References

Adams, R.D., Early reflections of P'P' as an indication of upper mantle structure, Bull. Seis. Soc. Am., 58, 1933-1947, 1968

Akaogi, M. and S. Akimoto, Pyroxene-garnet solid equilibria in the systems Mg$_4$Si$_4$O$_{12}$-Mg$_3$Al$_2$Si$_3$O$_{12}$ and Fe$_4$Si$_4$O$_12$-Fe$_3$Al$_2$Si$_3$O$_{12}$ at high pressures and temperature, Phys. Earth Planet. Int., 15, 90-106, 1977

Akaogi, M., A. Navrotsky, T. Yagi and S. Akimoto, Pyroxene-garnet transformation: thermochemistry and elasticity of garnet solid solutions, and application to a pyrolitic mantle, in High-pressure research in mineral physics, edited by M. H. Manghnani and Y. Syono, pp. 251-260, Am. Geophys. Union, Washington D.C, 1987

Aki, K. and P.G. Richards, Quantitative seismology, theory and methods, vol. II, W.H. Freeman and Company, San Francisco, 1980

Anderson, D.L., Phase changes in the upper mantle, Science, 157, 1165-1173, 1967

Anderson, D.L., Petrology of the mantle, Mineral. Soc. Am. Spec. Pap., 3, 85-93, 1970

Anderson, D.L., Theory of the Earth, Blackwell Scientific Publications, Boston, Mass., 1989

Anderson, O.L., E. Schreiber, R.C. Liebermann and N. Soga, Some elastic constant data on minerals relevant to geophysics, Rev. Geophys., 6, 491-524, 1968

Baumgardt, D.H., Evidence for a P-wave velocity anomaly in D'', Geophys. Res. Lett., 16, 657-660, 1989

Benz, H.M. and J.E. Vidale, Sharpness of upper mantle discontinuities determined from high-frequency reflections, Nature, 365, 147-150, 1993

Bina, C.R., Mantle discontinuities, Rev. Geophys. Suppl., 783-793, 1991

Bina, C.R. and G. Helffrich, Phase transition Clapeyron slopes and transition zone seismic discontinuity topography, J. Geophys. Res., 99, 15853-1586, 1994

Bina, C.R. and B.I. Wood, The eclogite to garnet transition - experimental and thermodynamical constraints, Geophys. Res. Lett., 11, 955-958, 1984

Bina, C.R. and B.I. Wood,Olivine-spinel transitions: experimental and thermodynamic constraints and implications for the nature of the 410-km discontinuity, J. Geophys. Res., 92, 4853-4866, 1987

Birch, F. Elasticity and constitution of the Earth's interior, J. Geophys. Res., 57, 227-286, 1952

Bock, G., Sp phases from the Australian upper mantle, Geophys. J., 94, 73-81, 1988

Bock, G., Long-period S to P converted waves and the onset of partial melting beneath Oahu, Hawaii, Geophys. Res. Lett., 18, 869-872, 1991

Bock, G., Synthetic seismogram images of upper mantle structure: No evidence for a 520-km discontinuity, J. Geophys. Res., 99, 15843-15851, 1994

Bolt, B.A., M. O'Neill and A. Qamar, Seismic waves near 100$^{\circ}$: Is structure in core or upper mantle responsible?, Geophys. J. R. astr. Soc., 16, 475-487, 1968

Bolt, B.A., PdP and PKiKP waves and diffracted PcP waves, Geophys. J. R. astr. Soc., 20, 367-382, 1970

Bostock, M.G., Mantle stratigraphy and evolution of the Slave province, J. Geophys. Res., 103, 21183-21200, 1998

Bowman, J.R. and B.L.N. Kennett, An investigation of the upper mantle beneath NW Australia using a hybrid seismograph array, Geophys. J. Int., 101, 411-424, 1990

Bullen, K. E., The problem of the Earth's density variation, Bull. Seis. Soc. Am., 30, 235-250, 1940

