通过对历史地震资料的系统收集整理、现场调查及烈度点评估等工作，对1936年天水南6级地震等震线重新进行了改绘，并对此次地震的震害特征、等震线特征及其与活动构造间的关系进行了研究。结果表明，此次地震极震区最大烈度为Ⅷ度，集中位于天水镇及其以北地区；NEE向的礼县-罗家堡断裂中东段基本与此次地震重破坏区长轴线重合，应为此次地震的发震断裂；由于受NWW向西秦岭北缘断裂带与NNW向六盘山断裂带2条区域深大断裂及北部黄土区的影响，低烈度等震线长轴方向逆时针旋转，地震动及烈度向北衰减变缓，地震等震线呈现明显的南北衰减不对称性。

We systematically collected and analyzed the historic earthquake record and site investigation of the southern Tianshui M6.0 earthquake in 1936,checked the intensities of the destroyed sites and investigation points and modified the seismic isoseismal lines. The result shows that the epicenter area was located in the region north to Tianshui County and the maximum intensity of the earthquake is Ⅷ. The long axis of the meizoseismal area is about the NEE direction and almost overlapped to the middle segment of Lixian-Luojiabu active fault,which means the fault should be the seismogenic structure of the earthquake. Due to the effect of the north margin fault zone of the west Qinling,Liupanshan fault zone and loess plateau in the north region,the long axis direction of isoseismal line with lower intensity offsets counter-clockwise and the attenuation of intensity and ground motion slows down in the north direction,which causes the asymmetry of the isoseismal lines from south to north. In view of the uncertainty of the study of historic strong earthquake and active tectonic in this region,the research achievement of the southern Tianshui M6.0 earthquake in 1936 has important referential value.

P315

中国地震局地震科技星火计划项目（XH16036）资助