LIU Fucai, PAN Jiawei, LI Haibing, et al., 2026. Co-seismic surface rupture and seismogenic backgroundof the 1951 M 8.0 Beng Co earthquakein the central Tibetan Plateau. Journal of Geomechanics. DOI: 10.12090/j.issn.1006-6616.2026016
Citation:
LIU Fucai,
PAN Jiawei,
LI Haibing,
et al.,
2026. Co-seismic surface rupture and seismogenic backgroundof the 1951 M 8.0 Beng Co earthquakein the central Tibetan Plateau. Journal of Geomechanics. DOI: 10.12090/j.issn.1006-6616.2026016
LIU Fucai, PAN Jiawei, LI Haibing, et al., 2026. Co-seismic surface rupture and seismogenic backgroundof the 1951 M 8.0 Beng Co earthquakein the central Tibetan Plateau. Journal of Geomechanics. DOI: 10.12090/j.issn.1006-6616.2026016
Citation:
LIU Fucai,
PAN Jiawei,
LI Haibing,
et al.,
2026. Co-seismic surface rupture and seismogenic backgroundof the 1951 M 8.0 Beng Co earthquakein the central Tibetan Plateau. Journal of Geomechanics. DOI: 10.12090/j.issn.1006-6616.2026016
Institute of Geology, Chinese Academy of Geological Sciences
2.
Key Laboratory of Continental Dynamics of Ministry of Natural Resources
3.
Jiangsu Donghai Continental Deep Hole Crustal Activity National Observation and Research Station
4.
State Key Laboratory of Deep Earth and Mineral Exploration
5.
Institute of Geomechanics, Chinese Academy of Geological Sciences
Funds:
National Key Research & Development program(2023YFC3012003);National Natural Science Foundation of China(42325207);Geological Survey Project of the China Geological Survey(DD20240100703);National Natural Science Foundation of China(42372274);Second Tibetan Plateau Scientific Expedition and Research Program (STEP) of the Science and Technology of China(2019QZKK0901)
[Objective] The co-seismic surface rupture formed by an earthquake is the most obvious geomorphological evidence of fault activity. Its spatial distribution and deformation characteristics record essential information about seismic rupture and fault motion, which not only aids in understanding earthquake rupture process and seismogenic mechanism but also contributes significantly to a deeper comprehension of fault evolution and crustal deformation. Therefore, it is of great importance to promptly investigate co-seismic surface rupture zones and acquire high-precision geomorphological data. [Methods] The November 18, 1951 M 8.0 Beng Co earthquake in central Tibet ruptured the Beng Co fault and produced a well-preserved surface rupture zone.. We obtain precise image by combining field investigation with the high-resolution orthomosaic images and digital elevation models (DEMs) derived from unmanned aerial vehicle (UAV) imagery based on the Structure from Motion (SfM) method. Based on these data, we measured both co-seismic and cumulative displacements along the rupture zone to examine the kinematic characteristis of the Beng Co fault and the seismogenic background of the Beng Co earthquake. [Results and conclusions] The earthquake ruptured the eastern segment of the Beng Co fault, forming a ~90 km-long co-seismic surface rupture zone with an overall strike of 120°. A series of right--lateral offset gullies/terraces, push-ups, and pull-aparts along the rupture zone reveal that the Beng Co fault is an active right-lateral strike-slip fault. Cumulative offset probability distribution (COPD) analysis suggests that large earthquakes have occurred repeatedly along this fault and have been fairly characteristic in terms of slip accumulation, with a typical lateral slip of ~4.0 m. The occurrence of the Beng Co earthquake represents a direct response to the Beng Co fault accommodating regional extrusion deformation caused by the rapid eastward movement of the eastern Qiangtang block. [Significance]This work not only facilitates the timely preservation of high-resolution 3D data of the co-seismic surface rupture associated with the Beng Co earthquake but also provides a basis for studying tectonic deformation and assessing seismic hazards in central Tibet.
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