Do Thi Yen Ngoc was not surprised when the Swan (Thien Nga) Islet, a famous limestone pinnacle resembling the elegant waterbird, collapsed recently in the bay of Bai Tu Long.
“We had studied the islet thoroughly and checked its cracks. Then we identified collapse threats,” said the geologist at the Vietnam Institute of Geosciences and Mineral Resources.
Her institute conducted a two-year research project that concluded in 2012 about the risks of losing 11 popular islets in Ha Long and Bai Tu Long bays, including the Swan.
The bays, close to each other, are known worldwide for thousands of limestone islets and karsts in various shapes and sizes, but there seems to be a lack of efforts to preserve them.
Can Dinh Loan, a photographer, told the media last week that he found out about the collapse of the Swan during a trip to the bay in June.
The islet, rising about 15 meters above the water, has lost the part resembling the swan’s neck and head.
Ho Tien Chung, another geologist from the institute, said the islet was formed by limestone layers of 10-20 centimeters thick stacking on top of one another.
“The layers were affected by waves, wind and plants' roots and gradually came apart,” he said, blaming the collapse to natural erosion.
He said the institute’s scientists have proposed general solutions, including strengthening the foundations of the islets or building breakwaters to keep strong waves from directly hitting them.
Tran Tan Van, director of institute, said lesser-known islets have partially collapsed but not many people are aware of them.
Among them was the islet numbered 649 in Ha Long Bay, he said, adding that it collapsed in 2013.
Van proposed drilling through the remaining limestone layers of the Swan and fastening them together.
“The important thing is that whether relevant agencies are determined to take action and how much they want to invest in the work,” he said.
A file photo of Thien Nga (Swan) Islet before the collapse. Photo: Can Dinh Loan