中国活动构造与地震活动

ACTIVE TECTONICS AND EARTHQUAKE ACTIVITIES IN CHINA

文中研究了中国活动构造与地震活动的关系 ,包括活动断裂、活动褶皱、活动盆地和活动块体与地震活动的关系。全部 8级、绝大部分 7～ 7.9级地震均发生在活动块体边界活动构造带内 ;但对内部有次级活动构造的块体而言 ,少数 7～ 7.9级地震和部分 6～ 6 .9级地震也可能发生在块体内部的活动构造带上。大地震与活动断裂、活动褶皱和活动盆地的关系十分紧密 ,70多次 7级以上地震的同震破裂带及其位移参数与活动构造完全一致 ,7～ 8级地震均发生在活动断裂、活动褶皱和活动盆地带内 ,仅个别地震由于发生在高原和高山区 ,情况不明 ,6～ 6 .9级地震则大约有 5 %～ 15 %发生在活动构造带外或者情况不明。由于中国各断块区应力环境的差别 ,各区活动构造变形和地震发震构造类型也有所不同 ,文中对不同构造区走滑型 ,逆断裂褶皱型和正断裂拉张型活动构造和地震发震构造模型作了讨论。

In this paper we have studied the relationship between the active tectonics and earthquake activities in China. Active tectonics includes the structures of active faults, active folds, active basins, and active blocks. All earthquakes of magnitude over 8 and most of earthquakes with magnitudes 7 to 7.9 occurred along the boundaries of active tectonic blocks. A few earthquakes of magnitudes 7 to 7.9 and some of those 6 to 6.9 were distributed along the active tectonic zones in the interior of tectonic blocks. Great earthquakes were closely linked with active faults, active folds and active basins; the co-seismic ruptures and displacements of more than 70 historical earthquakes were consistent with these active tectonic zones. Except a few earthquakes occurred in the interior of high mountains and plateau; most earthquakes of magnitudes 7 to 8 occurred along active faults, active folds and active basins. 5%~15% of earthquakes of magnitudes 6 to 6.9 were not associated with active tectonic zones, or their causal relationships with active tectonic zones are unknown. Because the stress environment differs from one tectonic block to another, active tectonic deformation and types of seismogenic structures are also different. In the paper we have discussed the seismogenic models and active structures of strike slip faulting, reverse faulting-folding, and normal faulting-extension in different tectonic block regions.