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根据近十年来区域台网的P波初动方向观测资料,得到了鄂尔多斯地块周围13个分区的综合地震节面解;结合已有的结果进行分析,地块周围确实存在有别于华北地区地壳应力场基本情况的小区域应力场:地块西南边缘的六盘山褶皱带处于北东东向的水平挤压应力状态;地块边缘的断陷盆地处于北西向的水平拉张应力状态,尤其是渭河盆地到临汾盆地的主压应力轴已近于直立;地块西北角和东北角处于北西向的水平拉张与北东向的水平挤压共同作用的应力状态;在地块的西面与北面,从北到南和由西往东,主压应力轴的走向由北北东向逐渐转变为近东西向。 此外,还对本文结果在板内动力学中的意义进行了简要的讨论。
According to the observation data of the initial P-wave direction of the regional network in the past ten years, the comprehensive seismic section solution of 13 sections around the Ordos block has been obtained. Based on the analysis of the existing results, The crustal stress field is basically a small regional stress field: the Liupanshan fold belt on the southwestern margin of the block is in the horizontal compression stress state in the NE direction; the fault basin at the edge of the block is in the horizontal tensile stress state in the NW direction, especially The principal compressive stress axis from Weihe Basin to Linfen Basin is nearly upright; the northwest and northeast corner of the block is in the northwest direction and the horizontal extensional stress acts together with the horizontal compression in the north-east direction; on the west of the block With the north, from north to south and from west to east, the direction of the principal compressive stress axis gradually changes from north to north to near east-west. In addition, the significance of the results in the in-board dynamics is briefly discussed.