【摘要】 为了研究区域构造应力场与地壳构造运动及地震的关系,我们在华北及郯庐断裂带进行了原地应力测量。本文仅就华北地区和郯庐断裂带的实测结果,讨论华北和郯庐断裂带现今构造应力埸的特征, 华北地区的应力测量结果表明:虽然各测点的最大主应力方向并不完全一致,但从整个区域来看,最大主应力的优势方向为北西西到近东西向,实测结果与地震地质调查结果一致, 郯庐断裂带各测点主应力的大小和方向变化较大,但是离断裂带较远的测点,其最大主应力的方向仍然反映了近东西向的压应力作用。郯庐断裂带各测点剪应力的大小与离断裂带的距离有关,这同美国圣安德列斯断裂带的测量结果相类似。从原地应力测量资料还可以看出,经过大地震以后,震中区测得的主应力值和剪应力值比震中周围地区的测值低,且主应力的方向与区域构造应力场的方向有较大的偏离,反映了地震过程中应力的释放和调整。应力测量结果还表明,虽然我们的测量大都是在地表下三十米以内的浅部进行的,但测得的最大主应力方向的分布是有一定规律的,与地质构造和地壳运动有一定的关系,浅部原地应力测量结果是能够反映区域构造应力埸的作用特征的。更多还原

【Abstract】 For the purpose of studying the action features of tectonic stress field, wehave made in situ stress measurements in North China and Tancheng-LujiangFault Zone. Keeping the whole region in view, we can see that the stress field in theearth’s crust in North China is compressive and the predominant direction ofits principal stress is NWW to EW, although the directions of the maximumprincipal stress are not entirely the same at each locality. The magnitudes and directions of the principal stress at sites in Tancheng-Lujiag Fault Zone are different each other. It is evident that the directions ofσ_Hmax near the fault zone are quite different from those relatively far fromthe fault zone The later are also nearly NWW to EW. The magnitudes ofshear stress are related to distance to the fault The influence of active faulton stress field in this region is similar to that of the san Andreas Fault Zonereported by Zoback M. D. etc. It is obvious that absolute values of the principal stress and the shear stresswithin the epicentral region observed after a strong earthquake are usually lessthan those from the surrounding areas. The directions of maximum principalstress also had a great change. It may be shown that stresses had been releasedand adjusted during and after the strong earthquake. The results show that the in-situ stress measurements in shallow boreholecan reflect the features of tectonic stress field.更多还原