A 4.8-magnitude earthquake jolted Ilocos Sur at 3:59 a.m. on Wednesday, Jan. 3, the Philippine Institute of Volcanology and Seismology (Phivolcs) said.

The epicenter of the tremor was located 66 kilometers (km) southwest of Caoayan, Ilocos Sur at a shallow depth of 15 km.
Phivolcs said the quake was felt at Intensity IV (moderately strong) in San Vicente, Vican City, and Candon City in Ilocos Sur; Intensity III (weak) in Salcedo, Magsingal, and Sigay in Ilocos Sur, and Bangar in La Union; and Intensity II (slightly felt) in Santa Maria, Ilocos Sur.
The earthquake was tectonic, which means that it was caused by the movement of an active fault near the area.
Phivolcs said no damage was expected but warned the public to be cautious of possible aftershocks.