Aftershocks expected in Davao de Oro, says PHIVOLCS

DAVAO CITY (MindaNews / 8 March)—Residents in earthquake-affected areas in Davao de Oro and neighboring areas may continue to experience aftershocks lasting for several days to weeks, according to the Philippine Institute of Volcanology and Seismology (PHIVOLCS).

March 7, 2023 magnitude 5.9 Davao de Oro quake and aftershocks. Illustration courtesy of PHIVOLCS. Click here for more on PHIVOLCS’s update on the Davao de Oro quake.

In an information released on Wednesday, the PHIVOLCS said that the aftershocks are expected and “occurrences of strong earthquakes are not discounted” after a series of tremors occurred with epicenters in Davao de Oro.

As posted in the PHIVOLCS website as of 5:13 p.m. Wednesday, 122 aftershocks have been recorded in Davao de Oro and neighboring provinces since the magnitude 5.9 quake at 2:02 p.m. Tuesday.

The agency warned residents that seismic hazards— such as landslides, rock falls, and liquefaction—may happen after the occurrence of strong earthquake.

Shortly after Tuesday’s earthquake, Governor Dorothy Montejo-Gonzaga ordered anew the suspension of work and classes in all levels for both public and private schools.

Davao del Norte Governor Edwin Jubahib likewise suspended work and classes in the province from March 7 to March 8 to ensure the safety and well-being of students, employees, and residents.

“The earthquake, which was felt across several parts of the Davao Region, has caused damage to some buildings and infrastructure. The authorities are assessing the situation and ensuring that appropriate measures are taken to safeguard the public,” he said.

Last Monday, a series of strong earthquakes ranging from Magnitude 4.9 to 5.3 rocked Davao and its neighboring regions.

PHIVOLCS said the recent earthquakes are inland, allaying fears that tsunamis might occur.

It added that “tsunamis are often produced by earthquakes generated by active trenches, offshore faults with significant vertical movements, or mass movement related to earthquake-induced landslides near bodies of water.”

It said, however, that there might be localized sea-level disturbances as a result of extreme ground shaking resonating along bays.

The PHIVOLCS said it is operating a sea-level monitoring station in Mati, Davao Oriental as part of the local tsunami warning system.

“In case of another strongly felt earthquake, it is recommended that people protect themselves by doing the ‘drop, cover, and hold’ [procedure],” it said. This refers to dropping to one’s hand and knees in case of earthquakes; cover the head, neck, and entire body if possible; and holding on to something sturdy until the shaking stops.

It advised residents that “heavy furniture and appliances should be strapped to the walls, and hanging objects securely fastened to prevent these from causing injuries.”

“People should be cautious of structures visibly weakened or having signs of damage caused by the series of earthquakes as these may further damage the structures and injure the building occupants,” it said.

Structurally compromised buildings should not be reoccupied unless certified safe by structural engineers, according to PHIVOLCS.

The agency said that Davao de Oro is “one of the seismically active regions in the country” because of the presence of active faults that include the East Compostela Valley, West Compostela Valley, Central Compostela Valley, Nabunturan, Caraga River, and Mati Segments of the Philippine Fault, and the Central Mindanao Fault.

It noted that at least 11 “strong to great earthquakes” with magnitude ranging from 6.0 to 8.3 occurred in the province and its vicinity since 1891. “The most damaging earthquake that affected Davao de Oro was the 21 June 1893 M7.3 Monkayo earthquake … along the Philippine Fault which produced numerous landslides, liquefaction, and structural damages.” (Antonio L. Colina IV / MindaNews)