Strong Magnitude 5.5 Aftershock Rattles Balut Island, Shakes Parts of Southern Mindanao

Courtesy: PHIVOLCS

A strong offshore magnitude 5.5 earthquake jolted the waters near Balut Island in the municipality of Sarangani, Davao Occidental, in the early hours of Saturday, July 18, 2026.

The state-run Philippine Institute of Volcanology and Seismology (PHIVOLCS) logged the seismic event at exactly 12:12 a.m.. The tremor, which was tectonic in origin, occurred at a shallow depth of 10 kilometers. Its epicenter was located approximately 8 kilometers northwest of Balut Island.

Regional Shaking and Felt Intensities

Despite the epicenter being situated offshore, the shallow nature of the quake caused distinct ground shaking across several provinces in Southern Mindanao. Residents in urban areas reported being awakened by the midnight tremor.

PHIVOLCS recorded the following intensities:

• Intensity IV - CITY OF GENERAL SANTOS; Malapatan and Glan, SARANGANI; Tupi, SOUTH COTABATO
• Intensity III - Kiamba and Maasim, SARANGANI

Instrumental Intensities:

• Intensity IV - CITY OF GENERAL SANTOS; Tupi, SOUTH COTABATO
• Intensity III - Malungon, SARANGANI; Palimbang, SULTAN KUDARAT
• Intensity II - City of Kidapawan, COTABATO; City of Digos, DAVAO DEL SUR; Kiamba, SARANGANI; Magsaysay, DAVAO DEL SUR; Sta. Maria, DAVAO OCCIDENTAL; T'Boli and Tampakan, SOUTH COTABATO
• Intensity I - Banga and Surallah, SOUTH COTABATO; Kalamansig, Lebak, and Isulan, SULTAN KUDARAT; Malapatan and Maitum, SARANGANI

Aftershock of Major June 2026 Quakes

Seismologists clarified that the Saturday midnight tremor was not an isolated event. It was a direct aftershock of the catastrophic magnitude 7.8 Offshore Sarangani and magnitude 6.5 Offshore Davao Occidental earthquakes that devastated portions of the region in June 2026.

The major June disaster previously placed the province under a state of calamity, resulting in significant structural damage, displacement, and casualties across coastal communities. Since then, the sub-surface faults along the Cotabato Trench and adjacent offshore fissures have remained highly active, producing an ongoing sequence of moderate-to-strong adjustments.

Current Situation and Safety Reminders

As of Saturday morning, local disaster risk reduction and management offices (DRRMOs) in Davao Occidental and neighbouring SOCCSKSARGEN areas have reported no new casualties or immediate structural infrastructure damage resulting from this specific event.

However, emergency response teams remain on high alert. PHIVOLCS maintains that subsequent aftershocks are still expected in the coming days. Local authorities continue to remind the public to stay calm but vigilant, inspect homes for any new fractures, and familiarize themselves with local evacuation routes.