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Tremors continue at Anatahan
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Posted on Jun 17 2005
Seismicity on Anatahan significantly increased Thursday, reaching its highest level in the last two months and surpassing tremor levels during last Saturday’s eruption.
The volcano’s ash emission, however, appeared tamer, although the U.S. Geological Survey and the Emergency Management Office reported that a dense ash cloud continued rising to 10,000 feet yesterday.
The agencies said small long-period earthquakes and explosions occurred as often as several per minute. They said tremor levels remained high yesterday, although they were slightly lower than Thursday’s seismicity levels.
Citing satellite monitoring by the Air Force Weather Agency, the agencies said the ash and steam plume extended about 200 nautical miles west, while thin ash and volcanic smog extended out 800 nautical miles toward the west-northwest.
The volcano erupted Saturday last week, spewing out thick clouds of ash to 45,000 feet, its second strongest eruption in recorded history. The volume of ash emitted by the volcano in that eruption has yet to be estimated.
During its strongest eruption last April 6, the volcano expelled about 50 million cubic meters of ash, which reached 50,000 feet.
The agencies maintained that aircraft should take extra precaution within 10 nautical miles of Anatahan, advising them to pass upwind of the island or beyond 10 nautical miles downwind. They pointed out that conditions could change rapidly, and volcanic activity could just suddenly escalate. (John Ravelo)
