December 2 Mindanao quake unrelated to November tremors: Phivolcs

BAYUGAN CITY, Agusan del Sur – The 7.4 magnitude earthquake that struck eastern Mindanao Saturday night is not connected to the slightly weaker earthquake that rocked Saranggani and nearby provinces last month, according to the Philippine Institute of Volcanology and Seismology.

In an online briefing, Phivolcs Director Dr. Teresito Bacolcol explained the two earthquakes were generated by the movement of two different trenches.

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“It was the Cotabato trench (that triggered the November 17 event), kagabi is the Philippine trench. Hindi rin stress transfer ang nangyari dito. Stress transfer happens sa faults na magkakalapit. Magkalayo ang Cotabato trench at Philippine trench,” he explained.

The earthquake has been followed by a series of aftershocks. Based on Phivolcs' monitoring, 819 aftershocks have been recorded, 171 plotted and at least 10 were felt. The magnitude of these aftershocks range between 1.4 to 6.2.

However, Bacolcol clarified that the succeeding aftershocks cannot be considered as an earthquake swarm. He explained that by definition, such events experience numerous tremors and the difference between a main shock and aftershock is difficult to determine.

Intensity VII was felt in Tandag, Surigao Del Sur while intensity VI in Bislig.

Phivolcs warns residents to to remain alert as aftershocks may continue days or up to even weeks following a main quake.

According to initial data from NDRRMC, at least 529 families or 2,647 individuals have been affected and has left at least one dead and four people injured.

• At least 1 dead, 4 injured after quake jolts eastern Mindanao