Acoustic evidence for a broad, hydraulically active damage zone surrounding the Alpine Fault, New Zealand

We present an analysis of the wireline sonic logs acquired through Alpine Fault hanging wall rocks during the second phase of the Deep Fault Drilling Project (DFDP-2). Due to inaccuracy in the initial tool-processed slowness logs, a more robust reprocessing of the data using the slowness–time coherence method was required. The reprocessing of the data yielded slowness logs that provide a significantly better estimate of compressional and shear...