Analysis of historical seismic parameters based on geological hazards from the Xiaonanhai earthquake
Objective As the largest historical seismic event in the Chongqing region, the Xiaonanhai Earthquake holds significant scientific value for deciphering seismogenic parameters to inform regional seismic hazard assessment and anti-seismic fortification standards. This study addresses the critical cha...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
Institute of Geomechanics, Chinese Academy of Geological Sciences
2025-04-01
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| Series: | Dizhi lixue xuebao |
| Subjects: | |
| Online Access: | https://journal.geomech.ac.cn//article/doi/10.12090/j.issn.1006-6616.2025001 |
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| Summary: | Objective As the largest historical seismic event in the Chongqing region, the Xiaonanhai Earthquake holds significant scientific value for deciphering seismogenic parameters to inform regional seismic hazard assessment and anti-seismic fortification standards. This study addresses the critical challenge of scarce observational data in historical earthquake research. Methods A novel methodology for inverting seismic parameters through characteristic earthquake relics has been developed, systematically reconstructing the historical seismic parameters of the Xiaonanhai Earthquake. The interpretation of high-precision remote sensing and field investigations of seismically induced geo-hazards reveal a dominant near-N–S spatial distribution of the landslide clusters triggered by the Xiaonanhai Earthquake, consistent with the elliptical major axis direction of historically documented felt areas. Results This spatial congruence suggests that the NNW-striking Yangtoushan Fault is the seismogenic fault. Detailed remote sensing analyses of landslide orientations, sliding directions, and deposit distributions demonstrate, for the first time, coherent SE-directed motion features across multiple landslide masses, indicating a southeastward coseismic rupture propagation. A comparative analysis of the spatial correlation between geo-hazards and seismogenic structures observed in the Ludian Earthquake, coupled with seismotectonic mechanisms in southeastern Chongqing, further validates the rationality of the derived seismic parameters. Conclusion This study innovatively identifies a "karst–tectonic" composite mechanism: Under persistent NW–SE tectonic stress, bead-like karst caves developed along the fault zone or dominant joint directions form natural weakening zones, inducing stress concentration and ultimately triggering left-lateral strike-slip motion with thrust components. This dual mechanism explains the unique seismic characteristics blending tectonic rupture and karst collapse. [Significance] The proposed "geo-morphodynamic inversion" methodology advances the reconstruction of historical earthquake parameters and provides critical insights for the evaluation of seismic risk in karst terrains. |
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| ISSN: | 1006-6616 |