Wilcock, W.S.D., R.P. Dziak, M. Tolstoy, W.W. Chadwick, Jr., S.L. Nooner, D.R. Bohnenstiehl, J. Caplan-Auerbach, F. Waldhauser, A.F. Arnulf, C. Baillard, T.-K. Lau, J.H. Haxel, Y.J. Tan, C. Garcia, S. Levy, and M.E. Mann (2018): The recent volcanic history of Axial Seamount: Geophysical insights into past eruption dynamics with an eye toward enhanced observations of future eruptions. Oceanography, 31 (1), 114–123, doi:10.5670/oceanog.2018.117.
Studies of underwater eruptions are essential to understand the processes that form oceanic crust, and the role submarine volcanoes have in exchanging heat and chemicals with the ocean and in supporting chemosynthetic biological communities. The Ocean Observatories Initiative (OOI) Cabled Array at Axial Seamount is the world’s most advanced underwater volcano observatory, building upon 30+ years of sustained geophysical monitoring at this site with autonomous and remote systems as part of PMEL’s New Millennium Observatory (NeMO). Only months after the Cabled Array’s installation, it recorded an eruption of Axial Seamount in April 2015, following two prior eruptions that occurred in 1998 and 2011.
Between eruptions, replenishment of the magma reservoir within the seamount occurs and is focused beneath the southeast part of the caldera located at the volcano’s summit. This influx of magma leads to steady inflation (uplift) of the caldera floor and increasing rates of earthquake activity. During eruptions, the volcano’s caldera floor deflates (subsides) by several meters over a time period of days to weeks, which also coincides with high levels of earthquake activity as magma is injected out into rift zones on the volcano’s flanks and lava erupts onto the seafloor. Cabled Array seismic data show that earthquakes occur along a “ring” fault that encircles the edges of the caldera. Moreover, eruptions appear to occur at a predictable level of inflation; hence, it should be possible to time deployments of additional cabled and autonomous instrumentation to further enhance observations of the next eruption.