Microtremor mesurements are conducted at two sites using arrays of three-component sensors. The frequency-wavenumber spectrum analysis of measured motions leads to the following conclusions: (1) Horizontal motions reflect combined characteristics of Rayleigh- and Love-waves, while vertical motions those of Rayleigh waves; (2) Rayleigh- and Love-wave characteristics can be extracted from radial and transverse horizontal motions if they are propagated from the same azimuth; and(3)Both vertical and horizontal motions tend to be inversely dispersive when the response spectra of higher-modes are equivalent to or greater than that of the fundamental-mode.
