Four earthquakes hit Mindanao within a two-week period starting in October – a magnitude 6.3 on October 16, a magnitude 6.6 on October 29, a magnitude 6.5 on October 31, and a magnitude 5.5 on November 1. At least seven people were killed in the first quake, nine in the second, and five in the third, mostly from being hit by falling debris.
The four earthquakes remind us once again that our country is in the Pacific “Ring of Fire” which is not only dotted with active volcanoes but also lies above major tectonic plates grinding against each other, building up immense tensions that, when suddenly released, cause the surface lands to rumble in deadly earthquakes.
Where two plates grind against each other, there is what scientists term a fault. One of the biggest faults in the Philippines is the West Valley Fault, running from Bulacan down through eastern Metro Manila, to Cavite. It is predicted to cause a major earthquake in Metro Manila any time soon, which is why we have been holding annual exercises preparing the people, particularly, our school students, to be ready for the “Big One,” a magnitude-7.1 earthquake.
There are records of earthquakes in the Philippines as far back as the 17th century during the Spanish colonial period. One in 1645, with a magnitude of 7.5, killed some 600 people and damaged the Manila Cathedal and other churches in Manila and nearby provinces. An earthquake in 1863 completed the destruction of the cathedral, along with the Ayuntamieno (city hall) and the Governor’s Palace and much of the rest the city, forcing the governor-general to move his residence to Malacanang three kilometers away along the Pasig River.
During the American period in the 20th century, the strongest earthquake was a magnitude 8.3 in 1918 that shook southern Philippines, followed by a tsunami that killed 52. A magnitude 8 struck in 1976, followed by a devastating tsumami from the North Celebes Sea that hit the coast of southern Mindanao. In 1990, a magnitude 7.7 hit Luzon, causing widespread destruction in Baguio, Dagupan, and Cabanatuan cities, leaving 1,621 dead.
These are only the most powerful of the scores of earthquakes recorded in Philippine history. Thus the three recent Mindanao earthquakes that struck within a two-week period should not be much of a surprise.
But they remind us of our constant need to be ready at any time for an earthquake, with the most obvious need being to protect oneself from falling debris, the most common cause of death. Thus school children are told to cover their heads, even with only a book, as they make their way out of a shaking building.
There is some concern about the many high-rise buildings that have been built all over the country. Several probes by various government agencies have been scheduled to determine if these buildings have been constructed with the required steel bars to make them more capable of withstanding a strong earthquake.
The four successive Mindanao earthquakes are a reminder that earthquakes are an inevitable part of life in the Philippines. With government ensuring that our buildings are properly reenforced and our people trained to protect themselves, we should be able to carry on in the face of this threat to life in our country.