鄂尔多斯地块北缘动力背景和现今地震活动特征

鄂尔多斯地块的动力背景是青藏高原东北缘NE向推挤作用的结果。1970年以来，鄂尔多斯地块北缘现今地震活动表明，中强地震活动具有幕式活动特征，从1970~2015年共经历了4幕活动；块体西北缘与东北缘的中强地震具有迁移对跳活动特征，1970年以来共经历了4组对跳；震例统计结果揭示，地块北缘6.0级左右地震前，块体中等地震经历长时间平静具有普适特征；2005-03以来，块体所在的阴山地震带再次进入中等地震超长平静时段。其幕式活动特征、迁移特征、时间平静特征可作为区域范围强震的预测指标。

Dynamic Background and Present Seismic Activity Characteristics in the Northern Margin of the Ordos Block

The research results show that dynamic background of the Ordos block is the Tibetan plateau compression from an East-West direction. The seismic activity of the Ordos block northern margin since 1970 shows that the moderate seismicity is characterized by episodic activities; moderate earthquakes of Ordos block experienced 4 curtains from 1970 to 2015, strong earthquakes of the northwestern and northeastern margins of the Ordos block has migrating characteristics, a total of 4 curtains since 1970, (before the magnitude 6 earthquake in the northern margin of the block). The moderate earthquake of the entire block has been quiet a long time according to the statistical results of earthquake examples, while moderate seismic is in a long quiet stage in Yinshan seismic zone since March 2005. The curtain activity and migrating characteristics, as well as the time calm characteristics, can be used as a prediction index for strong earthquakes in the region.