Phivolcs Misses Key Earthquake Data, Seismic Instrument Stolen Last Year

By Juan Escandor Jr. (Inquirer)
Posted 03:27am (Mla time) June 21, 2006

SORSOGON CITY—The Philippine Institute of Volcanology and Seismology (Phivolcs) could have a made a more accurate forecast of Mt. Bulusan’s volcanic activity were its data complete. But one of its seismic instruments, planted on the upper slope of the volcano, was stolen in August last year, said a Phivolcs specialist.

Eduardo P. Laguardia, Bicol volcano monitoring coordinator, said yesterday that the stolen seismic instrument might have made a difference because it records localized tremors near the crater that could not be detected in other parts of the volcano.

He said the data from the stolen gadget could have helped Phivolcs make a more accurate forecast before Bulusan spewed ash on March 21.

Laguardia said they had to employ alternative means to fill in the data gap. For example, they supplemented the data taken from their seismic instruments with gas measurements to come up with a more accurate forecast.

The Philippine Air Force (PAF) said evacuation was urgent.

“It’s important that the residents heed the government’s advice to evacuate. Conducting an aerial rescue mission if there’s an ash fall would be extremely difficult and risky,” Maj. Augusto dela Pena, PAF spokesperson, told the Inquirer in a phone interview.

De la Pena said that an Air Force rescue should be the “last resort” in case a major eruption takes place.

“If there would be any rescue missions, it would be for isolated cases already,” De la Pena said.

Army troopers have helped evacuate some 450 residents after Mt. Bulusan spewed ash and gravel over the weekend.

Another 100 villagers living near the slopes of the volcano have evacuated to a nearby high school but most of the men stayed behind to guard their homes, Mayor Edwin Hamor of nearby Casiguran town had said.

On Monday, authorities estimated more than 20,000 people face evacuation in case of a major eruption, and set out plans for erecting tent cities outside a 6-km radius of the volcano.

De la Pena said that two Air Force UH-1H Huey helicopters have been placed on standby in Legazpi City since last week.

The Air Force has also flown scientists from the Phivolcs for aerial surveys of Bulusan last Monday, the PAF spokesperson added.