.3 miles) from the vent, measured in a straight line, and 170 m (0.1 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 17.1 km (10.6 miles). Between September 6 and 10, the flow front advanced at approximately 400 meters (460 yards) per day. Between September 10 and 12 the advance rate dropped to approximately 250 meters (270 yards) per day. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was slight deflationary tilt at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views yesterday found small lava ponds within the northeast, north, south and southeast pits. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Inflationary tilt continued at Kīlauea's summit, but at a slower rate over the past day. The lava lake level fluctuated with spattering and was roughly 50-55 m (164-180 ft) below the Overlook crater rim. The cluster of small earthquakes in the upper East Rift Zone continued over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HVO/USGS Volcanic Activity Notice

Volcano: Kilauea (VNUM #332010)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE

Issued: Friday, September 12, 2014, 8:03 PM HST (20140913/0603Z)
Source: Hawaiian Volcano Observatory
Notice Number: 2014/H4
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: HI Hawaii and Pacific Ocean

Volcanic Activity Summary: Between September 10 and 12, the June 27th flow advanced north-northeastward at an average rate of 250 m/day (820 ft/day). By the afternoon of September 12, the flow had advanced approximately 14.9 km (9.3 miles) straight-line distance from the vent, or to within 170 m (560 ft) of the boundary between the Wao Kele o Puna Forest Reserve and the northwest corner of Kaohe Homesteads. At the average rate of advancement of 250 m/day (820 ft/day) since September 10, we project that lava could flow from its current location into the northwest part of Kaohe Homesteads within a day, and to the Pāhoa Village Road (government road) in Pāhoa within 20 days, if lava is not further confined within the cracks and down-dropped blocks within the East Rift Zone of Kīlauea volcano. These estimates will be continually refined as we track this lava flow.

Kaohe Homesteads is located between the Wao Kele o Puna Forest Reserve and the town of Pāhoa in the Puna District of the County of Hawai`i.


Recent Observations:
[Lava flow] Lava flow continued to advance north northeast and has slowed since September 10 to a rate of 250 m/day (820 ft/day).

Hazard Analysis:
[Lava flow] Lava flow from Pu‘u ‘Ō‘ō vent could reach the northwest corner of Kaohe Homesteads within a day and the Pāhoa Village Road (government road) in Pāhoa within 20 days.

Remarks: The Pu‘u ‘Ō‘ō vent in the East Rift Zone of Kīlauea Volcano began erupting on January 3, 1983, and has continued erupting for more than 31 years, with the majority of lava flows advancing to the south. Over the past two years, lava flows have issued from the vent toward the northeast. The June 27th flow is the most recent of these flows and the first to threaten a residential area since 2010-2011. On June 27, 2014, new vents opened on the northeast flank of the Pu‘u ‘Ō‘ō cone and fed a narrow lava flow to the east-northeast. On August 18, the flow entered a ground crack, traveled underground for several days, then resurfaced to form a small lava pad. This sequence was repeated three more times over the following days with lava entering and filling other cracks before reappearing at the surface, in two of the cases farther downslope. Lava emerged from the last crack on September 6, forming a surface flow that initially moved to the north, then to the northeast, at a rate of 400 m/day (1,300 ft/day). Since September 10, the rate of advancement has slowed to 250 m/day (820 ft/day).

Contacts: HVO media contact
askHVO@usgs.gov

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While this VAN is in effect, regularly scheduled updates are posted at http://hvo.wr.usgs.gov/activity/kilaueastatus.php

