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Background <p>The three-dimensional structural model of active faults are essential for seismic zoning and hazard assessment. Constructing models that accurately represent fault geometry has become a key focus in seismic research. The northeastern margin of the Tibet Plateau-Ningxia region lies at the junction of the Ordos Block, the Tibet Plateau, and the Alxa Block. This area features a complex geological structure and frequent strong earthquakes, complicating the analysis of seismogenic structures. Due to limitations in early earthquake monitoring and insufficient data, the structural understanding of historical earthquakes in this area remains controversial. In particular, there are differing interpretations of the seismogenic fault and the maximum magnitude of the 1739 Pingluo <Emphasis Type="BoldItalic">M</Emphasis>8 earthquake.</p> Results <p>In this study, using multidisciplinary data—including active fault surface traces, seismic reflection profiles, and magnetotelluric data—a three-dimensional visualization database of the Ningxia region was established for the first time using a 3D modeling platform. Based on data interpretation and a multivariate constraint method for three-dimensional fault modeling, version 1.0 of a 3D model of 14 major active faults in the Ningxia region was constructed, revealing their geometric characteristics in three-dimensional space. On this basis, the seismogenic structure of the 1739 Pingluo <Emphasis Type="BoldItalic">M</Emphasis>8 earthquake in the extensional fault-depression zone of northern Ningxia is further analyzed, and the slip risk of several major active faults in the southern compressional arc zone is discussed. The results indicate that the Pingluo <Emphasis Type="BoldItalic">M</Emphasis>8 earthquake may have triggered cascading ruptures along multiple faults in the Yinchuan Basin. Under the influence of the NE-trending continuous extrusion of the Tibet Plateau, several major active faults in the southern Ningxia compressional arc zone—including the southern segments of the Haiyuan fault and the Xiangshan–Tianjingshan fault, as well as the middle and southern segments of the Sanguankou-Niushoushan-Luoshan fault—exhibit relatively high slip tendencies (Ts ≥ 0.25), indicating elevated seismic risk.</p> Conclusions <p>This study presents the first comprehensive 3D fault model of the Ningxia region. The model enhances the understanding of seismogenic structures associated with historical earthquakes along the northeastern margin of the Tibet Plateau, analyzing the region’s seismogenic environment, and assessing seismic risk.</p>

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Seismic risk study based on 3D active fault model of the Ningxia area, northeastern margin of Tibetan plateau

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年4月20日

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  • Zhaowu Guo,
  • Renqi Lu,
  • Guanshen Liu,
  • Yin Wang,
  • Peng Du,
  • Xuhang Yang,
  • Xiyan Wu,
  • Kang Wang,
  • Xiao Sun,
  • Fang Xu,
  • Jing Yang,
  • Pengfei Wang

摘要

Background

The three-dimensional structural model of active faults are essential for seismic zoning and hazard assessment. Constructing models that accurately represent fault geometry has become a key focus in seismic research. The northeastern margin of the Tibet Plateau-Ningxia region lies at the junction of the Ordos Block, the Tibet Plateau, and the Alxa Block. This area features a complex geological structure and frequent strong earthquakes, complicating the analysis of seismogenic structures. Due to limitations in early earthquake monitoring and insufficient data, the structural understanding of historical earthquakes in this area remains controversial. In particular, there are differing interpretations of the seismogenic fault and the maximum magnitude of the 1739 Pingluo M8 earthquake.

Results

In this study, using multidisciplinary data—including active fault surface traces, seismic reflection profiles, and magnetotelluric data—a three-dimensional visualization database of the Ningxia region was established for the first time using a 3D modeling platform. Based on data interpretation and a multivariate constraint method for three-dimensional fault modeling, version 1.0 of a 3D model of 14 major active faults in the Ningxia region was constructed, revealing their geometric characteristics in three-dimensional space. On this basis, the seismogenic structure of the 1739 Pingluo M8 earthquake in the extensional fault-depression zone of northern Ningxia is further analyzed, and the slip risk of several major active faults in the southern compressional arc zone is discussed. The results indicate that the Pingluo M8 earthquake may have triggered cascading ruptures along multiple faults in the Yinchuan Basin. Under the influence of the NE-trending continuous extrusion of the Tibet Plateau, several major active faults in the southern Ningxia compressional arc zone—including the southern segments of the Haiyuan fault and the Xiangshan–Tianjingshan fault, as well as the middle and southern segments of the Sanguankou-Niushoushan-Luoshan fault—exhibit relatively high slip tendencies (Ts ≥ 0.25), indicating elevated seismic risk.

Conclusions

This study presents the first comprehensive 3D fault model of the Ningxia region. The model enhances the understanding of seismogenic structures associated with historical earthquakes along the northeastern margin of the Tibet Plateau, analyzing the region’s seismogenic environment, and assessing seismic risk.