1887
Volume 56 Number 1
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

We analysed vertical seismic profiling (VSP) data from two boreholes at Glyvursnes and Vestmanna on the island of Streymoy, Faroe Islands, to determine the magnitude and causes of seismic attenuation in sequences of basalt flows. The work is part of SeiFaBa, a major project integrating data from vertical and offset VSP, surface seismic surveys, core samples and wireline log data from the two boreholes. Values of effective seismic quality factor (Q) obtained at Glyvursnes and Vestmanna are sufficiently low to significantly degrade the quality of a surface reflection seismic image. This observation is consistent with results from other VSP experiments in the North Atlantic region. We demonstrate that the most likely cause of the low values of effective Q at Glyvursnes and Vestmanna is a combination of 1D scattering and intrinsic attenuation due to seismic wave‐induced fluid flow within pores and micro‐cracks. Tests involving 3D elastic wave numerical modelling with a hypothetical basalt model based on field observations, indicate that little scattering attenuation is caused by lateral variations in basalt structure.

Loading

Article metrics loading...

/content/journals/10.1111/j.1365-2478.2007.00665.x
2007-12-05
2024-04-26
Loading full text...

Full text loading...

References

  1. BondreN.R., DuraiswamiR.A. and DoleG.2004. A brief comparison of lava flows from the Deccan Volcanic Province and the Columbia‐Oregon Plateau Flood Basalts: Implications for models of flood basalt emplacement. Proceedings of the Indian Academy of Sciences (Earth and Planetary Sciences)113, 809–817.
    [Google Scholar]
  2. ChapmanM.2003. Frequency‐dependent anisotropy due to meso‐scale fractures in the presence of equant porosity. Geophysical Prospecting51, 369–379.
    [Google Scholar]
  3. ChristieP., GolliferI. and CowperD.2006. Borehole seismic studies of a volcanic succession from the Lopra‐1/1A borehole in the Faroe Islands, N.E. Atlantic. Geological Survey of Denmark and Greenland Bulletin9, 25–42.
    [Google Scholar]
  4. CrampinS.1994. The fracture criticality of crustal rocks. Geophysical Journal International118, 428–436.
    [Google Scholar]
  5. DvorkinJ., MavkoG. and NurA.1995. Squirt flow in fully saturated rocks. Geophysics60, 97–107.
    [Google Scholar]
  6. EllisD., BellB.R., JolleyD.W. and O'CallaghanM.2002. The stratigraphy, environment of eruption and age of the Faroes Lava Group, NE Atlantic ocean. In: The North Atlantic Igneous Province: Stratigraphy, Tectonic, Volcanic and Magmatic Processes (eds  D.W.Jolley and B.R.Bell ). Geological Society Special Publications 197, 253–269.
    [Google Scholar]
  7. FliednerM.M. and WhiteR.S.2001. Sub‐basalt imaging in the Faroe‐Shetland Basin with large offset data. First Break19, 247–252.
    [Google Scholar]
  8. GistG.A.1994. Fluid effects on velocity and attenuation in sandstones. Journal of the Acoustical Society of America96, 1158–1173.
    [Google Scholar]
  9. HolligerK.1996. Upper‐crustal seismic velocity heterogeneity as derived from a variety of P‐wave sonic logs. Geophysical Journal International125, 813–829.
    [Google Scholar]
  10. HolligerK.1997. Seismic scattering in the upper crystalline crust based on the evidence from sonic logs. Geophysical Journal International128, 65–72.
    [Google Scholar]
  11. HudsonJ.A.LiuE. and CrampinS.1996. The mechanical properties of materials with interconnected cracks and pores. Geophysical Journal International124, 105–112.
    [Google Scholar]
  12. JapsenP., AndersenC., AndersenH.L., AndersenM.S., BoldreelL.O., MavkoG., MohammedN.G., PedersenJ.M., PetersenU.K., RasmussenR., ShawF., SpringerN., WaagsteinR., WhiteR.S. and WorthingtonM.H.2005. Preliminary results from investigations of seismic and petrophysical properties of Faroes basalts in the SeiFaBa project. In: Petroleum Geology: North‐West Europe and Global Perspectives (eds  A.G.Dore and B.Vining ), pp. 1461–1470. Proceedings of the 6th Petroleum Geology Conference, Geological Society, London .
    [Google Scholar]
  13. JerramD.A.2002. Volcanology and facies architecture of flood basalts. In: Volcanic Rifted Margins (eds  M.A.Menzies , S.L.Klemperer , C.J.Ebinger and J.Baker ), Geological Society of America, Special Papers, 362, 121–135.
    [Google Scholar]
  14. KennettB.L.N.1979. Theoretical reflection seismograms for elastic media. Geophysical Prospecting27, 301–321.
    [Google Scholar]
  15. KranzR.L.1983. Microcracks in rocks: a review. Tectonophysics100, 449–480.
    [Google Scholar]
  16. LercheI. and MenkeW.1986. An inversion method for separating apparent and intrinsic attenuation in layered media. Geophysical Journal of the Royal Astronomical Society87, 333–347.
    [Google Scholar]
