A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland
International audience The aim of this study is to improve the assessment of hazard posed by debris flows to the people and settlements of northwest Iceland by studying very recent examples from above the town of Ísafjörður and other nearby localities. Debris flows are a recognised hazard in the reg...
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Online Access: | https://hal.science/hal-00826916 https://hal.science/hal-00826916/document https://hal.science/hal-00826916/file/GEOMOR-CONWAY_4HAL.pdf https://doi.org/10.1016/j.geomorph.2009.08.015 |
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ftecolephe:oai:HAL:hal-00826916v1 2024-05-19T07:42:42+00:00 A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland Susan, Conway Decaulne, Armelle Matthew R., Balme John B., Murray M.C., Towner Department of Environment, Earth and Ecosystems Open University The Open University Milton Keynes (OU) Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes) Université de Caen Normandie (UNICAEN) Normandie Université (NU)-Normandie Université (NU)-École Pratique des Hautes Études (EPHE) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN) Université de Nantes (UN)-Université de Nantes (UN) 2010 https://hal.science/hal-00826916 https://hal.science/hal-00826916/document https://hal.science/hal-00826916/file/GEOMOR-CONWAY_4HAL.pdf https://doi.org/10.1016/j.geomorph.2009.08.015 en eng HAL CCSD Elsevier info:eu-repo/semantics/altIdentifier/doi/10.1016/j.geomorph.2009.08.015 hal-00826916 https://hal.science/hal-00826916 https://hal.science/hal-00826916/document https://hal.science/hal-00826916/file/GEOMOR-CONWAY_4HAL.pdf doi:10.1016/j.geomorph.2009.08.015 info:eu-repo/semantics/OpenAccess ISSN: 0169-555X Geomorphology https://hal.science/hal-00826916 Geomorphology, 2010, pp.556-572. ⟨10.1016/j.geomorph.2009.08.015⟩ debris flow Icelandic Westfjords geohazards LiDAR [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology info:eu-repo/semantics/article Journal articles 2010 ftecolephe https://doi.org/10.1016/j.geomorph.2009.08.015 2024-04-25T01:34:59Z International audience The aim of this study is to improve the assessment of hazard posed by debris flows to the people and settlements of northwest Iceland by studying very recent examples from above the town of Ísafjörður and other nearby localities. Debris flows are a recognised hazard in the region: above Ísafjörður, they occur with particularly high frequency and have appreciable volumes (up to 14 000 m 3). We have used airborne laser altimeter (LiDAR) and differential Global Positioning System (GPS) data to produce isopach maps of flows that occurred in 1999, 2007, and 2008. Our data show that these flows begin depositing at higher slope gradients and are also more mobile than hillslope debris flows reported by other authors. Above a 19° slope, erosion is initiated independent of the distance along the flowpath. Using the isopach maps and associated field observations, we have found a relationship between ground slope and patterns in deposition volume. We have used this finding as a basis for an empirical model that enables an estimate of the total travel distance and final thickness of future debris flows to be calculated. This has enabled us to identify areas of the town which are at risk; some of these are not obvious without this analysis. This model is notable for its simplicity, which allows future debris flow characteristics to be predicted without the need to determine the precise fluid dynamic parameters of the flow such as viscosity and velocity, which are required to implement more complex models. Article in Journal/Newspaper Iceland Ísafjörður EPHE (Ecole pratique des hautes études, Paris): HAL Geomorphology 114 4 556 572 |
institution |
Open Polar |
collection |
EPHE (Ecole pratique des hautes études, Paris): HAL |
op_collection_id |
ftecolephe |
language |
English |
topic |
debris flow Icelandic Westfjords geohazards LiDAR [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology |
spellingShingle |
debris flow Icelandic Westfjords geohazards LiDAR [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology Susan, Conway Decaulne, Armelle Matthew R., Balme John B., Murray M.C., Towner A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
topic_facet |
debris flow Icelandic Westfjords geohazards LiDAR [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology |
description |
International audience The aim of this study is to improve the assessment of hazard posed by debris flows to the people and settlements of northwest Iceland by studying very recent examples from above the town of Ísafjörður and other nearby localities. Debris flows are a recognised hazard in the region: above Ísafjörður, they occur with particularly high frequency and have appreciable volumes (up to 14 000 m 3). We have used airborne laser altimeter (LiDAR) and differential Global Positioning System (GPS) data to produce isopach maps of flows that occurred in 1999, 2007, and 2008. Our data show that these flows begin depositing at higher slope gradients and are also more mobile than hillslope debris flows reported by other authors. Above a 19° slope, erosion is initiated independent of the distance along the flowpath. Using the isopach maps and associated field observations, we have found a relationship between ground slope and patterns in deposition volume. We have used this finding as a basis for an empirical model that enables an estimate of the total travel distance and final thickness of future debris flows to be calculated. This has enabled us to identify areas of the town which are at risk; some of these are not obvious without this analysis. This model is notable for its simplicity, which allows future debris flow characteristics to be predicted without the need to determine the precise fluid dynamic parameters of the flow such as viscosity and velocity, which are required to implement more complex models. |
author2 |
Department of Environment, Earth and Ecosystems Open University The Open University Milton Keynes (OU) Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes) Université de Caen Normandie (UNICAEN) Normandie Université (NU)-Normandie Université (NU)-École Pratique des Hautes Études (EPHE) Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Brest (UBO)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN) Université de Nantes (UN)-Université de Nantes (UN) |
format |
Article in Journal/Newspaper |
author |
Susan, Conway Decaulne, Armelle Matthew R., Balme John B., Murray M.C., Towner |
author_facet |
Susan, Conway Decaulne, Armelle Matthew R., Balme John B., Murray M.C., Towner |
author_sort |
Susan, Conway |
title |
A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
title_short |
A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
title_full |
A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
title_fullStr |
A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
title_full_unstemmed |
A new approach to estimating hazard posed by debris flows in the Westfjords of Iceland |
title_sort |
new approach to estimating hazard posed by debris flows in the westfjords of iceland |
publisher |
HAL CCSD |
publishDate |
2010 |
url |
https://hal.science/hal-00826916 https://hal.science/hal-00826916/document https://hal.science/hal-00826916/file/GEOMOR-CONWAY_4HAL.pdf https://doi.org/10.1016/j.geomorph.2009.08.015 |
genre |
Iceland Ísafjörður |
genre_facet |
Iceland Ísafjörður |
op_source |
ISSN: 0169-555X Geomorphology https://hal.science/hal-00826916 Geomorphology, 2010, pp.556-572. ⟨10.1016/j.geomorph.2009.08.015⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.geomorph.2009.08.015 hal-00826916 https://hal.science/hal-00826916 https://hal.science/hal-00826916/document https://hal.science/hal-00826916/file/GEOMOR-CONWAY_4HAL.pdf doi:10.1016/j.geomorph.2009.08.015 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1016/j.geomorph.2009.08.015 |
container_title |
Geomorphology |
container_volume |
114 |
container_issue |
4 |
container_start_page |
556 |
op_container_end_page |
572 |
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