A Toreva block
landslide is a distinctive landslide
type which may occur when a stronger material such as sandstone or limestone overlies a weaker material such as shale
and an eroding agent undercuts the weaker lower layer. The type was first recognized by Parry Reiche
in 1937, and takes its name from Toreva, Arizona
. Toreva blocks exhibit a characteristic backward rotation toward the parent cliff.
The existence of Toreva blocks may be used to infer a warmer or wetter earlier climate, e.g. toreva blocks in the Transantarctic Mountains.