Submarine Slides At Finneidfjord (Norway): Geophysical Investigations

On June 20th, 1996, a submarine land failure in a fjord near the village of Finneidfjord (Northern Norway) developed into a retrogressive quick clay slide encroaching 100-150 m inland, resulting in the loss of life and significant material damage. Reports in the aftermath of the slide concluded that build up of excess pore pressure may have been the main reason for the slide, though other causes are invoked too. The geological settings at this location involve many of the processes typical for large offshore slides. As the fjord is sheltered and accessible, this location is ideal as a field laboratory for studying submarine slide hazards. Such a project for evaluating instrumentation and site investigation techniques for studying submarine slope stability was initiated in 2004 by the International Centre for Geohazards (ICG, Oslo). Initial field campaigns since 1997 have consisted of sediment coring, VHR seismic surveys, and the deployment of long term in situ instrumentation. A larger campaign is planned in 2008, including shear-wave acquisition, and, to support that campaign with land data, several geophysical investigations were carried out onshore in July 2007 in cooperation with the University of Strasbourg. The field studies have included several students to train them in field practice. Seismic, GPR and<br>resistivity investigations were all carried out, and preliminary results are presented.