Philippine Fault Article: Tsutsumi, H. and Perez, J.S., Large-scale active fault map of the Philippine fault based on aerial photograph interpretation (2023)


The Philippine fault is a ~1250-km-long, left-lateral strike-slip fault extending NNW parallel to the Philippine archipelago. This fault has been very active in the past 200 years with several destructive earthquakes accompanied by surface rupture. However, there was no large-scale map of the Philippine fault, which is essential for mitigating seismic hazard from future earthquakes. We mapped the surface trace of the Philippine fault on 1:50000-scale topographic maps based mainly on interpretation of ~1:30000-scale aerial photographs. We then compiled these fault trace data on a Geographic Information System to produce the first digital active fault map of the Philippine fault. These 1:50000-scale active fault maps are available from the website of Philippine Institute of Volcanology and Seismology (PHIVOLCS). These maps reveal that there are notable along-strike variations in fault trace geometry and magnitudes of historical seismicity of the Philippine fault. The Philippine fault in central Luzon and Mindanao Islands are well segmented and produced large (M≥7) earthquakes. In contrast, the fault in Masbate and Leyte Islands are more continuous and produced only moderate earthquakes in the past 400 years. There are geomorphic and geodetic evidence of aseismic creeping on the Philippine fault in northern and central Leyte. These observations suggest that the Philippine fault may be comparable to the San Andreas fault in that both of the faults are composed of locked, transition and creeping segments as previously suggested.

Full paper:

Tsutsumi, H. and Perez, J.S., 2013. Large-scaleactive fault map of the Philippine fault based on aerial photograph and interpretation.Active Fault Research, 39, 29-37.


What type of fault is the Philippine fault? ›

The Philippine fault is a ~1250-km-long, left-lateral strike-slip fault extending NNW parallel to the Philippine archipelago. This fault has been very active in the past 200 years with several destructive earthquakes accompanied by surface rupture.

What are the active faults mentioned in the article are the faults active? ›

Active faults are structure along which we expect displacement to occur. By definition, since a shallow earthquake is a process that produces displacement across a fault, all shallow earthquakes occur on active faults. Inactive faults are structures that we can identify, but which do no have earthquakes.

Who has a map that shows the active faults in the Philippines? ›

Since 2003, Kyoto University and PHIVOLCS-DOST have been mapping the Philippine Fault. At present, approximately 90% of on-land-stretch of the PFZ has been mapped. This delineation is based on interpretation of available large-scale (at least 1:30,000) aerial photographs.

Can the Philippine Fault Zone cause tsunami? ›

The Philippines is vulnerable to tsunami due to the presence of offshore faults and trenches such as Manila Trench, Negros Trench, Sulu Trench, Cotabato Trench, Philippine Trench, and East Luzon Trough. Tsunamis in the Philippines are rare but could be devastating.

What causes Philippine Fault? ›

The Philippine Fault System is a major inter-related system of geological faults throughout the whole of the Philippine Archipelago, primarily caused by tectonic forces compressing the Philippines into what geophysicists call the Philippine Mobile Belt.

How do I know if my house is on a fault line? ›

The California Geological Survey has published an easy-to-use interactive map online — type in your address or share your location on your smartphone, and, voila, you'll know if you stand in a fault zone. Or, for that matter, a place at risk of liquefaction or a landslide unleashed by an earthquake.

What will happen if the Big One hits the Philippines? ›

Based on the study released in 2004, at least 34,000 persons will die while 114,000 will be injured, and 40 percent of residential buildings in Metro Manila will be affected—170,000 houses will collapse while another 340,000 will be partly damaged—and about 500 fire incidents will occur within the first hour of the ...

What is the safe distance from fault line? ›

PhiVolcs recommends avoiding construction within five meters on each side of a fault trace. This is equivalent to a total width of 10 meters.

What are the active and inactive faults in the Philippines? ›

Inactive faults are structures that we can identify but which do not have earthquakes. There are five major active faults in the Philippines: the Central Philippine Fault, Marikina Valley Fault, Western Philippine Fault, Eastern Philippine Fault, and Southern of Mindanao Fault.

What are the three 3 ways of determining an active fault? ›

Fault activity is assessed using geologic, geomorphic, geodetic, and seismologic data.

