银川盆地地壳稳定性分析

Analysis on Crustal Stability in Yinchuan Basin

银川盆地地质构造复杂,地震活动频繁.为评价该区域地壳的稳定性,用重力资料解译3条北西断裂,并结合已有的构造认识,讨论深部构造样式和浅部断裂的空间展布特征及活动性,以及地震活动特征、大地形变特征及区域地球物理场特征;用模糊数学的综合评价模型将银川盆地按照77个待评区进行分区评价.结果表明,银川盆地总体处于稳定与不稳定之间;贺兰山断裂、黄河断裂附近以及盆地的中部贺兰等地区,由于断裂活动性强、构造复杂,深部构造交汇等特征,稳定性相对较差,而盆地的北部和南部稳定性则相对较好.

Yinchuan Basin is complex in geologic structure with frequent earthquake activities. To evaluate the regional crustal stability, the article interprets 3 north-west breakages with gravity data, and discusses deep structure type and superficial fracture’s spatially distributing feature and activity and the seismicity feature, the ground deformation, and regional geophysical field feature based on existed structure knowledge;it divided Yinchuan Basin into 77 parts for evaluation with comprehensive assessment model of fuzzy mathematics. The result shows that, the overall Yinchuan Basin lies between stability and instability;the stability is poor in the area of Helanshan breakage, the Yellow River breakage area, and the middle part of basin- Helan area with the features of strong fault activity, complex structure, and intersection of deep structure, the north and south of the basin, however, is relatively good in stability.