Minor earthquakes rock Zamboanga and Masbate

A magnitude 4.1 earthquake occurred in the province of Zamboanga del Norte on October 24, 2023. (Photo from Phivolcs)

MANILA, Philippines — Separate earthquakes rocked the provinces of Zamboanga del Norte and Masbate on Tuesday, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

According to Phivolcs, a magnitude 4.1 temblor hit the waters of Siocon, Zamboanga del Norte at 7:53 p.m.

Based on the agency’s earthquake information, the shaking was tectonic in origin and had a six-kilometer depth of focus.

Phivolcs indicated that an Intensity IV and Instrumental Intensity IV was reported in Siocon, Zamboanga del Norte, while Instrumental Intensity I was detected in the City of Zamboanga.

In a previous interview with INQUIRER.net, Phivolcs Science Research Analyst Lara Guianan explained that intensity is based on the ground motion actually felt by people in the affected area, while instrumental intensity is the quake’s strength as measured by an intensity meter or scale.

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Earlier on Tuesday, at 8:26 a.m., an earthquake also occurred in Uson, Masbate.

Phivolcs said the magnitude 3.7 temblor was likewise tectonic in origin and had a six-kilometer depth of focus.

The agency reported that Intensity III and Instrumental Intensity III were recorded in Uson, Masbate, while Instrumental Intensity II was detected in the City of Masbate.

Phivolcs noted that no damage nor aftershock is expected from the two earthquakes.

JMS