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Debris-flow release processes investigated through the analysis of multi-temporal LiDAR datasets in north-western Iceland

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dc.contributor Háskóli Íslands
dc.contributor University of Iceland
dc.contributor.author Morino, Costanza
dc.contributor.author Conway, Susan J.
dc.contributor.author Balme, Matthew R.
dc.contributor.author Hillier, John
dc.contributor.author Jordan, Colm
dc.contributor.author Saemundsson, Thorsteinn
dc.contributor.author Argles, Tom
dc.date.accessioned 2020-10-21T13:43:16Z
dc.date.available 2020-10-21T13:43:16Z
dc.date.issued 2018-09-20
dc.identifier.citation Morino, C., Conway, S. J., Balme, M. R., Hillier, J., Jordan, C., Sæmundsson, Þ., and Argles, T. (2019) Debris‐flow release processes investigated through the analysis of multi‐temporal LiDAR datasets in north‐western Iceland. Earth Surf. Process. Landforms, 44: 144– 159. https://doi.org/10.1002/esp.4488.
dc.identifier.issn 0197-9337
dc.identifier.uri https://hdl.handle.net/20.500.11815/2128
dc.description Publisher's version (útgefin grein)
dc.description.abstract Debris flows are fast-moving gravity flows of poorly sorted rock and soil, mixed and saturated with water. Debris-flow initiation has been studied using empirical and experimental modelling, but the geomorphic changes, indicative of different triggering processes, are difficult to constrain with field observations only. We identify signatures to distinguish two different debris-flow release styles by integrating high-resolution multi-temporal remote sensing datasets and morphometric analysis. We analyse debris flows sourced above the town of Ísafjörður (Iceland). Two debris-flow triggering processes were previously hypothesised for this site: (i) slope failure, characterised by landslides evolving into debris flows; and (ii) the fire-hose effect, in which debris accumulated in pre-existing, steep-sided bedrock passages is transported by a surge of water. It is unknown which process dominates and determines the local risk. To investigate this question, we compare airborne LiDAR elevation models and aerial photographs collected in 2007 with similar data from 2013. We find that two new debris-flow tracks were created by slope failures. These are characterised by steep sliding surfaces and lateral leveed channels. Slope failure also occurred in two large, recently active tracks, creating the preparatory conditions for the fire-hose effect to mobilise existing debris. These tracks show alternating zones of fill and scour along their length, and debris stored below the source-area at rest angles >35°. Our approach allows us to identify and quantify the morphological changes produced by slope failure release process, which generated the preparatory conditions for the fire-hose effect. As debris flows are rarely observed in action and morphological changes induced by them are difficult to detect and monitor, the same approach could be applied to other landscapes to understand debris-flow initiation in the absence of other monitoring information, and can improve the identification of zones at risk in inhabited areas near hillslopes with potential for debris flows.
dc.description.sponsorship This work would not have been possible without a postgraduate studentship grant (NE/L002493/1) from the CENTA Doctoral Training Partnership funded by the UK Natural Environment Research Council (NERC) and the British Geological Survey University Funding Initiative Studentship (GA/14S/024, Ref: 284). We thank the NERC Airborne Research Facility Data Analysis Node for obtaining the aerial photography and LiDAR data, for the airborne survey project NERC ARSF 07217a in 2007 and for the airborne survey project NERC ARSF IG13‐11 in 2013. We thank the NERC Geophysical Equipment Facility for technical support and for the loan number 1001. We would like to show our gratitude to Jón Kristinn Helgason (Icelandic Meteorological Office), who provided expertise that greatly improved the manuscript. We acknowledge constructive comments and suggestions from two anonymous reviewers. C. Jordan publishes with permission from the Executive Director of the British Geological Survey.
dc.format.extent 144-159
dc.language.iso en
dc.publisher Wiley
dc.relation.ispartofseries Earth Surface Processes and Landforms;44(1)
dc.rights info:eu-repo/semantics/openAccess
dc.subject Debris flow
dc.subject LiDAR
dc.subject Multi-temporal analysis
dc.subject NW Iceland
dc.subject Release styles
dc.subject Jarðvegsrannsóknir
dc.subject Framburður (jarðfræði)
dc.title Debris-flow release processes investigated through the analysis of multi-temporal LiDAR datasets in north-western Iceland
dc.type info:eu-repo/semantics/article
dcterms.license This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
dc.description.version Peer Reviewed
dc.identifier.journal Earth Surface Processes and Landforms
dc.identifier.doi 10.1002/esp.4488
dc.relation.url https://onlinelibrary.wiley.com/doi/full/10.1002/esp.4488
dc.contributor.department Líf- og umhverfisvísindadeild (HÍ)
dc.contributor.department Faculty of Life and Environmental Sciences (UI)
dc.contributor.school Verkfræði- og náttúruvísindasvið (HÍ)
dc.contributor.school School of Engineering and Natural Sciences (UI)

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