Byerly, P. The Montana earthquake of June, 18, 1925, Bull. Seis. Soc. Am., 16, 209-265, 1926

Capon, J., Signal processing and frequency-wavenumber spectrum analysis for a large aperture seismic array, in: Methods in computational physics, Academic Press, 2-59, 1973

Castle, J.C. and K.C. Creager, NW Pacific slab rheology, the seismic cutoff, and the olivine to spinel phase change, Earth Planets Space, 50, 977-985, 1998

Castle, J.C. and K.C. Creager, A steeply dipping discontinuity in the lower mantle beneath Izu-Bonin, J. Geophys. Res., 104, 7279-7292, 1999

Chaljub, E. and A. Tarantola, Sensitivity of SS precursors to topography on the upper-mantle 660-km discontinuity, Geophys. Res. Lett., 24, 2613-2616, 1997

Christensen, U.R., Effects of phase transitions on mantle convection, Annu. Rev. Earth Planet. Sci., 23, 65-87, 1995

Corbishley, D.J., Structure under seismic arrays, Geophys. J. R. astr. Soc., 21, 415-425, 1970

Corrieu-Sipahalamani, V., Modèles dynamiques du manteau terrestre: observations et contraintes, PhD thesis, Université de Cergny-Pontoise, 1995

Creager, K.C. and T.H. Jordan, Slab penetration into the lower mantle beneath the Mariana and other island arcs of the northwest Pacific, J. Geophys. Res., 91, 3573-3589, 1986

Cummins, P.R., B.L.N. Kennett, J.R. Bowman and M.G. Bostock, The 520 km discontinuity?, Bull. Seis. Soc. Am., 82, 323-336, 1992

Davies, D., E.J. Kelly and J.R. Filson, Vespa process for analysis of seismic signals, Nature Phys. Sci., 232, 8-13, 1971

Davis, J.P. and M. Weber, Lower mantle velocity inhomogeneity observed at GRF array, Geophys. Res. Lett., 17, 187-190, 1990

Davis, J.P., R. Kind and I.S. Sacks, Precursors to P'P' re-examined using broad-band data, Geophys. J. Int., 99, 595-604, 1989

Deal, M.M. and G. Nolet, Slab temperature and thickness from seismic tomography, 2. Izu-Bonin, Japan, and Kuril subduction zones, J. Geophys. Res., 104, 28803-28812, 1999

Duecker, K.G. and A.F. Sheehan, Mantle discontinuity structure from midpoint stacks of converted P to S waves across the Yellowstone hotspot track, J. Geophys. Res., 102, 831308327, 1997

Dziewonski, A.M. and D.L. Anderson, Preliminary reference earth model, Phys. Earth Planet. Int., 25, 1970356, 1981

Egorkin, A.V. and N.I. Pavlenkova, Studies of mantle structure of U.S.S.R. territory on long range seismic profiles, Phys. Earth Planet. Int., 25, 12-26, 1981

Engdahl, E.R. and E.A. Flinn, Seismic waves reflected from discontinuities within the Earth's upper mantle, Science, 163, 177-179, 1968

Engdahl, E. R. and R.D. van der Hilst and R. P. Buland, Global teleseismic earthquake relocation with improved travel times and procedures for depth determination, Bull. Seis. Soc. Am., 88, 772-743, 1998

Estabrook, C.H. and R. Kind, The nature of the 660-kilometer upper mantle seismic discontinuity from precursors to the PP phase, Science, 274, 1179-1182, 1996

Faber, S. and G. Müller, Sp phases from the transition zone between the upper and lower mantle, Bull. Seis. Soc. Am., 70, 487-508, 1980

Flanagan, M.P. and P.M. Shearer, Global mapping of topography on transition zone velocity discontinuities by stacking SS precursors, J. Geophys. Res., 103, 2673-2692, 1998

Flanagan, M.P. and P.M. Shearer, A map of topography on the 410-km discontinuity from PP precursors, Geophys. Res. Lett., 26, 549-552, 1999

