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.
Guðmundsson, Snævarr; Björnsson, Helgi; Pálsson, Finnur; Magnússon, Eyjólfur; Sæmundsson, Þorsteinn; Jóhannesson, Tómas
Terminus lakes on the south side of Vatnajökull ice cap, SE-Iceland Journal Article
In: Jökull, vol. 69, pp. 1-34, 2019.
Abstract | Links | BibTeX | Tags: terminus lakes
@article{jokull-2019-p1-34,
title = {Terminus lakes on the south side of Vatnajökull ice cap, SE-Iceland},
author = {Snævarr Guðmundsson and Helgi Björnsson and Finnur Pálsson and Eyjólfur Magnússon and Þorsteinn Sæmundsson and Tómas Jóhannesson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-1-34.pdf},
doi = {10.33799/jokull2019.69.001},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {1-34},
abstract = {Many ice-marginal lakes have formed in front of glacier termini in Iceland in recent decades due to climate warming, particularly at the southern margin of Vatnajökull ice cap where several such lakes grow year-by-year at present. At the same time, most glacier-dammed lakes at the lateral ice margins have shrunk or disappeared because of glacier thinning, and jökulhlaups released from them have become smaller. This paper describes changes in glacial lakes in SE-Iceland, from Skeiðarárjökull west of Öræfi to Hoffellsjökull in Hornafjörður. Lakes started to form in front of several glaciers in this area in the 1930s but most did not grow much until the 1990s, except for Jökulsárlón by Breiðamerkurjökull, which has grown steadily since before the middle of the last century. Currently, there are growing terminus lakes by all the main south-flowing outlet glaciers of Vatnajökull, with a combined area of ~60 km². The subglacial landscape upstream of the termini indicates that the lakes will continue to grow in the coming decades as a consequence of glacier downwasting if the climate warms as projected. These lakes affect the ice flow and the mass and energy balance of the respective glaciers because of their effect on the force balance of the terminus region, the calving of ice into the lakes, and the absorption of heat spent for melting of calved ice fragments and the terminus ice front. The lakes can cause hazard to settlements and travellers in the adjacent area, as landslides on the glaciers that propagate into the lakes can create tsunami waves with a high run-up and sudden, very dangerous flash floods in the glacier forelands.},
keywords = {terminus lakes},
pubstate = {published},
tppubtype = {article}
}
Einarsson, Páll
Historical accounts of pre-eruption seismicity of Katla, Hekla, Öræfajökull and other volcanoes in Iceland Journal Article
In: Jökull, vol. 69, pp. 35-52, 2019.
Abstract | Links | BibTeX | Tags: Hekla, Katla, Öræfajökull
@article{jokull-2019-p35-52,
title = {Historical accounts of pre-eruption seismicity of Katla, Hekla, Öræfajökull and other volcanoes in Iceland},
author = {Páll Einarsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-35-52.pdf},
doi = {10.33799/jokull2019.69.035},
year = {2019},
date = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {35-52},
abstract = {Detecting unusual activity leading to the outbreak of a volcanic eruption is of vital importance for the short-term warning to the local population of an impending eruption. The varied volcano types of Iceland and range of ambient conditions at which eruptions occur offer an unusually wide spectrum of volcanic phenomena and volcanic hazards during the initial phase of eruptions. A recent study of eruptions in Iceland during the last four decades of instrumental observations has revealed that all the eruptions had a detectable precursory seismic activity, that under favourable conditions can be used to issue short-term warnings to the surrounding communities. Considerable documentary data also exist for pre-instrumental times extending several centuries back in time, that can be compared to the instrumental experience. This is true in particular for two of the most active volcanoes, Katla and Hekla, that are sufficiently close to the populated areas of the country. All seven confirmed eruptions of Katla since 1625 were preceded by felt earthquakes, beginning one to nine hours before the eruption was detected and two to over twelve hours before a jökulhlaup from this partly sub-glacial volcano reached the inhabited areas. The behaviour of Hekla is quite different. Large eruptions from the main edifice of Hekla since 1510 were generally accompanied by rather weak seismic activity. Earthquakes are usually felt only minutes before the first explosion occurs, in the 1947 case even several minutes after the first explosion of the volcano. Eruptions of the Hekla volcanic system outside the main edifice are, on the other hand, accompanied by considerable seismic activity, and the precursor times may be more than three hours, even much longer. The two historical eruptions of Öræfajökull, in 1362 and 1727, were apparently preceded by felt seismicity, sufficient to alarm the local population.},
keywords = {Hekla, Katla, Öræfajökull},
pubstate = {published},
tppubtype = {article}
}
Sgattoni, Giulia; Lucchi, Federico; Einarsson, Páll; Gudmundsson, Ólafur; Astis, Gianfilippo De; Tranne, Claudio Antonio
The 2011 unrest at Katla volcano: seismicity and geology context Journal Article
In: Jökull, vol. 69, pp. 53-70, 2019.
