The Mines and Geosciences Bureau (MGB-6) has found 88 sinkholes in the town of Buenavista, Guimaras.
In a press briefing held Wednesday at the MGB-6 office in Iloilo City, MGB Regional Director Leo Van Juguan said the preliminary report of the detailed Karst subsidence assessment that was conducted from September 2 to October 7, 2015, found 88 sinkholes and 85 caves in 17 barangays in the town of Buenavista.
Sinkholes are ground depressions or openings formed when the underlying soluble rocks are dissolved, resulting in voids underground which can weaken the support for the overlying surface.
According to MGB-6, the karst subsistence assessment found the presence of sinkholes in the following barangays: Agsanayan, Dagsaan, Daragan, Getulio, Mabini, Montpiller, Navalas, New Poblacion, Salvacion, San Isidro, San Miguel, San Pedro, San Roque, Tacay, Taminla, Tastasan, and Zaldivar.
Subsidence due to sinkhole collapse is one of the most dangerous geohazard because of its extreme unpredictability.
This information can be used by local government planners and individual landowners to make decisions on where to build dwellings and other structures.
In the Philippines, subsidence hazard in karst terrain have not been given much attention in the past until the strong earthquakes in Negros Oriental in 2012 and Bohol in 2013 exposed the numerous sinkholes in these areas.
These phenomena were proven destructive and have affected built-up communities, roads, schools, administrative buildings, and agricultural farmlands.
The recognition of the devastating damage that can result from this hazard and the presence of extensive karst areas in the country prompted MGB of the Department of Environment and Natural Resources to include karst subsidence assessment in the National Geohazards Mapping and Assessment Program. PIA-6