Page - 456 - in Book of Full Papers - Symposium Hydro Engineering

COMMISSION INTERNATIONALE DES GRANDS BARRAGES ------- VINGT-SIXIÈME CONGRÈS DES GRANDS BARRAGES Autriche, juillet 2018 ------- STUDY ON MECHANISM OF RESERVOIR INDUCED SEISMICITY AND COUNTERPLOTS FOR RESERVOIR OPERATION UNDER EXTREME WEATHER Xinxiang ZENG, Tinggai CHANG, Xiao HU, Lei YANG Earthquake Engineering Research Center, CHINA INSTITUTE OF WATER RESOURCES AND HYDROPOWER RESEARCH CHINA 1. INTRODUCTION The odds of extreme weather events increased significantly recently against the backdrop of global climate change, in which China is one of the most affected countries especially for typhoon and rainstorm. The water level will change rapidly if the typhoon or rainstorm occurred in the reservoir region, which is seemed to increase the occurrence probability of Reservoir-Induced Seismic (RIS). The RIS means typically minor earthquake sequence resulting from reservoir impoundment or variation of water level. The damage of RIS may probably be much bigger than that of natural earthquake because its focal depth is very shallow. Therefore, it is necessary to study the mechanism of extreme weather induced RIS events, as well as provide some corresponding countermeasures for reservoir operation management. Shanxi reservoir is located in the upper stream of Feiyun river (Zhejiang Province, China) with capacity of 18.24×108m3, and the height of the concrete face rockfill dam is 156.8m. Shanxi reservoir region will be affected by typhoon from June to September every year. The impoundment of the reservoir started from May 12th, 2000. And a ML3.5 seismic events in reservoir region has been recorded in July 28th, 2002[1]. From that time on, the induced seismic activity has been an issue for the Shanxi reservoir. 456