The elevation crater theory is a now-discredited[citation needed] geologic theory originating in the 18th and 19th centuries which intended to explain the origin of mountains and orogens, holding that mountains formed by vertical movements associated with volcanism.
[2] Humbold and Buch considered basaltic volcanism to be linked to elevation craters and trachyte to be the product of "true volcanoes".
[3] Otto Wilhelm Hermann von Abich applied the theory to the Caucasus Mountains and, following the views of Buch and Humboldt, linked mountain building to volcanism, which led him to take interest in the volcanoes of the Caucasus in the area.
Working in the Alps, he considered the mountains to be roughly symmetrical with a Mittelzone ('middle area') containing the igneous rocks that he believed had uplifted them.
[2] The theory, as posited by Studer, was popular among geologists in Switzerland and nearby areas until the 1870s.