A magnitude 5.3 earthquake struck the waters northwest of Dalupiri Island in Calayan municipality, Cagayan, in the early hours of Thursday, the Philippine Institute of Volcanology and Seismology said. The quake was tectonic in origin, occurred at a depth of about 10 km, and was not expected to produce significant damage. Aftershocks remain possible through the weekend.
No injuries were reported in Calayan or the adjacent Babuyan group of islands. Local officials in Aparri said the tremor was felt as a brief, sharp shake without sustained motion. Power and telecommunications across northern Cagayan held up.
The seismic event lands during an active month for Philippine geophysics. Mayon volcano in Albay province, southeast of Manila, has remained at alert level 3 on a 0-5 scale, with continuous low-level eruption and lava effusion now in its sixth week. Tens of thousands of residents in the 6-km permanent danger zone and the 7-km extended danger zone remain in evacuation centres.
The Philippine Atmospheric, Geophysical and Astronomical Services Administration has separately flagged the early formation of a tropical depression east of Mindanao, with a potential to develop into the season's first named storm by next week. Provincial disaster offices in Eastern Visayas have been told to pre-position resources.
Phivolcs reiterated its standing guidance that residents in earthquake-prone northern Luzon should secure heavy furniture and keep emergency kits ready, and that those near Mayon should avoid the danger zones regardless of the volcano's relatively quiet recent days.