Forsyth, D.W., The evolution of the upper mantle beneath mid ocean ridges, Tectonophysics, 38, 89-118, 1977

Fuchs, K., Recently formed elastic anisotropy and petrological models for the continental subcrustal lithosphere in southern Germany, Phys. Earth Planet. Int., 31, 93-118, 1983

Gaherty J.B. and T.H. Jordan, Lehmann discontinuity as the base of an anisotropic layer beneath continents, Science, 268, 1468-1471, 1995

Gaherty, J.B., T.H. Jordan and L.S. Gee, Seismic structure of the upper mantle in a central Pacific corridor, J. Geophys. Res., 101, 22291-22309, 1996

Gaherty, J.B., M. Kato and T.H. Jordan, Seismological structure of the upper mantle: a regional comparison of seismic layering, Phys. Earth Planet. Int., 110, 21-41, 1999

Gasparik, T., The role of volatiles in the transition zone, J. Geophys. Res., 98, 4287-4299, 1993

Goncz, J.H. and J.R. Cleary, Variations in the structure of the upper mantle beneath Australia from Rayleigh wave observations, Geophys. J. R. astr. Soc., 44, 507-516, 1976

Goßler J. and R. Kind, Seismic evidence for very deep roots of continents, Earth Planet. Sci. Lett., 138, 1-13, 1996

Graves, R.W. and D.V. Helmberger, Upper mantle cross section from Tonga to Newfoundland, J. Geophys. Res., 93, 4701-4711, 1988

Green, D.H. and A.L. Hales, The traveltime of P waves to 30$^{\circ}$ in the central United States and upper mantle structure, Bull. Seis. Soc. Am., 58, 267-289, 1968

Green, D.H. and R.C. Liebermann, Phase equilibria and elastic properties of a pyrolite model for the oceanic upper mantle, Tectonophysics, 32, 61-92, 1976

Green, D.H. and A.E. Ringwood, The stability fields of aluminous pyroxene peridotite and garnet peridotite and their relevance in upper mantle structure, Earth Planet. Sci. Lett., 3, 151-160, 1967

Gu, Y, A.M. Dziewonski and C.B. Agee, Global de-correlation of the topography of transition zone discontinuities, Earth Planet. Sci. Lett., 157, 57-67, 1998

Gudmundsson, O. and M. Sambridge, A regionalised upper mantle (RUM) seismic model, J. Geophys. Res., 103, 7121-7136, 1998

Gutenberg, B., Untersuchungen zur Frage, bis zu welcher Tiefe die Erde kristallin ist, Zeitschr. f. Geophysik, 2, 24-29, 1926

Gutenberg, B., On the layer of relatively low wave velocity at a depth of about 80 kilometres, Bull. Seis. Soc. Am., 38, 121-148, 1948

Gutenberg, B., Waves reflected at the 'surface' of the Earth: P'P'P'P', Bull. Seis. Soc. Am., 50, 71-79, 1960

Gutenberg, B. and C.F. Richter, On P'P' and related waves, Gerl. Beitr. Geophys., 41, 149-161, 1934

Haddon, R.A.W., E.S. Husebye and D.W. King, Origins of precursors to P'P', Phys. Earth Planet. Int., 14, 41-70, 1977

Hales, A.L., A seismic discontinuity in the lithosphere, Earth Planet. Sci. Lett., 7, 44-46, 1969

Hales, A.L., The travel times of P seismic phases and their relevance to the upper mantle velocity distribution, Tectonophysics, 13, 447-482, 1972

Hales, A.L., K.J. Muirhead and J.M. Rynn, A compressional velocity distribution for the upper mantle, Tectonophysics, 63, 309-348, 1980

Harjes, H.-P. and M. Henger, Array-Seismologie, Zeitschr. f. Geophysik, 39, 865-905, 1973

Helffrich, G. and C.R. Bina, Frequency dependence of the visibility and depths of mantle seismic discontinuities, Geophys. Res. Lett., 21, 2613-2616, 1994

