Fig. 16

Comparisons of estimated phase velocities obtained through DSPAC method with those obtained through conventional methods in case of noise-free synthetic data. The array shape is a slightly flattened triangle (R3-R6-R7). The legend is the same as that in Fig. 15 and “approx.” denotes the averaged distances among the receivers used to take the azimuthal average. The approximated SPAC method includes bias from the target and the DSPAC method works well