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Acquisition, processing and analysis of densely sampled P- and S-wave OBS-data on the mid-Norwegian Margin, NE Atlantic


This paper describes the processing and analysis of semi-local OBS-data shot along a 122 km profile in the Vøring Basin, NE Atlantic margin, using both a high-frequency/short shot-spacing and a low-frequency/long shot-spacing air-gun source. Spectral analysis of the data reveals that an important difference between the two sources used, is that the low-frequency source generates significantly more energy around 6 Hz. This higher content of very low frequencies allows detection of arrivals to larger offsets for the low-frequency source. For the nearest offsets (0–20 km) the high-frequency source is able to resolve some more details than the low-frequency source, as far as the shallow to intermediate sedimentary levels are concerned. This is mainly caused by the fact that the high-frequency source has a much sharper primary pulse and reduced bubble pulse compared to the low-frequency source. The data quality can be significantly enhanced by use of band-pass filtering, trace mixing, FK (velocity) filtering, minimum phase predictive deconvolution, as well as Radon filtering. Inspection of particle diagrams documents S-wave splitting, interpreted as microcracks aligned vertically in the sedimentary section by the present day (slightly compressive) stress-field.


  • Berg, E. W., L. Amundsen, A. Morton, R. Mjelde, H. Shimamura, H. Shiobara, T. Kanazawa, S. Kodaira, and J. P. Fjellanger, Three component OBS-data processing for lithology and fluid prediction in the mid-Norway margin, NE Atlantic, Earth Planets Space, 53, 75–89, 2001.

    Article  Google Scholar 

  • Bungum, H., A. Alsaker, L. B. Kvamme, and R. A. Hansen, Seismicity and seismotectonics of Norway and nearby continental shelf areas, J. Geophys. Res., 96(B2), 2,249–2,265, 1990.

    Article  Google Scholar 

  • Crampin, S., The scattering of S waves in the crust, Pure and Applied Geophysics, 132, 67–91, 1990.

    Article  Google Scholar 

  • Digranes, P., R. Mjelde, S. Kodaira, H. Shimamura, T. Kanazawa, H. Shiobara, and E. W. Berg, Modelling of shear waves in OBS data from the Vøring Basin (Northern Norway) by 2-D ray-tracing, Pure and Applied Geophysics, 4, 611–629, 1996.

    Article  Google Scholar 

  • Eldholm, O. and K. Grue, North Atlantic volcanic margins: Dimensions and production rates, J. Geophys. Res., 99, 2,955–2,968, 1994.

    Article  Google Scholar 

  • Kanazawa, T, Technical Description of TK92-type ocean bottom seismometer, in Investigation of the Central and Northern Part of the Vøring Basin by Use of Ocean Bottom Seismographs, R/V Håkon Mosby 22 Aug.–24 Sept. 1992, cruise report, Statoil report, Mjelde, R. etal, 1993.

  • Mjelde, R., M. A. Sellevoll, H. Shimamura, T. Iwasaki, and T. Kanazawa, A crustal study off Lofoten, N. Norway by use of 3-C ocean bottom seismographs, Tectonophys., 212, 269–288, 1992.

    Article  Google Scholar 

  • Mjelde, R., M. A. Sellevoll, H. Shimamura, T. Iwasaki, and T. Kanazawa, Crustal structure under Lofoten, N. Norway, from vertical incidence and wide-angle data, Geophys. J. Int., 114, 116–126, 1993.

    Article  Google Scholar 

  • Mjelde, R., M. A. Sellevoll, H. Shimamura, T. Iwasaki, and T. Kanazawa, S-wave anisotropy off Lofoten, Norway, indicative of fluids in the lower crust?, Geophys. J. Int., 120, 87–96, 1995.

    Article  Google Scholar 

  • Mjelde, R., S. Kodaira, H. Shimamura, T. Kanazawa, H. Shiobara, E. W. Berg, and O. Riise, Crustal structure of the central part of the Vøring basin, mid-Norway margin, from three-component ocean bottom seismographs, Tectonophys., 277, 235–257, 1997a.

    Article  Google Scholar 

  • Mjelde, R., S. Kodaira, P. Digranes, H. Shimamura, T. Kanazawa, H. Shiobara, and E. W. Berg, Comparison between a regional and semiregional crustal OBS-model in the Vøring basin, mid-Norway margin, Pure and Applied Geophysics, 149, 641–665, 1997b.

    Article  Google Scholar 

  • Mjelde, R., J. P. Fjellanger, P. Digranes, S. Kodaira, H. Shimamura, and H. Shiobara, Application of the single bubble air-gun technique for OBS-data acquisition across the Jan Mayen Ridge, North Atlantic, Marine Geophysical Researches, 19, 81–96, 1997c.

    Article  Google Scholar 

  • Mjelde, R., P. Digranes, H. Shimamura, H. Shiobara, S. Kodaira, H. Brekke, T. Egebjerg, N. Sørenes, and T. Thorbjørnsen, Crustal structure of the northern part of the Vøring Basin, mid-Norway margin, from wide-angle seismic and gravity data, Tectonophys., 293, 175–205, 1998.

    Article  Google Scholar 

  • Mjelde, R., J. P. Fjellanger, T. Raum, P. Digranes, S. Kodaira, A. Breivik, and H. Shimamura, Where do PS converions occur? Analysis of OBS-data from the NE Atlantic Margin, First Break, 20, 153–160, 2002.

    Article  Google Scholar 

  • Neidell, N. S., Land application of S waves, Geophysics: The Leading Edge of Exploration, 11, 32–44, 1985.

    Google Scholar 

  • Pajchel, J., H. B. Helle, and L. Frøyland, A 2-D seismic Modelling Package, User’s Manual, Geophys. Dep., Norsk Hydro Research Center, Bergen, 1989.

  • Samson, C, P. J. Barton, and J. Karwatowski, Imaging beneath an basaltic layer using densely sampled wide-angle OBS data, Geophysical Prospecting, 43, 509–528, 1995.

    Article  Google Scholar 

  • Sellevoll, M. A., H. Shimamura, A. Gidskehaug, and H. Johnsen, Seismiske undersøkelser av Lofoten marginen og refleksjonsseismiske test-målinger på Mohns Rygg, M/S Håkon Mosby, 29. juli-19. august 1988, Cruise report, IFJ, Univ. of Bergen, 1988.

  • Shiobara, H., A. Nakanishi, H. Shimamura, R. Mjelde, T. Kanazawa, and E. W. Berg, Precise positioning of Ocean Bottom Seismometer by Using Acoustic Transponder and CTD, Marine Geophysical Researches, 19, 199–209, 1997.

    Article  Google Scholar 

  • Trevorrow, M. V, T. Yamamoto, A. Turget, D. Goodman, and M. Badiey, Very low frequency ocean bottom ambient seismic noise and coupling on the shallow continental shelf, Marine Geophys. Res., 11, 129–152, 1989.

    Article  Google Scholar 

  • Webb, S. C. and C. S. Cox, Observations and modeling of seafloor microseisms, J. Geophys. Res., 91, 7343–7358, 1986.

    Article  Google Scholar 

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Correspondence to Rolf Mjelde.

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Mjelde, R., Timenes, T., Shimamura, H. et al. Acquisition, processing and analysis of densely sampled P- and S-wave OBS-data on the mid-Norwegian Margin, NE Atlantic. Earth Planet Sp 54, e1219–e1236 (2002).

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