Magnitude 6.6 quake in Masbate caused by movement of PH fault zone – Phivolcs

MANILA, Philippines — The magnitude 6.6 earthquake (earlier reported as magnitude 6.5)  that struck Masbate province Tuesday morning was caused by the movement of the Philippine fault zone, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

“It’s because of the movement of the Philippine fault zone. This is the Masbate segment,” Phivolcs chief Renato Solidum said in Filipino over ABS-CBN’s “Teleradyo” when asked for the origin of the strong quake.

Information from Phivolcs showed that the earthquake struck five kilometers southwest of Cataingan town at 8:03 a.m. Intensity IV was recorded in Mapanas, Northern Samar; Legazpi City, Albay; and Lezo, Aklan, while intensities were also reported in other nearby areas.

“The epicenter of the quake is in Cataingan. The fault in the area has been moving in the past few days,” Solidum said.

“If you can remember, in the early 2000s, there was also a magnitude six-plus earthquake in the northern segment of the fault in Masbate. Cataingan is part of the epicenter of smaller earthquakes in the past days,” he added.

According to the Phivolcs website, the 1,200-kilometers-long Philippine fault zone is a major tectonic feature that transects the whole Philippine archipelago from northwestern Luzon to southeastern Mindanao.

This arc-parallel, left-lateral strike slip fault is divided into several segments and has been the source of strong earthquakes in the recent years, such as the 1973 Ragay Gulf earthquake (M 7.0), 1990 Luzon earthquake (Mw 7.7), and 2003 Masbate earthquake (Ms 6.2), according to the agency.

Solidum said Phivolcs is not discounting the possibility that there could be a stronger earthquake in Masbate but added that the succeeding earthquakes or aftershocks will most likely be weaker.

JE