New lava lake sighted at Kilauea

Not sure how it was kept quiet for most of the week (well, at least to me), but geologists at the HVO have noticed a new lava lake in Halemaumau Caldera on Kilauea (Hawai’i). The lava lake is around 330 feet (~100 meters) below the crater rim and ~160 feet (50 meters) across with sections of reddish, glowing lava and black crust on the surface. It seems that an explosion on Tuesday helped reveal the lava lake from the surface. The USGS has posted some video of the lava lake for your enjoyment. There are only a few active lava lakes worldwide (such as those at Villarrica in Chile and Erebus in Antarctica), so it is always exciting when a new one forms. The longevity of lava lakes is controlled (partially) by the supply rate of magma to the vent area, so it will be interesting to see how long it lasts.

UPDATE 9/7/2008

nnHere is the official word on the lava lake from the USGS:n

For the first time since the new vent opened in Halema`uma`u Crater onnMarch 19, HVO scientists in a helicopter hovering over the crater werenable to see the surface of a sloshing 50 m (160 ft) diameter lava lakenabout 100 m (330 ft) below the vent rim. HVO scientists have speculatednthat a lava pond existed a few hundred meters below the vent, but have notnbeen able to get visual confirmation until this morning.nn

A second viewing early this afternoon revealed a roiling pond with

nmultiple bursting bubbles changing into a central upwelling circulation

npattern. The lake level dropped slightly before the cycle restarted. This

nbehavior has been witnessed before, most recently in Pu`u `O`o vents and

nthe July 21 lava ponds on Kilauea’s east rift zone, and is known as ‘gas

npistoning.’ One model explains pistoning as small gas bubbles coalescing

ninto larger bubbles beneath a crust on a lava pond, rising to the surface,

nand then bursting. The released pulse of hot gas carries rock dust from

nthe collapsing vent walls, bits of the lava lake crust, and small amounts

nof spatter.

nn

The Halema`uma`u vent has produced six significant explosive eruptions in

nthe past 5.5 months, most recently on September 2, 2008 at 8:13 p.m.

nH.s.t., during which noteworthy amounts of fresh lava spatter and lithic

nmaterial (rock fragments and dust) were ejected on to the crater rim. Just

nprior to this event, incandescence from the vent was almost nonexistent

nexcept for brief pulses of glow.

nn

Nearly eight hours later, Kilauea’s summit abruptly inflated, signaling

nthe end of 39 hours of deflation. Summit deflation-inflation (DI) events

nhave been observed at least 20 times since the Halema`uma`u vent opened.

nEach DI event has been interpreted as the fall and subsequent rise in

nmagma levels beneath the summit.

nn

Less than 8 hours after inflation started, episodic tremor bursts began

nwhich are visible at night as pulses of bright incandescence every 5-6

nminutes. Episodic tremor bursts have been a nearly constant feature of

nthe Halema`uma`u vent over the past few months and were one of the early

npieces of evidence pointing toward a gas pistoning source.

nn

This unusually bright incandescence over the past two nights and the

nvolume of material erupted on September 2 are consistent with a lava

nsurface at relatively shallow depths beneath the vent. Molten lava is not

ndirectly visible from the Jaggar Museum overlook, but that vantage point

nprovides excellent views of the glowing vent at night.

nn

Jim Kauahikaua, Scientist-in-Charge

nUSGS Hawaiian Volcano Observatory