|
|
17 January 2002
Views of 2220' rootless shield and 2300' growing hornito
|
med |
large |
|

|
med |
large |
|
| Left. Aerial view of
shiny pahoehoe crust on lava forming a low shield at the 2220-foot
breakout high on the upper flow field. Right. Geologist near left
edge of view gazes up at the smooth surface of the actively growing shield.
A rootless shield is a pile of lava flows built over a lava
tube rather than over a conduit feeding magma from within the earth.
Rootless shields along the tube system commonly have a flat top containing
a shallow lava pond. |
|
Aerial view of one flank of the 2220-foot rootless shield,
with a low bubbler in upper right and oozing lava near base of scene. The
texture of the flow surface appears almost silken.
|

|
med |
large |
|
|
med |
large |
|

|
med |
large |
|
| Left. Spirelike hornito
silhouetted against fume (center of view) towers above surrounding flows.
The hornito is built at the 2300-foot skylight on the main tube carrying lava
from Pu`u `O`o (right of view) to the coast. Right. The hornito is now a doublet,
5-6 m high, unusually steep and very fragile. Spatter from openings in the
roof of the lava tube has been building the hornito for the past week and
a half. Hissing, incandescent opening is hidden between the two spires.
Compare with views in this collection of same hornito taken on January 11 and with its
predecessor on January 4. |
25 January 2002
Rootless shields and hornitos along the main tube system
|
med |
large |
|

|
med |
large |
|
| Aerial views of the active
rootless shield at the 2220-foot elevation, along the master tube carrying
lava from Pu`u `O`o to the coastal flat. In left view, 150-200 m across,
lava oozes downslope toward camera. In right view, 25-50 m wide, a small
bubbling fountain feeds lava toward camera along right side of view, while
smooth crust on a lava pond is slowly breaking and sinking left of the
fountain. Note the developing crack in the crust (left center) with
incandescent lava oozing from it. The crust sinks because the underlying
bubbly lava is lighter and more buoyant. |
|
med |
large |
|

|
med |
large |
|
| Two views of new, spirelike
hornito at 2240-foot elevation, formed in past week just upslope from the
old 2240-foot skylight along the lava tube below Pu`u `O`o. This hornito
is unusually steep and narrow, almost a chimney. Two columns make up the
hornito, as the right-hand view shows. Already sulfur deposition is
extensive, making the hornito look prematurely old. |
|
Looking northwest at the 2300-foot hornito. This one began
to form between January 4 and January 11, on yet another older hornito.
Compare with views on January 17 for changes in past week. Blue box is about
50 cm long.
|

|
med |
large |
|
|
Close-up of the knuckle handshake between the two glowering
towers on the 2300-foot hornito.
|

|
med |
large |
|
31 January 2002
New rootless shield at 2240 feet, and a trio of hornitos
|
med |
large |
|

|
med |
large |
|
| Left. Smooth surface of
new shield growing above the 2240-foot skylight on the main tube from Pu`u
`O`o. A small breakout is taking place from a crack in the inflating
shield. Right. Volunteer geophysicist uses VLF (Very Low
Frequency) instrument to measure flux in lava tube near the new shield in
background. Note the gas mask, necessary in this obnoxious area. A rootless shield is a pile of lava flows built over a lava
tube rather than over a conduit feeding magma from within the earth.
Rootless shields along the tube system commonly have a flat top containing
a shallow lava pond. |
|
Eerie view of a family of hornitos. An existing old-timer (right) at site of the former 2300-foot skylight has been joined in past
week by two youngsters. Note the two figures between the two right-hand
hornitos.
|

|
med |
large |
|
Map of flows from Pu`u `O`o: November 13, 2001

Map shows lava flows erupted during the 1983-present activity
of Pu`u `O`o and Kupaianaha (see large
map). The flows active from December 17, 2000 through November 13,
2001 are shown in red; the active Kamoamoa flow is the westernmost red flow
descending Pulama pali and entering the ocean at
Kamoamoa. Lava is also pouring into the sea at the long-lasting East Kupapa`u
entry. From October 29 to November 10, lava also entered the water at Kupapa`u, 600 m southwest
of East Kupapa`u.
Most of the recent flows are fed from
breakout points at 2300-1700 feet, above Pulama pali in the northern part of the large red area.
Lava re-entered the sea near Kamokuna (just east of Kamoamoa) on January 21, 2001, but soon stopped when activity
shifted from the western to the eastern branch of the flow. Since then, activity
has been divided between the eastern and western branches. Breakouts from the
eastern tube system have destroyed hundreds of meters of the Royal Gardens
access road.
Lava has been entering the ocean and building a large bench at East
Kupapa`u since April 25. A tiny trickle of lava fed through the western tube system dripped into the water
just east of Kamoamoa on May 31 but stopped within a day. Thereafter, all
lava leaving the island went through the East Kupapa`u entry until September
28-29, when the entry at Kamoamoa started. Yet a third ocean entry began on October 29, near the old Kupapa`u point, 600 m southwest of East Kupapa`u;
this entry stopped on November 10.
The URL of this page is
http://hvo.wr.usgs.gov/multimedia/archive/2002/Jan/17-25-31.html
Contact:
hvowebmaster@usgs.gov
Updated: 24 February 2002 (DAS)
|