Around 3,000 people, including over 2,100 police officers and soldiers will take part in a tsunami exercise in the central city of ${bigcity_Da_Nang:"Da Nang"} on October 7, 2011. According to a meeting of the tsunami exercise organizing board on August 3, the circumstance of the exercise would be an earthquake of 8.6 to 8.8 Richter scales appeared in the western sea of the Philippines in the morning of October 7. After three hours, tsunamis of 5-6m high hit ${bigcity_Da_Nang:"Da Nang"} city.

Some coastal areas in ${bigcity_Da_Nang:"Da Nang"} flooded at the depth of 2-3 meters. Many houses and trees collapse. Traffic is in chaos. Many visitors and fishermen are in danger in the sea and need urgent rescue.

Being warned of tsunamis, coastal observation stations timely process and convey information to related agencies. Ships, helicopters and specialized vehicles are sent to the tsunami-hit areas to save people.

According to the organizing board, the exercise aims to check the operation of the country's tsunami warning system and to improve skills of the various groups and authorities in responding to a disaster.

Vietnam Institute of Geophysics' Earthquake and Tsunami Warning Center deputy director, Nguyen Hong Phuong said the institute had created 25 scenarios to prepare for tsunamis.

Those scenarios were based on nine tsunami sources which could affect the country's coast, Phuong said. The most dangerous source was the subduction zone Manila in the west of Philippines.

The two other dangerous areas were the fault lines off south-central Vietnam and the Riukiu area of Taiwan, he said.

According to the Ministry of Natural Resources and Environment, a magnitude 8.3 earthquake in Manila could cause a 6.2m tsunami in central Quang Ngai province and a 2.1m tsunami in central Khanh Hoa province's Nha Trang city. A magnitude 9.2 earthquake could cause 10m and 5m tsunamis in those two places respectively.