Two moderate earthquakes hit off Basco, Batanes on Friday, the US Geological Survey said.

There were no immediate reports of damage or injuries from the undersea tremors that struck about an hour apart.

At 9:43 a.m., a 4.9 magnitude quake occurred about 15 kilometers southeast of Basco town at a shallow depth of 34.9 kilometers.

At 8:44 a.m., a 4.8 magnitude earthquake hit off the coasts of Batan Islands with an epicenter traced at 25 kilometers south-southeast of Basco. It was located at a depth of 32.1 kilometers.

On Thursday, a moderate 4.7 magnitude earthquake jolted Batanes and was centered near where Friday’s tremors occurred.

A strong quake measuring 6.1 magnitude on the Richter Scale rocked Cagayan province on Tuesday. Its epicenter was traced 130 kilometers north-northeast of Tuguegarao City at a shallow depth of 29.6 kilometers.

On Monday, a 4.9 quake struck off Babuyan Islands.

The Philippines sits on the Pacific Ring of Fire, where continental plates collide causing frequent seismic and volcanic activity.