Satellite surface deformation survey reveals evidence for active magmatic processes at the Tibesti (Africa) continental intraplate volcanoes

Abstract Intraplate magmatic activity within continental lithosphere remains less explored than its oceanic counterpart. Here, we present the first satellite-based survey of volcano surface deformation across the Tibesti volcanic province in North Africa. Sentinel-1 Interferometric Synthetic Aperture Radar time series (2017–2021) reveal overall stability across its eight major volcanic centers, but two areas exhibit broad and persistent subsidence. At the Toussidé–Yirrigué complex, we detect − 2.2 ± 0.3 mm/yr subsidence from a contracting source at 7.6 ± 0.8 km depth. A faster rate of − 8.5 ± 0.3 mm/yr occurs at the Soborom geothermal field on the Voon caldera northeastern flank, linked to a source at 4.9 ± 0.1 km depth. Apparent uplift at Trou au Natron and Era Kohor is attributed to non-magmatic, moisture-driven artifacts over saline surfaces. Geodetic models, constraining source geometry and contraction rates, are consistent with petrological thermobarometry estimates for magma storage depths. Thermodynamic modeling of Tibesti’s trachy-andesitic magmas indicates that crystallization, enhanced by volatile exsolution, can qualitatively account for the observed subsidence. Simple mechanical cooling models suggest that subsidence could be the result of protracted thermoelastic and/or visco-thermoelastic relaxation of mid-crust emplaced magma bodies. These findings provide the first geodetic evidence of active magmatic processes at the Tibesti volcanoes, possibly due to long-term cooling and crystallization of magma reservoirs during the Holocene.