Recent Kilauea Status Reports, Updates, and Information Releases
HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
Sunday, May 20, 2012 8:30 AM HST (Sunday, May 20, 2012 18:30 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: No significant changes; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from coastal plain breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeters showed no significant changes over the past day; the summit remains in an inflated state. The lava lake at Halema`uma`u remains at a high level, with the level being relatively steady over the past day. A minor rise-fall event happened around 6:30 am this morning, and spattering over the past day has been common along the south margin of the lake. The high points in lava level over the past few days were measured using a laser rangefinder to be 60 m (200 ft) below the floor of Halema`uma`u Crater - among the highest levels we have measured for the lake. The most recent (preliminary) sulfur dioxide emission rate measurement was 600 tonnes/day on May 18, 2012. There was no ash collection this morning, but presumably small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were carried out of the vent in the gas plume.
The GPS network recorded weak extension over the past few months. Seismic tremor levels were low. Eleven earthquakes were strong enough to be located beneath Kilauea volcano over the past day: 5 on the upper east rift zone and 6 on the south flank.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. Webcam images showed that the active flows on the coastal plain made little advancement towards the ocean overnight and were still about 1 km (0.6 miles) from the water; there is still no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded no significant change over the past day. The eastern lava pond in Pu`u `O`o crater remained in view of the webcam, and an apparent small collapse of the northern rim of the eastern pit occurred around 9 pm last night, enlarging the pit (and lava pond within) slightly. A tiny lava flow was erupted from the southern vent in the crater around 11 am yesterday. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 500 tonnes/day on May 18, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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
Saturday, May 19, 2012 8:35 AM HST (Saturday, May 19, 2012 18:35 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: Summit inflation continued; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeters showed that gradual inflation at the summit has persisted since the last DI event three days ago. The lava lake at Halema`uma`u remains at a high level, with fluctuations that resulted in the lava spilling over the deep inner ledge on four occasions over the past day: around 1 pm yesterday, and around 1 am, 4 am and 7 am this morning. The high points in lava level were measured using a laser rangefinder to be 60 m (200 ft) below the floor of Halema`uma`u Crater - among the highest levels we have measured for the lake. Spattering location and intensity fluctuated several times over the past day as well. The most recent (preliminary) sulfur dioxide emission rate measurement was 600 tonnes/day on May 18, 2012. Small amounts of ash-sized tephra were collected this morning, including fresh bits of spatter from spattering at the edge of the lava lake.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels were low. Nineteen earthquakes were strong enough to be located beneath Kilauea volcano: 5 at the summit, 6 on the south flank, 7 on the east rift zone and 1 off the south coast.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. HVO geologists in the field yesterday mapped active breakouts about 1.1 km (0.7 miles) from the ocean. Webcam images showed that these flows on the coastal plain made little advancement towards the ocean overnight; there is still no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded continued inflation over the past day, though some of this may be influenced by recent rainfall. The eastern lava pond in Pu`u `O`o crater remained in view of the webcam, and was highly dynamic over the past day with shifting spatter sources. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 500 tonnes/day on May 18, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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, May 18, 2012 7:08 AM HST (Friday, May 18, 2012 17:08 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: Summit inflation continued; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeters showed that gradual inflation at the summit has persisted since the last DI event two days ago. The lava lake at Halema`uma`u remains at a high level, with fluctuations that resulted in the lava spilling over the deep inner ledge on three occasions: around 3 pm and 10 pm yesterday, and 6 am this morning. The high points in lava level were equivalent to slightly more than 60 m (200 ft) below the floor of Halema`uma`u Crater - among the highest levels we have measured for the lake. Spattering location and intensity fluctuated several times over the past day as well. The most recent (preliminary) sulfur dioxide emission rate measurement was 700 tonnes/day on May 17, 2012. Although not measured this morning, small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were likely wafted out of the vent within the gas plume and deposited on nearby surfaces.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels were low. Eleven earthquakes were strong enough to be located beneath Kilauea volcano: 3 at the summit, 3 on the south flank, 3 on the east rift zone and 2 on the southwest rift zone.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. Webcam images showed that the flows on the coastal plain made little if any advancement towards the ocean over the past day; there is still no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded continued inflation over the past day, though some of this may be influenced by recent rainfall. The eastern lava pond in Pu`u `O`o crater remained in view of the webcam, and was highly dynamic over the past day with shifting spatter sources. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on May 8, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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
