EDITORIAL - Big Ones

Barely two days after a 7.4-magnitude earthquake struck Surigao del Sur, the province was again rocked by another powerful temblor. While slightly weaker, a magnitude 6.8 earthquake is still strong enough to cause death, injury and substantial destruction.

Scientists in the Philippine Institute of Volcanology and Seismology likened the 7.4-magnitude quake to the “Big One” that Phivolcs has been warning about in Metro Manila. Emanating from the 100-kilometer West Valley Fault, the Big One is estimated at magnitude 7.2 in the Metropolitan Manila Earthquake Impact Reduction Study conducted nearly a decade ago. But according to the study, even a 30-second quake of that magnitude in the country’s most densely populated region can leave up to 34,000 people dead, 90 percent of them from being crushed in collapsed structures or suffocated or burned in fires.

The study conducted by the Japan International Cooperation Agency together with the Metropolitan Manila Development Authority projected heavy damage or destruction of about 10 percent of public buildings and 170,000 houses. Seismologists have warned that the strongest earthquakes in the West Valley Fault had recurring intervals of 400 to 500 years. It’s been 365 years since the last major quake emanating from the fault in 1658.

Disaster response and mitigation agencies as well as many private property developers and public works contractors are heeding the warnings, although much can still be done by way of preparedness for the worst. But this is in the National Capital Region. Many other places across the archipelago, which sits along the seismically active Pacific Ring of Fire, are just as vulnerable to powerful earthquakes, as Surigao del Sur is now seeing. Preparedness and mitigation measures, however, are much less outside the NCR.

Just last Nov. 17, a magnitude 6.7 earthquake struck off Sarangani, leaving at least nine people dead. In Surigao del Sur, the magnitude 7.4 earthquake left a pregnant woman dead, at least four people injured and nine others missing. Around 600 aftershocks with magnitudes ranging from 1.4 to 6.2 were recorded before the second powerful earthquake struck.

On Oct. 15, 2013, a