A predawn magnitude 5.7 quake jolted parts of Northern Luzon, some 400 km north of Manila on Tuesday.
Philippine Institute of Volcanology and Seismology head Renato Solidum Jr. said the quake was recorded at 3:58 a.m., with the epicenter traced at 27 km northeast of Laoag City, the capital of Ilocos Norte.
Citing initial reports, Solidum said the quake was felt at Intensity V in Laoag City, Burgos, Pasuquin, Sarrat, and Batac towns in Ilocos Norte; Intensity IV in Sinait, Ilocos Sur; Intensity III in Tuguegarao and Peñablanca in Cagayan, and Intensity II in Santa and Vigan City in Ilocos Sur, and Baguio City.
Meanwhile, the United States Geological Survey (USGS) recorded the quake at magnitude-5.9, tracing the epicenter at 184 km northwest of Ilagan, Isabela; 228 km north of Baguio City; or 427 km north of Manila.
The National Disaster Coordinating Center said there were no immediate reports of damage.
The Philippines sits on the Pacific Ring of Fire, where continental plates meet, causing frequent seismic and volcanic activity. (PIA-Bohol)