title: Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption.
abstract: Seismic observations in volcanically active calderas are challenging. A new cabled observatory atop Axial Seamount on the Juan de Fuca ridge allows unprecedented real-time monitoring of a submarine caldera. Beginning on 24 April 2015, the seismic network captured an eruption that culminated in explosive acoustic signals where lava erupted on the seafloor. Extensive seismic activity preceding the eruption shows that inflation is accommodated by the reactivation of an outward-dipping caldera ring fault, with strong tidal triggering indicating a critically stressed system. The ring fault accommodated deflation during the eruption and provided a pathway for a dike that propagated south and north beneath the caldera's east wall. Once north of the caldera, the eruption stepped westward, and a dike propagated along the extensional north rift.
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA 98195, USA. wilcock@uw.edu.
authors.forename: William S D
authors.initials: WS
authors.lastname: Wilcock
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
authors.forename: Maya
authors.initials: M
authors.lastname: Tolstoy
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
authors.forename: Felix
authors.initials: F
authors.lastname: Waldhauser
authors.affiliation: School of Oceanography, University of Washington, Seattle, WA 98195, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Garcia
authors.affiliation: Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA.
authors.forename: Yen Joe
authors.initials: YJ
authors.lastname: Tan
authors.affiliation: Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: DelWayne R
authors.initials: DR
authors.lastname: Bohnenstiehl
authors.affiliation: Geology Department, Western Washington University, Bellingham, WA 98225, USA.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Caplan-Auerbach
authors.affiliation: National Oceanic and Atmospheric Administration (NOAA), Pacific Marine Environmental Laboratory, Newport, OR 97365, USA.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Dziak
authors.affiliation: Institute for Geophysics, Jackson School of Geosciences, University of Texas, Austin, TX 78758, USA.
authors.forename: Adrien F
authors.initials: AF
authors.lastname: Arnulf
authors.affiliation: Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695, USA.
authors.forename: M Everett
authors.initials: ME
authors.lastname: Mann