Phivolcs: Manila Trench movement could generate 5.5-meter tsunami

MANILA, Philippines — The Philippine Institute of Volcanology and Seismology (Phivolcs) has urged Filipinos to take precautions, warning that strong movement along the Manila Trench could generate a tsunami reaching 5.5 meters.

On Tuesday, Phivolcs outlined its tsunami risk reduction initiatives ahead of World Tsunami Awareness Day on November 5. During a press conference, Director Mylene Villegas was asked whether the Manila Trench or the West Valley Fault could trigger a strong tsunami.

Villegas explained that movement along the Manila Trench could generate a tsunami, while movement along the West Valley Fault could cause earthquakes on land, particularly the “Big One.”

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“A magnitude 8.3 earthquake from the Manila Trench could generate a tsunami reaching 5.5 meters, while a maximum magnitude 7.2 earthquake from the Valley Fault, based on their modeling, could cause major damage to the affected areas and nearby places,” she added.

Villegas also noted that the Philippines is prone to tsunamis because of earthquake generators, active faults and trenches in the eastern and western parts of the country.

She said 66 of the country’s 82 provinces are at risk from the devastating impacts of tsunamis.

“There are two types: local tsunamis generated by local earthquake sources, such as the Philippine Trench, Manila Trench and Cotabato Trench, and tsunamis that could affect our provinces on the Pacific side, caused by earthquakes originating in the Pacific Ocean,” she added.

READ: Phivolcs to public: No to complacency, be prepared for strong quakes

She also said eight Metro Manila cities are prone to tsunamis. Phivolcs identified these as Valenzuela, Navotas, Malabon, Pasay, Las Piñas, Parañaque, and Manila.

Office of Civil Defense National Capital Region Director George Keyser noted that Makati may also be affected because of the Pasig River corridor.

Villegas underscored the importance of watching for natural signs of a tsunami, such as an earthquake, the sudden receding of the ocean, and a loud roaring sound. She added that tsunamis can occur five to 20 minutes after an earthquake.

She also noted that tsunamis generated by local earthquakes may arrive faster than those caused by earthquakes in the Pacific or other countries.

Keyser said proper information dissemination, including clear and consistent messaging about tsunami impacts, locally appropriate evacuation planning, and coordination among local government units and concerned agencies, are essential for a quick response when a tsunami strikes the country. /mcm