Jökull Journal
Journal of the Iceland Glaciological and Geological Societies
Jökull publishes research papers, notes and review articles concerning all aspects of the Earth Sciences. The journal is primarily aimed at being an international forum for geoscience research in Iceland.
1.
Gunnarsson, Andri; Hannesdóttir, Hrafnhildur
VORFERÐ JÖRFÍ 2022 Journal Article
In: Jökull, vol. 72, pp. 123-127, 2022.
@article{jokull2022.72.123,
title = {VORFERÐ JÖRFÍ 2022},
author = {Andri Gunnarsson and Hrafnhildur Hannesdóttir},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.123.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.123o},
year = {2022},
date = {2022-12-02},
urldate = {2022-12-02},
journal = {Jökull},
volume = {72},
pages = {123-127},
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2.
Wells, Greta H.; Dugmore, Andrew J.; Sæmundsson, Þorsteinn; Beach, Timothy; Luzzadder-Beach, Sheryl; Ben-Yehoshua, Daniel
Geomorphologic evidence of jökulhlaups along the Hvítá river, southwestern Iceland Journal Article
In: Jökull, vol. 72, pp. 35-70, 2022.
Abstract | Links | BibTeX | Tags:
@article{jokull-2022-p35-70,
title = {Geomorphologic evidence of jökulhlaups along the Hvítá river, southwestern Iceland},
author = {Greta H. Wells and Andrew J. Dugmore and Þorsteinn Sæmundsson and Timothy Beach and Sheryl Luzzadder-Beach and Daniel Ben-Yehoshua},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.035.pdf},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Jökull},
volume = {72},
pages = {35-70},
abstract = {Glacial outburst floods (jökulhlaups) have been a significant driver of landscape evolution and environmental change throughout the Quaternary. Iceland experiences more frequent jökulhlaups than nearly anywhere else on Earth, though most research focuses on subglacial volcanogenic floods that drain across outwash plains. Abundant geomorphologic evidence exists for large-scale jökulhlaups that drained along the modern-day course of the Hvítá river in southwestern Iceland during early Holocene deglaciation, originat- ing from ice-dammed Kjölur glacial lake; yet only one previous publication has investigated these events. This study uses a combination of field mapping and remote sensing to identify new jökulhlaup geomorpho- logic evidence along the Hvítá river, including erosional landforms such as scoured bedrock, anastomosing channel networks, cataracts, and canyons, and depositional features such as boulder bars and channel infill. We synthesize new findings with previously reported work to: 1) present an updated geomorphologic map of Hvítá jökulhlaup evidence; 2) reconstruct flood drainage routes, landscape impact, hydrology, and relative chronology; and 3) hypothesize scenarios of ice margin position and glacial lake evolution. Interpreting flood landform assemblages reveals a more extensive geomorphologic record than previously reported, with a com- plex drainage pattern along four separate routes from two potentially different sources. Reconstructed peak flow discharges span three orders of magnitude from 10² to 10⁵ m³s−1. Geomorphologic and paleohydraulic results introduce four hypothesized drainage scenarios, though absolute geochronology is necessary to determine whether multiple floods drained along each route. The Hvítá jökulhlaups yield insight into the timing and dynamics of the final phase of Icelandic Ice Sheet decay, advancing understanding of Iceland’s Pleistocene– Holocene transition, demonstrating the importance of high magnitude, low frequency floods in landscape evo- lution, and serving as an analogue to ice and meltwater response to past, present, and future climate warming in glaciated regions worldwide.},
keywords = {},
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Glacial outburst floods (jökulhlaups) have been a significant driver of landscape evolution and environmental change throughout the Quaternary. Iceland experiences more frequent jökulhlaups than nearly anywhere else on Earth, though most research focuses on subglacial volcanogenic floods that drain across outwash plains. Abundant geomorphologic evidence exists for large-scale jökulhlaups that drained along the modern-day course of the Hvítá river in southwestern Iceland during early Holocene deglaciation, originat- ing from ice-dammed Kjölur glacial lake; yet only one previous publication has investigated these events. This study uses a combination of field mapping and remote sensing to identify new jökulhlaup geomorpho- logic evidence along the Hvítá river, including erosional landforms such as scoured bedrock, anastomosing channel networks, cataracts, and canyons, and depositional features such as boulder bars and channel infill. We synthesize new findings with previously reported work to: 1) present an updated geomorphologic map of Hvítá jökulhlaup evidence; 2) reconstruct flood drainage routes, landscape impact, hydrology, and relative chronology; and 3) hypothesize scenarios of ice margin position and glacial lake evolution. Interpreting flood landform assemblages reveals a more extensive geomorphologic record than previously reported, with a com- plex drainage pattern along four separate routes from two potentially different sources. Reconstructed peak flow discharges span three orders of magnitude from 10² to 10⁵ m³s−1. Geomorphologic and paleohydraulic results introduce four hypothesized drainage scenarios, though absolute geochronology is necessary to determine whether multiple floods drained along each route. The Hvítá jökulhlaups yield insight into the timing and dynamics of the final phase of Icelandic Ice Sheet decay, advancing understanding of Iceland’s Pleistocene– Holocene transition, demonstrating the importance of high magnitude, low frequency floods in landscape evo- lution, and serving as an analogue to ice and meltwater response to past, present, and future climate warming in glaciated regions worldwide.
