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In the last 130 years, Icelandic glaciers have experienced significant mass loss, and numerous paraglacial slope failures have been documented in the country. One such failure occurred in late February 2013, when a large landslide fell onto the Svínafellsjökull outlet glacier in southeast Iceland. Digital elevation models and aerial imagery were used to quantify the glacial and paraglacial changes leading up to the event, reconstructing the processes that occurred during the landslide and the effects of the debris on the glacier surface. Between 1994 and 2013, glacier thinning and glacier-retreat exposed a steep lateral moraine perched on bedrock which later failed and caused the landslide. Increased pore-water pressure after an intense rainstorm and potential fluvial erosion at the toe of the source area are considered to be the primary trigger mechanisms. Morphological evidence indicates multiple phases of movement in the source area and a highly water-rich debris avalanche on Svínafellsjökull. The debris reached a runout distance of almost 4 km and affected an area of about 1.7 km 2 . The estimated displaced volume of the slide is 5.33 AE 0.08 Â 10 6 m 3 , making it the largest documented landslide originating from unconsolidated material in Iceland. The glacier surface ablation beneath the debris
Crevasse‐squeeze ridges (CSRs) are landforms that have been unequivocally linked to surge‐type glaciers. The formation of CSRs has been discussed since they were first defined in the mid‐1980s. Here, we describe geometric CSR networks from the terrestrial glacier forefields of two glaciers in Trygghamna, Western Svalbard. No glacier surges have been observed in Trygghamna; however, the presence of the CSRs signifies past surge activity. Detailed geomorphological maps were constructed, and the spatial context of these landforms described. Cross‐sections of several CSRs highlight ridge architecture, structure and relationships to surrounding landforms and sediments. Most CSRs are symmetrical in cross‐profile, orientated perpendicular or oblique to the ice‐flow direction. Like previous investigations, we observe these ridge networks on top of till and flutes. Additionally, we, for the first time, document CSRs deposited directly on non‐glaciogenic subsurfaces, namely, beach gravels and bedrock. Our findings confirm previous CSR formation theories; basal sediments are squeezed into bottom‐up crevasses during surges, which are subsequently transported englacially until surge termination and are finally released by melt out from stagnant ice. Consequently, a network of CSRs is the product of a significant reorganisation and down‐glacier transport of basal sediment, exemplifying how single surges are agents of glacial sediment redistribution. These formation processes are illustrated in a refined schematic model. The results further contemporary understanding of CSRs in terrestrial surge‐type glacier settings and may also apply to landforms and sediments in certain marine settings and palaeoglacial environments.
<p>The basaltic effusive eruption at Mt. Fagradalsfjall began on March 19, 2021, ending a 781-year hiatus on Reykjanes Peninsula, Iceland. At the time of writing (January 7, 2022), no eruptive activity has been observed since September 18, 2021. To monitor key eruption parameters (i.e., effusion rate and volume), near-real time photogrammetric monitoring was performed using a combination of satellite and airborne stereo images.</p><p>By late September 2021, 32 near real-time photogrammetric surveys were completed, usually processed within 3&#8211;6 hours. The results are a significant achievement in full-scale monitoring of a lava flow-field providing temporal data sets of lava volume, thickness, and effusion rate. This enabled rapid assessment of eruption evolution and hazards to populated areas, important infrastructure, and tourist centers.</p><p>The lava pathways and lava advancement were very complex and changeable as the lava filled and spilled from one valley into another and short-term prediction of the timing of overflow from one valley to another proved challenging. Analysis of thickness maps and thickness change maps show that the lava transport into different valleys varied up to 10 m<sup>3</sup>/s between surveys as lava transport rapidly switched between one valley to another.</p><p>By late September 2021, the mean lava thickness exceeded 30 m, covered 4.8 km<sup>2 </sup>and has a bulk volume of 150 &#177; 3 &#215; 10<sup>6</sup> m<sup>3</sup>. Around the vent the thickness is up to 122 m. The March&#8211;September mean effusion rate is 9.5 &#177; 0.2 m<sup>3</sup>/s, ranging between 1&#8211;8 m<sup>3</sup>/s in March&#8211;April and increasing to 9&#8211;13 m<sup>3</sup>/s in May&#8211;September. This is uncommon for recent Icelandic eruptions, where the highest discharge usually occurs in the opening phase. This behavior may have been due to widening of the conduit by thermo-mechanical erosion with time, and not controlled by magma chamber pressure as is most common in the volcanic zones of Iceland.</p>
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