Savonoski Crater in Alaska has long been without a scientific explanation because evidence of its formation was destroyed. (Photo by NPS, photograph by Kaiti Critz)
Savonoski Crater is a circular depression in southwest Alaska that scientists have long struggled to explain due to a lack of geological data. However, there is a scientific explanation for this lack of data, which allows us to confidently say that the depression is neither supernatural nor alien.
According to a 1978 article published on the University of Alaska Fairbanks website, the crater is approximately 1,600 feet (500 meters) wide and 360 feet (110 meters) deep. It is partially filled with water from precipitation and melted snow.
From above, Savonoski Crater looks like it could have been caused by a meteorite impact. Impact craters are typically round and deep, so Savonoski fits that description — but geologists have yet to find evidence of a meteorite impact in the region.
Extensive studies in the 1960s and 1970s found no evidence of meteoritic material or any impact rocks inside the crater that could confirm its impact origin. Researchers also found no rock debris around the crater that would indicate the meteorite had scattered material far from its impact site.
Alternatively, the crater could be a volcanic maar, a depression formed when magma rises from deep within the earth's crust and reaches the water table. The intruding magma heats the water to boiling point, and the resulting steam creates enough pressure underground that it eventually causes an explosion.
Volcanic maars often leave wide craters that fill with groundwater. For example, the 330-foot-deep (100 m) Ukinrek Maar in eastern Alaska formed during a 10-day eruption in 1977 and has since partially filled with water, according to the U.S. Geological Survey.
View of the Ukinrek Maars in Alaska. The eastern maar (front) is typical of volcanic maars, being a deep, circular crater filled with water.
However, according to studies in the 1960s and 1970s, there are no known volcanic features in the immediate vicinity of Savonoski Crater, and no evidence of magma beneath the basin. Therefore, the possible volcanic origin of the crater remains unsolved.
Scientists are of the opinion that the Savonoski crater is either a meteorite crater or a volcanic maar,
Sourse: www.livescience.com
