邓家桥水库地震

EARTHQUAKES(ML=1.9)OF THE DENGJIAQIAO RESERVOIR

摘要:

人工诱发的水库地震问题,已广泛地引起工程地质,水文地质和地震地质工作者的注意。近50年来不少学者对水库地震的成因和诱发机制提出了不同意见,较为一致的是水库地震是一种特殊类型的构造地震,它的特殊之处就在于水对地震的触发作用,这种触发机理只是在活动构造总的地质背景下才显现出来。本文所介绍的邓家桥水库地震就是这种典型震例。

Abstract:

The Dengjiaqiao reservoir is located in Yidu county of Hubei province, and produces a storage capacity of about 4X10⁵M³. since June 1980 rainstorms continuously taken place in the west part of Hubei province. Reservoir was first fully impounded on 31 July of 1980, thus earthquake (M_L=1.9) was induced the next day.
Secimicity of the Dengjiaqiao reservoir is an event of tectonic-earthquakes type, Due to stormily increasing of rainfall and ground water flowing into underground streams, and permeating into fractures, and so pore pressure increased in some faults, and effective normal stress was decreased, In addition, full impounded lodging also made normal stress increase about 1 bar. This resulted in forming a fracture slip of the fault in NE direction.