Ground analyzing system and recording medium recording analysis program used therefor

A ground analyzing system for carrying out ground analysis by detecting surface waves generated by vibrating the surface of the ground in the vertical direction, said system comprising:

• first and second acceleration detectors disposed at a distance L from each other on the ground;
• a measuring instrument including a seismometer unit for receiving detection signals from the first and second acceleration detectors to generate first and second acceleration time-series signals;
• and
• a signal processing unit for receiving the first and second acceleration time-series signals to perform a signal processing based on a predetermined analysis program,
• wherein the signal processing unit performs Fourier transform to calculate power spectra and a cross spectrum, calculates a transfer function H(f) using the calculated power spectra and cross spectrum, calculates a phase difference Δθ(f) between the first and second acceleration time-series signals and a time difference Δt(f) therebetween using the calculated transfer function H(f), and further, calculates a mean propagation velocity Vr(f) of the surface waves and a depth D(f) on the basis of the calculated time difference Δt(f) and the distance L.