Low-frequency acoustic observations with cabled observatories on the Juan de Fuca Ridge

Abstract

In the Northeast Pacific Ocean, the NSF Ocean Observatories Initiative (OOI) and Ocean Networks Canada (ONC) operate regional cabled observatories that include a network of seismometers and hydrophones enclosing the northern half of the Juan de Fuca plate, and local observatories at two sites on the Juan de Fuca Ridge: Axial Seamount (OOI) and the Endeavour segment (ONC). At each ridge site, local networks of seismometers and hydrophones provide a tool to monitor in real time the seismic and acoustic signals associated with volcanic, tectonic, and hydrothermal processes. In 2015, Axial Seamount erupted a few months after the installation of the OOI. Following the eruption, regionally recorded T-phases were used to track a dike propagating along the Axial North Rift. Acoustic signals from impulsive sources associated with lava flows, detected eruptions in the caldera and on the North Rift. Diffuse acoustic signals were also associated with the later stages of the eruption. The low-frequency acoustic capabilities of the OOI and ONC cabled observatories are underutilized and future applications could include the reestablishment of regional acoustic earthquake monitoring, tracking eruptions in real time to guide rapid autonomous and ship-based response efforts, and enhanced studies of fin and blue whales.In the Northeast Pacific Ocean, the NSF Ocean Observatories Initiative (OOI) and Ocean Networks Canada (ONC) operate regional cabled observatories that include a network of seismometers and hydrophones enclosing the northern half of the Juan de Fuca plate, and local observatories at two sites on the Juan de Fuca Ridge: Axial Seamount (OOI) and the Endeavour segment (ONC). At each ridge site, local networks of seismometers and hydrophones provide a tool to monitor in real time the seismic and acoustic signals associated with volcanic, tectonic, and hydrothermal processes. In 2015, Axial Seamount erupted a few months after the installation of the OOI. Following the eruption, regionally recorded T-phases were used to track a dike propagating along the Axial North Rift. Acoustic signals from impulsive sources associated with lava flows, detected eruptions in the caldera and on the North Rift. Diffuse acoustic signals were also associated with the later stages of the eruption. The low-frequency acoustic capabi...