Enhanced converted-surface-wave imaging (CSWI) method for the detection of an elongated empty space using challenging seismic data collected at a desert site

The main purpose of this research was to investigate if it is possible do observe a seismic converted surface wave (CSW) response from an elongated void and detect its locaton. Positive results could complement and help resolve various unsertanties and possibilities from using other seismic surface-wave techniques, such as the backscatter analysis of surface waves (BASW) and the multi-channel analysis of surface waves (MASW) methods. We applied the converted-surface-wave imaging (CSWI) technique to seismic data obtained in arid environment. Straightforward application of the CSWI method did not provide any positive results. However, after looking further into involving alternative analysis steps and trasforms (e.g., filtering, FK filtering, amplitude envelope, etc.) is was possible to find a sequence, which was able to provide observations of the converted wave with its unique signature consistent with the elongated void location. As a result it was possible to uniquely resolve multiple candidate locations suggested by the BASW method. It was concluded that an algorithmically branching CSWI method can be a valuable tool to the the near-surface geophysical community.