A two-mile volcanic fissure in Oregon’s high desert, Crack in the Ground formed when eruptions from the nearby Four Craters lava field emptied an underground magma chamber, causing the ground surface to fracture and drop. Located within the High Lava Plains geologic province of Lake County, the fissure reaches seventy feet in depth and in places is only an arms width across. A rare and accessible example of volcanic rift geology in the American West.