CEBU CITY – Cornelia Tines looks out the window every night, unable to sleep since the day a sinkhole appeared on a farm 50 meters away from their house. Her fears grew when a pool of water appeared at the bottom of the hole.
“Ang akong kahadlukan kay basin musulbong ang tubig (What I fear is that the water may rise),” said the 44-year-old mother of six. Their house is located on a hill overlooking the farm.
“Kung molunop, usa gyud me sa akong pamilya sa mangamatay. Simbako lang (If a flash flood occurs, I and my family will be among the casualties. God forbid).”
On Monday, geologist Abraham Lucero Jr. of the Mines and Geosciences Bureau (MGB) Central Visayas inspected the sinkhole in Barangay Camboang, Dumanjug town.
When it was discovered by the farm’s caretaker last Thursday, the sinkhole was just the size of a big cauldron. It was 10 by 8.5 meters wide and 3.5 meters deep on Monday.
Lucero, MGB’s senior science research specialist, warned the sinkhole may still get bigger.
The sinkhole, he said, may have occurred when the roof of an underground cave collapsed after the magnitude 6.9 earthquake last February 6 and the rain last week.
“It’s a natural phenomenon in areas where the rock formation is limestone,” Lucero said.
According to MGB, approximately 70 percent of the total land area of Cebu is covered by limestone materials.
The water coming out of the sinkhole in Barangay Camboang, Lucero pointed out, could be an indication of an underground river.
Some residents also reported the presence of a small hole on the shore in Barangay Looc, which is near the town proper. Hot water, they said, flows out of the hole.
Lucero said residents noticed it two days after the earthquake last February 6. The geologist, however, was not able to see the reported hole because it was high tide.
The geologist recommended that local officials put a fence around the sinkhole in Barangay Camboang to keep onlookers away. The presence of onlookers puts more pressure on the ground.
Dumanjug Mayor Nelson Garcia said he will order a barbed wire screen around the sinkhole, which swallowed a small mango tree and a wooden post. He also asked the village chief to have the area monitored by tanods 24 hours a day.
The farm, owned by a Swedish national married to a Cebuana, is five meters away from barangay road and one kilometer from the national highway.
Walter Pesalbon, the farm’s 36-year-old caretaker since 2007, said the hole was the size of a cauldron when he discovered it Thursday afternoon.
He blamed the earthquake and the rain for the formation of the sinkhole.
Lucero said the exact situation underground can be determined through a ground penetrating radar system, a technology the MGB lacks. The equipment, he said, is available in Manila.
Mayor Garcia said the MGB, an attached agency of the Department of Environment and Natural Resources, should bring the equipment to Cebu, so the area can be assessed thoroughly.
“We want to know how far this hole will go so that we in Dumanjug will be prepared,” he told Lucero. “There is an urgent necessity for you to bring the equipment as soon as possible.”
Garcia said Cebu City and the province should purchase the equipment, given that the island is made mostly of limestone.
“This is an eye-opener for the city and the province,” he said.
On Monday, many curious onlookers gathered around the sinkhole. The police had put a yellow line around it. A man selling boiled peanuts took advantage of the crowd.
A group of old residents huddled near a small mango tree, two meters away from the hole.
“Karon pa ko ani kakita (It’s my first time to see something like this),” said 72-year-old Celso Alpuerto, who lives 100 meters away from the sinkhole.
He was born and raised in the village. The earthquake last February 6, he said, was the strongest he has ever felt.
“Matapos na ta ini tingali (Maybe our time is near),” he said. (Sun.Star Cebu)