A magnitude 7.2 earthquake like the one that devastated Bohol last month could kill as many as 35,000 people if it struck Metro Manila, according to an official of the Philippine Institute of Volcanology and Seismology (Phivolcs).
Ishmael Narag, officer-in-charge of Phivolcs’ Seismological Observation and Earthquake Prevention Division, cited figures from a study made by the Japan International Cooperation Agency (Jica), Metropolitan Manila Development Authority (MMDA) and Phivolcs in March 2004.
The study described the consequences if a 7.2-magnitude quake hit Metro Manila.
It estimated that around 34,000 people will die and 114,000 others will be injured; 170,000 residential houses will collapse and 340,000 houses will be damaged, and hundreds of fires will be ignited by the quake.
Speaking at the Bulong Pulungan news forum on Wednesday, Narag said that the Department of Public Works and Highways (DPWH) has been consistently checking the structural integrity of all public buildings in the metropolis, it is still far from the “ideal” stage of earthquake preparedness.
He said all the preparations of the government will be useless if private structures which represent 60 percent of all existing buildings in Metro Manila will fail during the “big one”.
The “big one” is how Philvolcs refers to a strong earthquake triggered by movements in the West Valley Fault.
The fault, which runs from the Sierra Madre down to Laguna crossing Quezon City, Marikina, Pasig, Makati, Taguig, and Muntinlupa, is capable of generating a magnitude 7.0 to 7.4 temblor.
Narag said that based on previous studies the West Valley Fault has movement intervals of 400 to 600 years and the last quake along the fault was in 1658.
“So the question is not if the big one will happen, because it will definitely occur, the question should be when and if we are ready for it,” he said.
Narag said the study was conducted nearly 10 years ago using the year 2000 census, and because Metro Manila’s population and structures have increased the damage and casualties would be bigger.
Around 10 percent of hospitals, schools, police stations and government building will be destroyed, while 25 percent will sustained moderate damage.
Of 1000 medium rise buildings (10-30 stories) 11 percent will collapse and 20 percent will sustain minor damage.
Two percent of high rise buildings (30-60 stories) are expected to collapse while 12 percent will sustain moderate damage.
Cities that are expected to suffer most number of residential building damage and human loss are Marikina, Manila, Pasig, Pateros, Taguig.
Narag said many private structures were built without consulting civil engineers.
The earthquake in Bohol and left more than 200 people dead and damaged centuries old churches. JEFFERSON ANTIPORDA