Active Philippine Fault Lines and the Areas Affected


A profound space hailing in the Pacific Ocean lies the Ring of Fire which houses the most number of earthquakes and volcanic eruptions to occur in the planet. The Ring of Fire is respective towards a series of oceanic trenches, volcanic arcs, volcanic belts, and plate movements.

One of the countries the Ring of Fire has a massive association with is the Philippines, and due largely to the country’s specific location in Southeast Asia, the country is bound to experience multiples of sudden volcanic eruptions and earthquakes.

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Read: Active Philippine Fault Lines: How do You Know if Your Area is Near a Fault Line?

Why the Philippines?

Three (3) of the tectonic plates that surround the Philippines are the Philippine Plate in the East; the Eurasian Plate in the West; and the Indo-Australian Plate in the South. Hence, the occurrence of several fault lines is the resulting action of the movements of these tectonic plates.

The five active Philippine fault lines consist of:

  • Western Philippine Fault which affects the areas of Luzon Sea, Mindoro Strait, Panay Gulf, and Sulu Sea;
  • The Eastern Philippine Fault which affects the area of Philippine Sea;
  • South of Mindanao Fault which affects the areas of Moro Gulf and Celebes Sea;
  • The Central Philippine Fault which affects the areas of Aurora, Quezon, Masbate, Eastern and Southern Leyte, Agusan del Sur, Agusan del Norte, Davao del Norte, and the entire area of Ilocos Norte; and
  • The Marikina/Valley Fault System which affects the areas of Montalban, San Mateo, Marikina, Pasig, Taguig, Muntinlupa, San Pedro, Binan, Carmona, Santa Rosa, Calamba, Tagaytay, and Oriental Mindoro

Read: How to Use The HazardHunter PH Program?

The most active of all Philippine fault lines

Amongst all the active Philippine fault lines, Marikina Valley Fault Line is the most geologically active one in the country according to Philippine Institute of Volcanology and Seismology (PHIVOLCS).

It has been noted that a subsequent result of this fault line moving may cause the Taal Volcano to erupt. And due to the panic that arose because of its name, the fault line has been renamed to West Valley Fault Line during PHIVOLCS director Raymundo Punongbayan’s term.

Read: How Cities and Municipalities Should Prepare for an Earthquake

The Central Philippine Fault Zone, on the other end of the specturm, is the source of fault creep activity, slow slip event, and great earthquakes in the archipelago.

Blind faults also exist throughout the country; these blind faults are active faults which have not manifested through the ground surface and, though they may have moved in the past, the magnitudes these faults cultivated were insufficient to break into the ground surface which led to the development of the current project PHIVOLCS is working on, “Mapping of Earthquake-Related Landforms in the Philippines.”

Now, we have too few resources that can aid agencies to determine the risk and the danger of a fault line in conjunction with how it can have drastic effects on the Filipino community.

How can we manage and maintain active Philippine fault lines?

This project aims to update the 1:50,000 scale Active Faults maps for all provinces of the Philippines, according to the current PHIVOLCS director, Renato Solidum. It also utilizes high-resolution satellite images to interpret landforms that show evidence of active faulting.

Read: Tired Of All Those Generic Earthquake Tips? This Is The Ultimate Earthquake Survival Guide That Would Literally Save Lives

Global Positioning System or GPS is one of the newest technologies PHIVOLCS uses to observe active Philippine fault lines; this technology helps geologists identify which among the faults is creeping/sliding and not moving.

Solidum said that should a fault be deemed as active but is locked, it doesn’t entirely mean that we’re safe; it could be far worse than that.

If the fault is active but is locked, it means that it is storing up energy which would be released in future earthquake events. However if the fault is creeping or sliding, it means that the probability of a strong earthquake to happen is quite small as the fault is constantly releasing energy.”

The agency has also constructed its own Unmanned Aerial Vehicles or UAVs to ensure low maintenance cost and sustainability of the equipment. These drones are used to help both in the mapping of active faults, especially in areas that are not easily accessible, and in the assessment of damage after an earthquake or volcanic eruption. Geophysical instruments, on the other hand, are used to map active Philippine fault lines that encompass through the sea.

Read: List of Barangays in Metro Manila, Nearby Provinces Near Earthquake Fault

The PH government’s action

The country’s history is found to be dotted with destructive and frequent earthquakes through the years as caused by these active fault lines. Despite the vicinity within the epicenter or not, buildings and countless of lives cannot escape the destruction that follows during and after the occurrence of earthquakes.

However, the Philippines has done minimal effort to update the country’s building code which would have afforded a better chance of the buildings situated upon the Philippine soil to withstand against greater calamities. Solidum notes that local governments should be more strict in building inspection and in the issuance of permits for building design and construction as, according to him, the country has a good building code which is not always followed.

Read: How to avail Home Development Fund (Pag-IBIG)–Calamity Loan

Scientists also have stated that there is no such way to predict incoming bouts of earthquakes. These quakes are the resulting behavior of the stresses earth has accumulated over time as said by University of the Philippines National Institute of Geological Sciences Director Mario Aurelio.

Consequentially, earthquakes that occur near the surface and under the sea may generate tsunamis. Aftershocks may also ensue after the largest shock of an earthquake series. The magnitude of the shocks were generally of a lesser extent as opposed to the main one and may continue for days, weeks, and even years.

Strategies in finding out and determining volcanic activities

PHIVOLCS regularly conducts walk-the-fault activities in which state geologists assist local government units in identifying the location of the active faults that pass through their communities.

Read: How to apply for Social Security System (SSS) Calamity Loan – Requirements and Procedure

The agency also created FaultFinder, a web-based application, to make the active fault maps easily accessible to everyone; this application helps identify the distance of the user’s location to the nearest active Philippine fault lines. You can access the FaultFinder application here.

Read more about that here: PHIVOLCS Will Introduce 4 Disaster Reduction Apps

For now, all we can do is to count on the devices, technologies, and the efforts being made by multiple private and government agencies in determining the activity of the active Philippine fault lines.

Due to the recent eruption of the Taal Volcano in the province of Batangas, millions of people from all around the globe were alarmed. And the outburst of all these craziness was due to the fact that our country had less technologies that could have possibly detected; or even predicted the eruption of the volcano.

Now that you’re aware of the different active Philippine fault lines, be sure that you know what to do should you be residing in any of the near locations of them.

Source: Prezi | The Philippine Daily Inquirer

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