TY - JOUR
AU - Bingquan,, Li
AB - SUMMARY Numerous V-shaped conjugate strike-slip fault systems distributed between the Lhasa block and the Qiangtang block serve as some of the main structures accommodating the eastward motion of the Tibetan Plateau. The Beng Co-Dongqiao conjugate fault system is a representative section, and determining its tectonic environment is a fundamental issue for understanding the dynamic mechanism of the V-shaped conjugate strike-slip fault systems throughout central Tibet. In this paper, we investigate the deformation rates of the Beng Co-Dongqiao conjugate faults using 3 yr of SAR data from both ascending and descending tracks of Sentinel-1 satellites. Only interferograms with a long temporal baseline were used to increase the proportion of the deformation signals. The external atmospheric delay product and the InSAR stacking strategy were employed to reduce various errors in the large-spatial-coverage Sentinel-1 data. The InSAR results revealed that the fault-parallel deformation velocities along the eastern and western segments of the Beng Co fault are 5 ± 1 mm/yr and 2.5 ± 1 mm/yr, respectively. The second invariant of the horizontal strain rates shows that the accumulated strain is centered on the eastern segment of the Beng Co Fault and Gulu rift. The velocity and strain rate fields show that the Anduo-Peng Co faults may be paired with the Beng Co fault to form a new conjugate system and the tectonic transformation between the Beng Co fault and Gulu rift. These results can better explain the tectonic deformation environment of the Beng Co-Dongqiao conjugate fault system and provide insights on the crustal dynamics throughout the entire plateau interior. Satellite geodesy, Radar interferometry, Continental tectonics: strike slip and transform, Joint inversion, Seismic cycle 1 INTRODUCTION The interior and periphery of the Tibetan Plateau are some of the most important regions that regulate the north–south convergence resulting from the collision of the Indian and Eurasian plates (Fig. 1a, Meade 2007; Ryder et al. 2014). Due to the complexity of the tectonic environment and the limitations of the current geodetic observation network in this area, the deformation mechanism of internal faults throughout the Qinghai-Tibetan Plateau, especially several small faults in the secondary blocks, requires further investigation. For example, many V-shaped conjugate strike-slip fault systems distributed throughout central Tibet serve as some of the main structures accommodating the eastward motion of the Tibetan Plateau (Yin & Taylor 2011). Therefore, investigating the present-day deformation and kinematic characteristics of central Tibet is fundamental for clarifying the dynamic mechanism of the Qinghai-Tibetan Plateau (Taylor et al. 2003; Taylor & Yin 2009). Determining the kinematics of collisional environments requires the identification of individual faults and the quantification of their deformation rates (Taylor & Peltzer 2006). The present-day distribution of active structures in central Tibet is dominated by a mixed model comprising of strike-slip faults and normal faults (Taylor & Peltzer 2006; Zhang 2007; Taylor & Yin 2009). The interaction between blocks and faults cannot be interpreted simply as a few large and active strike-slip faults along blocks boundaries; more thorough investigations of the internal deformation of the blocks are also needed. Figure 1. Open in new tabDownload slide The geotectonic setting of the study area. (a) Conjugate strike-slip fault zone in the central Qinghai-Tibetan Plateau (Yin & Taylor 2011). (b) Study region of this paper. The red arrows represent horizontal GPS velocities from the Crustal Movement Observation Network of China (CMONOC), and the black arrows indicate the new densified observation network. The GPS results have been converted to be parallel to the Beng Co fault. The black dotted rectangles delineate the coverage of the Sentinel-1 SAR data used in this study. The red dots represent the historical earthquakes(Mw > 3.5) that occurred in the study area from 1970 to the present (USUS, https://earthquake.usgs.gov/earthquakes/map/) and the two big earthquakes in 1951 and 1952 (Han 1983). Figure 1. Open in new tabDownload slide The geotectonic setting of the study area. (a) Conjugate strike-slip fault zone in the central Qinghai-Tibetan Plateau (Yin & Taylor 2011). (b) Study region of this paper. The red arrows represent horizontal GPS velocities from the Crustal Movement Observation Network of China (CMONOC), and the black arrows indicate the new densified observation network. The GPS results have been converted to be parallel to the Beng Co fault. The black dotted rectangles delineate the coverage of the Sentinel-1 SAR data used in this study. The red dots represent the historical earthquakes(Mw > 3.5) that occurred in the study area from 1970 to the present (USUS, https://earthquake.usgs.gov/earthquakes/map/) and the two big earthquakes in 1951 and 1952 (Han 1983). Monitoring the present-day deformation of active faults using space observation techniques is of great significance for learning the mode of structural deformation, the regional seismic activity and the crustal dynamic characteristics. In this paper, we focus on the Beng Co-Dongqiao fault system, one of the most prominent features in central Tibet (blue dotted rectangle in Fig. 1a). The Beng Co fault is an active tectonic zone that exhibits strong seismicity (Wu & Deng 1989; Yin & Taylor 2011). Current crustal deformation observations in Tibet mainly originate from global positioning system (GPS) surveys (Gan et al. 2007; Zheng et al. 2017). However, the current GPS network available in Tibet is not sufficiently dense to map the strain distribution along key faults. Therefore, the sparsity of crustal deformation-associated velocity observations based on geodesy constitutes one of the major factors preventing our understanding of the plateau's tectonic movements. Interferometric synthetic aperture radar (InSAR) provides an independent method of measuring crustal deformation and can be used to calculate the accumulation of strain as a result of active tectonics. Currently, the interseismic velocity and strain in many earthquake-prone regions have been measured with InSAR, thereby avoiding the predominant reliance on incomplete seismicity records along major faults, such as the North Anatolian fault in eastern Turkey (Walters et al. 2011; Elliott et al. 2016; Hussain et al. 2018), the San Andreas fault in the western United States (Tong et al. 2013; Lindsey et al. 2014; Jolivet et al. 2015; Khoshmanesh & Shirzaei 2018) and the Altyn Tagh fault in the Qinghai-Tibetan Plateau (Elliott et al. 2008; Liu et al. 2018; Wang et al. 2019; Xu & Zhu 2019). At present, a considerable amount of research has focused on the spatial deformation distribution characteristics of conjugate strike-slip faults in central Tibet using InSAR technology. These studies mainly use ERS and/or ENVISAT data (Garthwaite et al. 2013; Ryder et al. 2014; Taylor et al. 2006; Wang et al. 2019). The spatial coverage of the stripmap SAR mode is relatively limited (e.g. 100 km for ENVISAR ASAR stripmap mode). In this study, we combined GPS data with Sentinel-1 SAR images obtained via terrain observation by progressive scan (TOPS) mode (with a width of 250 km) from ascending and descending tracks to extract the high-resolution velocity field covering the Beng Co-Dongqiao conjugate fault system. The wide-swath InSAR stacking technique was used to eliminate the effect of interferometric errors and to extract weak deformation signals from strong background noise along these active faults. Constrained by the InSAR deformation results, the velocity and strain rates between the Beng Co and Dongqiao faults and the regional tectonic mode of deformation were analysed, and the results can provide insights into a better understanding of the roles played by the internal fault zones in central Tibet in the accommodation of tectonic activity. 