A study conducted by the Philippine Institute of Volcanology and Seismology (Phivolcs) projects that a magnitude-7.2 earthquake along the West Valley Fault could cause widespread destruction, including the collapse of at least 168,000 buildings and the deaths of over 33,000 people across Metro Manila and surrounding provinces.

The study highlighted the fault’s significant threat to public safety, with a focus on high-density urban areas that are most vulnerable to a major earthquake.

The West Valley Fault is an approximately 100-kilometer-long active fault line that traverses several provinces and cities, including Bulacan, Rizal, Laguna and Cavite, as well as highly populated areas like Quezon City, Pasig City, Marikina City, Taguig City and Muntinlupa City.

Phivolcs continuously monitors the fault for seismic activity, given the high risk it poses to the urban centers.

In an interview with DAILY TRIBUNE, Phivolcs Senior Science Research Specialist Bhenz Rodriguez discussed the agency’s ongoing surveillance efforts. He noted that the most recent earthquake near the West Valley Fault was a magnitude-1.5 tremor recorded last 14 March in Doña Remedios Trinidad in Bulacan.

Rodriguez said the earthquake occurred near the fault but was not generated by it. Despite it being a minor quake, he said it serves as a reminder of the active fault’s danger.

The last major earthquake recorded in the West Valley Fault occurred in 1658, and experts believe the fault generates significant earthquakes every 200 to 400 years.

‘The Philippines lies within the Pacific Ring of Fire, so earthquakes are inevitable. We experience them regularly.’

With modern cities now situated along its path, the possibility of a catastrophic quake is a major concern.

Rodriguez also addressed the recent magnitude-7.7 earthquake in Myanmar and the magnitude-7.1 quake in Tonga, stressing that these events were not directly related to the Philippines.

“The Philippines lies within the Pacific Ring of Fire, so earthquakes are inevitable. We experience them regularly,” he said.

The frequency of seismic activity in the region makes preparedness and infrastructure resilience even more critical.

A magnitude-7.2 earthquake along the West Valley Fault could lead to an Intensity-8 ground shaking, which would make it nearly impossible for people to remain standing, while buildings and debris could collapse.

Rodriguez warned of other earthquake-related hazards such as liquefaction, where the ground behaves like a liquid, ground ruptures, landslides and tsunamis, particularly in areas near bodies of water.

In light of these risks, Office of the Civil Defense Undersecretary Ariel Nepomuceno stressed the urgent need for strong, resilient infrastructure.

“We need to catch up on engineering solutions,” he said. “Buildings, infrastructure and bridges should be designed to withstand the force of a strong earthquake.”

His comments underscore the importance of modern engineering standards that can withstand such seismic events, especially in high-risk areas like Metro Manila.

In addition to structural integrity, Rodriguez discussed the importance of preparedness.

The government has conducted earthquake drills and developed evacuation plans, but he noted that the question remains whether the country is truly ready for a major earthquake.

“It’s a tough question,” Rodriguez admitted. “We should be prepared, especially in Metro Manila. If the West Valley Fault moves, we need to be ready with clear and coordinated responses. That’s why we conduct these drills — to visualize and rehearse what our best response would be in the event of a major earthquake.”

Despite the government’s efforts, Rodriguez said the full impact of such a devastating event would depend on multiple factors, including the fault’s exact movement, the magnitude of the earthquake, and the level of preparedness of both individuals and local authorities.

As such, continued education, infrastructure improvements, and the readiness of local government units will be critical in minimizing the damage from a potential earthquake along the West Valley Fault.

Palace urges LGUs to prepare

Meanwhile, Malacañang has urged local government units to intensify the inspection of buildings in their areas as the threat of “The Big One” persists.

“To the local government units, we urge that their building officers conduct inspections regularly and be strict in granting permits for the construction of buildings that may not be structurally sound,” Palace Press Officer Undersecretary Claire Castro said in a briefing on Monday.

The reminder comes after Myanmar was hit by a 7.7-magnitude earthquake on Friday.

Castro acknowledged that it’s difficult to say whether any country is truly “ready” for such a disaster, but emphasized the importance of being prepared.

“Almost all of our government agencies are prepared for this — we’re conducting earthquake drills, fire drills and have ‘go bags’ ready,” she said.

She also called on the public to cooperate in information dissemination and to help the country prepare for any disaster scenario.

Office of Civil Defense Administrator Ariel Nepomuceno noted that the Philippines is not fully ready for such catastrophic events. He pointed out that current preparations only include basic actions like “duck, cover and hold,” and inspections of structures and houses nationwide.

Nepomuceno emphasized the need to focus more on engineering solutions, ensuring that buildings, houses and infrastructure are constructed strong enough to withstand major earthquakes.