The big earthquake that struck Leyte last Thursday caught most people unprepared. Tremors of 4 to 5 magnitude are common enough in our country. The one that hit Leyte was a magnitude 6.5 and initial reports said three were killed and 72 injured from falling hollow blocks in buildings that collapsed in Kananga and Ormoc City.
Earlier this year, a 6.7 hit Surigao in northeast Mindanao in February, followed by a 5.5 in Batangas in southern Luzon in April. Then a powerful 7.2 struck Sarangani at the southern tip of Mindanao in May. Now after about two months, Leyte in eastern Visayas has been shaken by this 6.5 that has also caused damage in nearby Cebu province and knocked out the power in Bohol, Southern Leyte, Biliran, and Samar.
This latest earthquake should renew and strengthen the state of alert that has long been issued for the people of Metro Manila where the Metro Manila Development Authority (MMDA) has scheduled a four-day quake drill on July 14-17.
We had a “Shake Drill” in June last year that also included the nearby provinces of Bulacan, Cavite, Rizal, and Laguna.
The quake drill has become an annual affair to prepare the people of Metro Manila for what the Philippine Institute of Volcanology and Seismology (Phivolcs) fears will be a magnitude-7.2 earthquake that could come at any time. This fear arises from the existence of the West Valley Fault that begins in Bulacan, cuts through Metro Manila, and continues on to Southern Luzon. This underground Fault is said to move about every 400 years, causing a massive earthquake, and the last time it moved was 357 years ago.
The Phivolcs fears that when the West Valley Fault gives way, it will cause a magnitude-7.1 earthquake that could damage many buildings in Metro Manila. The more recent buildings here were built with the needed structural strength and stability, but there are hundreds of older buildings all over the area that pose tremendous danger to the people of this highly populated region.
The government and private aid organizations must move quickly to help the people of Leyte who just went through the harrowing experience of a very strong 6.5 earthquake. It should help keep the rest of the country on alert for we are an earthquake prone country.
But the greatest state of alert and readiness must be in Metro Manila due to the West Valley Fault and the Phivolcs warning that the “Big One” with a magnitude of 7.1 could come at any time, because of the recorded history of that fault moving about every 400 years.