EGU2020-11456, updated on 20 Jan 2021
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Groundwater and soil CO2 efflux weekly monitoring network for the surveillance of Cumbre Vieja volcano, Canary Islands

Cecilia Amonte1, Alana Mulliss2, Elizabeth Sampson3, Alba Martín-Lorenzo1,4, Claudia Rodríguez-Pérez1, Daniel Di Nardo1,4, Gladys V. Melián1,4,5, José M. Santana-dLeón1, Pedro A. Hernández1,4,5, and Nemesio M. Pérez1,4,5
Cecilia Amonte et al.
  • 1Instituto Volcanológico de Canarias (INVOLCAN), 38240 La Laguna, Tenerife, Canary Islands, Spain (
  • 2Faculty of Engineering, Environment and Computing, Coventry University, 3Coventry, CV1 5FB, U.K.
  • 3Department of Geological Sciences, Ohio University, Athens, OH 4570, U.S.A
  • 4Instituto Tecnológico y de Energías Renovables (ITER), 38611 Granadilla de Abona, Tenerife, Canary Islands, Spain
  • 5Agencia Insular de la Energía de Tenerife (AIET), 38611 Granadilla de Abona, Tenerife, Canary Islands, Spain.

La Palma Island (708.32 km2) is located at the north-western end of the Canary Archipelago and is one of the youngest of the archipelago. In the last 123 ka, volcanic activity has taken place exclusively at Cumbre Vieja, the most active basaltic volcano in the Canaries, which is located at the southern part of the island. Since no visible geothermal manifestations occur at the surface environment of this volcano, during the last 20 years there has been considerable interest in the study of diffuse degassing as a powerful tool in the volcano monitoring program. In this study we have used two different geochemical approaches for volcano monitoring from October 2017 to November 2019. First, we have developed a network of 21 closed static chambers to determine soil CO2 effluxes. Additionally, we have monitored physical-chemical parameters (temperature, pH, electrical conductivity -EC-) and chemical/isotopic composition and dissolved gases in the water of two galleries (Peña Horeb and Trasvase Oeste) and one water well (Las Salinas). Soil CO2 effluxes for the alkaline traps showed an average value of 7.4 g·m-2·d-1 for the entire Cumbre Vieja volcano. The gas sampled on the head space of the traps can be considered as CO2-enriched air, showing an average value of 1,942 ppmV of CO2. Regarding the CO2 isotopic composition (δ13C-CO2), most of the stations exhibited CO2 composed by different mixing degrees between atmospheric and biogenic CO2 with slight contributions of deep-seated CO2, with an average value of -19.3‰. The results of the physical-chemical parameters measured in waters showed mean temperature values of 23.7ºC, 19.6ºC and 22.1ºC, 7.40, 6.27 and 6.60 for the pH and 1,710 µS·cm-1, 411 µS·cm-1 and 41,100 µS·cm-1 for the EC, for Peña Horeb, Trasvase Oeste and Las Salinas, respectively. The δ13C-CO2 composition of the dissolved gas has a mean value of -7.8‰, -10.2‰ and -3.8‰ vs. VPDB for Peña Horeb, Trasvase Oeste and Salinas, respectively. The highest values of CO2 efflux coincided with the stations showing highest CO2 concentration values located at the southern end of Cumbre Vieja, where the most recent volcanic eruption took place, and also on the northwest flank. This is in accordance with the results obtained for Las Salinas well, located in the south of the island, which show a high concentration of dissolved CO2 and δ13C-CO2 values with a strong deep-seated CO2 contribution. This study represents an interesting contribution to detect early warning signals of future unrest episodes at Cumbre Vieja.

How to cite: Amonte, C., Mulliss, A., Sampson, E., Martín-Lorenzo, A., Rodríguez-Pérez, C., Di Nardo, D., Melián, G. V., Santana-dLeón, J. M., Hernández, P. A., and Pérez, N. M.: Groundwater and soil CO2 efflux weekly monitoring network for the surveillance of Cumbre Vieja volcano, Canary Islands, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11456,, 2020