The Ganzi-Yushu Fault, the boundary of Bayan Har active tectonic block, Qiantang active tectonic block and Sichuan-Yunan active tectonic block, is a sinistral strike-slip fault zone with intensive Holocene activity. Thus, the study of activity characteristics and rupture behavior of paleoearthquakes in the late Quaternary on the Ganzi-Yushu Fault is of fundamental importance for understanding the future seismic risk of this fault. The southeast section of Ganzi-Yushu Fault is made up of three segments of Ganzi, Manigange and Dengke, where a M_S7.3 earthquake in 1866, a M_S7.7 earthquake in 1854 and a M_S7.3 in 1896 occurred, respectively. There is still lack of in-depth study on the active features and the cascading rupture possibility of these segments, which hindered the evaluation of seismic risk for the southeast section of Ganzi-Yushu Fault. By the means of field geological survey and micro topography measurement, this paper studied the geological and geomorphological features of the southeast section of the Ganzi-Yushu Fault. The results show that the Ganzi and Dengke segments show obvious extension movement, in addition to the left-lateral movement. For Manigange segment, the characteristics of the movement are mainly left-lateral strike-slip and thrusting, and the maximum vertical displacement of the Holocene strata is greater than 2m. In part areas, the movement is normal faulting, which perhaps relates to the left stepping zone in the local stress environment. Therefore, combining the research results such as the fracture distribution in different motion characteristics, rupture behavior of paleoearthquakes, and the distribution of historical earthquake surface ruptures, we divide the southeast section of Ganzi Yushu Fault into Ganzi, Manigange and Dengke segment, and consider the Yakou and the Dengke Basin as the stepovers and the segments' boundaries. As the small scale of impermanent barriers including Dengke Basin and the ridge near Yakou, of which the width is about 1~2km, they may be broken through in great earthquake rupture in future. A trench was excavated in Zhuqing township to investigate the paleoearthquakes on the Manigange segment, radiocarbon dating was employed and 3 paleoseismic events were revealed in the Zhuqing trench, which are the seismic events occurring respectively at 3875~3455BC, after 775BC, and the latest one that ruptured the surface. Compared with the previous results of paleoseismology in the southeast section of Ganzi-Yushu Fault, it is found that the paleoseismic events in the Manigange segment are obviously different with that in Ganzi segment and Dengke segment. Due to the lack of sufficient data on the southeast section of the Ganzi-Yushu Fault, it still needs further discussion whether the cascade-rupturing between these segments exists.

This study focuses on four moderate-sized earthquakes in the northern margin of the Qaidam Basin, northeastern Tibet Plateau, China, of which one occurred in 2008, and three in 2009, respectively. We obtain coseismic displacement fields of these four events using Envisat descending ASAR data and D-InSAR technology. The results show that the 2008 earthquake has only one deformation center and the 2009 earthquakes have three deformation centers in their fields. The maximum displacement of 2008 and 2009 earthquakes are 0.097m and 0.41m in the LOS(line of sight), respectively. We invert ground displacements of these earthquakes based on elastic dislocation models to estimate slip distribution on fault planes. For the 2008 event, using a one-segment fault model, the inversion reveals peak slip of about 0.47m occurring at a depth of 19km. For the 2009 earthquakes, the ground displacement pattern observed by InSAR can be fitted by a three-segment fault model with smallest RMS of residuals. The three sectional fault model is considered the most reliable.

Consisting of three water diversion projects, i.e. Western Route Project(WRP), Middle Route Project(MRP)and Eastern Route Project(ERP), South-to-North Water Diversion Project is by far the world's largest water conservancy project. It is also a major strategic infrastructure to optimize the allocation of water resources in China.
The MRP has a total length of 1267km, including a canal segment of 731km long located in Henan Province, which accounts for more than half of the total mileage and runs through from north to south the central plains of China. The project starts mainly in the north of Henan Province, running through Hebi mining area(i.e. Hebi Coal Industry Group Co. Ltd.), Tangyin graben, three cities(i.e. Weihui, Hebi and Anyang city)and two counties(i.e. Qixian county and Tangyin county). Being threatened by mining subsidence, regional tectonic activities and urban groundwater subsidence, its embankment is prone to instability.
In order to assess the stability of embankment along the route, and also to provide safety guarantee for the water diversion project, with the case of the north Henan section of Middle Route Project(MRP), all 9 periods of ENVISAT ASAR data of 2009 are processed by means of 2 PASS plus external DEM D-InSAR processing algorithm, the parameters of space-time baseline are analyzed, best optimal interferometry images pairs are selected, and D-InSAR processing strategies are optimized to obtain differential interferograms for 33 monitoring points along 127km route; information of subsidence area, urban surface settlement area, as well as the amplitudes due to groundwater mining is extracted, and thematic maps of interferometric phase change vectors are gotten.
The following understandings are obtained: 1)There is uneven subsidence over the diversion canal. The cumulative minimum amount of subsidence is -33mm, and maximum subsidence is -73mm in 350 days. Annual subsidence rate is between 0.34m/yr to 0.76m/yr, and annual average subsidence rate is 0.53m/yr. In general, subsidence of monitoring points fits with exponential distribution, with the average correlation coefficient R²=0.7418. According to some mathematical models of curve fitting for monitoring point subsidence, it can be predicted that the subsidence of embankment of water diversion canal tends to be stable in majority of the sections. At the same time, both subsidence value and rate are getting smaller. 2)This study shows that due to combined effect from a variety of factors, this region has a poor regional geological stability. Analysis reveals that tectonic activity and urban surface subsidence are the main influencing factors, infrastructure construction is the secondary effect on the embankment stability, and there is no direct correlation with mining subsidence.

