On August 28th and 31st,2013,there are 2 major earthquakes with magnitudes of Ms 5.2 and Ms 5.9 respectively occurred in succession at the boundary region among Dêrong county of Sichuan province,Dêqên county and Shangrila county of Yunnan province and followed with a series of afiershocks.The distance between these 2 epicenters are about 10 km.The Dêqên-Zhongdian-Daju fault was the seismogenic structure for the 2 earthquakes,which located in the northwestern boundary of the Sichuan-Yunnan rhombic block.Based on field investigation in the epicenter area,associated with focal mechanisms result of the Shangrila-Dêrong earthquake swarm sequence and the Quaternary active research,the paper revealed and discussed the activity and the behavior characteristics of Dêqên-Zhongdian-Daju fault.This fault performed as high angle thrust along the Waka town to the Tuigai village,which was different from the focal mechanisms result of the Shangrila-Dêrong earthquake swarm sequence,revealing the tensile stress environment in this region,and also different from properties of the dextral strike slip of the Dêqên-Zhongdian-Daju fault.This may be caused by the local effect of strike slip fault when approaching to near-surface.However,it could not represent general kinematics of the fault.The Dêqên-Zhongdian-Daju fault was a Holocene active fault,whose overall performance was obvious dextral strike slip.%2013年8月28日和8月31日在云南迪庆藏族自治州德钦县、香格里拉县与四川甘孜藏族自治州得荣县交界地区发生Ms 5.2、Ms 5.9地震,两次地震相距约10 km,期间又发生多次强余震,该地震的发震构造为川滇菱形块体西北边界的德钦-中甸-大具断裂带.我们通过对震中区断裂的野外地质调查,结合前人对该断裂第四纪活动研究方面的成果,对德钦-中旬-大具断裂带震中区附近的活动性、运动特征等进行了揭示和探讨.野外调查揭示该断裂在瓦卡镇至推改村沿线断裂在近地表为高角度逆冲性质,这与前人对香格里拉-得荣地震群序列的震源机制解研究揭示的该地区拉张应力环境不太协调,也与断裂整体的右旋走滑运动性质不太一致,这可能是由于走滑断裂在走向转变处于近地表形成的局部效应,并不能代表断裂带总体的运动性质.德钦-中甸-大具断裂为全新世活动断裂,总体表现为以右旋走滑为主的运动性质.
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