2 TECTONIC AND GEOLOGICAL SETTING Previous researchers have performed substantial investigations of the tectonic background and deformation distribution of active faults across the Qinghai-Tibetan Plateau (Tapponnier & Molnar 1976; Armijo et al. 1986, 1989; Yin et al. 1994; Blisniuk et al. 2001; Taylor & Yin 2009; Yin & Taylor 2011). Armijo et al. (1989) defined an echelon dextral fault system known as the Karakoram-Jiali fault zone (KJFZ), mainly comprising the Beng Co fault, Gyaring Co fault, Lamu Co fault and Awong Co fault from east to west and extends south of the Bangong-Nujiang suture zone, and suggested that this fault zone is the product of the eastward movement of the Qiangtang block relative to the Lhasa block. The dextral strike-slip faults of the KJFZ are paired with NE sinistral strike-slip faults, thus forming a series of conjugate strike-slip systems. As a result, the entire fault system in central Tibet can be roughly divided into two groups: NW dextral strike-slip faults and NE sinistral strike-slip faults (Taylor et al. 2003). These conjugate strike-slip systems in central Tibet play important roles in accommodating both the east-west extension and the north-south compression of the Tibetan Plateau (Taylor & Yin 2009). The Beng Co-Dongqiao fault zone is a representative section of conjugate strike-slip systems in central Tibet (Yin & Taylor 2011). The Beng Co fault is a dextral strike-slip fault with a history of strong earthquakes (Fig. 1b). In 1951 and 1952, two large earthquakes with magnitudes of 8.0 and 7.5 occurred along the Beng Co fault and the nearby Gulu rift, respectively (Wu & Deng 1989; Han 1983). At present, many studies have used the InSAR method to acquire spatial deformation information on the conjugate strike-slip faults in central Tibet, and they have found that the deformations are not evenly distributed in central Tibet and that the slip rates on all of the conjugate strike-slip faults are low. For example, the deformation field of the main active faults in the Tibetan Plateau have been obtained by Multi-Temporal InSAR technology (MT-InSAR), and the estimated slip rates of these faults are low, and the tectonic strain is considered to be more broadly distributed across the plateau interior (Garthwaite et al. 2013). Ryder et al. (2014) also used the InSAR method to estimate the right-lateral slip rate of the Beng Co fault, which is approximately 1–4 ± 1 mm yr–1, and they believed that the deformation of the fault is mainly caused by a post-seismic relaxation response to the two large earthquakes in 1951 and 1952. Lakes and marsh basins are widely distributed between the Beng Co fault and the Dongqiao fault. These basins have similar geomorphological and tectonic characteristics and intersect with the Beng Co fault or Dongqiao fault at nearly 90°. Although the nature of the movement along the faults between the Beng Co-Dongqiao conjugate fault system varies, certain connections may be of great significance for studying the dynamics of the central Tibetan Plateau. Thus, further studies on the deformation mode and the seismogenic mechanism of this conjugate fault system are required to completely clarify the relationship between the movements of the active faults and the regional deformation of the tectonic blocks. 3 INTERSEISMIC SLIP RATE MONITORING 3.1 GPS measurements GPS data from 13 stations of the Crustal Movement Observation Network of China (CMONC) (Zheng et al. 2017) and 9 newly campaign stations observed annually over the period 2013–2017 were used in this paper (Table S1). The new stations are located along both sides of the Beng Co fault, within 10–20 km of the fault trace. The new stations filled the gaps of the existing GPS network in this area, which is essential for capturing the interseismic slip of the Beng Co fault. The new added GPS velocities were transformed into the Eurasia-fixed frame via the method by Kreemer et al. (2014) and Zheng et al. (2017). To visually show the right-lateral strike-slip motion characteristics of the Beng Co faults, the combined horizontal GPS velocities were then projected to the fault-parallel direction (Fig. 1b). The GPS results show a clear dextral strike-slip motion of the Beng Co fault, whereas the deformation signal of the Dongqiao fault is not obvious. 3.2 InSAR processing method Fault activity results acquired based on space geodetic technology (e.g. InSAR and GPS) have become one of the main methods of measuring seismic deformation (Wang et al. 2009, 2019). The InSAR technique suffers from several limitations (e.g. nuisance atmospheric signal noises) in measuring microdeformation signals. Several InSAR processing algorithms and external auxiliary data are commonly used to reduce these uncertainties (Berardino et al. 2002; Biggs et al. 2007; Cavalié et al. 2007; Elliott et al. 2008, 2016; Yu et al. 2017, 2018). The Beng Co-Dongqiao fault system stretches nearly 200 km in the east-west direction. Therefore, we selected wide-swath SAR data, which cover a broader area and were beneficial to obtaining the overall deformation signal of active faults in the Beng Co-Dongqiao conjugate strike-slip fault zone. One ascending track (T41) and two descending tracks (T48 and T150) were used to cover the entire conjugate fault zone (Fig. 1b and Table S2). The ascending T41 data covered the entire conjugate zone. However, the two descending tracks (T48 and T150) needed to be joined. The interferograms were generated with a long temporal baseline constraint, which can maximize the proportion of the deformation signal that can be blurred by background noise (Cavalié et al. 2007). The selection criterion of the interferogram pairs was a temporal baseline constrained to between 300 and 800 d. In total, 328, 234 and 354 interferograms were generated for Tracks 41, 48 and 150, respectively (Figs S1–S3). Because the study area is in the central part of Tibet, where the air is rather dry and the vegetation coverage is low, C-band ERS data and interferograms with a 6-yr temporal baseline can still ensure good coherence (Taylor et al. 2006). Similarly, in this study, the interferograms over 3 yr can still maintain high coherence. To suppress the background noises, stacking method with atmospheric corrected interferograms (Biggs et al. 2007) was used to acquire information about the surface deformation of the Beng Co-Dongqiao conjugate fault zone, and it offers the potential to better determine the movement behaviours of active faults. 