Davao City's earthquake faults too far for stress transfer

Friday, December 20, 2019 12:30 AM    Views : 42by:Rudolph Ian Alama

Phivolcs OIC Renato Solidum explains to the media the series of quakes that hit the region.

DAVAO CITY (PIA) - The Philippine Institute of Volcanology and Seismology (Phivolcs) said that the Davao Central Fault System in Davao City is far from the current active faults in Davao del Sur and North Cotabato from where stress can be transferred.

“Malayo na po ang faults doon para talaga ma-impluwensiyahan, (The faults there are too far to be influenced),” says Phivolcs OIC USec. Renato Solidum during a press conference held in Digos City on December 18.

Solidum said the quakes and aftershocks which severely hit Davao del Sur and North Cotabato on October 16, 29, 31 and recently December 15 were caused by crustal stress transfer.

“Nung gumalaw siya (fault) nagtrigger na siya ng 6.3 na lindol nung October 16,nailipat nya ang stress na tinatawag nating crustal stress transfer sa kapitbahay ng mga bato at nagdulot ng 6.6 at gumalaw ito at nagdulot ng lindol sa Makilala fault na magnitude 6.5 (When it moved (the fault),  it triggered a 6.3 earthquake in October 16, it transferred the stress which we call crustal stress transfer to neighboring rocks and it caused 6.6 quake and the other faults moved which caused the quake in Makilala with a magnitude 6.5),” Solidum explained the series of faults.

However despite the Davao del Sur and North Cotabato faults being far from the faults in Davao City as to influence its movements, Solidum warned that the faults in Davao City has the possibility to move independently and not rely on other neighboring faults.

Solidum said that Southern Mindanao is being pressured on three sides, from the eastern side the Pacific Ocean/Philippine Sea is pressing to the west, the Celebes Sea in the west is pushing to the east and the Indonesian islands is pushing up. The three sided pressure can help the faults to move.

He said that the faults in Davao City have been producing minor earthquakes in recent years.

“Do you remember in 2017, there was an earthquake in Davao City where a waiting shed collapsed? One of the faults in Davao City moved,” Solidum recalled.

The Phivolcs chief was referring to the February 23, 2017 quake which had a magnitude of 4.6, with the epicenter located 9 kilometer southwest of Davao City. The quake injured two persons after a waiting shed collapsed upon them.

He said that unlike Luzon and Visayas, the island of Mindanao has several neighboring faults which is brought about by being pressured from three sides.

Solidum said the  pressure created the island of Samal and limestone high grounds in the region, it also created the numerous faults.

Solidum together with the Phivolcs team are currently going around the local governments in Davao del Sur to help spread awareness and correct information about the series of quakes in the area.

The December 15 6.9 earthquake with the epicenter in Matanao, Davao del Sur has claimed the lives of eight people and destroyed thousands of structures.

“Rather than being scared, we should always prepare and be ready,” Solidum said. (PIA/RG Alama)


S & T Trivia

" The Filipino doctor who co-created the drug Erythromycin (Ilosone®) from Iloilo soil was Abelardo Aguilar. "

Online Resources
© copyright 2012 All rights reserved.