Valles Caldera in the Jemez Mountains, New Mexico USA – January 31st, 201035.9N 106.5W
Valles Caldera (or Jemez Caldera), is a 12-mile-wide collapsed volcanic caldera in the Jemez Mountains of northern New Mexico, visible as a circular area towards the center of this orthorectified image. It is part of the Valles Caldera National Preserve, created on July 25th, 2000. The preserve has a land area of 89,716 acres (140.18 sq mi, or 363.07 km2), and is located in northeastern Sandoval County and southern Rio Arriba County, just west of Los Alamos.
Valles Caldera is one of the smaller volcanoes in the supervolcano class. The circular topographic rim of the caldera measures 19 kilometers (12 miles) in diameter. The caldera and surrounding volcanic structures are the most thoroughly studied caldera complex in the United States.
The Valles Caldera is the younger of two calderas known at this location, having collapsed over and buried the Toledo Caldera, which in turn may have collapsed over yet older calderas. The associated Cerros del Rio volcanic field, which forms the eastern Pajarito Plateau and the Caja del Rio, is older than the Toledo Caldera. These two large calderas formed during eruptions 1.47 million and 1.15 million years ago. The caldera and surrounding area continue to be shaped by ongoing volcanic activity.