We considered the Vp tomographic model of Seccia et al. (2011) for Long Valley Caldera on which we applied the Horizontal Gradient technique for retrieving geometrical information about the deep structures characterizing the first 10 km of crust. Specifically, after the regularization through spatial based kriging interpolator, we compute the horizontal derivatives on single z-layers with sampling step of 500 m. The results are presented in Gola G., Barone A., Castaldo R., Chiodini G., D'Auria L., Garcia-Hernandez R., Pepe S., Solaro G. & Tizzani P. "A novel multidisciplinary approach for the thermo-rheological study of volcanic areas: The case study of Long Valley Caldera", which has been submitted for possible publication in Journal of Geophysical Research - Solid Earth. Coordinates: North America NAD27 UTM Zone 11N Easting: 308000 - 353000 m.; Northing: 4155000 - 4185000 m; XY resolution: 500 m.