Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary
The rifting of the plate boundary in north Iceland forms new ground fissures and reactivates old ones. Continuous growth of fissures is observed in the crust above a magma chamber beneath the Krafla caldera as it responds to changes in subterranean magma pressure. Rapid episodes of fissure formation...
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American Geophysical Union
1983
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ftcaltechauth:oai:authors.library.caltech.edu:jg48g-fjk02 2024-06-23T07:54:01+00:00 Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary Hauksson, Egill 1983-01 https://doi.org/10.1029/JB088iB01p00625 unknown American Geophysical Union https://doi.org/10.1029/JB088iB01p00625 oai:authors.library.caltech.edu:jg48g-fjk02 eprintid:38334 resolverid:CaltechAUTHORS:20130507-150226907 info:eu-repo/semantics/openAccess Other Journal of Geophysical Research B, 88(B1), 625-636, (1983-01) info:eu-repo/semantics/article 1983 ftcaltechauth https://doi.org/10.1029/JB088iB01p00625 2024-06-12T02:32:29Z The rifting of the plate boundary in north Iceland forms new ground fissures and reactivates old ones. Continuous growth of fissures is observed in the crust above a magma chamber beneath the Krafla caldera as it responds to changes in subterranean magma pressure. Rapid episodes of fissure formation and reactivation are observed in conjunction with magma intrusions at depth along the rift zone that constitutes the plate boundary between the North American and Eurasian plates. The Krafla caldera contains several fissures that open during periods of uplift lasting 100 to 300 days and that close incompletely in subsidence episodes lasting several hours to 3 weeks. The average rate of opening differs from one period to another, ranging from 0.1 to 0.5 mm/d. Fissure closing and average closing rates also vary from one subsidence episode to another, ranging from minimal values of 2.1 mm and 2.3 mm/d to maximal values of 49 mm and 18 mm/d, respectively. During the two intrusion episodes of September 1977 and March 1980 the magma migrated toward the south with an average velocity 0.6 and 0.5 m/s, respectively. In the September 1977 episode some fissures in the rift zone widened with a rate greater than 190 mm/d, whereas during the March episode that probably resulted in a thinner intrusion the maximum widening rate was only 50 mm/d. The data suggest that the magnitude of a subsidence episode is determined at least partly by the available excess magma pressure in the chamber. To explain the extensive growth of open fissures and normal faulting in the rift zone, it is necessary to assume that in addition to the intrusion of the main central dike at depth, many small dikes are intruded at shallow depths (less than 1 km). © 1983 by the American Geophysical Union. Received May 14, 1982; revised August 27, 1982; accepted October 22, 1982. The author wishes to thank Roger Bilham, Lucile M. Jones, and Terry Engelder for critically reviewing the manuscript. Pall Einarsson, Bryndis Brandsdottir, Axel Bjornsson, and Robert O. ... Article in Journal/Newspaper Iceland Caltech Authors (California Institute of Technology) Krafla ENVELOPE(-16.747,-16.747,65.713,65.713) New Ground ENVELOPE(-55.215,-55.215,49.567,49.567) Journal of Geophysical Research: Solid Earth 88 B1 625 636 |
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Caltech Authors (California Institute of Technology) |
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description |
The rifting of the plate boundary in north Iceland forms new ground fissures and reactivates old ones. Continuous growth of fissures is observed in the crust above a magma chamber beneath the Krafla caldera as it responds to changes in subterranean magma pressure. Rapid episodes of fissure formation and reactivation are observed in conjunction with magma intrusions at depth along the rift zone that constitutes the plate boundary between the North American and Eurasian plates. The Krafla caldera contains several fissures that open during periods of uplift lasting 100 to 300 days and that close incompletely in subsidence episodes lasting several hours to 3 weeks. The average rate of opening differs from one period to another, ranging from 0.1 to 0.5 mm/d. Fissure closing and average closing rates also vary from one subsidence episode to another, ranging from minimal values of 2.1 mm and 2.3 mm/d to maximal values of 49 mm and 18 mm/d, respectively. During the two intrusion episodes of September 1977 and March 1980 the magma migrated toward the south with an average velocity 0.6 and 0.5 m/s, respectively. In the September 1977 episode some fissures in the rift zone widened with a rate greater than 190 mm/d, whereas during the March episode that probably resulted in a thinner intrusion the maximum widening rate was only 50 mm/d. The data suggest that the magnitude of a subsidence episode is determined at least partly by the available excess magma pressure in the chamber. To explain the extensive growth of open fissures and normal faulting in the rift zone, it is necessary to assume that in addition to the intrusion of the main central dike at depth, many small dikes are intruded at shallow depths (less than 1 km). © 1983 by the American Geophysical Union. Received May 14, 1982; revised August 27, 1982; accepted October 22, 1982. The author wishes to thank Roger Bilham, Lucile M. Jones, and Terry Engelder for critically reviewing the manuscript. Pall Einarsson, Bryndis Brandsdottir, Axel Bjornsson, and Robert O. ... |
format |
Article in Journal/Newspaper |
author |
Hauksson, Egill |
spellingShingle |
Hauksson, Egill Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
author_facet |
Hauksson, Egill |
author_sort |
Hauksson, Egill |
title |
Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
title_short |
Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
title_full |
Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
title_fullStr |
Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
title_full_unstemmed |
Episodic rifting and volcanism at Krafla in north Iceland: Growth of large ground fissures along the plate boundary |
title_sort |
episodic rifting and volcanism at krafla in north iceland: growth of large ground fissures along the plate boundary |
publisher |
American Geophysical Union |
publishDate |
1983 |
url |
https://doi.org/10.1029/JB088iB01p00625 |
long_lat |
ENVELOPE(-16.747,-16.747,65.713,65.713) ENVELOPE(-55.215,-55.215,49.567,49.567) |
geographic |
Krafla New Ground |
geographic_facet |
Krafla New Ground |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Journal of Geophysical Research B, 88(B1), 625-636, (1983-01) |
op_relation |
https://doi.org/10.1029/JB088iB01p00625 oai:authors.library.caltech.edu:jg48g-fjk02 eprintid:38334 resolverid:CaltechAUTHORS:20130507-150226907 |
op_rights |
info:eu-repo/semantics/openAccess Other |
op_doi |
https://doi.org/10.1029/JB088iB01p00625 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
88 |
container_issue |
B1 |
container_start_page |
625 |
op_container_end_page |
636 |
_version_ |
1802645949144629248 |