Work is underway to identify in Metro Manila’s neighboring areas the safe open spaces (SOSs) where people can run to and assemble when the “Big One” strikes.
The “Big One” is a worst-case scenario of an earthquake from the West Valley Fault, a 100-kilometer fault that runs through six cities in Metro Manila and nearby provinces. A tsunami is also foreseen in the scenario set by the Philippine Institute of Volcanology and Seismology (Phivolcs).
The National Mapping and Resource Information Agency (NAMRIA) already identified and mapped SOSs in Metro Manila and began to do the same for neighboring areas as the West Valley Fault (WVF) runs through six cities in Metro Manila and nearby provinces. A tsunami is also foreseen in the scenario set by the Philippine Institute of Volcanology and Seismology (Phivolcs).
NAMRIA supervising remote sensing technologist Josephine Ferrer said the agency is already collecting the latest available high-resolution images of the neighboring areas to be used in identifying potential SOSs there.
“We’ll base our interpretation of open spaces on those images,” she said.
She said concerned local government units (LGUs) will verify if the identified open spaces still exist.
NAMRIA is supposed to be undertaking an ocular inspection of potential SOSs but came up with such work arrangement instead due to health risks and mobility restrictions arising from continuing onslaught of novel coronavirus disease 2019 (Covid-19) pandemic, she noted.
She said Phivolcs will still help NAMRIA identify SOSs in Metro Manila’s neighboring areas.
SOS is a vacant land at least 200 square meters in size, free from earthquake-related hazards and located outside a radius 1.5 times the height of adjacent or surrounding buildings, she said.
Aside from being an assembly area when earthquakes strike, she said SOSs may also serve as temporary shelter, rescue and medical stations, food and water depots, as well as other emergency services.
Phivolcs’ assessment about WVF is raising the urgency for identifying and mapping the SOSs as WVF is already ripe for movement.
Data shows WVF already moved four times in the past 1,400 years, Phivolcs noted.
Phivolcs said such indicates WVF moves at an approximately 400-year interval, the last being around 1645.
Ferrer said NAMRIA already introduced its SOS mapping project to LGUs of Metro Manila’s neighboring Cavite, Laguna, Batangas and Rizal provinces in Region IV-A (Calabarzon) and Bulacan province in Region III (Central Luzon).
“Those LGUs are willing to cooperate with us on the project,” she said.
She said such LGUs are familiar with respective areas so these can easily verify if open spaces NAMRIA will identify are still existing or not anymore.
The 2002-2004 “Study for Earthquake Impact Reduction for Metropolitan Manila” warned that a magnitude 7.2 WVF-triggered earthquake can kill around 34,000 people, injure some 114,000 persons, partly damage an estimated 340,000 residential structures and cause the collapse of about 170,000 houses.
“Fire will break out and burn approximately 1,710 hectares and a total of 18,000 additional persons will be killed by this secondary disaster,” the study also said.
Infrastructure and lifelines will suffer heavy damage as well, the study continued.
Ferrer said in 2019, NAMRIA concluded its Metro Manila SOS mapping project. Metro Manila then had 5,720 SOSs, she noted.
“Those SOSs are the open spaces not prone to tsunamis, liquefaction and landslides,” she said, referring to earthquake-related hazards.
She cited the need to update Metro Manila’s list of SOSs since several of these are privately owned and may have been already developed for commercial and non-commercial purposes.
Source: Philippines News Agency
