By the Bohol Chronicle
Three active fault lines could trigger a destructive earthquake in Bohol that would cause deaths and wreak damage to properties, an official of the Philippine Institute of Volcanology and Seismology (Phivolcs) bared yesterday.
Phivolcs-Bohol chief Engr. Eusil Talisic has advised Boholanos to be ready for a big quake that could reach a maximum magnitude of 7 or even higher on the Richter scale, although no one could exactly say when it can happen.
Talisic said that an earthquake with a high magnitude could occur anytime because of three fault zones - the East Bohol Fault, North Offshore Fault and the South Offshore Fault.
The death toll may not be as high as the world's most devastating quakes, such as the recent one in Haiti , since two of the fault lines are offshore.
The East Bohol Fault traverses through the eastern municipalities of Loay, Lila, Dimiao and Valencia , going to the interior towns of Carmen, Sierra Bullones and Pilar.
Based on scientific data, the South Offshore Fault, lying between Bohol and Camiguin Island , has recorded a maximum intensity of 7.5 in the Richter scale on February 1990. The tremor was felt inland that brought destruction on the St. Michael the Archangel Church and several bridges in Jagna.
A strong tremor may cause tidal disturbances which could flush out coastal communities within proximity of the quake's epicenter.
Situated in between Cebu and Bohol, the North Offshore Fault line recorded a maximum intensity of 6.2 in the Richter scale during a quake in 1922.
A magnitude 6 earthquake is already destructive according to Talisic especially when its epicenter would hit a densely populated area.
According to Talisic, the East Bohol Fault traverses through mostly mountainous areas.
After the dreadful earthquake in Haiti, seismic activities have been observed to be more frequent in the Visayas and Mindanao areas.
But Talisic said the tremor in the Caribbean nation was not a triggering factor, the fault lines in Bohol being thrust faults in nature.
The Phivolcs registers an average of 20 seismic activities daily throughout the country, but most are low intensity disturbances and only a few of them are actually felt.
Recent quakes that jolted the Visayas and Mindanao occurred last January 21 in Northern Samar with a magnitude of 4.8; January 21 in Surigao del Sur which registered a magnitude of 3.2; January 17 in Canlaon City, Negros Oriental with a magnitude of 2.2; a 5.3 magnitude quake which jolted Davao last January 15; and a 5.1 magnitude tremor in Sultan Kudarat province last January 13.
The Philippines sits on the Pacific Ring of Fire, where frequent seismic and volcanic activities are caused when continental plates collide.