Local Earthquake Seismic Tomography Reveals the Link Between Crustal Structure and Volcanism in Tenerife (Canary Islands)
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Wiley
Fecha
2023-03-10Referencia bibliográfica
Koulakov, I., D'Auria, L., Prudencio, J., Cabrera‐Pérez, I., Barrancos, J., Padilla, G. D., ... & Ibáñez, J. M. (2023). Local earthquake seismic tomography reveals the link between crustal structure and volcanism in Tenerife (Canary Islands). Journal of Geophysical Research: Solid Earth, 128(3), e2022JB025798.
Patrocinador
Russian Science Foundation (Grant 20-17-00075); INVOLCAN team was supported by the projects VOLRISKMAC II (MAC2/3.5b/328) and co-financed by the Interreg-MAC EU program TFvolcano projects, financed by the Instituto Tecnológico y de Energías Renovables (ITER); Spanish FEMALE project (PID2019-106260GB-I00) and PROOF-FOREVER project; Project FWZZ- 2022.0017; Funding for open access charge: Universidad de Granada/CBUAResumen
Volcanic activity on Tenerife Island is extremely diverse. Three radial rift zones are
characterized by cinder cones from basaltic fissure eruptions. A triple junction in central Tenerife exhibits
a complex of merged, predominantly phonolitic, stratovolcanoes. The Las Cañadas caldera and widespread
ignimbrite deposits reveal high explosive potential. We investigated the crustal and upper mantle structure
beneath Tenerife using local earthquake data recorded by two dense seismic networks on the island. For our
tomographic inversion, we selected >130,000 P- and S-wave arrivals from ∼6,300 events that occurred during
seismic unrests in 2004–2005 and 2017–2021. Synthetic tests confirmed that we could robustly resolve seismic
velocity structures to ∼20 km depth. In the upper crust (down to ∼7 km) beneath central Tenerife, a prominent
high-velocity anomaly represents the rigid core of the volcanic complex; at greater depths, a strong low-velocity
anomaly reveals abrupt crustal thickening. Vp and Vs contour lines of 5.2 and 2.85 km/s, respectively, reveal
Moho depth variation; crustal thickness beneath Las Cañadas reaches ∼17 km, whereas that beneath other parts
of Tenerife is ∼10 km. An anomaly at ∼5 km beneath the caldera with low Vp, low Vs, and high Vp/Vs might
be associated with a major phonolitic magma reservoir. Similar anomalies at ∼ sea level may represent shallow
magma sources responsible for recent eruptions. Seismicity occurs in a columnar area of high Vp, high Vs, and
low Vp/Vs, and may represent hydrothermal fluid migration through brittle media. Based on our results, we
constructed a conceptual model of volcanic activity on Tenerife.