7.8-magnitude quake off southern Mindanao damages buildings, triggers tsunami warnings

A powerful offshore earthquake struck off southern Mindanao early Monday, damaging buildings in and around General Santos City, disrupting basic services and prompting tsunami warnings and coastal evacuations in the Philippines and parts of Indonesia. Police in General Santos, quoted by AFP, said at least one person was killed and four others were injured in an early local account as rescue and damage checks continued.

The quake hit at 7:37 a.m. local time Monday, or 23:37:43 UTC Sunday, according to the Pacific Tsunami Warning Center and Philippine authorities. The magnitude 7.8 temblor was centered offshore southern Mindanao, off Maasim in Sarangani province, southwest of General Santos City. Philippine seismologists reported very strong shaking in General Santos, including Intensity VII in local reporting.

Early reports from Philippine officials and wire services said the quake damaged buildings in General Santos, including at least one small building collapse or structure with major damage. Power, internet and water services were also disrupted in parts of Mindanao after the shaking. Schools and some local government offices suspended classes and work to allow safety inspections.

The casualty count remained preliminary. General Santos police, cited by AFP, said one person had been killed and four others injured, but broader national confirmation was still pending. “Many buildings were affected, but I cannot enumerate them now because we are busy with ongoing rescues,” Master Sgt. Robert Dagon of the General Santos police told AFP.

Tsunami warnings and advisories were issued after the quake, triggering evacuations along vulnerable coastlines in the southern Philippines and in parts of Indonesia, according to the tsunami warning center and Reuters. The warning center later reported small tsunami heights on coastal gauges, including about 0.8 meters at Talengen in Sulawesi and 0.5 meters at Davao, indicating the quake produced measurable sea-level changes. Shaking was also reported in Indonesia’s North Sulawesi and North Maluku. Multiple aftershocks followed.

President Ferdinand Marcos Jr. said the national government was coordinating the response and urged residents in vulnerable coastal areas to move to higher ground. The Department of Social Welfare and Development said it was mobilizing assistance. Teresito Bacolcol, director of the Philippine Institute of Volcanology and Seismology, or PHIVOLCS, said: “We advise people to evacuate to higher grounds or go further inland.”

The urgency of the tsunami response reflected the region’s geology and history. Southern Philippines lies along an active subduction zone linked to the Cotabato and Celebes trench system, where one tectonic plate is forced beneath another and can generate powerful offshore quakes. The same broad region was struck by the 1976 Moro Gulf earthquake and tsunami, a disaster that killed thousands and remains a potent reminder of why coastal evacuation orders are taken seriously.