What is the big one fault line in the Philippines? ›

The “Big One” is a worst-case scenario of a 7.2-magnitude earthquake from the West Valley Fault, a 100-kilometer fault that runs through six cities in Metro Manila and nearby provinces.

What areas are affected by the Big One Philippines? ›

The West Valley Fault starts in Angat, goes down to Quezon City, Marikina, Pasig, Pateros, Muntinlupa, to as far as Carmona in Cavite. An earthquake of 7.5, the estimated magnitude for the time span mentioned, will not just affect these areas but any other places within a 100 km radius.

Which location of the Philippines is the reason why it is prone to earthquakes? ›

Eastern Mindanao, including Surigao del Norte, is one of the seismically active areas in the country because of the Philippine Fault and Philippine Trench, which are the main earthquake generators that can affect the area.

Why is it important to know the location of the active faults in the Philippines? ›

of PHIVOLCS said that the location of active faults is a major basis for people's preparedness for earthquakes, appropriate land use, contingency planning for disaster response, and design of houses, buildings and infrastructures.

What will happen during the Big One? ›

The 'Big One' is a hypothetical earthquake of magnitude ~8 or greater that is expected to happen along the SAF. Such a quake will produce devastation to human civilization within about 50-100 miles of the SAF quake zone, especially in urban areas like Palm Springs, Los Angeles and San Francisco.

How likely is it that Philippines could be hit by a tsunami? ›

Tsunami Hazard level: High ? In the area you have selected (Philippines) tsunami hazard is classified as high according to the information that is currently available. This means that there is more than a 40% chance of a potentially-damaging tsunami occurring in the next 50 years.

What is the main cause of fault? ›

A fault is formed in the Earth's crust as a brittle response to stress. Generally, the movement of the tectonic plates provides the stress, and rocks at the surface break in response to this.

What are the 10 active faults in the Philippines? ›

Map of known active faults in central and northern Luzon, the Philippines. CTF—Coastal Thrust Fault, PFZ—Philippine Fault Zone, VAF—Vigan-Aggao Fault, PF—Pugo Fault, TeF—Tebbo Fault, TF—Tuba Fault, DF—Digdig Fault, EZF—East Zambales Fault, and MVFS—Marikina Valley Fault System.

Why does the Philippines get so many earthquakes? ›

The Philippines lies along the Pacific Ring of Fire, which causes the country to have frequent seismic and volcanic activity. Many earthquakes of smaller magnitude occur very regularly due to the meeting of major tectonic plates in the region.

Should you buy a house on a fault line? ›

If your home is located on a fault line, you are typically at a higher risk than someone outside the zone. Although the chances of an earthquake remain very small, living on or near a fault line may be outside of your risk-acceptance level.

What are the dangers of living near a fault line? ›

The dangers people face include not only tremors but also other threats: Widespread smoke and ash can pollute the air and block out the sun for miles in every direction. Mudflows and landslides are potential threats as well.

Is it okay to build a house near the active fault? ›

Phivolcs now recommends avoiding construction within 5 meters on each side of a fault trace, or a total width of 10 meters. We may call this the ideal "10-meter wide no-build zone" in the vicinity of a fault. Ideally, we should not build in the 10-meter wide no-build zone to avoid the hazard of ground fissure.

What year will the Big One hit? ›

The chart tells us the average interval between large earthquakes is 138 years, plus or minus 30 years. Based on this average and standard deviation, the next large earthquake on the Hayward fault could be anywhere between 1977 and 2036, or even later, of course.

How overdue is the Big One earthquake? ›

California is located in a hot-zone of fault lines that can rupture without warning. Parts of the San Andreas fault have not ruptured in over 200 years, meaning it's overdue for a high-magnitude earthquake commonly referred to as "The Big One."

Did Philippines defeat us? ›

The Philippine President Emilio Aguinaldo was captured on March 23, 1901, and the war was officially declared ended by the American government on July 2, 1902, with a victory for the United States.

How far should you build a house or building from a fault line? ›

Buildings less than 10 kilometers from the Fault are vulnerable to Earthquake Damage according to the National Structural Code 2015.

