昔格达断裂晚第四纪活动特征及强震复发周期

Activity Characteristics on the Xigeda Fault in Late Quaternary and Recrudescing Interval of Strong Earthquake

利用冲沟、山脊等断错构造地貌的DEM影像资料和详实的野外踏勘,详细分析了昔格达断裂的晚第四纪活动特征。结果显示：断裂线两侧的河沟和山脊地貌呈＂S＂或反＂Z＂形或以多个首尾连接的＂S＂形雁列式斜列,断裂活动为左行左列式,断层上发育多个拉分盆地和断裂湖;该断裂最新活动时间晚于（12.83±1.09）ka,为全新世走滑活动断裂,倾滑分量不大,倾向总体西倾,且晚更新世以来的左旋走滑速率约为1.70 mm/a;依据断裂线地震遗迹及断裂活动特征,断裂强活动复发间隔大致为10~12 ka或更短。

The paper studied the Late Quaternary activity of the Xigeda fault carefully based on the geomorphologic analysis of the landsat ETM data combined with field tectono-geomorphic observations and measurement.Results reveal that shape of the rivers and ridges along the fault showed the ＂S＂ or anti-＂Z＂,or more ＂S＂shape,which are end to end connected with each other,and an echelon oblique columns;the faulting way is sinistral strike slip with left step,and a series of pull-apart basins and fracture lakes（lake distributed popularly）developed;that as Holocene active strike-slip fault,its latest active time was later than（12.83±1.09） ka,generally,which is west dipping,with smaller（trend） strike-slip component and slip rates of 1.70 mm/a since late Pleistocene;that according to the seismic remnant and active characteristics of the fault,recrudescing interval of the fault activity is 10-12 ka or shorter.