For three days in a row, the Philippines has experienced moderately strong earthquakes in various parts of the country. Varying from intensity 5 to intensity 6 in magnitude, the country experienced earthquakes in the Bicol Region, Ilocos region and just tonight at 1830H, in the Southern Tagalog Area of Mindoro/Lubang Island.
The quake was felt at intensity 3 in Metro Manila.
While no injuries were reported, it sends a chilling reminder to everyone about the expected “Big One” to hit the National Capital Region of Metro Manila anytime soon. Metro Manila after all sits on top of several Faults or Valley Fault Systems (VFS), some of which run right at the heart of the metropolis.
A study conducted jointly by the Japan International Cooperation Agency (JICA) and the Metropolitan Manila Development Authority (MMDA) in 2002 – 2004 showed that a rupture along the VFS could result in a 7.2 magnitude earthquake, which could kill up to 33,000 people and injure more than 100,000 if adequate preparations are not made.
Metro Manila today comprises 13 cities and four municipalities with a total population going up by 2.5 times in the last 30 years to the present 10 million.
It is estimated that by 2015, about 25 million people will be living in this National Capital Region, including rapidly urbanized areas of Laguna, Cavite and Rizal Provinces.
As a result of rapid urbanization, reducing vulnerability to potential natural disaster, through raising awareness of people and organizations, developing a comprehensive disaster management plan and strengthening networks of national and local governments as well as communities, is crucial to safeguarding safety of those who live and operate in Metro Manila.
In and around Metro Manila, numerous earthquake sources exist, such as Valley Fault System (VFS), Philippine Faults, Lubang Faults, Manila Trench and Casiguran Faults. Among these, VFS, which transects the JICA Study area, is considered to cause the largest impact to Metro Manila area if it will become active. Recent studies show that VFS has ruptured twice to four times in the last 1400 years with a return period being approximately less than 500 years. And since no event of a major earthquake has been known along West Valley Fault since the 16th Century, active phases of the Valley Faults may be approaching. Results of many researches indicate that an estimated magnitude will be around 7 or higher.
Citing history of the recent earthquakes’ sources, Philippine Institute of Volcanology and Seismology (PhiVolcS) Chief Renato Sulidum, Jr. predicts that the VFS in and around Metro Manila are most likely to be active soon.
Which now brings us to the all important question : ARE WE READY FOR THE BIG ONE?
Several Volunteer Organizations such as the MCFRVI have been continually discussing and plotting response scenarios, should the Big One hit, but the alarming reality is, basing from the response shown by the government from Typhoon Ketsana (a.k.a. Ondoy), WE ARE NOT READY!!!