Keweenaw Fault

[1] The fault thrusts lava flows of the Midcontinent Rift System onto sedimentary rocks of the Jacobsville Sandstone.

The fault is part of the inversion of the Midcontinent Rift where a region that had previously undergone extension experienced significant contraction.

[2] The Keweenaw Peninsula, itself, is the southeastern side of a large syncline beneath Lake Superior.

[3] The fault is more than 100 miles (160 kilometers) long and extends from the tip of the Keweenaw Peninsula in the northeast to a termination near the Michigan-Wisconsin border in the southeast.

[5] A seismic event in 1906 claimed to be an earthquake has been attributed to a rock burst, as the area has been significantly mined.