Open AccessEvolution of submarine eruptive activity during the 2011–2012 E l H ierro event as documented by hydroacoustic images and remotely operated vehicle observations
Author(s) -
Somoza L.,
González F. J.,
Barker S. J.,
Madureira P.,
Medialdea T.,
de Ignacio C.,
Lourenço N.,
León R.,
Vázquez J. T.,
Palomino D.
Publication year - 2017
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1002/2016gc006733
Subject(s) - geology , lava , submarine volcano , volcano , lapilli , pyroclastic rock , explosive eruption , submarine , effusive eruption , lava dome , seismology , volcanic cone , geochemistry , magma , impact crater , submarine landslide , strombolian eruption , petrology , oceanography , astrobiology , physics
Abstract Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high‐density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.