Schoch is best known for his fringe argument that the Great Sphinx of Giza is much older than conventionally thought and that possibly some kind of catastrophe was responsible for wiping out evidence of a significantly older civilization. In 1991, Schoch redated the famous monument to 10,000–5,000 BC, based on his argument that its erosion was due mainly to the effects of water, rather than wind and sand, and also based on findings from seismic studies around the base of the Sphinx and elsewhere on the plateau.[6][7][8] These conclusions do not have consensus in the scientific community.