What will you do if your house is located at the nearest fault line? ›

Before an Earthquake
  • Know your risk. Research the area and find out if you live near an active fault line. ...
  • Retrofit and reinforce your house. ...
  • Create a disaster plan. ...
  • Plan a week's worth of supplies for each person. ...
  • Stay away from hazards. ...
  • Take cover in a safe place. ...
  • Stay inside. ...
  • Be prepared for aftershocks.

What happens when you live on a fault line? ›

Strong shaking and fault rupture can also lead to many other problems, including landsliding, liquefaction, fires, disrupted transportation routes, broken water and gas pipes, downed electrical and phone lines, and many other dangerous conditions.

What are the 5 signs of active fault? ›

Active faulting is considered to be a geologic hazard and related to earthquakes as a cause. Effects of movement on an active fault include strong ground motion, surface faulting, tectonic deformation, landslides and rockfalls, liquefaction, tsunamis, and seiches.

Why do the Philippines have too many active faults? ›

The Philippines sits on a unique tectonic setting ideal to volcanism and earthquake activity. It is situated at the boundaries of two tectonic plates – the Philippine Sea Plate and the Eurasian plate – both of which subduct or dive beneath the archipelago along the deep trenches along its east and west seaboard.

Which province in the Philippines has no active fault? ›

Palawan: An Earthquake-free Area in the Philippines

The province of Palawan is the safest place in the Philippines from earthquakes. Palawan has no fault lines and will most likely not be affected once “The Big One” hits the country. There is no such thing as an earthquake-free zone.

What are the 3 main types of faults? ›

There are three main types of fault which can cause earthquakes: normal, reverse (thrust) and strike-slip.

What are the 3 main types of fault explain each of them? ›

Normal faults occur when two plates, one on top of the other, slide past each other and create the fault. Reverse faults occur when one plate slides under the other, creating a vertical offset. Strike-slip faults happen when two plates move horizontally past each other.

Can inactive faults be reactivated? ›

Inactive faults can become active again. In our case there are no signs of that, although UP seismologists remain observant. This diagram shows an earthquake along a fault. The focus of the earthquake is where the energy is released underground.

What is the estimated number of houses that will be destroyed if the Big One will happen? ›

According to the Metropolitan Manila Earthquake Impact Reduction Study (MMEIRS), a 7.2-magnitude earthquake from the West Valley Fault will result in the collapse of 170,000 residential houses and the death of 34,000 people. Another 114,000 individuals will be injured while 340,000 houses will be partly damaged.

Why the Philippines is very vulnerable to strong earthquakes like the Big One? ›

The Philippines is a country prone to natural disasters such as earthquakes [1]. It is surrounded by 5 active faults: Western Philippine Fault, the Eastern Philippine Fault, the South of Mindanao Fault, Central Philippine Fault, and the Marikina/Valley Fault.

What is the biggest earthquake fault line in the United States? ›

SAN FRANCISCO (KGO) -- While the San Andreas fault gets much of the attention after the devastating 1906 and 1989 quakes, it's the Hayward fault, which runs along the East Bay, that quake experts consider the most dangerous fault in America.

What are the top 3 places in the Philippines that are hazard prone to earthquake? ›

Ifugao, Lanao del Sur and Sarangani ranked high because of their high vulnerability to disasters while Rizal ranked the lowest.
The top ten provinces that are at risk to earthquake-induced shallow landslides are:
  • Ifugao.
  • Lanao Del Sur.
  • Sarangani.
  • Benguet.
  • Mountain Province.
  • Bukidnon.
  • Aurora.
  • Davao del Sur.

Which regions are high risk in term of earthquake in Philippines? ›

The proximity of Southern Mindanao to Celebes Sea, where undersea earthquakes frequently occur, makes this part of the country most vulnerable to tsunamis.

What area in the Philippines is at very high risk to typhoons? ›

The most frequently impacted areas of the Philippines by tropical cyclones are northern Luzon and eastern Visayas.

What are the five 5 common disasters in the Philippines? ›

Natural disasters
  • Typhoons. Around 20 typhoons hit the Philippines each year. Most typhoons occur from June to November. ...
  • Earthquakes. The Philippines is in an earthquake zone. ...
  • Volcanoes. There are numerous volcanoes in the Philippines, any of which can erupt without warning.

