S. T. Detweiler

Three-dimensional model for the crust and upper mantle in the Barents Sea region

The Barents Sea and its surroundings is an epicontinental region which previously has been difficult to access, partly because of its remote Arctic location (Figure 1) and partly because the region has been politically sensitive. Now, however, this region, and in particular its western parts, has been very well surveyed with a variety of geophysical studies, motivated in part by exploration for hydrocarbon resources. Since this region is interesting geophysically as well as for seismic verification, a major study [Bungum et al., 2004] was initiated in 2003 to develop a three-dimensional (3-D) seismic velocity model for the crust and upper mantle, using a grid density of 50 km. This study, in cooperation between NORSAR, the University of Oslo (UiO),and the U.S.Geological Survey (USGS), has led to the construction of a higher-resolution, regional lithospheric model based on a comprehensive compilation of available seismological and geophysical data. Following the methodology employed in making the global crustal model CRUST5.1 [Mooney et al., 1998], the new model consists of five crustal layers: soft and hard sediments, and crystalline upper, middle, and lower crust. Both P- and S-wave velocities and densities are specified in each layer. In addition, the density and seismic velocity structure of the uppermost mantle, essential for Pn and Sn travel time modeling, are included.