'Mayon's eruption won't be as explosive as Pinatubo's'


Posted at Dec 22 2009 04:45 PM | Updated as of Dec 23 2009 12:45 AM

MANILA, Philippines - Mayon Volcano's imminent eruption will not be as explosive as the June 1991 explosion of Mount Pinatubo, a geologist said Tuesday.

"Based on historical records, the eruption of Mayon has been characterized as small volumes of eruption. Mayon erupts much smaller volumes than Pinatubo," Mahar Lagmay of the University of the Philippines' National Institute of Geological Sciences told ANC's Dateline Philippines.

Lagmay said the biggest eruption of Mayon was in 1814, releasing several hundreds of millions of cubic meters of volcanic debris. He said the eruption was way smaller compared to Mount Pinatubo's eruption of 11 billion cubic meters in 1991.

He added that Mayon Volcano's highest pyroclastic eruption was 15 to 16 kilometers column high, which is only half of Pinatubo's more than 30-kilometer column high eruption.

Lagmay, meanwhile, said that despite the decline in the number of volcanic earthquakes detected from Mayon Volcano since Monday night, there was still the possibility of a hazardous eruption anytime.

In its 7 a.m. Tuesday bulletin, the Philippine Institute of Volcanology and Seismology (Phivolcs) said Mayon Volcano "continued to show an intense level of activity during the past 24 hours."

It said a total of 1,266 volcanic earthquakes were detected during the 24-hour observation time, which is lower compared to Monday's 1,942.

The Phivolcs said that despite the decrease, the volcano remains very restive because volcanic earthquakes have become more intense.

"Many of these volcanic earthquakes were recorded at maximum deflection and have continuously occurred since 12:21 p.m., 20 December 2009 (Sunday). Harmonic tremors were still continuously being recorded," the Phivolcs bulletin said.

The bulletin added that the volcano's sulfur dioxide emission rate remained "very high," measuring an average of 6,529 tons per day.