On the Catchment Sedimentation and Landslides in Ta-Chia River Induced by 1999 Chi-Chi Earthquake
DOI:
https://doi.org/10.64862/ajeg.2025.2sp.135.294Keywords:
Earthquake-induced landslides, Catchment sedimentation, Sediment dynamics, River channel morphology, Ta-Chia River catchment, Typhoon rainfall, Watershed geomorphologyAbstract
Western Taiwan is highly susceptible to landslides and sediment-related hazards due to its steep topography, weak geological formations, active tectonics, and intense typhoon-induced rainfall. This study investigates the relationship between landslides and catchment sedimentation following the 1999 Chi-Chi earthquake (Mw = 7.6) in the Ta-Chia River and Wu-His catchments. Field investigations, satellite imagery, and Digital Terrain Models (DTMs) were used to analyze landslide distribution, sediment production, and river morphology changes during typhoon events Toraji and Mindulle. The results indicate that earthquake-induced landslides significantly increased sediment generation and transport processes. A conceptual sediment equilibrium model demonstrated that landslides strongly influence channel morphology and downstream sedimentation. The findings provide important information for flood hazard assessment, watershed management, reservoir sediment control, and disaster mitigation planning.
References
Dadson, S.J., Hovius, N., Chen, H., Dade, W.B., Hsieh, M.L., Willett, S.D., Hu, J.C., Horng, M.J., Chen, M.C., Stark, C.P., Lague, D., and Lin, J.C., 2004. Earthquake-triggered increase in sediment delivery from an active mountain belt. Geology 32(8), 733–736. https://doi.org/10.1130/G20639.1
Lin, C.W., Shieh, C.L., Yuan, B.D., Shieh, Y.C., Liu, S.H., and Lee, S.Y., 2004. Impact of Chi-Chi earthquake on the occurrence of landslides and debris flows: example from the Chenyulan River watershed, Nantou, Taiwan. Engineering Geology 71(1–2), 49–61. https://doi.org/10.1016/S0013-7952(03)00125-X
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