Results of the analysis of field survey data and historic literature documents in Vietnam reveal that there is evident of past tsunami attacking Vietnamese coast. However, the evident is still not strong enough to confirm the occurrence of past tsunami events in Vietnam. On the other hand, results of preliminary paleo-tsunami study also show that there are possibilities of tsunami occurrence at Vietnam coast in the past. The analysis on the seismic activities and structure of tectonic plates in the South China Sea (SCS) reveals that there are four areas in the sea with possibilities of having tsunami earthquakes. Based on the computed results by validated models on the generation of the tsunami by earthquake and the propagation of tsunami in the SCS, it was found that significant tsunami at Vietnamese coast could be generated by an earthquake with magnitude of larger than 7 at the fault along Central Vietnam shelf, and by an earthquake with magnitude of larger than 8 at the Manila Trench. If an earthquake with the magnitude of 7.5 happens at south Hainan Island, the maximum height of tsunami at Vietnamese coast can be more than 1.5m. If the earthquake with magnitude of 8.5 happens at Manila Trench, the maximum tsunami height from Da Nang to Quang Ngai can be more than 4m, and at some places, can be more than 5m. The coast with the maximum tsunami height of more than 1m stretches about 1000km, from Quang Binh to Binh Thuan. Then, it can be concluded that the risk of tsunami in Vietnam is not very large, but exists, and it is necessary to prepare for the disaster.
