On Oct. 4, 2010, a crack extending some 360 feet (110 meters) long and 5 feet (1.7 m) deep opened up in the forest near Birch Creek on Michigan's Upper Peninsula, just north of Menominee. The gaping zigzag was accompanied by a deep booming sound. Here's a look at the odd crack and resulting upheaval in the forest. [Read the full story on the Menominee crack]
The location of the event
The upheavel of earth led to a deep booming sound that rang out through the forest near Birch Creek, shaking nearby homes wiht the strength of a magnitude-1 earthquake, researchers found. The next day, residents found the gaping crack (marked on this Google Earth image). (Credit: Michigan Tech College of Engineering)
Nature's strength
The crack separated trees from their roots, and in some cases split small tree trunks. (Credit: Michigan Tech College of Engineering)
Powerful forces at work
A view of roots split by the Menominee crack, which spanned 360 feet (110 meters) long and about 5 feet (1.7 m) deep; it sat atop a ridge that was nearly 7 feet (2 m) high and about 30 feet (9 m) wide at its largest point. (Credit: Michigan Tech College of Engineering)
Pushed away
Trees tilted away from the crack by about 13 degrees, with trees farther from the crack tilting at smaller angles. (Credit: Michigan Tech College of Engineering)
Significant damage
A close-up of the crack, which is about 2 feet wide (0.6 meters). Scientists have found that during this event, bedrock limestone violently heaved upward to displace the overlying clay layer. The surface of the clay layer stretched as it bent upward, resulting in the giant crack. (Credit: Michigan Tech College of Engineering)
Evidence of the event
The trees tip in a way that is perpendicular to the surface of the ridge, confirming that the ridge is a new feature. (Credit: Michigan Tech College of Engineering)
Double tree
A double tree, with two trunks growing from one root ball, had fallen and was removed before the crack appeared. (Credit: Michigan Tech College of Engineering)
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