LAUSR

The Deep Sea Drilling Project (DSDP) or Ocean Drilling Program (ODP), and the recent International Discovery Program (IODP) usually acquire borehole geophysical data for planetary exploration. A recently developed shear wave imaging technique was applied to the acoustic waveform log data of the IODP U1473A hole to image a fault system about 40 m away from the borehole. The shear wave imaging not only allowed us to delineate the fault structure in the vicinity of the borehole, but also to determine the orientation of the fault system, providing much needed information for the interpretation of the tectonic situation of the well site. Theory and method for the imaging application are elaborated and data processing results are presented along with the supporting borehole geophysical data. Its successful application to the IODP U1473A hole suggests that the shear wave imaging technique can be applied to the previously recorded and future ODP/IOPD borehole acoustic data, promising the extraction of valuable geophysical and geological information.