3.
Hannesdóttir, Hrafnhildur
Jöklabreytingar 1930–1970, 1970–1995, 1995–2020 og 2020–2021 Journal Article
In: Jökull, vol. 72, 2022.
Abstract | Links | BibTeX | Tags:
@article{jokull2022.72.071,
title = {Jöklabreytingar 1930–1970, 1970–1995, 1995–2020 og 2020–2021},
author = {Hrafnhildur Hannesdóttir},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.071.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.071o},
year = {2022},
date = {2022-12-01},
journal = {Jökull},
volume = {72},
abstract = {Sjálfboðaliðar félagsins fóru til sporðamælinga á haustmánuðum 2021. Alls bárust upplýsingar frá rúmlega 30 sporðamælistöðum. Langflestir sporðar hopa og er hörfunin mest á Tungnaárjökli og austanverðum Skeiðarárjökli þar sem hluti af sporðunum hefur losnað frá og hafa þeir hvor um sig styst um 400 m þar sem mælilínan liggur. Sporðlónin framan jöklanna valda erfiðleikum við mælingar eins og undanfarin ár.},
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pubstate = {published},
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Sjálfboðaliðar félagsins fóru til sporðamælinga á haustmánuðum 2021. Alls bárust upplýsingar frá rúmlega 30 sporðamælistöðum. Langflestir sporðar hopa og er hörfunin mest á Tungnaárjökli og austanverðum Skeiðarárjökli þar sem hluti af sporðunum hefur losnað frá og hafa þeir hvor um sig styst um 400 m þar sem mælilínan liggur. Sporðlónin framan jöklanna valda erfiðleikum við mælingar eins og undanfarin ár.
4.
Gunnarsson, Andri; Pálsson, Finnur; Þorsteinsson, Þorsteinn; Hannesdóttir, Hrafnhildur; Brynjólfsson, Skafti
Afkoma íslenskra jökla 2021–2022 Journal Article
In: Jökull, vol. 72, pp. 81-86, 2022.
@article{jokull2022.72.081,
title = {Afkoma íslenskra jökla 2021–2022},
author = {Andri Gunnarsson and Finnur Pálsson and Þorsteinn Þorsteinsson and Hrafnhildur Hannesdóttir and Skafti Brynjólfsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.081.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.079o},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Jökull},
volume = {72},
pages = {81-86},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
5.
Pálsson, Finnur; Björnsson, Helgi; Haraldsson, Hannes H.
Samstarf Landsvirkjunar og Jarðvísindastofnunar Háskólans um jöklarannsóknir 1978 til 2022: Stiklað á stóru Journal Article
In: Jökull, vol. 72, pp. 87-102, 2022.
@article{jokull2022.72.087,
title = {Samstarf Landsvirkjunar og Jarðvísindastofnunar Háskólans um jöklarannsóknir 1978 til 2022: Stiklað á stóru},
author = {Finnur Pálsson and Helgi Björnsson and Hannes H. Haraldsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.087.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.087o},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Jökull},
volume = {72},
pages = {87-102},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
6.
Ólafsson, Halldór
Ferðir til Azoreyja árin 1989 til 1994 Journal Article
In: Jökull, vol. 72, pp. 103-112, 2022.
@article{jokull2022.72.103,
title = {Ferðir til Azoreyja árin 1989 til 1994},
author = {Halldór Ólafsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.103.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.103o},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Jökull},
volume = {72},
pages = {103-112},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
7.
Ólafsson, Halldór
Bylgjubrotsmælingar á Mýrdalsjökli í júní 1991 Journal Article
In: Jökull, vol. 72, pp. 113-116, 2022.