  17. LewisB.T.R. and JungH.1989. Attenuation of refracted seismic waves in young oceanic crust. Bulletin of the Seismological Society of America79, 1070–1088.
    [Google Scholar]
  18. LiuH.‐P., AndersonD.L. and KanamoriH.1976. Velocity dispersion due to anelasticity; implications for seismology and mantle composition. Geophysical Journal of the Royal Astronomical Society47, 41–58.
    [Google Scholar]
  19. MareshJ. and WhiteR.S.2005. Seeing through a glass, darkly: Strategies for imaging through basalt. First Break23, 27–32.
    [Google Scholar]
  20. MareshJ., WhiteR.S., HobbsR.W. and SmallwoodJ.R.2006. Seismic attenuation of Atlantic margin basalts: observations and modelling. Geophysics71, B211–B221. doi:DOI: 10.1190/1.2335875
    [Google Scholar]
  21. MartiniF. and BeanC.J.2002. Interface scattering versus body scattering in sub basalt imaging and application of prestack wave equation datuming. Geophysics67, 1593–1601.
    [Google Scholar]
  22. MavkoG. and JizbaD.1991. Estimating grain scale fluid effects on velocity dispersion in rocks. Geophysics56, 1940–1949.
    [Google Scholar]
  23. MenkeW.1983. A formula for the apparent attenuation of acoustic waves in randomly layered media. Geophysical Journal of the Royal Astronomical Society75, 541–544.
    [Google Scholar]
  24. MonetteL. and AndersonM.P.1994. Elastic and fracture properties of the two‐dimensional triangular and square lattices. Modelling and Simulation in Materials Science and Engineering2, 53–66.
    [Google Scholar]
  25. O'BrienG.S. and BeanC.J.2004. A 3D discrete numerical elastic lattice method for seismic wave propagation in heterogeneous media with topography. Geophysical Research Letters31, L14608. doi:DOI: 1029/2004GL020069
    [Google Scholar]
  26. PeacockS., McCannC., SothcottJ. and AstinT.R.1994. Seismic velocities in fractured rocks: An experimental verification of Hudson's theory. Geophysical Prospecting42, 27–80.
    [Google Scholar]
  27. PointerT., LiuE. and HudsonJ.A.2000. Seismic wave propagation in cracked porous Media. Geophysical Journal International142, 199–231.
    [Google Scholar]
  28. PrideS.R., HarrisJ.M., JohnsonD.L., MateevaA., NihelK.T., NowackR.L., RectorJ.W., SpetzlerH., WuR.‐S., YamomotoT., BerrymanJ.G. and FehlerM.2003. Permeability dependence of seismic amplitudes. The Leading Edge24, 518–525.
    [Google Scholar]
  29. PujolJ. and SmithsonS.1991. Seismic attenuation in volcanic rocks from VSP Experiments. Geophysics56, 1441–1455.
    [Google Scholar]
  30. PujolJ., FullerB.N. and SmithsonS.B.1989. Interpretation of a vertical seismic profile conducted in the Columbia Plateau basalts. Geophysics54, 1258–1266.
    [Google Scholar]
  31. RasmussenJ. and Noe‐NygaardA.1970. Geology of the Faroe Islands. Geological Survey of Denmark I. Series25, 1–142.
    [Google Scholar]
  32. RutledgeJ.T. and WinklerH.1989. Attenuation measurements from vertical seismic profile data: leg 104, site 642. Proceedings of the Ocean Drilling Program, Scientific Results 104, 965–972.
  33. SamsM.S., NeepJ.P., WorthingtonM.H. and KingM.S.1997. The measurement of velocity dispersion and frequency dependent intrinsic attenuation in sedimentary rocks. Geophysics62, 1456–1464.
    [Google Scholar]
  34. SelfS., KeszthelyiL. and ThordarsonTh.1998. The importance of pahoehoe. Annual Review of Earth and Planetary Sciences26, 81–110.
    [Google Scholar]
  35. ShawF.2006. Seismic properties of Faroe Island basalts . PhD thesis, Oxford University , UK .
  36. StainsbyS. D. and WorthingtonM.H.1985. Q estimation from vertical seismic profile data and anomalous variations in the central North Sea. Geophysics50, 615–626.
    [Google Scholar]
  37. SwiftS.A., LizarraldeD., StephenR.A. and HoskinsH., 1998. Seismic attenuation in the upper oceanic crust at Hole 504B. Journal of Geophysical Research103, 27,193–27,206.
    [Google Scholar]
  38. ThomsenL.1995. Elastic anisotropy due to aligned cracks in porous rock. Geophysical Prospecting43, 805–829.
    [Google Scholar]
  39. ToomeyA. and BeanC.J.2000. Numerical simulation of seismic waves using a discrete particle scheme. Geophysical Journal International141, 595–604.
    [Google Scholar]
  40. WaagsteinR.1988. Structure, composition and age of the Faroe basalt plateau. In: Early Tertiary volcanism and the opening of the North‐East Atlantic (eds  A.C.Morton and L.M.Parson ), pp. 225–238. Geological Society of London, Special Publications, 39.
    [Google Scholar]
  41. WhiteR.E.1992. The accuracy of estimating Q from seismic data. Geophysics57, 1508–1511.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/j.1365-2478.2007.00665.x
Loading
/content/journals/10.1111/j.1365-2478.2007.00665.x
Loading

Data & Media loading...

  • Article Type: Research Article

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error