3.3 Atmospheric phase correction method Turbulent dynamics within the troposphere will induce an obvious atmospheric phase gradient, which mainly affects the measurement accuracy in large regions (Yu et al. 2017, 2018). The Sentinel-1 TOPS mode periodically adjusts the beam direction to obtain broader observation coverage; however, it is also more vulnerable to the atmospheric environment. The weak deformation signals of interest in the study region are easily intertwined with the atmospheric delay phase error because wide-swath SAR sensors can acquire more information related to atmospheric disturbances. Compared with stripmap mode SAR, more complex mathematical and atmospheric models need to be constructed, which necessitates higher requirements for subsequent high-precision deformation inversion algorithms. For the turbulent tropospheric delay errors (also called short-wavelength atmospheric delay errors) and terrain-correlated atmospheric phase delay (TCAD), the external atmospheric delay product from high-resolution the European Centre for Medium-Range Weather Forecasts (HRES-ECMWF) data (Yu et al. 2017, 2018) and the stacking method (Biggs et al. 2007) were used, and adequate interferograms ensures that most interferometric tropospheric delay errors can be corrected effectively (Zebker et al. 1997; Wright et al. 2004; Biggs et al. 2007; Wang et al. 2009, 2019 ). 3.4 Long-wavelength phase error corrected A few interferograms were influenced by the long-wavelength phase in this study. The first- or second-order phase slope in the interferogram can be considered as a long-wavelength signal, which may comprise tropospheric delay, orbit error and/or interseismic displacement signals. Therefore, when estimating a linear or quadratic phase ramp to fit the long-wavelength interferometric phases, both the long-wavelength phase error (orbit and atmospheric phase) and the interseismic displacement signal may be removed simultaneously (Tong et al. 2013). The long-wavelength phase errors were corrected in this paper by restructuring the long-wavelength deformation signals through a screw dislocation model and 22 GPS stations distributed around the Beng Co fault zone. Using the GPS velocities, the locking depth and slip rate along the Beng Co faults (12 km and 6 mm yr–1, respectively) were obtained by a screw dislocation model (Text. S1). We assumed that the long-wavelength deformation is caused mainly by the strike-slip motion along the Beng Co fault. The deformation of the Dongqiao fault zone is relatively small, whereas the Gulu rift is due to its relatively small spatial scope. Then, the ground deformation signals in the line-of-sight (LOS) direction of T150 can be simulated by the screw dislocation model. Fig. S4 presents a cumulative phase map of the deformation over 1 yr. The interseismic deformation phase of each interferogram from T150 can be calculated based on the time interval of each interferogram. We selected an interferogram example derived from track 150 between 20 January 2016 and 20 February 2018, and it was dominated by an evident long-wavelength phase signal that completely concealed the interseismic deformation signal (Fig. S5a). The corrected phase in Fig. S5(f) was dominated by the interseismic deformation signal and less affected by long-wavelength atmospheric errors. A comparison of Figs S5F and S5A shows that the interseismic deformation signals were all submerged in the original interferogram. The simulated interseismic deformation signal was not directly added to the final velocity result but rather subtracted from the original interferogram, and then a long wavelength ramp was simulated from the residual phase. The purpose of this method is to simulate the long wavelength signal more accurately and prevent overcorrection of the interseismic deformation signals. 4 INSAR RESULTS AND MODELLING 4.1 LOS Interseismic deformation maps After correcting the atmospheric phase delay for each interferogram, we implemented a stacking procedure to map the interseismic deformation velocity as shown in Fig. 2. Tracks 48 and 150 were processed separately (Figs S6 and S7), and the overlapping areas were selected to calculate the overall offset. Finally, the results were merged according to the offset. Obvious relative deformation signals exist on both sides of the Beng Co fault in both the ascending and descending tracks. The deformation rate map generated from the ascending track (Fig. 2a) shows that the earth's surface in the south of the Beng Co fault moves towards the satellite, whereas it moves away from the satellite in the descending track (Fig. 2b). Combining the characteristics of these two deformation rate fields, we can preliminarily infer that the Beng Co fault has an obvious characteristic of dextral strike-slip motion, which is consistent with its geological motion background (Armijo et al. 1989). More detailed analyses will be discussed in Section 4.2. The LOS deformation rate of the Beng Co fault is approximately 2–3 mm yr–1. The relative velocity of the western segment of the Beng Co fault is lower than that of the eastern segments. Ryder et al. (2014) also used the InSAR method to estimate the dextral slip rates along the Beng Co fault to be approximately 3 mm yr–1 in the LOS direction. The activity along the Dongqiao fault is relatively smaller, possibly due to the accommodation of parts of the strain by other fault systems. Figure 2. Open in new tabDownload slide InSAR LOS deformation rate maps. The red dotted polygons indicate the overlap area between the ascending and descending tracks. (a) Ascending track 41; and (b) descending tracks 150 and 48. Figure 2. Open in new tabDownload slide InSAR LOS deformation rate maps. The red dotted polygons indicate the overlap area between the ascending and descending tracks. (a) Ascending track 41; and (b) descending tracks 150 and 48. 4.2 Fault-parallel deformation rate InSAR techniques can only measure 1-D deformations in the LOS direction. The LOS deformation signal is inherently insensitive to the motion in the north–south direction. Although the azimuth offset tracking technique can be used to recover the full displacement vector, the interseismic deformation is too small to be measured using the pixel offset tracking technique (Jin & Funning 2017). Nevertheless, because the Beng Co-Dongqiao conjugate strike-slip fault system is oriented at 20–30° to the east–west direction, the deformation in the north–south direction is relatively small and can be neglected. Thus, the LOS deformation can be converted to the fault-parallel and vertical directions using two observations from the ascending and descending tracks (Figs 3 and S8; Text S2). Figure 3. Open in new tabDownload slide Fault-parallel deformation rates along the Beng Co fault and Dongqiao fault. The positive values indicate eastward movement along the faults. The black dotted rectangles represent the rift lakes. (a) Fault-parallel deformation rate map along the Beng Co fault (BCF). The red dotted rectangle represents two profiles across the fault segments. (b) Fault-parallel deformation rate map along the Dongqiao Fault (DQF). Figure 3. Open in new tabDownload slide Fault-parallel deformation rates along the Beng Co fault and Dongqiao fault. The positive values indicate eastward movement along the faults. The black dotted rectangles represent the rift lakes. (a) Fault-parallel deformation rate map along the Beng Co fault (BCF). The red dotted rectangle represents two profiles across the fault segments. (b) Fault-parallel deformation rate map along the Dongqiao Fault (DQF). Fig. 3 shows the fault-parallel deformation rate maps of the Beng Co and Dongqiao conjugate faults. The two maps were converted from the LOS deformation based on the corresponding orientations of the two faults and incident angles of the SAR images. After