Three fault lines beneath Isabela could trigger powerful 7.2 Quake, says Phivolcs

ISABELA, Philippines – Isabela and nearby areas could experience an earthquake as strong as magnitude 7.2 if any of the province's three active fault lines move, according to the Philippine Institute of Volcanology and Seismology (Phivolcs) Cagayan Valley.

The warning comes amid heightened public awareness of earthquakes following the powerful magnitude 7.8 earthquake that struck Mindanao on June 8, the opening day of classes. The quake affected Sarangani and neighboring provinces and had claimed at least 42 lives as of June 11.

Located within the Pacific Ring of Fire, the Philippines is highly vulnerable to earthquakes and volcanic activity due to the movement of tectonic plates beneath the country.

With continued seismic activity being monitored nationwide, Phivolcs has reminded communities situated near active fault lines to remain vigilant and prepared.

What are active fault lines?

Active fault lines are fractures in the Earth's crust where movement has occurred in recent geological history and may occur again in the future. When these faults move, they release energy that can generate earthquakes, ranging from minor tremors to destructive seismic events.

In Isabela, Phivolcs has identified three active fault lines that have the potential to produce significant earthquakes.

One of these is the Divilacan Fault, which was responsible for the magnitude 5.8 earthquake that struck the province in May 2023.

According to Engr. Shally Marck Daguiao, Science Research Assistant of Phivolcs Cagayan Valley, the Divilacan Fault is capable of generating an earthquake of up to magnitude 7.2.

Phivolcs also identified another active but unnamed fault in Ilagan City, which triggered the magnitude 3.4 earthquake recorded on June 3, 2026.

Meanwhile, the Santiago Segment, which is connected to the East Cordillera Fault and was linked to the series of earthquakes felt in June 2025, could likewise generate a magnitude 7.2 earthquake.

Stay prepared

Since no existing technology can accurately predict the exact date and time of an earthquake, Phivolcs continues to urge residents living near fault lines to remain alert and prepared.

The agency advises the public to familiarize themselves with evacuation routes, identify safe areas in their communities, and coordinate with their respective Local Disaster Risk Reduction and Management Offices for earthquake preparedness measures.

While the movement of these fault lines cannot be predicted, understanding their presence and potential impact can help communities reduce risks and respond more effectively when strong earthquakes occur.