关键词: 大桥水库, 水库诱发地震, 加卸载响应比, 地震预测

Abstract: The water level annual change in Daqiao reservoir is about 40m,which imposes a static pressure change on its basin about 4?10⁵Pa,100 times as the role of earth tide.Therefore,the water level's change becomes the largest force source of loading or unloading effect on its basin.In this paper,we apply Load-Unload Response Ratio(LURR)theory on studying LURR value's changes pre-and after the M_s 4.6 Daqiao reservoir earthquake using earthquake number and energy data.The results show that:in the vicinity of the reservoir,for small earthquakes occurring in the reservoir water loading process,the earthquake number LURR value Y_n and C_r appeared as high-value anomalies,indicating that the rock in the study area was in a state close to failure,and then the M_s 4.6 reservoir earthquake occurred;the average value of Y_n and C_r showed significant difference before and after the impounding, as was high-value anomalies before the reservoir impounding,and resumed to normal afterwards. This case shows that reservoir water level's LURR could be beneficial to reservoir earthquake's monitoring and forecast.

Key words: Daqiao reservoir, reservoir-induced earthquake, LURR, earthquake forecast