A general viscosity model of Campi Flegrei (Italy) melts

► Viscosities of shoshonitic and latitic melts relevant to the Campi Flegrei caldera magmas have been measured. ► Micropenetration, concentric cylinder and falling sphere were adopted to determine viscosity of dry and hydrous melts. ► The combination of experimental data allowed us create a general model of viscosity using the modified VFT equation. ► The proposed model has been applied to Campi Flegrei products.►Viscosity data have been used to constrain the ascent velocity of melts within dikes.