In which cases shall a tsunami warning be issued in Vietnam?

In which cases shall a tsunami warning be issued in Vietnam? (Internet image)

Regarding this issue, LawNet would like to answer as follows:

1. In which cases shall a tsunami warning be issued in Vietnam?

A tsunami warning shall be produced for:

- Earthquakes with a magnitude of more than 6,5 (according to Richter magnitude scale or equivalent magnitude scales) which occur at sea and may cause a tsunami that affects Vietnam.

- Tsunamis caused by earthquakes at remote sea that potentially affect Vietnam.

(Article 31 Decision 18/2021/QD-TTg)

2. Types of tsunami warnings in Vietnam

- Tsunami warnings shall be classified into 3 levels:

+ First-level tsunami warnings, which shall be issued as soon as a strong earthquake and probability of tsunami are detected and people are advised to prepare for evacuation;

+ Second-level tsunami warnings, which shall be issued as soon as a non-destructive tsunami and probability of rough and damaging waves in coastal areas are detected and people are advised to prepare for evacuation;

+ Third-level tsunami warnings, which shall be issued as soon as a destructive tsunami is detected and immediate evacuation is required.

- Broadcasts on tsunami warning cancellation

A broadcast on tsunami warning cancellation shall be produced when the tsunami did not happen as warned.

- Final tsunami broadcasts

The final broadcast on a tsunami shall be produced when the tsunami is fully gone.

(Article 32 of Decision 18/2021/QD-TTg)

3. Contents of tsunami warnings in Vietnam

- Headlines: tsunami warning according to regulations in Article 32 of this Decision.

- Tsunami assessment

+ Location, duration, intensity, coordinates of epicenter and focal depth of earthquake;

+ Probability of tsunami, severity level and area directly threatened by tsunami;

+ Wave height at coasts and duration of effect.

- Evacuation scale depending on warning level.

- Tsunami severity level according to regulations in Article 4 and Article 56 of this Decision.

- Time of broadcast.

- Names and signatures of persons responsible for making broadcasts.

(Article 33 of Decision 18/2021/QD-TTg)

4. Policies on transmission of tsunami warnings in Vietnam

- For Voice of Vietnam and Vietnam Television

+ Earthquake broadcasts shall be transmitted once immediately after receipt and replayed in the next news broadcasts;

+ First-level and second-level tsunami warnings shall be transmitted immediately after received and replayed twice with 5 minutes interval between each instance. Repeat every 30 minutes until the final tsunami broadcast or tsunami warning cancellation broadcast is received;

+ Third-level tsunami warnings shall be transmitted immediately after received and replayed twice with 5 minutes interval between each instance. Repeat every 20 minutes until the final tsunami broadcast is received;

+ The final tsunami broadcasts or tsunami warning cancellation broadcast shall be transmitted and broadcasted once after received and replayed in the next news broadcasts.

- For Vietnam Coastal Communication Systems and tsunami warning systems

+ First-level and second-level tsunami warnings shall be transmitted immediately after received and replayed twice with 5 minutes interval between each instance. Repeat every 15 minutes until the final tsunami broadcast or tsunami warning cancellation broadcast is received.

+ Third-level tsunami warnings shall be transmitted immediately after received and continuously replayed with 5 minutes interval between each instance until the final tsunami broadcast is received;

+ The final tsunami broadcast or tsunami warning cancellation broadcast shall be transmitted and broadcasted once after received and replayed once after 5 minutes.

(Article 37 of Decision 18/2021/QD-TTg)

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