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Tsunami is an important marine disaster in the world, according to statistics, since the beginning of the 21st century, more than 250,000 people have died or gone missing worldwide. After the 7.6-magnitude earthquake in the Noto area of Ishikawa Prefecture, Japan, Japan and many surrounding countries issued a tsunami warning. How are tsunami warnings issued, and what should individuals do in the face of a tsunami?
How does a tsunami warning system work?
Tsunamis are mainly due to destructive wave processes caused by submarine earthquakes, volcanic eruptions, submarine landslides, etc. Tsunamis can be divided into three categories according to their causes: seismic tsunamis, volcanic tsunamis, and landslide tsunamis. More than 80 per cent of tsunamis are reported to be caused by earthquakes. Tsunami areas around the world are roughly consistent with seismic zones.
After the strong earthquake that struck the Noto Peninsula in Ishikawa Prefecture, Japan, the Japan Meteorological Agency issued a tsunami warning for the coastal areas of the Sea of Japan, calling on residents in the relevant areas to evacuate as soon as possible. What is the relevant principle of tsunami warning? According to the understanding, the speed of seismic waves is much faster than the speed of tsunamis, and it is completely possible to make predictions and early warnings of tsunami by using the time difference, and earthquake and tsunami can quickly determine the seismic parameters according to the seismic monitoring system, and then carry out early warning and prediction of tsunami events caused by earthquakes. The communication system can transmit tsunami information in real time to the countries or regions where the tsunami may reach, and evacuate people through warnings and other measures in time.
How to avoid danger in the event of a tsunami?
Although a tsunami disaster is a rare event, a tsunami can have serious consequences. It is understood that when a tsunami siren is sounded or the ground shakes or abnormal waves appear on the sea surface, it is necessary to leave quickly and evacuate to the nearest high place or along the evacuation route. After evacuating to a safe place, pay attention to the tsunami warning information at all times, and do not return to the shore until the tsunami warning is lifted.
For ships at sea, the velocity of the tsunami is much smaller in deep water than in the port, and it is safer to be in deep water. If the vessel happens to be in deep water, don't rush back to port and stay in a safe area with a depth of more than 300 meters.
At present, the mainland's self-developed tsunami early warning system has been officially put into operation, which can obtain real-time tide level observation information from more than 300 stations in 65 coastal countries around the world, realizing real-time monitoring and early warning for the world.
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Real Xi Editor: Angel