Helffrich, G. and B.J. Wood, 410-km discontinuity sharpness and the form of the olivine $\alpha - \beta$ phase diagram: resolution of apparent seismic contradictions, Geophys. J. Int., 126, F1-F12, 1996

Herrin, E. and J. Taggert, Regional variation in P$_n$ velocity and their effect on the location of epicentres, Bull. Seis. Soc. Am., 52, 1037-1046, 1962

Herrmann, F., C. Stark and S. Chevrot, Characterising the sharpness of discontinuities by fixed scale singularity analysis of converted phases, suppl. EOS, AGU Fall Meeting, 2000

Hirn, A. C. Prodehl and L. Steinmetz, An experimental test of models of the lower lithosphere in Bretagne (France), Ann. Geophys., 31, 517-530, 1975

Hwang, L.J. and R.W. Clayton, A station catalogue of ISC arrivals: seismic station histories and station residuals, Open-File Report 91-295, Department of the Interior, U.S. Geological Survey, 1991

Ita, J. and L. Stixrude, Petrology, elasticity, and composition of the mantle transition zone, J. Geophys. Res., 97, 6849-6866, 1992

Ito, E. and E. Takahashi, Postspinel transformations in the system Mg$_2$SiO$_4$-Fe$_2$SiO$_4$ and some geophysical implications, J. Geophys. Res., 94, 10637-10646, 1989

Jahnke, G., Analyse schwacher teleseismischer Einsätze an kleinen Arrays: Möglichkeiten und Grenzen, Diplomarbeit, Georg-August Universität Göttingen, 1998

Jarrard, R.D., Relations among subduction parameters, Rev. Geophys., 24, 217-284, 1986

Jeanloz R. and A.B. Thompson, Phase transitions and mantle discontinuities, Revs. Geophys., 1, 51-74, 1983

Jeffreys, H., The structure of the Earth down to the 20$^{\circ}$ discontinuity, Mon. Not. R. Astr. Soc. Geophys. Suppl., 3, 401-422, 1936

Jenkins, D.M. and R.C. Newton, Experimental determination of the spinel peridotite to garnet peridotite inversion at 900$^{\circ}$C and 1000$^{\circ}$C in the system CaO-MgO-Al$_2$O$_3$-SiO$_2$ and at 900$^{\circ}$C with natural garnet and olivine, Contr. min. Petr., 68, 407-419, 1979

Ji, Y. and H.-C. Nataf, Detection of mantle plumes in the lower mantle by diffraction tomography: Hawaii, Earth Planet. Sci. Lett., 159, 99-115, 1998

Jones, L.E., J. Mori and D.V. Helmberger, Short-period constraints on the proposed transition zone discontinuity, J. Geophys. Res., 97, 8765-8774, 1992

Kanamori, H. and F. Press, How thick is the lithosphere, Nature, 226, 330, 1970

Karason, H. and R.D. van der Hilst, Improving global tomography models of P-wavespeed I: Incorporation of differential times for refracted and diffracted core phases (PKP, Pdiff), submitted to J. Geophys. Res., 2000

Karato, S.-I., On the Lehmann discontinuity, Geophys. Res. Lett., 19, 2255-2258, 1992

Karato, S.-I. and P. Wu, Rheology of the upper mantle: A synthesis, Science, 260, 771-778, 1993

Karato, S.-I., Phase transformations and rheological properties of mantle materials, in: Earth's deep interior, ed: D.J. Crossley, 223-272, 1997

Katsura, T. and E. Ito, The System Mg$_2$SiO$_4$-Fe$_2$SiO$_4$ at high pressures and temperatures: precise determination of stabilities of olivine, modified spinel and spinel, J. Geophys. Res., 94, 15663-15670, 1989

Kay, I., J.-M. Kendall, C. Thomson, D. White, I. Asudeh, B. Roberts and D. Francis, Shear wave splitting observation in the Archean craton of western Superior, Geophys. Res. Lett., 26, 2669-2672, 1999

