volcanic neck

Technically, a volcanic neck is the open tunnel through which an active volcano releases molten rock, ash, and gases from deep in the Earth. In common usage, however, neck is sometimes used (as is volcanic plug) to describe the column of solidified lava that hardens in this opening once the eruption is over—a stone column that may be exposed by subsequent erosion. In the stricter definition, one might say that a volcanic neck is a filled volcanic pipe, a pipe an active neck. Notable volcanic necks include Huérfano Butte in Colorado, Agathla Peak in northeastern Arizona, and Cabezon Peak in northwestern New Mexico.

Kim Stafford