• Marine seismics with a pulsed combustion source and Pseudo Noise codes 

      Askeland, Bjørn; Hobæk, Halvor; Mjelde, Rolf (Peer reviewed; Journal article, 2007-03)
      There has been an ongoing debate for years of how dangerous seismic surveys are with respect to marine life. Marine seismics is today dominated by airgun technology, where high energy is generated by a release of compressed ...
    • Measured and modeled acoustic propagation underneath the rough Arctic sea-ice 

      Hope, Gaute; Sagen, Hanne; Storheim, Espen; Hobæk, Halvor; Freitag, Lee (Peer reviewed; Journal article, 2017-09)
      A characteristic surface duct beneath the sea-ice in the Marginal Ice Zone causes acoustic waves to be trapped and continuously interact with the sea-ice. The reflectivity of the sea-ice depends on the thickness, the elastic ...
    • Scattering from spheres and cylinders - revisited 

      Hobæk, Halvor; Nesse, Tonje Lexau (Conference object, 2006)
      Backscattering of sound from elastic spheres is commonly applied for calibration of acoustic systems. Measurements on the "form function" of various tungsten carbide spheres turned out not to match simulations based on ...
    • A seismic field test with a Low level Acoustic Combustion Source and Pseudo Noise codes 

      Askeland, Bjørn; Ruud, Bent; Hobæk, Halvor; Mjelde, Rolf (2007-01-20)
      The Low level Acoustic Combustion Source (LACS) is a new type of pulsed underwater acoustic source with an output level of 0.5-1.0 barm peak to peak. The source is based on a combustion engine and intended for shallow ...