- Crack in the Ground
Crack in the Ground is a volcanic fissure over two miles (3 km) long and up to 70 feet (21 m) deep in central Oregon, US. The eruptions from the Four Craters Lava Field were accompanied by a slight sinking of the older rock surface, forming a shallow, graben-like structure about 3 kilometers 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. It is located in the southwest corner of Four Craters Lava Field in the Deschutes National Forest. Hikers can walk the length of the main crack and explore its tributaries.
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