Late Quaternary fault activity and deformation mechanism in the eastern Tibet Plateau (Dari fault, Bayan Har Block)

Liang, Mingjian; Wu, Weiwei; Yang, Yu-Miao; Du, Fukuan; Zhou, Wenying; Zuo, Hong; Liao, Cheng; Shao, Lei; Zhang, Huiping

doi:10.1016/j.quaint.2022.09.009

Cited by 3 publications

(6 citation statements)

References 30 publications

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“…The Dari fault (F4 in Figure 1B) is one of several large NWtrending, left-lateral strike-slip faults within the Bayan Har block and has been tectonically active during the Holocene. Liang et al (2022) estimated an average horizontal slip rate of 20 ± 0.3 mm/a since the late Quaternary based on a joint interpretation of highresolution seismic images, field investigations, and trench excavations.…”

Section: Geological Setting and Historical Earthquakesmentioning

confidence: 99%

Seismogenic structures and spatiotemporal seismicity patterns of the 2022 Ms6.0 Maerkang earthquake sequence, Sichuan, China

Feng

GuiXi

et al. 2023

Front. Earth Sci.

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The 2022 Ms6.0 Maerkang earthquake sequence, Sichuan, China, occurred in an unexpected area with historically rare seismicity in the Bayan Har block. Here we relocated the earthquake sequence, inverted for the focal mechanisms of the larger events, and calculated the rupture directivity of the earthquake sequence to reveal the seismogenic structures and mechanisms of this sequence. The high-precision relocations indicate that the seismogenic structures consist of several clusters that are generally parallel to the nearby NW-trending Songgang fault, and relatively small-scale conjugate faults are also identified. The seismicity migrated from cluster one in the south to cluster two in the north during the sequence. Furthermore, the hypocenters were largely located at 5–10 km depth, thereby highlighting that the seismogenic structures are buried. The vertical fault planes of the seismogenic structures are consistent with the high-dip focal mechanism solutions from seven events. A stress field inversion based on the focal mechanisms indicates that the sequence occurred in a strike-slip environment that was controlled by a NNW–SSE-striking principal compressive stress. The different rupture directivities of the Ms5.8 (southwestward) and Ms6.0 (southeastward) events prove the existence of conjugate faults. The Ms5.8 event induced a coseismic Coulomb stress change of 1.6 MPa where the Ms6.0 event subsequently occurred, thereby highlighting that the Ms5.8 event triggered the Ms6.0 event and produced the spatiotemporal seismicity pattern of the sequence. We therefore conclude that the seismogenic structures of the 2022 Ms6.0 Maerkang earthquake sequence are previously unknown concealed conjugate structures associated with the main Songgang fault. The complex seismogenic structures and their potential to generate large earthquakes warrant the need to better understand the seismogenesis of this area and the seismic risks that may be present.

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Section: Geological Setting and Historical Earthquakesmentioning

confidence: 99%

Seismogenic structures and spatiotemporal seismicity patterns of the 2022 Ms6.0 Maerkang earthquake sequence, Sichuan, China

Feng

GuiXi

et al. 2023

Front. Earth Sci.

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“…As shown in Figure 1, earthquakes of ≥M7 have mainly occurred on the boundary faults of the block. However, the AWC, MG, DR, and WC faults in the Aba subblock have late Quaternary activity and structural conditions conducive to the occurrence of major earthquakes [8][9][10][11]. The AWC fault is a left-lateral strike-slip fault with a slip rate in the Holocene of 3 mm/a [11].…”

Section: Tectonic Settingmentioning

confidence: 99%

“…The DR fault, which is located in the middle of the block, and is also a Holocene fault. The horizontal slip rate of the DR fault was 2.6 mm/a, the surface rupture was approximately 70 km produced by the 1947 Dari M7.7 earthquake and it remains well preserved in its middle segment [9,37]. Although the WC fault has Holocene activity [37], reliable determination of the fault parameters has not been realized because of scant research.…”

Section: Tectonic Settingmentioning

confidence: 99%

“…On 22 May 2021, the Madoi M7.4 earthquake occurred on the Jiangcuo fault inside the Bayan Har Block, China [1,2], which is one of the blocks of the Tibetan Plateau that has been most active during the Cenozoic [3][4][5][6][7]. Previously, on 17 March 1947, the Dari M7.7 earthquake occurred on the Dari fault within the block [8,9]. These seismic events indicate that faults within the block also experienced late Quaternary activity and had tectonic conditions capable of producing strong earthquakes.…”

