Seismic structure of Iceland along RRISP-profile I
Article Sidebar
Published:
Jan 24, 1980
Keywords:
Iceland,
Reykjanes Ridge,
Deep seismic sounding,
Crust,
Lithosphere,
Asthenosphere,
Anomalous mantle,
Partial fusion
Volumes
Vols. 1-18 (1924-1944), ISSN 0044-2801
Main Article Content
Abstract
As part of the RRISP 77 combined land-sea refraction seismic experiment, observations were carried out on Iceland itself with special emphasis on resolving the deep structure beneath Iceland and its transition towards the eastern flank of Reykjanes Ridge. The data, interpretational procedures, and results for the land part are described in this paper. A structural model of Iceland is presented which is characterized by a generalized two-layered crust of variable thickness underlain by anomalous mantle with P-wave velocities of 7.0 km/s at the base of the crust increasing to 7.4 km/s at 30 km depth. Two regions of relatively low velocity have been identified in the lower crust, possibly indicating zones of high melt concentration. A normal P- to S-wave velocity ratio of 1.76 is found within the crust, whereas this ratio reaches unusually high values of up to 2.2 in the anomalous mantle. From this and the P-wave velocity distribution the amount of partial melt is calculated. The melt content is highest (17%-23%) at the top of the mantle and decreases with increasing depth indicating differentiation processes in the upper mantle. The anomalous mantle is confined to Iceland and a sharp transition exists in the area of the shelf edge where normal oceanic lithosphere replaces the updoming asthenosphere.
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Article Details
How to Cite
Gebrande, H., Miller, H., & Einarsson, P. (1980). Seismic structure of Iceland along RRISP-profile I. Journal of Geophysics, 47(1), 239-249. Retrieved from https://journal.geophysicsjournal.com/JofG/article/view/72
Section
References
Anderson, D.L., Sammis, C., Jordan, T. (1972) Composition of the mantle and core. In: The Nature of the Solid Earth, E.C. Robertson et al. (Eds).: pp. 41-66. New York, McGraw-Hill
Angenheister, G., Gebrande, H., Miller, H., Weigel, W., Goldflam, P., Jacoby, W., Palmason, G., Bjiirnsson, S., Einarsson, P., Zverev, S., Loncarevic, B., Solomon, S. (1979) First results from the Reykjanes Ridge Iceland Seismic Project 1977. Nature 279:56-60
Bath, M. (1960) Crustal structure of Iceland, J. Geophys. Res. 65:1793-1807
Beblo, M., Bjornsson, A. (1978) Magnetotelluric investigation of the lower crust and upper mantle beneath Iceland. J. Geophys. 45:1-16
Beblo, M., Bjornsson, A. (1980) A model of electrical resistivity beneath NE-Iceland; Correlation with temperature. J. Geophys. 47:184-190
Beloussov, V.V., Milanovskiy, Y.Y. (1976) On the tectonic and tectonic position of Iceland. Soc. Sci. Islandica, Greinar 5:96-120
Bemmelen, van R.W. (1972) Geodynamic models; an evaluation and a synthesis. Amsterdam, Elsevier
Birch, F. (1969) Density and composition of the upper mantle: first approximation as an olivine layer. In: The Earth's crust and upper mantle, P.J., Hart, (Ed.): pp. 18-36. Washington: Am. Geophys Union
Bott, M.H.P. (1965) The upper mantle beneath Iceland. Geophys. J. 9:275-277
Bott, M.H.P. (1974) Deep structure, evolution and origin of the Icelandic transverse ridge. In: Geodynamics of Iceland and the North Atlantic Area, L. Kristiansson (Ed.): pp. 33-47. Dordrecht, Reidel
Bott, M.H.P., Gunnarsson, K. (1980) Crustal structure of the IcelandFaeroe Ridge. J. Geophys. 47:221-227
Bullard, E. C., Everett, J.E., Smith, A. G. (1965) The fit of the continents around the Atlantic. Philos. Trans. R. Soc. London, Ser. A: 258:41-51
Christensen, N.I. (1978) Ophiolites, seismic velocities and oceanic crustal structure. Tectonophysics 47:131-157
Christensen, N.I., Salisbury, M.H. (1976) Structure and constitution of the lower oceanic crust. Rev. Geophys. Space Phys. 13:57-86
Einarsson, P. (1979) Travel times recorded at Icelandic seismograph stations during the Reykjanes Ridge Iceland Seismic Project (RRISP). Pub!. Sci. Inst. Univ. Iceland RH-79-10
Einarsson, T. (1954) A survey of gravity in Iceland. Soc. Sci. Islandica 30
