Quake epicenter (Image grabbed from Phivolcs' website)

MANILA – A magnitude 5.6 earthquake jolted Cagayan province on Thursday, the Philippine Institute of Volcanology and Seismology (Phivolcs) reported.

The tectonic quake struck 17 kilometers northwest of Dalupiri Island in Calayan at 7:31 a.m. It was 15 km deep.

Intensity V was felt in Calayan, Cagayan, and intensity II in Flora and Santa Marcela, Apayao.

Phivolcs also logged the following instrumental Intensities:

Intensity III - Pasuquin, Ilocos Norte
Intensity II - Laoag, Ilocos Norte; Narvacan, Ilocos Sur
Intensity I - Peñablanca and Gonzaga, Cagayan; Batac, Ilocos Norte; Sinait, Ilocos Sur

Reported intensity is the traditional way of knowing the intensity based on reports of people who felt the earthquake. Instrumental intensity, on the other hand, is measured using an intensity meter that measures ground acceleration.

Phivolcs said aftershocks are likely, but damage is not expected from the magnitude 5.6 quake. (PNA)