Posted on: Saturday, October 2, 2004
Hawai'i volcano expertise tapped
By Kevin Dayton
Advertiser Big Island Bureau
HILO, Hawai'i — Scientists at Cascades Volcano Observatory in Vancouver, Wash., have asked Hawai'i scientists for equipment to help them monitor the rumbling Mount St. Helens. But no Hawai'i scientists have been dispatched yet to study the awakening volcano.
At least a half-dozen staff members at the Hawaiian Volcano Observatory on the Big Island studied Mount St. Helens either before or after the 1980 eruption, and the scientists were closely following reports of the steam and ash spewed by the volcano yesterday.
"We learn from every eruption," said Richard Hoblitt, staff geologist for the Hawai'i observatory. "There are new methods and techniques that are coming online all the time, and each eruption offers the opportunity to test these new techniques and see if they provide more advanced warning to better predict the outcome of eruptions."
Hoblitt said the Hawai'i scientists were trying to assemble equipment, including a remote camera on the rim of the crater to record activity in the restless volcano and transmit the images to scientists working a safe distance away. The Hawai'i staff uses similar equipment to transmit images from the Pu'u 'O'o vent on the Big Island.
Hoblitt, who studied Mount St. Helens before the 1980 eruption and later as a staff member at the Cascades observatory for 15 years, said the Mount St. Helens and Kilauea volcanoes are quite different.
Magma from the Hawai'i volcano is basaltic, rich in iron and magnesium. Volcanoes here are stationed over "hotspots" that melt rock, causing the heated rock to rise to the surface because it is less dense than surrounding rock.
Mount St. Helens is a subduction zone volcano, meaning it is at a point where one tectonic plate of Earth's crust plunges beneath another. When the crust being thrust below the surface reaches about 60 miles deep, the rock melts and rises, creating a volcano.
The steam explosions reported at Mount St. Helens yesterday probably were not generated by gases bursting from magma, but rather steam explosions from heated groundwater, Hoblitt said.
Reports yesterday said scientists still had not detected increased levels of telltale gases, such as sulphur dioxide and carbon dioxide, that are associated with magma movement, Hoblitt said.
Hoblitt and other scientists are predicting an eruption of Mount St. Helens would be quite different from the one in 1980, in part because the volcano was altered by the 1980 event.
In that eruption, magma rising inside the volcano caused the north side of the volcano to bulge and eventually collapse on May 18, 1980. That suddenly released the pressure that had accumulated inside, allowing gases to escape in an enormous, deadly explosion.
Reach Kevin Dayton at kdayton@honoluluadvertiser.com or (808) 935-3916.
