Diffuse CO2 and H2S degassing from Tajogaite volcanic cone, La Palma, Canary Islands

Abstract

La Palma Island (708 km2) is located at the north-west and is one of the youngest (~2.0My) of the Canarian Archipelago. The current stage of shield-building is manifest by the construction of Cumbre Vieja volcano, at the southern part of the island, where volcanic activity has taken place exclusively in the last 123 ka. On September 19, 2021, a new volcanic eruption occurred at Cumbre Vieja volcanic system (Tajogaite eruption). The erupting fissure (~1.0 km-length) is characterized by lava effusion, strombolian activity, lava fountaining, ash venting and gas jetting. After 85 days, the eruption finished on December 13, 2021. The 2021 Tajogaite eruption, with a magnitude VEI=3 (Bonadonna et al., 2022), resulted in the longest volcanic event on the island during the last 600 years and the most important eruption of Europe during the last 75 years.At the time of this study, the volcanic gas emissions observed at Tajogaite volcanic cone consisted mostly in diffuse CO2 degassing and residual fumarolic activity. Here we report the first diffuse CO2 and H2S emission surveys that have been carried out in Tajogaite volcanic cone.The measurements of soil CO2 efflux have been performed following the accumulation chamber method in 94 sites and the spatial distribution maps have been constructed following the sequential Gaussian simulation (sGs) procedure to show the location of CO2 and H2S diffuse degassing structures (DDS) and to quantify the diffuse CO2 and H2S emission from the studied area. The diffuse CO2 emission released to the atmosphere from Tajogaite volcanic cone ranged between 0 to 11.4 kgm-2·d-1 with an average of 0.90 kgm-2·d-1. The main DDS was located in the easternmost area of ​​the cone. Regarding the diffuse H2S emission, the data ranged between 0 to 44. 7 kgm-2·d-1 with an average value of 3.0 kgm-2·d-1. Two main DDS were identified: one coinciding with the CO2 DDS, in the easternmost zone, and other in the northern area of the cone. This study represents a starting point to study the degassing of the residual magma bodies beneath Tajogaite volcanic cone.Bonadonna, C. et al. (2022), EGU22-11927, https://doi.org/10.5194/egusphere-egu22-11927.