Tuesday, March 15, 2011

Earthquake epicentered near Lubang Island


Only hours after the recent China and Japan earthquakes, a moderate earthquake hit Mindoro (magnitude 5), on March 11, with its epicenter traced at 15 km east of Lubang Island at a deeper 101 km, the Philippine Institute of Volcanology and Seismology said.

No one would and could venture into giving serious warnings as to when the next earthquake will occur and where. We could only look back and review what had occured in the past. Extract from my previous post, "Philippine Segment of Pacific Ring of Fire Roaring", 1/18/10 follows:

In June of 2006, Philvocs warned that an earthquake with a magnitude 7.2 on the Richter Scale “is overdue” and could hit the Philippines soon affecting at least 38 percent of all residential buildings in Metro Manila. “The last strong quake to hit us was in 1994. With time, the possibility of being hit by a strong earthquake is increasing”. 90 strong quakes had been recorded here over the last 400 years, or a statistical average of one major quake every four to five years. (manilastandardtoday.com 6.27.2006)

But no strong quake has been recorded for a decade after the 1994 quake in Mindoro that killed at least 78 people and caused panic in Gasan when hit by a minor tsunami after the quake.

(USGS Map showing Lubang Fault between Mindoro and Marinduque)

Marinduque quake

On October 20, 2006, Philvocs reported a 5.3 magnitude earthquake in Marinduque around 10:30 p.m. with tremors reaching as far as Tagaytay and Quezon City.

A second earthquake struck around 1:27 a.m. the next day with the epicenter located 35 kilometers south and 89 degrees west of Boac, Marinduque. The Lubang and Marinduque faults were identified as the sources of the earthquake. (pinoyexchange.com/forums)



Philvocs Director Renato Solidum,Jr. then reported that the Marinduque quake’s epicenter was traced to the eastern segment of the Lubang Fault located offshore between Mindoro island and Marinduque. Five major aftershocks and more than 700 minor aftershocks were recorded.

The quake caused no damage to property but sent many residents in Marinduque to panic. Solidum then said that despite the earthquake at the Lubang Fault, people should remain alert against "the big quake." He said there is no way to predict where or when the big quake will occur.

"Lubang Fault does not generate that powerful a quake. But the Philippine Fault Zone is one of the longest, and some faults had already moved, like the one in Central Luzon in 1990 and the one in Masbate in 2003," he said. (gmanews.com 10.26.06)



USGS Map showing earthquake density.



(Markers that show epicenter of recent earthquakes)