The correct answers are Alaska, California, Oregon, and Washington.
The states that are threatened by earthquakes are Alaska, California, Oregon, and Washington.
These states of the West Coast of the United States are threatened by earthquakes because they are located in a place known as the San Andreas fault. It is the sliding boundary between the Pacific Plate and the North American Plate. Everybody remember the San Francisco earthquake of 1906. This fault is what makes those U.S. states vulnerable to earthquakes. So states such as Alaska, California, Oregon, and Washington must be aware permanently and have actions plans against this natural risks.