Ocean bottom seismometer experiment on the Beaufort shelf and slope region conducted during Expedition ARA04C on the IBRV Araon

Abstract

Expedition ARA04C (conducted from September 10 - September 26, 2013 in Canadian waters) on the Korean icebreaker IBRV Araon was laid out to investigate the Beaufort Sea shelf and slope region and collect geo-scientific data for various aspects relevant to the GSC's mandated regional geo-hazard assessment of the offshore Beaufort region. A critical element of the geohazards is the distribution of permafrost across the submerged shelf. To address this question a set of six Ocean Bottom Seismometers (OBS) were deployed in a grid pattern across the near shelf-edge zone, and a set of three OBS was used in a second deployment along a central shelfcrossing north-east to south-west oriented line. Initial data processing was carried out, which is required for any follow-up detailed velocity analysis. The processing included definition of exact shot times, geometry calculation, OBS position re-location, and OBS orientation analysis. A preliminary analysis of the hydrophone and vertical-component data from the OBS stations reveals a P-wave-velocity structure with values ranging from 1800 m/s to over 4000 m/s indicative of wide-spread ice-bearing sediments. This open-file report also contains the digital OBS data for all stations in standard SEGY format, together with the required raw and processed geometry information.