Kelly, E.J., Response of seismic signals to wide-band signals, Linc. Lab. Techn. Note, 1967-30, 1967

Kennett, B.L.N. and E.R. Engdahl, Traveltimes for global earthquake location and phase identification, Geophys. J. Int., 105, 429-465, 1991

Kennett, B.L.N., E.R. Engdahl and R. Buland, Constraints on seismic velocities in the Earth from traveltimes, Geophys. J. Int., 122, 108-124, 1995

Kind, R., G.L. Kosarev, N.V. Petersen, Receiver functions at the stations of the German Regional Seismic Network (GRSN), Geophys. J. Int., 121, 191-202, 1995

King, D.W. R.A.W. Haddon and E.S. Husebye, Precursors to PP, Phys. Earth Planet. Int., 10, 103-127, 1975

Knopoff, L. The thickness of the lithosphere from the dispersion of surface waves, Geophys. J. R. astr. Soc., 74, 55-81, 1983

Langston, C. A., Structure under Mount Rainier, Washington, inferred from teleseismic body waves, J. Geophys. Res., 84, 4749-4762, 1979

Lees, A.C., M.S.T. Bukowinski and R. Jeanloz, Reflection properties of phase transition and compositional models of the 670-km discontinuity, J. Geophys. Res., 88, 8145-8159, 1983

LeFevre, L.V. and D.V. Helmberger, Upper mantle P velocity structure of the Canadian shield, J. Geophys. Res., 94, 17749-17465, 1989

Lehmann, I., P', Bur. Centre Seism. Internat., A14, 3-31, 1936

Lehmann, I., Velocities of longitudinal waves in the upper part of the Earth's mantle, Ann. Geophys., 15, 93-113, 1959

Lehmann, I., S and the structure of the upper mantle, Geophys. J. R. astr. Soc., 4, 124-138, 1961

Leven, J.H., I. Jackson and A.E. Ringwood, Upper mantle seismic anisotropy and lithospheric decoupling, Nature, 289, 234-239, 1981

Li, A., K. M. Fischer, M.E. Wysession and T.J. Clarke, Mantle discontinuities and temperature under the North American continental keel, Nature, 395, 160-163, 1998

Li, X., R. Kind, K. Priestley, S.V. Sobolev, F. Tilmann, X. Yuan and M. Weber, Mapping the Hawaiian plume conduit with converted seismic waves, submitted to Science, 2000

MacGregor, I.D., The effect of CaO, Cr$_2$O$_3$, Fe$_2$O$_3$ and Al$_2$O$_3$ on the stability of spinel and garnet peridotites, Phys. Earth Planet. Int., 3, 372-377, 1970

Manchee, E.B. and D.H. Weichert, Epicentral uncertainties and detection probabilities from the Yellowknife seismic array data, Bull. Seis. Soc. Am., 58, 1359-1377, 1968

Mechie, J., A.V. Fuchs, T. Ryberg, L. Solodilov and F. Wenzel, P-wave mantle velocity structure beneath northern Eurasia from long-range recordings along the profile Quartz, Phys. Earth Planet. Int., 79, 269-286, 1993

Melbourne, T. and D. Helmberger, Fine structure of the 410-km discontinuity, J. Geophys. Res., 103, 10091-10102, 1998

Mohorovicic, A. Das Beben vom 8.X.1909, Jb. met. Obs. Zagreb, 9, 1-63, 1909

Morgan, J., Convection plumes in the lower mantle, Nature, 230, 42-43, 1971

Müller, G., The reflectivity method: a tutorial, J. Geophys., 58, 153-174, 1985

Müller, D., W.R. Roest, J.-Y. Royer, L.M. Gabagan and J.-G. Sclater, Digital isochrones of the world's ocean floor, J. Geophys. Res., 102, 3211-3214, 1997

Muirhead, K.J. and R. Datt, The N-th root process applied to seismic array data, Geophys. J. R. astr. Soc., 47, 197-210, 1976

