How can I tell if I have found an impact crater?
There are many natural processes other than impacts that can create circular features and depressions on the surface of the Earth. Examples include glaciation, volcanism, sinkholes, atolls, salt domes, intrusions, and hydrothermal explosions (to name just a few). Prehistoric mines and quarries are also sometimes mistaken for impact craters.
Although the USGS has been involved in impact crater research, we are neither the experts nor the ultimate authority on impact craters. Canada’s University of New Brunswick Planetary and Space Science Center is the best resource for confirming a structure as an impact crater. They maintain an Earth Impact Database and provide guidelines for identification of impact craters.
Learn more: This Dynamic Planet: World map of volcanoes, earthquakes, impact craters, and plate tectonics (2006)
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About 35 million years ago, a large comet or meteor slammed into the shallow shelf on the western margin of the Atlantic Ocean, creating the Chesapeake Bay impact crater. This report, the second in a series, refines the geologic framework of southeastern Virginia, south of the James River in and near the impact crater, and presents evidence for...
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USGS Astrogeology team members at Meteor Crater.
Chesapeake Bay Impact Crater
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Dome within Mount St. Helens' crater, Nov. 2005
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- Collection: Earth as Art 2
- Source: Landsat 7
- Download:
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Aerial view of Arizona's Meteor Crater, a 180 meter deep, 1.2 kilometer diameter bowl-shaped impact crater in Northern Arizona. The crater formed approximately 50,000 years ago by the impact of a 100,000-ton iron-nickel meteorite that was approximately 30 meters in diameter and struck at an approximate speed of 12-20 km/sec.
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