Quakes rock Bicol, E. Visayas, Ilocos

MANILA, Philippines - The “earthquake swarm” that has hit Batangas and other parts of Luzon could last for days or weeks, state seismologists warned yesterday.

Earthquakes also jolted Eastern Visayas, the Bicol region, Ilocos Sur and Davao yesterday, just two days after powerful quakes rocked Batangas.

Renato Solidum, director of the Philippine Institute of Volcanology and Seismology (Phivolcs), explained that the series of earthquakes in Batangas were related as one fault “was moving incrementally and generates succeeding or successive small earthquake events.”

But he said the unnamed fault along the Mabini peninsula that has been causing the earthquake swarm in Batangas is unlikely to produce stronger earthquakes.

“This is not a major fault that’s why we don’t expect it to cause stronger earthquakes,” he said in an interview.

“An earthquake swarm can last for days or even weeks so there can still be earthquakes in the next few days,” he added.

More than 1,000 aftershocks have been recorded as of yesterday from the magnitude 5.5 main shock, but most of these were unfelt.

Four strong earthquakes struck Batangas one after another on Saturday afternoon. Shockwaves reached nearby areas, including Metro Manila.

The first quake measuring magnitude 5.6 hit at 3:07 p.m. Its epicenter was two kilometers northwest of Mabini, Batangas.

Two minutes later, a magnitude 6 quake struck at 12 km northwest of Mabini.

The third earthquake measuring magnitude 4.1 was felt at 3:29 p.m., while a magnitude 4.7 tremor was felt at 4:36 p.m.

 Quakes hit Visayas, Bicol, Ilocos, Davao

Two days later, two earthquakes jolted Eastern Visayas, the Bicol region, Ilocos Sur, and Davao City.

A magnitude 5.4 earthquake hit parts of Eastern Visayas and the Bicol region yesterday but there were no reports of damage or injuries, Phivolcs said.

The quake occurred at 8:43 a.m. yesterday with its epicenter traced to 74 kilometers northeast of Palapag, Northern Samar. 

It was felt at Intensity 3 in Palapag, Northern Samar; Intensity 2 in Catarman, Northern Samar; Cabid-an and Juban, Sorsogon; and Panganiban, Catanduanes; and Intensity 1 in Tacloban City, Leyte.

Phivolcs warned of possible aftershocks from the tremor. 

Another earthquake with a magnitude of 3.7 rattled parts of Ilocos Sur at 8:18 a.m. yesterday. It was centered 13 km northwest of Sinait, Ilocos Sur. It was felt at Intensity 3 in Vigan, Sinait and Bantay, Ilocos Sur. 

Solidum said the tremors in Samar and Ilocos Sur were not related to the quake that hit Batangas on Saturday afternoon.

Solidum said the Samar quake was caused by a movement of the Philippine Trench, while the Batangas earthquakes were due to a local fault.