Abstract: This paper deals mainly with the geotectonic background of the seismicity in the Tancheng-Lujiang fault zone, with emphasis on the relationship of Late Quaternary active faults in southern part of its middle segment to the earthquakes. The seismicity is clearly different in various segments, this is well correlated to the difference of geotectonic units with various characteristics and faulting activities in the Late Quaternary.The evidences on the intermittent motion (stick-slip motion) of the active faults found in the southern part of the middle segment can be regarded as a geological indicator to discriminate the paleo-earthquakes and to estimate roughly their recurrence. It is clear that this indicator is of practical significance for evaluating the seismic tendency of the active fault zone. In the meantime, by the geological and seismological analogues the authors propose that in the same tectonically active zone where occurred strong historic or prehistoric earthquakes, exists a possibility of recurrence of earthquakes in the same location. However, it is to be noted that some segments of this zone, where the tectonic conditions are similar in occurrence of earthquakes and evidences of intermittent motion of active faults since Late Pleistocene are found and where seismic gaps last more than two thousands years, can be referred to the temporal "quiet segment". The earthquake risks in these segments may actually be rather serious than that in the segments with recent activities. Therefore, we had better not say the former segments to be more safe in the near future. It has already been verified by the fact that in the recent /ears quite a few strong earthquakes took place in the historical seismic gaps being tectonic-ally newly-reactivated. In conclusion, to make the seismic zonation more exact it should pay attention to the investigation of the geologico-geomorphological evidences on recurrence of large earthquakes in the active fault zone within plates.

摘要： 本文概述郯城-庐江断裂带地震活动的地质构造背景和第四纪晚期断层新活动与地震的关系。指出沿带地震活动性具有明显的分段性,这与各段位于不同性质的大地构造单元和第四纪晚期断裂活动的差异性有较好的相关性。活断层粘滑运动的遗迹,是鉴别古地震及其重复发生的一种地质标志。同一活动构造带,强震有原地重演的可能。晚更新世以来发生过断层的粘滑运动,而二千多年来又无强震的“地震休眠段”,其危险性将比历史地震区(段)更紧迫。必须考查板内活断裂带强震重复活动的地质-地貌标志和年代学的研究。