Blar i forfatter "Ruud, Bent Ole"

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    • Characterization of seabed properties from Scholte waves acquired on floating ice on shallow water 

      Johansen, Tor Arne; Ruud, Bent Ole (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-01-09)
      Seismic surveying of the coastal areas in the Arctic is best facilitated during wintertime when the sea ice is land‐fast. This eases the logistics of the operation and assures that there is no damage made to the vulnerable tundra. Seismic experiments on floating ice on shallow water performed in a fjord in Svalbard in the Norwegian Arctic show prominent Scholte waves. The dispersion relation of ...

    • Measured sound levels in ice-covered shallow water caused by seismic shooting on top of and below floating ice, reviewed for possible impacts on true seals 

      Stemland, Helene Meling; Johansen, Tor Arne; Ruud, Bent Ole; Aniceto, Ana Sofia (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-01-01)
      Seismic surveying of the Arctic is important for several reasons, but also introduces some challenges. One is the concern that seismic data may affect the hearing of marine mammals living there, including true seals. We performed two seismic experiments on floating ice on Svalbard in the Norwegian Arctic in early March 2016 and late May 2017, just before and right after the ringed seal breeding ...

    • Passive seismic recording of cryoseisms in Adventdalen, Svalbard 

      Romeyn, Rowan; Hanssen, Alfred; Ruud, Bent Ole; Stemland, Helene Meling; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-20)
      A series of transient seismic events were discovered in passive seismic recordings from 2-D geophone arrays deployed at a frost polygon site in Adventdalen, Svalbard. These events contain a high proportion of surface wave energy and produce high-quality dispersion images using an apparent offset re-sorting and inter-trace delay minimisation technique to locate the seismic source, followed by ...

    • Potential use of time-lapse surface seismics for monitoring thawing of the terrestrial arctic 

      Stemland, Helene Meling; Johansen, Tor Arne; Ruud, Bent Ole (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-09)
      The terrestrial Arctic is warming rapidly, causing changes in the degree of freezing of the upper sediments, which the mechanical properties of unconsolidated sediments strongly depend upon. This study investigates the potential of using time-lapse surface seismics to monitor thawing of currently (partly) frozen ground utilizing synthetic and real seismic data. First, we construct a simple geological ...

    • Sea ice thickness from air-coupled flexural waves 

      Romeyn, Rowan; Hanssen, Alfred; Ruud, Bent Ole; Johansen, Tor Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-28)
      Air-coupled flexural waves (ACFWs) appear as wave trains of constant frequency that arrive in advance of the direct air wave from an impulsive source travelling over a floating ice sheet. The frequency of these waves varies with the flexural stiffness of the ice sheet, which is controlled by a combination of thickness and elastic properties. We develop a theoretical framework to understand these ...

    • Seismic on floating ice: data acquisition versus flexural wave noise 

      Johansen, Tor Arne; Ruud, Bent Ole; Tømmerbakke, Ronny; Jensen, Kristian (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-09)
      Geophysical surveying of the Arctic will become increasingly important in future prospecting and monitoring of the terrestrial and adjacent areas in this hemisphere. Seismic data acquired on floating ice are hampered with extensive noise due to ice vibrations related to highly dispersive ice flexural waves generated by the seismic source. Several experiments have been conducted on floating ice in ...