Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure
The volcanic island of Surtsey, off the south coast of Iceland, was formed by shallow ocean-emergent basaltic volcanism in 1963-1967. There were several episodes of activity, migrating between five vents (Surtur, Surtla, Surtungur, Syrtlingur and Jólnir) to form a discontinuous ~5.8 km-long mostly s...
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University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences
2023
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Online Access: | https://hdl.handle.net/20.500.11815/4163 |
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ftopinvisindi:oai:opinvisindi.is:20.500.11815/4163 2023-06-11T04:13:07+02:00 Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure Sayyadi, Sara Magnús Tumi Guðmundsson Jarðvísindadeild (HÍ) Faculty of Earth Sciences (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland 2023-01-06 https://hdl.handle.net/20.500.11815/4163 en eng University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences 978-9935-9555-8-6 https://hdl.handle.net/20.500.11815/4163 info:eu-repo/semantics/openAccess Jarðeðlisfræði Doktorsritgerðir Surtseyjargosið Surtsey info:eu-repo/semantics/doctoralThesis 2023 ftopinvisindi https://doi.org/20.500.11815/4163 2023-04-26T22:53:21Z The volcanic island of Surtsey, off the south coast of Iceland, was formed by shallow ocean-emergent basaltic volcanism in 1963-1967. There were several episodes of activity, migrating between five vents (Surtur, Surtla, Surtungur, Syrtlingur and Jólnir) to form a discontinuous ~5.8 km-long mostly submarine ridge. Analysis of data from the rudimentary analog seismic network existing in Iceland in the 1960s reveals that the magnitude of completeness for the Surtsey area was ML=2.5. Precursory seismicity (ML<3) is detected for nine days before onset of continuous tremor on 12 November 1963, signaling the onset of a 40-hour long submarine eruption, followed by subaerial explosive activity. Earthquakes during the eruption were mostly related to intrusive activity preceding opening of new vents. A complicated connection emerges between seismic tremor and magma flow rate or style of activity. The highest magma flow rates in the first 10–20 days were associated with relatively low tremor; higher tremor was observed in the weeks that followed, after discharge rate had dropped substantially. No correlation is found between minutes-to-hours variations in explosive activity and tremor. A detailed aeromagnetic survey was conducted in 2021. Spectral analysis, Euler deconvolution and 2.5D forward modeling of selected profiles reveal shallow origin of magnetic anomalies in the area. The subaerial lavas on Surtsey cause the strongest anomalies, while other sources are mostly 0-300 m below seafloor. No indications of significant intrusions are found within and below the structures formed in 1963-1967, confirming that magma fragmentation was dominant in the submarine phases of the Surtsey eruption. Surtsey myndaðist í eldgosi undan suðurströnd Íslands á árunum 1963-1967. Gosvirkni færðist til nokkrum sinnum og alls gaus á fimm stöðum, í Surti, Surtlu, Surtungi, Syrtlingi og Jólni. Myndanirnar eru samtals um 5.8 km á lengd, mynda breiðan en slitróttan hrygg, að stórum hluta neðansjávar. Greining gagna úr því frumstæða ... Doctoral or Postdoctoral Thesis Iceland Surtsey Opin vísindi (Iceland) Jólnir ENVELOPE(-20.626,-20.626,63.292,63.292) Surtsey ENVELOPE(-20.608,-20.608,63.301,63.301) Surtungur ENVELOPE(-20.611,-20.611,63.306,63.306) Syrtlingur ENVELOPE(-20.588,-20.588,63.308,63.308) |
institution |
Open Polar |
collection |
Opin vísindi (Iceland) |
op_collection_id |
ftopinvisindi |
language |
English |
topic |
Jarðeðlisfræði Doktorsritgerðir Surtseyjargosið Surtsey |
spellingShingle |
Jarðeðlisfræði Doktorsritgerðir Surtseyjargosið Surtsey Sayyadi, Sara Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
topic_facet |
Jarðeðlisfræði Doktorsritgerðir Surtseyjargosið Surtsey |
description |
The volcanic island of Surtsey, off the south coast of Iceland, was formed by shallow ocean-emergent basaltic volcanism in 1963-1967. There were several episodes of activity, migrating between five vents (Surtur, Surtla, Surtungur, Syrtlingur and Jólnir) to form a discontinuous ~5.8 km-long mostly submarine ridge. Analysis of data from the rudimentary analog seismic network existing in Iceland in the 1960s reveals that the magnitude of completeness for the Surtsey area was ML=2.5. Precursory seismicity (ML<3) is detected for nine days before onset of continuous tremor on 12 November 1963, signaling the onset of a 40-hour long submarine eruption, followed by subaerial explosive activity. Earthquakes during the eruption were mostly related to intrusive activity preceding opening of new vents. A complicated connection emerges between seismic tremor and magma flow rate or style of activity. The highest magma flow rates in the first 10–20 days were associated with relatively low tremor; higher tremor was observed in the weeks that followed, after discharge rate had dropped substantially. No correlation is found between minutes-to-hours variations in explosive activity and tremor. A detailed aeromagnetic survey was conducted in 2021. Spectral analysis, Euler deconvolution and 2.5D forward modeling of selected profiles reveal shallow origin of magnetic anomalies in the area. The subaerial lavas on Surtsey cause the strongest anomalies, while other sources are mostly 0-300 m below seafloor. No indications of significant intrusions are found within and below the structures formed in 1963-1967, confirming that magma fragmentation was dominant in the submarine phases of the Surtsey eruption. Surtsey myndaðist í eldgosi undan suðurströnd Íslands á árunum 1963-1967. Gosvirkni færðist til nokkrum sinnum og alls gaus á fimm stöðum, í Surti, Surtlu, Surtungi, Syrtlingi og Jólni. Myndanirnar eru samtals um 5.8 km á lengd, mynda breiðan en slitróttan hrygg, að stórum hluta neðansjávar. Greining gagna úr því frumstæða ... |
author2 |
Magnús Tumi Guðmundsson Jarðvísindadeild (HÍ) Faculty of Earth Sciences (UI) Verkfræði- og náttúruvísindasvið (HÍ) School of Engineering and Natural Sciences (UI) Háskóli Íslands University of Iceland |
format |
Doctoral or Postdoctoral Thesis |
author |
Sayyadi, Sara |
author_facet |
Sayyadi, Sara |
author_sort |
Sayyadi, Sara |
title |
Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
title_short |
Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
title_full |
Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
title_fullStr |
Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
title_full_unstemmed |
Geophysical constraints on the formation of the volcanic island of Surtsey in 1963-1967 and its internal structure |
title_sort |
geophysical constraints on the formation of the volcanic island of surtsey in 1963-1967 and its internal structure |
publisher |
University of Iceland, School of Engineering and Natural Sciences, Faculty of Earth Sciences |
publishDate |
2023 |
url |
https://hdl.handle.net/20.500.11815/4163 |
long_lat |
ENVELOPE(-20.626,-20.626,63.292,63.292) ENVELOPE(-20.608,-20.608,63.301,63.301) ENVELOPE(-20.611,-20.611,63.306,63.306) ENVELOPE(-20.588,-20.588,63.308,63.308) |
geographic |
Jólnir Surtsey Surtungur Syrtlingur |
geographic_facet |
Jólnir Surtsey Surtungur Syrtlingur |
genre |
Iceland Surtsey |
genre_facet |
Iceland Surtsey |
op_relation |
978-9935-9555-8-6 https://hdl.handle.net/20.500.11815/4163 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/20.500.11815/4163 |
_version_ |
1768389778662752256 |