Flag-raising ceremonies were underway across Sarangani when the ground gave way beneath southern Mindanao on Monday morning. Benjie Ancheta, police chief of Alabel town, said the police building developed cracks immediately after the quake hit during the ceremony. “This is the strongest earthquake we’ve experienced,” Ancheta told Reuters by phone, noting that some people fainted though no casualties were initially confirmed in his area.
The United States Geological Survey logged the tremor at magnitude 7.8, striking around 7:37 a.m. local time at a depth of roughly 35 kilometers off the shores of General Santos City in Sarangani, the southernmost point of Mindanao. The agency placed the epicenter about 26 kilometers southwest of Kablalan in the province. Estimates varied as agencies scrambled to confirm the scale: the German Research Centre for Geosciences had earlier pegged it at 8.2, Indonesia’s BMKG measured 7.7, and the Philippine Institute of Volcanology and Seismology (Phivolcs) initially put it at 7.0.
Phivolcs ordered coastal residents across at least nine Mindanao provinces to move inland without delay. The US Tsunami Warning System projected waves of one to three meters above tide level along parts of the Philippine coast. Warnings extended beyond the country’s borders, reaching Indonesia’s northeastern coast and prompting a tsunami advisory for Japan’s southern shoreline from Ibaraki to Okinawa. Indonesia’s geophysics agency later reported detecting waves of just under 0.2 meters.
Damage surfaced quickly in the urban centers nearest the fault. Images released by the local information office in General Santos showed convenience stores and other buildings collapsing in the moments after the shaking. A DZBB radio crew broadcasting from the city, about 15 kilometers from the epicenter, described furniture toppling and appliances breaking as aftershocks rolled through and residents fled their homes. In Koronadal City, where the tremor lasted around 30 seconds, internet, electricity, and water services went down across several districts.
The disaster landed on an awkward date for families: the first day of the school year in many areas. President Ferdinand Marcos Jr. suspended classes at all levels across affected parts of Mindanao until further notice and said the Office of Civil Defense and the National Disaster Risk Reduction and Management Council were coordinating the response. He directed the social welfare department to preposition relief goods and ready evacuation centers, with the public works department on standby to inspect roads, bridges, and other infrastructure. “The national government is moving and we will not leave Mindanao behind,” Marcos said in a statement.
Phivolcs recorded Instrumental Intensity VIII in Malapatan, Sarangani — its second-highest reading — and Intensity VII in Koronadal, South Cotabato, and Santa Maria, Davao Occidental. A first aftershock followed at 7:49 a.m. The agency warned that further damage and aftershocks were likely as response teams continued assessing the situation.
