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Knowledge of the slip behavior of the Altyn Tagh fault (ATF) has significant implications for our understanding of the tectonic deformation of the Tibetan Plateau. In this study, we process Global Positioning System (GPS) data spanning 2009–2017 across the western ATF, merge the solution with recently published GPS velocities, and obtain a dense GPS velocity field for northern Tibet. We introduce an elastic block model and estimate the fault slip rate, interseismic fault coupling (ISC), and seismic moment accumulation rate along the ATF. The estimated left‐lateral strike‐slip rate of the ATF decreases eastward from 12.8 ± 0.4 mm/a to 0.1 ± 0.2 mm/a. Results show a heterogeneous distribution of ISC along the fault, with the fault locking depth varying from 5 to 20 km. The seismic moment accumulation rate is 2.16–2.37 × 1018 N m/km along three segments between Sulamu Tagh and Aksay bends, where the accumulated seismic moment over the last five centuries could be balanced by earthquakes with magnitudes of Mw 7.7, Mw 7.6, and Mw 7.8, respectively. We calculate the ratio of the Indo‐Eurasia convergence accommodated by the ATF and find that 10.3% of the convergence is accommodated along the fault by lateral extrusion; quantitative analysis of the strain rate, however, shows that a large part of the northern Tibet is not well described by elastic block rotation. Consequently, we suggest that a hybrid kinematic model that includes both block‐like and continuous deformation is needed to better delineate the crustal deformation of the Tibetan Plateau. Key Points: Altyn Tagh fault slip rate and coupling inverted using new, dense interseismic GPS velocitiesThe three fault segments between Sulamu Tagh and Aksay bends have the potential to rupture in Mw 7.7, Mw 7.6, and Mw 7.8 earthquakesA hybrid kinematic model is needed to delineate the crustal deformation of the Tibetan Plateau [ABSTRACT FROM AUTHOR]

Based on the dense GPS velocity field in the northeastern margin of the Tibetan Plateau from 1999 to 2016, we have produced the deformation and strain characteristics of the Haiyuan fault and the Liupanshan fault. Estimated long-term slip rate along the Haiyuan-Liupanshan fault zones show a gradual decrease from 6.4 ± 1.6 mm/yr at the Tuolaishan fault to 2.9 ± 1.2 mm/yr at the Southern Liupanshan fault. Left-lateral thrusting movement was inverted for the Xiangshan-Tianjingshan fault (XS-TJS), which has an average slip rate of 2.1 ± 3.4 mm/yr during the study period. We also calculated the heterogeneous distribution of interseismic coupling along the fault zones. Our result also shows the locking depth of the Tianzhu seismic gap is ∼22 km. The slip rate deficit, the seismic moment accumulation rate, and the Coulomb stress accumulation rate are high on the fault planes, whereas the second invariant of the strain rate is low at the surface. The Liupanshan fault is locked to a depth of ∼23 km, and the corresponding seismic moment accumulation rate on the fault plane is high, while the strain rate at the surface is low. The accumulated strain along the Tianzhu seismic gap and the Liupanshan fault could be balanced by earthquakes with magnitudes of Mw7.9 and Mw7.4, considering the absence of large earthquakes over the last 1000 years and 1400 years respectively. The Haiyuan segments had ruptured during 1920 Haiyuan earthquake, and the estimated locking depth for period 1999–2016 is 5–10 km. Its seismic moment accumulation rate at depth is low and the strain rate at the surface is high. Our result indicates that 70% of the strike-slip along the Haiyuan segments transforms into thrusting along the Liupanshan fault, while the remaining 30% is related to the orogeny of the Liupanshan. For slip between the Haiyuan fault and the XS-TJS, about 27–34% of the slip is partitioned on the XS-TJS. [ABSTRACT FROM AUTHOR]

GPS-derived horizontal velocities, geologic fault slip rates and earthquake-derived fault slip vector azimuths are inverted simultaneously for fault coupling and slip rate deficit on the Haiyuan-Liupanshan fault in the northeastern margin of the Tibetan Plateau. Along the Haiyuan fault, the results show 3.2–6.2 mm/yr of left-lateral strike-slip, and the strike-slip transformed into thrusting deformation (2.8–3.5 mm/yr) along the Liupanshan fault. The results suggest full coupling down to ∼10 km along the Haiyuan fault. Significant portions from the Jinqianghe fault to the Maomaoshan fault, however, are locked to ∼23 km depth. The abrupt change in fault coupling coincides with the Tianzhu seismic gap. High slip rate deficit (3.0–4.5 mm/yr) and seismic moment accumulation rate are also interpreted along the seismic gap. The Liupanshan fault is locked to 15–20 km depth. A high seismic moment accumulation rate, low slip rate deficit (2.0–3.2 mm/yr) and scarcity of large seismic event over the last 1400 years may imply high strain accumulation on the fault. The results demonstrate that crustal deformation in the northeastern Tibetan Plateau is dominated by elastic block rotation. We also conclude that deformation due to fault coupling is limited along the near-field (less than 50 km with velocities less than 2 mm/yr) of the Haiyuan-Liupanshan fault. [ABSTRACT FROM AUTHOR]

The spatial pattern and rate of strain accumulation on a fault during the pre- and inter-seismic phases are very important for interpreting the mechanism of earthquakes and evaluating seismic potentials. Here we use global positioning system (GPS) data and the block-dislocation model to invert for the locking degree and slip rate deficit of the Main Himalayan Thrust (MHT) fault in the southern margin of Tibet before the 2015 M w 7.9 Nepal earthquake. Results show that the locking depth and slip rate deficit increase from the west to the east. Along the western segment of the MHT fault (80°E–84°E), the locking depth is estimated to be 12–17 km with a slip rate deficit of 0–5 mm/a; along the central Nepal segment (84°E–87°E), the locking depth is 16–21 km with a slip rate deficit of 6–10 mm/a, whilst along the eastern segment (87°E–90°E), the locking depth increases to 23–26 km with a slip rate deficit of 8–13 mm/a. The 2015 Nepal earthquake initiated at the boundary between the western and central segments, an area with as where the slip rate deficit varies dramatically from 0 to 9 mm/a within 50 km resulting in high energy gradients. High strain concentration along the central and eastern segments leads to unilateral propagation of the rupture to the east. Given the paucity of large seismic events over the previous decades and the current high slip rate deficit, seismic hazard on the eastern Nepal segment remains high. [ABSTRACT FROM AUTHOR]

On 17 November 2017, a Mw 6.5 earthquake occurred in Mainling County, Nyingchi City, China. The epicenter was located in the Namche Barwa region of the eastern Himalayan syntaxis. Here, we have derived coseismic deformation from Global Positioning System (GPS) data and ascending Sentinel-1A Synthetic Aperture Radar (SAR) data. Based on a joint inversion of the two datasets, we obtained the coseismic slip distribution along a curved, northeast trending, and high-angle (dip angle of 75°) thrust fault. Our results show that the seismic moment release was 7.49 × 1018 N∙m, corresponding to a moment magnitude of Mw 6.55. The maximum slip was 1.03 m and the main rupture zone extended to a 12 km depth. The earthquake may have been related to the release of strain accumulated during the subduction of the Indian plate beneath the Eurasian continent. We identified a high strain rate and low b-values around the epicentral area before the earthquake, indicating that the earthquake was nucleated under a high strain/stress state. The data indicate two regions, southwest and southeast to the epicenter (the eastern Main Himalaya Thrust and northern end of the Sagaing fault), which remain under high stress/strain conditions and pose a significant seismic hazard. [ABSTRACT FROM AUTHOR]