Phivolcs: West Valley Fault May Cause 7.2-Magnitude Earthquake in Metro Manila

Marikina West Valley Fault map

The Philippine Institute of Volcanology and Seismology (Phivolcs) issued a warning on Friday, May 15, 2015 that the West Valley Fault System (formerly called Marikina Fault) is now ripe and may move. Once this happens, the Phivolcs said that there is a huge possibility of a 7.2-magnitude earthquake in Metro Manila and nearby areas.

In an interview on dzMM, Phivolcs director Renato Solidum said people should always be prepared in case their prediction happens. Phivolcs has been warning the public about the possible movement of West Valley Fault since 2013, and estimated to cause around 33,500 casualties and around 113,600 injuries.

“Dito sa West Valley Fault, ang kada galaw niya ay 400 to 600 years at ang last niyang gumalaw ay 1658, 357 years ago. So 357 and 400, magkalapit ‘yan kasi either gumalaw ‘yung fault nang mas maaga or mas later,” Solidum told the radio station, reminding everyone to prepare for the worst.

(The movement of West Valley Fault is every 400 to 600 years, and the last time it moved was in 1658, or 357 years ago. And because 357 and 400 are near, it can move sooner than predicted, or probably later.)

The Marikina Valley Fault contains two major segments – 10-kilometer East Marikina Valley Fault (EMVF) in Rizal, and the 100-kilometer West Marikina Valley Fault (WMVF), which runs through Bulacan, Cavite, Laguna, Makati, Marikina, Muntinlupa Pasig, Quezon City, Rizal, and Taguig.

According to Phivolcs, the movement of West Valley Fault can generate a 7.2-magnitude earthquake which is enough to destroy buildings, infrastructures, and livelihood, and is also very much likely to cause thousands of casualties and injuries. No estimated figures were released, but are expected to be higher than in 2013.

This latest warning from Phivolcs comes after a 7.8-magnitude earthquake hit Nepal on April 25, where more than 8,000 people died and more than 19,000 people were injured. After some strong aftershocks, a 7.3-magnitude earthquake hit the country again on May 12, or three weeks later.

After the Nepal earthquake this April, the country’s geoscientists discovered that the fault segment moves every 750 years, plus or minus hundred plus years. And because its last movement was in 1344, the earthquake is somehow bound to happen.” Solidum said.

In line with this, the Phivolcs issued a press release on Friday, May 15, announcing the launch of the Valley Fault System (VFS) Atlas, a map handbook showing the details of the areas traversed by the Valley Fault System. They will be distributed to local government officials on Monday, May 18, 2015, 9 am at the 2/F Auditorium, PHIVOLCS Building, C.P. Garcia Avenue, UP Campus, Diliman, Quezon City.

“The Valley Fault System Atlas was conceptualized as a handy reference for everyone to serve as a guide in making sure that areas traversed by active faults are avoided as sites of houses and structures and considered in various mitigation and response actions to enhance the safety and resilience of communities to strong earthquake events.” Solidum was quoted in the press release.

“Through the publication of this Atlas, which specify the position and location of the Valley Fault System in GMMA, we have taken a leap forward to reducing risk from earthquake.” National Disaster Risk Reduction and Management Council (NDRRMC) Executive Director Undersecretary Alexander P. Pama said.

Due to this threat, all construction projects and business establishments should comply with the National Building Code, wherein all buildings should be designed to withstand earthquakes between Intensity 8 to Intensity 10. The public is also being advised not to panic and instead prepare on what to do in case an earthquake occurs.