Four moderate earthquake struck off the provinces of Cagayan, Batangas, Occidental Mindoro and Pangasinan on Thursday morning, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.
In its bulletin, the agency said the first earthquake with magnitude 3.7 occurred at 2:34 a.m. with its epicenter traced at 13 kilometers southwest of Santa Ana in Cagayan.
The quake which was tectonic in origin, had a depth of 12 kilometers.
The second quake with a magnitude 4.2 occurred at 3:03 a.m. with epicenter traced 18 km southwest of Nasugbu, Batangas.
The quake was also tectonic in origin and had a depth of 106 kilometers.
The third quake with a magnitude 3.0 quake occurred at 4:39 a.m. with its epicenter traced 30 km southwest of Lubang in Occidental Mindoro and had depth of 32 kilometers.
The fourth quake happened around 5:46 a.m. — magnitude 3.6 — and the epicenter traced at five kilometers southeast of Bolinao in Pangasinan and had a depth of 25 kilometers.
Phivolcs said no damage was reported from the earthquake since it happened offshore.
Phivolcs said an average of 20 earthquakes hit the country daily as the Philippines lies on the Pacific Ring of Fire, where earthquakes and volcanic eruptions are frequent due to friction between shifting tectonic plates.