The Axial Base Seafloor site is located near the base of the Axial Seamount at the far western edge of the Juan de Fuca tectonic plate, at ~2,600 meters water deep. The site contains a Medium-Power JBox (MJ03A) and a Low-Power JBox (LJ03A). Axial Seamount is the largest and most magmatically robust volcano on the Juan de Fuca Ridge. Axial Seamount is far from the continental shelf (>350 km) and represents an open-ocean or pelagic site in the continuum of observing scales represented in the OOI’s Cabled Array. Here, large-scale currents including the North Pacific Current, the subpolar gyre and the northern end of the California Current interact. These currents transport heat, salt, oxygen, and biota, all of which are crucial to the region’s ecosystem. However, their variability arises from forcing as varied as tides and winds to interannual (El Niño) to decadal (Pacific Decadal Oscillation) timescales.

As with other JBoxes, these rests on the seafloor, contain geophysical and near seafloor water column instrumentation, and are attached to a fiber-optic cable. The fiber-optic cable provides the JBoxes with a significant power and 1 Gb communication bandwidth that provides two-way communication to instruments for their operation and transmission of data to shore. This seafloor site is co-located with a Deep and Shallow Profiler Mooring, which collect complementary water column data.


This site includes following instruments. To learn more about an instrument type, select its name on the left. To see the relevant data streams for a particular instrument, select the instrument code in the first column which will take you to the OOI Data Portal.

Instrument Depth Node Instrument
Make & Model
RS03AXBS-LJ03A-12-CTDPFB301 2,522m Low-Power JBox (LJ03A) CTD (CTDPFB) Sea-Bird - SBE 16plusV2
RS03AXBS-LJ03A-12-DOSTAD301 2,522m Low-Power JBox (LJ03A) Dissolved Oxygen (DOSTAD) Aanderaa - Optode 4831
RS03AXBS-LJ03A-09-HYDBBA302 2,594m Low-Power JBox (LJ03A) Broadband Acoustic Receiver (Hydrophone) (HYDBBA) Ocean Sonics - icListen HF
RS03AXBS-LJ03A-11-OPTAAC303 2,594m Low-Power JBox (LJ03A) Spectrophotometer (OPTAAC) WET Labs - AC-S Deep
RS03AXBS-LJ03A-10-ADCPTE303 2,594m Low-Power JBox (LJ03A) Velocity Profiler (150kHz) (ADCPTE) Teledyne RDI - Workhorse Quartermaster Monitor 150kHz
RS03AXBS-LJ03A-05-HPIESA301 2,639m Low-Power JBox (LJ03A) Horizontal Electric Field, Pressure and Inverted Echo Sounder (HPIESA) Sanford, UW - cabled HPIES
RS03AXBS-MJ03A-12-VEL3DB301 2,642m Medium-Power JBox (MJ03A) 3-D Single Point Velocity Meter (VEL3DB) Nobska - MAVS-4
RS03AXBS-MJ03A-05-OBSBBA303 2,642m Medium-Power JBox (MJ03A) Broadband Ocean Bottom Seismometer (OBSBBA) Guralp - CMG-1T/5T
RS03AXBS-MJ03A-05-HYDLFA301 2,642m Medium-Power JBox (MJ03A) Low Frequency Acoustic Receiver (Hydrophone) (HYDLFA) HTI - 90-U
RS03AXBS-MJ03A-06-PRESTA301 2,642m Medium-Power JBox (MJ03A) Tidal Seafloor Pressure (PRESTA) Sea-Bird - SBE 54