Rockfall activity in the Kangchenjunga area, Nepal Himalaya

• Published in: Permafrost and Periglacial Processes
• Main Authors: Regmi, Dhananjay, Watanabe, Teiji
• Other Authors: Japan Science Society, Tokachi Mainichi Newspaper Co., Japan
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: Permafrost and Periglacial Processes
• Online Access: http://dx.doi.org/10.1002/ppp.664; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.664; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.664

Abstract Rockfall activity and related environmental factors (i.e. bedrock thermal regime and precipitation) were monitored through most of one year at elevations between 4600 m and 6800 m in the Kangchenjunga valley of the Nepal Himalaya to identify rockfall dynamics, estimate rockfall frequency for different aspects, and assess temporal and spatial variations in rockfall activity. Rockfall activity on north‐facing slopes is mainly controlled by insolation relating to solar elevation and showed an abrupt increase in the pre‐monsoon season. Rockfall activity on east‐, west‐ and south‐facing slopes is controlled by the duration and effectiveness of sunshine and accumulation of snow. The north‐facing slope has a small diurnal range of rock surface temperatures and exhibits seasonal freeze‐thaw, whereas the other aspects show frequent diurnal freeze‐thaw. These differences result in seasonal rockfall activity on the north‐facing slope and the infrequent release of large debris and year‐round rockfall activity on the other aspects. Copyright © 2009 John Wiley & Sons, Ltd.