首页|期刊导航|中国地震研究：英文版|Intensive Observation of Reservoirinduced Seismicity and Preliminary Analysis on the Causes of Earthquakes in the Three Gorges Reservoir Area, Yangtze River
中国地震研究：英文版2011，Vol.25Issue(3)：273-285,13.
Intensive Observation of Reservoirinduced Seismicity and Preliminary Analysis on the Causes of Earthquakes in the Three Gorges Reservoir Area, Yangtze River
Intensive Observation of Reservoirinduced Seismicity and Preliminary Analysis on the Causes of Earthquakes in the Three Gorges Reservoir Area, Yangtze River
摘要
Abstract
In accordance with the requirements of the National Key Technology R＆D Program of the 11th ＂Five-year Plan＂, a densified seismic network consisting of 26 seismic stations was established at the Three Gorges Reservoir area in the section of Hubei Province in March 2009 （21 short-period seismographs, 5 broadband digital seismographs）. From March to December, 2009, a total of 2,995 ML -0. 8 - 2. 9 earthquakes were detected during the trial impounding of the Three Gorges Reservoir （ water level rose from 145 m to 172.8m）. Using the double difference earthquake location algorithm, 2,837 earthquakes were precisely re-located. The results show that the pattern of small local earthquake swarms in the Three Gorges Reservoir area took on a linear distribution or mass-like cluster distribution, the mass-like clusters of events were generally within a distance of 5 km from waterfront, and the linear distribution of the earthquakes could be extended to a distance of 16 km away from the waterfront. In the Hubei section of the Three Gorges Reservoir, earthquakes were mainly concentrated in the northern end of the Xiannvshan and Jiuwanxi faults near the Xiangxihe River, and along the banks of the Yangtze River at the west of Xietan township and the Shenlongxi area on the northern bank in the Badong region, with focal depths less than 10km, and 4km in average. Earthquake frequency in the reservoir region had a positive correlation with reservoir water level fluctuations, indicating that the seismicity belongs to reservoir induced earthquakes. Along the Shenlong River in the reservoir area, earthquakes showed three linear distributions in the northern Badong county, and distributed according to Karst distribution. There are underground rivers in the carbonate strata. When the reservoir was impounded, water permeated into the underground rivers, thus inducing earthquakes. Earthquakes in the areas on the crossriver segment of Xiannvshan fault, the Jiuwanxi fault and at the areas west of Xietan, Shazhen and Xizhen, may be related to the softening of discontinuities, such as the Nukou fault, the Xiannvshan fault, or the bedding joints, which would lead to failure of rock masses, thus, inducing earthquakes. However, convincing conclusions about the triggering mechanism still need further study. Additionally, near the areas south of Wenhua and Yanglin of Zigui county and at Rangkou town east of Badong county, mininginduced earthquakes occurred at the mines nearby, and on the shores of the reservoir are some collapse earthquakes.关键词
地震成因/三峡库区/地震活动/长江/水库诱发地震/密集/三峡水库/线性分布Key words
Reservoir-induced seismicity/Observation/Earthquake location/Seismogenesis/Three Gorges Reservoir/Yangtze River分类
天文与地球科学引用本文复制引用
Ma Wentao,Xu Changpeng,Yuan Jingli,Li Hai＇ou,Xu Xiwei,Zhang Xindong,Zhang Lanfeng..Intensive Observation of Reservoirinduced Seismicity and Preliminary Analysis on the Causes of Earthquakes in the Three Gorges Reservoir Area, Yangtze River[J].中国地震研究：英文版,2011,25(3):273-285,13.基金项目
This project was sponsored by the National Key Technology R＆D Program （2008 BAC38 B04) , China.ACKNOWLEDGEMENTS Thanks are extended to Wu Shugui, Song Yanyun, Chen Feng, and Wang Fei of Department of Earthquake Monitoring and Prediction, CEA, Zhang Peizhen, Jiang Zhao, and Yin Gongming of Institute of Geology, China Earthquake Administration, for their leadership and support in the construction and observation of the densified Three Gorges reservoir seismic network. This work was also supported （）
