A generic formulation for microtremor exploration methods using three‐component records from a circular array

摘要: SUMMARY We present a generic formulation for analysis methods that estimate phase velocities of Rayleigh and Love waves, by way intermediary quantities called ‘spectral ratios’, using three-component records microtremors from circular array sensors. At each time instant, the set are expanded in Fourier series with respect to azimuth, so we obtain coefficients represented form complex histories. We then power- cross-spectral densities those coefficients. The spectral densities, thus obtained, generally contain information on velocities, powers arrival directions individual modes waves. By taking quotient two different sorts such can cancel out their directions, extract alone. ratios have be estimated, practice, basis finite number seismic sensors either evenly or unevenly spaced around circumference. describe general procedure estimation, discuss effects directional aliasing configuration estimates ratios. also biases caused presence incoherent noise. our method, it is possible central direction microtremors, ellipticity whether waves prograde retrograde.