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本文指出,1932年昌马7.5级地震的地面破裂带(即地震断层)主要是由三条大型反S形压扭性地裂缝带呈雁列构造形式组合而成,显示出地震破裂带具有左旋走滑性质。它们代表了一条属于北北西向构造隆起带的北西西向剪切面。由于北东东—南西西向压应力的作用,这一剪切面主要是沿着早期(古生代)昌马断裂带显示出来的。因此这些主要的地震裂缝,是昌马第四纪活断层剪切作用的直接反映。此外,文章还探讨了活动断裂带中成为危险地段的某些地震地质标志,并进行了区域构造应力场分析。
This paper points out that the ground rupture zone (ie, earthquake fault) of the 7.57 Changma earthquake in 1932 is mainly composed of three large-scale anti-S-shaped fractures of geostrophic tectonism, showing that the rupture zone of the earthquake has a left- Slippery nature They represent a northwestern-west shear plane belonging to the north-northwest tectonic uplift. This shear plane is mainly shown along the early (Paleozoic) Changma fault zone due to compressional stress from NEW to SWW. Therefore, these major seismic fractures are the direct reflection of shear in Quaternary active faults in Changma. In addition, the paper also discusses some seismic geological signs that are dangerous in the active fault zone and analyzes the tectonic stress field in the area.