Twin strong aftershocks strike waters off Cagwait, Surigao del Sur
MANILA, Philippines — Two successive strong tremors with magnitudes 5.7 and 5.5 rocked the waters off Cagwait town in Surigao del Sur on Tuesday afternoon, which were the aftershocks of the magnitude 6.8 earthquake in the area the day before, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).
The latest magnitude 5.7 tectonic earthquake occurred 56 kilometers northeast of the said town at around 5:42 p.m., with a shallow depth of one kilometer (km).
Felt intensity (intensity IV moderately strong) was reported at Tandag City, Surigao del Sur, while Phivolcs logged an instrumental intensity II (weak) in the same city.
This tremor succeeded the magnitude 5.5 earthquake which occurred 69 km northeast of the said municipality at 5:10 p.m. The tectonic temblor also has a shallow depth of 10 km.
As of Tuesday, over 500 aftershocks were recorded following the 6.8-magnitude tremor which struck 63 kilometers east-southeast of Cagwait at 3:49 a.m. on Monday with a shallow depth of focus of one km.
It was triggered by the Philippine trench, just like the powerful 7.4 earthquake off Hinatuan town in the same province over the weekend.
The Philippines sits on the Pacific Ring of Fire where tectonic plates collide, causing frequent earthquakes and volcanic activity.