Juan-Tomás Vazquez

Submarine volcanism in the Canary Islands in the 21st century

In the 21st century there have been two volcanic eruptions in the Canary Islands, the first took place in the southwestern flank of the island of El Hierro, between October 2011 and March 2012, which gave rise to the Tagoro volcano developed in an environment submarine and, the second occurred in the western part of the Cumbre Vieja volcanic ridge on the island of La Palma, between September and December 2021, although the lava flows from this volcanic eruption reached the marine domains and affected the seabed of the insular shelf and slope. The Spanish Institute of Oceanography (IEO, CSIC) has monitored the geological processes and the morphological changes of the seabed associated with the active stage of these two eruptions, as well as the physical-chemical and biological changes in the water column and on the marine ecosystems. In addition, once the eruption ended, the post-eruptive evolution of these volcanic systems has continued monitored by the IEO-CSIC, studying hydrothermal emissions as well as their effects on the water column properties and marine ecosystems. The eruption of the Tagoro volcano gave rise to the formation of an asymmetric volcanic cone on the slope of the El Hierro island, built mainly by pyroclastic emissions and lava balloons accumulations, although the presence of pillow lavas has also been recognized and a mixed flow was generated favor of the slope formed by volcanoclastic materials and rock debris generated by the landslides triggered by the eruption and by the collapses that the volcanic cone suffered during its evolution. In the 2021 La Palma eruption, an important volcanic cone grew up around the emission vent centers, characterized by an accumulation of ash and pyroclastic materials. In addition, it gave rise to important fields of lava flows. These lava flows normally reached the sea as “aa” type and generate two lava deltas that occupied practically the entire insular shelf. Upon reaching the shelf border, these lava flows were channeled along several submarine gullies present in the upper slope, which has given rise to a prism-shaped accumulation that reaches a depth of 300 m, generating both lava block fields and hollow-pillow lavas. The possibility of monitoring these two eruptions in the marine environment has allowed us to better understand not only the development of volcanic processes in the marine environment, but also the interaction between magmatic processes and the water column anomalies and the recovery processes of the marine ecosystems.