2 major quakes in Surigao del Sur due to PH Trench movement – Phivolcs

Metro Manila (CNN Philippines, December 5) — The two recent earthquakes that jolted Surigao del Sur were due to the movement of the Philippine Trench, the Philippine Institute of Volcanology and Seismology (Phivolcs) explained.

A magnitude 7.4 tremor struck the town of Hinatuan on Saturday, while a magnitude 6.8 quake hit the town of Cagwait on Monday.

«Related yung dalawa in a sense na both were generated by the Philippine Trench,» said Phivolcs director Teresito Bacolcol in an interview with CNN Philippines' Balitaan on Tuesday.

[Translation: The two were related in a sense that they were both generated by the Philippine Trench.]

The Phivolcs chief, however, reiterated that the incidents were isolated from each other.

«But yung (the) 6.8 in Cagwait is not an aftershock of the Dec. 2 event, it's a different earthquake,» he explained. «For one, yung magnitude 6.8 is too large to be considered as an aftershock of the 7.4.»

He added that such a scenario along the Philippine Trench already happened back in 1992 also in Mindanao.

«Nangyari na po ito nung 1992, mayroon po tayong magkasunod na earthquakes, 26 minutes apart lang,» Bacolcol pointed out. "'Yung isa 7.1, yung isa 7.5. So hindi na po ito bago sa Philippine Trench."

[Translation: This already happened in 1992, where we had two consecutive earthquakes that were just 26 minutes apart. One was a magnitude 7.1, while the other was a magnitude 7.5. So this is not something new with the Philippine Trench.]

According to the latest data by the National Disaster Risk Reduction and Management Council, the magnitude 7.4 quake in Hinatuan left one dead and 12 injured.

In separate advisories on Tuesday morning and afternoon, Phivolcs recorded two magnitude 5.7 quake aftershocks hitting Cagwait in Surigao Del Sur at 08:34 a.m and 5:42 p.m.

The agency said that these were aftershocks of the 6.8 quake on Dec. 4, Monday in Cagwait.

While aftershocks are expected, Phivolcs said their intensity will go down after several days.

«Yung mga aftershock, for example yung sa magnitude 7.4 (For the aftershocks, just like with the magnitude 7.4), we would expect moderate to strong aftershocks for several days up to several