論文

査読有り
2017年5月

Anomalous winter-snow-amplified earthquake-induced disaster of the 2015 Langtang avalanche in Nepal

NATURAL HAZARDS AND EARTH SYSTEM SCIENCES
  • Koji Fujita
  • ,
  • Hiroshi Inoue
  • ,
  • Takeki Izumi
  • ,
  • Satoru Yamaguchi
  • ,
  • Ayako Sadakane
  • ,
  • Sojiro Sunako
  • ,
  • Kouichi Nishimura
  • ,
  • WalterW. Immerzeel
  • ,
  • Joseph M. Shea
  • ,
  • Rijan B. Kayastha
  • ,
  • Takanobu Sawagaki
  • ,
  • David F. Breashears
  • ,
  • Hiroshi Yagi
  • ,
  • Akiko Sakai

17
5
開始ページ
749
終了ページ
764
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.5194/nhess-17-749-2017
出版者・発行元
COPERNICUS GESELLSCHAFT MBH

Coseismic avalanches and rockfalls, as well as their simultaneous air blast and muddy flow, which were induced by the 2015 Gorkha earthquake in Nepal, destroyed the village of Langtang. In order to reveal volume and structure of the deposit covering the village, as well as sequence of the multiple events, we conducted an intensive in situ observation in October 2015. Multitemporal digital elevation models created from photographs taken by helicopter and unmanned aerial vehicles reveal that the deposit volumes of the primary and succeeding events were 6.81 +/- 1.54 x 10(6) and 0.84 +/- 0.92 x 10(6) m(3), respectively. Visual investigations of the deposit and witness statements of villagers suggest that the primary event was an avalanche composed mostly of snow, while the collapsed glacier ice could not be dominant source for the total mass. Succeeding events were multiple rockfalls which may have been triggered by aftershocks. From the initial deposit volume and the area of the upper catchment, we estimate an average snow depth of 1.82 +/- 0.46m in the source area. This is consistent with anomalously large snow depths (1.28-1.52 m) observed at a neighboring glacier (4800-5100ma.s.l.), which accumulated over the course of four major snowfall events between October 2014 and the earthquake on 25 April 2015. Considering long-term observational data, probability density functions, and elevation gradients of precipitation, we conclude that this anomalous winter snow was an extreme event with a return interval of at least 100 years. The anomalous winter snowfall may have amplified the disastrous effects induced by the 2015 Gorkha earthquake in Nepal.

Web of Science ® 被引用回数 : 18

リンク情報
DOI
https://doi.org/10.5194/nhess-17-749-2017
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000401811200001&DestApp=WOS_CPL
ID情報
  • DOI : 10.5194/nhess-17-749-2017
  • ISSN : 1561-8633
  • Web of Science ID : WOS:000401811200001

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