Crack in the Ground is a volcanic fissure about long with depths measuring nearly below ground level in

Central Oregon Central Oregon is a geographic region in the U.S. state of Oregon and is traditionally considered to be made up of Deschutes, Jefferson, and Crook counties. Other definitions include larger areas, often encompassing areas to the north towards ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

. The formation of the fissure occurred approximately between 700,000 and 12,000 years ago. The eruptions from the Four Craters Lava Field were accompanied by a slight sinking of the older rock surface, forming a shallow,

graben In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...

-like structure about wide and extending to the south into an old lake basin. Crack in the Ground marks the western edge of this small, volcano-tectonic depression. The crack is the result of a tension fracture along a hingeline produced by the draping of Green Mountain lava flows over the edge of upthrown side of the concealed fault zone. The fissure is located at the southwest corner of Four Craters Lava Field. Hikers can walk the length of the main crack and explore its tributaries.

References

Geology of Oregon Fissure vents Landforms of Lake County, Oregon Deschutes National Forest Protected areas of Lake County, Oregon {{LakeCountyOR-geo-stub

See also

References