Nakanishi, I., Reflections of P'P' from upper mantle discontinuities beneath the Mid-Atlantic ridge, Geophys. Jour., 93, 335-346, 1988

Nakanishi, I., A search for topography of the mantle discontinuities from precursors to P'P', Jour. Phys. Earth, 37, 297-301, 1989

Neele, F., Sharp 400-km discontinuity from short-period P reflections, Geophys. Res. Lett., 23, 419-422, 1996

Neele, F., H. deRegt and J. VanDecar, Gross errors in upper-mantle discontinuity topography from underside reflection data, Geophys. J. Int., 129, 194-204, 1997

Neele, F. and R. Snieder, Topography of the 400 km discontinuity from observations of long-period P$^{400}$P phases, Geophys. J. Int., 109, 670-682, 1992

Nielsen, L., H. Thybo and L. Solodilov, Seismic tomographic inversion of Russian PNE data along profile Kraton, Geophys. Res. Lett., 26, 3413-3416, 1999

Nishimura, C. E. and D. W. Forsyth, The anisotropic structure of the upper mantle in the Pacific, Geophys. J. R. Astron. Soc., 96, 203-229, 1989

Nixon, P.H. (ed.), Mantle xenoliths, John Wiley, New York, 1987

Oldham, R.D., The constitution of the Earth, Quart. Jour. Geol. Sci., 63, 456-472, 1906

O'Neill H.St.C. and H. Palme, Composition of the silicate mantle: Implications for accretion and core formation, in: The Earth's mantle, ed.: I. Jackson, Cambridge University Press, Cambridge, UK

Owens, T.J., G. Zandt and S.R. Taylor, Seismic evidence for an ancient rift beneath the Cumberland Plateau, Tennessee: A detailed analysis of broadband teleseismic P waveforms, J. Geophys. Res., 89, 7783-7795, 1984

Oxburgh, E.R. and D.L. Turcotte, Mechanisms of continental drift, Rep. Progress Phys., 41, 1249-1312, 1978

Parsons, B. and J.G. Sclater, An analysis of the variation of ocean floor bathymetry and heat flow with age, J. Geophys. Res., 82, 803-827, 1977

Paulssen, H., Evidence for a sharp 670-km discontinuity as inferred from P-to-S converted phases, J. Geophys. Res., 93, 10489-10500, 1988

Petersen, N., J. Goßler, R. Kind, K. Stammler and L. Vinnik, Precursors to SS and the structure of the transition zone of the north-western Pacific, Geophys. Res. Lett., 20, 281-284, 1993

Posmentier, E.S. and R.W. Herrmann, Cophase: An ad hoc array processor, J. Geophys. Res., 76, 2194-2201, 1971

Priestley, K. F., J. Cipar, A. Egorkin and N. Pavlenkova, Upper-mantle velocity structure beneath the Siberian platform, Geophys. J. Int., 118, 369-378, 1994

Revenaugh, J.S., The nature of mantle layering from first order reverberations, PhD thesis, Mass. Inst. Tech., Cambridge, Mass., 1989

Revenaugh, J. and T.H. Jordan, Observations of first order mantle reverberations, Bull. Seis. Soc. Am., 77, 1704-1717, 1987

Revenaugh, J. and T.H. Jordan, A study of mantle layering beneath the western Pacific, J. Geophys. Res., 94, 5787-5813, 1989

Revenaugh, J. and T.H. Jordan, Mantle layering from ScS reverberations 1. Waveform inversion of zeroth-order reverberations, J. Geophys. Res., 96, 19749-19762, 1991

Revenaugh, J. and T.H. Jordan, Mantle layering from ScS reverberations 2. The transition zone, J. Geophys. Res., 96, 19763-19780, 1991a

Revenaugh, J. and T.H. Jordan, Mantle layering from ScS reverberations 3. The upper mantle, J. Geophys. Res., 96, 19781-19810, 1991b

