Marikina Valley Fault System

MVFS
Site of Special Scientific Interest

A Canlubang Golf and Country Club faultline zone
Location within Metro Manila
Area of Search Metro Manila
Coordinates 0°00′00″N 100°00′00″E / 0°N 100.00000°E / 0; 100.00000
Interest Seismic
Area Marikina City, Rodriguez, Rizal
Notification May 18, 2015

The Marikina Valley Fault System, also known as the Valley Fault System (VFS), is a dominantly dextral strike-slip[1] fault system in Luzon, Philippines. It extends from Dingalan, Aurora in the north and runs through the provinces of Nueva Ecija, Bulacan and Rizal, and the Metro Manila cities of Quezon, Marikina, Pasig, Makati, Parañaque, Taguig and Muntinlupa, and the provinces of Cavite and Laguna that ends in Canlubang.[1]

Fault segments

The fault contains two major segments, known as West Valley Fault (WVF) and East Valley Fault (EVF).

West Valley fault

The west segment, known as the West Valley Fault (WVF) is one of the two major fault segments of the Valley Fault System which runs through the cities of Marikina, Pasig and Muntinlupa of 100 kilometers when the fault moves.[2] and moves in a dominantly dextral strike-slip motion.[1] The West Fault is capable of producing large scale earthquakes on its active phases with a magnitude of 7 or higher.[2]

East Valley fault

The eastern segment, known as East Valley Fault (EVF) moves in an oblique dextral motion within 10 kilometers.[1]


Threat to Manila

Based on kinematic block models that utilize GPS, actual fault geometry, and earthquake focal mechanisms, the West segment of the Marikina Fault was resolved to be almost fully locked, meaning it is currently accumulating and loading elastic strain, at the rate of 10 to 12 mm/yr.[3] The fault possesses a threat of a large scale earthquake with an estimated magnitude between 6–7 and as high as 7.6 [4] within the Manila Metropolitan Area with death toll predicted to be as high as 35,000[5][6] and some 120,000 or higher[5] injured[6] and more than three million needed to be evacuated.[2]


Relief Map of Metro Manila and nearby provinces showing the surface traces of the West and East Valley Faults

References

  1. 1 2 3 4 Rimando, Rolly E.; Knuepfer, Peter L.K. (2004). "Neotectonics of the Marikina Valley fault system (MVFS) and tectonic framework of structures in northern and central Luzon, Philippines". Tectonophysics. Elsevier. 415 (1–4): 17–38. doi:10.1016/j.tecto.2005.11.009.
  2. 1 2 3 "‘Big One’ Is Possible But Metro Is Unprepared". Quezon City, Philippines: Bulatlat. 14 August 2004. Retrieved 2010-02-03. If a major earthquake were to hit Metro Manila today, the devastation would be so big even disaster response authorities cannot simply cope with it. And it even looks like disaster preparedness occupies a low priority among officials down to the municipal level.
  3. ↑ Galgana, Gerald (2007). "Analysis of crustal deformation in Luzon, Philippines using geodetic observations and earthquake focal mechanisms". Tectonophysics. 432 (1-4): 63–87 – via Elsevier Science Direct.
  4. ↑ Nelson, Alan R.; Personius, Stephen F.; Rimando, Rolly E.; Punongbayan, Raymundo S.; Tungol, Norman; Mirabueno, Hannah; Rasdas, Ariel (2000). "Multiple Large Earthquakes in the Past 1500 Years on a Fault in Metropolitan Manila, the Philippines". Bulletin of the Seismological Society of America. Seismological Society of America. 90 (1): 84. doi:10.1785/0119990002.
  5. 1 2 Ubac, Michael (20 June 2009). "UN to Metro Manila: Ready for Big One?". Inquirer.net. Philippine Daily Inquirer. Retrieved 2010-01-30. Is Metro Manila prepared for the Big One?
  6. 1 2 "Big earthquake in Marikina Valley fault line?". Pinoymoneytalk.com. Retrieved 2010-01-30. The United Nations is advising the Philippines to be ready for an upcoming big earthquake. A quake with a magnitude of 7 or higher on the Richter scale is sure to hit Metro Manila, they say, but the bigger question is when exactly this will happen.
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