Benefits and Limitations of the Growth Inversion Approach in Volcano Gravimetry Demonstrated on the Revisited 2004–2005 Tenerife Unrest

Abstract

Abstract We review the current geoscientific knowledge of the volcanic unrest of 2004–2005 on Tenerife (Canary Islands) and revisit its gravimetric imprint. We revise the interpretation of the observed spatiotemporal (time-lapse) gravity changes accompanying the unrest by applying the Growth inversion approach based on model exploration and free geometry growing source bodies. We interpret the Growth solution, our new gravimetric model of the unrest, in the context of structural controls and the existing volcanological and geological knowledge of the central volcanic complex (CVC) of the island. Structural controls are inferred from the updated structural subsurface CVC density model obtained by our new Growth inversion of the available complete Bouguer anomalies (CBA data). Our gravimetric picture sees the unrest as a failed eruption, due to a stalled magma intrusion in the central position below the Teide–Pico Viejo stratocones, followed by upward and lateral migration of volcanic fluids reaching the aquifer and the SW end of the caldera wall. We thus classify the volcanic unrest of 2004–2005 as hybrid, in agreement with previous studies. The Growth inversion indicates that magma propagated along the boundary between the basaltic core of the island, the Boca Tauce volcanic body and the more permeable (less compacted) volcanic rocks with lower density. This gravimetric picture of the unrest provides new insights into the potential future reactivation of the volcanic system. Article Highlights Current geoscientific knowledge of the Tenerife volcanic unrest of 2004–2005 is reviewed New insights into the unrest are yielded by Growth inversion of observed time-lapse gravity changes Role of the freely adjustable inversion parameters in the Growth methodology is demonstrated Pros and cons of the Growth inversion approach in volcano gravimetric applications are illustrated