Gouge coring: Not as violent as it sounds! Scientists use gouge cores to investigate sediment stratigraphy in marshes and other terrestrial areas. The Eel River in Northern California is located near the Mendocino triple junction, where three seismic faults meet: the Cascadia Subduction Zone, the Mendocino Fracture Zone, and the San Andreas Fault. Sediments preserved in coastal settings such as the lower Eel River valley may record evidence of past seismic activity like subsidence or tsunamis. U