明龙山-上窑断裂是一条逆走滑性质的第四纪活动断裂,长约68kin,走向300°-315°.本文在卫星影像解译的基础上,通过野外调查,确定了该断裂的几何展布和分段特征,初步将断裂分为明龙山、上窑、凤阳山3条次级断裂段.通过对断裂经过处的采石场进行详细追索,我们对典型断层剖面进行了描述并采集了断层泥ESR样品,得到的测年结果为(243±24) ka和(126±15) ka,由于淮南地区是典型的中等强度地震活动区,断层晚第四纪以来活动强度较弱,这些测年结果虽不能代表断层最后一次微弱活动的时代,但可以确定断层最后一次强烈活动时代为中更新世晚期至晚更新世早期.结合前人对1831年风台Ms61/4级地震极震区位置、等震线形态研究及本文对极震区附近断裂展布和活动性的对比分析,我们认为明龙山-上窑断裂为本次地震发震构造的可能性最大.%Extending with a strike direction of 300°-315° and a total length of 68km,Minglongshan-Shangyao fault kept active in strike slip mode with thrust component since Quaternary.Based on interpretation of satellite images and detailed field investigation,we identified the spatial distribution and segmentations of the fault.This fault consists of three secondary faults,namely Minglongshan segment,Shangyao segment and Fengyangshan segment.Field geological survey at quarries along the fault was carried out including profile description and ESR samples collecting.Dating ages of ESR samples turn out to be (243 ± 24) ka and (126± 15) ka.As Huainan area is dominated by moderate earthquakes and faults in this area are not very active since late Quaternary,these dating results cannot be considered as the occurrence time of the most recent earthquake event.However,the most recent strong movement of this fault is dated back to late period of middle Pleistocene and late period of early Pleistocene.Combined with previous studies on location and delineation of magistoseismic area of the 1831 Ms6 1/4 earthquake in Fengyang,we propose that Minglongshan-Shangyao fault is most likely to be the seismogenic structure for this earthquake based on detection and analysis of faults and activity around the magistoseismic area.
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