The Shallow Porosity Structure of Shelf Sediments off Humboldt Bay, Northern California: A Towed Electromagnetic Survey.

We have completed a towed electromagnetic survey, mapping the electrical resistivity of the seafloor across an area of the Californian continental shelf off Humboldt Bay. Over 120 km of tow lines were completed, measuring resistivity profiles to 20 m depth continuously along track from water depths of 100 m to around 30 m. Our data show a high degree of variability in porosity structure along the shelf and we identify three distinct environments based on the resistivities recorded and the porosities inferred from them.