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 hadpreceded 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, NamCuong group, and the building investor, Song Da Thang Long Joint StockCompany, which was working in a project next to the hole, were seekingindependent consultants to identify the cause of the collapse.
Meanwhile, the road investor has been ordered to stop water flowinginto the hole and ensure drainage for surrounding areas and open analternative route for traffic.
Song Da Thang Long has been told to consolidate foundation to prevent further sinking and torestore the water supply system. It was also ordered to build up part ofthe hole by August 25 to allow traffic to pass.
TheTransport Engineering Design Corporation has been asked to propose waysto fix the hole, also experts are concerned that continued rain willhamper construction work.
Previously, the depressionwas alleged to have been a result of poor quality construction on thenearby site by Song Da Thang Long.
Meanwhile,Associate Professional Nguyen Dinh Hoe, of the Vietnam Association forConservation of Nature and Environment, said that the3,000-cubic-metre-hole that took form between August 19 morning andAugust 20 afternoon might be the result of geological faults slidingwithout causing an earthquake.
This was evidenced bythe disappearance of road-building materials including soil and sandwith an average speed of 100 cum per hour, he said, adding that thematerial must have sunk downward.
Hoe also mentionedthe collapse of a dyke and other underground construction in thesouthwest of Hanoi as it is located inside the fault zone of Hong(Red) River and Chay River .
“It is easy toidentify the presence of geological fault around the hole,” he said,warning about the consequences of active faults on the area in thefuture.-VNA