Class 6.9 Earthquake: Why is Hualien, Taiwan?Why is there a sense of shock in Hangzhou high -rise buildings?

According to the China Earthquake Network, at 14:44 on September 18, 2022, a magnitude 6.9 earthquake occurred in Hualien County, Hualien County, Taiwan (23.15 degrees north latitude, and 121.30 degrees east longitude), with a depth of 10 kilometers. The earthquake is located in Hualien County, about 541 kilometers from Wenzhou City, Zhejiang Province, and about 794 kilometers in Hangzhou. At the time of the earthquake, Wenzhou, Taizhou, Ningbo, Hangzhou, Jiaxing, Lishui and other regions in Zhejiang Province all had earthquake reports. The 6.5 magnitude earthquake from Taitung County, Taiwan on September 17, was 14 kilometers away from the earthquake.

Relevant experts from Zhejiang Earthquake Administration explained the public's doubts:

Why are there many earthquakes in Taiwan?

Taiwan Island is located at the junction of the Eurasian sector and the Pacific sector. It is one of the most intense segments on the Western Pacific Earthquake Bands. In addition to the strong earthquakes, there are deep -source earthquakes in the eastern waters. So far, there are 33 proven activity faults. Earthquakes are frequent, especially in the eastern earthquake activities of Taiwan than western Taiwan. Since the records, nearly 300 magnitude 6 to 6.9 earthquakes occurred in Taiwan and the surrounding waters, with more than 40 magnitude 7-7.9 earthquakes, and magnitude 8 or more earthquakes.

The faults of the eastern part of Taiwan are strong. The breaks are mainly distributed on both sides of the Huadong Ridge Valley and the Ridge Valley. The Handong Ridge Valley is the collision junction of the Eurasian and the Pacific plates. Due to the squeezing each other in the two sections, the earthquake activities are very frequent. A magnitude 6 to 6.9 earthquake occurred more than 200 times, and more than 30 magnitude 7 to 7.9 earthquakes. The magnitude 8 or more occurred in the eastern part of Taiwan.

The fracture of western Taiwan is mainly located in the Taiwan West Plain. The earthquake movement is weaker than in the eastern part of Taiwan. A magnitude 6 to 6.9 earthquake occurred in nearly a hundred times, and a magnitude 7-7.9 earthquake. A magnitude 7.6 earthquake in Jiji Town, Nantou County, Taiwan on September 21, 1999 was an earthquake caused by the Canpu Fracture activity in western Taiwan.

In the Taiwan earthquake, why is there a high -rise building in Hangzhou, but the ground does not feel?

This is because the seismic waves generated during the earthquake have passed through long -distance transmission, and its high -frequency component (short cycle wave) has gradually decreased. When reaching Hangzhou, the earthquake waves are mainly low -frequency wave (long cycle), and the wavelengths are long. The higher the floor, the more the vibration cycle of the building will be similar to the cycle of these earthquake waves. The resonance phenomenon occurs, and the vibration will be obvious.

In addition, because the foundation foundation in Hangzhou is mainly deep and soft, it has a significant amplification effect on the earthquake waves. As soon as the earthquake, the high -rise building with a self -containing cycle of the vibration cycle is easy to resonate with the long -term earthquake waves that have been softened. Even if the magnitude of the earthquake is small or the epicenter distance is far away, it can cause a strong earthquake reaction of high -rise buildings on the venue. Therefore, the Taiwan earthquake, Hangzhou, 800 kilometers, has a clear sense of earthquake.

But don't worry, the seismic design and materials of high -rise buildings have stricter requirements, which is stronger than ordinary buildings. Therefore, when an earthquake occurs, if you live in the high -level, do not rush to run out, do a good job of "Voldemort, cover, grasp", and then evacuate and evacuate after the earthquake.

- END -