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<p>The lower Jinsha River, situated in the Sichuan-Yunnan region of southwestern China with high seismicity, lies at the tectonic boundary between the Tibetan Plateau and the South China Block. As a critical zone within the Indian-Eurasian plate collision system, it experiences intense crustal deformation and serves as a key tectonic pathway for the eastward extrusion of Tibetan material. Widespread active faults and complex tectonic movements result in frequent seismicity in this region. The impoundment of four large reservoirs constructed since 2012 along the lower Jinsha River may perturb the local tectonic stress field, thereby potentially influencing regional seismicity. To evaluate this effect, we integrate reservoir water level records with geological and geophysical data in a numerical model to quantify stress evolution, map pore pressure diffusion, and analyze corresponding seismicity changes. Our results indicate that surface deformation in the lower Jinsha River region is pronounced, driven primarily by the combined effects of reservoir water load and pore fluid pressure. Pore pressure diffusion exerts a strong influence on the faults near the reservoirs, with a peak increase of approximately 100 kPa localized on the Daliangshan fault. The impoundment of these cascade reservoirs exerts a significant influence on the Coulomb failure stress of the surrounding faults. Coulomb failure stress increments on the Zemuhe, Daliangshan, Xiaojiang, Lianfeng, and Yanfeng faults exceed the stress triggering threshold of 10 kPa, thereby elevating the probability of earthquake occurrence. Our results indicate that the impoundment of the cascade reservoirs has exerted a distinct influence on the regional seismicity pattern. A notable increase in earthquake frequency following impoundment demonstrates a pronounced triggering effect, particularly on nearby strike-slip and thrust faults. Consequently, for the long-term operational safety of the cascade reservoirs, sustained monitoring of seismic activity and associated disaster chains is essential. Our findings provide key insights that inform earthquake prevention and disaster mitigation efforts for the reservoir region.</p>

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Effects of the cascade reservoirs in the Lower Jinsha River on seismicity: Insights from numerical simulations

  • 期刊论文

  • 发表日期：

    2026年5月22日

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  • Zitao Wang,
  • Zhongliang Wu,
  • Yongxian Zhang,
  • Huai Zhang

摘要

The lower Jinsha River, situated in the Sichuan-Yunnan region of southwestern China with high seismicity, lies at the tectonic boundary between the Tibetan Plateau and the South China Block. As a critical zone within the Indian-Eurasian plate collision system, it experiences intense crustal deformation and serves as a key tectonic pathway for the eastward extrusion of Tibetan material. Widespread active faults and complex tectonic movements result in frequent seismicity in this region. The impoundment of four large reservoirs constructed since 2012 along the lower Jinsha River may perturb the local tectonic stress field, thereby potentially influencing regional seismicity. To evaluate this effect, we integrate reservoir water level records with geological and geophysical data in a numerical model to quantify stress evolution, map pore pressure diffusion, and analyze corresponding seismicity changes. Our results indicate that surface deformation in the lower Jinsha River region is pronounced, driven primarily by the combined effects of reservoir water load and pore fluid pressure. Pore pressure diffusion exerts a strong influence on the faults near the reservoirs, with a peak increase of approximately 100 kPa localized on the Daliangshan fault. The impoundment of these cascade reservoirs exerts a significant influence on the Coulomb failure stress of the surrounding faults. Coulomb failure stress increments on the Zemuhe, Daliangshan, Xiaojiang, Lianfeng, and Yanfeng faults exceed the stress triggering threshold of 10 kPa, thereby elevating the probability of earthquake occurrence. Our results indicate that the impoundment of the cascade reservoirs has exerted a distinct influence on the regional seismicity pattern. A notable increase in earthquake frequency following impoundment demonstrates a pronounced triggering effect, particularly on nearby strike-slip and thrust faults. Consequently, for the long-term operational safety of the cascade reservoirs, sustained monitoring of seismic activity and associated disaster chains is essential. Our findings provide key insights that inform earthquake prevention and disaster mitigation efforts for the reservoir region.