A catastrophic landslide triggered debris flow in China’s Yigong: factors, dynamic processes, and tendency

Abstract

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 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.

Landslide Detection in the Linzhi–Ya’an Section along the Sichuan–Tibet Railway Based on InSAR and Hot Spot Analysis Methods

“…Moreover, the annual deformation rate of most landslides is >100 mm/year and the volume is >1 km 2 . For example, the famous Yigong landslide occurred along the Palalung Zangbo River [22,23]. Regarding the coastal area of the Jinsha River (Figure 6b), several large-scale landslides were distributed in this area and the deformation rates of these slopes were all >100 mm/year, with a maximum of 180 mm/year.…”

“…The Yigong Zangbo River was markedly blocked and the highway was interrupted for several months. It also resulted in large-scale casualties and property losses upstream and downstream [22,23]. In 2018, a large-scale high-level rock landslide occurred in Baige Village, which caused a break in the Jinsha River for 2 days [24].…”

Air Pollutants Sources in Winter in Chang-Zhu-Tan Region of China

“…Based on the HYSPLIT 4 model developed by NOAA (National Oceanic and Atmospheric Administration) and BOM (Australia's Bureau of Meteorology), the 72 h backward airflow trajectories arriving at the research area every 6 hours from December 2019 to February 2020 are calculated. Driven by the global atmospheric reanalysis data of the National Centre for Environmental Prediction (NCEP), the model covers the whole process of transport, diffusion, and deposition and is widely used in pollutant transport path and source area analysis [23].…”

A review of the relation between climate variability and mass removal processes

“…Both the wet-dry cycle and the freeze-thaw cycle originate from temperature variation and are responsible for the cracking in rocky matrices [14]. Temperature also influences the sequence of drought periods that can trigger mass removal processes taking into assumption that previous dry periods are triggers for extreme rainfall [15].…”