Tsunami warning rehearsal in Vietnam

The hypothetical scenario is that an earthquake struck the deep-sea area in Manila, Philippines, at 8:45am. The hypothetical tsunami is forecast to affect the area from Da Nang to Quang Ngai, with wave heights of over five metres, between 10:30 and 12:30. Immediately, experts proposed issuing tsunami warnings to the entire coastal area of Vietnam, while notifying localities and vessels to wait until the threats are over, before making their way back to the shore. The warning messages will repeat every fifteen minutes, until the tsunami warning is over, which is also the end of the rehearsal.