The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland
Since the turn of the 20th century, glacial thinning has been exposing volcanic mountain slopes around Iceland’s outlet glaciers. In the early 2000s, several slope instabilities appeared around the Svínafellsjökull outlet glacier in Southeast Iceland. The largest of these is located on a slope calle...
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2025-01-01
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| author | Daniel Ben-Yehoshua Sigurður Erlingsson Þorsteinn Sæmundsson Reginald L. Hermanns Eyjólfur Magnússon Robert A. Askew Jóhann Helgason |
| author_facet | Daniel Ben-Yehoshua Sigurður Erlingsson Þorsteinn Sæmundsson Reginald L. Hermanns Eyjólfur Magnússon Robert A. Askew Jóhann Helgason |
| author_sort | Daniel Ben-Yehoshua |
| collection | DOAJ |
| description | Since the turn of the 20th century, glacial thinning has been exposing volcanic mountain slopes around Iceland’s outlet glaciers. In the early 2000s, several slope instabilities appeared around the Svínafellsjökull outlet glacier in Southeast Iceland. The largest of these is located on a slope called Svarthamrar and is defined by a more than 2 km-long fracture system that separates the northernmost part of the mountain, south of Svínafellsjökull. Here we present updated glacier bed topography, a stratigraphical and structural assessment of the Svarthamrar slope, and quantify the destabilizing effect of glacial unloading from 1890 to deglaciated. Our results show that the slope was predisposed to instability by structural discontinuities and a strongly overdeepened glacial trough. Glacial unloading likely controlled the slope destabilization, potentially exacerbated by temporarily steeper hydraulic gradients due to rapid glacier thinning in the late 1990s and 2000s. The load of older landslide deposits on the glacier acts stabilizing on the slope. We propose that future glacial thinning will reduce the slope stability further, making it more susceptible to external triggers, and resulting in reactivation of the deformation and potential failure. Similar trends of destabilization can be expected for many slopes in Iceland and elsewhere. |
| format | Article |
| id | doaj-art-fee068aa0deb40d7b85bf8c185dbdd0e |
| institution | DOAJ |
| issn | 2624-795X |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
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| series | GeoHazards |
| spelling | doaj-art-fee068aa0deb40d7b85bf8c185dbdd0e2025-08-20T02:42:32ZengMDPI AGGeoHazards2624-795X2025-01-0161110.3390/geohazards6010001The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast IcelandDaniel Ben-Yehoshua0Sigurður Erlingsson1Þorsteinn Sæmundsson2Reginald L. Hermanns3Eyjólfur Magnússon4Robert A. Askew5Jóhann Helgason6Faculty of Civil and Environmental Engineering, University of Iceland, 102 Reykjavík, IcelandFaculty of Civil and Environmental Engineering, University of Iceland, 102 Reykjavík, IcelandFaculty of Life and Environmental Sciences, University of Iceland, 102 Reykjavík, IcelandGeological Survey of Norway, 7040 Trondheim, NorwayInstitute of Earth Sciences, University of Iceland, 102 Reykjavík, IcelandNatural Science Institute of Iceland, 210 Reykjavík, IcelandNational Land Survey of Iceland, 300 Akranes, IcelandSince the turn of the 20th century, glacial thinning has been exposing volcanic mountain slopes around Iceland’s outlet glaciers. In the early 2000s, several slope instabilities appeared around the Svínafellsjökull outlet glacier in Southeast Iceland. The largest of these is located on a slope called Svarthamrar and is defined by a more than 2 km-long fracture system that separates the northernmost part of the mountain, south of Svínafellsjökull. Here we present updated glacier bed topography, a stratigraphical and structural assessment of the Svarthamrar slope, and quantify the destabilizing effect of glacial unloading from 1890 to deglaciated. Our results show that the slope was predisposed to instability by structural discontinuities and a strongly overdeepened glacial trough. Glacial unloading likely controlled the slope destabilization, potentially exacerbated by temporarily steeper hydraulic gradients due to rapid glacier thinning in the late 1990s and 2000s. The load of older landslide deposits on the glacier acts stabilizing on the slope. We propose that future glacial thinning will reduce the slope stability further, making it more susceptible to external triggers, and resulting in reactivation of the deformation and potential failure. Similar trends of destabilization can be expected for many slopes in Iceland and elsewhere.https://www.mdpi.com/2624-795X/6/1/1climate changeglacier retreatdebuttressingglacier unloadinglandslideslope stability |
| spellingShingle | Daniel Ben-Yehoshua Sigurður Erlingsson Þorsteinn Sæmundsson Reginald L. Hermanns Eyjólfur Magnússon Robert A. Askew Jóhann Helgason The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland GeoHazards climate change glacier retreat debuttressing glacier unloading landslide slope stability |
| title | The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland |
| title_full | The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland |
| title_fullStr | The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland |
| title_full_unstemmed | The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland |
| title_short | The Destabilizing Effect of Glacial Unloading on a Large Volcanic Slope Instability in Southeast Iceland |
| title_sort | destabilizing effect of glacial unloading on a large volcanic slope instability in southeast iceland |
| topic | climate change glacier retreat debuttressing glacier unloading landslide slope stability |
| url | https://www.mdpi.com/2624-795X/6/1/1 |
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