THE 135 sinkholes found in the Island Garden City of Samal (Igacos) can be "dangerous" but will definitely not cause the collapse of the island, Mines and Geosciences Bureau (MGB)-Davao Region Geosciences Division officer-in-charge Abigail Agoc said.
Thus, MGB officials advised residents to immediately cordon off any sinkhole they may find before someone falls into it.
"Maging vigilant na bantayan ang signs kung may mga movements or may mga circular depression sa area, kung may mga sinkholes, cordon agad (Be vigilant and check for signs of movement or circular depressions in the area, if there are sinkholes, cordon them). Avoid disposing garbage and waste water," said MGB-Davao Region acting information officer Lowell Chicote, in Wednesday's Habi at Kape at the Abreeza Ayala Mall.
There are residents who have made sinkholes water or garbage receptacles. Chicote said this should not be done as it will contaminate the water below.
Chicote said that sinkholes can be expected in the island city because the soil composition in Igacos is limestone, a weak material susceptible to constant collapse of the soil's surface layer.
"Nangyayari yan sa mga limestone areas, kase kapag natatamaan sa tubig, nalulusaw. Meron kaming deep penetration radar para magkaroon ng findings sa mga sinkholes," he said.
In a study conducted by the Department of Environment and Natural Resources and MGB in 2015, most of the areas within Igacos are prone to subsidence hazards except for limited locations in the northeast of the island.
Agoc said they expect more sinkholes to appear in the next two to three years. But, he said, that contrary to some people's beliefs, this will not cause Samal to collapse.
"Samal is an island, dili na siya mag-collapse despite the gradual increase of sinkholes (It won't collapse despite the increase in sinkholes)," Agoc explained.
Chicote advised Igacos residents to monitor the signs, should there be sinkholes and tension cracks that are progressing. He also said that it is best to avoid building infrastructure projects near those areas.