The Mines and Geosciences Bureau – Central Visayas has confirmed a sinkhole formation in an agricultural land in the Bugas, Badian town, southwest of Cebu.
A section of a farm in sitio Purok 2 recently collapsed into a sinkhole.
A team from MGB-7 led by supervising geologist Josephine T. Aleta conducted an investigation in the area and found a big cavern hollow measuring three to five meters below the ground surface has formed. The sinkhole is seven meters deep with an elongated hole of about five to seven meters.
There was no water found in the sinkhole.
The town of Badian and its neighboring towns sit on a limestone area and is prone to sinkholes.
“Sinkholes are natural formations that occur when limestone deposits gradually dissolve after a contact with rain or circulating ground water,” chief geologist Al Emil Berador explains.
MGB-7 Regional Director Loreto B. Alburo asked the local government unit of Badian to continue monitoring the area and set up warning signs to warn the public of possible hazards near the sinkhole area.
Sinkholes, considered as a geological hazard happen when carbonate rocks are dissolved by water. This slow geological process, is often unnoticeable.
The dissolved carbonate rocks create cavernous space underground forming caves. When there is no longer underground support, the ground from above will collapse. It can also occur if a corroded limestone area is disturbed by natural tremors such as earthquakes or by human-induced activities, including blasting.
Berador said majority of the areas in Cebu have limestone deposits. About 60 to 70 percent of Cebu including areas that are habitable such as urban areas, is composed of limestone.