This date in science: Biggest North American earthquake since seismic data began to be collected.

March 27, 1964. On this date, at 5:36 p.m. local time, a 9.2 magnitude earthquake struck in the Prince William Sound region of Alaska, causing extensive initial damage and a subsequent tsunami.

Story:
http://earthsky.org/earth/this-date-in-science-biggest-earthquake-in-north-america