School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TU, UK.
School of Geography, Earth and Environmental Sciences, University of Plymouth, Drakes Circus, Plymouth, PL4 8AA, UK.
Nat Commun. 2021 Nov 18;12(1):6701. doi: 10.1038/s41467-021-26964-8.
In mountainous environments, quantifying the drivers of mass-wasting is fundamental for understanding landscape evolution and improving hazard management. Here, we quantify the magnitudes of mass-wasting caused by the Asia Summer Monsoon, extreme rainfall, and earthquakes in the Nepal Himalaya. Using a newly compiled 30-year mass-wasting inventory, we establish empirical relationships between monsoon-triggered mass-wasting and monsoon precipitation, before quantifying how other mass-wasting drivers perturb this relationship. We find that perturbations up to 5 times greater than that expected from the monsoon alone are caused by rainfall events with 5-to-30-year return periods and short-term (< 2 year) earthquake-induced landscape preconditioning. In 2015, the landscape preconditioning is strongly controlled by the topographic signature of the Gorkha earthquake, whereby high Peak Ground Accelerations coincident with high excess topography (rock volume above a landscape threshold angle) amplifies landscape damage. Furthermore, earlier earthquakes in 1934, 1988 and 2011 are not found to influence 2015 mass-wasting.
在山区环境中，量化块体运动的驱动因素对于理解地貌演化和改进灾害管理至关重要。在这里，我们量化了亚洲夏季风、极端降雨和尼泊尔喜马拉雅地区地震引发块体运动的规模。利用新编制的 30 年块体运动清单，我们在量化其他块体运动驱动因素对这种关系的干扰之前，建立了季风引发块体运动与季风降水之间的经验关系。我们发现，由 5 至 30 年重现期的降雨事件以及短期（<2 年）地震诱发的景观前置条件引起的干扰，可达季风单独作用引起的干扰的 5 倍以上。2015 年，景观前置条件主要受到廓尔喀地震的地形特征的控制，其中与高过剩地形（高于景观阈值角度的岩石体积）相对应的高峰值地面加速度放大了景观破坏。此外，1934 年、1988 年和 2011 年的早期地震并未对 2015 年块体运动产生影响。
