A growing body of evidence suggests that a massive landslide between Barangay Gaway-gaway in San Remigio and Barangay Anonang Sur in Bogo City triggered by the 6.9-magnitude earthquake that struck northern Cebu late last month-has caused artificial damming, raising alarms over potential flash floods, karst subsidence, and widespread displacement.
The warning came from former Mines and Geosciences Bureau (MGB) chief geologist Liza Socorro Juanico Manzano, following the circulation of photos showing submerged homes and rising water levels in the upland Tigib area.
Manzano explained that artificial damming occurs when landslide debris blocks a river channel, causing water to accumulate upstream.
‘If left unaddressed,’ she warned, ‘this can lead to destructive flash floods or debris flows downstream-especially during heavy rainfall, when river energy and sediment loads are elevated.’
She also raised concerns about karst subsidence, a scenario where ponded water infiltrates underground fissures and tension cracks, potentially weakening sinkholes and cave systems. Manzano stressed the need for immediate removal of debris and urged close coordination with MGB Region 7 to assess risks and identify vulnerable communities.
The images that prompted Manzano’s assessment were posted by vlogger Nicodimo Saguirel, who documented the aftermath of the landslide and described the area as ‘a lake in the making.’ His photos showed destroyed and submerged homes, with water steadily rising across the upland basin. Similar images and videos from local residents have also circulated online.
San Remigio Vice Mayor Alfie Reynes Corominas confirmed that the local government was alerted immediately after the earthquake that preceded the landslide.
The Municipal Engineering Department and the Disaster Risk Reduction and Management Office (DRRMO) were dispatched, but Corominas admitted that the situation was too complex and dangerous for municipal teams to handle alone.
Mayor Mariano Martinez has sought assistance from the provincial government, which has since deployed additional personnel. Despite partial clearing in nearby zones, however, the Tigib accumulation remains inaccessible.
Corominas explained that the site lies between two steep mountains with unstable limestone (locally called ‘anapog’) deposits that continue to shift due to aftershocks.
She warned that any hasty intervention, such as blasting, could worsen the situation and endanger responders.
Councilor Lou Ornopia, chair of the infrastructure committee, confirmed the situation and disclosed that during their exit conference with the MGB, the agency advised keeping the area off-limits for at least six months.
However, with water levels continuing to rise, Ornopia supported Manzano’s assessment that the impounded water poses a growing threat.
He described the site as originating from a ‘sapa’ (creek), where water from rains since the September 30 earthquake has continued to accumulate-forming what he now calls a ‘lake’ from the collapsed portion of the mountainous terrain spanning Bogo and parts of Tabogon.
He warned that if the natural dam gives way, downstream barangays-including coastal and agricultural zones-could suffer severe flooding.
‘Cornfields, coconut groves, and low-lying communities are already showing signs of overflowing water,’ Ornopia said.
He added that he has asked the Department of Public Works and Highways (DPWH) to install a reversible pump to help relieve water pressure.
‘Nihangyo ko from DPWH na butangan lang gyud siyag reversible pump mintras di pa gyud mataak. In six months, mas dako ang posibilidad nga mubuto na diha, mas dako ang risk nga mga tawo sa ubos nga barangay grabe kaayo ang kadaot. Dili lang ta magpaabot na wa tay buhaton. maoy bisan pasuyupan na lag tubig,’ Ornopia said.
On a positive note, he has also reached out to the National Irrigation Administration (NIA) to explore the feasibility of constructing a dam in the area.
Meanwhile, the municipal government of San Remigio has issued a public advisory urging residents to avoid sinkholes and tension cracks, and to refrain from building or dumping waste near these features. The LGU also reiterated the MGB’s reminder for vigilance, especially in areas affected by recent seismic activity.
Emergency hotlines have been activated, and preemptive evacuation orders have been issued for residents in Barangay Tacup and parts of Gaway-gaway. Authorities continue to monitor the situation closely, calling for public cooperation and technical support to prevent further loss and ensure community safety.