MANILA, July 15 (Xinhua) -- An offshore earthquake with a preliminary magnitude of 5.8 struck the northern Philippine province of Ilocos Norte on Tuesday morning, the Philippine Institute of Volcanology and Seismology reported.

The institute said that the quake, which occurred at 10:38 a.m. local time, struck at a depth of 27 km, approximately 29 km northwest of Pasuquin town.

The institute said the tectonic quake will trigger aftershocks but is unlikely to cause significant damage.

The tremor also shook the neighboring provinces of Cagayan, Ilocos Sur, Isabela, and Abra.

The Philippines has frequent seismic activities due to its location along the Pacific Ring of Fire. ■