MANILA, Philippines --- A 6.1-magnitude earthquake jolted the sea off Luzon at 6:19 a.m. on Sunday, with the United States Geological Survey placing the epicenter 143 kilometers (km) southwest of Baguio and 181 km northwest of Manila at a depth of 35 km.
The quake was actually one of six earthquakes that hit the country on Sunday, with the earliest coming at 1:18 a.m. just 5 km northwest of La Trinidad, Benguet, with the epicenter 79 km beneath the surface.
It was followed by a magnitude 6 at 6:18 a.m. located 80 km southwest of Candelaria, Zambales, with the epicenter placed just 4 km below the surface.
Three succeeding quakes occurred after this big tremor, with epicenters ranging from 24 km to 53 km southwest of the same Zambales town.
Data from the Philippine Institute of Volcanology and Seismology (Phivolcs) showed that a magnitude 3 quake happened at 6:37 a.m., with the epicenter 22 km below the surface in an area 52 km southwest of Candelaria.
This was followed by a magnitude 3.3 quake that rattled the earth 19 km below the surface of the sea 53 km from the same town at 6:49 a.m.
Phivolcs said the latest Candelaria quake happened at 7:05 a.m. just 3 km below the surface 24 km northwest of Candelaria.
While the Philippines sits within the Pacific Ring of Fire, owing to huge plate movements and the string of volcanoes, both above ground and underwater, it has not had a major earthquake since February, when landslides triggered by a 6.7 temblor killed hundreds in Negros Island and neighboring areas.
Manila is straddled by a number of faults, some small and some big, and geologists and seismologists have asked government to prevent earthquakes and tsunamis that could potentially kill 35,000 people and destroy hundreds of thousands of homes and buildings.
Aside from towns in Zambales, Dagupan City, Bugallon, Villasis, and Bolinao towns in Pangasinan, and Makati City also felt the earthquake at Intensity 4.
Intensity 3 was felt in San Fernando City, La Union and Quezon City, while Intensity 2 was felt in Bacoor, Cavite and in Plaridel, Bulacan. Intensity 1 was felt in Tagaytay City.
Three aftershocks were felt after the earthquake, with the strongest having a 3.3-magnitude.
Zambales is assessing the damage brought about by the earthquake, although officials said they expect the damage to be minimal.
As this developed, residents of Dagupan City in Pangasinan were shocked, fearing another strong quake of the same intensity with the July 16, 1990 quake which damaged the city.
The Sunday earthquake lasted a few seconds, rocking Dagupan City at 6:18 a.m., and its epicenter established at 52 kilometers southwest of Candelaria, Zambales, near the Manila Trench.
Based on Phivolcs report, the earthquake, felt in Pangasinan, was recorded at 6 magnitude and tectonic in origin.
Police said no one was reported hurt in the earthquake, but the incident created panic among the residents of Dagupan City.
The city government of Dagupan recently installed an earthquake evacuation maps in different public schools as a precaution against calamity or disaster. (With reports from Jonas Reyes and Liezle Basa Inigo)