DUMAGUETE CITY, Philippines – Authorities of the Philippine Institute of Volcanology and Seismology (Phivolcs) are now doing a trace on a possible fault line near this capital of Negros Oriental that could have triggered the seismic activity early this week.
Joe Molas, science research analyst of the Phivolcs seismic station in Brgy. San Antonio of Sibulan town in Negros Oriental, confirmed that initial assessment of the tremor that rocked Dumaguete and nearby areas Monday evening was locally generated.
A magnitude-3.0 earthquake jolted Dumaguete and the nearby Sibulan and Valencia towns, at around 9:26 p.m. Monday. No damage was reported however in those areas.
The brief tremor was felt at Intensity III in Valencia, Intensity II in Dumaguete and Intensity I in Sibulan, said Molas. An aftershock was reported after the first quake but it was too weak to be even plotted on the seismic equipment, said Molas.
An official report from the Phivolcs said the earthquake was tectonic in origin and its epicenter close to Valencia, where Mount Talinis is situated.
Phivolcs said the tremor was measured at a depth of 03 kilometers, 09.30N, 123.15E or 14 kilometers N 83° W of Valencia.
The Phivolcs stations in Tagbilaran, Bohol, Lapu-Lapu City in Cebu and Roxas City are now helping out in tracking the local origin of the earthquake, said Molas.
Former Environment Sec. Dr. Angel Alcala had previously warned of at least four intersecting geologic faults that put Dumaguete, Valencia, Sibulan, San Jose and Amlan at risk.
Majority of the earthquakes felt in Dumaguete and other parts of Negros Oriental in previous years were generated not by a local fault but by an oceanic trench, ( a linear depression of the sea floor caused by the subduction of one plate under another), such as that of the Negros Trench. (FREEMAN)