oa Factors in Determing the Survey Depth from Passive Surface Waves

Factors in Determing the Survey Depth from Passive Surface Waves Don Zhao, Geogiga Technology Corp., Alberta, Canada Abstract the passive surface wave technique has gained considerable attention for retrieving the subsurface shear velocity structure. Same as that in the active surface wave technique, the survey depth in the passive technique is affected by many factors. to study these factors and provide a guideline in designing the passive surface wave survey, we simulate a set of passive surface wave data and conduct several field tests with differenct lengths of arrays and different frequencies of geophones. the data are analyzed with the frequency-wavenumber (FK) method and the spatial auto-correlation (SPAC) method. the study shows that the larger length of array, the deeper the survey depth; the lower frequency of geophones, the deeper the survey depth. the result also demonstrates that the SPAC method is much better than the FK method in analyzing the passive surface waves, especially in the lower frequency range.