Home World News Hualien earthquake unlikely to cause tsunami, analyzed by Chinese scholars at University of Southern California

Hualien earthquake unlikely to cause tsunami, analyzed by Chinese scholars at University of Southern California

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Hualien earthquake unlikely to cause tsunami, analyzed by Chinese scholars at University of Southern California

At about 5 pm Western time on the 2nd (7:58 am on the 3rd Taiwan time), a strong earthquake of magnitude 7.2 struck Hualien, with a magnitude of 6.5.University of Southern California(USC)EarthquakeScientist Professor Li Yonggang analyzed that the maximum shock is no less powerful than the main shock, but currently it seems that the probability of triggering a tsunami is low. In contrast to Southern California’s recent relative calm, new research finds that earthquakes in the San Andreas Fault Zone are related to the amount of water in nearby inland lakes.

Li Yonggang said that the frequency of earthquakes has increased recently in Taiwan and the Philippines. The epicenter of the Hualien earthquake was inland. In the past, most earthquakes were offshore, so this earthquake was felt strongly. Usually in islands, seismic waves propagate deep underground, so the destructive force on the ground is not as great. At present, it seems that the epicenter is not very serious, but the largest shock is about 6.5 magnitude. Although both earthquakes differ in intensity, due to differences in depth and distance, both earthquakes produce similar amplitude ground vibrations.

He said secondary damage caused by the Hualien earthquake still needed to be observed. The slopes in the Hualien area are very large and steep, and coastal roads can be swept away by stones. If it rains, the weather will be even worse. Regarding concerns about tsunamis, he believes that several key conditions must be met for a tsunami to occur. First, the intensity is substantial, but this earthquake is not at sea level and inland; Secondly, the focal mechanism. This earthquake is related to a thrust fault. The Tohoku earthquake in Japan that caused the first tsunami, both the earthquake and the Indonesian earthquake are reverse faults. In general, because the earthquake is not located on the seabed, the tsunami threat is not very high at present, and the sea water in HualienCaliforniaThe destructive power of an earthquake will decrease with the depth of the ocean water as it deepens.

In contrast, the California Fault Zone is not a thrust fault, but a horizontal scissor cut. Therefore, no matter how severe the California earthquake is, it will not cause a tsunami. Li Yonggang said that California has been relatively quiet recently. The San Andreas Fault, which is the area of ​​concern, typically causes a major earthquake every 250 years, but it has not caused a major earthquake in 330 years. A recent study from UC San Diego and San Diego State University in the journal Nature found that there is a Salton Sea inland lake along the Andreas Fault, and a connection between the inland lake’s water content and earthquakes. The maximum depth of the lake could reach 95 metres, and its surface area would be 14 times that of today. When the lake water fills to a certain amount, it will trigger a magnitude 8 earthquake. There are no earthquakes anymore because the lake water has reduced the load, the load has become smaller, and the pressure on the ground has also become smaller. Although there has been a lot of rain this year, the amount of water is at least 14 times less than before.

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