Revenaugh, J. and T.H. Jordan, Mantle layering from ScS reverberations, 4. The lower mantle and core-mantle boundary, J. Geophys. Res., 96, 19811-19824, 1991c

Ribe, N.M. and U.R. Christensen, Three-dimensional modelling of plume-lithosphere interaction, J. Geophys. Res., 99, 669-682, 1994

Richards, M.A. and C.W. Wicks jr., S-P conversion from the transition zone beneath Tonga and the nature of the 670 km discontinuity, Geophys. J. Int., 101, 1-35, 1990

Richards, P.G., Seismic waves reflected from velocity gradient anomalies within the Earth's upper mantle, Zeitschr. f. Geophys, 38, 517-527, 1972

Rigden, S.M., G.D. Gwanmesia, J.D. Fitzgerald, I. Jackson, and R.C. Liebermann, Spinel elasticity and seismic structure of the transition zone of the mantle, Nature, 354, 143-145, 1991

Rost, S. and M. Weber, A reflector at 200 km depth in the northwestern Pacific, in preparation, 2000

Sacks, I.S., J.A. Snoke and E.S. Husebye, Lithosphere thickness beneath the Baltic shield, Tectonophysics, 56, 101-110, 1979

Sawamoto, H. Orthorhombic perovskite (Mg,Fe)SiO$_3$ and constitution of the lower mantle, in: High pressure research, edited by M.H. Manghnani and S. Akimoto, Academic Press, New York, 219-244, 1977

Schubert, G., D.A. Yuen and D.L. Turcotte, Role of phase transitions in a dynamic mantle, Geophys. J. R. astr. Soc., 42, 705-735, 1975

Shearer, P.M., Seismic imaging of upper mantle structure with new evidence for a 520 km discontinuity, Nature, 344, 121-126, 1990

Shearer, P.M., Constraints on upper mantle discontinuities from observations of long-period reflected and converted phases, J. Geophys. Res., 96, 18147-18182, 1991

Shearer, P.M. and M.P. Flanagan, Seismic velocity and density jumps across the 410- and 660-kilometer discontinuities, Science, 285, 1545-1548, 1999

Simpson, D.W., R.F. Mereu and D.W. King, An array study of P wave velocities in the upper mantle transition zone beneath northeastern Australia, Bull. Seis. Soc. Am., 64, 1757-1788, 1974

Stammler, K., Ein Beitrag zur Untersuchung des oberen Erdmantels mit Hilfe von PS-Konversionsphasen, PhD dissertation, Friedrich-Alexander-Universität, Erlangen-Nürnberg, 1992

Stammler, K., R. Kind, G.L. Kosarev, A. Plesinger, J. Horalek, L. Qiyuan and L.P. Vinnik, Broadband observations of PS conversions from the upper mantle in Eurasia, Geophys. J. Int., 105, 801-804, 1991

Steinberger, B. and R.J. O'Connell, Advection of plumes in mantle flow: implications for hotspot motion, mantle viscosity and plume distribution, Geophys. J. Int., 132, 412-434, 1998

Stixrude, L., R.J. Hemley, Y. Fei and H.K. Mao, Thermoelasticity of silicate perovskite and magnesiowüstite and stratification of the Earth's mantle, Science, 257, 1099-1101, 1992

Stöffler, D., Minerals in the deep Earth: message from the asteroid belt, Science, 278, 1576-1577, 1997

Thybo, H. and E. Perchuc, The seismic 8$^{\circ}$ discontinuity and partial melting in the continental mantle, Science, 275, 1626-1629, 1997

Tittgemeyer, M., F. Wenzel and K. Fuchs, On the nature of P$_n$, J. Geophys. Res., submitted, 1999

Vasco, D.W., L.R. Johnson and J. Pulliam, Lateral variations in mantle velocity structure and discontinuities determined from P, PP, S, SS, and SS-S$_d$S travel time residuals, J. Geophys. Res., 100, 24037-24059, 1995

