Great Lakes tectonic zone southern Ontario. Several earthquakes have been documented in Minnesota in the last 120 years, with at least six in the GLTZ. The epicenters show a clear relationship to tectonic features of the state; four epicenters lie along the Great Lakes tectonic zone. Depths are estimated at . The best-documented event occurred on July 9, 1975, near Morris, Minnesota, with a magnitude of 4.6, and a felt area of covering parts of four states. Wisconsin has had no earthquakes along the GLTZ, Michigan's Upper Peninsula has had four earthquakes in the vicinity of the GLTZ – Negaunee, Newberry and two in
Naval Station Great Lakes opened. The policy of segregation led to small service school classes with only four or five students in a class. By 1944 Great Lakes began to integrate training and all training was integrated by mid-1945. The Golden Thirteen were commissioned in March 1944 after training at Great Lakes. Four million served on active duty in the Navy during World War II. Over one million sailors were trained at Great Lakes. In 1948, a boot camp for WAVES (female recruits) opened at Great Lakes, first graduating 5 October 1948. In 1951, female recruit training left Great Lakes for United States Naval