Why the Philippines Remains Highly Prone to Earthquakes in 2025
The Philippines continues to experience
significant seismic activity in 2025, with recent events underscoring the
nation’s geological vulnerability. A magnitude 6.9 earthquake struck Cebu on
September 30, resulting in at least 72 fatalities (Time, 2025), and twin
earthquakes including a magnitude 7.4 event on October 10 caused additional
casualties and widespread damage (Reuters, 2025). These events highlight the
ongoing earthquake risk faced by more than 109 million Filipinos across the
archipelago.
The country’s seismic proneness arises
from its location within the Pacific Ring of Fire and its complex tectonic
setting involving multiple active fault systems and subduction zones. Subduction of the Philippine Sea Plate beneath the
Philippine Mobile Belt occurs along the Philippine Trench and East Luzon Trench
at rates up to 8.2 cm/year, while westward subduction of the Sunda Plate along
the Manila and Negros trenches proceeds at up to 5 cm/year. Oblique convergence
is accommodated by the left-lateral Philippine Fault System and intra-belt
strike-slip faults such as the Marikina Valley Fault, which threaten densely
populated areas including Metro Manila (Temblor, 2021).
The Philippines contains 185 active
fault segments grouped into 30 systems, producing frequent shallow crustal
earthquakes. The West Valley Fault, a segment of the Marikina Valley Fault
System, poses the greatest risk to Metro Manila. A magnitude 7.2 event on this
fault could cause up to 50,000 fatalities and extensive infrastructure damage
(PSA Intelligence, 2024). The recent Cebu earthquake ruptured the previously
unmapped Bogo Bay Fault, illustrating the challenge of fully mapping offshore
faults (Sun Star, 2025).
Six major subduction zones also surround
the archipelago, each capable of generating large megathrust earthquakes and
tsunamis. The Philippine Trench can produce earthquakes up to magnitude 8.5,
while the Manila Trench poses significant tsunami hazards to western coastlines
due to its long recurrence interval and accumulated strain (NHESS, 2024).
Despite these risks, seismic monitoring
remains limited. The Philippine Institute of Volcanology and Seismology
(PHIVOLCS) operates 125 seismic stations, fewer than half the number needed for
comprehensive coverage. At current funding levels, PHIVOLCS can install only
four stations per year, requiring decades to fill monitoring gaps (Sun Star,
2025). This deficiency hinders precise earthquake localization and early warning
system development.
Urban vulnerability is pronounced in
Metro Manila, where population growth from 10.9 million in 2004 to 13.5 million
in 2020 has outpaced updates to seismic risk assessments. The Metro Manila
Earthquake Impact Reduction Study (MMEIRS) estimates up to 50,000 fatalities,
114,000 injuries, and damage to 170,000 residences in a West Valley Fault
magnitude 7.2 scenario, with additional deaths from post-quake fires (Inquirer
Opinion, 2025; PSA Intelligence, 2024).
In response, the Philippine government
enacted the PHIVOLCS Modernization Act (Republic Act No. 12180) in April 2025,
providing ₱1.25 billion annually for four years and ₱2 billion in the fifth
year to upgrade seismic and volcanic monitoring, develop forecasting
capabilities, and enhance data processing centers (Sun Star, 2025). The Metro
Manila Priority Bridges Seismic Improvement Project, funded by JICA, allocates
₱10.34 billion to retrofit key bridges, including the Guadalupe and Lambingan
bridges (PTNI, 2025).
Tsunami risks compound earthquake
hazards. Offshore subduction earthquakes can generate waves exceeding 5 m along
eastern coasts for rare magnitude 9.0 events, while magnitude 7.4 events off
Mindanao in October 2025 prompted tsunami warnings within 300 km of the epicenter
(EJAET, 2025; Reuters, 2025).
The Philippines’ seismic susceptibility
is a consequence of persistent tectonic forces that will continue irrespective
of human actions. Effective risk reduction demands sustained investment in
monitoring, infrastructure resilience, public education, and preparedness to
mitigate the inevitable impacts of future seismic events.
References
Inquirer
Opinion. (2025, July 23). Earthquake preparedness. Philippine Daily
Inquirer. https://opinion.inquirer.net/184875/earthquake-preparedness
NHESS. (2024,
July 8). Tsunami hazard assessment in the South China Sea based on geodetic
locking of the Manila subduction zone. Natural Hazards and Earth System
Sciences, 24, 2303–2336. https://doi.org/10.5194/nhess-24-2303-2024
PSA
Intelligence. (2024, December 15). Business preparedness amid earthquake risk
in Metro Manila. PSA Intelligence. https://psaintelligence.com/special-report/business-preparedness-amid-earthquake-risk-in-metro-manila/
PTNI. (2025,
February 18). Strengthening resilience: Strategies for disaster risk reduction
under the Marcos administration. Philippine Trade and Investment News. https://ptni.gov.ph/strengthening-resilience-strategies-for-disaster-risk-reduction-under-the-marcos-administration/
Reuters. (2025,
October 9). At least 7 dead after Philippines hit by twin quakes, tsunami
warning issued. Reuters. https://www.reuters.com/business/environment/magnitude-72-earthquake-strikes-philippines-mindanao-emsc-says-2025-10-10/
Sun Star. (2025,
October 10). Phivolcs needs more stations to monitor fault-riddled PH. Sun
Star Cebu. https://www.sunstar.com.ph/cebu/phivolcs-needs-more-stations-to-monitor-fault-riddled-ph
Temblor. (2021,
July 31). Latest Philippine earthquake reveals tectonic complexity. Temblor. https://temblor.net/earthquake-insights/latest-philippine-earthquake-reveals-tectonic-complexity-13026/
Time. (2025,
October 2). Why the Philippines’ earthquake was so deadly. Time. https://time.com/7322543/philippines-earthquake-cebu-why-so-deadly-night-manila-big-one/
