Coastal erosion possible cause of suspected sinkhole in GenSan

GENERAL SANTOS CITY (MindaNews/17 February) — The suspected sinkhole that appeared near a coastal community here over the weekend and triggered the evacuation of 46 families could be a case of coastal erosion, the Department of Environment and Natural Resources’ Mines and Geosciences Bureau (MGB) in Region 12 said.

Roger Tamayo, MGB-12 mining engineer, said their initial assessment showed that the huge hole that developed at the shores of Purok Tinago in Barangay Dadiangas South here could have been caused by the degeneration of coralline limestones situated underneath the area’s shoreline.

He said the breakdown of the limestones might have triggered the erosion of its sand covering that eventually appeared liked that of a sinkhole.

“(But) this is just our initial or partial assessment. We have no basis for now to conclude what really happened here as that can only be made through further geological assessment,” he said.

MGB Region 12 director Constancio Paye Jr. sent Tamayo and his team to assess the site on Monday and verify whether it was indeed a sinkhole.

The suspected sinkhole, which was initially estimated at around 40 meters in diameter, emerged early Sunday morning, prompting the city government to order the forced evacuation of 46 families settled near the area.

The 206 evacuees are currently taking temporary shelter at the covered court of the Irineo Santiago National High School here.

Citing their assessment, Tamayo said the shoreline opening could not be considered a sinkhole as there was no “igniter” like an earthquake that happened before it emerged.

He said its likely cause could be coastal erosion as it appeared that there is already a pattern of such phenomenon in the area.

“According to some residents, this is the third time that happened in the area these past years,” he said.

Tamayo explained that coralline limestones or fossils are natural features in some coastal areas.

In parts of the Visayas, he said the coralline limestones have led to the emergence of small islets, and with trees and plants growing in some due to their sand covering.

But the official said they will still confirm their assessment through the agency’s geologists, who are currently attending a training in Manila.

He said the geological study will be aided by the agency’s ground penetrating radar, which will specifically determine what is underneath the opening.

In the meantime, Tamayo advised the city government to keep a close watch of the site and prevent anybody from getting near as it is “very dangerous.”

He said the nearby community should remain off limits to residents pending the conduct of the geological assessment.

The affected area is located near the pier and anchorage area of motorboats ferrying passengers and cargo to and from this city and Balut Island in Davao Occidental.

It is adjacent to the city’s Queen Tuna Park and several commercial establishments, including a hotel and a gasoline station, as well as a crowded residential community. (MindaNews)