Thrust fault is the basic model of crustal deformation and also one of the major structural forms of orogenic belts, indicating the tectonic environment of compression. Most of the catastrophic earthquakes that affect human activity occur within the plates. In the interior of the plate, reverse faults are likely to develop as long as there is compressive stress in the regional sense or under some local tectonic conditions. It is considered that the NS compression resulting from collision of the Indian plate and the Eurasian plate is the main cause for the formation of the present tectonic framework in both north and south sides of Tianshan Mountains. The continuous crustal shortening and thickening has made the Quaternary active structures in the front margins of Tianshan Mountains well developed. Meanwhile, the new nappe structures in front of Tianshan Mountains are also the main sites for the preparation of medium-strong earthquakes in the Tianshan Mountains area, and their seismogenic mode is mostly in the forms of blind fault ramp-decollement plane-surface fault ramps.
The northern Tianshan inverse fault-fold belt is located at the junction between the northern foothill of Tianshan Mountains and Junggar Basin, where the Kusongmuqike piedmont fault is located in the south of Jinghe County, and is an important active thrust fault belt in the western northern Tianshan Mountains. In recent ten years, there were many earthquakes with magnitude 5.0 or above occurring in the eastern section of the fault zone. A detailed study of the geometric distribution and tectonic geomorphologic features is helpful to understand the tectonic deformation characteristics and regional strain distribution in the Tianshan area since the late Quaternary. The results of high-resolution remote sensing image interpretation, UAV aerial survey and differential GPS terrain profile survey combined with field geological survey show that the eastern segment of the Kusongmuqike piedmont fault is composed of two secondary reverse faults. Among them, the south branch, the Xinlongkou Fault, is composed of 5 en echelon-arranged sub-faults, with an overall trend of NW, dipping S, steep dip angle, and a length of about 48km. The fault offset the two-stage piedmont alluvial-pluvial fan and 5 river terraces, the activity time of terrace T1/T2 and fan3 is the latest, and the fault scarps are 3.6m to 4.7m high, being the product of concurrent fault activities. The vertical displacement of terrace T3 and T4 is 13.5m and 20.3m, respectively, and the vertical displacement of terrace T5 is roughly the same with that of the surrounding pluvial fan2, which is about 30m. On the fan1, there is no tectonic deformation observed in places where the fault passes through, and the initial landforms are retained on the surface. The north branch, the Hydrographic Station Fault, is distributed in an intermittent manner. The overall strike of the fault is near EW, with a total length of about 44km, and the fault offset multi-stage alluvial-pluvial fans. On the alluvial-pluvial fan of Fan3, two near-parallel normal scarps are developed in the northern margin of the alluvial-pluvial fan, while other faults cut through the alluvial-pluvial fan and the surface gully, forming steep reverse scarps on the surface. According to the cumulative height of the normal scarps, the maximum vertical displacement is 17.2m and the minimum vertical displacement is 0.3m, the scarp height is concentrated between 4.7~9.9m. On the reverse fault scarps, the maximum vertical displacement is 7.8~9.8m, the minimum scarp height is 2.4~3.1m, and the scarp height concentrates between 3.3~9.2m. Several sub-faults are developed scatteredly between the two sets of faults, with scarp heights ranging 0.5~1.0m. As far as the scarp height distribution is concerned, its vertical displacement shows a distribution law of decreasing from west to east. These results may contribute to the further understanding of the strain partitioning pattern in the western part of the northern Tianshan.

There were several strong earthquakes of M_S≥7.0 occurring in the eastern Tianshan in the history, which is an important part of Tianshan earthquake zone. The Tangbal-Tasdun Fault is a left-lateral strike-slip fault zone of Late Pleistocene in the northwest of Barkol Basin. The study of the characteristics of its late Quaternary activities is one of the important basic work to understand the risk of strong earthquakes in Barkol area. Due to the low level of research in the eastern Tianshan region, there is a lot of controversy over the historical earthquakes. But there is no doubt that this area has the ability of generating earthquakes of magnitude greater than 7.0. Current GPS monitoring data on both sides and inside of Tianshan Mountains shows an about 20mm/a northward movement of the Pamir and Tarim plates, but a 4mm/a crustal movement rate of eastern Tianshan. This indicates that the tectonic activity of the western section of Tianshan Mountains is obviously stronger than that of the eastern section. However, according to the historical earthquake records of eastern Tianshan, there are at least two earthquakes of magnitude 7 or above happening in Barkol region. This indicates that the tectonic activity in the Barcol area is intense and the area has the condition for generating strong earthquakes.
In this paper, the methods of high resolution satellite image interpretation, field observation and analysis, micro-geographic survey and trenching are used. The geometric distribution characteristics of the Tangbal-Tasdun Fault are determined, which reveals the movement and activity of the fault zone. The activity parameters of the fault since late Pleistocene are preliminarily obtained. The results show that the fault is left-handed strike-slip with thrust motion. A surface rupture zone with a length of about 50km is developed in the east of Jijitaizi Village. The fault offset the T2 terrace with a vertical displacement of about 0.9m and a horizontal displacement between 9m and 11m. The vertical displacement of T3 terrace is about 1.6m, and the horizontal displacement is between 13m and 20m. To the west of Hongjingzi Town and Tashbastawu Village, the fault is distributed in a straight line on satellite images. The fault offset the latest geomorphic surface, with the minimum vertical displacement of about 0.1m, the maximum vertical displacement of 2m, and the horizontal displacement of 1.8~4.3m. The horizontal displacement of the fault is larger than the vertical displacement of the same period. The excavation of a trench near Kutaizi village shows that the fault has obvious characteristics of strike-slip movement. According to the phenomena of water spraying and sand emitting along the fault and the relation of cut and cover between the fault and strata, two ancient seismic events are revealed in the trench. The most recent event ruptured the ground surface. According to the empirical formula for magnitude estimation, M=7.13+0.68lgD, it is calculated and inferred that this fault section is qualified for the occurrence of M7.3~7.4 earthquake.

The Pishan M_S6.5 earthquake occurred in the west Kunlun piedmont area. According to the surface deformation data obtained by the Pishan M_S6.5 earthquake emergency field investigation team, combined with the positioning accuracy of spatial distribution of aftershocks information, the focal mechanism solutions and deep oil profile data, we think the Pishan M_S6.5 earthquake is a typical thrust faulting event, and the seismogenic structure is the Pishan reverse fault-anticline, which did not produced obvious surface fault zone on the surface. In the vicinity of the core of the Pishan anticline, we found some tensional ground fissures whose strikes are all basically consistent with the anticline. We propose that the surface deformation is caused by the folding and uplift of the anticline. The Pishan earthquake is a typical folding earthquake. The tectonic deformation of the west Kunlun piedmont is dominated by the thickening and shortening of the upper crust which is the typical thin-skinned nappe tectonic. The Pishan earthquake occurred in the frontal tectonic belt, the root fault of the nappe structure has not been broken, and we should pay attention to the seismic risk of the Tekilik Fault.