Summary
A velocity model for theP-wave is obtained for the entire mantle, by inversion ofdT/dΔ-data from travel times of 473 earthquakes and explosions registered at 13 seismological observatories in Sweden and Finland. As a check, the travel times resulting from this model are found to be in good agreement with our observed travel times. The observations are distributed over the entire azimuth range with respect to the recording stations. The effect of the core upon the observeddT/dΔ-values is significant from about 95° distance outwards. The estimate of the core radius from this model is 3480 km which corresponds to about 97° of epicentral distance. The resulting model has sudden changes inP-velocity gradient at about 65, 115, 400, 780, 970, 1100, 1350, 2320, 2600 and 2710 km depth, which correspond roughly to 10°, 14°, 19.5°, 29°, 40°, 46°, 54°, 80°, 86° and 90° epicentral distance, respectively.
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On leave from Geophysical Institute, Tehran University, Tehran, Iran
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Enayatollah, M.A. Continental-array measurements ofP-wave velocities in the mantle. PAGEOPH 94, 136–147 (1972). https://doi.org/10.1007/BF00875676
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DOI: https://doi.org/10.1007/BF00875676