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Abstract

“This ocean-bottom seismometer deployment is part of the SEAMSTRESS project examining tectonic stress effects on Arctic methane seepage. The project is led by PI Andreia Plaza-Faverola at the Centre for Arctic Gas Hydrates, University of Tromsö, Norway. A total of 10 ocean bottom seismometers (OBS) were deployed on Vestnesa Ridge, a sediment drift body just north Knipovich Ridge at its intersection with the Molloy Transform fault (cruise CAGE-20-5). The aim of the experiment was to look for stress release along faults that control seepage sites on Vestnesa Ridge. The network consisted of 8 Lobster type broadband OBS from the German Instrument Pool for Amphibian Seismology (DEPAS) and 2 3C geophones provided by the University of Tromsö. Instruments were free-fall deployed and spaced by about 10 km. They recorded continuously at 100 Hz for 11 months between August 2020 and July 2021.Short, intersecting refraction profiles were shot across all OBS stations, such that OBS positions at the seafloor could be determined within 10 m (cruise CAGE-21-3). Clock drift in this experiment was nonlinear and skew values were only obtained for 6 of the stations. Skew-corrected station VSN01 served as reference station to obtain the clock drift of all other stations using noise cross-correlation and subsequently correct also for the thus determined nonlinearity of time drift. Waveform data are available from the GEOFON data centre, under network code Y9 and are embargoed until July 2025.