decomposing the LOS deformation, the deformation characteristics parallel to the Beng Co fault (Fig. 3a) are much clearer than that in the LOS deformation maps. The Beng Co fault was divided into two segments, namely, eastern and western segments (Fig. 3a). This segment scheme is based on the strike angles of Beng Co fault, which is similar to Garthwaite et al. (2013). One profile was selected for each fault segment (profiles A–A' and B–B' in Fig. 3a). The results from these two profiles are shown in Figs 4(a) and (b) and compared with the GPS results. The GPS and InSAR results show good consistency; the slip rate along the eastern segment reaches 5 ± 1 mm yr–1, and that along the western segment reaches 2.5 ± 1 mm yr–1. Our results are in good agreement with those reported in other studies. For example, Garthwaite et al. (2013) estimated the deformation rate along the Beng Co fault to be 1–4 ± 1 mm yr–1. Ryder et al. (2014) claimed that the peak-to-peak right-lateral rate across the Beng Co Fault can reach ∼7.7 mm yr–1. Figure 4. Open in new tabDownload slide Velocity profiles corresponding to the dotted rectangles in Fig. 5. The grey dots represent the InSAR result, and the red dots indicate the GPS velocities. The red lines represent the best-fitting curve derived using the screw dislocation model. The misfit, S and D values represent the root mean square (RMS) misfit between the observation and model, slip rate and locking depth, respectively. (a) Profile A–A’, (b) Profile B–B’ and (c) Profile C–C’. Figure 4. Open in new tabDownload slide Velocity profiles corresponding to the dotted rectangles in Fig. 5. The grey dots represent the InSAR result, and the red dots indicate the GPS velocities. The red lines represent the best-fitting curve derived using the screw dislocation model. The misfit, S and D values represent the root mean square (RMS) misfit between the observation and model, slip rate and locking depth, respectively. (a) Profile A–A’, (b) Profile B–B’ and (c) Profile C–C’. As a conjugate fault to the Beng Co fault, the Dongqiao fault shows no obvious deformation. After converting the LOS deformation map to the orientation of the Dongqiao fault, the overall deformation magnitude was smaller than that of the Beng Co fault (Fig. 3b). We chose a section with obviously different patterns on both sides of the fault for a profile analysis, and we obtained a sinistral slip rate of 1.5 ± 1 mm yr–1 (Fig. 4c). Garthwaite et al. (2013) inferred a slip rate of 1–2 ± 1 mm yr–1 along the Dongqiao fault, which is similar to our results. 4.3 Deformation rate along the rift lakes Evident horizontal deformation signals were observed near the Peng Co and Dong Co rift lakes between the Beng Co and Dongqiao faults (dotted rectangles in Fig. 3). According to the geological interpretation, those rifts were formed by the east-west extension, and the subsidence signals should occur around these lakes. However, the deformation signals of different tracks around the lakes in Fig. 2 have opposite signs, and subsidence signals are not obvious around the lakes in Fig. S8. These findings indicate that the signals are not dominated by the vertical deformation. Thus, we ignored those vertical signals and only considered horizontal deformation along the fault (strike-slip) and perpendicular to the fault (extension) (Text S2). The horizontal deformation rate maps are shown in Fig. 5. Fig. 5(a) presents the map of the extensional deformation rate map across the fault, and Fig. 5(b) shows the map of the sinistral deformation rate along the fault. We selected four profiles perpendicular to the inferred fault in each map, and the pixels within 2 km of each profile line were used to estimate the deformation rates (Fig. S9). Based on the results shown in Figs S9(a–d), we can infer that the extensional deformation rate around the rift lakes is approximately 3–4 mm yr–1. There were also some identifiable deformation signals in the strike-slip direction of 1–2 mm yr–1 (Figs S9E, G and H). The result is close to the conclusions from UAV topographic surveying and 14C dating, which suggested that the slip rate of the Dong Co fault during the latter half of the Holocene was 0.7 + 0.3/−0.2 mm yr–1 (Li et al. 2019), and geological data, which indicated that the long-term slip component of sinistral strike slip deformation zone is 1.4 ± 0.8 mm yr–1 (Wu et al. 2005). Figure 5. Open in new tabDownload slide Horizontal deformation rate maps central on the rift lakes between the Beng Co fault and Dongqiao fault. The black dotted lines indicate the profiles, and the red dotted line represents the inferred fault trace. (a) Map of the extensional deformation rate across the fault. (b) Map of the sinistral deformation rate along the fault. Figure 5. Open in new tabDownload slide Horizontal deformation rate maps central on the rift lakes between the Beng Co fault and Dongqiao fault. The black dotted lines indicate the profiles, and the red dotted line represents the inferred fault trace. (a) Map of the extensional deformation rate across the fault. (b) Map of the sinistral deformation rate along the fault. 4.4 Locking depth and slip rate To fit the InSAR observations, we used a simple screw dislocation model to simulate the best-fit values for the locking depth and slip rate (Text S1). The best-fitting results are shown in Fig. 6, and the optimum values of the slip rate and locking depth along the eastern segment of the Beng Co fault are 5.5 mm yr–1 and 11 km, respectively, while the optimal values for the western segment are 3.5 mm yr–1 and 7 km, respectively. For the Dongqiao fault, we obtained optimal solutions of 2.5 mm yr–1 and 5.5 km for the slip rate and locking depth, respectively. Based on these optimal parameters, we plotted the model curves along the profiles in Fig. 4. The curves and observations demonstrate good consistency. The locking depth of the Beng Co and Dongqiao conjugate fault system is in the range of 5.5–11 km, which is consistent with Jackson's conclusion of centroid depths at 6–12 km (Jackson et al. 2008). Many similar faults with shallower locking depths are spread across the Qinghai-Tibetan Plateau, such as the Lamu Co fault, which has a locking depth of 3–5.8 km (Taylor & Peltzer 2006), and the Xianshuihe fault, which has a locking depth of 4 km (Wang et al. 2009). Moreover, the depths of relocation earthquakes (2013–2015) in the central Tibetan Plateau were primarily in the range of 5–10 km, as evidenced from the 3-D seismic velocity and attenuation tomography results along the Bangong-Nujiang suture zone(Zhu et al. 2017; Zhou et al. 2019). The shallow locking depth in the central Tibet may be because the relatively weak materials in the upper crust can facilitate the development of conjugate strike-slip fault systems (Zhou et al. 2019). Figure 6. Open in new tabDownload slide Fault parameters of the two segments of the Beng Co fault and the Dongqiao fault using the parameter search method via the screw dislocation model. Red stars indicate the best-fit solutions. (a) Eastern segment, (b) western segment and (c) Dongqiao fault. Figure 6. Open in new tabDownload slide Fault parameters of the two segments of the Beng Co fault and the Dongqiao fault using the parameter search method via the screw dislocation model. Red stars indicate the best-fit solutions. (a) Eastern segment, (b) western segment and (c) Dongqiao fault. 