Published: Saturday 12 August, 2017

Magnitude 6.3 Earthquake in Lian, Batangas NOT Related to the ‘Big One’ Quake

The strong earthquake in Luzon Friday, August 11, was not related to the BIG ONE. This according to the Philippine Institute of Volcanology and Seismology (Phivolcs) amid fears that the magnitude 6.3 earthquake traced to Lian, Batangas was a precursor to the Big One earthquake to be generated by the West Valley Fault.

Lian Batangas earthquake August 11

The Lian, Batangas earthquake of August 11, 2017. (Phivolcs)

The 6.3-magnitude earthquake occurred at 1:28 PM on August 11. It caused mild panic all over Luzon. Students and office workers ran out of buildings in Metro Manila, Batangas and other Calabarzon areas as the quake rumbled.

According to Phivolcs, the earthquake had a depth of 177 kilometers. This was the reason why the area affected is so wide. People as afar as Pangasinan felt the earthquake.

As per Phivolcs’ bulletin, the intensity of the tremor is as follows:

Intensity IV – Nasugbu, Calatagan & Balayan, Batangas; Calapan, Sablayan & Mamburao, Occidental Mindoro; Manila; Paranaque City; Pasig City;Taguig City; Pasay City; Rosario, Maragondon, Noveleta & Dasmarinas, Cavite; Floridablanca, Pampanga; Olongapo City; Subic & Iba, Zambales

Intensity III – Puerto Galera, Oriental Mindoro; San Jose, Occidental Mindoro; Tagaytay City; Canlubang & Calamba, Laguna; Indang & Alfonso Cavite; Bocaue, Malolos, Obando & Balagtas, Bulacan; Dagupan City; Dau, Pampanga; Lingayen, Pangasinan; Bagac, Bataan; Baguio City; Pateros; Quezon City; Makati City; San Juan City; Marikina City; Cainta & San Mateo, Rizal;

Intensity II – Sta Rosa, Laguna; Gasan, Marinduque; Magalang & Sto. Tomas, Pampanga; Tanauan City Batangas

Intensity I – Talisay, Batangas; Pantabangan, Nueva Ecija; Meycauayan, Bulacan; Atok, Benguet.

Many residents, especially those in Metro Manila, feared that Friday’s quake was a presurcor to The BIG ONE, the projected 7.2-magnitude earthquake to be generated by the West Valley Fault. But Philvocs said it was not.

The Lian, Batangas earthquake was caused by movement in the Manila Trench, an oceanic trench in the West Philippine Sea. This is not connected to the West Valley Fault that runs from Aurora province to Laguna, and passes through very populated areas in Metro Manila including Quezon City, Pasig and Marikina.