1. CO-SEISMIC DISPLACEMENT OBSERVATIONIN IN DECORELATE BELT ALONG SEISMIC FAULT OF 2008 WENCHUAN EARTHQUAKE Qu Chunyan, Zhang Guifang State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration(CEA) Beijing 100029, e-mail: [email_address] 2011.07

3. Tectonic Environment of Wenchuan earthquake Tectonic Environment: Wenchuan earthquake occurred on Longmen Shan thrust fault zone, it bounds between the Tibetan plateau and Sichuan basin, where the topography is high and steep, the vegetation is heavy. This make field investigations very difficult. Thus we used D-InSAR technology to capture the whole coseismic deformation fields. Long Menshan thrust fault zone Consist of 3 brunchs F1 F2 F3 Main shock Tibetan Plateau Sichuan Basin Ms≥6.0 After shock Ms=4.0-4.9 Ms=5.0-5.9 (5.12 2008 ~ 7.5 2008)

5. This Fig is the InSAR mosaic interferometric fringes from 7 data tracks, it shows the coverage scope and pattern of the entire deformation field caused by the Wenchuan earthquake. But We can note along the Northeastern direction from Yingxiu to Qingchuan, There is a clear incoherent zone, showed as the belt region encircled by yellow-dash line. We can not obtain the displacement of this area by InSAR technology. But using offset tracking method ,we can get the larger displacement in incoherent zone nearby the rupture trace. Pink big circle denotes epicenter of the main shock. InSAR mosaic interferometric fringes

8. This Fig show the entire surface rupture trace mosaicked from 7 data tracks along the Yingxiu-Beichuan fault, it indicate the scope and pattern of the surface rupture zone, it starting from about 26km west to Yingxiu town, extending northeast to 7km south of Qingchuan county. The total length of rupture belt is about 238km long. In addition, Along the Guanxian-Jiangyou fault, there is also a rupture belt, it is about 66km long. Mosaic Rupture trace and displacement from 7 data tracks

10. Positions and features of Seg1: (105.130/32.425_104.577/31.966) Segment 1 is from Suhe to Chengjiaba, about 75km long, it is straight and narrow , with bigger deformation amplitude in north wall, and broad and weak deformation in south wall. Seg.1 Positions and features of Segment 1

11. Seg.2 Positions and features of Segment 2 Positions and features of Seg2: ( 105.130/32.425_104.577/31.966) Segment 2 is from Chengjiaba to Gaochuan, about 50km long, it is complex and variable. The displacement is mainly in 4~6m, several points reaches 7~9m

13. Table 1 Description of positions and features of each rupture segments derived from pixel offset tracking Method unclear rupture trace 12 km south to Yingxiu-Beichuan fault, along Hanwang-Hongbai town-Bailu-Xiang’e, clear colored belt, 66km-long rupture along Guanxian-Jiangyou fault, with sense consistent to south wall of Yingxiu-Beichuan fault in north, no visible rupture trace Hanwang to Xiang’e Guanxian-Jiangyou 104.186/31.491 103.703/31.070 6 unclear rupture trace 27km long, featured by varied colors, no clear traces on seen, smaller displacement less than 1m Yingxiu to Dajinping West to Yingxiu 103.460/30.993 103.344/30.874 5 complex rupture 29.5km long, relief and curve, local deformation 3-5m west of Xiaoyudong, at Hongkou and Yingxiu, individually up to 6m, broader deformation in upper wall Xiaoyudong to Yingxiu Hongkou-Yingxiu 103.720/31.213 103.460/30.993 4 uniform rupture 61.5km long, straight, NE extending, broader deformation in upper wall up to 15~20km Gaochuan to Xiaoyudong Qingping-Jingtang 104.159/31.627 103.720/31.213 3 complex rupture 50km long, relief, big width (2~8km) and displacement, 4~6m depressions southwest of Chaping, Leigu and northeast of Beichuan, few reaching 7~9m Chengjiaba to Gaochuan Beichuan-Chaping 104.577/31.966 104.159/31.627 2 Uniform rupture 75km long, straight, narrow, bigger amplitude in north wall, broad and weak deformation in south wall Suhe to Chengjiaba Pingtong-Nanba 105.130/32.425 104.577/31.966 1 Note Features of rupture traces location Name and positions No.

16. This Fig shows displacement profiles in Beichuan and Dujiangyan respectively across the YBF, it indicates the largest displacements for the entire rupture zone is about 6m in up side and 2m in down side of the seismic fault (a) East of Beichuan. (b) North of Dujiangyan Displacement profiles -2 0 2 4 6 8 1 10 20 30 40 Distance/km displacement/m -4 -2 0 2 4 6 8 1 10 20 30 40 Distance/km displacement/m

18. Thank you very much!