Magnitude 5.1 earthquake rocks Ilocos Sur

The Philippine Institute of Volcanology and Seismology (Phivolcs) shows the epicenter of a magnitude 5.1 earthquake that shook the waters off of Ilocos Sur on Wednesday. (Image from DOST/Phivolcs)

MANILA, Philippines — An earthquake with a magnitude of 5.1 hit the waters of Ilocos Sur at 3:59 a.m. on Wednesday, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

The quake’s epicenter was located 57 kilometers (km) west of San Esteban in Ilocos Sur. The tremor had a depth of focus of 10 km and was tectonic in origin.

While state seismologists said that they are not expecting damage from the temblor, they are expecting aftershocks to occur.

In response, the National Disaster Risk Reduction and Management Council advised residents in Ilocos Sur to take caution in case of possible aftershocks.

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According to Phivolcs, instrumental intensity 2 (slightly felt) was recorded in the City of Vigan in Ilocos Sur due to the earthquake.

Instrumental intensity is determined by Phivolcs’ intensity meters in and around the epicentral area.

The Philippines sits on the Pacific “Ring of Fire,” where tectonic plates collide, causing frequent earthquakes and volcanic activity.