A scientific study has reconstructed the deep structure of Tenerife in 3D for the first time and identified several areas of low seismic velocity that might be linked to magma presence. The main anomaly lies beneath the island’s western region, extending from approximately 10 to 30 kilometres deep.
Led by Víctor Ortega-Ramos from the Volcanological Institute of the Canary Islands (INVOLCAN) and a doctoral candidate at the Complutense University of Madrid (UCM), the research analysed over 785 earthquakes recorded by the Canary Seismic Network between 2017 and 2024.
The findings, published in Scientific Reports, provide a new perspective on Tenerife’s deep magmatic system and how it connects to surface seismicity and gas emissions.
The study created a 3D model of seismic wave speeds down to about 50 kilometres. Researchers identified a roughly 10-kilometre-thick layer of oceanic crust characterised by relatively high seismic speeds. Beneath this is a more heterogeneous layer, featuring four significant low-velocity anomalies.
These anomalies may be linked to high temperatures or alterations in the composition and physical properties of the rocks. The team combined seismic data with petrological information and thermodynamic models to estimate the amount of molten material present, finding local fractions of magma as high as 79% by weight.
Importantly, this does not indicate a single massive magma chamber under Tenerife but suggests different deep anomalies, some potentially associated with magma accumulations.
The primary anomaly is specifically located beneath western Tenerife, interpreted as a zone rich in molten material within the upper mantle. Researchers hypothesise that magma may gradually accumulate at the base of the oceanic crust from deeper sources.
This process, known as magmatic underplating, could have shaped the physical and chemical characteristics of Tenerife’s deeper regions as it evolved. The study supports the idea of an active underplating process and provides new insights into Tenerife’s magmatic feeding system.
The research also found a spatial correlation between the deep anomalies and some recorded seismic activity on the island. Earthquake clusters mainly occurred above or at the edges of these low-velocity zones, suggesting insights into magma accumulation, gas emissions, and the injection of magmatic volatiles into the hydrothermal system.
As magma rises to shallower depths, the reduction in pressure can cause dissolved gases, particularly carbon dioxide (CO₂), to separate from the molten material. The movement of these fluids could partly explain the observed seismicity, including hybrid and low-frequency events.
The study offers a more comprehensive view of Tenerife’s magmatic system, allowing for a simultaneous observation of the crust and upper mantle structure. Researchers used receiver function techniques to evaluate how seismic waves change as they pass through different inner Earth structures.
By analysing over 785 tele-seisms recorded over seven years, they constructed this 3D representation and pinpointed key discontinuities and anomalies beneath the island.
Future research will need to better ascertain the geometry, extent, and connections of these deep zones, requiring a combination of seismic data with other geophysical, petrological, and geochemical techniques.
The goal is to gain a clearer understanding of how magma stores, accumulates, and transfers beneath Tenerife, and how these processes relate to the parameters used in volcanic monitoring.
The study does not predict an eruption for Tenerife but significantly enhances understanding of the island’s deep structure, contributing valuable information for volcanic system monitoring and risk assessment.
