MANILA (UPDATED) - Homes and buildings in Metro Manila are found on top of a major fault system that can cause a magnitude 7.2 earthquake anytime, according to latest data from the Philippine Institute of Volcanology and Seismology (Phivolcs).
Phivolcs on Monday released the Valley Fault System (VFS) Atlas, a handbook of large-scale maps showing in detail areas traversed by the Valley Fault System.
Copies of the atlas, which can be downloaded online, was distributed to local government officials.
The VFS is an active fault system in the Greater Metro Manila Area composed of two fault segments: the 10-km-long East Valley Fault (EVF) in Rizal and the 100-km-long West Valley Fault (WVF) that runs through different cities and towns of Bulacan, Rizal, Metro Manila, Cavite and Laguna, Phivolcs said in a press statement.
The West Valley Fault can generate a large earthquake with M 7.2 which threatens to lives, buildings and infrastructures, and livelihood.
"Key to people’s awareness and preparedness for earthquakes, appropriate land use, contingency planning for disaster response, and design of houses, buildings and infrastructures, is the location of active faults," Phivolcs Director Renato Solidum, Jr. said. "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."
With the help of Australian Aid Program-funded GMMA Ready Project under the United Nations Development Programme (UNDP), Phivolcs in 2012 reassessed the VFS and found new fault lines in the system and validated previously mapped traces.
The new atlas shows the VFS in more detail, compared to previous Phivolcs maps.
"Through the publication of this atlas, we have taken a leap forward to reducing risk from earthquake. This tool will help us in our national DRRM effort to build safer, disaster-resilient and climate-change adaptive communities throughout the country," National Disaster Risk Reduction and Management Council executive director Alexander Pama said.
37,000 fatalities in M7.2 quake
Phivolcs, in partnership with Geosciences Australia, earlier undertook a Risk Analysis Project (RAP) on the West Valley Fault, is is part of the larger VFS.
The study shows that a magnitude 7.2 earthquake may kill as many as 37,000 people in Metro Manila and Rizal, which is nearly six times more than the official death toll from Supertyphoon Yolanda. [LINK: magnitude 7.2 earthquake https://www.abs-cbnnews.com/focus/07/18/14/why-ph-still-isnt-ready-big-one]
Serious injuries are expected to run up to 148,000.
The 90-kilometer West Valley Fault runs from the Angat reservoir in Bulacan through Quezon City, Marikina, Pasig, Makati, Taguig, Muntinlupa, Rodriguez Rizal, Cavite and ends in Calamba, Laguna.
In an interview on dzMM last week, Solidum said the West Valley Fault is ripe for a strong quake and people should prepare.
"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," he added.
Valley Fault System map, via nababaha.com.