In this paper, ultraviolet photoelectron spectroscopy (UPS) and metastable impact electron spectroscopy (MIES) results are reported for water adsorption on SiO2/Mo(112) surfaces. It is shown that UPS spectra are insufficient for the determination of the detailed mechanism for water dissociation. By use of UPS in combination with MIES, however, it is shown that multilayer-induced dissociation is responsible for hydroxyl group formation. It is suggested that hydroxyl groups on oxide surfaces can be stabilized by neighboring water molecules (solvation), even when the interaction between the hydroxyl groups and the surface is weak. These results demonstrate that simultaneous UPS and MIES measurements offer a powerful methodology for the investigation of multilayer-induced reactions which have important implications at the liquid-solid interface.