Axial Seamount (some of the manuscripts in this special section refer to the edifice with the more precise name of “Axial Volcano”), a large ridge axis volcano, is located on the central segment of the Juan de Fuca Ridge approximately 250 nautical miles west of the Washington/Oregon/British Columbia coast. Currently both volcanically and hydrothermally active, Axial lies directly at the intersection of the Cobb-Eickelberg Seamount Chain and the Juan de Fuca Ridge (Figure 1). The volcanic activity associated with the seamount formation strongly interacts with, and is affected by, the normal seafloor spreading processes at the intersection. Because of this unique geologic setting, its proximity to west coast ports and oceanographie institutions, and its shallow depth, Axial has become the focus of a large number of scientific investigations over the past decade.