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Tsunami warning and forecasting(2)

2019-01-11  |   Editor : houxue2018  

Japan's tsunami warning mechanism is well developed and mature. In 1983, a tsunami occurred in the sea of Japan near Hokkaido, seven minutes after the earthquake, the magnitude of the epicenter was determined, fourteen minutes later, the tsunami warning was issued, at that time, as long as you pick up the phone, the Telephone Bureau first asked you to listen to the tsunami warning, then you can dial the phone. Television and radio broadcasts were interrupted and repeated warnings, so that the notified coastal population could quickly evacuate to the Highlands without causing casualties. Tsunami drills are held every year in Japan, and evacuation routes are well known.

Tsunami is a complex problem, some earthquakes may cause tsunamis, but most ocean earthquakes do not necessarily cause tsunamis, therefore, false reports often occur. From 1949 to 1996, the Pacific tsunami prediction center issued a total of 20 tsunami warnings, of which 15 did not occur, making them false. In recent years, with the development of numerical simulation technology, the prediction accuracy has been improved significantly. At present, the prediction work mainly focuses on the following four aspects: tsunami generation mechanism, numerical simulation of tsunami occurrence, installation of early warning systems of several deep seabed seismographs, and rapid release of early warning information.

Shortly after the Indian Ocean tsunami, on 13 January 2005, Annan, then Secretary-General of the United Nations, called for the establishment of a global disaster early warning system to prevent natural disasters such as tsunamis, storm surges and tornadoes at the meeting of small island States held in Port Louis. Annan said:“The tragedy of the tsunami once again tells people that prevention and early warning must be done well. "We need a global warning system that includes not only tsunamis but all other threats, like storm surges and tornadoes, in carrying out this work, no part of the world should be neglected", he said.

Extended reading

Tsunami early warning system

Tsunamis usually occur on the coast near the Pacific Rim Seismic Zone, therefore, countries (regions) bordering the Pacific Ocean have established effective tsunami warning systems, which are well known to the local people (Fig. 5-3). The last tsunami on the coast of Sumatra and the entire Indian Ocean was caused by the eruption of Krakatoa in 1883. Therefore, the heavy casualties caused by the earthquake and tsunami, due to the local people did not come across nearly a hundred years of lack of awareness of the tsunami, therefore, the Indian Ocean coastal countries (regions) did not attach importance to the threat of tsunami and did not establish an effective tsunami early warning system.

Figure 5-3 International tsunami Icon

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