A 3D model (BARENTS3D) for the seismic velocity and density structure of the crust and upper mantle in the greater Barents Sea Region has been developed by a Norwegian-US team as a composite of two separate models, one for the crust (BARENTS50) and one for the upper mantle (BARMOD).
For the crustal model a large amount of 1D seismic velocity profiles sampled from continuous 2D seismic wide-angle transects were used, and deep-seismic reflection data in the western Barents Sea were additionally employed for density modeling and for density-to-velocity conversion. Area-wide depth-to-basement data were used to adjust the crystalline crustal thickness where needed. The 3D crustal velocity model (BARENTS50; Ritzmann et al., 2007) is based on an equidistant grid with a node spacing of 50 km, and for each node point two sedimentary and three crystalline layers have been defined in terms of their depths and physical properties.
The upper mantle model (BARMOD; Levshin et al., 2007) is based on a large dataset of predominantly new surface-wave observations from more than 150 local and regional events with travel paths through the greater Barents Sea region. These observations of group-velocities were first inverted for 2D group-velocity maps and subsequently for a 3D S-wave velocity model with a nominal resolution of 1 by 1 degree. Applying standard conversion relations, the model contains also P-wave velocities and densities.
In a final step the crustal model was combined with the surface-wave inversion mantle structure sampled laterally at 50 km, resulting in a complete 3D hybrid velocity model BARENTS3D that provides a significantly better resolution and accuracy than previously published models.
The BARENTS3D model should be cited by NORSART(2006): BARENTS3D, http://www.norsar.no/seismology/barents3d/ accompanied by:
Ritzmann, O., N. Maercklin, J.I. Faleide, H. Bungum, W.D. Mooney and S.T. Detweiler (2007): A 3D geophysical model for the crust in the greater Barents Sea region: Database compilation, model construction and basement characterisation. Geoph. J. Int., 170, 417-435, doi: 10.1111/j.1365-246X.2007.03337.x
Levshin, A., J. Schweitzer, Ch. Weidle, N. Shapiro and M. Ritzwoller (2007): Surface wave tomography of the Barents Sea and surrounding regions. Geoph. J. Int., 170, 441-459, doi: 10.1111/j.1365-246X.2006.03285.x
This study was funded by the U.S. Department of Energy through the National Nuclear Security Administration, Contract Nos. DE-FC52-03NA99508, DE-FC52-03NA99509 and DE-FC52-03NA99531. The crustal study was additionally supported by the University of Oslo and the surface-wave tomography work was additionally supported by NORSAR, the University of Oslo, the University of Colorado, and IPG Paris.
BARENTS3D is a hybrid model based on the crustal model BARENTS50 and the upper mantle model BARMOD. The currently available release of BARENTS3D is Version1.1 as of Jan. 31, 2006.
- Crustal model BARENTS50
- Upper mantle model BARMOD
- Combined BARENTS3D model
- Format description for the model files