Seismic structure modeling in the arctic ocean

Signals reflected and/or refracted in the seabed can be used to model its seismic structure. This has been done extensively in oil exploration and oceanographic research, and several inversion procedures now exist. Most of these methods require data from a dense sampling of source/receiver offsets. Operations in the Arctic Ocean do not permit these dense samplings because the pack ice limits the availability of open water. During the Fram II experiment in the Pole Abyssal Plain of the Eastern Arctic Ocean, extensive experiments in seismic reflection, seismic refraction and long range bottom interaction were conducted. Digital data on a 22 channel array were recorded. The seismic structure for the seabed below the Fram II ice camp were determined using velocity spectra and migration techniques that were developed to overcome the restrictions imposed by the ice pack. The paper discusses the Fram II seismic refraction profiling and bottom interaction experiments and the inversion methods used to determine the seismic structure.