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Anatahan volcano settles down
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Posted on Jan 21 2005
Explosion activities on Anatahan ceased for the third time during this eruption, according to the latest joint report issued by the Emergency Management Office and the U.S. Geological Survey.
In a report, the agencies indicated that during mid-day Thursday, Jan. 20, the seismicity dropped abruptly, which indicated that the explosions have ceased.
The current pause in activities has lasted about eight hours, by far the longest pause during the eruption this year.
The eruption appeared to have stopped twice for a few hours between Jan. 15 to Jan. 19, before resuming at higher intensity, topping previous highs of 10,000 feet with explosions resulting in ash rising to about 15,000 feet. Satellite photos show a plume of vog—volcanic smog—trailing about 60 km downwind.
Earlier, EMO indicated that the explosions, featuring ash and pyroclastic rocks one meter or more in diameter, were being expelled hundreds of feet into the air and falling back to form a new cinder cone about 120 meters in diameter.
The explosions grew in size and rate, peaking on Jan. 9 with explosions occurring every three to 10 seconds.
The third historical eruption of Anatahan, an uninhabited island 120 miles north of Saipan, began on Jan. 5 preceded by two days of a few small long-period earthquakes and one day of harmonic tremor.
Anatahan remains off limits until further notice, with the exception of scientific expeditions, pursuant to a continuing emergency declaration by Gov. Juan N. Babauta.
Anatahan had no historical eruptions prior to 2003. On May 10, 2003, an eruption sent ash to over 30,000 ft and deposited about 10 million cubic meters of material over the island and sea. The eruption ceased in June.
The second batch of eruptions began about April 9, 2004 and ended on July 26, although visitors to the island three months later could still see very small amounts of steam and ash rising 100-200 ft above the crater rim and could smell sulfur dioxide near the crater.
