The Quantum Gravimeter Network of the Canary Islands

The island of Tenerife (Canary Islands) exhibits the highest volcanic risk in Spain, owing to its long volcanic history combined with high population density. Consequently, an effective volcanic early-warning system is essential to ensure the safety of both the island’s residents and the millions of tourists who visit each year. Tenerife already hosts one of the most advanced volcano monitoring programs worldwide, integrating permanent instrumental networks with periodic geophysical and geochemical surveys.Continuous microgravity measurements have proven to be a sensitive and reliable tool for detecting changes in magmatic–hydrothermal systems that may remain undetected by other geophysical or geochemical techniques [1]. However, spring-based gravimeters are affected by instrumental drift, which can compromise the interpretation of long-term observations. Superconducting gravimeters, while offering the highest sensitivity, require complex liquid helium refrigeration systems, significantly limiting their operational deployment. In recent years, absolute quantum gravimeters have emerged as the state-of-the-art technology for microgravity monitoring [2]. Time series acquired at active volcanoes, such as Mount Etna [3], demonstrate that these instruments can detect and quantify subsurface mass redistributions associated with volcanic processes. Within the framework of the GEOFIS-CAN project, the Instituto Volcanológico de Canarias (INVOLCAN) has acquired three Exail AQG-A absolute quantum gravimeters to be deployed on Tenerife.The volcanic system of Tenerife consists of a central caldera (Las Cañadas), which hosts the Teide–Pico Viejo volcanic complex and is characterized by both basaltic and phonolitic activity, and three radial dorsals dominated by fissural basaltic effusive eruptions. The central complex, as well as the northwestern (NW) and northeastern (NE) dorsals, have experienced eruptions within the last 500 years. The three AQG instruments will be installed at: (1) the NW dorsal (Santiago del Teide), the most volcanically active sector of the island; (2) the boundary between the Las Cañadas caldera and the NE dorsal (Izaña); and (3) the southern margin of the caldera (Vilaflor). This network geometry provides comprehensive coverage of all regions potentially affected by future eruptions. Moreover, it enables not only the detection but also the localization of subsurface mass changes within the volcanic edifice. Specifically, this configuration is sufficient to simultaneously and unambiguously constrain both the location and magnitude of the mass variations within the volcanic edifice.In this work, we present a sensitivity analysis of the proposed gravimetric network configuration, together with preliminary results from the recorded dataset. References[1] de Zeeuw-van Dalfsen, E., & Poland, M. P. (2023). Microgravity as a tool for eruption forecasting. Journal of Volcanology and Geothermal Research, 442, 107910.[2] Ménoret, V., Vermeulen, P., Le Moigne, N., Bonvalot, S., Bouyer, P., Landragin, A., & Desruelle, B. (2018). Gravity measurements below 10− 9 g with a transportable absolute quantum gravimeter. Scientific reports, 8(1), 12300.[3] Antoni‐Micollier, L., Carbone, D., Ménoret, V., Lautier‐Gaud, J., King, T., Greco, F., ... & Desruelle, B. (2022). Detecting volcano‐related underground mass changes with a quantum gravimeter. Geophysical Research Letters, 49(13), e2022GL097814.