Movement in Cotabato fault system triggered recent quakes in Mindanao —PHIVOLCS

PHIVOLCS director Renato Solidum said Friday the movement in the Cotabato fault system caused the series of earthquakes and aftershocks that shook parts of the southern Philippine island of Mindanao in the past weeks.

“Dito sa Cotabato province, may tinatawag na Cotabato fault system. ‘Yung ilang bahagi nito o branches o sanga ay kumikilos,” Solidum told GMA News TV’s Balitanghali.

“Nagsimula pa nga ito nung October 16 and even before na nagdulot ng magnitude 6.3 nung gabi ng October 16, na-trigger niya ‘yung magnitude-6.6 sa isang kaparehong lugar at kahapon nagkaroon ng  pagkilos mas north ng dating episentro dun sa Cotabato area din, magnitude 6.5,” he said.

He said the aftershocks experienced will continue to be felt by the residents in the coming days or weeks as a result of the movement and adjustment of the fault in the system.

“Ang sinasabi natin ay nagkakaroon ng aftershocks at nag-aadjust pa ang kapaligiran dahil sa pagkilos ng malakihang fault na ‘yan at kadalasan sa serye ng mga paglindol ay nagtatagal ng mga araw o linggo ang mga sumusunod na aftershock,” he said.

He said they are monitoring the Cotabato fault system for other movements.

According to a primer published by PHIVOLCS on its website, Central Mindanao (SOCCSKSARGEN Region), which includes Cotabato, is one of the seismically active regions in the country because of the presence of several active faults in the area which include the M’lang Fault, Makilala-Malungon Fault, North Columbio Fault, South Columbio Fault, and the western extension of the Mindanao Fault (Cotabato-Sindangan Fault).

It said the Cotabato Trench is also a major source of earthquakes which can affect the region. It added there are other nearby local faults, some of which may be covered by recent deposits, and could be sources of small to strong magnitude earthquakes. — Amita Legaspi/MDM, GMA News