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Prepare for the Worst

Sunday, February 26, 2017 02:39 AM    Views : 343by:Focus Features
PHIVOLCS Director - Renato U. Solidum, Jr.

As Filipinos brace for the likely possibility of "The Big One." awareness and understanding are the start. According to Solidum, "For all of us to prepare, we have to convince ourselves that we will be affected by it. Our families and our communities will be affected and we have to do something about it."

PREPARE FOR THE WORST
‘Disaster imagination' is the key to readiness, says the country's chief earthquake expert.

At the headquarters of the Philippine Institute of Volcanology and Seismology (PHIVOLCS) inside the UP campus in Diliman, director Renato U. Solidum, Jr. gives The Manila Bulletin a tour of what is basically the country's main nerve center for phenomena both seismic and volcanic, a specially designated room where seismologists monitor real-time occurrences of the likelihood of earthquakes and volcanic eruptions.

One section features an array of large monitors that show a mild tremor that manifested briefly, an intensity so low but recorded permanently by the most precise of instruments. Another room would feature footage from cameras mounted near the most active volcanoes of the country.

Solidum is proud to say that many of those technologies in PHIVOLCS were developed by Filipino scientists, our very own seismologists, and that they regularly have visitors from other countries who check out what PHIVOLCS has to offer to the scientific world. After all, Solidum's staff have to be on their toes 24/7: the Philippines, part of the Pacific Rim of Fire, has a very active environment prone to earthquakes and volcanic eruptions. As of this writing, a mild intensity earthquake just struck Davao City, just two weeks after the one that struck Surigao del Norte (magnitude 6.7) that left six people dead.

But what would happen if an earthquake of the same intensity occured right in the heart of the capital, or any major city for that matter?

Mind-shattering Scenarios

Solidum reveals that from 2002 to 2004, PHIVOLCS and agencies like the Metro Manila Development Authority (MMDA), and Japan International Cooperation Agency (JICA) studied 18 earthquake scenarios. Of those 18 scenarios, they selected two they considered as worst-case.

"One is a movement of what we call the Manila Trench, an earthquake generator offshore of West Luzon that can generate a magnitude 7.9 earthquake," he explains. This one can generate tsunamis that can reach many shorelines facing western Philippines. "But the shaking that it will cause in Manila will not be as severe as another scenario we use now for Metro Manila."
He was referring to the other one, one more dangerous and more catastrophic in scale—a magnitude 7.2 earthquake generated by the West Valley Fault.

"It will generate an intensity 8 shaking in [all of] Metro Manila, part of Bulacan, maybe south of Pampanga, western Rizal, northern Cavite, and northwest Laguna," he says.

But that is just the beginning, according to him. If that intensity 8 shaking occurs at the shallow level, around 13 percent of the residential buildings from one to 10 storeys, 10 percent of public buildings, eight to 11 percent of mid-rise buildings, and two percent of high-rise buildings will suffer heavy damage—or even collapse!

"Around 33,000 people may die in Metro Manila alone if the earthquake happens in the evening. Additionally, there will be more than 100,000 who will be seriously injured. Additional death can be caused by fire. Infrastructure will be severely damaged—roads in some areas, bridges might be affected. There will be momentary losses in terms of water supply, electricity. Even communication systems can be affected," he declares.

These are just some of the things that can happen and that scenario was termed by the media as "The Big One." He is confident, however, that unlike the 2007 earthquake in Haiti, an earthquake in Manila may have many of our buildings and structures withstanding it, so long as the buildings don't stand on the fault line.

"We have a good building code. In fact, even in the 1990 earthquake and even in some of the more recent earthquakes in some places of the Philippines, there are more buildings that are left standing than collapsed. We can lessen the impact if houses and buildings are constructed properly or made to standard, even if these were constructed before using the old code, to make sure they are upgraded to the current code," he shares.

A Share of the Same Disaster

Solidum adds that this phenomenon would happen not only in Metro Manila. "Other areas in the Philippines also have their own ‘Big Ones' or earthquake scenarios. As to when earthquakes will happen in some areas, we don't exactly know the time," he explains. "It will not affect the whole country, just like what happened in northern Mindanao—the magnitude 6.7 earthquake that mainly affected Surigao del Norte also shook islands as far away as 250 km from the epicenter. Basically, the entire country sits on a series of plates that are constantly in tension with each other."

Well, not entirely, as only one island in the country has been spared from all of this—Palawan.

"In the current earthquake history of the Philippines, and also based on the locations of the earthquakes, only Palawan will not be shaken severely and will not be affected by a strong earthquake. The rest of the country has been affected in the past and can be affected in the future," he adds.

Different Quakes, Different Takes

Based on Solidum's assessment, the impact of the disaster was minimized in Surigao.

"What happened in Surigao? There was no mid-rise [structure]. The buildings there were no taller than 10 storeys. We had warned those living along fault lines to move their houses. So if you notice, the most prominent structure damaged was an old bridge, since it was on a fault line," he explains.

He dismisses notions that those living or working inside high-rise structures would be most prone to danger. "The movement of the ground or the earthquake will affect different structures in different ways. If the earthquake is near the fault, the shaking of the ground will be fast. Low- to mid-rise buildings will move more than the tall buildings simply because of their height (they are lighter). But if the epicenter is already very far, the ground movement, which was originally fast, would become slow—from high frequency to low frequency. Then you will see the taller buildings sway more than the shorter ones. This means that whatever height of the buildings that we need to construct, we need to make sure that this follows the standards of our building code. We use the right materials, the right design and we do the right workmanship on them," Solidum says.

What Could Happen

With the Filipinos' experience with many disasters like earthquakes, and with the advances in science and engineering, should we expect fewer casualties in time?

"As you noticed, many people still get affected. Many people die, they get injured. We ask why there were deaths during the Bohol earthquake in 2013. The common answer would be, ‘They were not prepared.' But why were they not prepared? Maybe they didn't know that their area would be hit by an earthquake. Maybe they knew in general but they didn't know what specific areas would be affected. Maybe they knew, but they didn't know the impact of the event—how many houses would be damaged, how many people would die, how many would be injured. Better yet, would they be affected by it? Or maybe they knew the scenario, but they didn't know how to prepare; or if they prepared, they didn't know if it was the appropriate [preparation] to the scale of the disaster that would happen. So essentially, these are some of the reasons."

Filipinos, according to Solidum, need to have what he calls:

"disaster imagination." "For me, the key to preparedness is disaster imagination—imagination of what could happen before it happens; imagination of what we can do so that what we foresee in the future will not really happen," he explains.

As Filipinos brace for the likely possibility of "The Big One," awareness and understanding are the start. According to Solidum, "For all of us to prepare, we have to convince ourselves that we will be affected by it. Our families and our communities will be affected and we have to do something about it."

Source: http://focusfeature.mb.com.ph/2017/02/26/prepare-for-the-worst/

S & T Trivia

" Filipino astronomers Edwin Aguirre and Imelda Joson discovered Asteroid 6282 (called Edwelda after their first names), an asteroid orbiting the sun between Mars and Jupiter. "

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