4.5 Strain rates field To study the characteristics of strain accumulation in the Beng Co-Dongqiao fault system, we used the geodetic measurements to estimate the crustal strain rates. As shown in Section 4.4, vertical deformation was ignored, and horizontal deformation fields ware obtained by using the ascending and descending InSAR velocities. The DistMesh code was utilized to discretize the InSAR horizontal deformation fields into regular grids (Persson & Strang 2005). The discretized horizontal velocities were extracted from InSAR velocities by averaging points in each mesh. The strain rate was calculated using the method of Shen et al. (2015). The code calculates the horizontal strain rate through interpolation of horizontal velocities. We employed the Gaussian decay function and azimuth weighting function to determine the optimal distance-dependent weight and spatial density weight, respectively (Shen et al. 2015). The second invariant of the strain rates are presented in Fig. 7. Accumulated strain is strongly centred on the eastern segment of Beng Co Fault and Gulu rift. A strain rate up to 20–50 nano-strain yr–1 is found across this region, which suggests that large strike-slip faults may currently be accumulating a large amount of strain presently, and the Gulu rift is in a relatively active tensile state. For the west segment of the Beng Co Fault, the magnitude of the strain rate is smaller than the east segment. According to the map of the principal strain rates (Fig. 7), the Beng Co Fault is dominated by a strike-slip motion with a small compressive component. The principal strain rate in the Gulu rift region is in a state of obvious tension, which is consistent with the formative environment characteristics of the rift. Figure 7. Open in new tabDownload slide Second invariant of the horizontal strain rates. The red lines represent the Beng Co Fault and Dongqiao Fault. The black arrow pairs are the principal strain rates. The green dotted rectangle indicates the region of the Anduo-Peng Co fault system. Figure 7. Open in new tabDownload slide Second invariant of the horizontal strain rates. The red lines represent the Beng Co Fault and Dongqiao Fault. The black arrow pairs are the principal strain rates. The green dotted rectangle indicates the region of the Anduo-Peng Co fault system. 5 DISCUSSIONS 5.1 Evidence for a new conjugate fault system The development of lakes of a certain scale on the Tibetan Plateau is often closely related to the activity of strike-slip faults and normal faults, such as Beng Co Lake (Fig. S10). A large number of grabens and rift lakes are distributed from Anduo County to Peng Co Lake (e.g. Co Na, Dong Co and Peng Co Lakes) (Armijo et al. 1989; Wu et al. 2005; Taylor et al. 2006; Yin & Taylor 2011; Li et al. 2019; Teng et al. 2019). There are some obvious signals of east-west movement accompanied by some sinistral strike-slip motion components in the north–south direction (Fig. 5). In addition, the focal mechanism of major historical earthquakes in the Anduo-Peng Co fault system is mainly dominated by the lateral strike slip (Fig. S11). Thus, we infer that the Anduo-Peng Co graben system may absorb part of the sinistral strike-slip component and forms a conjugate strike-slip system pairing with the Beng Co fault (Fig. 8), which is consistent with the inference of Wu et al. (2005). The Anduo-Peng Co fault system, which has a right-order oblique distribution spanning a length of 120 km, is controlled by normal faults and a small amount of left-lateral slip components, which may explain the distinct horizontal deformation signals of 1–2 mm yr–1 in the LOS deformation rate map along Peng Co Lake and Dong Co Lake (Fig. 3). There are differences in the strike angles between the eastern and western segments of the Beng Co fault. The strain rate of the western segment of the Beng Co fault is relatively small, and the conjugate system formed by the Beng Co fault and the Dongqiao fault is relatively stable. Meanwhile, the strain rate of the eastern segment is relatively large (Fig. 8); therefore, the new conjugate system comprising of the Beng Co fault and the Anduo-Peng Co faults system may be in constant stress adjustment. Figure 8. Open in new tabDownload slide Sketch map of the conjugate relationship among the main fault zones. The red dots represent relocated earthquakes from 2013 to 2015 (Zhou et al. 2019), and the rectangles indicate the conjugate fault zone. Figure 8. Open in new tabDownload slide Sketch map of the conjugate relationship among the main fault zones. The red dots represent relocated earthquakes from 2013 to 2015 (Zhou et al. 2019), and the rectangles indicate the conjugate fault zone. Compared with the graben system in southern Tibet, the graben scale Anduo-Peng Co faults system is clearly smaller despite its larger distribution density compared with that in southern Tibet (Teng et al. 2019). The Anduo-Peng Co fault system may be a new structural zone and less mature than the other fault zones, such as the Beng Co fault. Thus, the linear geomorphological characteristics are not as obvious as those of the other fault zones. The distribution of recent earthquakes between 2013 and 2015 suggests that earthquakes occurred mainly around the rifts and the two main conjugated fault zones (Fig. 8). Therefore, these rifts are under an active period of fault movement. 5.2 Tectonic transformation between the Beng Co fault and Gulu rift The deformation velocities across the Gulu rift parallel to the Beng Co fault are 5–6 mm yr–1 (Fig. 3), and the vertical velocities are approximately 2 mm yr–1 (Fig. S8). Chen et al. (2004) calculated the average extension rate in the Gulu rift to be 6.6 ± 2.2 mm yr–1 using fine model partitioning and GPS data. Fig. 3 shows that the eastern part of the Gulu rift is clearly connected to the northern side of the Beng Co fault. The strike-slip rate of the Beng Co fault is consistent with the extensional rate of the Gulu fault. In addition, the large extensional strain rate is presented at the end of the eastward extension of the Beng Co fault (Fig. 7), and the maximum extensional rate increases to 50 nano-strain yr–1. Thus, we infer that the right strike slip movement of the Beng Co fault has undergone tectonic transformation at the end of eastern segment, that is the pull-apart at the end of the Beng Co fault, which may have controlled the current extensional deformation of Gulu rift. At the southeastern end of the Beng Co fault, the dextral strike-slip may be absorbed by the Gulu rift while the extensional movement along the normal fault may gradually diffuse across the Gulu the rift area. According to the direction of the maximum extension axis of the principal strain rate shown in Fig. 7, the east margin fault of the Gulu rift may have the kinematic component of strike slip in addition to the movement property of normal fault extension. The eastern margin fault of the Gulu rift could be regarded as the extension fault of the Beng Co fault. However, this inference requires additional support from other geophysical evidence. 