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Fault Lines 101 for Homebuyers

At least one time in your life, You may have heard the line, “It’s not your fault.” Don’t worry, we won’t be discussing anything cheeky here. We will, however, be talking about “faults” in relation to real estate. And those faults aren’t ours or yours. 

In this article we will be fully discussing what fault lines are, where they are located in the Philippines, and a bunch of other things that you as a homebuyer should know before deciding the location of your next home. 

What Are the Major Fault Lines in the Philippines?

Before we discuss anything else, we think it’s really important for you to know what fault lines are. SPOILER ALERT: They’re not your fault.  

Kidding aside, fault lines are defined as cracks in the Earth’s crust. You can still remember your science lessons when you were younger, right? Apparently, the rocks on the Earth’s crust, on both or either side of the crack, can slide past each other. The crack will be under enormous pressure because of the two pieces of the Earth’s crust that are pushing each other. When it gives, an earthquake results. 

Currently, there are five major fault lines in the Philippines: 

  1. Western Philippine Fault – this covers the areas of the Luzon Sea, Mindoro Strait, Panay Gulf, and Sulu Sea 
  2. Eastern Philippine Fault – this covers the area of the Philippine Sea 
  3. South of Mindanao Fault – this fault affects the areas of the Moro Gulf and Celebes Sea 
  4. Central Philippine Fault – this covers 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 
  5. Marikina Valley Fault System – this covers the areas of Montalban, San Mateo, Marikina, Pasig, Taguig, Muntinlupa, San Pedro, Biñan, Carmona, Santa Rosa, Calamba, Tagaytay, and Oriental Mindoro
fault lines
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Things To Keep in Mind When Planning To Buy a Home Near a Fault Line 

Check for earthquake resistance 

Your first step is to determine whether a building has earthquake-resistant features. It’s important that structures stay up to date with the latest earthquake-proof technology designed to mitigate hazards. 

Some of the features to check for include specialized diaphragms, cross-bracing, moment-resisting frames, shear walls, trusses, and lightweight roofing. If you have no knowledge of these features, hire an expert to check them out. 

fault lines inspection

Conduct a structural inspection

If the home you are considering is a few years old, it may have been through small earthquakes already. Have the home inspected by an expert to ascertain the quality of its build and any hidden structural issues. 

Damage from earthquakes is not always apparent to the untrained eye, and a house that looks fine to you on the surface could be hiding heavy damage. 

Prioritize earthquake-proof retrofitting 

Making a building earthquake-proof is a substantial investment on your part. There are myriad structural additions that can help your home endure a massive earthquake. Older homes, in particular, may need the latest earthquake retrofits and upgrades. 

Before buying a home, determine the types of accommodation needed to enhance a home’s earthquake-readiness and price them during the escrow period. 

fault lines retrofitting

Get earthquake/calamity insurance 

A standard homeowner’s insurance doesn’t cover earthquakes. Buying a home in earthquake-prone locations may force you to get a special coverage that protects your home and possessions from “acts of God” incidents such as earthquakes or typhoons. You should get quotes for at least earthquake insurance before you buy your home. 

Earthquakes and Fault Lines 

We’ve established earlier that earthquakes occur along fault lines, cracks in the Earth’s crust where tectonic plates meet. They occur where plates are subducting (one plate slipping below the edge of another), spreading, or colliding. 

As the plates grind together, they get stuck and pressure builds up. Finally, the pressure between the plates is so great that they break loose

When an earthquake occurs on one of these fault lines, the rock on one side of the fault slips into the other. 

Do take note that anyone can experience earthquakes even if they are relatively far away from a fault line. But don’t worry, with proper research on your property and the farther you are from it, the risks of damage to your properties are greatly reduced. 

How Far Away From a Fault Line Is a House Considered Safe?

The Philippine Institute of Volcanology and Seismology (PHIVOLCS) recommends avoiding constructing anything within 5 meters on each side of a fault line. We call this guide the “10-meter wide no-build zone.” 

Ideally, you should not build within this area to avoid earthquake hazards like the ground breaking up. If circumstances allow, we recommend building your new home much farther away. 

What If Your House Is on A Fault Line? 

It means you’re in an area with great risk of the ground breaking up during an earthquake. This doesn’t necessarily happen to all areas, but the chance the ground breaks up is higher compared to those places that are relatively far away. This will also depend on where the earthquake is, and which faults were involved in the quake. 

What Is the Most Active Fault Line? 

The Marikina Valley Fault Line is considered to be the most geologically active fault line among the five we have mentioned earlier, according to PHIVOLCS. The Valley Fault System is divided into western and eastern parts. The areas affected by this fault line are densely populated and home to a lot of infrastructures. 

Additionally, PHIVOLCS reported that the fault line is expected to move soon. If this movement happens, it is estimated that the quake can reach a magnitude of 7.2. Casualties are predicted to be as high as 35,000, cause injury to 120,000, and render more than 3 million people homeless. 

Experts have also warned that a movement of this fault line may actually cause the Taal Volcano to erupt. The fault line was also renamed the West Valley Fault Line. 

We’re sure you want none of that, so if you’re looking for a home in Metro Manila, then Quezon City, Pasay City, and the City of Manila are some areas that are considered safe from earthquakes because of their lack of small or hidden fault lines. 

Final Thoughts 

Now that you’ve learned about fault lines, it’s time to sketch up your plans when it comes to home buying. This is important to keep your house and your family safe from the damaging effects of earthquakes. These natural phenomena cannot be predicted after all, so your best bet is precaution. 

Make sure to bookmark this article so you can go back to it should you find a home that’s somewhere near a fault line. If you liked this article and want more guides just like this on everything real estate, head to our resource page

If you’re looking for houses to buy, there are a lot of great listings on Enta to get you started on your hunt. Remember, safety comes first before style and profitability. Good luck!