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Friday, September 12, 2014 9:41 AM HST (Friday, September 12, 2014 19:41 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation continued, with a slight rise in lava level. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. A Civil Defense overflight yesterday at 12:30 pm showed the flow front was still moving in a general northeast direction, bringing it closer to the western boundary of Kaohe Homesteads (which is the eastern boundary of the Wao Kele o Puna forest reserve). The flow front at that time was 14.8 km (9.2 miles) from the vent, measured in a straight line, and 0.3 km (0.2 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 16.9 km (10.5 miles). Between September 6 and 10, the flow front advanced at approximately 400 meters (460 yards) per day. Between September 10 and 11 the advance rate dropped slightly to approximately 300 meters (330 yards) per day. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was only very slight deflationary tilt at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views this week have found small lava ponds within the northeast, north, and south pits. The southeast pit had a new lava pond with a small flow erupting onto the crater floor. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Inflationary tilt continued at Kīlauea's summit. The lava lake level rose slightly and was roughly 50 m (164 ft) below the Overlook crater rim this morning. There was a cluster of small earthquakes in the upper East Rift Zone over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Thursday, September 11, 2014 9:27 AM HST (Thursday, September 11, 2014 19:27 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation continued, with a slight rise in lava level. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. An HVO overflight yesterday afternoon observed that the flow front had shifted towards a more northeast direction, bringing it closer to the western boundary of Kaohe Homesteads (which is the eastern boundary of the Wao Kele o Puna forest reserve). The flow front at 2:45 pm yesterday was 14.5 km (9.0 miles) from the vent, measured in a straight line, and 0.6 km (0.4 miles) from the Forest Reserve/Kaohe Homesteads boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 16.6 km (10.3 miles). Between September 6 and 10, the flow front has advanced at approximately 400 meters (460 yards) per day. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes as they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was no significant change in tilt at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views yesterday found small lava ponds within the northeast, north, and south pits. The southeast pit had a new lava pond with a small flow erupting onto the crater floor. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Inflation continued at Kīlauea's summit. The lava lake level rose slightly and was roughly 55 m (180 ft) below the Overlook crater rim this morning. There was no major change in seismicity over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 9, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–7,600 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HVO/USGS Volcanic Activity Notice

Volcano: Kilauea (VNUM #332010)

Current Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE

Issued: Wednesday, September 10, 2014, 7:21 PM HST (20140911/0521Z)
Source: Hawaiian Volcano Observatory
Notice Number: 2014/H3
Location: N 19 deg 25 min W 155 deg 17 min
Elevation: 4091 ft (1247 m)
Area: HI Hawaii and Pacific Ocean

Volcanic Activity Summary: Between September 6 and 10, the June 27th flow advanced north then northeastward at an average rate of 400 m/d (0.25 mi/d). In this way, the flow had advanced approximately 14.5 km (9.0 miles straight-line distance) from the vent, or to within 0.6 km (0.4 miles) of the eastern boundary of the Wao Kele o Puna Forest Reserve, by the afternoon of September 10. At the average rate of advancement of 400 m/day (0.25 mi/day) since September 6, we project that lava could flow from its current location to the northwest edge of Kaohe Homesteads in 1.5 days and to the Pāhoa Village road (government road) in Pāhoa within 14-16 days if lava is not further confined within the cracks and down-dropped blocks within the East Rift Zone of Kīlauea volcano. These estimates will be continually refined as we track this lava flow.

Kaohe Homesteads is located between the Wao Kele o Puna Forest Reserve and the town of Pāhoa in the Puna District of the County of Hawai`i.

Recent Observations:
[Lava flow] Lava flow turned to the northeast and is advancing at a rate of 400 m/day (0.25 mi/day).

Hazard Analysis:
[Lava flow] Lava Flow from Pu‘u ‘Ō‘ō vent could reach the northwest edge of Kaohe Homesteads in 1.5 days and the government road in Pāhoa within 14-16 days.

Remarks: The Pu‘u ‘Ō‘ō vent in the East Rift Zone of Kīlauea Volcano began erupting on January 3, 1983, and has continued erupting for more than 31 years, with the majority of lava flows advancing to the south. Over the past two years, lava flows have issued from the vent toward the northeast. The June 27th flow is the most recent of these flows and the first to threaten a residential area since 2010-2011. On June 27, 2014, new vents opened on the northeast flank of the Pu‘u ‘O‘o cone that fed a narrow lava flow to the east-northeast. On August 18, the flow entered a ground crack, traveled underground for several days, then resurfaced to form a small lava pad. The sequence was repeated three more times over the following days with lava entering and filling other cracks before reappearing at the surface, in two of the cases farther downslope. Lava emerged from the last crack on September 6 and moved as a surface flow to the northeast.

