For intensity of volcanic and seismic activity and the excitement of geophysical exploration, few places on Earth can match the Kamchatka-Aleutian junction, where the torn Pacific slab dives into the asthenosphere, carrying with it the distal end of the Emperor-Hawaiian Seamount Chain. Thus, it was fitting that researchers with a focus on North Pacific subduction began, in Petropavlovsk-Kamchatsky, Russia, their second round of biennial meetings that have cycled through that city, Sapporo, Japan, and Fairbanks, Alaska. The 4th Biennial International Workshop on Japan Kamchatka Aleutian Subduction Processes )JKASP( convened at the Institute of Volcanology and Seismology )IVS( of the Russian Academy of Sciences, recently formed through unification of the Institute of Volcanology and Institute of Volcanic Geology and Geochemistry.