Late Quaternary activities of the Xinbaoan–Shacheng fault in the North China Plain

Le résumé fourni par la source

The Xinbaoan–Shacheng Fault is located in the northeastern Huai-Zhuo Basin, where the eastern Jin–Ji–Meng Plateau tectonic zone intersects the Zhangjiakou–Bohai earthquake belt at the North China Plain. As a major active structure, it shows significant Late Pleistocene (Q p 3) activity, yet its slip rate and strong-earthquake recurrence behavior remain poorly constrained. In this study, satellite remote-sensing interpretation, paleoseismic trenching, detailed geological–geomorphic mapping, and Late Pleistocene chronological analysis were integrated to reconstruct its deformation features in the late Quaternary. The fault preserves a composite coseismic rupture scarp 32 km long, striking NW40°–65° and dipping southwest at ~ 70°, with a height of 1.5–3 m, and the statistical magnitude-displacement empirical relationship indicates that it corresponds to a historical earthquake of M 6¾-7. Trench evidence indicates normal-faulting kinematics, with the most recent surface-rupturing event occurring in the late Holocene, plausibly associated with the 1720 M 7 Shacheng earthquake. Deformation–age relationships yield a vertical slip rate of 0.06 ± 0.01 mm/a (R² = 0.97) and a strong-earthquake recurrence interval of 3.39 ± 0.61 ka, characterized by alternating long and short cycles. These results provide robust quantitative constraints on the seismic behavior of the Xinbaoan–Shacheng Fault and offer important implications for regional tectonic evolution and seismic-hazard assessment in the Huai-Zhuo Basin and the whole North China Plain.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.