Detection Of Underground Voids With Surface Waves

The conventional approach to the detection of underground voids by the Spectral Analysis of Surface Waves (SASW) method is through analysis of the phase difference between two transducers. This approach requires lengthy field testing and complex data manipulation, including filtering and unwrapping of the phase function. In the frequency domain two properties are measured for each frequency, its amplitude and wrapped phase value. This study proposes a method for the detection of underground voids by analyzing the measured power spectral density, a function related to the amplitude of the frequency. The proposed method does not require complex data manipulation since the power spectral density is directly measured and testing can be completed with an oscilliscope, decreasing the time required to conduct a seismic survey.