The October 2010 Menominee crack mystery may be resolved according to researchers with the Michigan Technological University. The large crack that appeared overnight wasn’t the result of any known process.
Residents in the area of Menominee, Michigan, reported a loud noise and the resulting large crack in the ground. Michigan isn’t a seismic area. The Menominee crack was initially thought to have appeared as a result of the first earthquake ever recorded in the Upper Peninsula. However, the seismic event registered under the 1 magnitude.
The riddle kept puzzling the scientific community. This surprising geological event remained a mystery until researchers with the Michigan Technological University took it upon themselves to gain deeper insight on the causes of the Menominee crack. According to their findings, the large crack is in fact what is termed a ‘pop-up’.
A pop-up typically occurs where glaciers or quarries recently receded. The Menominee area holds neither of these features. Nonetheless, the attributes of the Menominee crack are eerily similar to pop-ups occurring at the base of quarries or glaciers.
Wayne Pennington, lead researcher and dean of the College of Engineering at the Michigan Technological University stated that the Menominee crack is a unique feature. Pop-up structures were never observed outside the specific areas where they occur. Thus, the large crack of Menominee, Michigan was an exciting new object of study. According to Pennington,
“As far as we can tell, this is a one-of-a-kind event. But in case it is not, we wanted information about it to be available for other investigators”.
The research team headed to the site where they conducted seismic refraction tests. This type of tests can verify the features of a pop-up structure. Sound waves indicate that the crack occurred in region where the brittle limestone underneath fractured. One characteristic of a pop-up structure is that the underlying layers are bowed upwards.
The ridge of the pop-up structure suggests that the depth is larger than previously thought. Pop-up structures are created as the pressure is lessened when ice of rock layers have been removed in the case of glaciers of quarries.
While there are no quarries around and the glaciers disappeared more than 11,000 years ago, the Menominee crack presents all the features of a pop-up structure. The October 2010 Menominee crack mystery may be resolved. However, more research could indicate how a pop-up could occur in such an unusual spot.
Photo Credits: geo.mtu.edu