Morphology of Fault Scarps Associated With Subduction Initiation at the Puysegur Trench

The South Island Subduction Initiation Experiment (SISIE) surveyed the Puysegur region in February-March, 2018 on board the R/V Marcus Langseth. SISIE acquired Kongsberg EM122 multibeam bathymetry and backscatter data along the survey lines, to complement the multichannel seismic data, OBS data, gravity, magnetics, and subbottom penetration data obtained by the other shipboard systems. We combine the multibeam data with relevant segments of publicly available existing swath mapping data from other cruises in the area nearby (NBP1403, NBP9702, NBP0406, EW9513, RR1002) to perform an automated analysis of trends of linear bathymetric features, at grid resolution of 200, 300, and 400 m, using a mathematical technique to remove slopes of symmetric bathymetric features such as seamounts. The subset of linear scarps that corresponds to faults visible in the MCS and subbottom penetration data allows us to classify subgroups of young or active faults.