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Anatahan emits thick ash plume
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Posted on Jun 23 2005
Anatahan’s erupting volcano emitted thick ash clouds Wednesday, but the activity subsided slightly yesterday.
The U.S. Geological Survey and the Emergency Management Office said thicker ash clouds became evident through the Air Force Weather Agency’s satellite imagery. The activity lasted about four hours.
The volcano then started to emit thick ash clouds again late Wednesday night, the agencies said.
Yesterday, the volcano released “moderately dense” cloud of ash and steam that rose to about 5,000 feet. The plume extended about 150 nautical miles to the west, the agencies said.
Thin ash and volcanic smog extended out to 1,075 nautical miles to the west beyond that plume, and to 950 nautical miles north-northwest of Anatahan.
Despite the fluctuating intensity of volcanic ash emissions, the agencies said there was no significant change to seismic records; but the agencies said tremor levels remained high.
On Sunday, the volcano displayed a series of eruptions that sent ash to 50,000 feet in the air. It matched the intensity of Anatahan’s strongest historical eruption on 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 ash to high altitudes beginning at 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 said conditions could change rapidly, and volcanic activity could suddenly escalate.