Thursday, May 17, 2012 8:37 AM HST (Thursday, May 17, 2012 18:37 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: DI inflation continued; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: DI inflation continued over the past day, and appears to have peaked early this morning. Impressive spattering (see recent photos and video) was observed yesterday at the west margin of the lava lake in Halema`uma`u Crater, but shifted last night following a rise/fall event to its more typical position in the east and south margin of the lake. A laser rangefinder measurement yesterday put the lava lake at 65 m (210 ft) below the floor of Halema`uma`u Crater - among the highest levels we have measured for the lake; the lava rose slightly above this level briefly around 9 pm last night, spilling over the deep inner ledge, during a rise/fall event. The most recent (preliminary) sulfur dioxide emission rate measurement was 800 tonnes/day on May 16, 2012. Although not measured this morning, small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were likely wafted out of the vent within the gas plume and deposited on nearby surfaces.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels were low. Eighteen earthquakes were strong enough to be located beneath Kilauea volcano: 7 at the summit, 6 on the south flank and 5 on the east rift zone.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. Webcam images showed that the flows on the coastal plain made little if any advancement towards the ocean over the past day; there is still no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded continued DI inflation over the past day. The eastern lava pond remained in view of the webcam, and rose slightly this morning. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on May 8, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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, May 16, 2012 8:32 AM HST (Wednesday, May 16, 2012 18:32 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: One-to-two-day-long back-to-back DI tilt events continued during which lava lake levels rose with inflation and fell with deflation; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeter network recorded the switch to DI inflation at 7 pm last night and the lava lake level started to rise at about the same time; late last night, the spattering sink at the southwest edge of the lake became active increasing to very vigorous early this morning pushing short flows over the inner ledge. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on May 11, 2012. Although not measured this morning, small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were likely wafted out of the vent within the gas plume and deposited on nearby surfaces.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels were low. Seven earthquakes were strong enough to be located beneath Kilauea volcano: 2 within the southwest rift zone, 3 beneath the south summit area, and 2 on south flank faults.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. Webcam images showed that the flows advanced more overnight than during the past 2 nights across the coastal plain overnight but there was no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded the switch to DI inflation last night. The eastern pond lava level remained stable even during a brief lava emission from the south crater floor source between 5 and 6 pm last night. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on May 8, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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
Tuesday, May 15, 2012 6:06 AM HST (Tuesday, May 15, 2012 16:06 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: Back-to-back DI tilt events were shorter but continued during which lava lake levels rose with inflation and fell with deflation; lava was generally at high levels in both summit and rift vents. At Pu`u `O`o, glow persisted from the usual sources and lava was visible in the eastern collapse pit; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeter network recorded another DI deflation around 5 pm last night when the lava lake level started to drop; a laser rangefinder measurement yesterday placed the lava lake surface about 67 m (220 ft) below the Halema`uma`u Crater floor - a pretty high level. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on May 11, 2012. Although not measured this morning, small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were likely wafted out of the vent within the gas plume and deposited on nearby surfaces.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels increased slightly. Seven earthquakes were strong enough to be located beneath Kilauea volcano: 2 within the upper east rift zone, 2 within the middle east rift zone, and 3 on south flank faults.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. Webcam images showed that the flows advanced little across the coastal plain overnight; consequently, there was no ocean entry. The Kalapana Viewing Area folks reported continuing breakouts on the pali last night.
The tiltmeter on the north flank of Pu`u `O`o cone recorded fluctuations that did not seem related to summit tilt. The eastern pond lava level continued to rise slowly with an actively spattering sink on the wall opposite the webcam. Seismic tremor levels near Pu`u `O`o remained low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on May 8, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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, May 14, 2012 8:21 AM HST (Monday, May 14, 2012 18:21 UTC)
This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available using the menu bar above), was prepared by the USGS Hawaiian Volcano Observatory (HVO). Hawai`i Volcanoes National Park status can be found at http://www.nps.gov/havo/ or 985-6000. All times are Hawai`i Standard Time.
KILAUEA VOLCANO (CAVW #1302-01-) 19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m) Current Volcano Alert Level: WATCH Current Aviation Color Code: ORANGE
Activity Summary for past 24 hours: Back-to-back DI tilt events were shorter but continued during which lava lake levels rose and fell with tilt; lava was generally at high levels. At Pu`u `O`o, glow persisted from the usual sources with the east lava pond and a brief lava flow visible; to the southeast, surface flows from new breakouts advanced but had not reached the ocean. Seismic tremor levels were generally low; gas emissions were elevated.
Past 24 hours at Kilauea summit: The summit tiltmeter network recorded the switch to DI inflation a about 9:30 pm last night and the lava lake level rose with it; between 1:20 and 3 am this morning lava rose rapidly during a rise/fall event and washed over the inner ledge before a new spattering sink appeared along the north lake edge and the lake level rapidly drained into it; the north sink and the northward circulation pattern stopped before 4 am and normal northwest-to-southeast circulation resumed. The most recent (preliminary) sulfur dioxide emission rate measurement was 300 tonnes/day on May 11, 2012. Although not measured this morning, small amounts of ash-sized tephra, including fresh bits of spatter from spattering at the edge of the lava lake, were likely wafted out of the vent within the gas plume and deposited on nearby surfaces.
