At an international conference on Thursday on earthquake risk in Viet Nam, Cao Dinh Trieu, vice chairman of the Asian Earthquake Association, warned that Ha Noi, HCM City and southern Ba Ria-Vung Tau Province were all located in special zones at risk of an earthquake falling between 5-7 degrees on the Richter scale.

"If the epicentre is in the centre of the cities, 30-40 per cent of houses and buildings would collapse," Trieu said.

The north and south of the country have felt murmurs from earthquakes in China and the East Sea in recent years. Trieu added that the Geophysics Institute had developed a detailed earthquake risk map for Viet Nam.

Apart from "hot spots", there were around 30 regions throughout the country at risk of an earthquake of 5 degrees on the Richter scale, he said.

According to the institute’s research, there are nearly 1,600 earthquakes in Viet Nam ranging from 3 degrees on the Richter scale upwards between 1114 to 2003.

Deputy Director Nguyen Hong Phuong of the Viet Nam Tsunami Warning and Earthquake Information Centre said earthquakes were rare, but if one did occur there would be serious damage.

Disaster readiness measures are important. Earthquakes are in fact difficult to forecast, but having a plan for how to cope with the effects is important.

"We can establish measures ahead of time for how to cope with an earthquake when it happens. For example, we can develop earthquake-resistant standards for construction projects and build a special forces unit to provide emergency relief for consequence mitigation," he said.

Authorities should also strengthen the controls over the implementation of earthquake-resistant construction standards, Phuong said.

"Authorities should raise awareness and education among the public about the issue, because most of the population is unaware of earthquake prevention measures," he said.

Pr William L Ellsworth from the US Geological Survey said that earthquakes posed a great threat to the life of people and countries, and he urged Viet Nam to build "a culture of preparations" to cope with a disaster.

Trieu said construction project investors must consider earthquake-resistant designs and make efforts to define the levels of damage the buildings would suffer in the case of an earthquake.