Fault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia

Handle URI:
http://hdl.handle.net/10754/582715
Title:
Fault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia
Authors:
Trippanera, D.; Acocella, V.; Ruch, Joel; Abebe, B.
Abstract:
Recent studies highlight the importance of annual-scale dike-induced rifting episodes in developing normal faults and graben along the active axis of magmatic divergent plate boundaries (MDPB). However, the longer-term (102-105 years) role of diking on the cumulative surface deformation and evolution of MDPB is not yet well understood. To better understand the longer-term normal faults and graben along the axis of MDPB, we analyze fissure swarms in Iceland and Ethiopia. We first focus on the simplest case of immature fissure swarms, with single dike-fed eruptive fissures; these consist of a <1 km wide graben bordered by normal faults with displacement up to a few meters, consistent with theoretical models and geodetic data. A similar structural pattern is found, with asymmetric and multiple graben, within wider mature fissure swarms, formed by several dike-fed eruptive fissures. We then consider the lateral termination of normal faults along these graben, to detect their upward or downward propagation. Most faults terminate as open fractures on flat surface, suggesting downward fault propagation; this is consistent with recent experiments showing dike-induced normal faults propagating downward from the surface. However, some normal faults also terminate as open fractures on monoclines, which resemble fault propagation folds; this suggests upward propagation of reactivated buried faults, promoted by diking. These results suggest that fault growth and graben development, as well as the longer-term evolution of the axis of MDPB, may be explained only through dike emplacement and that any amagmatic faulting is not necessary.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Fault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia 2015:n/a Tectonics
Publisher:
Wiley-Blackwell
Journal:
Tectonics
Issue Date:
8-Oct-2015
DOI:
10.1002/2015TC003991
Type:
Article
ISSN:
02787407
Additional Links:
http://doi.wiley.com/10.1002/2015TC003991
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorTrippanera, D.en
dc.contributor.authorAcocella, V.en
dc.contributor.authorRuch, Joelen
dc.contributor.authorAbebe, B.en
dc.date.accessioned2015-11-25T13:59:29Zen
dc.date.available2015-11-25T13:59:29Zen
dc.date.issued2015-10-08en
dc.identifier.citationFault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia 2015:n/a Tectonicsen
dc.identifier.issn02787407en
dc.identifier.doi10.1002/2015TC003991en
dc.identifier.urihttp://hdl.handle.net/10754/582715en
dc.description.abstractRecent studies highlight the importance of annual-scale dike-induced rifting episodes in developing normal faults and graben along the active axis of magmatic divergent plate boundaries (MDPB). However, the longer-term (102-105 years) role of diking on the cumulative surface deformation and evolution of MDPB is not yet well understood. To better understand the longer-term normal faults and graben along the axis of MDPB, we analyze fissure swarms in Iceland and Ethiopia. We first focus on the simplest case of immature fissure swarms, with single dike-fed eruptive fissures; these consist of a <1 km wide graben bordered by normal faults with displacement up to a few meters, consistent with theoretical models and geodetic data. A similar structural pattern is found, with asymmetric and multiple graben, within wider mature fissure swarms, formed by several dike-fed eruptive fissures. We then consider the lateral termination of normal faults along these graben, to detect their upward or downward propagation. Most faults terminate as open fractures on flat surface, suggesting downward fault propagation; this is consistent with recent experiments showing dike-induced normal faults propagating downward from the surface. However, some normal faults also terminate as open fractures on monoclines, which resemble fault propagation folds; this suggests upward propagation of reactivated buried faults, promoted by diking. These results suggest that fault growth and graben development, as well as the longer-term evolution of the axis of MDPB, may be explained only through dike emplacement and that any amagmatic faulting is not necessary.en
dc.language.isoenen
dc.publisherWiley-Blackwellen
dc.relation.urlhttp://doi.wiley.com/10.1002/2015TC003991en
dc.rightsThis is the peer reviewed version of the following article: Trippanera, D., V. Acocella, J. Ruch, and B. Abebe (2015), Fault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopia, Tectonics, 34, doi:10.1002/2015TC003991., which has been published in final form at http://doi.wiley.com/10.1002/2015TC003991. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.en
dc.titleFault and graben growth along active magmatic divergent plate boundaries in Iceland and Ethiopiaen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalTectonicsen
dc.eprint.versionPost-printen
dc.contributor.institutionRoma Tre University; Rome Italyen
dc.contributor.institutionUniversity of Addis Ababa; Addis Ababa Ethiopiaen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorRuch, Joelen
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