An Investigation on the Characteristics of the Seismic Signals Induced by Overtopping Dam Breach

Deep-seated landslide masses often block rivers and form landslide dams. Most landslide dams are prone to failure by overtopping water and may induce strong surge wave in the downstream. This study discussed the characteristics of dam break surge wave by experimental methods. We established an artificial dam on a creek in Nantou, Taiwan, for the large-scale dam breach test by overtopping. Flume tests in laboratory were also setup to observe the stability and erosion process of model dams. Accelerometers were used to record the vibrational signals induced by the overtopped water. The vibration signals induced by the surge wave were successfully captured. The velocity of the surge wave front was calculated using the time-frequency spectral magnitude obtained from Hilbert-Huang Transform (HHT). The frequency contents of the seismic signals of the surge waves were also analyzed. The erosion process and erosion rate and duration were discussed. The characteristics including frequency range, duration and corresponding processes, of the vibration signals from the artificial dam and flume tests were compared to the analyzed characteristics of the actual landslide dam breach event at Xiaolin, Kaohsiung occurred in 2009 (Feng, 2012).; An artificial dam on a creek in Nantou, Taiwan, for the large-scale dam breach test by overtopping. ; Opening after the large-scale dam breach test by overtopping.