The GPS network recorded possible weak extension although the long-term trend is difficult to see through the muddle of DI events. Seismic tremor levels were slightly elevated with appearance of new spattering sinks in the lake, but overall at low values. Seventeen earthquakes were strong enough to be located beneath Kilauea volcano: 1 deep quake beneath the southwest rift zone, 2 beneath Halema`uma`u Crater, 8 mostly deep quakes beneath the upper east rift zone (near Pauahi Crater), 2 within the middle east rift zone (near Pu`u `O`o), and 4 deep quakes on south flank faults.
Background: The summit lava lake is deep within a ~160 m (520 ft) diameter cylindrical vent with nearly vertical sides inset within the east wall and floor of Halema`uma`u Crater. Its level fluctuates from about 60 m to more than 150 m (out of sight) below the floor of Halema`uma`u Crater. The vent has been mostly active since opening with a small explosive event on March 19, 2008. Most recently, the lava level of the lake has remained below an inner ledge (60 m or 200 ft below the floor of Halema`uma`u Crater on May 9, 2012) and responded to summit tilt changes with the lake receding during deflation and rising during inflation.
Past 24 hours at the middle east rift zone vents: Lava flow activity continued on the pali and the coastal plain southeast of Pu`u `O`o. An HVO geology crew mapped the active flows about 1.4 km (0.9 mi) from the coast yesterday. Webcam images showed that the flows advanced little across the coastal plain overnight. Consequently, there was no ocean entry.
The tiltmeter on the north flank of Pu`u `O`o cone recorded fluctuations that did not seem related to summit tilt. Glow has been strong from the lava pond within the collapse pit on the east edge of the crater and the pond lava level rose into PTcam view Saturday night and continued to rise through this morning with a strong spattering sink on the wall opposite the webcam. Just before 9 am yesterday, a brief short lava flow issued from the south glowing source. Seismic tremor levels near Pu`u `O`o were low. GPS receivers on opposite sides of the cone recorded weak extension. The most recent (preliminary) sulfur dioxide emission rate measurement was 400 tonnes/day on May 8, 2012, from all east rift zone sources.
Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and has continued since at Pu`u `O`o Cone, or from vents within a few kilometers to the east or west, with few interruptions. A fissure eruption on the upper east flank of Pu`u `O`o Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawai`i Volcanoes National Park in early December. The ocean entry has been inactive since late December but the flows have remained intermittently active on the pali and the coastal plain. In general, activity waxes with inflation and wanes with deflation.
Hazard Summary:East rift vents and flow field - near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume; potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. All recently active lava flows are within Hawai`i Volcanoes National Park, adjacent State land managed by the Department of Land and Natural Resources, and private property within the Royal Gardens subdivision; the lava flows do not pose a hazard to any structures not already within the County-declared mandatory evacuation zone. Kilauea Crater - ash and Pele's hair can be carried several kilometers downwind; potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.
Viewing Summary:East rift zone flow field - Active lava flows within the closed-access Kahauale'a Natural Area Reserve (NAR) and the evacuated Royal Gardens subdivision can only be viewed from the air. Under favorable weather conditions, the flows can be seen from the County Viewing Area at Kalapana (Lava hotline 961-8093) and in the R2, R3, and R4 webcams. Pu`u `O`o Cone and Kilauea Crater - these areas are within Hawai`i Volcanoes National Park; access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm.
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/
A definition of alert levels can be found at http://volcanoes.usgs.gov/activity/alertsystem/index.php
Definitions of Terms Used:
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.
fill-and-drain, rise/fall cycles or high lava stands: one of the cyclical behaviors exhibited by the summit lava lake. A cycle starts with a rise in lava level, a decrease in summit tremor amplitude, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level, seismic tremor amplitude will increase for a short time (a seismic tremor burst), and summit tilt will return to its previous level. Although not measured continuously, spot checks of gas emissions demonstrate that far less gas is released during the high lava stand than during its draining phase suggesting that, during the high lava stand, lava is puffed up with gas trapped by crusts on the lava surface; the gas plume will also get thin and wispy during these cycles returning to more robustness afterward.
perched lava lake: a lava lake within a rim that is progressively built up by overflows of lava that have cooled and solidified. The most recent example of a perched lava lake is currently active within Pu`u `O`o maintaining a rim standing several meters (yards) above the crater floor. In many ways, a perched lava lake resembles an above-ground swimming pool. Overflows from the pond add layers to the surrounding crater floor building it higher; the overflows also build up the perched lake rim, continually keeping the lake rim raised above the floor.
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).
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.
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 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 140 m (460 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at the pit floor, and is about 200 m (660 ft) deep. As of November, 2009, a lava pond surface has been visible in a hole in the floor of this pit.
glow: light from an unseen source; indirect light.
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).
CD: Hawai`i County Civil Defense
tonne: metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 1.1 English tons.
tephra: all material deposited by fallout from an eruption-related plume, regardless of size.
ash: tephra less than 2 mm (5/64 inches) in size.
microradian: a measure of angle equivalent to 0.000057 degrees.
More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.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.