Vidale, J.E. and H.M. Benz, Upper-mantle seismic discontinuities and the thermal structure of subduction zones, Nature, 356, 678-683, 1992

Vinnik, L.P., Detection of waves converted from P to SV in the mantle, Phys. Earth Planet. Int., 15, 39-45, 1977

Wajeman, N., Detection of underside P reflections of mantle discontinuities by stacking broadband data, Geophys. Res. Lett., 15, 669-672, 1988

Walck, M.C., The P-wave upper mantle structure beneath an active spreading centre: the Gulf of California, Geophys. J. R. astr. Soc., 76, 697-723, 1984

Webb, S.A. And B.J. Wood, Spinel-pyroxene-garnet relationships and their dependence on Cr/Al ratio, Contr. to Mineralogy and Petrology, 92, 471-480, 1986

Weber, M., Computations of body-wave seismograms in absorbing 2-D media using the Gaussian beam method: comparison with exact methods, Geophys. J. Int., 92, 9-24, 1988

Weber, M. Subduction zones, their influence on travel times and amplitudes of P-waves, Geophys. J. Int., 101, 529-544, 1990

Weichert, D.H. and K. Whitham, Calibration of the Yellowknife seismic array with first zone explosions, Geophys. J. R. astr. Soc., 18, 461-476, 1969

Weidner, D.J. and Y. Wang, Chemical- and Clapeyron-induced buoyancy at the 660 km discontinuity, J. Geophys. Res., 103, 7431-7441, 1998

Wessel, P. and L. Kroenke, A geometric technique for relocating hotspots and refining absolute plate motions, Nature, 387, 365-369, 1997

Widiyantoro, S. and R.D. van der Hilst, Mantle structure beneath Indonesia inferred from high resolution tomographic imaging, Geophys. J. Int., 130, 167-182, 1997

Willmore, P.L. Seismic experiments on the North German explosions 1946 to 1947, Phil. Transact. R. Soc., London, 242 (ser A no. 843), 123-151, 1949

Wilson, T., A possible origin of the Hawaiian islands, Can. Jour. Phys., 41, 863-870, 1963

Wolfe, C.J. and P.G. Silver, Seismic anisotropy of oceanic upper mantle: Shear wave splitting methodologies and observations, J. Geophys. Res., 103, 749-771, 1998

Wood, B.J. and D.A. Yuen, The role of lithospheric phase transitions on seafloor flattening at old ages, Earth Planet. Sci. Lett., 66, 303-314, 1983

Wood, B.J., The effect of H$_2$O on the 410-kilometer seismic discontinuity, Science, 268, 74-76, 1995

Woods, M.T., J.-J. Leveque, E.A. Okal and M. Cara, Two-station measurements of Rayleigh wave group velocity along the Hawaiian swell, Geophys. Res. Lett., 18, 105-108, 1991

Woodward, R.L. and G. Masters, Global upper mantle structure from long-period differential travel times, J. Geophys. Res., 96, 6351-6377, 1991

Wright, C., Array studies of seismic waves arriving between P and PP in the distance range 90$^{\circ}$ to 115$^{\circ}$, Bull. Seis. Soc. Am., 62, 385-400, 1972

Wright, C. and K.J. Muirhead, Longitudinal waves from the Novaya Zemlya nuclear explosion of October 27, 1966, recorded at the Warramunga seismic array, J. Geophys. Res., 74, 2034-2048, 1969

Xu, F., P.S. Earle and J.E. Vidale, Survey of precursors to P'P': constraints on mantle discontinuities, suppl. EOS, AGU fall Meeting, 1999

Young, C.J. and T. Lay, Evidence for a shear velocity discontinuity in the lower mantle beneath India and the Indian ocean, Phys. Earth Planet. Int., 49, 37-53, 1987

Young, C.J. and T. Lay, Multiple phase analysis of the shear velocity increase in the D'' region beneath Alaska, J. Geophys. Res., 95, 17385-17402, 1990