Abstract | Links | BibTeX | Tags: Katla
@article{jokull-2019-p53-70,
title = {The 2011 unrest at Katla volcano: seismicity and geology context},
author = {Giulia Sgattoni and Federico Lucchi and Páll Einarsson and Ólafur Gudmundsson and Gianfilippo De Astis and Claudio Antonio Tranne},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-53-70.pdf},
doi = {10.33799/jokull2019.69.053},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {53-70},
abstract = {Katla is one of the most active volcanoes in Iceland and is characterised by persistent seismicity. It is partly covered by the Mýrdalsjökull glacier and its historic activity is dominated by phreatomagmatic eruptions within the caldera associated with catastrophic glacial floods. In July 2011 a sudden jökulhlaup was released from the glacier, associated with tremor, elevated seismicity inside the caldera and a new cluster of seismicity on the south flank. This was likely caused by a hydrothermal or magmatic event, possibly a small subglacial eruption. Similar unrests occurred in 1955 and 1999. We have identified changes of the seismicity pattern coinciding with the 2011 unrest, suggesting a modification in the volcanic system. It may be speculated that if the persistent seismicity at Katla is an indication of a pressurized magma system ready to erupt, small events like those of 1955, 1999 and 2011 may trigger larger eruptions in the future. We have also conducted a pilot study of the geology of the southern flank, where the new seismicity is recorded, and identified sources for flank eruptions in the recent eruptive history of Katla. These include rhyolitic domes and surtseyan craters. Therefore, a wide range of volcanic processes have to be taken into account as possible source for the new seismicity and volcanic hazard.},
keywords = {Katla},
pubstate = {published},
tppubtype = {article}
}
Pálsson, Magnús; Einarsson, Páll; Hrafnkelsson, Birgir
Variation in b-value of caldera earthquakes during recent activity of the Bárðarbunga Volcano in Iceland Journal Article
In: Jökull, vol. 69, pp. 71-82, 2019.
Abstract | Links | BibTeX | Tags: Bárðarbunga, Holuhraun
@article{jokull-2019-p71-82,
title = {Variation in b-value of caldera earthquakes during recent activity of the Bárðarbunga Volcano in Iceland},
author = {Magnús Pálsson and Páll Einarsson and Birgir Hrafnkelsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-71-82.pdf},
doi = {10.33799/jokull2019.69.071},
year = {2019},
date = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {71-82},
abstract = {The magnitude distribution of caldera earthquakes in the subglacial Bárðarbunga volcano in Central Iceland, characterized by the b-value, shows a systematic variation that is consistent with stress changes anticipated in the roof of an inflating magma chamber beneath the caldera. The b-value was 0.83 prior to the rupture of the chamber in August 2014 when a dike propagated laterally from the volcano to feed the eruption in Holuhraun. The b-value was relatively high following the collapse of the caldera, reflecting low stress in the magma chamber roof. Half a year later a decrease was observed in the b-value, concurrent with an increase in the seismicity, consistent with indications of recharging of the volcano magma chamber. The magnitude distribution was anomalous during the slow collapse of the caldera in association with the eruption. During this period the earthquake sequence appeared to consist of two populations, only one of which followed the conventional Gutenberg–Richter distribution. For a subglacial volcano, where geodetic methods are difficult to implement, the b-value of caldera earthquakes provides an important additional parameter for the monitoring of magma pressure variations.},
keywords = {Bárðarbunga, Holuhraun},
pubstate = {published},
tppubtype = {article}
}
Nikkola, Paavo; Bali, Enikó; Kahl, Maren; van der Meer, Quinten H. A.; Rämö, O. Tapani; Guðfinnsson, Guðmundur H.; Thordarson, Thorvaldur
Crustal magma storage and fractionation of Eyjafjallajökull ankaramites, South Iceland Journal Article
In: Jökull, vol. 69, pp. 83-102, 2019.