Differential Synthetic Aperture Radar Interferometry (D-InSAR) is a newly developed technique for monitoring large-scale ground deformation with some prominent advantages such as high accuracy and pantoscopic view. The vertical crustal deformation accuracy can be measured by D-InSAR technology to the millimeter level, but due to restrictions of spatial, temporal decorrelation and atmospheric delay, the application to the monitoring of the crust long-term slow deformation is limited. The Permanent Scatterers approach, which is based on conventional InSAR technique, puts emphasis on processing time series of SAR interferograms by recognizing and analyzing single scatterers with a stable backscatter intensity or reliable phase behavior in time, to study the deformation histories of the earth's surface in a long time series. The PS approach can better conquer problems of temporal and spatial decorrelation, also the atmospheric delay effect, which will improve the efficiency of datum utilization when measuring large time scale deformation events. The PS-InSAR, as an innovation of D-InSAR technology, can overcome the loss of coherence time, and meanwhile, calculate and eliminate the atmospheric effects to ensure the normal operation of the interferometric processing. It acquires the accumulated deformation and its rates at the coherent points in the images.
In this paper, the basic principle, advantage and status of PS-InSAR are introduced. The slight deformation of Gangu area in the fault zone along the north fringe of west Qinling Mountains which is one of the major left-lateral strike-slip active faults in northeastern margin of Tibetan plateau is monitored by PS-InSAR technology using 14 scenes of ENVISAT ASAR data from May 2008 to September 2010. The result shows that the rate of the north wall of the fault zone is -1～-2mm/a, the rate of the south wall of the fault is 3～4mm/a, and relative slip rate between the two walls of the fault zone in Gangu area along the north fringe of west Qinling Mountains is approximately 5mm/a; the points target deformation rate and deformation direction both match with the left-lateral motion feature of the north fringe fault zone of west Qinling Mountains, and results have a good agreement with the study results by other scholars. This suggests that the PS-InSAR technology is capable of detecting crustal small deformation.

On November 14,2001,an M_s 8.1 earthquake occurred in the west of Kunlunshan Pass. This event is the greatest earthquake that occurred in China continent following the Zayu-Medog,Xizang M_s8.6 earthquake of August 15,1950 and the Damxung,Xizang M_s 8.0 earthquake of November 18,1951. The earthquake occurred in Hoh Xil,a depopulated zone in the northern Qinghai-Xizang Plateau,where field investigation is very difficult to be carried out due to harsh climate and thin air. High spatial resolution satellite images are applicable to the interpretation of earthquake surface rupture zone. The 10m spatial resolution SPOT images may reveal distinctly the major rupture zone,while the 1m spatial resolution IKONOS images may display the fine structures and kinematical characteristics of the surface rupture. This paper presents the results of the study on the surface rupture of the west of Kunlunshan Pass earthquake by using SPOT and IKONOS images. The study shows that the surface rupture zone is located mainly along the abrupt variation zone of landforms on the alluvial-pluvial platform or the rear edge of the platform at the southern foot of the Kunlunshan Mountains. The surface rupture to the east of Buka Daban Peak is about 350km in length and striking 100°,consisting of 3 sub-rupture zones. This surface rupture is superimposed on the preexisting rupture zone. A series of gullies crossing the rupture zone have been offset left-laterally,and the average slip rate is estimated to be 13.4～16.8mm/a. The interpretation of the SPOT and IKONOS images demonstrate that the macroscopic epicenter of this earthquake should be at 93°17′E,35°47′N,in the vicinity of the Yuxifeng Peak,where the maximum left-lateral horizontal dislocation is 7.8m and the width of the surface rupture zone reaches up to 1250m. This conclusion is in good agreement with the location of macroscopic epicenter (93.3°E,35.8°N ) deduced by China Earthquake Administration for this earthquake.