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FHM Longform: Where Will The Next 'Big One' Strike?

The inside story of how five geologists shook the entire country awake by mapping the West Valley Fault
by Chise Alcantara | Sep 24, 2016
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Right smack in the middle of a street somewhere in Green Meadows, you'll find an awkwardly placed marker labeled "West Valley Fault" encircled and painted in bold blocky white letters. Another noticeable thing about this strangely placed marker is that it has two huge arrows protruding out of it, facing opposite directions, which just so happens to both directly point at two even bigger houses. 

The over-imaginative mind can only visualize the ground shaking uncontrollably then splitting open, swallowing the two structures into an endless, bottomless abyss.

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Could it be possible though? A disaster movie director's wet dream turned into reality featuring Dwayne Johnson as "The Rock Who Cried Earthquake." Could it be possible for the whole of Metro Manila to be swallowed by a Pasig River tsunami? (That's a whole new campaign jingle right there). These things just seem too farfetched to be true, but what do these markers mean? And more importantly, what do they mean for the people living in these houses transected by these arrows? Someone has to dig up some facts, we guess?

"Hindi naman talaga maghihiwalay yung lupa. Sa sine lang yun nangyayari," Mabel Abigania, senior science research specialist at Phivolcs and Coastal Land Formation Specialist, assures us. "At most aakyat lang siya, yung tipong hindi na magiging magka-level yung street."

She explains to us how a ground rupture works, and we collectively sigh (one of relief, and slight twisted disappointment since it looked kinda cool in San Andreas). We also collectively regret that though when we learn how devastating a 7.2-magnitude, 8-intensity earthquake (that's the predicted numbers for the earthquake the can be produced by the West Valley Fault) can do.

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According to the Earthquake Hazards Presentation, a manual Phivolcs representatives give concerned citizens who want to know more about hazard prevention, the predicted earthquake will cause structures to move and fall, as well as cause possible landslides, fire hazards, and liquefaction of water-saturated land. The intensity of the earthquake depends on the estimated effect an earthquake will have on people, structures, and the environment. To concretize this, intensity 8 is enough to even make tombstones move.

History repeats itself
In April 2015, Nepal was struck by a magnitude 7.8 earthquake which caused a reported estimate of 10,600 casualties and severely damaged the city of Kathmandu. "Tingnan ninyo yung nangyari sa Nepal, kahit early pa ng 100 years yung estimated time ng malaki nilang earthquake, biglang tumama yung major event na yun,” reminds Mabel. "Papasok na tayo sa estimated 400-year cycle ng major earthquake kaya dapat lagi tayong handa sa mga pwedeng mangyari."

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Phivolcs have been preparing themselves, as well as the public, for the Big One. Early last year, they released the Valley Fault System (VFS) Atlas—a book with numerous maps that show the fault lines that transverse a large portion of Metro Manila.

The VFS Atlas would change how the Philippines understands and prepares for earthquake-related hazards.

"Hindi namin inaasahang ganito kalaki yung impact ng launching ng Atlas," says Mabel Abigania, one of the five mappers of the ATLAS and coastal studies expert. "It was only when we got a recognition from the Phivolcs director Renato (Solidum Jr.) and started getting attention from the media. Kinabukasan babad kami sa phone calls, nagtatanong, 'Tatamaan po ba kami ng fault?'"


The West Valley Fault has moved four times in the past 1,400 years, which has led to the approximation that it will move once again soon. The last major earthquake from the WVF was in 1658.

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Phivolcs already recognized that there was an active fault under Metro Manila since the early '90s. In the early 2000s, a 1:10,000 (1cm = 100 meters) scale map was produced from the previous scale map 1:50,000 (1cm = 500 meters). In 2012, Phivolcs, with the Department of Science and Technology (DOST), revisited the VFS as one component of the project "Enhancing Greater Metro Manila Areas (GMMA) Institutional Capacities for Effective Disaster/ Climate Risk Management towards Sustainable Development," or the GMMA-READY Project, supported by the United Nations Development Programme and the Australian Agency for International Development. The five geologists then spent two years mapping the entirety of 110 miles worth of landforms—the West Valley Fault 100 Miles, and the East Valley Fault 10 Miles.

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"Kahit kaming lumilinya lang sa earthquake-related studies kailangan din tumulong para mapabilis yung proseso," says Mabel. "Pagdating sa ground ruptures, si Kat (Papiona, Environmental Sciences and Fault Studies Specialist) yung expert doon. Kapag umangat yung coast, katulad nung nangyari sa Bohol, ako (Mabel) naman yung na-train doon. Kahit si Kat yung nagli-lead ng mapping, nate-train din yung mga mata ng mga hindi talaga specialist doon, katulad ko, at natuto rin kami kung paano mag-interpret ng mga different land formations."

