Mt. Bulusan abnormal signs drop in past week

By Cet Dematera

After registering over 20 volcanic earthquakes seven days ago, Bulusan Volcano’s seismic events dropped again, while its sulfur dioxide (SO2) emissions remained high and fluctuated between 400 and 1,200 tons, respectively, in the last six days, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

Phivolcs data showed that from 21 on July 6, Bulusan’s volcanic quakes dropped to 11 on July 7, then dived down to three on July 8, inched up to five on July 9, six on July 10, then dropped again to two on July 11, then three on Tuesday, July 12.

While Bulusan’s seismic activity was observed to be in the downward trend in the past days, SO2 emissions fluctuated between 400 and 1,200 tons in the past seven days.

Renato Solidum, Phivolcs officer-in-charge, said that despite the continuing drop in volcanic quakes, alert level 1 will stay as long as the other abnormal signs are present.

“We cannot lower yet Bulusan’s alert 1 because SO2 and plume emissions are still high. Besides its surface is still inflated,” Solidum told Bikol Mail.

He also warns that phreatic eruptions are possible at any time under alert level 1.

Solidum said they have to wait until all other abnormal parameters also proceed to downward trends.

“We still have to observe for weeks or months before we could tell that Bulusan is already going to normal,” he added.

Solidum reminded the public to keep out of the four-kilometer radius Permanent Danger Zone (PDZ), and the two-kilometer Extended Danger Zone (EDZ).

He also advised people living within valleys and along rivers or stream channels, especially on the southeast, southwest and northwest sector of the edifice, should be vigilant against sediment-laden stream flows and lahars.

Bulusan was placed under alert level one, or abnormal condition after its phreatic eruption on June 5.