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Marikina Valley fault system
Lower and upper fault plain along the West Valley Fault in Carmona, Cavite
Map of the Marikina Valley fault system, showing relative motion and deformation
Etymology	Marikina
Named by	Philippine Institute of Volcanology and Seismology
Year defined	2010
Coordinates	14°38′N 121°5′E / 14.633°N 121.083°E / 14.633; 121.083
Country	Philippines
Region	Central Luzon, Metro Manila, Calabarzon
Cities	West: Marikina, Quezon City, Pasig, Taguig, Muntinlupa, General Mariano Alvarez, Carmona, Silang, San Pedro, Biñan, Santa Rosa, Cabuyao, Calamba East: Rodriguez, San Mateo
Characteristics
Segments	West Valley Fault, East Valley Fault
Length	146 km (91 mi)
Displacement	10–12 mm (0.39–0.47 in)/yr
Tectonics
Plate	Philippine Sea plate and Sunda plate
Status	Active
Earthquakes	1658, 1771
Type	Strike-slip fault
Movement	Dextral
Age	Gelasian
Orogeny	Luzon-Mindoro-Palawan Orogeny
Volcanic arc/belt	Macolod Corridor

The Marikina Valley fault system, also known as the Valley fault system (VFS), is a dominantly right-lateral strike-slip fault system in Luzon, Philippines. It extends from Doña Remedios Trinidad, Bulacan in the north, running through the provinces of Rizal, the Metro Manila cities of Quezon, Marikina, Pasig, Taguig and Muntinlupa, and the provinces of Cavite and Laguna, before ending in Canlubang in the south.

Fault segments

The fault contains two major segments: the West Valley Fault (WVF) and the East Valley Fault (EVF).

West Valley Fault

The western 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, Quezon City, Pasig, Taguig and Muntinlupa in Metro Manila and moves in a dominantly dextral strike-slip motion. The West Valley Fault segment extends from Doña Remedios Trinidad to Calamba and is 129.47 kilometers (80.45 mi) long.

The West Valley Fault is capable of producing large-scale earthquakes during its active phases with a magnitude of 7 or higher.

East Valley Fault

The eastern segment, known as the East Valley Fault (EVF), moves in an oblique dextral motion. It extends about 17.24 kilometers (10.71 mi) from Rodriguez to San Mateo in the province of Rizal.

Threat

Based on kinematic block models that utilize GPS, actual fault geometry, and earthquake focal mechanisms, the western segment of the Marikina Valley fault system was resolved to be almost fully locked, meaning it is currently accumulating and loading elastic strain at a rate of 10 to 12 mm/yr. The fault poses a threat of a large-scale earthquake with an estimated magnitude between 6–7 and as high as 7.6 to Metro Manila and surrounding provinces, with a death toll predicted to be as high as 35,000 and some 120,000 or higher injured and more than three million needed to be evacuated.

There are 99 private villages and subdivisions inside 80 barangays traversed directly by the fault, and it endangers 6,331 buildings in a span of 2,964.10 square kilometers (1,144.45 sq mi), where the majority are houses with 19 schools included in the list.

References

1. ^ Malicdem, Ervin (August 16, 2017). "Barangays and Buildings Traversed by the Valley Fault System". Schadow1 Expeditions. Retrieved September 7, 2017. There are about 6,331 structures that are directly above the Valley Fault System within a 10-meter proximity which would be in potential danger of destruction once the slip-fault moves. This sums up to an area of 2,964.10 square kilometers in danger of collapse.
2. ^ 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. 415 (1–4): 17–38. doi:10.1016/j.tecto.2005.11.009.
3. ^ "'Big One' Is Possible But Metro Is Unprepared". Quezon City, Philippines: Bulatlat. August 14, 2004. Retrieved February 3, 2010. 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.
4. Galgana, Gerald (2007). "Analysis of crustal deformation in Luzon, Philippines using geodetic observations and earthquake focal mechanisms". Tectonophysics. 432 (1–4): 63–87. Bibcode:2007Tectp.432...63G. doi:10.1016/j.tecto.2006.12.001.
5. 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. 90 (1): 84. Bibcode:2000BuSSA..90...73N. doi:10.1785/0119990002.
6. ^ Ubac, Michael (June 20, 2009). "UN to Metro Manila: Ready for Big One?". Inquirer.net. Philippine Daily Inquirer. Retrieved January 30, 2010. Is Metro Manila prepared for the Big One?
7. ^ "Big earthquake in Marikina Valley fault line?". Pinoymoneytalk.com. June 20, 2009. Retrieved January 30, 2010. 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.
8. Malicdem, Ervin (August 25, 2017). "LIST: 99 Villages and Subdivisions Traversed by the Valley Fault System". Schadow1 Expeditions. Retrieved September 7, 2017.

External links

• Valley Fault System (VFS): Marikina Quadrangle – Philippine Institute of Volcanology and Seismology
• High resolution West Valley Fault maps launched – Rappler
• PHIVOLCS FaultFinder – This web app is a product of the joint collaboration between PHIVOLCS, DOST, GSJ, AIST. It was developed by Dr. Joel C. Bandibas of GSJ with the cooperation of the research and development personnel of PHIVOLCS.
• Media related to Marikina Valley Fault System at Wikimedia Commons

v t e Province of Bulacan
Malolos (capital) San Jose del Monte (largest city)
Municipalities	Angat Balagtas Bocaue Bulakan Bustos Calumpit Doña Remedios Trinidad Guiguinto Hagonoy Marilao Norzagaray Obando Pandi Paombong Plaridel Pulilan San Ildefonso San Miguel San Rafael Santa Maria
Component cities	Baliwag Malolos Meycauayan San Jose del Monte

v t e Province of Cavite
Trece Martires (de facto capital), Imus (de jure capital) Dasmariñas (largest city)
Municipalities	Alfonso Amadeo General Emilio Aguinaldo General Mariano Alvarez Indang Kawit Magallanes Maragondon Mendez Naic Noveleta Rosario Silang Tanza Ternate
Component cities	Bacoor Carmona Cavite City Dasmariñas General Trias Imus Tagaytay Trece Martires

v t e Province of Rizal
Antipolo (capital and largest city)
Municipalities	Angono Baras Binangonan Cainta Cardona Jalajala Morong Pililla Rodriguez San Mateo Tanay Taytay Teresa
Component City	Antipolo

v t e Geography of the Philippines
Geology	Benham Rise Benham Bank Manila Trench Marikina Valley fault system Philippine fault system Philippine Mobile Belt Philippine Sea plate
Landforms	Archipelagos Extreme points Headlands Hills Island groups islands Mountains ranges passes Ultras Peninsulas Plains Valleys Volcanoes active potentially active inactive
Water	Baselines Bays Gulfs Lakes Rivers Straits Waterfalls Wetlands
Seas	Bohol Camotes Celebes Philippine Samar Sibuyan Sulu South China Visayan
Administrative divisions	Regions Autonomous Provinces Cities Municipalities Barangays Purok Sitio
Environment	Climate Ecoregions Forests Landmarks National parks Protected areas Biosphere reserves World Heritage Sites Wildlife Fauna Flora

• Geography of Bulacan
• Geography of Metro Manila
• Geography of Rizal (province)
• Geography of Laguna (province)
• Geography of Cavite
• Geology of the Philippines
• Marikina
• Seismic faults of Southeast Asia