Evidence of a Low-Velocity Zone in the Upper Mantle Beneath Cumbre Vieja Volcano (Canary Islands) Through Receiver Functions Analysis

Abstract

Oceanic volcanic islands have a complex internal structure due to their geological evolution. La Palma is the second youngest in the Canary Islands. Historical eruptions occurred in the Cumbre Vieja (CV) volcanic system, including the last 2021 Tajogaite eruption. The seismicity before, during, and after the Tajogaite eruption provides valuable information for a better understanding of deep volcanic processes. We applied the receiver function technique to image the crustal and upper mantle structures beneath the CV volcanic complex. We investigated the first 50 km of the lithosphere, identifying various seismic discontinuities. After a thin layer of recent volcanic rocks, we found a layer corresponding to the old oceanic crust. Beneath the Moho, we found a significant decrease in the seismic velocities until about 37 km of depth. This low-velocity layer corresponds to a zone of partial melting with interconnected magmatic chambers that feed the volcanic activity in CV.