Upper Mantle Shear Velocity Model

Phase velocities in period range between 40 an 150 s are generously donated by Harvard University and Utrecht University. These phase velocity data sets are described by Ekström et al. (1997) and Trampert and Woodhouse (1995).

The group velocity measurements at periods between 16 and 200s are performed at the Center for Imaging the Earth's Interior in the University of Colorado at Boulder. The group velocities are measured with the frequency-time analysis (Levshin et al., 1989) in which for every waveform a human analyst defines the frequency range of measurements and separate the signal form a variety of noise sources (e.g., overtones, fundamental modes of different types, other earthquakes, multipaths, scattered arrivals).