What are the 5 major earthquakes that hit the Philippines? ›

  • 1968 August 02 Casiguran Earthquake. ...
  • 1973 March 17 Ragay Gulf Earthquake. ...
  • 1983 August 17 Laoag Earthquake. ...
  • 1976 August 17 Moro Gulf Earthquake. ...
  • 1990 February 08 Bohol Earthquake.

What is the strongest earthquake in Philippines? ›

1. Moro Gulf Earthquake (1976) This Mindanao earthquake, which had a magnitude of 8.1 and killed a staggering number of people, is now regarded as the strongest and deadliest one in Philippine history. The epicentre of a tsunami, which reached a height of up to 9 metres, was located 40 kilometres from Sultan Kudarat.

How do you know where are active fault lines in an area in the Philippines? ›

The PHIVOLCS FaultFinder is an application capable to do proximity searches to active faults. It may be used to determine the location of active faults in an area and to measure the shortest distance between an active fault and a user's current location, which is determined by the gadget's tracking device.

What is the biggest fault in the Philippines? ›

The 1,200-km-long Philippine fault zone (PFZ) is a major tectonic feature that transects the whole Philippine archipelago from northwestern Luzon to southeastern Mindanao.

What type of fault is the Philippine Trench? ›

The Philippine Fault is a left-lateral strike-slip fault running almost parallel to the trench from Luzon to Mindanao, and the fault accommodates the trench-parallel component of left-lateral oblique convergence.

What kind of fault is Guinayangan fault? ›

Based on the latest available active faults map of the DOST-PHIVOLCS, the Guinayangan Fault is an active fault that traverses the central portion of Quezon Province. A fault is defined as active if it has shown movement within the past 10,000 years.

What are the 3 types of earthquake faults? ›

Different types of faults include: normal (extensional) faults; reverse or thrust (compressional) faults; and strike-slip (shearing) faults.

What are 4 types of faults? ›

There are four types of faulting -- normal, reverse, strike-slip, and oblique. A normal fault is one in which the rocks above the fault plane, or hanging wall, move down relative to the rocks below the fault plane, or footwall. A reverse fault is one in which the hanging wall moves up relative to the footwall.

What is the deepest hole in the Philippines? ›

Philippine Trench

The third deepest point in the world, the Galathea Depth in the Philippine trench, is 10.54 km below sea level.

How do I know if my house is in fault line? ›

To determine the distance of your current location to the nearest fault, turn on your gadget's tracking device. Click the “VFS Fault Nearest You” or “Active Fault Nearest You”. You may click on “Active Fault Based on Location” tab if you want to know the distance of a Barangay to the nearest active fault.

What fault line is Ilocos Norte on? ›

The Vigan-Aggao Fault has previously been described as an NNE- to NS-trending, east-dipping thrust fault (40° to 55° E), with a length of 132 km from Vigan (Ilocos Sur) to Bacsil (Ilocos Norte), based on aerial photograph interpretation and observed structures [40].

How deep is a shallow earthquake? ›

Shallow earthquakes are between 0 and 70 km deep; intermediate earthquakes, 70 - 300 km deep; and deep earthquakes, 300 - 700 km deep.

What is the most damaging type of earthquake? ›

The ground moves laterally, or shimmies side-to-side with no vertical component. Of the two types of surface waves, the L-waves are the most destructive. They can literally move the ground beneath a building faster than the building itself can respond, effectively shearing the base off of the rest of the building.

What are the 4 different types of earthquakes? ›

There are four different types of earthquakes: tectonic, volcanic, collapse and explosion. A tectonic earthquake is one that occurs when the earth's crust breaks due to geological forces on rocks and adjoining plates that cause physical and chemical changes.

What are the 5 kinds of faults? ›

What is a fault and what are the different types?
  • Normal Fault Animation.
  • Thrust Fault Animation.
  • Blind Thrust Fault Animation.
  • Strike-slip Fault Animation.

What are the 3 types of faults and their meaning? ›

Normal faults occur when two plates, one on top of the other, slide past each other and create the fault. Reverse faults occur when one plate slides under the other, creating a vertical offset. Strike-slip faults happen when two plates move horizontally past each other.

Which faults cause the most damage? ›

Reverse faults, particularly those along convergent plate boundaries are associated with the most powerful earthquakes, megathrust earthquakes, including almost all of those of magnitude 8 or more. Strike-slip faults, particularly continental transforms, can produce major earthquakes up to about magnitude 8.

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