Locking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010

Handle URI:
http://hdl.handle.net/10754/555763
Title:
Locking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010
Authors:
Metzger, Sabrina; Jonsson, Sigurjon ( 0000-0001-5378-7079 ) ; Geirsson, Halldór
Abstract:
Located at the northern shore of Iceland, the Tjörnes Fracture Zone (TFZ) is a 120 km offset in the mid-Atlantic Ridge that connects the offshore Kolbeinsey Ridge to the on-land Northern Volcanic Zone. This transform zone is seismically one of the most active areas in Iceland, exposing the population to a significant risk. However, the kinematics of the mostly offshore area with its complex tectonics have not been adequately resolved and the seismic potential of the two main transform structures within the TFZ, the Grímsey Oblique Rift (GOR) and the Húsavík Flatey Fault (HFF) in particular, is not well known. In summer 2006, we expanded the number of continuous GPS (CGPS) stations in the area from 4 to 14. The resulting GPS velocities after four years of data collection show that the TFZ accommodates the full plate motion as it is predicted by the MORVEL plate motion model. In addition, ENVISAT interferograms reveal a transient uplift signal at the nearby Theistareykir central volcano with a maximum line-of-sight uplift of 3 cm between summers of 2007 and 2008. We use a combination of an interseismic backslip and a Mogi model in a homogeneous, elastic half-space to describe the kinematics within the TFZ. With a non-linear optimization approach we fit the GPS observations and estimate the key model parameters and their uncertainties, which are (among others) the locking depth, the partition of the transform motion between the two transform structures within the TFZ and the slip rate on the HFF. We find a shallow locking depth of 6.3+1.7- 1.2 km and transform motion that is accommodated 34 ± 3 per cent by the HFF and 66 ± 3 per cent by the GOR, resulting in a slip velocity of 6.6 ± 0.6 mm yr-1 for the HFF. Assuming steady accumulation since the last two large M6.5 earthquakes in 1872 the seismic potential of the fault is equivalent to a Mw6.8 ± 0.1 event.
KAUST Department:
Physical Sciences and Engineering (PSE) Division
Citation:
Locking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010 2011, 187 (2):564 Geophysical Journal International
Journal:
Geophysical Journal International
Issue Date:
Nov-2011
DOI:
10.1111/j.1365-246X.2011.05176.x
Type:
Article
ISSN:
0956540X
Additional Links:
http://gji.oxfordjournals.org/cgi/doi/10.1111/j.1365-246X.2011.05176.x
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorMetzger, Sabrinaen
dc.contributor.authorJonsson, Sigurjonen
dc.contributor.authorGeirsson, Halldóren
dc.date.accessioned2015-05-26T07:06:43Zen
dc.date.available2015-05-26T07:06:43Zen
dc.date.issued2011-11en
dc.identifier.citationLocking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010 2011, 187 (2):564 Geophysical Journal Internationalen
dc.identifier.issn0956540Xen
dc.identifier.doi10.1111/j.1365-246X.2011.05176.xen
dc.identifier.urihttp://hdl.handle.net/10754/555763en
dc.description.abstractLocated at the northern shore of Iceland, the Tjörnes Fracture Zone (TFZ) is a 120 km offset in the mid-Atlantic Ridge that connects the offshore Kolbeinsey Ridge to the on-land Northern Volcanic Zone. This transform zone is seismically one of the most active areas in Iceland, exposing the population to a significant risk. However, the kinematics of the mostly offshore area with its complex tectonics have not been adequately resolved and the seismic potential of the two main transform structures within the TFZ, the Grímsey Oblique Rift (GOR) and the Húsavík Flatey Fault (HFF) in particular, is not well known. In summer 2006, we expanded the number of continuous GPS (CGPS) stations in the area from 4 to 14. The resulting GPS velocities after four years of data collection show that the TFZ accommodates the full plate motion as it is predicted by the MORVEL plate motion model. In addition, ENVISAT interferograms reveal a transient uplift signal at the nearby Theistareykir central volcano with a maximum line-of-sight uplift of 3 cm between summers of 2007 and 2008. We use a combination of an interseismic backslip and a Mogi model in a homogeneous, elastic half-space to describe the kinematics within the TFZ. With a non-linear optimization approach we fit the GPS observations and estimate the key model parameters and their uncertainties, which are (among others) the locking depth, the partition of the transform motion between the two transform structures within the TFZ and the slip rate on the HFF. We find a shallow locking depth of 6.3+1.7- 1.2 km and transform motion that is accommodated 34 ± 3 per cent by the HFF and 66 ± 3 per cent by the GOR, resulting in a slip velocity of 6.6 ± 0.6 mm yr-1 for the HFF. Assuming steady accumulation since the last two large M6.5 earthquakes in 1872 the seismic potential of the fault is equivalent to a Mw6.8 ± 0.1 event.en
dc.relation.urlhttp://gji.oxfordjournals.org/cgi/doi/10.1111/j.1365-246X.2011.05176.xen
dc.rightsArchived with thanks to Geophysical Journal International © The Authors Geophysical Journal International © 2011 RASen
dc.subjectTime series analysisen
dc.subjectSatellite geodesyen
dc.subjectRadar interferometryen
dc.subjectOceanic transform and fracture zone processesen
dc.subjectKinematics of crustal and mantle deformationen
dc.titleLocking depth and slip-rate of the Húsavík Flatey fault, North Iceland, derived from continuous GPS data 2006-2010en
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalGeophysical Journal Internationalen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionInstitute of Geophysics, ETH Zürich, Sonneggstrasse 5, 8092 Zürich, Switzerlanden
dc.contributor.institutionThe Pennsylvania State University, University Park, PA, USAen
dc.contributor.institutionIcelandic Meteorological Office (IMO), Reykjavík, Icelanden
kaust.authorJonsson, Sigurjonen
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