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
Great Lakes of the continent raise concerns. Under the U.S. "Water Resources Development Act", diversion of water from the Great Lakes Basin requires the approval of all eight Great Lakes governors through the Great Lakes Commission, which rarely occurs. International treaties regulate large diversions. In 1998, the Canadian company Nova Group won approval from the Province of Ontario to withdraw of Lake Superior water annually to ship by tanker to Asian countries. Public outcry forced the company to abandon the plan before it began. Since that time, the eight Great Lakes Governors and the Premiers of Ontario and Quebec have negotiated the