Assessing Rainfall Thresholds for Large-Scale Landslide

H. L. Kuo ； G. W. Lin ； C. Y. Lee ； H. Y. Yin ； S. K. Lee

《Geotechnical Hazard Mitigations: Experiment, Theory and Practice—Proceedings of the 5th International Conference on Geotechnical Engineering for Disaster Mitigation and Rehabilitation》 2017年 (2017/10) Pp. 373-383

https://doi.org/10.6140/9789864371419.201710.0032

摘要

Large-scale landslides caused by extreme rainstorm has become a new challenge of early warning for slope hazard in recent years. However, due to the insufficient observational records in the past, analyzing critical rainfall conditions are fairly obstructed. The information of occurrence time of landslide could be extracted from the seismic signal recorded by adjacent seismic stations. The study collected the seismic records of the Broadband Array in Taiwan for Seismology (BATS) to identify the ground motions triggered by the landslides occurring during 2005-2014 in Taiwan. After eliminating the signals from local and teleseismic earthquakes, 62 landslide-induced seismic signals were interpreted. The seismic signals provided the occurrence time of landslide to assess the rainfall conditions including rainfall intensity (I, mm/hr), duration (D, hr), and cumulative rainfall (R, mm). The comparison between three common rainfall threshold modes (I-D, I-R, and R-D) reveals that duration and cumulative rainfall should be the crucial factors to evolve an early warning mode. Besides, a critical water mode, (I-1.04)．D = 452 mm, involving triple-factors has been established through the analysis of rainfall information from the 62 occurred large-scale landslides.

關鍵字

Large-scale landslide ； Seismic signal ； Rainfall threshold ； Early warning