【摘要】 通过对阿拉善地区地震活动图象呈现显著的条带状、新构造变形表现为块体的隆升和向北的掀斜、周缘和内部性质各异的断裂活动状况、结晶基底与基底内推覆和滑脱构造发育等构造特征的分析，以及与相邻块体的比较，论证了阿拉善活动快体的存在，对其边界作了厘定，并将其归属到华北亚板块。强调了阿拉善块体为一活动构造，其内部存在一个NE向的阿拉善地震带，归属于华北地震区。该地区的地震危险性不可低估。更多还原

【Abstract】 Based on the banded pattern of seismicity, the uplift and northward inclination ofneotectonic movement, the active state of boundary and internal faults, the authorsanalyse the characteristics of crystalline basement, the well-developed nappe structureand detachment of the Alxa region. By comparing with adjacent block, the Alxa blockwas divided and then classified as the North China sub-plate. It should be pointed outthat the Alxa is an active block with a northeast seismic belt in this area. The seismic riskin this area should not be underestimated.更多还原