"Nakakatulong din na nakaka-collaborate namin yung mga international geologist dahil sila mismo, interested aralin yung mga fault natin,” Kat adds.

The aftershock
The general public can still feel the effects of the VFS Atlas launch. Several establishments, schools, and local communities throughout Metro Manila have contacted Phivolcs to gain knowledge about how they can prepare for the 7.2 magnitude quake that will hit Metro Manila eventually. "Meron pa rin kaming tie-ups with Quezon City LGUs for identifying fault points that go through places with informal settlers," says Mabel.

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"May event kami, yung Walk-the-Fault, sinasamahan namin yung mga LGU's representatives para ituro kung mga tina-transect ng fault. Phivolcs mappers walk with city/community representatives through their city, showing them where the fault line is located and warning the owners of transected establishments and homes. The LGUs are the ones responsible for placing their own markers once the mappers have shown them where the line transects their area.

FHM tried to interview a few homeowners about how they reacted when they were informed that their homes were transected by the fault—but no one was willing to be interviewed in fear that it might devalue their property if they tried to sell it in the future.

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Support from private establishments has never been this widely received by the geological community in their mission for disaster prevention. "May time nung early '90s na hindi makapasok yung members namin sa subdivisions dahil hindi naniniwala yung mga tao na great threat talaga yung fault sa kanila. Parang sinasabi ng mga tao, 'Ah, ginagawa lang yan ng Phivolcs para mag-devalue yung property.' Ngayon, ang ikatutuwa namin, kahit mga private subdivisions, proactive na sila with their properties' safety. Mabe-verify na namin ngayon kung dinadaanan talaga ng fault yung lugar nila o hindi,” says Mabel.

The University of the Philippines National Institute of Geological Sciences (UP-NIGS) recently launched their own version of the Atlas by plotting the fault line on the much easier to read, Google Maps. But the mappers themselves are hesitant to actually recommend the plotted Google Earth map to the public because "gumagalaw yung linyasumasakabilang-bahay yung fault," as Mabel puts it. The mappers themselves put five-meter buffer zones, where no structure should be built, along the points transected by the fault but the relative error of the plotted Google Earth Map reached up to 20-meters which caused confusion among many Filipinos. "Kasi kung kaya namin ilagay nang ganun kadali sa mobile apps accurately yung fault line, sana matagal na naming ginawa pero since alam nga naming na-o-offset yung linya. Madugo kasi yung process ng review from our base drawings to the plotting—mga two years din yun,” Mabel informs us.

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The shared responsibility
"Pero siguro kailangan din ng magturo ng basic map reading sa mga schools dito dahil sa ibang bansa, kayang-kaya naman nilang magbasa ng ganitong klaseng mga map," says Kat. "Maraming hindi nakaka-appreciate nung mismong map dahil hindi nila kayang basahin yung mapa. Gusto nilang ilagay namin sa Google Earth Maps para raw kapag ni-zoom-in nila pati yung streets nakikita kasi hindi nila mahanap kung nasaan yung mga bahay nila,” adds Mabel.

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A PDF version of the Atlas is available for download after registering on the Phivolcs website. The people at Philvolcs encourages the people to ask them about how to properly read the map so they prepare accordingly, any earthquake hazard prevention strategies that they might want to adapt. They also encourage them to ask any questions they have want answered to make them feel less anxious about the earthquake. "Ang takot ng mga tao ay kung transected yung bahay o establishment nila pero sa totoo lang, lahat naman ng Metro Manila malulumpo kapag tumama 'tong binansagan nilang 'The Big One.' Ang preparedness dapat from individual to community level dapat alam nila kung saan sila pupunta, kung may designated evacuation area ba yung barangay nila; at iba pang earthquake procedure dahil walang makakasabi kung kailan 'to mangyayari,” Mabel reminds.

When "The Big One" finally does happen, Phivolcs predicts that their system would probably shutdown for 30 minutes to an hour before they can copy it to a mirror station at some other province. Right now, the only one compatible is at Cavite but they believe that that one will be affected by the earthquake as well so they're setting up one in Cebu and one in Davao so people will still have access to the information they need.

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The rescue will probably come from neighboring provinces because most of the rescue teams here will probably be concerned with their own families’ safety, "Yung usapan namin, unahin munang i-secure yung families namin tapos diretso ng office para makatulong sa ibang tao,” says Mabel.

Director Renato Solidum Jr. of Phivolcs has a few comforting words to heed in a time where such a threat is imminent. "I can live with this fault because I am aware and I am prepared."


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