5.3 Post-seismic relaxation effects of two large earthquakes In 1951 and 1952, two earthquakes with magnitudes of 8.0 and 7.5 occurred along the eastern segment of the Beng Co fault and the Gulu rift, respectively (Tapponnier et al. 1981; Armijo et al. 1989). Previous studies have suggested that the deformation signals were related to the post-seismic relaxation effects of the two earthquakes (Garthwaite et al. 2013; Ryder et al. 2014). The latest wide-swath SAR data contain more global features and provide more detailed information to help us clarify the motion characteristics of conjugate structural zones. Fig. 3 shows that the obvious characteristics of long-wavelength interseismic deformation occur on both sides of the Beng Co fault; however, inconsistent signals were caused by the east–west extension in Peng Co Lake and Dong Co Lake. Tom Ingleby and Wright compiled the maximum post-seismic velocity from published articles and found that transient deformation following earthquakes is measurable (i.e. >1 mm yr–1) for between ∼3 and 100 yr after an earthquake (Wright 2016; Ingleby & Wright 2017). Sixty-five years after the earthquakes, the post-earthquake effect may have still occurred, although the signals would be relatively weak. In addition, the arctangent curve feature of the interseismic deformation is obvious in both the eastern and western segments of the Beng Co fault (Fig. 4). Thus, we infer that the surface deformation along the Beng Co fault may be predominantly comprise interseismic signals. 5.4 Deformation related to lake water loading Ductile deformation in the lower crust and upper mantle may be caused by the mechanical response to changes in lake water levels in the Qinghai-Tibetan Plateau. Many studies have used InSAR data to observe deformations of the lithosphere caused by lake loading (Doin et al. 2015; Zhao et al. 2016). Nam Co Lake is the most influential lake in the study area. In recent years, the water level of Nam Co Lake has risen and the loading of the increased lake water volume mainly results in subsidence effects. From the vertical deformation obtained through inversion from ascending and descending data (Fig. S8), no obvious signal of surface subsidence is observed around Nam Co Lake. In addition, other small lakes do not contribute clear subsidence signals. Therefore, ignoring the loading effect of lake water mass in this work is appropriate. 6 CONCLUSIONS We investigated the present-day slip rates of active faults in Beng Co-Dongqiao conjugate faults to better understand the tectonic environment of the V-shaped conjugate strike-slip fault systems in central Tibet. Our approach of combining GPS velocities with wide-swath InSAR LOS displacements yields detailed interseismic deformation rate maps that can be used to distinguish the spatial inhomogeneity of the deformation for one representative fault system in central Tibet. The two fault segments (the eastern and western parts) of the Beng Co fault zone behave differently. The fault-parallel horizontal deformation rate along the eastern segment of the Beng Co fault reaches 5 ± 1 mm yr–1, whereas that of the western segment is only 2.5 ± 1 mm yr–1. The locking depths of the eastern and western segments of the Beng Co fault were determined to be relatively shallow at 11 and 7 km, respectively. From the small extensional and sinistral deformation signals and strain rates fields, we found geodesy evidence that the Anduo-Peng Co fault system pairs with the eastern segment of Beng Co fault to form a new conjugate fault system, possibly suggesting that the north–south shortening and east–west extension of the central Tibet is accommodated by numerous small and slow slipping V-shaped fault systems instead of by only a few large and fast slipping strike-slip faults, for example the Beng Co-Dongqiao fault system or the Gyaring Co-Riganpei Co fault system. The velocity and strain rate maps indicate a possible dynamic relationship between the Beng Co fault and the Gulu rift. The dextral strike slip motion of the Beng Co fault has undergone tectonic transformation at the end of eastern segment and may control the graben basin formation and current extensional deformation of Gulu rift. The Beng Co-Dongqiao conjugate fault system is one of the most prominent geomorphological features in central Tibet, and determining the coupling mechanisms for active faults in this system is of great importance for investigating the present-day crustal dynamics of the Tibetan Plateau. Our methods and ideas can be expanded to other regions in central Tibet to determine the crustal dynamics throughout the entire plateau interior. SUPPORTING INFORMATION Figure S1. Temporal and spatial baseline of Sentinel-1 Track 41. Figure S2. Temporal and spatial baseline of Sentinel-1 Track 48. Figure S3. Temporal and spatial baseline of Sentinel-1 Track 150. Figure S4. Simulated interseismic deformation phase of Track 150 based on the screw dislocation model and GPS velocities. Figure S5. Long-wavelength phase effects on the T150 interferogram of 20160102–20180220 and the correction process. (a) Original unwrapped interferogram with noisy long-wavelength tropospheric delay errors. (b) Modelled atmospheric phase delay from HRES-ECMWF data using the GACOS method (Yu et al. 2017, 2018). (c) Unwrapped interferogram after correcting ECMWF atmospheric delay. Many long-wavelength signals remain, including interseismic deformation signals and other the long-wavelength phase sources, such as orbit errors and the atmospheric phase delay. (d) Interferogram is generated by subtracting the estimated interseismic signal from (c). The interseismic deformation signal is estimated using the simulated annually averaged deformation phase in Fig. S4 and the time interval of the interferometric pair. (e) Estimated first-order phase ramp based on (d). After removing the interseismic deformation signal (d), a first-order spatial non-deformed long-wavelength phase ramp (e) is calculated by selecting a series of ground control points (GCPs) on (d). (f) Corrected interferogram after subtracting (e) from (c). The simulated long-wavelength phase of (e) is subtracted from the interferogram of (c). Finally, the retained phase of (f) is dominated by the interseismic deformation signal and is less affected by long-wavelength atmospheric errors. Figure S6. InSAR LOS deformation rate map of T150. Figure S7. InSAR LOS deformation rate map of T48. Figure S8. Vertical deformation rate map. The positive values indicate the vertical upward movement, and the negative values indicate vertical downward movement. Figure S9. Profiles corresponding to the dotted lines shown in the Fig. 5. The red dotted lines represent the fault line in the Fig. 5(a)–(d) represent the profiles 1–4 in Fig. 5(a). these values are the extensional deformation rates across the fault. Positive indicates southeast movement and negative indicates northwest movement. Panels (e)–(h) indicate profiles 1–4 in the Fig. 5(b), and these values are the sinistral strike-slip deformation rate along the fault. Positive values indicate the movement to the northeast, and negative values indicate the movement to the southwest. Figure S10. SAR image of the pull-apart basin in the extensional area along the Beng Co dextral strike-slip fault. The Beng Co fault consists of two segments faults oriented the NW–SE and the right-lateral strike-slip characteristics of the fault zone can be interpreted from the fault geomorphology. According to the large-scale pull-apart basin distributed along the fault zone and the local right-lateral right-order oblique surface rupture, the Beng Co active fault zone can be inferred to form a typical pull-apart basin. Figure S11. Focal mechanisms of major historical earthquakes (1970 to 2018) in the study region from the Global CMT Catalogue (https://www.globalcmt.org/CMTsearch.html) Table S1. GPS data used in this study. The reference frame is the Eurasia-fixed. Table S2. Sentinel-1 data used in this study. Please note: Oxford University Press is not responsible for the content or functionality of any supporting materials supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the paper. ACKNOWLEDGEMENTS This work was supported by National Natural Science Foundation of China under Grant (grant number 41704051, 41772219) and research grants from Institute of Crustal Dynamics, China Earthquake Administration (grant numbers No. ZDJ2018-16). This research was also supported by a China Scholarship Council (CSC) Scholarship (CSC NO. 201804190026) held by Yongsheng Li at Newcastle University, UK. The Sentinel-1 data are freely available from the European Space Agency (https://scihub.copernicus.eu/dhus/#/home). REFERENCES Armijo R. , Tapponnier P. , Mercier J.L. , Han T.L. , 1986 . Quaternary extension in southern Tibet: field observations and tectonic implications , J. geophys. Res. , 91 ( B14 ), 13 803 – 13 872 . 