A scientific collaboration between researchers from the Trofimuk Institute of Petroleum Geology and Geophysics of Novosibirsk in Russia, the Volcanological Institute of the Canary Islands (INVOLCAN) and the University of Granada (UGR) has revealed the secrets of the interior of the island of Tenerife through a new seismic tomography study, analyzing for this the microseismicity located in the interior of the island.
The results of this study can be considered amazing, because it is the first time that scientists have been able to visualize and characterize a hot heart of magma under the island of Tenerife, located less than 10 kilometers deep from the mouth of the Teide volcano. , which could be a precursor sign of an eruptive process in it.
The tomography clearly shows that, in the crust below the Las Cañadas caldera, the presence of small magmatic reservoirs at depths of less than 5 kilometers is possible. These reservoirs allow the magma to cool, changing its chemical composition towards phonolite, a potentially explosive type of magma. These magmatic reservoirs may be the source of highly explosive eruptions such as the one that occurred at the Montaña Blanca volcano around 2,000 years ago and which was of the sub-Plinian type.
The authors of the new study present a possible explanation for why the eruptions in Tenerife that occur outside the Las Cañadas caldera, along the NE and NW ridges, have a more effusive character, not being able to magma stagnate long enough to evolve into a more explosive type.
The results of this study have been published in the Journal of Geophysical Research, (March 21, 2023) one of the most relevant international scientific journals in the field of geophysics published by the American Geophysical Society (AGU). These results constitute an important tool for interpreting the increase in seismicity in Tenerife and the emission of carbon dioxide from the Teide crater, which INVOLCAN has detected since the end of 2016. This activity could be related to the slow ascent of a diapir. , say a "bubble" of magma, at depths greater than 10 kilometers below Teide. Therefore, this new knowledge will be of great use for a better interpretation of the precursor signals of a possible eruptive process in Tenerife.
This seismic tomography study has been possible as a result of the launch in 2016 of the Canary Islands Seismic Network managed by the Canary Islands Volcanological Institute (INVOLCAN) and which currently has 19 broadband seismic stations that have allowed downloading the ability to detect and locate thousands of micro-earthquakes in Tenerife. These data, together with those previously recorded by the National Geographic Institute (IGN), have made it possible to use seismic tomography to investigate the interior of the island up to a depth of 20 kilometers and, even more important, to determine the speed of the seismic S waves. , which are the most sensitive to the presence of hydrothermal fluids and magma.
Prior to this recent seismic tomography study, another international scientific collaboration led by the University of Gradada managed to obtain the first three-dimensional model of the island of Tenerife in 2012. For the execution of this scientific collaboration work, the oceanographic vessel R/V Hespérides from which 6459 shots were made, which were recorded by a network made up of 125 seismic stations. This active seismic experiment allowed to investigate the interior of the island up to a depth of 10 kilometers and, due to the nature of the artificial seismic source, it was only possible to obtain a velocity model of the P seismic waves.
The results of this new international scientific collaboration work published in 2023 have been possible thanks to the VOLRISKMAC II projects (MAC2/3.5b/328), co-financed by the European Commission through the INTERREG MAC Territorial Cooperation Program 2014-2020, TFvolcano, funded by the Instituto Tecnológico y de Energías Renovables (ITER) and the Cabildo Insular de Tenerife, FEMALE (PID2019-106260GB-I00) and PROOF-FOREVER as well as the projects of the Russian Science Foundation (Grant No. 20-17- 00075 and Project FWZZ-2022-0017).
Bibliographic reference:
Ivan Koulakov, Luca D'Auria, Janire Prudencio, Ivan Cabrera-Perez, Jose Barrancos, Germon D. Padilla, Nemesio M. Perez, Jesus M. Ibanez. Local earthquake seismic tomography reveals the link between crustal structure and volcanism in Tenerife (Canary Islands). Journal of Geophysical Research-Solid Earth [https://doi.org/10.1029/2022JB025798]
