Signal Analysis on Infrasound and Gravity Waves Received before and after the Lushan Earthquake
详细信息
- 责任者：Zhao Juan (Three Gorges Research Center for Geo-Hazard ; Ministry of Education ; China University of Geosciences ; Wuhan 730074 ; China) ; Zeng Zuoxun
- 刊名：Earth Science Frontiers
- 出版年：2013
- 卷期：20(6)
- 关键词：大震 ; great earthquakes ; 声波 ; acoustical waves ; 四川 ; Sichuan Province
- 页码：p.36-41
- 图表：4 illus., 19 refs.
- 分类号：0500
- issnNo：ISSN1005-2321
- isbnNo：CN11-3370/P
摘要
A couple of days before and after the Lushan earthquake(MS7.0)occurred on April 20,2013,atmospheric pressure perturbations were observed in the Three Gorges Reservoir Area by several infrasound monitors,installed by the Three Gorges Research Center for Geo-hazard.Among the observations,local infrasound and very low frequency gravity waves can be clearly identified.We generated synthetic seismic waves in order to compare it to the air pressure changes,testing the ground-to-air coupling near the infrasound monitor,and found that the correlation between the local infrasound and the vertical movement velocity of the ground is high.We also calculated the azimuth of the gravity wave sources on the basis of a triangle monitor array.The results show that one of the aftershocks(MS4.9)of the Lushan earthquake is the most relevant event to the gravity waves received on April 22,the wave propagation velocity is 9m/s,the calculated azimuth of the wave source is 254.3°,giving a deviation of 13.4°to the practical epicenter azimuth.The Dali earthquake(MS5.1)in Yunan province occurred on April 17is the most relevant event to the gravity waves received on April 18,the wave propagation velocity is about 28m/s,the calculated azimuth of the wave source is 220.2°,giving a deviation of 24.5°to the practical epicenter azimuth.
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