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利用在怀来附近布设的中-欧合作小孔径数字化地震台网的资料,以相对定位法测定了1995年7月河北沙城地震群的震源位置,用理论地震图拟合了P波、S波最大振幅比值,反演了震群54个地震的震源机制。从三维空间上分析了沙城震群的震源位置、震源机制,认为震源断层是NE向高倾角右旋走滑断层,并将其与宏观调查结果、地质活断层等作了对比。研究后认为:沙城震群发生在地壳浅层NE向地质断层延伸和扩展的新破裂上,属于现代地壳应力场作用下浅层断层发育过程中的地震。文中讨论了作者所提出的利用地震序列的震源分布和震源机制资料分析震源断层的意义。
Based on the data of the small-bore China-Europe cooperative small aperture digital seismic network laid near Huailai, the relative location method was used to determine the focal position of the Shacheng earthquake group in July 1995, and the theoretical seismic images were used to fit the P wave, S wave The maximum amplitude ratio inverses the focal mechanism of 54 earthquakes in the swarm. From the three-dimensional space, the source location and focal mechanism of the Shacheng earthquake swarm were analyzed, and the hypocenter fault was interpreted as a NE-trending right-angle strike-slip strike-slip fault and compared with the macro-survey results and the geologic active fault. After the study, it is concluded that the Shacheng earthquake swarm occurred on the new fault that extends and extends from the shallow NE geologic fault in the crust and belongs to the earthquake in the process of shallow fault development under the stress field of modern crust. The paper discusses the significance of using the source distribution and source mechanism data of seismic sequences proposed by the authors to analyze focal faults.