High level activity continues on Anatahan

High level of eruptive activity continues at Anatahan, with fluctuating explosions experienced during the past couple of days, according to the latest report issued by the Emergency Management Office and the U.S. Geological Survey yesterday.

The agencies indicated that the eruptions stopped for a couple of hours on Saturday before its magnitude surged again to about 50 percent higher than the previous high.

According to EMO geophysical seismic technician Juan Takai Camacho, the eruption resulted in pyroclastic rocks and ash being thrown about 15,000 feet into the air, surpassing the 10,000 feet witnessed by EMO personnel during an overflight on the island on Jan. 7. Rocks of 1 meter or more in diameter were observed during that flight.

The eruption declined for several hours on Sunday and stopped for about eight hours before returning to stable conditions, with explosion signals escalating in intensity but occurring at a less frequent rate, averaging a few explosions per minute.

The eruption surged again late Monday and dropped back to stable conditions around midnight.

“We’re going to continue to closely monitor the activity,” Camacho said yesterday.

The report indicated that, with the current level of eruptive activity, ash could be in the air to a few tens of kilometers, but severe weather is obscuring satellite images.

The third historical eruption of Anatahan, an uninhabited island about 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.

On Jan. 6, seismicity changed from continuous harmonic tremor to frequent strombolian explosions. A low plume of thin ash and gas was reported rising several hundred feet and blowing 60km downwind. The amplitude of the explosions slowly doubled on Jan. 9, occurring every three to 20 seconds. From Jan. 9-14, the eruption stabilized, with a few explosions per minute.

The volcano on Anatahan first erupted after centuries of dormancy on May 10, 2003, with ash plume rising to an altitude of over 30,000 feet that covered over 1 million square kms of airspace above the Pacific Ocean and reached Philippine jurisdiction. That eruption, which ceased by mid-June that year, deposited about 10 million cubic meters of material over Anatahan island and the sea.

The second series 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.

Anatahan remains off-limits to the public, except for government and approved scientific missions, pursuant to a continuing emergency declaration by Gov. Juan N. Babauta.

VOLCANIC HAZE ALERT STILL IN EFFECT

Camacho said the volcanic ash and haze alert for Saipan and Tinian still stands, with north winds expected to continue to bring suspended volcanic dust and possibly sulfur from the volcano.

Report from the National Weather Service on Tiyan, Guam indicated that volcanic haze would be present early yesterday evening.

EMO said the volcanic particles, brought to the southern islands of the Commonwealth because of a change in wind direction brought by Tropical Storm Kulap, may appear like a thin haze or mist over the sky and can cause breathing difficulties.

The public is urged to take precaution due to the ashfall to avoid health-related problems.

Those with respiratory ailments, such as asthma, as well as infants and elders are encouraged to avoid prolonged outdoor activities.

The public is urged to refrain from drinking water collected from rain, which may be contaminated. Water tanks should be covered and roof collection systems turn off.

HIGH SURF

Also, high surf and small craft advisory remains in effect for Saipan, Tinian, and Rota.

Forecast for today features northeast winds 15 to 20 knots with gust of up to 30 knots and wind waves of 5 to 7 feet and northwest swells of 8 to 10 feet.

Beachgoers, surfers, swimmers, fishermen, and marine tour operators are urged to avoid venturing to exposed areas to avoid injuries or even death.

The waters have already claimed one life this year, when a tourist drowned off Hidden Beach earlier in the month.