Stay 30 meters away from sinkholes—MGB

A government geologist said sinkholes in Cebu island were a normal occurence.

But geologist Al Berador warned people to stay at least 30 meters away because the ground depression could recur and worsen.

“We discourage the public from residing in limestone areas because we don’t know if there are caverns under the surface,” said the chief geologist of the Mines and Geosciences Bureau.

“Cebu is composed of 60 to 70 percent limestone so sinkholes are possible,” he said.

The MGB has yet to visit Barili town in southwest Cebu to verify if the phenomenon in the boundary of barangays Nasipit and Mantayupal is caused by a sinkhole

Barili residents were alarmed when the water flowing in a river was “sucked up” by what looked like a sinkhole that a farmer saw last Tuesday.

Sinkholes are topographic depressions formed as underlying limestone bedrock is dissolved by groundwater.

Unlike in other extreme natural events like typhoons and tsunamis, where advisories are issued by authorities, there is no available technology in the country to detect, forecast or warn for possible sinkholes.

“Sinkholes can happen in any limestone area, be it flat or mountain. But the more aged the limestone is, the most susceptible it is for sinkholes,” said Berador.

“There are times when cracks precede a sinkhole in the same way there are also times that the soil collapses in an instant,” he explained.

The MGB is sending a team of geologists today to investigate the Barili incident.

The Barili municipal government sent policemen to cordon the area after dumping filling materials in the site.

The Barili sinkhole is the third reported this year after similar phenomenon in southern towns of Dumanjug and Dalaguete early this year.