EDITORIAL - The Big One in Mindanao?

Will the so-called Big One hit Mindanao first before Metro Manila?

This is the question on everyone’s mind as Mindanao was struck by powerful earthquakes on Oct. 16, 29 and 31, of magnitudes 6.3, 6.6 and 6.5, respectively. The epicenters were around the Cotabato area and there were hundreds of aftershocks. On July 9 this year, North Cotabato was also rocked by a 5.6-magnitude temblor.

Scientists say Cotabato sits in a seismically active area, with five earthquake faults plus the Cotabato Trench, which can generate tsunamis. Seismologists are trying to determine if this year’s quakes in the same area are connected and a possible prelude to the Big One of at least 7.2 magnitude.

If it happens, it won’t be the strongest to hit Mindanao. In August 1976, movement in the Cotabato Trench generated a magnitude 7.9 quake and a tsunami up to nine meters or nearly 30 feet high in southern Mindanao, leaving over 6,000 people dead and another 2,000 missing, mostly from the tsunami. The Philippine Institute of Volcanology and Seismology reports that Mindanao has been hit by earthquakes of up to magnitude 8 in the previous century.

Mindanao in 1976, however, had fewer people, public works infrastructure and concrete buildings that could collapse from a powerful earthquake. Today, if a magnitude 8 quake strikes anywhere in the country, the death toll is expected to be horrific. A magnitude 7.2 earthquake in Metro Manila – the Big One generated by the Marikina Valley Fault – could leave 35,000 people dead, according to a comprehensive study on earthquake preparedness in the country’s most densely populated region.

Seeing images of buildings in Mindanao collapsing or teetering on the brink, there are calls for ensuring compliance with structural standards in the Building Code. To protect their own lives and property, people themselves should want to ensure the structural integrity of their houses and places of work, education, recreation, worship, commercial and other activities.

In the wake of last Thursday’s temblor, Phivolcs associate scientist Toto Bacolcol reminded the public: “Earthquakes don’t kill people… It’s the collapse of man-made structures, buildings, retaining walls that do.” It’s a warning that must be heeded if the Big One hits – whether in Mindanao or Metro Manila.