Torrential rain from tropical storm Kai Tak had led to the collapse of part of the road in Hanoi’s Le Van Luong Street on August 18 leaving a 5m-deep hole measuring 20m by 30m, municipal Transport Department said.

The hole has closed the road to traffic from the city central to Ha Dong District over the past few days.

At the department meeting on August 21, representatives said rain had preceded the collapse, which broke underground water pipes and sewerage, but the cause was yet to be investigated.

Department Deputy Director Nguyen Hoang Linh said the road investor, Nam Cuong group, and the building investor, Song Da Thang Long Joint Stock Company, which was working in a project next to the hole, were seeking independent consultants to identify the cause of the collapse.

Meanwhile, the road investor has been ordered to stop water flowing into the hole and ensure drainage for surrounding areas and open an alternative route for traffic.

Song Da Thang Long has been told to consolidate foundation to prevent further sinking and to restore the water supply system. It was also ordered to build up part of the hole by August 25 to allow traffic to pass.

The Transport Engineering Design Corporation has been asked to propose ways to fix the hole, also experts are concerned that continued rain will hamper construction work.

Previously, the depression was alleged to have been a result of poor quality construction on the nearby site by Song Da Thang Long.

Meanwhile, Associate Professional Nguyen Dinh Hoe, of the Vietnam Association for Conservation of Nature and Environment, said that the 3,000-cubic-metre-hole that took form between August 19 morning and August 20 afternoon might be the result of geological faults sliding without causing an earthquake.

This was evidenced by the disappearance of road-building materials including soil and sand with an average speed of 100 cum per hour, he said, adding that the material must have sunk downward.

Hoe also mentioned the collapse of a dyke and other underground construction in the southwest of Hanoi as it is located inside the fault zone of Hong (Red) River and Chay River .

“It is easy to identify the presence of geological fault around the hole,” he said, warning about the consequences of active faults on the area in the future.-VNA