Volcanologists uncover 3 Cebu fault lines

Cebu City – The Philippine Institute of Volcanology and Seismology (Phivolcs) yesterday said Cebu has three probable fault lines that could cause a series of earthquakes in the province.

In his presentation before the Provincial Board (PB) of Cebu, Phivolcs supervising science research specialist Jeffrey Perez identified the possible local locations of the three fault lines in its hazard map, which was taken using overhead satellite imagery, in the interior parts of the south and Central Cebu.

Perez said there are two traces of the fault lines in the interior parts of the south, situated opposite each other, while the another fault line is located somewhere in Central Cebu.

Although Perez did not give the exact locations of the possible faults, based on the Cebu provincial map, Central Cebu covers the Cebu Metropolitan Area and the neighboring cities of Danao, Lapu-Lapu, Mandaue, and Talisay. It also spans the mountain areas near the boundary of Cebu City and Balamban town and Toledo City.

The interior parts of southern Cebu, meanwhile, comprise the towns of Oslob, Ginatilan, Boljoon, Alegria, and Alcoy. The towns of Boljoon, Oslob, and Alcoy are situated opposite of Ginatilan, Malabuyoc, and Alegria.

Phivolcs said there are no traces of fault lines in the north but it does not mean the area is safe, he said, adding that the locality could still be hit by the impact of a quake caused by other fault lines.

He urged leaders of the province to prepare for the eventual rupture of the fault lines.

Asked by PB Member Jose Ribomapil Holganza Jr. if there is a device that can be placed in the ground to pinpoint the exact location of the fault, Perez said there are geophysical instruments that can be used to spot the location of the fault but the equipment is expensive.

He said they would look for and use aerial photographs to clearly identify the exact locations of the fault lines.

Aside from ascertaining the exact location of the faults, Phivolcs is also studying the strength of ground-shaking these faults can cause.

As this developed, Cebu Governor Hilario Davide III was set to meet officers of the Provincial Heritage Commission to discuss immediate ways to repair and restore churches in southern Cebu that were partly damaged by the 7.2-magnitude earthquake that hit Cebu and Bohol last week.

Davide said he wants to know how the province can help in restoring the affected churches, which include the Boljoon church, a national heritage site. Also damaged during the earthquake were the centuries-old churches in Dalaguete and Oslob towns.