The International District Vent Field 2 Medium-Power Jbox, supports geophysical instruments near the International District Hydrothermal Field located on the eastern rift zone within the caldera of Axial Seamount. Instruments are attached to a Medium-Power J-Box and are mounted on/near the seafloor.

Instruments are designed to measure local seismic events associated with migration of melt and volatiles within the volcano, microseismic events associated with upwelling of boiling fluids beneath they hydrothermal field, as well as far-field seismic events. Instruments also measure uplift and deflation of the seafloor associated with ingress of melt within the underlying magma chamber, and collapse of the seafloor during diking-eruptive events. This site was chosen because Axial has erupted in 1988, 2011, and again in 2015. During the 2015 event, over 8,000 earthquakes were measured with the cabled geophysical array, and data were streamed live back to shore in real-time. Instruments within the nearby International District 2 site, monitors hydrothermal and biological activity within the vent field.

Seafloor instruments at the ASHES site are attached to a Medium-Power J-Box (MJ03C) through a series of extension cables. An ~ 2.2 km long extension cable from Primary Node PN3B provides the JBox with significant power (375 v) and bandwidth (1 Gbs) to operate the instruments and transmit data to shore.


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
RS03INT2-MJ03D-12-VEL3DB304 1,527m Medium-Power JBox (MJ03D) 3-D Single Point Velocity Meter (VEL3DB) Nobska - MAVS-4
RS03INT2-MJ03D-06-BOTPTA303 1,527m Medium-Power JBox (MJ03D) Bottom Pressure and Tilt (BOTPTA) PMEL/Chadwick - PMELcabled BPR/Tilt
RS03INT2-MJ03D-05-OBSSPA305 1,527m Medium-Power JBox (MJ03D) Short-Period Ocean Bottom Seismometer (OBSSPA) Guralp - CMG-6TF