Fl6venz, O.G. (1980) Seismic structure of the Icelandic crust above layer three and the relation between body wave velocity and the alteration of the basaltic crust. J. Geophys. 47:211-220
Francis, T.J.G. (1969) Upper mantle structure along the axis of the Mid-Atlantic Ridge near Iceland. Geophys. J.R. Astron. Soc. 17:507-520
Gebrande, H. (1976) A seismic-ray tracing method for two-dimensional inhomogenous media. In: Explosion seimology in central Europe, P. Giese, C. Prodehl, A. Stein (Eds.): 162-167. Berlin, Heidelberg, New York; Springer
Goldflam, P., Weigel, W., Loncarevic, B. (1980) Seismic structure along RRISP - Profile I on the south-east flank of the Reykjanes Ridge. J. Geophys. 47:250-260
Green, D. H., Ringwood, A. E. (1963) Mineral assemblages in a model mantle composition. J. Geophys. Res. 68:937-945
Hashin, Z. (1966) Elasticity of ceramic systems. In: Ceramic microstructures, R.M. Fulrath, J.A. Pask (Eds.): pp. 313-341. New York, London, Sydney, Wiley
Hermance, J.F., Grillot, L.R. (1974) Constraints on temperatures beneath Iceland from magnetotelluric data. Phys. Earth. Planet. Inter. 8:1-12
Kroenke, L.W., Manghnani, M.H., Rai, C.S., Fryer, P., Ramananan-toandro, R. (1976) Elastic properties of selected ophiolitic rocks from Papua New Guinea: nature and composition of the oceanic lower crust and upper mantle. In: The Geophysics of the Pacific Ocean Basin and its Margin, G.H. Sutton, M.H. Manghnani, R. Moberly (Eds.): pp. 407-421. Washington: Am. Geophys. Union
Laughton, A.S. (1971) South Labrador Sea and the evolution of the North Atlantic. Nature 232:612-617
Long, R.E., Mitchell, M.G. (1970) Teleseismic P-wave delay time in Iceland. Geophys. J.R. Astron. Soc. 20:41-48
Palmason, G. (1971) Crustal structure of Iceland from explosion seismology. Reykjavik: Soc. Sci. Islandica 40
Palmason, G., Saemundsson, K. (1974) Iceland in relation to the MidAtlantic Ridge. Annu. Rev. Earth Planet. Sci. 2:25-50
Peterson, J.J., Fox, P.J., Schreiber, E. (1974) Newfoundland ophiolites and the geology of the oceanic layer. Nature 247:194-196
Rober, K.R., Thyssen, F. (1978) Messung der Schallgeschwindigkeit beim Ubergang fest - fliissig. DFG Kolloquium, Geowissenschaftliche Hochdruckforschung, Bad Honnef pp. 13-14
RRISP Working Group (1980) Reykjanes Ridge Iceland seismic experiment. J. Geophys. 47:228-238
Stefansson, R. (1966) Methods of focal mechanism studies with application on two Atlantic earthquakes. Tectonophysics 3:210-243
Tryggvason, E. (1962) Crustal structure of the Iceland region from dispersion of surface waves. Bull. Seismol. Soc. Am. 52:359-388
Tryggvason, E. (1964) Arrival times of P-waves and upper mantle structure. Bull. Seismol. Soc. Am. 54:727-736
Walsh, J.B. (1968) Attenuation in partially melted material. J. Geophys. Res. 73:2209-2216
Walsh, J.B. (1969) New analysis of attenuation in partially melted rock. J. Geophys. Res. 74:4333-4337
Wielandt, E. (1972) Anregung seismischer Wellen durch Unterwasserexplosionen. Diss., Univ. Karlsruhe, 90 pp.
Zverev, S.M., Kosminskaya, I.P., Krasilschikova, G.A., Mikhota, G. G. (1976) The crustal structure of Iceland and of the Iceland-Faeroe-Shetland region. Soc. Sci. Islandica, Greinar 5:72-95
Angenheister, G., Gebrande, H., Miller, H., Weigel, W., Goldflam, P., Jacoby, W., Palmason, G., Bjiirnsson, S., Einarsson, P., Zverev, S., Loncarevic, B., Solomon, S. (1979) First results from the Reykjanes Ridge Iceland Seismic Project 1977. Nature 279:56-60
Bath, M. (1960) Crustal structure of Iceland, J. Geophys. Res. 65:1793-1807
Beblo, M., Bjornsson, A. (1978) Magnetotelluric investigation of the lower crust and upper mantle beneath Iceland. J. Geophys. 45:1-16
Beblo, M., Bjornsson, A. (1980) A model of electrical resistivity beneath NE-Iceland; Correlation with temperature. J. Geophys. 47:184-190
Beloussov, V.V., Milanovskiy, Y.Y. (1976) On the tectonic and tectonic position of Iceland. Soc. Sci. Islandica, Greinar 5:96-120
Bemmelen, van R.W. (1972) Geodynamic models; an evaluation and a synthesis. Amsterdam, Elsevier
Birch, F. (1969) Density and composition of the upper mantle: first approximation as an olivine layer. In: The Earth's crust and upper mantle, P.J., Hart, (Ed.): pp. 18-36. Washington: Am. Geophys Union