@article{jokull2022.72.113,
title = {Bylgjubrotsmælingar á Mýrdalsjökli í júní 1991},
author = {Halldór Ólafsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2023/02/jokull2022.72.113.pdf},
doi = {https://doi.org/10.33799/jokull2022.72.113o},
year = {2022},
date = {2022-12-01},
urldate = {2022-12-01},
journal = {Jökull},
volume = {72},
pages = {113-116},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
8.
Wuite, Jan; Libert, Ludivine; Nagler, Thomas; Jóhannesson, Tómas
Continuous monitoring of ice dynamics in Iceland with Sentinel-1 satellite radar images Journal Article
In: Jökull, vol. 72, pp. 1–20, 2022.
Abstract | Links | BibTeX | Tags:
@article{jokull72p1-20,
title = {Continuous monitoring of ice dynamics in Iceland with Sentinel-1 satellite radar images},
author = {Jan Wuite and Ludivine Libert and Thomas Nagler and Tómas Jóhannesson},
url = {https://jokull.jorfi.is/wp-content/uploads/2022/10/jokull72p1-20.pdf},
year = {2022},
date = {2022-10-09},
urldate = {2022-10-09},
journal = {Jökull},
volume = {72},
pages = {1--20},
abstract = {In recent years, satellite remote sensing has revolutionized observations of glacier dynamics enabling for the first time the generation of detailed ice-velocity fields at regular intervals for Icelandic glaciers. We generated dense time series of ice-velocity fields from 2014 to 2020 exploiting the continuous acquisition of Sentinel-1 SAR using the offset-tracking technique. The fastest ice flow, with velocities up to 400–800 metres per year, is observed in the middle and lower part of the main outlet glaciers of the ice caps that span a large elevation range in the areas of high precipitation in the South and Southeast of Iceland. Several outlet glaciers of Vatnajökull, such as Skeiðarárjökull and Breiðamerkurjökull, draining towards the South and Southeast, show high-ice-speed channels with pronounced shearing zones where the ice speed increases by an order of magnitude within a distance of only a few ice thicknesses. Velocities on the order of a few tens of metres per
year, and up to 50–100 metres per year, are observed on the large surge-type outlet glaciers of N- and W-Vatnajökull and generally on glaciers in the central Icelandic highland and in the northern and western part of the country. Slow-moving ice is observed along the main ice divides and near the glacier margins. The velocity data set is affected by gaps due to decorrelation, particularly during summer, because of temporal variations in the radar-image texture. The ice-velocity fields derived in this study from Sentinel-1 data agree well with other data sets, although these are affected by a larger number of outliers and data gaps, particularly in the accumulation areas. The generated velocity time series can be used for monitoring long-term dynamic trends, seasonal variations and for studying glaciological events such as surges or jökulhlaups.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In recent years, satellite remote sensing has revolutionized observations of glacier dynamics enabling for the first time the generation of detailed ice-velocity fields at regular intervals for Icelandic glaciers. We generated dense time series of ice-velocity fields from 2014 to 2020 exploiting the continuous acquisition of Sentinel-1 SAR using the offset-tracking technique. The fastest ice flow, with velocities up to 400–800 metres per year, is observed in the middle and lower part of the main outlet glaciers of the ice caps that span a large elevation range in the areas of high precipitation in the South and Southeast of Iceland. Several outlet glaciers of Vatnajökull, such as Skeiðarárjökull and Breiðamerkurjökull, draining towards the South and Southeast, show high-ice-speed channels with pronounced shearing zones where the ice speed increases by an order of magnitude within a distance of only a few ice thicknesses. Velocities on the order of a few tens of metres per
year, and up to 50–100 metres per year, are observed on the large surge-type outlet glaciers of N- and W-Vatnajökull and generally on glaciers in the central Icelandic highland and in the northern and western part of the country. Slow-moving ice is observed along the main ice divides and near the glacier margins. The velocity data set is affected by gaps due to decorrelation, particularly during summer, because of temporal variations in the radar-image texture. The ice-velocity fields derived in this study from Sentinel-1 data agree well with other data sets, although these are affected by a larger number of outliers and data gaps, particularly in the accumulation areas. The generated velocity time series can be used for monitoring long-term dynamic trends, seasonal variations and for studying glaciological events such as surges or jökulhlaups.
year, and up to 50–100 metres per year, are observed on the large surge-type outlet glaciers of N- and W-Vatnajökull and generally on glaciers in the central Icelandic highland and in the northern and western part of the country. Slow-moving ice is observed along the main ice divides and near the glacier margins. The velocity data set is affected by gaps due to decorrelation, particularly during summer, because of temporal variations in the radar-image texture. The ice-velocity fields derived in this study from Sentinel-1 data agree well with other data sets, although these are affected by a larger number of outliers and data gaps, particularly in the accumulation areas. The generated velocity time series can be used for monitoring long-term dynamic trends, seasonal variations and for studying glaciological events such as surges or jökulhlaups.
