Has the US ever had an earthquake?
Yes, the US has had many earthquakes. Please see the related
link below for the largest ones on record.
The highest magnitude earthquake that ever occured in the US was the 1964 Alaska earthquake on Friday, March 27, 1964. According to the US geological survey, it had a moment magnitude of 9.2 and was the second largest earthquake recorded by seismometers. The most powerful earthquake being the May 22, 1960 Chilean earthquake with a magnitude of 9.5. Please see the related links for more information.