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High‐resolution topographic data sets have now become increasingly available, which allows for remotely measuring and analyzing offset features and their associated slip distributions at a very high resolution along a fault, hence providing important insights into the fault behavior. The West Helanshan Fault is a Holocene active right‐lateral strike‐slip fault located at the junction of the Tibetan Plateau, Alashan, and Ordos blocks. In this study, a 2‐m‐resolution DEM of the West Helanshan Fault was built from the WorldView‐3 stereo satellite images (0.5 m). Combined with the high‐resolution topography acquired from the Unmanned Aerial Vehicle (UAV) images based on the Structure from Motion (SfM) method, a total of 180 lateral offsets and 201 vertical displacements were acquired along ~50 km of the fault. By statistical analysis of the offset observations and constructing the cumulative slip profiles, we conclude that large paleoearthquakes have produced characteristic slip accumulation along the fault with a right‐lateral slip of ~3 m and a vertical slip of ~1 m, rupturing at least two segments of the fault simultaneously, which corresponds to a moment magnitude of Mw 7.1 ~ 7.5. The cumulative slip profiles suggest that the fault has likely propagated northward over its lifetime, and the south segment may be the most mature section of the fault where larger coseismic slip of earthquake ruptures may occur. The ratio of lateral to vertical displacement has remained constant (~3:1) through multiple successive events, indicating that the fault has maintained the same kinematic style over the last few thousands of years. Key Points: Large paleoearthquakes have produced characteristic slip along the fault with a lateral slip of ~3 m and a vertical slip of ~1 mThe fault has propagated northward over its lifetime, and larger coseismic slip of earthquakes may occur on the south segment of the faultThe fault has maintained the same kinematic style with a constant ratio of lateral to vertical displacement [ABSTRACT FROM AUTHOR]

Abstract: Reconstruction of the along‐fault slip distribution provides an insight into the long‐term rupture patterns of a fault, thereby enabling more accurate assessment of its future behavior. The increasing wealth of high‐resolution topographic data, such as Light Detection and Ranging and photogrammetric digital elevation models, allows us to better constrain the slip distribution, thus greatly improving our understanding of fault behavior. The South Heli Shan Fault is a major active fault on the northeastern margin of the Tibetan Plateau. In this study, we built a 2 m resolution digital elevation model of the South Heli Shan Fault based on high‐resolution GeoEye‐1 stereo satellite imagery and then measured 302 vertical displacements along the fault, which increased the measurement density of previous field surveys by a factor of nearly 5. The cumulative displacements show an asymmetric distribution along the fault, comprising three major segments. An increasing trend from west to east indicates that the fault has likely propagated westward over its lifetime. The topographic relief of Heli Shan shows an asymmetry similar to the measured cumulative slip distribution, suggesting that the uplift of Heli Shan may result mainly from the long‐term activity of the South Heli Shan Fault. Furthermore, the cumulative displacements divide into discrete clusters along the fault, indicating that the fault has ruptured in several large earthquakes. By constraining the slip‐length distribution of each rupture, we found that the events do not support a characteristic recurrence model for the fault. [ABSTRACT FROM AUTHOR]

Abstract: Eastern Tibet is an important example of oblique convergence and associated strain partitioning, as suggested by recent 2‐D and 3‐D structural interpretations, yet the nature and evolution of oblique strain partitioning of this region remain poorly known. Here we use seismic reflection profiles, borehole data, and field investigations in the Longmen Shan piedmont to determine the subsurface structural architecture, and we observe several nearly N‐S striking thrusts and reactivation of NE striking preexisting faults. We interpret that this behavior is due to a regional principal compressional stress oriented in the E‐W direction, oblique to the NE striking Longmen Shan. Using the records of fault activity and related Late Pliocene and Quaternary foreland sediments and growth strata, as well as the coseismic rupture of the 2008 Mw 7.9 Wenchuan earthquake, we demonstrate that the Longmen Shan has experienced E‐W crustal shortening and oblique motion since ~5–2 Ma. We present two strain partitioning models arising from oblique thrusting in eastern Tibet and suggest that the eastward extrusion from Tibet is mainly accommodated on the strike‐slip Longriba fault and the dip‐slip Longmen Shan‐Min Shan fault zones. These results enhance our understanding of the tectonic relationship between the Songpan‐Ganzi terrane and the Sichuan basin and provide additional constraints for studies of the geodynamic response of eastern Tibet to the ongoing India‐Eurasia collision. [ABSTRACT FROM AUTHOR]

The northeastern Tibetan Plateau and its surroundings are a tectonically complex region resulting from the continuing collision of India with Eurasia. We studied the tectonic deformation of this region using a GPS block model, which was produced using the most recently published, dense, precise, and complete GPS velocities available combined with a detailed fault geometry. The comparison between our preferred model with numerous faults and a model with fewer faults demonstrates the need for inclusion of lesser active faults affords a closer examination of strain partitioning. The predicted senses of motion and slip rates of active faults in our preferred model are consistent with the geological estimates, supporting the assumption that the decadal GPS slip rates are representative of millennial‐scale geologic slip rates. The observed fault kinematics in the northeastern Tibetan Plateau and its surroundings can be interpreted as the consequence of relative motions between different blocks and block rotations. Key Points: The inclusion of secondary active faults in block modeling affords a closer examination of strain partitioningThe senses of motion and slip rates of active faults predicted by our model are generally in agreement with geologic observationsDeformation of North Eastern Tibet and its surroundings can be interpreted as the result of relative motions between blocks and block rotations [ABSTRACT FROM AUTHOR]

