A magnitude 6.1 earthquake hit offshore Batangas south of Metro Manila on Sunday morning.
According to the Philippine Institute of Volcanology and Seismology, the tremor occurred at 5:50 a.m. with an epicenter of 18 kilometers off the coast of Calatagan, Batangas.
Of tectonic origin, which is caused by the movement of the earth’s crust, the quake, 22 minutes after sunrise, had a depth of 122 kilometers.
Intensity 4 was felt in Batangas’ Calatagan, while Metro Manila’s Quezon City and Pasay City Pasig City; Cavite’s Tagaytay City, Mendez, Amadeo and Alfonso, and Bulacan’s Obando felt intensity 3.
Intensity 2 was recorded in Bataan’s Abucay, Bataan; Nueva Ecija’s Gapan City; Zambales’ Castillejos, Zambales; Metro Manila’s Mandaluyong City, Manila City and Makati City, and Rizal’s Tanay.
“The quake was not felt that strong due to its depth,” Phivolcs director Renato Solidum said.
Damage and aftershocks are expected, he noted.
The quake was triggered by the sliding of the Eurasian Plate against the Manila Trench, Phivolcs said.
The Philippines lies along the Pacific Ring of Fire, which causes the country to have frequent seismic and volcanic activity.
Many earthquakes of smaller magnitude occur very regularly due to the meeting of major tectonic plates in the region.
Every year, the Philippines encounters about 2,000 earthquakes. Most of them are weak, but about 12 percent are felt.
Experts say earthquakes are the result of sudden movement along faults within the Earth.
The movement releases stored-up “elastic strain” energy in the form of seismic waves, which propagate through the Earth and cause the ground surface to shake.