You really get a feel for how big the Cascadia subduction zone is when you run along it for days....we did not give the ship waypoints north of latitude 36...they are just running towards Seattle, but this just happens to give perfect continuous coverage with the swath bathymetry of the lower slope, deep ocean, and the subduction zone in between. Lots of signs of fault-controlled topography on the slope. There is probably already swath (=multibeam) bathymetry coverage here but having more data allows the depth points to be regridded with more resolution. (multibeam/swath bathymetry focuses sound into narrow beams that are directed to numerous points to both sides of the ship. For the RV Melville, the area or swath covered is about 3 times the water depth...so is as much as 10 km wide here, but only 2 to 3 km when we were trying to follow that active fault between 34 1/2 and 36 deg north (because water was 600 m to 1200 m deep there)).

We finally have some motion on this ship..it is rolling a couple of degrees...but not a bad motion at all...if it was the former USGS ship the SP Lee the roll would be 10 to 20 deg for the same swell. Don will be barfing just reading about that.
Chris