The Qilian Shan, located in the northeastern Tibet, is under strong tectonic activity and earthquake motion due to the propagation of the plateau. At the mountain front of the eastern Qilian Shan, the Tongziba River, in the southern Zhangye Basin, flows northward and successively cuts the Minle‐Damaying Fault and the Yonggu Anticline, two parallel structures within the Frontal Thrust system of the Qilian Shan. Here we present a detailed record of seven strath terraces of this river that documents the history of active deformation of the two structures. Based on the estimated crustal shortening distance from the deformed terraces and the terrace formation age constrained by AMS 14C and optically stimulated luminescence (OSL) dating, a horizontal slip rate of 1.4 ± 0.5 mm/year of the Minle‐Damaying Fault is constrained since 16.7 ± 1.8 kyr, and a shortening rate of 1.3 ± 0.4 mm/year across the Yonggu Anticline has been estimated in a similar time frame, respectively. In total, the shortening rate across the mountain front is estimated to be 2.7 ± 0.6 mm/year. GPS data show a similar modern shortening rate in this area, which indicates the rate of crustal shortening may be comparable in the modern and 104‐year scales. Our study supports a higher crustal shortening rate along the mountain front of the eastern Qilian Shan than that of the western Qilian Shan since the Late Quaternary. Key Points: The Minle‐Damaying Fault and the Yonggu Anticline have been active since at least 16.7 ± 1.8 kyrEstimated Late Quaternary shortening rate across the eastern Qilian Shan foreland is 2.7 ± 0.6 mm/year from terraces analysisCrustal shortening rate along the mountain front of the eastern Qilian Shan is probably higher than that of the western Qilian Shan [ABSTRACT FROM AUTHOR]

The Pamir Frontal Thrust along the leading edge of the northern Pamir is characterized by multiple earthquakes with moment magnitudes of 6.5–7.1. Geometric characteristics of the Pamir Frontal Thrust corresponding to these earthquakes and to future seismic hazards, however, remain largely unexplored. This study focuses on the easternmost segment of the Pamir Frontal Thrust, where the Mw 6.9 Wuqia earthquake occurred in 1985. Through interpretation of available two‐dimensional seismic reflection profiles and surface mapping data, we develop a three‐dimensional geometric model for the fault plane. Our results illustrate that, at depth, the fault plane is separated by a subhorizontal detachment horizon into upper and lower ramps, and both ramps are significantly segmented, along strike, by transfer faults or lateral ramps as well. Such along‐strike and downdip segmentation of the thrust sheet apparently plays a significant control on seismic rupture process of the Wuqia earthquake and can well explain why the region is characterized by moderate‐magnitude (Mw 6.5–7.1) events. Additionally, our study helps quantify key constraints on the Cenozoic deformation and evolution of the northeastern Pamir and, specifically, determines a total shortening of ≤43 km at the Pamir front: accommodating about 15% of the total indentation of the Pamir range into central Asia. Key Points: The PFT fault plane is significantly segmented both in the downdip direction and along strikeRupture of the 1985 Wuqia earthquake is likely encompassed within the upper ramp of the Tuomuluoan PFT fault segmentTotal shortening at the Pamir front is ≤43 km: significantly less than ~300‐km‐northward Cenozoic indentation of the Pamir [ABSTRACT FROM AUTHOR]

Deciphering the relationship between lateral growth of faults and along‐strike deformation (i.e., shortening and uplift) in the Earth's upper crust remains a challenge. Here we gain insight into the relation between these processes by studying the Kashi anticline, an asymmetric, doubly plunging thrust‐fault‐related fold located in the southwest Tian Shan, China. We use seismic interpretation and field observations, together with 2‐D trishear and excess area methods, to quantify the distribution of shortening along this structure. The shortening distribution along strike of the Kashi anticline is nonlinear and has a peaked, asymmetric, bell shape, with a maximum value of 5.9 ± 0.2 km. After comparing the 3‐D structural model of the Kashi anticline and our trishear models, we propose that lateral propagation‐to‐maximum shortening ratio, initiation fault length, and lateral propagation rate control the lateral fault propagation process and the fold terminations. Moreover, the 3‐D fault morphology and the ages of the growth strata suggest that the Kashi anticline experienced two stages of lateral growth with propagation rates of 60 km/Ma between 1.4 ± 0.2 Myr and 0.9 ± 0.3 Ma, and ~67 km/Myr from 0.9 ± 0.3 Ma to present. These observations highlight the relation between the evolution of lateral fault growth and the along‐strike shortening distribution, allowing us to use the latter (which we can measure) to infer the former (which we cannot). These novel insights from the Kashi anticline can be used to understand lateral growth of thrust and normal faults worldwide. Key Points: Structural interpretations reveal that the western segment of Kashi anticline is a trishear fault propagation fold, whereas the eastern segment is a detachment foldVariations of lateral fault growth produced along‐strike shortening distribution with a peaked, nonlinear bell shapeKashi anticline experienced two stages of lateral growth with propagation rates of 60 km/Myr between 1.4 ± 0.2 and 0.9 ± 0.3 Ma, and ~67 km/Myr from 0.9 ± 0.3 Ma to present [ABSTRACT FROM AUTHOR]