A 7.1 level earthquake hit south-central Alaska early Sunday morning. It was strong and prolonged, and caused gas and fire to destroy four houses on the Kenai Peninsula southwest of Anchorage. No injuries have been reported.

Principally, the quake hit on the Cook Inlet's west side, with a depth of 76 miles. It was felt from Fairbanks to Juneau, according to Alaska Dispatch News.

Alaska is connected to the Earth's most active seismic area, the circum-Pacific seismic belt. That belt extends to the state and the long chain of the Aleutian Islands. 

Worldwide, more than 80 percent of tremors take place in the circum-Pacific belt. The area occupies a horseshoe shape in the Pacific Ocean basin, along the coasts of Asia and North America and as far south as just below Australia and the lower tip of South America. About six percent of large, shallow earthquakes are in Alaska or near it. There, as many as 4,000 earthquakes are detected at various depths in a year, according to the U.S. Geological Survey.

Most earthquakes in the state take place in the Aleutian Island Arc, extending about 2,500 miles for the course of the seismic area, and from Fairbanks through the Kenai Peninsula to the Near Islands, according to instrument locations of movement since around 1900. The Near Islands are the Aleutian Islands' western-most isles. 

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