Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
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DOI：
10.1016/j.pdisas.2021.100159
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发表时间：
2021-03
影响因子：
6.3
通讯作者：
N. Rosser;M. Kincey;K. Oven;A. Densmore;T. Robinson;D. S. Pujara;R. Shrestha;Jakub Smutny
中科院分区：
文献类型：
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作者：
N. Rosser;M. Kincey;K. Oven;A. Densmore;T. Robinson;D. S. Pujara;R. Shrestha;Jakub Smutny
2015年尼泊尔Mw7.8 Gorkha地震在尼泊尔中西部14个地区引发了2万多起山体滑坡。虽然这些山体滑坡的瞬时影响是巨大的，但地震对在随后的几个月和几年内改变降雨引发的山体滑坡的可能性的持续影响仍然知之甚少，而且难以预测。为了深入了解地震以来滑坡的演变情况，以及它对受影响地区居民的影响，开展了详细的时间序列滑坡测绘活动，以监测同震滑坡的演变情况和新的震后滑坡的启动情况。此外，还进行了数值模拟，以模拟未来在季风降雨下作为泥石流的山体滑坡可能重新激活和流失的情况，以确定可能存在风险的地点。这项分析表明，与2015年地震后不久相比，2019年11月的滑坡风险更高，相当大一部分景观受到山体滑坡的影响。我们表明，虽然地震后原有的山体滑坡继续构成大多数危险，但在新的地点也发生了相当数量的山体滑坡。我们通过总结如何将这项工作纳入支持面临滑坡风险的社区的持久解决方案II项目，讨论了这类分析在为面临风险的定居点的重建和管理提供信息方面的价值。最后，我们考虑今后如何利用这些数据为对风险敏感的土地利用规划和灾后恢复提供信息，并减轻尼泊尔及其他地区未来山体滑坡的影响。
The 2015 Mw7.8 Gorkha, Nepal Earthquake triggered in excess of 20,000 landslides across 14 districts of Central and Western Nepal. Whilst the instantaneous impact of these landslides was significant, the ongoing effect of the earthquake on changing the potential for rainfall-triggered landsliding in the months and years that followed has remained poorly understood and challenging to predict. To provide insight into how landsliding has evolved since the earthquake, and how it has impacted those living in the affected area, a detailed time-series landslide mapping campaign was undertaken to monitor the evolution of coseismic landslides and the initiation of new post-seismic landslides. This was supplemented by numerical modelling to simulate the future potential reactivation and runout of landslides as debris flows under monsoon rainfall, identifying locations potentially at risk. This analysis shows that landslide hazard was higher in November 2019 as compared to immediately after the 2015 earthquake, with a considerable portion of the landscape being impacted by landsliding. We show that, while pre-existing landslides continued to pose the majority of hazard in the aftermath of the earthquake, a significant number of landslides also occurred in new locations. We discuss the value of this type of analysis in informing the reconstruction and management of settlements at risk by summarizing how this work was integrated into the project Durable Solutions II, that supported communities at risk from landslides. Finally, we consider how such data could be used in future to inform risk sensitive land-use planning and disaster recovery, and to mitigate the impacts of future landsliding in Nepal and beyond.