10.1029/JB091iB14p13803 Google Scholar Crossref Search ADS WorldCat Crossref Armijo R. , Tapponnier P. , Han T. , 1989 . Late Cenozoic right-lateral strike-slip faulting in southern Tibet , J. geophys. Res. , 94 ( B3 ), 2787 – 2838 . 10.1029/JB094iB03p02787 Google Scholar Crossref Search ADS WorldCat Crossref Blisniuk P.M. , Hacker B.R. , Glodny J. , Ratschbacher L. , Bi S. , Wu Z. , Calvert A. , 2001 . Normal faulting in central Tibet since at least 13.5 Myr ago , Nature , 412 ( 6847 ), 628 . 10.1038/35088045 Google Scholar Crossref Search ADS PubMed WorldCat Crossref Berardino P. , Fornaro G. , Lanari R. , Eugenio S. , 2002 . A new algorithm for surface deformation monitoring based on small baseline differential SAR interferograms , IEEE Trans. Geosci. Rem. Sens. , 40 ( 11 ): 2375 – 2383 . 10.1109/TGRS.2002.803792 Google Scholar Crossref Search ADS WorldCat Crossref Biggs J. , Wright T. , Lu Z. , Parsons B. , 2007 . Multi-interferogram method for measuring interseismic deformation: Denali fault, Alaska , Geophys. J. Int. , 170 ( 3 ), 1165 – 1179 . 10.1111/j.1365-246X.2007.03415.x Google Scholar Crossref Search ADS WorldCat Crossref Cavalié O. , Doin M.-P. , Lasserre C. , Briole P. , 2007 . Ground motion measurement in the Lake Mead area, Nevada, by differential synthetic aperture radar interferometry time series analysis: probing the lithosphere rheological structure , J. geophys. Res. , 112 , B03403 , doi:10.1029/2006JB004344 . 10.1029/2006JB004344 Google Scholar Crossref Search ADS WorldCat Crossref Chen Q. , Freymueller J.T. , Wang Q. , Yang Z. , Xu C. , Liu J. , 2004 . A deforming block model for the present-day tectonics of Tibet , J. geophys. Res. , 109 , B01403 , doi:10.1029/2002jb002151 . 10.1029/2002JB002151 OpenURL Placeholder Text WorldCat Crossref Doin M.-P. , Twardzik C. , Ducret G. , Lasserre C. , Guillaso S. , Sun J. , 2015 . InSAR measurement of the deformation around Siling Co Lake: inferences on the lower crust viscosity in Central Tibet , J. geophys. Res. , 120 ( 7 ), 5290 – 5310 . 10.1002/2014JB011768 Google Scholar Crossref Search ADS WorldCat Crossref Gan W. , Zhang P. , Shen Z.K. , Niu Z. , Wang M. , Wan Y. , Zhou D. , Cheng J. , 2007 . Present‐day crustal motion within the Tibetan Plateau inferred from GPS measurements , J. geophys. Res. , 112 , B08416 , doi:10.1029/2005JB004120 . 10.1029/2005JB004120 Google Scholar Crossref Search ADS WorldCat Crossref Garthwaite M.C. , Wang H. , Wright T.J. , 2013 . Broadscale interseismic deformation and fault slip rates in the central Tibetan Plateau observed using InSAR , J. geophys. Res. , 118 , 5071 – 5083 . 10.1002/jgrb.50348 Google Scholar Crossref Search ADS WorldCat Crossref Elliott J.R. , Biggs J. , Parsons B. , Wright T.J. , 2008 . InSAR slip rate determination on the Altyn Tagh Fault, northern Tibet, in the presence of topographically correlated atmospheric delays . Geophys. Res. Lett. , 35 ( 12 ), doi:10.1029/2008GL033659 . 10.1029/2008GL033659 OpenURL Placeholder Text WorldCat Crossref Elliott J.R. , Walters R.J. , Wright T.J. , 2016 . The role of space-based observation in understanding and responding to active tectonics and earthquakes , Nat. Commun. , 7 ( 1 ), 13844 , doi:10.1038/ncomms13844 . 10.1038/ncomms13844 Google Scholar Crossref Search ADS PubMed WorldCat Crossref Han T. , 1983 . Preliminary investigation of deformation belts caused by earthquakes in 1951–1952 in the Dangxiong-Bengcuo area of Tibet , Seismol. Geol. , 5 ( 4 ), 1 – 13 . OpenURL Placeholder Text WorldCat Hussain E. , Wright T.J. , Walters R.J. , Bekaert D.P. , Lloyd R. , Hooper A. , 2018 . Constant strain accumulation rate between major earthquakes on the North Anatolian Fault , Nat. Commun. , 9 ( 1 ), 1392 , doi:10.1038/s41467-018-03739-2 . 10.1038/s41467-018-03739-2 Google Scholar Crossref Search ADS PubMed WorldCat Crossref Ingleby T. , Wright T.J. ( 2017 ). Omori-like decay of postseismic velocities following continental earthquakes . Geophys. Res. Lett. , 44 ( 7 ), 3119 – 3130 . 10.1002/2017GL072865 Google Scholar Crossref Search ADS WorldCat Crossref Jackson J. , McKenzie D.A.N. , Priestley K. , Emmerson B. , 2008 . New views on the structure and rheology of the lithosphere . J. Geol. Soc. , 165 ( 2 ), 453 – 465 . 10.1144/0016-76492007-109 Google Scholar Crossref Search ADS WorldCat Crossref Jin L. , Funning G.J. , 2017 . Testing the inference of creep on the northern Rodgers Creek fault, California, using ascending and descending persistent scatterer InSAR data , J. geophys. Res. , 122 , 2373 – 2389 . OpenURL Placeholder Text WorldCat Jolivet R. , Simons M. , Agram P.S. , Duputel Z. , Shen Z.-K. , 2015 . Aseismic slip and seismogenic coupling along the central San Andreas Fault , Geophys. Res. Lett. , 42 , 297 – 306 . 10.1002/2014GL062222 Google Scholar Crossref Search ADS WorldCat Crossref Khoshmanesh M. , Shirzaei M. , 2018 . Multiscale dynamics of aseismic slip on Central San Andreas Fault . Geophys. Res. Lett. , 45 , 2274 – 2282 . 10.1002/2018GL077017 Google Scholar Crossref Search ADS WorldCat Crossref Kreemer C. , Blewitt G. , Klein E.C. , 2014 . A geodetic plate motion and Global Strain Rate Model , Geochem. Geophys. Geosyst. , 15 , 3849 – 3889 . 10.1002/2014GC005407 Google Scholar Crossref Search ADS WorldCat Crossref Li K. , Kirby E. , Xu X. , Chen G. , Ren J. , Wang D. , 2019 . Rates of Holocene normal faulting along the Dong Co fault in central Tibet, based on 14C dating of displaced fluvial terraces . J. Asian Earth Sci. , 183 , 103962 , doi:10.1016/j.jseaes.2019.103962 . 10.1016/j.jseaes.2019.103962 Google Scholar Crossref Search ADS WorldCat Crossref Lindsey E.O. , Fialko Y. , Bock Y. , Sandwell D.T. , Bilham R. , 2014 . Localized and distributed creep along the southern San Andreas Fault , J. geophys. Res. , 119 , 7909 – 7922 . 10.1002/2014JB011275 Google Scholar Crossref Search ADS WorldCat Crossref Liu C. , Ji L. , Zhu L. , Zhao C. , 2018 . InSAR-constrained interseismic deformation and potential seismogenic asperities on the Altyn Tagh Fault at 91.5–95° E, Northern Tibetan Plateau , Remote Sens. , 10 ( 6 ), 943 , doi:10.3390/rs10060943 . 10.3390/rs10060943 Google Scholar Crossref Search ADS WorldCat Crossref Meade B.J. , 2007 . Present-day kinematics at the India-Asia collision zone , Geology , 35 ( 1 ), 81 – 84 . 10.1130/G22924A.1 Google Scholar Crossref Search ADS WorldCat Crossref Persson P.-O. , Strang G. , 2005 . A simple mesh generator in MATLAB , SIAM Rev. , 46 ( 2 ), 329 – 345 . 