The Mechanism for Hypermobility of Debris-Ice Avalanches

In recent years, a rising occurrence of catastrophic rock/debris-ice avalanches in high-altitude regions has been witnessed, exhibiting hypermobility. In a changing climate, ice-related geohazards originating from high-altitude regions are expected to become more frequent, posing a great threat to downstream areas. However, the contribution of ice to the hypermobility of debris-ice avalanches (DIAs) remains unclear. This study aims to investigate the mechanisms behind the influence of ice content on the hypermobility of DIAs. A series of centrifuge modelling tests were conducted to simulate the flow process of DIAs, with a cooling system to replicate high-altitude cold environment. The flow dynamics of DIAs was quantified by PIV analysis. It was found the ice content displayed a positive relationship with DIAs mobility. Furthermore, an advanced Bingham model considering ice content was developed to describe the flow behavior of DIAs and further reveal the mechanism for its hypermobility. The findings have broad implications for numerical simulations and hazard mitigation associated with ice-related geohazards.

Keywords: Debris-ice avalanche, Centrifuge modelling test, Hypermobility.