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Magnitude 5.8 Quake Strikes Off Mindanao Amid Week of Strong Tremors

A magnitude 5.8 earthquake struck off Surigao del Sur on Oct. 29, part of a burst of strong quakes around Mindanao that led Sarangani to suspend classes.

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Photo: Judgefloro, Wikimedia Commons, Public domain (file photo of the PHIVOLCS building in Quezon City).

A magnitude 5.8 earthquake struck off the eastern coast of Mindanao in the southern Philippines on Thursday, Oct. 29, 2026, at 11:19 a.m. local time (03:19 UTC; 11:19 p.m. ET Wednesday), according to the U.S. Geological Survey. The Mindanao earthquake was centered about 110 kilometers (68 miles) east-northeast of the town of Barcelona, Surigao del Sur, at a shallow depth of about 10 kilometers.

M5.8
USGS magnitude, Oct. 29
Mw5.9
PHIVOLCS magnitude
19
quakes of M4.5+ in the region, Oct. 26-29 (USGS)
Green
USGS PAGER alert level

What the agencies measured

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) put the quake at magnitude 5.9 and located it offshore of Lingig, Surigao del Sur, in its earthquake bulletin. Unverified claim, PHIVOLCS (Government of the Philippines (Department of Science and Technology)) Small differences in magnitude between agencies are common in the first hours after a quake.

The USGS issued a green alert under its PAGER system, meaning it estimates a low likelihood of casualties or significant damage.

By the numbers: a busy week of shaking

Largest Mindanao-area quakes, Oct. 26-29Magnitude, USGSMagnitudeOff Surigao del Sur (Oct. 29)5.8Near Barcelona (1)5.4Near Barcelona (2)5.4Balut Island area5.2Balut Island area (2)5.1Sarangani4.8
Source: USGS; chart: The Boston Report

A search of the USGS earthquake catalog by The Boston Report found 19 earthquakes of magnitude 4.5 or greater in the region around Mindanao and eastern Indonesia from Oct. 26 to 29. Those include two magnitude 5.4 quakes near Barcelona, a magnitude 5.2 and a 5.1 near Balangonan on Balut Island in Sarangani province, and a magnitude 4.8 in Sarangani. Farther afield, the USGS recorded a magnitude 5.7 about 271 km west-southwest of Tual in Indonesia’s Maluku islands, a 5.4 south of Pundong on Java and a 5.3 near Tobelo in North Maluku.

The region sits where several tectonic plates converge, including along the Philippine Trench off eastern Mindanao, and moderate earthquakes are frequent.

Sarangani suspends classes

In Sarangani province, authorities suspended classes and government work on Wednesday, Oct. 28, after a magnitude 5.1 quake struck at 7:43 a.m. near Balut Island, GMA News reported.

The Sarangani shaking is part of an aftershock sequence from the magnitude 7.8 earthquake that hit the area on June 8, 2026, the Philippine Daily Inquirer reported. Large earthquakes can produce aftershocks for months, with their frequency generally declining over time.

What residents are advised to do

PHIVOLCS advises residents to “drop, cover and hold” during shaking, to stay away from damaged structures and to follow local disaster officials.

The Philippines sits on the Pacific “Ring of Fire” and records thousands of earthquakes a year, most too small to be felt. For more coverage of the Philippines and its neighbors, visit our Southeast Asia news hub, including our report on the defense ministers’ meetings in Cebu.

Background: the June 8 Sarangani earthquake

The magnitude 7.8 earthquake that struck near Sarangani on June 8, 2026, was the strongest to hit Mindanao in years, and its aftershocks have continued for nearly five months. Aftershock rates typically fall off over time, but a large mainshock can still produce occasional magnitude 5 or larger events many months later, according to USGS guidance on aftershock forecasts.

Mindanao’s east coast faces the Philippine Trench, where the Philippine Sea Plate dives beneath the Philippine Mobile Belt. That subduction zone produced a magnitude 7.4 earthquake off Hinatuan, Surigao del Sur, in December 2023, which triggered tsunami warnings in the Philippines and Japan. Thursday’s quake was in the same general offshore area, though much smaller.

Southern Mindanao around Sarangani and Davao Occidental sits near the Cotabato Trench and the Molucca Sea collision zone, a complex area also responsible for frequent earthquakes in North Maluku and Sulawesi in Indonesia.

A magnitude 5.8 quake releases roughly one-thousandth of the energy of a magnitude 7.8, because each whole-number step on the magnitude scale represents about 32 times more energy. Damage from moderate quakes depends heavily on depth, distance from towns and building quality. PHIVOLCS posts bulletins for each event on its website, and the USGS maintains a searchable catalog with maps. Residents can also report felt shaking to the USGS “Did You Feel It?” service, which helps scientists map intensity.

Related coverage: Philippine peso breaks past 64 per dollar. China downgrades its ADMM-Plus delegation. Find all of our regional reporting, plus country facts and official resources, on the Southeast Asia news hub.

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