Capitol to assess risks of new sinkhole

CEBU, Philippines - Cebu provincial disaster officers will conduct a risk assessment on the fourth sinkhole found in Badian town, particularly in Sitio Patag, Barangay Bugas, in a bid to reduce risks to human, property and environment.

The sinkhole measures seven feet wide and seven feet deep and is situated about a hundred meters away from the nearest village.

 "We will still have to check and assess the risk it poses to the community," said Julius Regner, spokesman of the Cebu Provincial Disaster Risk Reduction and Management Office (PDRRMO).

 With the conduct of such risk assessment, Regner said it will determine their next action, particularly on implementing mitigating plans and pre-cautionary measures.

 Regner said the southern towns of Badian, Moalboal, Malabuyoc and Alegria have several sinkholes and probable sinkhole sites.

 In February this year, the Mines and Geosciences Bureau disclosed that they have been monitoring over 100 sinkholes all throughout the province.

The MGB-7 has identified Badian town and its neighboring towns as prone to sinkholes since their soil composition is dominantly made of limestone.

MGB-7 chief geologist Al Emil Berador explained that sinkholes are natural formations that occur when limestone deposit dissolve gradually after contact with rain and circulating groundwater.

Berador said most of the areas in Cebu province are composed of limestone deposits. In fact, he assessed that about 60 to 70 percent of localities in Cebu are made up of limestone.

MGB-7 has commissioned its supervising geologist, Josephine Aleta, to lead a team to check the site and investigate further the circumstances that led to the collapse.

The team reported that they discovered a big cavern measuring approximately three to five meters forming below the ground surface; the sinkhole measured seven meters deep with an elongated hole of about five to seven meters.

It also reported that there was no water found in the sinkhole.

MGB-7 has described sinkholes as one of the geological hazards that happen when carbonate rocks are dissolved by water.

The dissolved carbonate rocks create cavernous space underground forming caves. The ground from above will collapse when there is no longer underground support.

Sinkholes can also occur if a corroded limestone area is disturbed by natural tremors such as earthquakes or by human induced activities, including blasting.

Engineer Loreto Alburo, regional director of MGB-7, encouraged town and barangay officials of Badian to continue monitoring the area and set up warning signs to warn the public of possible hazards near the sinkhole. (FREEMAN)