MANILA, Philippines— While some believe that the taller buildings face more danger from the “Big One” — a powerful West Valley Fault earthquake — the Philippine Institute of Volcanology and Seismology says otherwise.
Phivolcs Director Renato Solidum Jr. said low-rise and and mid-rise buildings in Metro Manila are more at risk from the anticipated high intensity ground shaking caused by movement on the West Valley Fault.
“If you look at things, there is a perception that is common in most people that the taller, the building the more dangerous it is,” Solidum said in a February 2017 televised interview on ANC after the Surigao quake.
“Well, if you look at the reality, the low-rise and mid-rise buildings in Metro Manila can be affected more by the movement of the West Valley Fault because of the fact that these structures... Since these are short, are light and an earthquake occurring nearby... ground shaking fast that would favor more of the lighter meaning the shorter building than tall ones which are heavy,” he added.
Solidum also explained that taller houses and buildings were only built recently and benefit from modern construction technology. He added that Philippine law is very strict on high-rise buildings, making those safer if they complied with the National Building Code.
The Phivolcs director said that developers or engineers should always follow the most recent building code.
“The newer code, the better the design,” he said, adding that evaluation of establishments should be done from time to time.
The National Building Code dates back to 1977 but the Implementing Rules and Regulations were updated in 2005, according to the Department of Public Works and Highways website.
Solidum said inspections of establishments should be done at the start of every year as he warned that earthquakes cannot be predicted and it is best for the public to prepare with the help of professionals.
According to Solidum, the agency has been conducting an information campaign on the West Valley Fault and the Building Code since 2004. He said they also have been sharing the right models for buildings to follow.
“Building code should be followed by engineers. If this would be followed as dictated by the law and by ethical principles, then one can be assured that if you follow the code then this can resist strong Intensity 8 shaking,” he concluded.
Under the Phivolcs Earthquake Intensity Scale, Intensity VIII quakes are "Very Destructive", where "many well-built buildings are considerably damaged."
Phivolcs has identified the cities of Quezon, Makati, Muntinlupa ,Pasig and Taguig as among those that fall along the West Valley Fault.
Infographic: West Valley, East Valley Fault barangays