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On 24 June 2017, a rockslide-debris avalanche occurred in Xinmo Village, Maoxian County, Sichuan Province, China. The displaced materials traveled approximately 2.6 km and caused 83 casualties. Combined with the field investigation, seismic signal, and numerical simulation, the dynamic process and deposit characteristics of the Xinmo landslide were analyzed. Based on the Arias intensity and Hibert time–frequency analysis of the seismic signal, the Xinmo landslide is determined to have a total duration of 120 s and with three-stage dynamic processes, namely, the initial accelerating stage (50 s), erosion impact stage (50 s), and accumulation stage (20 s). Then, taking the field investigation results, the total duration, and kinetic parameters inverted from the seismic signal as criteria, the DAN3D (Dynamic Analysis of Landslides) was employed to reconstruct the dynamic process of the Xinmo landslide. The results show that the erosion and deposit depth distributions obtained from the simulation are in agreement with the pre- and post-landslide DEM (digital elevation model) data and field results. Further, the three-stage dynamic processes (40 s, 60 s, 20 s) obtained from the numerical simulation are also close to the seismic analysis results. In this study, the results of the field investigation and seismic analysis provide a more detailed set of inversion criteria for the numerical simulation work, which contributes to reconstructing the dynamic processes of the Xinmo landslide more accurately. Based on the approach of multi-source data collaboration in this paper, those landslides that lack direct observation data can be better understood and the numerical parameters used for landslide dynamics inversion are better calibrated, which can be applied to predict the runout behavior and disaster scope of potential landslides in the immediate area. [ABSTRACT FROM AUTHOR]

Rock avalanche-induced air blasts are widespread, damaging, and deadly. They can add to the destructive potential of avalanches far beyond the avalanche zone, but no landslide risk assessment in practice to date has accounted for the potential air blast danger. Here, field investigations and numerical studies were employed to quantitively analyze the initiation and propagation mechanism of air blasts triggered by the 2008 Wenjia Valley rock avalanche in Sichuan, China. Our findings indicate that the most significant air blast triggered by the Wenjia Valley avalanche was near bends in the valley, with a maximum pressure of over 25 kPa and a maximum velocity of 73 m/s. The avalanche violently collided with the valley wall at bends, generating multiple destructive air blasts and avalanche deflection. Subsequently, the separated air blast propagated as inertia flows and caused huge forest destruction. A systematic parametric study combined with case studies was further performed to investigate the possible contribution of topography and sliding mass properties to the air blast power. Large avalanche volume and high velocity both appear to be necessary conditions to generate a destructive air blast, while the sudden topography change is also greatly influential. Our work provides new insights into the initiation and propagation of rock avalanche-induced air blasts, compelling to consider this sort of cascading effect during landslide risk assessment in mountainous regions. • Rock avalanche-induced air blasts can cause damage far beyond the sliding mass. • Large avalanche volume and high velocity are necessary conditions to generate powerful air blasts. • Geomorphology is influential in both air blast initiation and propagation. [ABSTRACT FROM AUTHOR]

On 12 May 2008, a catastrophic rock avalanche was triggered by an earthquake in Mianyang, Sichuan, China. This catastrophic event killed 48 people and destroyed some houses at the mouth of Wenjia valley. The sliding mass caused a powerful air blast that blew down the trees on both sides and front margin. To better understand the possible mechanism of the air blast generated by the Wenjia valley rock avalanche and provide information for the assessment of this type of disasters in southwestern China, a numerical simulation was performed through a computational fluid dynamics software (Fluent) to simulate the runout behavior of the sliding mass and dynamic characteristics of the air blast. The frictional rheology is used for the source area and the Voellmy model is selected for the erosion and deposition areas. Simulated results indicate that the movement process of Wenjia valley rock avalanche lasted approximately 210 s with a maximum velocity of 65 m/s. The maximum velocity and relative pressure of the air blast are 35 m/s and 2.25 kPa, respectively. Furthermore, the variation of topography has a significant effect on the distribution of relative pressure for the air blast. The work conducted in this study is expected to make people deeply realize the disaster caused by the air blast and establish a risk assessment system in the southwestern China. [ABSTRACT FROM AUTHOR]