The development and collapse of an underground karst cave caused a depression in An Tien Commune, My Duc District in Hanoi on April 2, experts said.
A scene of the depression in My Duc District in Hanoi, which was caused by the development and collapse of an underground karst cave.
These experts, from the Hanoi Department of Natural Resources and Environment said after researching the field today that the terrain was quite complicated and they could not measure the exact depth of the cave.
The Union of Survey Construction Companies (USCO) proposed to fill up the hole with stones and concrete and signed an agreement with scientists and the municipal authorities.
The work was estimated to cost VNĐ1 billion (US$44,400).
Deputy Director of the Hanoi Department of Natural Resources and Environment Nguyen Van Hung asked the organisations concerned to assign workers to keep a close watch to prevent accidents to residents.
Earlier on April 2, a loud noise occurred at 8.30am in An Tien Commune. A hole with a diameter of nearly 10 metres formed on a road and partially damaged some houses belonging to Nguyen Van Bac, a local resident, and some of his neighbours. No one was injured.
VNS