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Eruptions in Philippines, Japan studied for possible connection

Published Oct. 13, 2005

Within days of each other, a pair of long-dormant volcanoes erupted in the Far East. Mere coincidence? Or is something strange going on in the belly of the earth? Most vulcanologists suspect coincidence.

"There isn't any connection," said David Lescinsky, a vulcanologist at Smithsonian Institution and a member of the Global Vulcanism Network, who is tracking the eruptions of Mount Unzen in Japan and Mount Pinatubo in the Philippines. "These are two major ones, but it is not unique that they are occuring at same time."

Although most geologists believe the nearly simultaneous eruptions of two volcanoes is a coincidence, some are investigating the possibility the eruptions may be linked to a lurch of one of the tectonic plates that make up Earth's crust. The two volcanoes are situated on the same plate. The idea, however, appears to be a long shot.

At any one time, several volcanoes are bubbling away or exploding, someplace in the world, often in its more obscure corners. Lescinsky said that in the last month more than a dozen volcanoes have erupted, or at least belched significantly. This level of activity is normal. We just don't hear about it if happens in such places as Ol Doinyo Lengai in Tanzania, Yasur in Vanuatu, Langila in Papua New Guinea, Kliucheskoi in the Soviet Union, and Lescinsky's personal favorite tongue-twister, Lewotobi Laki-Laki in Indonesia. All of these volcanoes came to life in the last few weeks.

Based on an analysis of wood charred during its last eruption, scientists believe it's been 600 years since Mount Pinatubo blew its top. Japan's Mount Unzen is on a bit faster schedule. It had last erupted 150 years ago.

When long-dormant volcanoes do erupt, they tend to erupt in spectacular and dangerous ways. Mount Pinatubo, for example, literally exploded, lofting a column of smoke miles high. The smoke currently is being tracked by weather satellites, to warn airplane pilots away from its path. Such large eruptions are capable of lowering worldwide temperatures, as the soot and ash shield the earth from incoming radiation.

Three major new eruptions rocked Mount Pinatubo late Wednesday night and early today.

"I rushed outside and there it was. It looked like a nuclear bomb had gone up, a huge mushroom cloud over the volcano," said Victor Gomez, a 53-year-old American who owns a restaurant outside the gates of Clark Air Base. The 4,800-foot volcano is about 10 miles west of the air base and 50 miles north of Manila.

The latest eruptions forced the Air Force to evacuate hundreds of American volunteers who had stayed behind to guard the base and tend sensitive communications equipment. Most of the 16,000 Americans who live and work at Clark were evacuated on Monday.

Scientists say that Clark could be partly smothered by rock and ash in a larger eruption, and that the threat posed by the volcano may not end for years.

American officials have refused to say whether nuclear weapons are stored at Clark. But they denied local news reports suggesting a radiation danger if weapons depots on the base were hit by molten rock.

Mudslides were reported after fierce thunderstorms and lightning lit afternoon skies eerily darkened from the giant volcanic clouds that dropped as much as two inches of coarse gray ash and fist-sized pieces of pumice on villages, trees and fields along a 50-mile stretch southwest of the volcano.

Villagers tied wet kerchiefs on their faces and used rakes, shovels and pieces of wood to push the blanket of snow-like ash from roads. At times, winds whipped the grit into the air, forcing cars to use windshield wipers and headlights in blizzard-like conditions.

Despite the volcano's fury, there was little reported damage and only two fatalities from the daylong series of eruptions. A Filipino serving with the U.S. Navy was killed when his car collided with a bus on an ash-slicked road and a boy was reported to have died after inhaling sulfuric fumes that began to seep from the volcano last weekend.

Of 37 volcanoes around the world currently listed as active, 29, including Mount Unzen in Japan and Mount Pinatubo in the Philippines, both of which erupted Wednesday, lie on the Pacific "Ring of Fire" and, according to specialists, are products of motion by sections of the Pacific floor.

In recent months three volcanoes on the Japanese island of Kyushu have been active. Of those, Mount Unzen has been the most threatening, having already killed 38 people and evoking memories of its last eruption, in 1792. That eruption set off a tsunami, a huge sea wave, that killed 15,000.

The movement of sections of the Pacific floor often leads to explosive eruptions, as in the 1980 eruption of Mount St. Helens in Washington State.

_ Information from the New York Times and the Los Angeles Times was used in this report.

Major U.S. volcanoes

Volcano/site/last eruption

Akutan, Alaska; 1989

Amukta, Alaska; 1963

Aniakchak, Alaska; 1931

Augustine, Alaska; 1986

Bogoslof, Alaska; 1931

Chiginagak, Alaska; 1929

Cinder Cone, Calif.; 1851

Cleveland, Alaska; 1987

Gareloi, Alaska;1982

Great Sitkin, Alaska; 1974

Iliamna, Alaska; 1978

Kagamil, Alaska; 1929

Kanaga, Alaska; 1933

Katmai, Alaska; 1974

Kiska, Alaska; 1969

Korovin, Alaska; 1987

Lassen Peak, Calif.; 1921

Martin, Alaska; 1960

Mageik, Alaska; 1946

Makushin, Alaska; 1987

Mount Baker, Wash.; 1870

Mount Hood, Ore.; 1801

Mount Rainier, Wash.; 1882

Mount Shasta, Calif.; 1855

Mt. St. Helens, Wash.; 1986

Okmok, Alaska; 1988

Pavlof, Alaska; 1988

Pogromni, Alaska; 1964

Redoubt, Alaska; 1990

Seguam, Alaska; 1977

Shishaldin, Alaska; 1987

Spurr, Alaska; 1953

Trident, Alaska; 1974

Veniaminof, Alaska; 1987

Westdahl, Alaska; 1964

Yunaska, Alaska; 1937

Haleakala, Hawaii; 1790

Hualalai, Hawaii; 1801

Kilauea, Hawaii; 1990

Mauna Loa, Hawaii; 1987