Eastern Caldera

The Eastern Caldera Medium-Power Junction Box (MJ03E) supports geophysical instruments in the Eastern side of the 3-km-across caldera at the summit of Axial Seamount, at a water depth of ~1,520 meters. The instruments are designed to measure local seismic events associated with migration of melt and volatiles within the volcano, as well as far-field seismic events. They 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. A 635 meter-long electro-optical cable from Primary Node PN03B provides the junction box with significant power (375 V) and bandwidth (1 Gbs) to operate the instruments and transmit data to shore.