Formation and growth of normal faults at the divergent plate boundary in Iceland
ABSTRACT The divergent plate boundary in Iceland is characterized by 40–80 km long and 5–10 km wide swarms of tension fractures (∼10 2 m long) and normal faults (∼10 3 m long). The upper part of the crust is mainly composed of lava flows, with abundant columnar joints that are mostly perpendicular t...
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crwiley:10.1111/j.1365-3121.1992.tb00582.x 2024-09-15T18:13:30+00:00 Formation and growth of normal faults at the divergent plate boundary in Iceland Gudmundsson, Agust 1992 http://dx.doi.org/10.1111/j.1365-3121.1992.tb00582.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3121.1992.tb00582.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3121.1992.tb00582.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Terra Nova volume 4, issue 4, page 464-471 ISSN 0954-4879 1365-3121 journal-article 1992 crwiley https://doi.org/10.1111/j.1365-3121.1992.tb00582.x 2024-08-09T04:29:30Z ABSTRACT The divergent plate boundary in Iceland is characterized by 40–80 km long and 5–10 km wide swarms of tension fractures (∼10 2 m long) and normal faults (∼10 3 m long). The upper part of the crust is mainly composed of lava flows, with abundant columnar joints that are mostly perpendicular to the lava contacts. The lava flows are horizontal at the surface of the rift zone but become tilted at the rate of 1° for every 150 m depth in the crust. At the surface of the rift zone the joints are vertical and parallel to the vertical principal stress. Because of tilting of the lava pile, the columnar joints become oblique to this stress, hence becoming potential shear fractures, and form echelon sets at greater depths in the crust. Theoretical considerations suggest that normal faults start to nucleate on sets of en echelon columnar joints and/or large‐scale tension fractures at crustal depths of 0.5–1.5 km. The width (depth) must be the smallest (controlling) dimension of many faults. Nevertheless, there is a positive linear relation (r = 0.91) between maximum throw and length of the Holocene faults. If the faults grow as self‐similar structures, the throw‐length relationship can be explained by a similar relation between fault length and width. Article in Journal/Newspaper Iceland Wiley Online Library Terra Nova 4 4 464 471 |
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Wiley Online Library |
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crwiley |
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English |
description |
ABSTRACT The divergent plate boundary in Iceland is characterized by 40–80 km long and 5–10 km wide swarms of tension fractures (∼10 2 m long) and normal faults (∼10 3 m long). The upper part of the crust is mainly composed of lava flows, with abundant columnar joints that are mostly perpendicular to the lava contacts. The lava flows are horizontal at the surface of the rift zone but become tilted at the rate of 1° for every 150 m depth in the crust. At the surface of the rift zone the joints are vertical and parallel to the vertical principal stress. Because of tilting of the lava pile, the columnar joints become oblique to this stress, hence becoming potential shear fractures, and form echelon sets at greater depths in the crust. Theoretical considerations suggest that normal faults start to nucleate on sets of en echelon columnar joints and/or large‐scale tension fractures at crustal depths of 0.5–1.5 km. The width (depth) must be the smallest (controlling) dimension of many faults. Nevertheless, there is a positive linear relation (r = 0.91) between maximum throw and length of the Holocene faults. If the faults grow as self‐similar structures, the throw‐length relationship can be explained by a similar relation between fault length and width. |
format |
Article in Journal/Newspaper |
author |
Gudmundsson, Agust |
spellingShingle |
Gudmundsson, Agust Formation and growth of normal faults at the divergent plate boundary in Iceland |
author_facet |
Gudmundsson, Agust |
author_sort |
Gudmundsson, Agust |
title |
Formation and growth of normal faults at the divergent plate boundary in Iceland |
title_short |
Formation and growth of normal faults at the divergent plate boundary in Iceland |
title_full |
Formation and growth of normal faults at the divergent plate boundary in Iceland |
title_fullStr |
Formation and growth of normal faults at the divergent plate boundary in Iceland |
title_full_unstemmed |
Formation and growth of normal faults at the divergent plate boundary in Iceland |
title_sort |
formation and growth of normal faults at the divergent plate boundary in iceland |
publisher |
Wiley |
publishDate |
1992 |
url |
http://dx.doi.org/10.1111/j.1365-3121.1992.tb00582.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3121.1992.tb00582.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3121.1992.tb00582.x |
genre |
Iceland |
genre_facet |
Iceland |
op_source |
Terra Nova volume 4, issue 4, page 464-471 ISSN 0954-4879 1365-3121 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1365-3121.1992.tb00582.x |
container_title |
Terra Nova |
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4 |
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4 |
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464 |
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471 |
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1810451270660521984 |