Source: CCTV news client
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: earthquakes and tsunamis, volcanic tsunamis and landslide tsunamis. According to monitoring, more than 80% of tsunamis are caused by earthquakes, and about 5% of tsunamis due to volcanic eruptions are reported. Tsunami-occurring areas around the world are roughly in line with seismic zones.
Wang Peitao, associate researcher of the Tsunami Early Warning Center of the Ministry of Natural Resources: Tsunami events in the Pacific Rim region can account for about 71%, and the Mediterranean region can account for about 15%. The Caribbean and Atlantic Oceans account for 9 per cent.
Wang Peitao told reporters that the reason why the tsunami process caused by the eruption of the submarine volcano in Tonga caused serious consequences was mainly because the formation of the tsunami caused by the volcanic eruption was more complicated and it was difficult to monitor and warn. Earthquakes and tsunamis can quickly determine seismic parameters based on the seismic monitoring system, and then make early warning and prediction of tsunami events caused by earthquakes. Compared with earthquakes and tsunamis, tsunamis caused by volcanic eruptions have shorter tsunami cycles and greater losses for long-distance propagation. The impact and disaster-causing capacity of local areas close to volcanoes is stronger, and the early warning is more difficult, which is one of the important reasons why Tonga is seriously affected.
How should I avoid danger when a tsunami strikes?
Although tsunami disasters are small-probability events, tsunamis can have serious consequences. So in the face of a tsunami, what can people do to maximize risk avoidance?
Wang Peitao, associate researcher of the Tsunami Warning Center of the Ministry of Resources: When the tsunami spreads to the near shore, due to the shallowness of the water depth and terrain, the wavelength of the tsunami will become shorter, and the speed of tsunami propagation will be reduced. This will cause the energy of the tsunami to increase dramatically in the unit space, causing huge damage to facilities or the environment along the coast.
Wang Peitao told reporters that when he hears the tsunami alarm sound or feels the ground shaking and abnormal waves appear on the sea surface, he must quickly leave and evacuate to the nearest high place or along the risk-avoidance route. After evacuating to a safe place, pay attention to the tsunami warning information at any time, and do not return to the shore until the tsunami warning is lifted.
Wang Peitao, associate researcher of the Tsunami Warning Center of the Ministry of Natural Resources: In deep water areas, the flow rate generated by tsunamis is much smaller than in ports, which is safer in deep water areas. If the vessel happens to be in a deep-water area, do not rush back to port and stay in a safe area with a depth of more than 300 meters.
At present, the mainland has established a relatively complete earthquake tsunami monitoring and early warning system, which can release earthquake and tsunami information for strong seabed earthquakes worldwide within 8-10 minutes. Wang Peitao told reporters that at present, countries are mainly through the improvement of earthquake, tsunami monitoring network, the construction of a rapid and intelligent tsunami early warning system, so as to minimize the impact of tsunami disasters.