CEBU, Philippines -- Over a hundred sinkholes have been dioscovered across the northern Cebu town of San Remigio, Mayor Mariano Martinez said.
He warned that more may still be hidden underground following the powerful 6.9-magnitude earthquake that struck the region earlier this week.
In an interview with CDN Digital on Saturday, October 4, Martinez said the Philippine Institute of Volcanology and Seismology (Phivolcs) had already briefed the local government weeks before the quake about the presence of numerous San Remigio sinkholes.
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"Actually few weeks ago niari ang Phivolcs, ni briefing sila namo, and according to their assessment, that we have over a hundred sinkholes diri sa among lungsod. I don't know why, I was even surprised nga kadaghan ba," Martinez said.
"But karon, after the earthquake, we discovered them. Daghan ni pop up sa among lungsod. I'm positive naa pay daghan nga wala pa makit-e," he added.
Martinez said at least 15 sinkholes of varying sizes have so far been confirmed in Sitio Sansan, Barangay Maño -- but these are only part of a larger and still unfolding picture. Some sinkholes have also appeared near Poblacion, which suggests they are scattered across different parts of San Remigio.
The mayor said most of these sinkholes became visible after the series of tremors that rocked northern Cebu following the September 30 earthquake, whose epicenter was traced near Bogo City.
He added that many residents living near identified sinkholes have already started evacuating out of fear.
"For now, we are informing the people about the sinkholes, and some people close to a sinkhole are evacuating," he said. "Ang uban murag safe pa, pero dapat dili gyud magpabilin duol. Ang mga duol gyud kato sila ang nag-evacuate kay nakuyawan man."
Currently, a little over a thousand residents have evacuated to open fields, as many are reluctant to stay in covered courts or buildings due to ongoing aftershocks.
"Before naa man gyud mi evacuation centers like covered courts, pero karon nobody wants to go into buildings kay kuyawan man... There are people in tents in our open field. And there are plans to come up with a tent city with the help of the national government," Martinez said.
The Department of Public Works and Highways (DPWH) is expected to inspect potential sites for the proposed "tent city," similar to temporary settlements built by humanitarian agencies like the Red Cross after Typhoon Yolanda.
Sinkholes linked to fault movement
Martinez admitted that while the local government is aware of the presence of the San Remigio sinkholes, more technical assessments are needed from national agencies to determine their full impact and the necessary safety measures.
"Apparently, sinkholes mahitabo na tungod sa shifting of faults. I don't really know sa pagka karon the effects -- whether people need to evacuate if you are living near a sinkhole and what to do after," he said."Most probably, these can become no-build zones. I have to find out with Phivolcs gyud kay para nako I am still being educated pa about this."
The Mines and Geosciences Bureau (MGB) in Central Visayas confirmed that San Remigio, along with other quake-affected towns like Bogo, Tabogon, Daanbantayan, and Medellin, has been issued a Subsidence Threat Advisory following the confirmed emergence of sinkholes and ground subsidence after the earthquake.
In its advisory, MGB-7 warned that sinkholes, particularly those caused by cover collapse, pose serious risks to life, property, and infrastructure, and stressed that affected areas must be declared high subsidence hazard zones.
The agency recommended immediate precautions such as:
* Restricting access to sinkhole-affected and crack-prone areas
* Installing caution tapes and warning signs
* Avoiding backfilling without proper assessment
* Monitoring further ground movement, especially after heavy rainfall
* Discouraging construction or development in affected zones
The MGB also said sinkhole development could worsen over time due to heavy rainfall, dropping water tables, or seismic activity.
What are sinkholes?
A sinkhole is a natural depression or hole that forms in the ground when the surface layer collapses into an underground cavity. These usually develop in areas with limestone, carbonate rock, or other soluble materials, which gradually dissolve due to water movement, creating voids beneath the surface.
Sinkholes can suddenly appear after earthquakes, heavy rainfall, or groundwater withdrawal, posing threats to homes, roads, and structures. Some are small and harmless, while others can expand rapidly, swallowing large areas and endangering lives.
San Remigio's call
With ongoing aftershocks and new sinkholes appearing, Martinez urged national agencies to expedite their technical assessments and assist the town in developing safety guidelines.
"Right now, what we are really scared of is the earthquake. We are in a fault line man gud, and aftershocks are still being felt," he said. "We need to be totally informed about what to do."
San Remigio, one of the hardest-hit towns in northern Cebu, continues to experience tremors days after the 6.9-magnitude quake. Local officials are urging residents to remain vigilant, report any new sinkholes, and avoid high-risk areas until experts have completed their evaluations.
The municipal government is also coordinating with the National Disaster Risk Reduction and Management Council (NDRRMC), Phivolcs, and MGB to map out the sinkhole sites and determine long-term measures for community safety.