10.1137/S0036144503429121 Google Scholar Crossref Search ADS WorldCat Crossref Ryder I. , Wang H. , Bie L. , Andreas R. , 2014 . Geodetic imaging of late postseismic lower crustal flow in Tibet , Earth planet Sci. Lett. , 404 , 136 – 143 . 10.1016/j.epsl.2014.07.026 Google Scholar Crossref Search ADS WorldCat Crossref Shen Z. , Wang M. , Zeng Y. , Wang F. , 2015 . Optimal interpolation of spatially discretized geodetic data . Seismol. Soc. Am., Bull. , 105 ( 4 ), 2117 – 2127 . 10.1785/0120140247 Google Scholar Crossref Search ADS WorldCat Crossref Tapponnier P. , Molnar P. , 1976 . Slip-line field theory and large-scale continental tectonics , Nature , 264 ( 5584 ), 319 – 324 . 10.1038/264319a0 Google Scholar Crossref Search ADS WorldCat Crossref Tapponnier P. , Mercier J.L. , Armijo R. , Tonglin H. , Ji Z. , 1981 . Field evidence for active normal faulting in Tibet , Nature , 294 ( 5840 ), 410 – 414 . 10.1038/294410a0 Google Scholar Crossref Search ADS WorldCat Crossref Taylor M. , Yin A. , Ryerson F.J. , Paul K. , Lin D. , 2003 . Conjugate strike-slip faulting along the Bangong-Nujiang suture zone accommodates coeval east-west extension and north-south shortening in the interior of the Tibetan Plateau , Tectonics , 22 ( 4 ), 1044 , doi:10.1029/2002TC001361 . 10.1029/2002TC001361 Google Scholar Crossref Search ADS WorldCat Crossref Taylor M. , Peltzer G. , 2006 . Current slip rates on conjugate strike-slip faults in central Tibet using synthetic aperture radar interferometry , J. geophys. Res. , 111 , B12402 , doi:10.1029/2005JB004014 . 10.1029/2005JB004014 OpenURL Placeholder Text WorldCat Crossref Taylor M. , Yin A. , 2009 . Active structures of the Himalayan-Tibetan orogen and their relationships to earthquake distribution, contemporary strain field, and Cenozoic volcanism . Geosphere , 5 ( 5 ), 199 – 214 . 10.1130/GES00217.1 Google Scholar Crossref Search ADS WorldCat Crossref Teng J. , Song P. , Liu Y. , Zhang X. , Ma X. , Yan Y. , 2019 . Deep dynamics for the Yadong-Dongqiao-Huluhu rift in the Tibetan plateau . Chinese J. Geophys. (in Chinese) , 62 ( 9 ), 3321 – 3339 . OpenURL Placeholder Text WorldCat Tong X. , Sandwell D.T. , Smith-Konter B. , 2013 . High-resolution interseismic velocity data along the San Andreas Fault from GPS and InSAR , J. geophys. Res. , 118 , 369 – 389 . 10.1029/2012JB009442 Google Scholar Crossref Search ADS WorldCat Crossref Walters R.J. , Holley R.J. , Parsons B. , Wright T.J. , 2011 . Interseismic strain accumulation across the North Anatolian Fault from Envisat InSAR measurements . Geophys. Res. Lett. , 38 ( 5 ), doi:10.1029/2010GL046443 . 10.1029/2010GL046443 OpenURL Placeholder Text WorldCat Crossref Wang H. , Wright T.J. , Biggs J. , 2009 . Interseismic slip rate of the northwestern Xianshuihe fault from InSAR data , Geophys. Res. Lett. , 36 , L03302 , doi:10.1029/2008GL036560 . OpenURL Placeholder Text WorldCat Wang H. , Wright T.J. , Liu‐Zeng J. , Peng L. , 2019 . Strain rate distribution in south‐central Tibet from two-decades of InSAR and GPS . Geophys. Res. Lett. , 46 , 5170 – 5179 . 10.1029/2019GL081916 Google Scholar Crossref Search ADS WorldCat Crossref Wright T. , Parsons B. , England P. , Fielding E. , 2004 . InSAR observations of low slip rates on the major faults of western Tibet , Science , 305 ( 5681 ), 236 – 239 . 10.1126/science.1096388 Google Scholar Crossref Search ADS PubMed WorldCat Crossref Wright T.J. , 2016 . The earthquake deformation cycle . Astron. Geophys. , 54 ( 7 ), 4 – 20 . OpenURL Placeholder Text WorldCat Wu Z. , Deng Q. , 1989 . Deformation features and fracture mechanism of surface rupture of 1951 Bengco, Tibet Ms8 earthquake (In Chinese Edition) , Seismol. Geol. , 11 ( 1 ), 15 – 25 . OpenURL Placeholder Text WorldCat Wu Z. , Zhao X. , Wu Z. , 2005 . Active faults and their kinematic feature at the Amdo-Tsona Graben, central Xizang (In Chinese Edition) , Quater. Sci. , 25 ( 4 ), 490 – 502 . OpenURL Placeholder Text WorldCat Xu C. , Zhu S. , 2019 . Temporal and spatial movement characteristics of the Altyn Tagh fault inferred from 21 years of InSAR observations . J. Geod. , 93 , 1147 – 1160 . 10.1007/s00190-019-01232-2 Google Scholar Crossref Search ADS WorldCat Crossref Yin A. , Harrison T.M. , Ryerson F.J. , Wenji C. , Kidd W.S.F. , Cope P. , 1994 . Tertiary structural evolution of the Gangdese thrust system, southeastern Tibet , J. geophys. Res. , 99 ( B9 ), 18 175 – 18 201 . 10.1029/94JB00504 Google Scholar Crossref Search ADS WorldCat Crossref Yin A. , Taylor M.H. , 2011 . Mechanics of V-shaped conjugate strike-slip faults and the corresponding continuum mode of continental deformation . Bulletin , 123 ( 9-10 ), 1798 – 1821 . OpenURL Placeholder Text WorldCat Yu C. , Li Z. , Penna N.T. , 2017 . Interferometric synthetic aperture radar atmospheric correction using a GPS-based iterative tropospheric decomposition model , Remote Sens. Environ. , 204 , 109 – 121 . 10.1016/j.rse.2017.10.038 Google Scholar Crossref Search ADS WorldCat Crossref Yu C. , Li Z. , Penna N.T. , Crippa P. , 2018 . Generic atmospheric correction model for Interferometric Synthetic Aperture Radar observations . J. geophys. Res. , 123 , 9202 – 9222 . 10.1029/2017JB015305 Google Scholar Crossref Search ADS WorldCat Crossref Zebker H. , Rosen P. , Hensley S. , 1997 , Atmospheric effects in interferometric synthetic aperature radar surface deformation and topographic maps . J. geophys. Res. , 102 , 7547 – 7564 . 10.1029/96JB03804 Google Scholar Crossref Search ADS WorldCat Crossref Zhang J.J. , 2007 . A review on the extensional structures in the northern Himalaya and southern Tibet , Geol. Bull. China , 26 ( 6 ), 639 – 649 . OpenURL Placeholder Text WorldCat Zhao W. , Amelung F. , Doin M.P. , Dixon T.H. , Wdowinski S. , Lin G. , 2016 . InSAR observations of lake loading at Yangzhuoyong Lake, Tibet: constraints on crustal elasticity , Earth planet. Sci. Lett. , 449 , 240 – 245 . 10.1016/j.epsl.2016.05.044 Google Scholar Crossref Search ADS WorldCat Crossref Zheng G. , Wang H. , Wright T.J. , Lou Y. , Zhang R. , Zhang W. , Wei N. , 2017 . Crustal deformation in the India-Eurasia collision zone from 25 years of GPS measurements . J. geophys. Res. , 122 ( 11 ), 9290 – 9312 . 10.1002/2017JB014465 Google Scholar Crossref Search ADS WorldCat Crossref Zhou B. , Liang X. , Lin G. , Tian X. , Zhu G. , Mechie J. , Teng J. , 2019 . Upper crustal weak zone in central Tibet: an implication from three-dimensional seismic velocity and attenuation tomography results , J. geophys. Res. , 124 , 4654 – 4672 . 10.1029/2018JB016653 Google Scholar Crossref Search ADS WorldCat Crossref Zhu G. , Liang X. , Tian X. , Yang H. , Wu C. , Duan Y. , Zhou B. , 2017 . Analysis of the seismicity in central Tibet based on the SANDWICH network and its tectonic implications . Tectonophysics , 702 , 1 – 7 . 10.1016/j.tecto.2017.02.020 Google Scholar Crossref Search ADS WorldCat Crossref © The Author(s) 2020. Published by Oxford University Press on behalf of The Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model)
TI - Present-day interseismic deformation characteristics of the Beng Co-Dongqiao conjugate fault system in central Tibet: implications from InSAR observations
JF - Geophysical Journal International
DO - 10.1093/gji/ggaa014
DA - 2020-04-01
UR - https://www.deepdyve.com/lp/oxford-university-press/present-day-interseismic-deformation-characteristics-of-the-beng-co-ei010L5tkp
SP - 492
VL - 221
IS - 1
DP - DeepDyve
ER -