Axial Seamount on the Juan de Fuca spreading center is an optimal site for a long-term observatory. It is located just one day by ship from the Washington and Oregon coasts and it is one of the main experimental sites on the RSN. It is the most magmatically robust volcano on the spreading center, having erupted in 1998 and most recently in April 2011. It hosts numerous active hydrothermal fields and abundant sites of diffuse flow (Kelley et al., 2014). It is one of the best-studied volcanoes along the global mid-ocean ridge spreading center and the only site where in situ pressure sensors have documented up to 13 cm/year summit inflation prior to an eruption (Nooner and Chadwick, 2009).
On August 8, 2014, all secondary infrastructure (cables, junction boxes and instruments) were connected to Primary Node PN3B. the node provides power and communication to five Medium Power J-Boxes that allow access to the Ashes and International District hydrothermal vent fields and to the Central and Eastern Caldera Site. Real-time high definition video will provide unprecedented views of macrofaunal and microbial communities at the vents and chemical sensors and thermistor arrays will provide information on the environmental conditions in which the biological communities thrive. The instrumentation will also yield information on the impact of flow perturbations associated with eruptive and seismic events on biological communities. Other sensors now installed include an situ mass spectrometer for fluid – volatile chemistry, broadband and short-period seismometers to monitor earthquake and magma migration activity, temperature and chemical probes in diffuse and black smoker sites, fluid and DNA samplers, and pressure-tilt meters for measurement of preeruptive inflation events and post eruptive deflation. The in situ DNA sampler initially will focuses on in-situ filtering and preservation of time series samples in the El Gordo diffuse flow site. The instrument array at Axial, now fully installed, is the largest single in situ experiment in the global ocean focused on long-term measurements of underwater volcanoes with transmission of real-time data and imagery back to shore. Ocean Leadership will announce when data are flowing through the Cyberinfratructure portion of the Ocean Observatories Initiative in 2015.
Location: 46.1ºN 130.0ºW Water Depth: 1510-1530 meters