The Philippine Institute of Volcanology and Seismology (Phivolcs) added five more digital seismograph stations in Negros Oriental after the magnitude 6.9 earthquake devastated the northern part of the province.
Philvocs Chief geologist and geophysicist Dr. Arturo Daag in a media briefing said that the seismographs installed determine the correct sites of potential earthquakes and to monitor tectonic quakes.
The new seismograph stations are located in the Tayasan, Vallehermoso, Mabinay towns in Negros Oriental, and neighboring areas of Kabankalan and Badian, Cebu other than that in Sibulan.
Dr. Daag said that since nobody can predict the occurrence of earthquakes but with some equipment that can measure its effects. The unidentified fault line triggered the intensity 7 earthquake that rocked Negros Oriental and nearby provinces, said geologist Daag.
The magnitude of an earthquake depends on the amount of energy released during the earthquake; the intensity is based on the damaged felt in an area, Daag explained.
He added Phivolcs’ earthquake intensity scale uses roman numerals from 1 to 10, where 10 is completely devastating and 1 scarcely perceptible; 7 is destructive or damaging.
Since the country is located in the Pacific Ring of Fire, it experiences more than three earthquakes daily of varying intensities, thus many fault lines are yet to be mapped out, Phivolcs official said.
The significant destructive earthquake in Negros Oriental had caused major damages with about 15,000 houses shattered and 53 deaths with 60 persons still missing as reported by the Provincial Disaster Risk Reduction and Management Council (PDRRMC) as of February 21, 2012.
Some 62,700 families or more than 300,000 persons were affected in 166 barangays from the nine local government units. Relief operation centers recorded P38.8 million cost of assistance needed, said PDRRMC Executive Officer Adrian Sedillo. (mbcn/JCT/PIA-NegOr)