Section: Introductionmentioning

confidence: 99%

“…These seismic events indicate that faults within the block also experienced late Quaternary activity and had tectonic conditions capable of producing strong earthquakes. The Awancang (AWC), Madoi-Garde (MG), Dari (DR), and Wudaoliang-Changshagongma (WC) faults are the main strike-slip faults within the Bayan Har Block, China (Figure 1) [8][9][10][11]; however, their late Quaternary activity has been rarely studied in comparison with that of the boundary faults of the block, which are located on the north and south sides of the interior ones. The WC fault is a large strike-slip fault within the Bayan Har Block that is located to the north of the Garzê-Yushu fault.…”

Section: Introductionmentioning

confidence: 99%

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Holocene Activity of the Wudaoliang–Changshagongma Fault of the Eastern Tibetan Plateau

et al. 2023

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The Wudaoliang–Changshagongma fault is one of the NW-trending faults located within the southern Bayan Har Block of the Tibetan Plateau in China. In this paper, we used high-resolution imagery and digital elevation model data to study the geomorphological and geological characteristics of the fault. Furthermore, the result also determined the fault trace and estimated the average horizontal slip rate of the fault since the late Quaternary to have been 2.6 ± 0.6 mm/a. This slip rate is approximately equivalent to that of the Awancang, Madoi–Garde, and Dari faults, which are also located within the block. Furthermore, the slip rates of these faults obtained by remote sensing and geological methods are consistent with GPS observations. It indicates that tectonic deformation within the block is continuous and diffuse. Using trenching study results and sedimentary radiocarbon dating, we identified four paleoearthquake events that occurred at 42,378–32,975, 33,935–20,663, 5052–4862, and after 673–628 cal BP, respectively. The recurrence intervals of large earthquakes on the faults within the block are much longer than those of the boundary faults, and the slip rates are also smaller, indicating that faults within the block play a regulatory role in the tectonic deformation of the Bayan Har Block.

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Current active fault distribution and slip rate along the middle section of the Jiali-Chayu fault from Sentinel-1 InSAR observations (2017–2022)

Yao,

Wang

et al. 2024

Earth Planets Space

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The Jiali-Chayu fault, situated on the eastern side of the eastern Himalayan syntaxis, is the southeastern margin of the large strike-slip fault zone of the Jiali Fault. The study of the distribution and activity within this fault zone is imperative for a comprehensive understanding of the tectonic movement patterns in the southeastern Tibetan Plateau. Previous studies have established that the kinematic characteristic of the Jiali-Chayu fault diverges significantly from that of other segments within the Jiali fault. Nonetheless, the current tectonic characteristics, including the slip sense, slip rate, and geometric deformation of this fault, are still not well resolved, leading to divergent interpretations regarding its contemporary activity intensity. This paper introduced an optimized time-series InSAR method with phase compensation designed for regions characterized by low coherence and exhibiting slow deformation. Using Sentinel-1 SAR data from both ascending and descending orbits spanning the period between 2017 and 2022, we successfully derived deformation rates for the middle part of the Jiali-Chayu fault at a spatial resolution of 150 m. The slip and dip rates of active faults are determined by considering the fault movement rates from two different observation angles, in conjunction with strike angle and the assumed dip angle of the fault. The results show that the deformation rates of the three branches are very different, with F2-1 and F2-2 exhibiting notable activity, while other areas exhibit relatively weaker activity. The strike-slip rates for F2-1 and F2-2 faults range between 3.6 and 5.3 mm/a and 3.05 to 5.13 mm/a, respectively, while their respective dip-slip rates fall within the range of 1.1–2.7 mm/a and 2.99–5.02 mm/a. In accordance with the fault slip directions, we classify the F2-1 fault as a sinistral (left-lateral) strike-slip fault and the F2-2 fault as a dextral (right-lateral) strike-slip fault. This study addresses a gap in remote sensing methods for detecting active fault activity in this region, providing a systematic foundation for identifying weak activity characteristics within the fault zone. Graphical Abstract

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Late Quaternary fault activity and deformation mechanism in the eastern Tibet Plateau (Dari fault, Bayan Har Block)

Cited by 3 publications

References 30 publications

Seismogenic structures and spatiotemporal seismicity patterns of the 2022 Ms6.0 Maerkang earthquake sequence, Sichuan, China

Seismogenic structures and spatiotemporal seismicity patterns of the 2022 Ms6.0 Maerkang earthquake sequence, Sichuan, China

Holocene Activity of the Wudaoliang–Changshagongma Fault of the Eastern Tibetan Plateau

Current active fault distribution and slip rate along the middle section of the Jiali-Chayu fault from Sentinel-1 InSAR observations (2017–2022)

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