MAP: Where Are the Major Fault Lines in the Philippines?

Earthquakes always happen somewhere, but this doesn’t mean you should be unconcerned when discussing such occurrences. Experts revealed that magnitude 2 and smaller earthquakes happen over a hundred times daily. But what about higher-intensity earthquakes?

In the Philippines, the most destructive quake happened in 1968. An intensity eight earthquake jolted the town of Casiguran, Aurora and also left severe impacts on Metro Manila, where major buildings sustained varying levels of damage. It was also estimated that the overall property damage cost several million dollars.

Hence, one cannot dismiss the danger of living near earthquake fault lines. Such lines are located in places where two tectonic plates meet and where earthquakes could wreak much havoc.

To determine if your current or future property stands in an earthquake-prone area, check out the fault line map below:

Philippine Fault Zone

Map Where Are the Major Fault Lines in the Philippines? Lamudi
Source: Lamudi.com.ph

One explanation for why we experience several destructive quakes is the existence of the Philippine Fault Zone (PFZ), a 1,200-kilometer (km) tectonic feature that runs across the country. The fault zone starts from northwestern Luzon and ends in southeastern Mindanao, traversing the following areas:

  • Ilocos Region
  • Nueva Ecija
  • Quezon Province
  • Masbate
  • Leyte
  • CARAGA Region
  • Davao Gulf 
  • Davao Oriental

The PFZ has been the source of massive earthquakes in recent years, including the magnitude 7.7 Luzon quake (1990) and magnitude 6.2 Masbate earthquake (2003). 

Most Notable Faults in the Philippines 

Frequent ground shaking happens in the country because of its position along the Pacific Ring of Fire, which makes it vulnerable to quakes and volcanic eruptions. Beyond this, the Philippines is also home to inter-related geological faults that include the following:

Guinayangan Fault 

According to the 2020 data from the Philippine Institute of Volcanology and Seismology (PHIVOLCS), the Guinayangan Fault is an active fault traversing Quezon Province’s central portion, and is also a part of the PFZ. 

The Guinayangan Fault can generate high-intensity quakes and was the cause of the magnitude 7 Ragay Gulf Earthquake. During this event, intensity eight ground shaking was recorded in the areas of Guinayangan, Calauag, and Lopez in Quezon. 

Important to note: Magnitude and intensity measure different characteristics of an earthquake. The former measures the energy released at the earthquake’s source. The latter tells the strength of the ground shaking, determined by the quake’s effects on people and structures. 

Masbate Fault

Masbate is considered a seismically active region in the country, which explains the frequent quakes in the area. Like the Guinayangan Fault, Masbate Fault is also a segment of the PFZ. There are also other potentially active faults in Masbate, including the Uson Fault and Southern Masbate Fault.

The magnitude 6.6 earthquake that struck the province in August 2022 was caused by the movement of the PFZ. Nearby provinces that felt an impact include Aklan, Albay, Biliran, Capiz, Leyte, and Negros Occidental.

Vigan-Aggao Fault

Located in the westernmost part of PFZ, in northern Luzon, is the 140-km Vigan-Aggao Fault. A study published in 2020 showed that the fault has four segments: Santa-Sinait, San Juan-Vintar, Bacarra-Burgos, and Pagudpud. 

Besides the Vigan-Aggao Fault, Ilocos Region could also be severely affected by the West Valley Fault, should the “Big One” or the worst-case scenario of an earthquake happen. 

Marikina Valley Fault System

Marikina Valley Fault System
Source: Lamudi.com.ph

Finally, we have the Marikina Valley Fault System, one of the most well-known and feared fault lines in the Philippines. It runs from Doña Remedios Trinidad in Bulacan and ends in Canlubang in Laguna. The active fault system also traverses six cities in Metro Manila and the nearby provinces of Rizal and Laguna. 

There are several recognized faults within the Marikina Valley Fault System, but the most well-known are these two segments: 

East Valley Fault

The East Valley Fault is around 10 km long and traverses the areas of Rodriguez and San Mateo in Rizal Province. The fault reportedly moves roughly every 400 years and could generate a magnitude 7.2 quake and a casualty of over 30,000 people. 

West Valley Fault 

Meanwhile, the West Valley Fault is 100 kms in length and runs through the portions of Quezon City, Pasig, Marikina, Makati, Taguig, and Muntinlupa in Metro Manila and nearby provinces. The fault could trigger the “Big One” and be followed by a tsunami, according to PHIVOLCS.

Knowing these major and active faults in the Philippines, it becomes clear why earthquakes frequent different parts of the country. If you live in a high-risk area, go beyond doing the duck, cover, and hold. Retrofit your house, create a disaster plan, and put together an emergency kit. 

For those who plan to acquire real estate in the Philippines, go for a quake-proof property or choose a location away from the hazardous areas on our fault line map.

Stay tuned for the latest real estate news and tips by following Lamudi on FacebookTwitterInstagramYoutube, and LinkedIn.

Sources: PHIVOLCS, eFOI, MDPI Open Access Journals, PNA

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