Crack in the Ground is a great geologic feature to visit in Central Oregon . It is a volcanic fissure over two miles long and up to 70 feet deep. The crack was estimated to have been formed about 1000 years ago. It is the result of a tension fracture along a hinge line produced by the draping of Green Mountain lava flows over the edge of up thrown side of the concealed fault zone. The time that the crack has been open is unusual. Most cracks that form from lava flow fill up with sediment fairly quickly. This is due to the arid conditions of the area where it is located. You can find it 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.
It is a great place to take kids and pets. There are very few steep spots and most of the fissure is level with a path running down the middle. For those that are more adventurous there are sections of the fissure that you can climb down into and there is a small cave system you can explore.