9.
Sayyadi, Sara; Gudmundsson, Magnús Tumi; Einarsson, Páll
Volcanic tremor associated with the Surtsey eruption of 1963–1967 Journal Article
In: Jökull, vol. 72, 2022.
Abstract | Links | BibTeX | Tags:
@article{jokull72p21-34,
title = {Volcanic tremor associated with the Surtsey eruption of 1963–1967},
author = {Sara Sayyadi and Magnús Tumi Gudmundsson and Páll Einarsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2022/10/jokull72p21-34.pdf},
year = {2022},
date = {2022-10-09},
journal = {Jökull},
volume = {72},
abstract = {The formation of the island of Surtsey over 3.5 years, remains one of the best-documented volcanic, island-forming eruptions to date. The basaltic submarine volcanic activity was detected on November 14, 1963, where ocean depth was 130 m prior to the eruption at the southern end of the Vestmannaeyjar archipelago. The eruptions occurred in several phases involving explosive and effusive activity, including the initial submarine phase on November 12–13, 1963. Separate phases of subaerial volcanic activity occurred during November 14, 1963–January 1964, January–April 1964, April 1964–May 1965, May–October 1965, December 1965–August 1966, and August 1966–June 1967. Seismic data quality from this period is inferior compared to that of modern monitoring systems. Four permanent seismic stations were operated in Iceland at the time, whereof only two, located at 115 and 140 km distance, had the sensitivity to record tremor from Surtsey. Nevertheless, the scanned analog seismograms (http://seismis.hi.is/) show that the eruptive activity was accompanied by considerable seismic activity, both earthquakes, and volcanic tremor. Earthquakes were primarily associated with changes in vent location. Both spasmodic and harmonic tremor was identified, both with low (<3 Hz) and higher (3–5 Hz) characteristic frequencies. The results indicate a complicated relationship between tremor and magma flow rate or style of activity. During the explosive eruption, the highest magma flow rates occurred in
the first 10–20 days, a period with little observed tremor. The highest tremor is observed in December 1963–March 1964, after the discharge rates had dropped substantially, and on a timescale of hours-to-days, no clear relationship between tremor and eruption style is observed. The same applies to the effusive activity, where no seismic tremor was observed during most of the effusive eruption of Surtungur, despite the fact that magma flow rates were 3 times higher than during later phases where some tremor was observed.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The formation of the island of Surtsey over 3.5 years, remains one of the best-documented volcanic, island-forming eruptions to date. The basaltic submarine volcanic activity was detected on November 14, 1963, where ocean depth was 130 m prior to the eruption at the southern end of the Vestmannaeyjar archipelago. The eruptions occurred in several phases involving explosive and effusive activity, including the initial submarine phase on November 12–13, 1963. Separate phases of subaerial volcanic activity occurred during November 14, 1963–January 1964, January–April 1964, April 1964–May 1965, May–October 1965, December 1965–August 1966, and August 1966–June 1967. Seismic data quality from this period is inferior compared to that of modern monitoring systems. Four permanent seismic stations were operated in Iceland at the time, whereof only two, located at 115 and 140 km distance, had the sensitivity to record tremor from Surtsey. Nevertheless, the scanned analog seismograms (http://seismis.hi.is/) show that the eruptive activity was accompanied by considerable seismic activity, both earthquakes, and volcanic tremor. Earthquakes were primarily associated with changes in vent location. Both spasmodic and harmonic tremor was identified, both with low (<3 Hz) and higher (3–5 Hz) characteristic frequencies. The results indicate a complicated relationship between tremor and magma flow rate or style of activity. During the explosive eruption, the highest magma flow rates occurred in
the first 10–20 days, a period with little observed tremor. The highest tremor is observed in December 1963–March 1964, after the discharge rates had dropped substantially, and on a timescale of hours-to-days, no clear relationship between tremor and eruption style is observed. The same applies to the effusive activity, where no seismic tremor was observed during most of the effusive eruption of Surtungur, despite the fact that magma flow rates were 3 times higher than during later phases where some tremor was observed.
the first 10–20 days, a period with little observed tremor. The highest tremor is observed in December 1963–March 1964, after the discharge rates had dropped substantially, and on a timescale of hours-to-days, no clear relationship between tremor and eruption style is observed. The same applies to the effusive activity, where no seismic tremor was observed during most of the effusive eruption of Surtungur, despite the fact that magma flow rates were 3 times higher than during later phases where some tremor was observed.