Experts: ‘Boiling water’ caused by recent quake
Geologists said “boiling water” found in the sinkhole in Dumanjug town, Cebu, was not caused by volcanic activity.
It may be caused by a “liquifaction process,” said Dr. Arturo Daag, chief science research specialist of the Geology and Geophysics Division of the Philippine Institute of Volcanology and Seismology (Philvocs).
Daag made the disclosure amid the discovery of another developing sinkhole in barangay Casay, Dalaguete town in southeast Cebu.
He said the boiling seawater in the Dumanjug sinkhole is a normal post-earthquake incident.
“After the Feb. 6 earthquake, the underground pressure changed and also caused changes on ground compression. The water in the subsurface also changed direction,” Daag said.
He explained that the pressure that causes water to come out of the sea and resembles “boiling water” occurs between the layer of sand and soil in the subsurface.
“It is not volcanic activity. Most of the soil composition in Cebu is limestone. The land alteration caused this incident and not any volcanic activity,” Daag said.
The nearest volcano is Mt. Canlaon in Negros Oriental.
Residents in barangay Looc, Dumanjug town, have been visiting the sinkhole after spotting what looked like boiling water.
A Philvolcs team from Manila was unable to assess the area during their first visit since it was high tide at the time.
In Dalaguete town, the Mines and Geosciences Bureau of Central Visayas (MGB-7) said the six feet deep sinkhole in barangay Casay is in the middle of tall grasses and can’t be seen from a distance.
“It used to be an intermittent creek where water would pass through during rainy days. It is a limestone area and the soil is very permeable,” said MBG-7 senior geologist Al Emil Berador.
The sinkhole is three minutes away from the highway in barangay Casay and the nearest house is about 300 meters away. A resident identified as Noelito Entoma first found the sinkhole on Feb. 8.
He said he always passed through the area to gather wood and he was shocked when he saw the large hole in the area, which ate up their pathway.
Geologists said the sinkhole is 7.5 meters wide and six meters deep.
Since they have no equipment to asses the extent of the gaps underground, Berador said they will monitor the area in the meantime.
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