Manila: Philippine Institute of Volcanology and Seismology (Phivolcs) Director Teresito Bacolcol on Wednesday said a strong earthquake is not expected despite the earthquake swarm recorded near the boundary of Isabela, Ifugao, and Mountain Province since June 1. The swarm or series of numerous weak quakes in a local area started at 10:08 p.m. on June 1.

According to Philippines News Agency, as of 8 a.m. on June 4, Phivolcs recorded 416 earthquakes, including 135 plotted or located earthquakes, ranging from magnitudes 1.2 to 3.6, and were 2 to 39 kilometers deep. None of these were reportedly felt. "Unlike aftershocks that consist of at least one strong earthquake or main shock followed by small earthquakes, swarms don't have a single main shock," Bacolcol told the Philippine News Agency in an interview.

Swarm is usually triggered by active faults. Bacolcol said there are active faults in the area where Phivolcs observed the swarm since June 1. The nearest is the East Cordillera Fault. This implies that there is an ongoing fault activity in the area, but this does not necessarily mean a strong earthquake would follow, he emphasized.

"Even if the earthquakes are weak and not felt, people should always be prepared," he pointed out. He said Phivolcs has posted about the seismic activity on its social media page not to scare the public, but to inform them of the activities that need to be monitored. Further, the post is part of Phivolcs' commitment to providing the right information to the public, he said.