Abstract | Links | BibTeX | Tags: Eyjafjallajökull
@article{jokull-2019-p83-102,
title = {Crustal magma storage and fractionation of Eyjafjallajökull ankaramites, South Iceland},
author = {Paavo Nikkola and Enikó Bali and Maren Kahl and Quinten H. A. van der Meer and O. Tapani Rämö and Guðmundur H. Guðfinnsson and Thorvaldur Thordarson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-83-102.pdf},
doi = {10.33799/jokull2019.69.083},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {83-102},
abstract = {Our understanding of the long-term intrusive and eruptive behaviour of volcanic systems is hampered by a relatively short period of direct observation. To probe the conditions of crustal magma storage below South Iceland, we have analysed compositions of minerals, mineral zoning patterns, and melt inclusions from two Eyjafjallajökull ankaramites located at Brattaskjól and Hvammsmúli. These two units are rich in compositionally diverse macrocrysts, including the most magnesian olivine and clinopyroxene known from Eyjafjallajökull. Trends in clinopyroxene macrocryst compositions and the scarcity of plagioclase indicate that the mid-crustal cotectic assemblage was olivine and clinopyroxene, with plagioclase joining the fractionating mineral assemblage later. In all, the crystal cargoes in the Brattaskjól and Hvammsmúli ankaramites are composed of agitated wehrlitic or plagioclase wehrlitic crystal mushes that crystallized over a large temperature interval at mid-crustal depths.},
keywords = {Eyjafjallajökull},
pubstate = {published},
tppubtype = {article}
}
Tussetschläger, Hannah; Brynjólfsson, Skafti; Brynjólfsson, Sveinn; Nagler, Thomas; Sailer, Rudolf; Stötter, Johann; Wuite, Jan
Perennial snow patch detection based on remote sensing data on Tröllaskagi Peninsula, northern Iceland Journal Article
In: Jökull, vol. 69, pp. 103-128, 2019.
Abstract | Links | BibTeX | Tags: remote-sensing, Tröllaskagi
@article{jokull-2019-p103-128,
title = {Perennial snow patch detection based on remote sensing data on Tröllaskagi Peninsula, northern Iceland},
author = {Hannah Tussetschläger and Skafti Brynjólfsson and Sveinn Brynjólfsson and Thomas Nagler and Rudolf Sailer and Johann Stötter and Jan Wuite},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-103-128.pdf},
doi = {10.33799/jokull2019.69.103},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {103-128},
abstract = {The understanding of permafrost distribution in Iceland is still limited and current knowledge is mainly based on small scale observations and regional modelling using temperature data. In the Alps Perennial Snow Patches have been considered to protect permafrost from solar radiation and are used as an indicator for the occurrence of local permafrost. In this study perennial snow fields are detected and classified based on aerial and satellite images. Effects of climatic and topographic factors on the snow field occurrence are investigated aiming to provide insight into the distribution of local permafrost in northern Iceland. Multi-temporal optical satellite images (Landsat-5/-7/-8 and Sentinel-2, 1984–2017) have revealed a time-variable distribution of perennial snow patches as possible permafrost indicators on the Tröllaskagi Peninsula in northern Iceland. Calculated normalized difference snow index in combination with different threshold values at the end of summer season within six selected study areas show that several snow patches are present in a time period of over 30 years. Perennial snow patches in the study areas exhibit strong fluctuations in extent due to different local characteristics, e.g. elevation, aspect or topography (plateau/open slopes vs. valleys/cirques). In three of the six study areas snow patches have a high probability of occurrence and the pattern of the distribution is very similar in each time period. Comparison with climate data from nearby weather stations indicates that perennial snow patches can be used in combination with mean annual air temperatures as indicators for local permafrost distributions.},
keywords = {remote-sensing, Tröllaskagi},
pubstate = {published},
tppubtype = {article}
}
Hannesdóttir, Hrafnhildur
Jöklabreytingar (glacier variations) 1930-1970, 1970-1995, 1995-2017 og 2017-2018 Journal Article
In: Jökull, vol. 69, pp. 129-135, 2019.
Abstract | Links | BibTeX | Tags: glacier variations, sporðamælingar
@article{jokull-2019-p129-135,
title = {Jöklabreytingar (glacier variations) 1930-1970, 1970-1995, 1995-2017 og 2017-2018},
author = {Hrafnhildur Hannesdóttir},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-129-136.pdf},
doi = {10.33799/jokull2019.69.129o},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {129-135},
abstract = {Upplýsingar bárust frá tæplega fimmtíu sporðamælistöðum haustið 2018. Þar af mælist hop á 33 stöðum, framgangur á fimm og fjórir sporðar breytast lítið sem ekkert. Mæling náðist ekki á nokkrum stöðum vegna snjóskafla við jaðar eða fljótandi jaka á lóni framan við jökulinn sem torveldar mælingu með fjarlægðarkíki. Vesturtunga Þórisjökuls bættist við lista sporðamælistaða þegar farin var vettvangsferð í september 2018 og mælistaður staðsettur.},
keywords = {glacier variations, sporðamælingar},
pubstate = {published},
tppubtype = {article}
}
Guðmundsson, Snævarr; Björnsson, Helgi
Breytingar við Breiðamerkurjökul og Hoffellsjökul 2010-2019 (Glacier changes by Breiðamerkurjökull and Hoffellsjökull in 2010-2019 Journal Article
In: Jökull, vol. 69, pp. 137-144, 2019.
