3-D Seismic Tomographic Modelling of the North-Western Spitsbergen Area

Abstract:

Deep seismic sounding measurements were performed in the continent-ocean transition zone of the north-western Svalbard continental margin in 1976 - 1999 in an international co-operation. Seismic energy (airgun and TNT shots) was recorded by land (onshore) seismic stations, ocean bottom seismometers (OBS), and ocean bottom hydrophone systems (OBH). Data from archival and modern seismic profiles were altogether used for 3-D tomographic inversion using JIVE3D software. The modelling area was chosen to be a rectangle of 420 x 330 km (Fig.). The results are similar to the earlier 2-D modelling, supplemented by off-line information from the profiles and the SPITS permanent station, giving a 3-D image of the crustal structure and Moho interface shape. The continental crust thins to the west and north. A minimum depth of about 6 km to the Moho discontinuity was found east of the Molloy Deep and in the Knipovich Ridge. The Moho interface deepens to about 30 km beneath the continental crust of Spitsbergen.