Contacts: HVO media contact
askHVO@usgs.gov

Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While this VAN is in effect, regularly scheduled updates are posted at http://hvo.wr.usgs.gov/activity/kilaueastatus.php

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Wednesday, September 10, 2014 9:49 AM HST (Wednesday, September 10, 2014 19:49 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit inflation began last night, but no significant change in lava level occurred. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. A Civil Defense overflight this morning found that the flow front had advanced an additional 425 meters (460 yards) since yesterday morning. This puts the tip of the flow at 14.4 km (8.9 miles) from the vent, measured in a straight line, and 0.7 km (0.4 miles) from the Forest Reserve boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 16.4 km (10.2 miles). The flow front position this morning indicates a slight turn in direction from a north trend to a more northeast trend, bringing the flow closer to the Forest Reserve boundary over the past day. The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes a they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was minor deflation at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views this week have found small lava ponds within the northeast, north, and south pits in the crater. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Deflation continued at Kīlauea's summit through much of yesterday, but changed to inflation last night. The lava lake level did not change significantly and was roughly 60 m (197 ft) below the Overlook crater rim this morning. There was no major change in seismicity over the past day; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 2, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–6,700 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Tuesday, September 9, 2014 9:44 AM HST (Tuesday, September 9, 2014 19:44 UTC)


This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time.

KILAUEA VOLCANO (VNUM #332010)
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea continued to erupt at its summit and within the East Rift Zone, and gas emissions remained elevated. Summit deflation continued over the past day, and the lava lake level dropped in response. At the middle East Rift Zone, the front of the June 27th flow continues to advance through forest near Kaohe Homesteads, and surface breakouts are also present closer to Puʻu ʻŌʻō.

June 27th Lava Flow Observations: The June 27th lava flow remains active. An HVO flight early in the afternoon yesterday found that the flow had advanced ~280 m (~300 yards) north since a Civil Defense flight just after sunrise that morning (a span of ~6 hours), and the flow front had reached a large crack marked on the topographic base map (but not visible from the air). There was no evidence that the flow was entering this crack, if it exists.

A Civil Defense overflight this morning found that the flow front had advanced an additional 370 meters (400 yards) since yesterday afternoon. This puts the tip of the flow at 14.0 km (8.7 miles) from the vent, measured in a straight line, and 1.1 km (0.7 miles) from the Forest Reserve boundary. The actual length of the flow, measured along the lava tube axis (so that bends in the flow are considered) is 16.0 km (9.9 miles). The flow front is still in thick forest, creating smoke plumes as it engulfs trees and other vegetation, but fires are not spreading away from the flow.

Small breakouts also remain active closer to Puʻu ʻŌʻō, roughly midway along the length of the June 27th flow. None of these breakouts have been very vigorous recently, but are also producing smoke plumes a they creep into the adjacent forest.

Puʻu ʻŌʻō Observations: There was minor deflation at Puʻu ʻŌʻō over the past day. Glow was visible overnight above several outgassing openings in the crater floor. Aerial views yesterday found small lava ponds within the northeast, north, and south pits in the crater. The most recent sulfur-dioxide emission-rate measurement for the East Rift Zone was 400 tonnes per day (from all sources) on September 2, 2014.

Summit Observations: Deflation continued at Kīlauea's summit over the past day, but at a slowing rate. The lava lake level dropped with the deflation and was roughly 55-60 m (180-197 ft) below the Overlook crater rim this morning. There was a small increase in seismicity beneath the summit caldera, probably related to the ongoing deflation; seismic tremor at the summit remained low and varied with changes in spattering on the surface of the lava lake. GPS receivers spanning the summit caldera recorded about 5 cm (2 in) of extension between early May and early July. Since then, GPS line length has tracked changes in ground tilt. During the week ending on September 2, 2014, the elevated summit sulfur-dioxide emission rate was measured at 3,300–6,700 tonnes/day (see caveat below), and a tiny amount of particulate material was carried aloft by the plume.



Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. During 2013 and early 2014, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume.

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow continues to advance toward the northeast.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout pose no immediate threat to residential areas. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field Most of the flow field is within the closed-access Kahaualeʻa Natural Area Reserve (NAR) or the Wao Kele o Puna Forest Reserve (DLNR, OHA) and can only be viewed from the air. Under favorable weather conditions at night, distant glow from the active flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and from the end of the Chain of Craters Road and a few other areas within Hawaiʻi Volcanoes National Park.

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust.

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information:
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.



Update Archive

Older updates can be found using the HVO Alert Archive Search.

New Update Format

For more information about the Volcano Alert Level and Aviation Color Code, please see the U.S. Geological Survey's Alert Notification System for Volcanic Activity Fact Sheet (pdf) or the USGS Volcanic Activity Alert-Notification System web page.