After the Irpinia earthquake in 1980 caused further weakening of Pompeii's crumbling walls, systematic initiatives were put into place to evaluate the damage. The excavation team took documentary photographs, conducted a systematic survey, and recorded the qualitative data through a computer processing system. From these findings, Mariette de Vos calculated that the number of existing paintings made up only ten percent of what was originally found in earlier excavations, while another ten percent was only known through drawings and photos. For the first time, the team was able to show that Pompeii had indeed been over-excavated, and provide a comprehensive view of how, where, and to what extent conservation and restoration was needed.