Velocities of long period surface waves and microseisms and their use in structural studies. I. Mantle Love and mantle Rayleigh waves and the structure of the earth's upper mantle. II. Microseisms and their application to seismic exploration

TL;DRAbstract

Part I: Phase velocities of Love waves from five major earthquakes are measured over six great circle paths in the period range of 50 to 400 seconds. For two of the great circle paths the phase velocities of Rayleigh waves are also obtained. The digitized seismograph traces are Fourier analyzed, and the phase spectra are used in determining the phase velocities. Where the great circle paths are close, the phase velocities over these paths are found to be in very good agreement with each other indicating that the measured velocities are accurate and reliable. Phase velocities of Love waves over paths that 1ie far from each other are different, and this difference is consistent and much greater than the experimental error. From this it is concluded that there are lateral variations in the structure of the earth's mantle. The phase velocity data are compared with theoretical dispersion curves of seven different earth models. None of these models fit the data. Two new upper man

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