Tuesday, March 25, 2008

Halema'uma'u erupting! First time since 1982.

Halema'uma'u Crater, the firepit of Kīlauea, is erupting for the first time in 26 years.
(Image: Hawaiian Volcano Observatory image of ash plume from Halema'uma'u. Credit: USGS.)
In a buildup that has lasted more than a week, Halema'uma'u first began pumping out increased amounts of sulfurous gas, then threw boulders across the landscape in what was described as a gas explosion. Sunday night, it began erupting small amounts of lava and large amounts of ash.
Much of the landscape around the Kīlauea Caldera is covered with ash from previous eruptions, so this is not unheard-of.
The implications of the ash plume are potentially severe. It can damage aircraft engines that fly through it. It can harm human lungs.
“There is now continuous emission of ash from the new gas vent in Halema`uma`u Crater, turning the formerly white cloud of fume a dusty-brown color. The top of the ash plume, which is currently being blown to the southwest of the Crater, reaches 0.5 to 1.0 mile above ground level. Hawai`i aviation agencies have been notified of the potential hazard to aircraft,” the Hawaiian Volcano Observatory said in its daily update Monday.
Observatory staffers began seeing glowing material erupting Sunday night from a 100-foot-wide vent that is within the crater and below the crater overlook. The overlook and parts of the Chain of Craters road are closed to the public because of the health and safety hazards.
The eruption as of the most recent update is not the classic fountain of lava, but more of a spattering of molten rock. Geologists searching the area yesterday found a range of volcanic products, including long, thin strands and small gobs, which are known as Pele's hair and Pele's tears. The biggest pieces, the observatory said, are gobs of about 4 inches across.
“The amount of lava erupted from the vent last night was small, but it represents the first lava erupted from anywhere in Halema`uma`u since 1982. Previous eruptions included lava flowing into the crater from fissure eruptions on its southwest rim in 1974 and 1971 and an 8 month eruption in Halema`uma`u in 1967-1968 that created a lake of lava that covered the entire crater floor,” the observatory said.
For more on the current eruption, see the RaisingIslands.com post at raisingislands.blogspot.com/2008/03/quiet-volcano-gets-explosive.html.
Updates are available at the observatory website at hvo.wr.usgs.gov.
© 2008 Jan W. TenBruggencate