Volcanic Events in Craters of the Moon National Monument, USA43.4N 113.5W
Craters of the Moon National Monument, in Idaho, visible here as an upside-down V-shaped brown area on the right side of the image, is a vast ocean of lava flows with scattered islands of cinder cones and sagebrush. Volcanic events were reported in the area on June 15th, and are expected to continue today.
Between 15,000 and 2,000 years ago, the Craters of the Moon Lava Field formed during eight major eruptive periods. During this time the Craters of the Moon lava field grew to cover 618 square miles. The Wapi and Kings Bowl lava fields formed contemporaneously about 2,200 years ago.
Currently, this region is experiencing basin and range type faulting, which is stretching or pulling apart the crust. The Lost River Range north of the town of Arco provides good evidence that these forces are still active. In 1983 these forces caused a magnitude 6.9 earthquake, during which Mount Borah rose about 1 foot and the Lost River Valley in that vicinity dropped about 8 feet.
On the Eastern Snake River Plain, rather than producing mountain ranges, the tensional forces have caused decompression melting, which results in dike emplacement and periodic eruption of molten rock onto the surface. As long as these forces continue to act, more eruptions will occur.