Anatahan eruptions winding down

The third historical eruption of Anatahan may be winding down, according to a joint report issued by the Emergency Management Office and the U.S. Geological Survey.

In its latest report, the two agencies showed that since midday Thursday, the seismicity dropped abruptly, indicating that the explosions have ceased.

So far, the pause, punctuated occasionally by an hour or two of low amplitude tremors, has lasted about 32 hours, and may indicate that this eruptive phase is winding down, the agencies said.

The agencies said degassing is probably still continuing.

This pause in activity is the third since the eruptions began this month, stopping 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.

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 tremors.

Earlier, EMO personnel flew over the island and 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.

Anatahan remains off limits until further notice, with the exception of scientific expeditions, pursuant to a continuing emergency declaration by Gov. Juan N. Babauta. Conditions may change rapidly and all aircrafts should pass upwind of the island or beyond 30km downwind.

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 stopped in June.

Meanwhile, EMO, in conjunction with the National Weather Service on Guam, indicated yesterday that hazardous surf and small craft advisories remain in effect for Saipan, Tinian, and Rota.

EMO said hazardous surf remains due to a strong northeast trade-wind flow.

“Expect hazardous surf heights of 9 to 12 feet along northwestern clockwise through northeastern exposures,” EMO said.

Forecast for today feature northeast winds at 20 knots with wind waves of six to eight feet and northeast swells of four to six feet.

Northeast winds to intensify to 15 to 20 knots and wind waves at five to seven feet, with northeast swell at four to six feet are expected tonight.

The public is urged to avoid venturing to exposed beaches and reef lines due to high risk of rip currents and dangerous surf.

“These two events are life threatening to anyone entering the water,” EMO said.