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Tsunami Preparation  Twitter

Mechanism of tsunami generation

@Seabed rises due to the occurrence of a subduction zone earthquake.
ASea level rises with the rise in the seabed.

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BA tsunami is generated in accordance with the rise in sea level.

・Mega swells, long wavelength

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CAfter the first wave, the second and third waves attack in succession.

・The tsunami piles up as this process is repeated.

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DArrival of a Tsunami

・The wave height increases when a tsunami approaches a coast (i.e., when the water depth reduces).

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※Differences between a tsunami and a normal wave

A normal wave is generated by wind blowing over the sea surface.

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Nomal wave

・A higher part of the wave goes beyond a sea wall.
・Sea level does not change.

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Speed of tsunami

・A tsunami can in the open ocean can travel with speed of greater than that of a jet airplane.

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A tsunami can move from one side of the Pacific Ocean to the other side.

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Tsunami Safety Tips

・If you feel strong shaking or weak ground motion for an extended period in a coastal area, or if Major Tsunami Warning/Tsunami Warning is in effect, do not approach coastal area;

・Major Tsunami Warning/Tsunami Warning is issued by TV,radio and,the Internet/disaster management radio communications systems and so on.

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・You should leave coastal or riverside areas immediately.
Do not engage in fishing or swimming activities until Advisories are cleared.

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・You should evacuate to a safer place such as high ground ,tsunami evacuation tower or an tsunami evacuation building.

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・Remain on alert until the warning is cancelled, as tsunamis may strike repeatedly.

・As long as you have time and strength in reserve, you should evacuate to a safer place.

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(Links)

Tsunami Warnings/Advisories, Tsunami Information
(Japan Meteorological Agency)

Twitter

Fire and Disaster Management Agency
1-2 Kasumigaseki 2-chome, Chiyoda-ku.
Tokyo 100-8926, Japan. Phone:+81-3-5253-5111
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