The West Valley Fault
A 100 kilometre active fault under Greater Metro Manila. PHIVOLCS says it can produce a magnitude 7.2 earthquake, and you can check how far you live from it in a few minutes.
No instruction on this page is specific to this fault. What to do when it moves is what to do in any strong earthquake, and that is set out step by step in the earthquake guide: what to do before, during and after. This page covers the part people search the fault's name for: where it runs, what PHIVOLCS expects, and how to find out whether it runs near you.
What it is
The West Valley Fault is one of the two segments of the Valley Fault System, which DOST describes as an active fault system. The other segment is the East Valley Fault, about 10 kilometres long, in Rizal. The West Valley Fault is the long one: about 100 kilometres, running through cities and towns in five provinces.
- Bulacan
- Rizal
- Metro Manila
- Cavite
- Laguna
DOST says the West Valley Fault can generate a large earthquake of magnitude 7.2, and that this is the earthquake commonly called "The Big One". PHIVOLCS mapped both segments in detail in the Valley Fault System Atlas, a printed handbook of large scale maps of the areas the faults cross, released in 2016 and made available online.
Source: DOST, Prepare for "The Big One": DOST makes Valley Fault Atlas available online (3 February 2016). Read 1 October 2026.
What PHIVOLCS expects if it moves
PHIVOLCS has modelled a magnitude 7.2 earthquake on the West Valley Fault as a scenario for planning. In it, Metro Manila feels Intensity VIII shaking, which on the PHIVOLCS scale is very destructive. In the agency's own Filipino:
"Mahigit 30,000 katao ang maaring mamatay at 14,000 katao ang maaring lubhang masasaktan."
More than 30,000 people could die and 14,000 could be seriously injured.
PHIVOLCS is clear that this is a scenario and not a prediction. It is a picture of the worst case, drawn so that local governments and communities plan for it. Nobody can say when the fault will move. What the difference between magnitude 7.2 and Intensity VIII means is explained on its own page.
Source: PHIVOLCS, Earthquake Scenarios: Mahalaga sa Tamang Paghahanda at Pagtugon sa Malalakas na Lindol. Read 1 October 2026.
How to check how close you are
The question most people bring to this fault is whether their barangay is on it. PHIVOLCS answers that for any address with the FaultFinder, a free web tool that measures the distance from a point to the nearest mapped active fault.
- Step 1
Open the FaultFinder and turn on location
PHIVOLCS asks you to turn on your gadget’s tracking device so the tool can measure from where you are standing.
- Step 2
Choose the Valley Fault System
For anywhere in the Greater Metro Manila Area, select "Valley Fault System (VFS)". Elsewhere, choose "Other Fault Systems".
- Step 3
Ask for the nearest fault
Click "VFS Fault Nearest You". To check a barangay rather than your own location, use the "Active Fault Based on Location" tab, or double click any place on the map.
- Step 4
Read the result
It gives the distance to the nearest fault, the fault and segment name, the year it was mapped and the map scale used.
Source: PHIVOLCS, The PHIVOLCS FaultFinder. Read 1 October 2026.
DOST gives the reason the maps exist: knowing where active faults are is what lets a city plan its land use so that ground the faults cross is avoided as a site for houses and other structures. If the FaultFinder shows a fault close to your home, that is the question to put to your city or municipal planning office and your barangay. This site does not give a safe distance, because neither of the PHIVOLCS and DOST pages read for it does.
What to do about it
Living near the fault does not change the instruction for the shaking itself. It makes the preparation more urgent. PHIVOLCS's household advice for any strong earthquake covers it:
- Duck, cover and hold : the three words for the shaking, and the four places where they do not apply.
- An evacuation plan for your home or school : the open space to go to, and who counts heads when you get there.
- The earthquake drill, phase by phase : the six phases PHIVOLCS sets out for schools.
- The go bag checklist : UNICEF Philippines' list, packed once and kept by the door.
Read the earthquake guide Tsunami: the signs and the warnings