Fig. 11
From: Estimation of phase velocity using array observation of microtremors with arbitrary shape
Comparisons of estimated phase velocities obtained through DSPAC method with those obtained through conventional methods (synthetic data). The array shape is an equilateral triangle (R4-R6-R7), except for “FK (6 RCVRs)”. “BIDO” denotes the results when the program code, BIDO 3.0, developed by Cho (2020b), is applied, and RCVR is the receiver. The FK method (6 RCVRs) provides reasonable results in the very narrow frequency range of 9 to 12 Hz. On the other hand, other methods work very well, and provide almost identical results; however, they are strongly affected by noise. To avoid spatial aliasing in the analysis of the FK method, we searched over a limited range of phase velocities, which resulted in the misalignment with the target value in the frequency range above 12 Hz