Three-dimensional seismic model of crustal structure in Southern Norway
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Three-dimensional seismic model of crustal structure in Southern Norway. / Loidl, B.; Behm, M.; Thybo, Hans; Stratford, Wanda R.
I: Geophysical Journal International, Bind 196, Nr. 3, 2014, s. 1643-1656.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Three-dimensional seismic model of crustal structure in Southern Norway
AU - Loidl, B.
AU - Behm, M.
AU - Thybo, Hans
AU - Stratford, Wanda R.
PY - 2014
Y1 - 2014
N2 - New insights in crustal structure in southern Norway are given by combining stacking techniques and traveltime tomography of 3-D wide-angle reflection/refraction data. The Magnus Rex crustal scale wide-angle refraction/reflection data set in Southern Norway covers an area of 400 km × 430 km where 716 receivers on three profiles recorded seismic waves from 26 explosive sources. Previous data analysis focused on 2-D interpretation along the profiles. Here we extract additional P-wave velocity information by inverting inline and cross-line data simultaneously. We combine stacking routines, traveltime tomography, and interpolation algorithms to the high quality inline and cross-line data. A smooth 3-D crustal velocity model is inverted from traveltimes of diving Pg waves with similar results for two initial models. Initial models include a 1-D average model and an interpolated 3-D model based on robust, local 1-D velocity-depth functions derived from CMP-sorted and stacked records. The depth to Moho is determined from reflected waves (PmP) by traditional exploration seismology processing routines (CMP sorting, NMO correction, stacking, depth conversion). We find that this combination of stacking methods and traveltime tomography is well suited to exploit sparse 3-D wide-angle data. The results along the profiles are similar to the earlier 2-D models and the 3-D velocity model shows little lateral variation. The crust in SW Norway is generally 35–40 km thick and has relatively low average velocity, as it lacks the characteristic high-velocity lower crust, otherwise observed in the Baltic Shield. However, the Oslo Graben is characterized by high crustal velocities and a slightly elevated Moho. Our results suggest that this crustal structure continues towards the north along the strike of the graben.
AB - New insights in crustal structure in southern Norway are given by combining stacking techniques and traveltime tomography of 3-D wide-angle reflection/refraction data. The Magnus Rex crustal scale wide-angle refraction/reflection data set in Southern Norway covers an area of 400 km × 430 km where 716 receivers on three profiles recorded seismic waves from 26 explosive sources. Previous data analysis focused on 2-D interpretation along the profiles. Here we extract additional P-wave velocity information by inverting inline and cross-line data simultaneously. We combine stacking routines, traveltime tomography, and interpolation algorithms to the high quality inline and cross-line data. A smooth 3-D crustal velocity model is inverted from traveltimes of diving Pg waves with similar results for two initial models. Initial models include a 1-D average model and an interpolated 3-D model based on robust, local 1-D velocity-depth functions derived from CMP-sorted and stacked records. The depth to Moho is determined from reflected waves (PmP) by traditional exploration seismology processing routines (CMP sorting, NMO correction, stacking, depth conversion). We find that this combination of stacking methods and traveltime tomography is well suited to exploit sparse 3-D wide-angle data. The results along the profiles are similar to the earlier 2-D models and the 3-D velocity model shows little lateral variation. The crust in SW Norway is generally 35–40 km thick and has relatively low average velocity, as it lacks the characteristic high-velocity lower crust, otherwise observed in the Baltic Shield. However, the Oslo Graben is characterized by high crustal velocities and a slightly elevated Moho. Our results suggest that this crustal structure continues towards the north along the strike of the graben.
KW - Composition of the continental crust
KW - Controlled source seismology
KW - Seismic tomography
KW - Continental tectonics: extensional
KW - Europe
U2 - 10.1093/gji/ggt471
DO - 10.1093/gji/ggt471
M3 - Journal article
VL - 196
SP - 1643
EP - 1656
JO - Geophysical Journal International
JF - Geophysical Journal International
SN - 0956-540X
IS - 3
ER -
ID: 132044106