SAN FRANCISCO (CBS SF) — A large earthquake measuring 7.5 magnitude struck Alaska on Monday, prompting a tsunami warning for South Alaska and the Alaska Peninsula.

The U.S. Geological Survey said the earthquake struck at 1:54 p.m. PT about 56 miles southeast of Sand Hill and 570 miles southwest of Anchorage. The quake was followed by at least five aftershocks with magnitudes of 5.8. 5.7, 5.2, 5.5 and 5.9, along with several other smaller aftershocks.

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The quake was originally measured at 7.4 magnitude before the USGS upgraded it to 7.5.

7.4 Alaska earthquake, October 19, 2020. (U.S. Geological Survey)

The tsunami warning was in effect for Pacific coasts from Kennedy Entrance, Alaska to Unimak Pass, Alaska. The National Tsunami Warning Center said the tsunami danger was still being evaluated for other U.S. and Canadian Pacific coast.

Just after 3 p.m. PT, the California Office of Emergency Services tweeted that there was no tsunami threat to California at this time.

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There was no immediate word of any damage or injuries.