Anelastic response of the Earth's crust underneath the Canary Islands revealed from ocean tide loading observations

Summary We report on the analysis of M2 ocean tide loading (OTL) kinematic GPS vertical displacement and tidal gravity measurements using 26 four gravimetric sites across Canary Islands archipelago. In this region, standard deviation among recent models is lower than 0.4 cm in amplitude 0.3 degrees phase, which are suitably accurate for modelling. However, we need to model regional tides achieve enough accuracy calculations. Particularly, study improves predicted OTL variations when global replaced with CIAM2 assimilates local gauge data. These small errors allow us use differences between observed values elastic anelastic properties solid Earth around Islands. prediction OTL, first used STW105 S362ANI seismic models, obtaining average minus residuals 1.2–1.3 mm 3 nms−2 gravity. After were adjusted anelasticity, by considering a constant quality factor Q at periods ranging from 1 s 12.42 hours, misfit observations reduced 0.7–0.8 made up site misfits less 0.5 western islands but easternmost Lanzarote Fuerteventura, they still reach nearly 2 some sites, exceeds uncertainty observations. It hypothesised that mantle upwelling underneath Islands, creating spatial properties, causes large eastern islands. shear modulus 35 per cent upper layer 24.4−220 km depth. This produced residual about 0.7 comparable results obtained rest archipelago, whose turn also slightly through Vs velocity reductions (by 0.2 average).