Quake-stricken areas tagged as high-risk zones due to danger of ground collapse

Local

THE earthquake may be over, but the ground under parts of northern Cebu is still moving, and it could give way.

The Department of Environment and Natural Resources in Central Visayas (DENR-7), through its Mines and Geosciences Bureau (MGB), has issued a Subsidence Threat Advisory warning of ground collapse in several towns following the 6.9-magnitude tremor that struck the region earlier this week.

San Remigio, Medellin, Bogo City, Tabogon, and Daanbantayan have been tagged as high-risk zones for subsidence after sinkholes and land depressions were confirmed in multiple barangays.

“The recent seismic activity has destabilized ground conditions, resulting in the formation of sinkholes in certain affected areas,” the MGB said. “Ground cracks and depressions were also noted nearby, indicating potential progression of the subsidence.”

MGB-7 directed local governments to immediately restrict access to sinkhole sites and crack-prone zones, placing warning signs and barriers to keep residents safe.

Authorities were also cautioned against backfilling or covering sinkholes without proper assessment, especially in areas with underground rivers, as this could worsen collapse or trigger flooding.

Other recommendations include continuous monitoring of cracks after rainfall, discouraging construction in affected areas, and conducting geotechnical studies to guide relocation or engineering solutions.

In San Remigio alone, Mayor Mariano Martinez earlier said over 100 sinkholes may exist across the town, many of which only became visible after the quake. At least 15 were confirmed in Sitio Sansan, Barangay Maño, forcing more than a thousand residents to evacuate to open fields.

Two technical teams from MGB-7 and its central office are on the ground conducting geohazard assessments, which will help determine safety measures, land-use restrictions, and possible relocation sites.

MGB-7 urged communities to immediately report new cracks, sinkholes, or ground depressions to authorities. Families living near unstable terrain are strongly advised to evacuate and avoid using structures built close to the affected areas.

“Affected zones are considered hazardous and require immediate precautionary measures,” the agency said. “Sinkhole development could progress through time as an increase in rainfall, lowering of the water table, or strong earthquakes could trigger further collapse.”

The DENR stressed that the subsidence hazard is an ongoing risk, not an isolated event, as aftershocks and heavy rains could worsen ground instability in the coming weeks.

“Strict and continuous implementation of the recommendations cited above is highly advised,” the agency warned. “The safety of the public depends on proactive monitoring, information dissemination, and adherence to geohazard warnings.”

A full geohazard assessment report is expected once field validations are complete.(TGP)