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

• Published in: Journal of geophysical research. Solid earth Vol. 122; no. 3; pp. 1558 - 1584
• Main Authors: Schnur, Susan R., Chadwick, William W., Embley, Robert W., Ferrini, Vicki L., Ronde, Cornel E. J., Cashman, Katharine V., Deardorff, Nicholas D., Merle, Susan G., Dziak, Robert P., Haxel, Joe H., Matsumoto, Haru
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01-03-2017
• Subjects: Arc volcanoes; Bathymetric surveys; Bathymetry; Cliffs; Collapse; Construction; Debris; Debris cone; Destruction; Distribution; Energy; Eruptions; Evolution; Extrusion; Geologic mapping; Geological mapping; Geological surveys; Geology; Geophysics; Growth; High resolution; Hydrophones; hydrothermal systems; Landslides; Landslides & mudslides; Lava; Lava flows; Lithofacies; Mapping; Mass wasting; NW Rota‐1; Outcrops; Pebbles; Remotely operated vehicles; Seamounts; subaqueous volcanism; Subduction; Subduction (geology); Subduction zones; submarine volcanism; Surveys; Tephra; Underwater vehicles; Vents; Videography; Volcanic activity; Volcanic eruption effects; Volcanic eruptions; volcanic lithofacies; Volcanism; Volcanoes; ISEW, Pacific, Mariana Arc
• ISSN: 2169-9313; 2169-9356
• DOI: 10.1002/2016JB013742

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.
Key Points
Repeat bathymetric mapping, ROV observations, and hydrophone records document changes in geology and eruptive style at NW Rota‐1 seamount
Changes in eruptive activity between 2009 and 2010 impacted the type and distribution of geologic lithofacies at the summit of NW Rota‐1
Landslides are important agents of change at submarine arc volcanoes, and their frequency is controlled by cyclic eruptive activity