A catastrophic landslide triggered debris flow in China's Yigong: factors, dynamic processes, and tendency
Earth Sciences Research Journal
A Catastrophic Landslide Triggered Debris Flow (CLDF) hazard with a scale of 0.3 billion m3 occurred in the Zhamunong gully on April 9th, 2000. It is of great scientific and engineering significance to study the main controlling factors and dynamic processes of this CLDF, and the future development trend of similar hazards. First, we collect the data of the prehazard precipitation, temperature and earthquake, as well as the seismic waves generated by the disaster. Second, we use multiple
... use multiple methods on the data, including the EPA and SPI computing methods, Fast Fourier transform (FFT), the engineering geological survey, the calculation method of landslide stability, the FLAC numerical simulation method and rock mechanics experiment, etc. Third, the processed data is analyzed, and the results are shown as follows: (1) The motivating factors of the 2000 CLDF were a long-term freeze-thaw cycle, a dry-wet cycle and an earthquake. It is reasonable that the Ms 4.8 earthquake was a direct inducing factor before the occurrence of the 2000 CLDF. (2) Based on the ground vibration spectrum recorded by the Linzhi seismic station, the dynamic processes of the 2000 LTDF have four processes, which are the joint and crack development process in the landslide, the crack fracture and sliding process, the landslide translating into the debris flow and the movement and deposition of the debris flow. (3) The density of the 2000 CLDF is 2.0 t·m-3, the average velocity of the 2000 CLDF is 30.12 m·s-1, and the discharge process of the 2000 CLDF first increases and then decreases. (4) Based on the adequately internal and external geological conditions, a CLDF of the Zhamunong gully may occur in the future. The research results are useful in establishing a foundation for further study on the dynamic mechanism of CLDFs and hazard reduction countermeasures.