Avak crater facts for kids

Avak is a special kind of hole in the ground called an impact crater. It's located about 12 km (7.5 mi) southeast of Utqiagvik, Alaska, in the United States.

This crater is shaped like a circle, about 8 km (5.0 mi) wide and 1 km (0.62 mi) deep. Inside the crater, rocks that were changed by heat and pressure (called metamorphic rocks) and layers of sedimentary rocks are pushed up and bent out of shape. You can't see the Avak crater on the surface because it's hidden under a thin layer of frozen ground in a swampy area of the Arctic coastal plain.

Scientists believe the impact happened between 95 million and 3 million years ago. But clues from tiny plant fossils found in the material thrown out by the impact suggest it happened around 90 million years ago. The Avak structure also acts like a natural container underground, holding natural gas in nearby gas fields. These fields have collected about 37 billion cubic feet of natural gas in Jurassic sandstone layers.

Discovering the Avak Crater

The Avak crater was first found by the U.S. Navy between 1943 and 1953. They were using special surveys that look deep underground. In 1951–1952, the Navy drilled a well called Avak 1. They found rocks that were bent and broken from near the surface all the way down to 1,225 m (4,019 ft). They also found special patterns in the rocks called shatter cones, which are signs of a powerful impact.

Later, in 1995, geologists from the Geological Survey of Canada and the U.S. Geological Survey found more evidence. They discovered tiny features in the minerals called planar deformation features. These are also strong signs that the Avak structure was created by a meteorite hitting the Earth.