基于向量扫描法的微地震震级确定方法

A method to estimate the microseismic magnitude based on vector scanning

对地震记录中显著可视事件震级的确定,已有如里氏震级、矩震级、不同定义的震级之间的关联、震级与能量之间的关系等成熟方法。然而,由于微地震事件记录常淹没在背景噪声中,无法实施包括确定震级在内的传统定位。为比较不同类型不同地域的微震大小、研究微震机制及诱发原因、使用其安全预警等,我们外延里氏震级到微震范畴,定义了等效里氏微震震级:根据微破裂向量扫描输出的无量纲能量或最小信噪比,估计一定时空中单位时间单位台站所接收的在时空目标一点上的等效能量和震级。文中列出了目前我们在微震监测中发现的几类微震的大小规模。

The magnitude of a seismic event can be estimated by measuring seismic energy,seismic moment,and relationship between the energy and seismic magnitude(M),etc.However,it is impossible to traditionally locate a microseismic event,including determining its magnitude,because its records are submerged in the background noise in most of cases.Comparing the microseismic magnitudes at different regions and with different causes,studying their mechanisms,we first extend the definition of the Richter magnitude to the microseismic range.Then,based on the scanning output of the minimum ratio of signal-to-noise in the available vector processing for microseismic monitoring,we estimate their equivalent Richter magnitude.The microseismic magnitudes induced by different causes are compared.