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Revealing the deepe...
Revealing the deeper structure of the end-glacial Pärvie fault system in northern Sweden by seismic reflection profiling
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- Ahmadi, Omid (författare)
- Uppsala universitet,Geofysik
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- Juhlin, Christopher (författare)
- Uppsala universitet,Geofysik
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- Ask, Maria (författare)
- Luleå tekniska universitet,Geovetenskap och miljöteknik,Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology
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visa fler...
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- Lund, Björn (författare)
- Uppsala universitet,Geofysik
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(creator_code:org_t)
- 2015-06-03
- 2015
- Engelska.
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Ingår i: Solid Earth Discussions. - : Copernicus GmbH. - 1869-9537 .- 1869-9529 .- 1869-9510. ; 6:2, s. 537-563
- Relaterad länk:
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https://doi.org/10.5...
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visa fler...
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https://www.solid-ea...
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https://uu.diva-port... (primary) (Raw object)
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https://urn.kb.se/re...
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https://doi.org/10.5...
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https://urn.kb.se/re...
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visa färre...
Abstract
Ämnesord
Stäng
- Fault scarps that extend up to 155 km and have offsets of tens of meters at the surface are present in the northern parts of Finland, Norway and Sweden. These fault scarps are inferred to have formed during earthquakes with magnitudes up to 8 at the time of the last deglaciation. The Pärvie fault system represents the largest earthquake so far documented in northern Scandinavia, both in terms of its length and its calculated magnitude. It is also the longest known glacially induced fault in the world. Present-day microearthquakes occur along the length of the fault scarp on the eastern side of the scarp, in general agreement with an east dipping main fault. In the central section of the fault, where there is a number of subsidiary faults east of the main fault, it has been unclear how the earthquakes relate to the faults mapped at the surface. A seismic profile across the Pärvie Fault system acquired in 2007, with a mechanical hammer as a source, showed a good correlation between the surface mapped faults and moderate to steeply dipping reflectors. The most pronounced reflector could be mapped to about 3 km depth. In an attempt to map the fault system to deeper levels, a new 22 km long 2-D seismic profile which followed the 2007 line was acquired in June 2014. For deeper penetration an explosive source with a maximum charge size of 8.34 kg in 20 m deep shot holes was used. Reflectors can now be traced to deeper levels with the main 65◦ east dipping fault interpreted as a weakly reflective structure. As in the previous profile, there is a pronounced strongly reflective 60◦ west dipping structure present to the east of the main fault that can now be mapped to about 8 km depth. Extrapolations of the main and subsidiary faults converge at a depth of about 11.5 km where current earthquake activity is concentrated, suggesting their intersection has created favorable conditions for seismic stress release. Based on the present and previous seismic reflection data, potential locations for future boreholes for drilling into the fault system are proposed.
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geofysik (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geophysics (hsv//eng)
Nyckelord
- Applied Geology
- Tillämpad geologi
- Framtidens gruvor (FOI)
- Future mining (AERI)
- Geofysik med inriktning mot fasta jordens fysik
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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