The Philippine Institute of Volcanology and Seismology (Phivolcs) so far recorded 121 aftershocks following the 6.6-magnitude earthquake in Batangas early Saturday, July 24.
The 6.6-magnitude tremor was recorded at around 4:48 a.m. Saturday.
As of 10 a.m., Phivolcs reported 121 aftershocks, ranging between magnitudes 1.6 and 5.5.
Of these aftershocks, Phivolcs said 29 were plotted or located close to the epicenter of the 6.6-magnitude earthquake in the municipality of Calatagan in Batangas province.
Phivolcs said only the 5.5-magnitude tremor at 4:57 a.m. was felt.
Science and Technology Undersecretary and Phivolcs OIC Dr. Renato Solidum Jr. pointed out that the 6.6-magnitude earthquake was not connected to the Taal Volcano's activity.
He said the earthquake was caused by the movement along the Manila Trench--an earthquake generator located offshore west of Luzon Island, roughly parallel to the Philippine archipelago in the north but veers very close to land at the southern tip of Occidental Mindoro.
"Ang lindol kaninang 4:48 ng madaling araw ay sanhi ng pagkilos ng Manila Trench kung saan bloke ng bato na galing sa West Philippine Sea ay sumusuksok pailalim at umaabot sa areas ng Calatagan at Mindoro. Ito ay walang kinalaman sa volcanic activity ng Taal (The quake earlier at 4:48 a.m. was caused by the movement of the Manila Trench where blocks of rock from the West Philippine Sea penetrated underground and reached the areas of Calatagan and Mindoro. This has nothing to do with the volcanic activity of Taal)," Solidum said.
"Minsan, ang mga lindol dito sa ilalim ng Calatagan ay nararamdaman sa Metro Manila (Sometimes, earthquakes that originate underneath Calatagan are felt in Metro Manila)," he added.
Phivolcs said the earthquake was strongly felt at Intensity V in Calapan City and Puerto Galera, Oriental Mindoro; Sablayan and Magsaysay, Occidental Mindoro; and Tagaytay City, Carmona, and Dasmarinas City, Cavite.
Meanwhile, it was "moderately strong" at Intensity IV in Quezon City; Marikina City; Manila City; Makati City; Taguig City; Valenzuela City; Pasay City; Batangas City and Talisay City, Batangas; and San Mateo, Rizal.
It was "weak" at Intensity III in Pasig City and San Jose del Monte City, Bulacan.
Phivolcs' instruments also recorded the earthquake at Intensity V in Calapan City and Puerto Galera, Oriental Mindoro; Intensity IV in Batangas City, Batangas; Carmona, Cavite; and Calumpit and Plaridel, Bulacan; Intensity III in Quezon City; Marikina City; Pasig City; Las Piñas City; Muntinlupa City; Malabon City; Navotas City; and San Ildefonso, Pandi, Malolos, San Rafael, and Marilao, Bulacan; Intensity II in San Juan City; Dagupan City; and Polillo, Quezon; and Intensity I in Guinayangan, Quezon; Magalang, Pampanga; Iriga and Sipocot, Camarines Sur; Daet, Camarines Norte; Palayan City, Nueva Ecija; Iloilo City; Kalibo, Aklan; San Jose City, Antique; and Bago City, Negros Occidental.