Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake

The 2015 Mw 7.8 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 i...

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Main Authors: Nick Rosser, Mark Kincey, Katie Oven, Alexander Densmore, Tom Robinson, Dammar Singh Pujara, Ram Shrestha, Jakub Smutny, Kumar Gurung, Sundup Lama, Megh Raj Dhital
Format: Article
Language:English
Published: Elsevier 2021-04-01
Series:Progress in Disaster Science
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2590061721000193
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author Nick Rosser
Mark Kincey
Katie Oven
Alexander Densmore
Tom Robinson
Dammar Singh Pujara
Ram Shrestha
Jakub Smutny
Kumar Gurung
Sundup Lama
Megh Raj Dhital
author_facet Nick Rosser
Mark Kincey
Katie Oven
Alexander Densmore
Tom Robinson
Dammar Singh Pujara
Ram Shrestha
Jakub Smutny
Kumar Gurung
Sundup Lama
Megh Raj Dhital
author_sort Nick Rosser
collection DOAJ
description The 2015 Mw 7.8 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.
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spelling doaj.art-b03168bb92fe46b3975ef4299429c3ca2022-12-21T22:11:08ZengElsevierProgress in Disaster Science2590-06172021-04-0110100159Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal EarthquakeNick Rosser0Mark Kincey1Katie Oven2Alexander Densmore3Tom Robinson4Dammar Singh Pujara5Ram Shrestha6Jakub Smutny7Kumar Gurung8Sundup Lama9Megh Raj Dhital10Department of Geography, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UK; Corresponding author.Department of Geography, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UKDepartment of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne NE1 8ST, United KingdomDepartment of Geography, Durham University, Lower Mountjoy, South Road, Durham DH1 3LE, UKSchool of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne NE1 7RU, UKNSET, Sainbu Bhainsepati Residential Area, Lalitpur, Lalitpur 13775, NepalNSET, Sainbu Bhainsepati Residential Area, Lalitpur, Lalitpur 13775, NepalPeople in Need Nepal, Ranibari Marg, Kathmandu 44600, NepalPeople in Need Nepal, Ranibari Marg, Kathmandu 44600, NepalCentral Department of Geology, Tribhuvan University, Kathmandu 44618, NepalCentral Department of Geology, Tribhuvan University, Kathmandu 44618, NepalThe 2015 Mw 7.8 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.http://www.sciencedirect.com/science/article/pii/S2590061721000193Earthquake-triggered landslidesPost-seismic hazard and riskSatellite mapping
spellingShingle Nick Rosser
Mark Kincey
Katie Oven
Alexander Densmore
Tom Robinson
Dammar Singh Pujara
Ram Shrestha
Jakub Smutny
Kumar Gurung
Sundup Lama
Megh Raj Dhital
Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
Progress in Disaster Science
Earthquake-triggered landslides
Post-seismic hazard and risk
Satellite mapping
title Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
title_full Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
title_fullStr Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
title_full_unstemmed Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
title_short Changing significance of landslide Hazard and risk after the 2015 Mw 7.8 Gorkha, Nepal Earthquake
title_sort changing significance of landslide hazard and risk after the 2015 mw 7 8 gorkha nepal earthquake
topic Earthquake-triggered landslides
Post-seismic hazard and risk
Satellite mapping
url http://www.sciencedirect.com/science/article/pii/S2590061721000193
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