Bott, M.H.P. (1965) The upper mantle beneath Iceland. Geophys. J. 9:275-277
Bott, M.H.P. (1974) Deep structure, evolution and origin of the Icelandic transverse ridge. In: Geodynamics of Iceland and the North Atlantic Area, L. Kristiansson (Ed.): pp. 33-47. Dordrecht, Reidel
Bott, M.H.P., Gunnarsson, K. (1980) Crustal structure of the IcelandFaeroe Ridge. J. Geophys. 47:221-227
Bullard, E. C., Everett, J.E., Smith, A. G. (1965) The fit of the continents around the Atlantic. Philos. Trans. R. Soc. London, Ser. A: 258:41-51
Christensen, N.I. (1978) Ophiolites, seismic velocities and oceanic crustal structure. Tectonophysics 47:131-157
Christensen, N.I., Salisbury, M.H. (1976) Structure and constitution of the lower oceanic crust. Rev. Geophys. Space Phys. 13:57-86
Einarsson, P. (1979) Travel times recorded at Icelandic seismograph stations during the Reykjanes Ridge Iceland Seismic Project (RRISP). Pub!. Sci. Inst. Univ. Iceland RH-79-10
Einarsson, T. (1954) A survey of gravity in Iceland. Soc. Sci. Islandica 30
Fl6venz, O.G. (1980) Seismic structure of the Icelandic crust above layer three and the relation between body wave velocity and the alteration of the basaltic crust. J. Geophys. 47:211-220
Francis, T.J.G. (1969) Upper mantle structure along the axis of the Mid-Atlantic Ridge near Iceland. Geophys. J.R. Astron. Soc. 17:507-520
Gebrande, H. (1976) A seismic-ray tracing method for two-dimensional inhomogenous media. In: Explosion seimology in central Europe, P. Giese, C. Prodehl, A. Stein (Eds.): 162-167. Berlin, Heidelberg, New York; Springer
Goldflam, P., Weigel, W., Loncarevic, B. (1980) Seismic structure along RRISP - Profile I on the south-east flank of the Reykjanes Ridge. J. Geophys. 47:250-260
Green, D. H., Ringwood, A. E. (1963) Mineral assemblages in a model mantle composition. J. Geophys. Res. 68:937-945
Hashin, Z. (1966) Elasticity of ceramic systems. In: Ceramic microstructures, R.M. Fulrath, J.A. Pask (Eds.): pp. 313-341. New York, London, Sydney, Wiley
Hermance, J.F., Grillot, L.R. (1974) Constraints on temperatures beneath Iceland from magnetotelluric data. Phys. Earth. Planet. Inter. 8:1-12
Kroenke, L.W., Manghnani, M.H., Rai, C.S., Fryer, P., Ramananan-toandro, R. (1976) Elastic properties of selected ophiolitic rocks from Papua New Guinea: nature and composition of the oceanic lower crust and upper mantle. In: The Geophysics of the Pacific Ocean Basin and its Margin, G.H. Sutton, M.H. Manghnani, R. Moberly (Eds.): pp. 407-421. Washington: Am. Geophys. Union
Laughton, A.S. (1971) South Labrador Sea and the evolution of the North Atlantic. Nature 232:612-617
Long, R.E., Mitchell, M.G. (1970) Teleseismic P-wave delay time in Iceland. Geophys. J.R. Astron. Soc. 20:41-48
Palmason, G. (1971) Crustal structure of Iceland from explosion seismology. Reykjavik: Soc. Sci. Islandica 40
Palmason, G., Saemundsson, K. (1974) Iceland in relation to the MidAtlantic Ridge. Annu. Rev. Earth Planet. Sci. 2:25-50
Peterson, J.J., Fox, P.J., Schreiber, E. (1974) Newfoundland ophiolites and the geology of the oceanic layer. Nature 247:194-196
Rober, K.R., Thyssen, F. (1978) Messung der Schallgeschwindigkeit beim Ubergang fest - fliissig. DFG Kolloquium, Geowissenschaftliche Hochdruckforschung, Bad Honnef pp. 13-14
RRISP Working Group (1980) Reykjanes Ridge Iceland seismic experiment. J. Geophys. 47:228-238
Stefansson, R. (1966) Methods of focal mechanism studies with application on two Atlantic earthquakes. Tectonophysics 3:210-243
Tryggvason, E. (1962) Crustal structure of the Iceland region from dispersion of surface waves. Bull. Seismol. Soc. Am. 52:359-388
Tryggvason, E. (1964) Arrival times of P-waves and upper mantle structure. Bull. Seismol. Soc. Am. 54:727-736
Walsh, J.B. (1968) Attenuation in partially melted material. J. Geophys. Res. 73:2209-2216
Walsh, J.B. (1969) New analysis of attenuation in partially melted rock. J. Geophys. Res. 74:4333-4337
Wielandt, E. (1972) Anregung seismischer Wellen durch Unterwasserexplosionen. Diss., Univ. Karlsruhe, 90 pp.
Zverev, S.M., Kosminskaya, I.P., Krasilschikova, G.A., Mikhota, G. G. (1976) The crustal structure of Iceland and of the Iceland-Faeroe-Shetland region. Soc. Sci. Islandica, Greinar 5:72-95