A decade of volcanic construction and destruction at the summit of NW Rota‐1 seamount: 2004–2014

Abstract

Arc volcanoes are important to our understanding of submarine volcanism because at some sites frequent eruptions cause them to grow and collapse on human timescales. This makes it possible to document volcanic processes. Active submarine eruptions have been observed at the summit of NW Rota‐1 in the Mariana Arc. We use remotely operated vehicle videography and repeat high‐resolution bathymetric surveys to construct geologic maps of the summit of NW Rota‐1 in 2009 and 2010 and relate them to the geologic evolution of the summit area over a 10 year period (2004–2014). We find that 2009 and 2010 were characterized by different eruptive styles, which affected the type and distribution of eruptive deposits at the summit. Year 2009 was characterized by ultraslow extrusion and autobrecciation of lava at a single eruptive vent, producing a large cone of blocky lava debris. In 2010, higher‐energy explosive eruptions occurred at multiple closely spaced vents, producing a thin blanket of pebble‐sized tephra overlying lava flow outcrops. A landslide that occurred between 2009 and 2010 had a major effect on lithofacies distribution by removing the debris cone and other unconsolidated deposits, revealing steep massive flow cliffs. This relatively rapid alternation between construction and destruction forms one end of a seamount growth and mass wasting spectrum. Intraplate seamounts, which tend to grow larger than arc volcanoes, experience collapse events that are orders of magnitude larger and much less frequent than those occurring at subduction zone settings. Our results highlight the interrelated cyclicity of eruptive activity and mass wasting at submarine arc volcanoes.

Hydroacoustic, Seismic, and Bathymetric Observations of the 2014 Submarine Eruption at Ahyi Seamount, Mariana Arc

“…At Monowai, which has a similar summit depth as Ahyi (<150 m), intermittent eruptive activity over many years has been interspersed with multiple landslides on different sectors of the volcano (Chadwick, Wright, et al, ; Watts et al, ; Wright et al, ). Similarly at NW Rota‐1, low‐level strombolian eruptive activity between 2003 and 2009 deposited volcaniclastic deposits on the upper southern slope of the volcano, which were then moved downslope in a major landslide in 2009 (Chadwick et al, ; Chadwick et al, ; Embley et al, ; Schnur et al, ). West Mata volcano was observed to be erupting continuously between 2008 and 2011 by direct ROV observations and remote hydrophone recordings (Dziak et al, ; Resing et al, ).…”

Hydrothermal vent protistan distribution along the Mariana arc suggests vent endemics may be rare and novel

“…The 2014 expedition was more limited in scope but included revisiting sites along the arc that had not been sampled since 2006, sampling one additional site on the back-arc (Urashima), and returning to NW Rota-1 (Supporting Information Fig. S2) to find greatly decreased volcanic activity relative to all prior visits in the previous decade (Schnur et al, 2017).…”

Exploring the Ecology of Deep-Sea Hydrothermal Vents in a Metacommunity Framework

“…For example, at the fast-spreading EPR, vent communities have been observed to be eradicated by seafloor eruptions on decadal time scales (Rubin et al, 2012), but at the slow-spreading MAR an eruption might not occur for 10,000 years (Perfit and Chadwick, 1998). Some arc volcanoes "grow and collapse on human timescales" due to frequent eruptions as well as landslides (Schnur et al, 2017). Other non-volcanic natural disturbances, such as earthquake activity or cessation of a vent within the patch, may lead to minor to moderate disturbances that affect patch size or quality.…”

“…Disturbance may also create new habitat. The frequency of disturbance may range from almost continuous at vents on submarine arc volcanoes with multiyear eruptions (e.g., NW Rota-1; Rubin et al, 2012;Schnur et al, 2017) to very infrequent at vents hosted in ultraslow spreading settings. At spreading ridges, the frequency of volcanic eruptions is related to timeaveraged magma supply and spreading rate (Perfit and Chadwick, 1998).…”