دانلود رایگان مقاله انگلیسی زمین لرزه در شهرستان جیوژایگو در شمال سیچوان، چین در 8 اوت 2017 - اشپرینگر 2018

Abstract

Jiuzhai Valley National Park in the Aba Tibetan and Qiang Autonomous Prefecture of northern Sichuan, China, is well renowned both at home and abroad as ‘‘World Natural Heritage,’’ ‘‘Man and Biosphere Conservation Network’’ and ‘‘National GeoPark of China.’’ An earthquake with a magnitude of 7.0 struck Jiuzhaigou County on the evening of August 8, 2017. Its focal depth was 20 km and followed thousands of aftershocks. The earthquake had affected 17 townships and 120 villages in varying degrees. By the 8 p.m. on August 13, the death toll of the earthquake reached 25, with 525 injured. Being formerly described as ‘‘Fairy tale world,’’ ‘‘King of waterscape,’’ the beautiful scenic spot now had become ‘‘scars of wounds strung together like beads,’’ and some of the beauty even disappeared. In this short communication, the incident background, casualties and scene are presented. Moreover, a brief investigation on the cause and seismic damage capacity of the earthquake as well as the earthquake early warning is conducted.

4 Discussion and summary

Sichuan Province locates in the seismically active region of mainland China. The earthquake damages in history had been prominent, and this situation is still severe at present. Timely warning before earthquake is crucial to reduce economic losses and casualties in seismic areas, while pre-earthquake warning now is still a worldwide problem. Adequate response time before earthquake coming particularly can effectively guarantee evacuation and reduce casualties. In this serious earthquake disaster, its necessity and remarkable effect were verified by earthquake early warning system (EEWS), which was initiated by the 2008 Wenchuan earthquake and developed by Institute of Care-life (ICL) in Chengdu, Sichuan Province (Fig. 8).

EEWS, a system based on a network including monitoring stations for seismic waves, by using the fact that the electric wave speed is much faster than the S waves speed, can give seconds to dozens of seconds warning time prior to the arrival of S waves. The obtained warning information includes the estimated intensity and arrival time of S waves as well as the estimated magnitude and location of the epicenter. In Jiuzhaigou earthquake, 19, 48, 49, 71 s before the earthquake waves spread to Longnan City in Gansu Province, Aba Tibetan and Qiang Autonomous Prefecture, Mianyang, Chengdu, respectively, the EEWS released warning information through various means such as computers, micro-blog and special acceptance equipment, which was beneficial to reduce the disaster damage.