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Seismicity remains high on Anatahan
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Posted on Jun 21 2005
Tremor levels on Anatahan remained high yesterday after Sunday’s strong volcanic eruption that sent ash to 50,000 feet.
The U.S. Geological Survey and the Emergency Management Office said that ash emissions had become moderately dense.
The agencies said that ash and steam rose to about 10,000 feet, moving northwest and extending about 375 nautical miles. Beyond that, thin ash and volcanic smog extended northerly to 815 nautical miles northwest of the island.
Anatahan’s volcano displayed Sunday afternoon a series of eruptions that sent ash to 50,000 feet. The eruptions matched the intensity of the volcano’s strongest historical eruption of record last April 6, which also sent ash to 50,000 feet.
Seismicity on Anatahan had been increasing in the past days before Sunday’s 2.6-minute eruptive pulse spewed out ashes to high altitudes beginning at about 3:25pm. The volcano had the highest tremor levels Saturday since early May.
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.
During a strong eruption last April 6, the agencies said the volcano expelled about 50 million cubic meters of ash, which it spewed out to 50,000 feet. The agencies have yet to estimate the volume of ash emitted in Sunday’s strong explosion. But the volcano has been continuously emitting huge amounts of ash for the past several weeks.
