Landslide seismic signal recognition and mobility for an earthquake-induced rockslide in Tsaoling, Taiwan

Landslide seismic signal processing and the Newmarkʹs sliding block analysis are used in this research to analyze the initiation time and mobility of the Tsaoling rockslide triggered by the 1999 Chi-Chi Earthquake in Central Taiwan. A new technique, the time–frequency spectrum analysis, is employed to identify the rockslide initiation and landing times from four real time seismic records of strong ground motion stations. The results suggest that higher frequencies ranging from 30 to 70 Hz correspond to the rockslide initiation and sliding process, which are opposed to the low signal frequency of earthquake. The landslide began at 32.5 s, the sliding block sped up at 37.5 s, and impacted on the opposite riverbank at 76 s on the seismic time record. The mobile scenario of Tsaoling rockslide induced by Chi-Chi Earthquake is simulated using Newmarkʹs sliding block analysis. The maximum sliding velocity reaches approximately 75.1 m/s. Despite being a simple conceptual model, the Newmarkʹs sliding block analysis provides consistent results with the real time seismic signal analysis and details of the rockslide kinematics.