DAVAO CITY, Davao del Sur, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) has advised the public in the quake-hit areas of Mindanao to brace for more tremors.
The agency said Tuesday’s devastating earthquake in Tulunan, Cotabato province, was a continuation of events from interrelated active faults in Central Mindanao.
“We expect small- to moderate-magnitude earthquakes to occur in the epicentral area which may continue for several days to weeks, some of which may be felt,” Phivolcs said in a primer it made public a day after the powerful 6.6-magnitude earthquake that was centered near Tulunan.
Phivolcs explained that the tremor was part of a series of quakes in central Mindanao, which included the 5.6-magnitude quake that struck Makilala, Cotabato, on July 9 and the Oct. 16 6.3-magnitude temblor also near Tulunan.
Tuesday’s temblor jolted the region, leaving at least seven people dead and scores wounded, and many buildings and structures destroyed or damaged.
Three people were reported to have been buried in a landslide in Magsaysay, Davao del Sur province, and four others went missing, also in a landslide, in Makilala, Cotabato.
Digos state of calamity
Digos City, one of the hardest hit areas, declared a state of calamity on Wednesday. It was still recovering from the Oct. 16 quake.
Gil Gubat, a disaster management officer of the city, placed major damage to some structures at P238 million, and minor damage to others at P20 million.
One of the Cor Jesu College buildings has been deemed unfit for occupancy.
Gubat said a more thorough damage assessment could not yet be undertaken because of the danger posed by aftershocks.
City information officer Nikkolo Marco Cortes said scores of houses were destroyed in several villages.
Mass evacuations
Shopping malls and department stores that had reopened after repairs following the Oct. 16 quake were ordered closed by the city government, threatening the livelihood of hundreds of workers.
About 860 families in Magsaysay and more than 1,000 residents of Kidapawan City have been evacuated.
Landslides blocked many roads, including one that cut off Barangay Bacong to the Tulunan center.
Many business establishments in Kidapawan were closed, some for safety reasons and others due to the absence of workers.
The National Disaster Risk Reduction and Management Council (NDRRMC) on Wednesday reported that more than 130 structures, mostly schools, had been damaged by Tuesday’s quake.
At least 94 schools, 11 health facilities, and 28 other private and public establishments were damaged on the Zamboanga Peninsula and in Northern Mindanao, the Davao region, Soccsksargen and the Bangsamoro Autonomous Region in Muslim Mindanao, it said.
The NDRRMC said 48 schools were damaged in Soccsksargen, many in the provinces of Sultan Kudarat, Cotabato and South Cotabato, where buildings were cracked.
The ceiling of Nueva Vida National High School in M’lang town collapsed, it said.
In Davao region, 35 schools, mostly in Davao del Sur, were damaged. Barangay Altavista day care center in Bansalan, Davao del Sur, was destroyed.
200 schools damaged
By its own count, the Department of Education (DepEd) on Wednesday said 200 schools suffered either major or minor damage.
It said 185 classrooms were destroyed and 1,066 had major or minor damage.
Education Undersecretary for Finance Annalyn Sevilla said her office had asked the Department of Budget and Management for more funding to its quick response fund (QRF), which is earmarked for the repair and replacement of classrooms destroyed or damaged during calamities.
Sevilla said the QRF had already been depleted by allocations made to damaged schools in the first half of 2019.
Reconstruction and rehabilitation of the school buildings and classrooms would cost about P363 million, she said.
Aside from the QRF, Sevilla said “there is also DRRMS (disaster risk reduction and management services) operational fund within the DepEd 2019 budget and this is what we use for cleanup, temporary learning space and other minor repairs.”
Active faults
The Phivolcs primer said at least 874 aftershocks were recorded between the Oct. 16 and Oct. 29 quakes. Since Tuesday’s quake, 237 more aftershocks were noted, the strongest, a 6.1-magnitude, was recorded less than two hours after the 9:04 a.m. tremor.
The aftershocks coming from the Tulunan and Makilala source areas might not be stronger than Tuesday’s tremor, but one that is more powerful than Tuesday’s temblor and emanating from another source “cannot be discounted,” it said.
According to Phivolcs, Central Mindanao “is one of the seismically active regions in the country because of the presence of several active faults in the area.” These 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).
The Cotabato Trench is a potential source of earthquakes along with local faults.
Tsunami ruled out
Phivolcs dispelled fears, mostly caused by misleading posts on social media, that the quake incidents could generate a tsunami, pointing out the inland epicenter of the tremors.
“Although the nearest active volcanoes from the epicenter are Matutum volcano and Parker volcano, the 6.6-magnitude event and succeeding earthquakes are tectonic in origin,” Phivolcs added.
It warned that the recent seismic activities could cause deadly landslides, rockfalls and other types of mass movements in mountainous or hilly areas, or liquefaction in low-lying, water-saturated and sandy areas near riverbanks and shorelines.
Phivolcs appealed to the public to remain vigilant and be always prepared in case of another strong earthquake. —With reports from Jeannette I. Andrade, Matthew Reysio-Cruz, Abner Francisco and Eldie S. Aguirre