Abstract | Links | BibTeX | Tags: glacier variations
@article{jokull-2019-p137-144,
title = {Breytingar við Breiðamerkurjökul og Hoffellsjökul 2010-2019 (Glacier changes by Breiðamerkurjökull and Hoffellsjökull in 2010-2019},
author = {Snævarr Guðmundsson and Helgi Björnsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-137-144.pdf},
doi = {10.33799/jokull2019.69.137o},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {137-144},
abstract = {Athyglisverðar breytingar eiga sér nú stað við jaðra hratt hopandi jökla landsins. Sem dæmi um slíkt greinum við hér frá land- og jöklabreytingum við Breiðamerkurjökul og Hoffellsjökul á árunum 2010–2019, sem höfðu mikil áhrif á afrennsli vatns frá jöklunum, legu farvega, myndun jaðarlóna, jökulhlaup og endalok ísstíflaðs vatns. Í þessum breytingum birtast mikil áhrif rennandi vatns á hop jöklanna.},
keywords = {glacier variations},
pubstate = {published},
tppubtype = {article}
}
Íslands, Jarðfræðafélag
Skýrsla stjórnar fyrir starfsárið (annual report) 2018 Journal Article
In: Jökull, vol. 69, pp. 145-146,, 2019.
Links | BibTeX | Tags: Annual reports
@article{jokull-2019-p145-146,,
title = {Skýrsla stjórnar fyrir starfsárið (annual report) 2018},
author = {Jarðfræðafélag Íslands},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-145-146.pdf},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {145-146,},
keywords = {Annual reports},
pubstate = {published},
tppubtype = {article}
}
Íslands, Jöklarannsóknafélag
Skýrsla formanns fyrir starfsárið (annual report) 2018 á aðalfundi 26. febrúar 2019 Journal Article
In: Jökull, vol. 69, pp. 147-152, 2019.
Links | BibTeX | Tags: Annual reports
@article{jokull-2019-p147-152,
title = {Skýrsla formanns fyrir starfsárið (annual report) 2018 á aðalfundi 26. febrúar 2019},
author = {Jöklarannsóknafélag Íslands},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-147-152.pdf},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {147-152},
keywords = {Annual reports},
pubstate = {published},
tppubtype = {article}
}
Pálsson, Finnur; Guðmundsson, Magnús Tumi
Vorferð Jöklarannsóknafélag Íslands (spring expedition) 29. maí - 9. júní 2019 Journal Article
In: Jökull, vol. 69, pp. 153-156, 2019.
Links | BibTeX | Tags: spring expedition, vorferð
@article{jokull-2019-p153-156,
title = {Vorferð Jöklarannsóknafélag Íslands (spring expedition) 29. maí - 9. júní 2019},
author = {Finnur Pálsson and Magnús Tumi Guðmundsson},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-153-156.pdf},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {153-156},
keywords = {spring expedition, vorferð},
pubstate = {published},
tppubtype = {article}
}
Guðmundsson, Magnús Tumi; Hólmjárn, Jósef
A 25.6 m long firn core extracted from Grímsvötn ice shelf in June 1993 Journal Article
In: Jökull, vol. 69, pp. 157-159, 2019.
Links | BibTeX | Tags: firn, Grímsvötn, ice core
@article{jokull-2019-p157-159,
title = {A 25.6 m long firn core extracted from Grímsvötn ice shelf in June 1993},
author = {Magnús Tumi Guðmundsson and Jósef Hólmjárn},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-157-159.pdf},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {157-159},
keywords = {firn, Grímsvötn, ice core},
pubstate = {published},
tppubtype = {article}
}
Íslands, Jöklarannsóknafélag
Reikningar (accounts) Jörfi 2018 Journal Article
In: Jökull, vol. 69, pp. 160, 2019.
Links | BibTeX | Tags: Annual reports
@article{jokull-2019-p160,
title = {Reikningar (accounts) Jörfi 2018},
author = {Jöklarannsóknafélag Íslands},
url = {https://jokull.jorfi.is/wp-content/uploads/2021/12/J69-160.pdf},
year = {2019},
date = {2019-12-01},
urldate = {2019-12-01},
journal = {Jökull},
volume = {69},
pages = {160},
keywords = {Annual reports},
pubstate = {published},
tppubtype = {article}
}