An earthquake measuring 5.3 on the Richter scale rocked Burgos town in the northern Philippine province of Ilocos Norte at 1:56 p.m. local time Monday, the Philippine Institute of Volcanology and Seismology said. The Philippine government is still determining whether there were casualties or losses in Ilocos Norte towns affected by the earthquake. The epicenter of the earthquake was determined to be 87 km west of the coastal town of Burgos, with a depth of 25 km. The Philippines sits in the so called "Pacific Ring of Fire," an area where continental plates collide, producing frequent earthquakes and volcanic activities.