Fault movements, not volcanoes, caused Mindanao quakes: Phivolcs

“Say a volcano is to erupt, there has to be swelling of ground surface or noticeable steaming. So far, wala namang reports on that (So far, there are no reports on those yet),” said Department of Science and Technology Undersecretary for Disaster Risk Reduction and Climate Change and Phivolcs, OIC Renato Solidum Jr. in a phone interview. (PNA file photo)

MANILA — There is no basis to rumors that the series of quakes felt in parts of Mindanao were caused by any volcanic activities, an official of the Philippine Institute of Volcanology and Seismology (Phivolcs) said on Thursday.

“Say a volcano is to erupt, there has to be swelling of ground surface or noticeable steaming. So far, wala namang reports on that (So far, there are no reports on those yet),” said Department of Science and Technology Undersecretary for Disaster Risk Reduction and Climate Change and Phivolcs, OIC Renato Solidum Jr. in a phone interview.

The series of strong quakes caused speculation online that the country’s highest peak, Mount Apo, might erupt again.

There are no reports of any volcanic activity in Mount Apo that sits across Davao City and Davao del Sur province and Cotabato, Solidum said.

Fault movement, not volcanic activity

A 6.5-magnitude tremor struck at 9:11 a.m. on Thursday (October 31), two days after a magnitude 6.6 earthquake, with the epicenter in Tulunan, North Cotabato.

On October 16, a 6.3-magnitude tremor also rocked many parts of Mindanao, leaving left seven persons dead.

In a separate interview, Phivolcs Science Research specialist Erlinton Olavere said the faults may have reacted from the recent movements of the other faults.

“Gumalaw ang isang fault, then nagre-react din ang isang fault. Kaya ang area, mapapansin natin malalakas na (lindol). Magnitude 6.6, then we have magnitude 6.1, then we have a 6.5 today. Two weeks before nagkaroon din tayo ng 6.3. Interrelated (A fault moved then another reacted.

That’s why the shakes are getting stronger. We had a 6.6 then a 6.1, and today, we experienced a 6.5 just two weeks ago there was also a 6.3, the quakes are interrelated),” Olavere said.

Monitoring active volcanoes

While the agency is now studying the movement of the faults in the area, they are also closely monitoring the nearest active volcanoes from the epicenter of Tulunan– Matutum and Parker.

“Would the earthquakes trigger an eruption? Possibly. It can trigger if there is magma. But there are no reports of heat changes. We are monitoring the active volcanoes near the epicenter,” Solidum said.

The study is part of DOST-Phivolcs monitoring procedures for moderate to strong earthquakes occurring near active volcanoes.