Bulusan Volcano growls anew after short lull

By Cet Dematera

Bulusan Volcano in Sorsogon had acted up again on Tuesday, June 21, after its volcanic earthquakes shot up 80 times in the past 24 hours monitoring period, from merely seven times in the last three days, Philippine Institute of Volcanology and Seismology (Phivolcs) data showed.

Phivolcs said that from only one quake on June 20, six on Jume 19 and five on June 18, Bulusan’s seismic activities resumed again to two digits, even accompanied by a volcanic tremor.

Bulusan’s emissions continued to fluctuate between 800 and 1,200 meters above the main crater and vents, with plumes ranging from 100 to 200 meters drifted west-south-west, while its ground remains inflated in the past three days.

Phivolcs said that the increasing seismicity could lead to sudden and hazardous phreatic eruptions.

“Most were weak and shallow events, but may indicate that a phreatic eruption could possibly occur within the next few hours to next few days,” Phivolcs warned.

Gerald Malipot, Phivolcs Volcano Monitoring Division duty-officer, said that Bulusan could erupt ash anytime under alert level one.

This seismic activity and other abnormal signs mean that degassing is continuing inside the volcano, including the possible ascent of new volcanic materials, Malipot said.

“We really need to be vigilant against a sudden phreatic eruption over Bulusan anytime. Even the sudden drop in the number of volcanic earthquakes is not a guarantee that eruption is remote already. Alert level one means the volcano is abnormal,”Malipot said.

Phivolcs continues to remind the public not to enter the four-kilometer radius Permanent Danger Zone (PDZ) due to the increased possibilities of sudden and hazardous phreatic eruptions.

The agency said that civil aviation authorities must also advise pilots to avoid flying close to the volcano’s summit as ash from any sudden phreatic eruption can be hazardous to aircraft.

“People living within valleys and along river/stream channels especially on the southeast, southwest and northwest sector of the edifice should be vigilant against sediment-laden stream flows and lahars in the event of heavy and prolonged rainfall should phreatic eruption occur,” Phivolcs added.

Some 500 persons moved to evacuation centers in Juban when Bulusan erupted ashes on June 5 and June 12.

Bulusan Volcano