While the frequency and severity of earthquakes in Michigan don't merit safety drills, the state has felt tremors from time to time. That being said, the state ranks 36th in the nation for earthquake hazard, and no earthquake-related deaths have been reported.
Low Earthquake Hazard Risk
Most of Michigan, along with much of the northern Midwest, is in the lowest hazard category (of seven) for earthquakes. There is, however, a strip of land along the southern border of Michigan's Lower Peninsula that includes Detroit and poses some threat in regard to ground shaking.
In addition to experiencing shake from several earthquakes originating outside of the state, the strip contained the epicenter of the South-Central Michigan earthquake of 1947 – the largest earthquake to originate within the state according to the U.S. Geological Survey website. The epicenter of the 1947 earthquake was located just southeast of Kalamazoo, where it was felt as an intensity VI. Damage was reported as far away as Cleveland, Ohio; Cadillac, Michigan, Chicago, Illinois; and Muncie, Indiana.
Earthquakes East of the Rockies
The area east of the Rocky Mountains is different geologically from the area west. First of all, the bedrock that runs through the Central and Eastern U.S. is ancient and relatively rigid, allowing seismic waves to travel farther without losing intensity. In other words, an earthquake in the Central or Eastern U.S. can be felt in an area up to 10 times larger than a comparable magnitude earthquake in the west.
In the fault-riddled west, earthquakes are the result of crustal plates rubbing up against one another. The earthquake hazard in the Central and Eastern U.S. on the other hand is the result of weak sports in the middle of the continental plate. In other words, ancient tectonic forces created underground rifts that started to form but stopped before they separated the crust. The resulting rifts or series of faults can be buried as far as five miles under layers of soil, sand, and/or clay. Because the faults are not visible, scientists plot past earthquake activity to determine where weak spots might be located.
Closest Hazard Zone in the U.S. to Michigan
The most hazardous earthquake zones east of the Rockies are located approximately 350 to 600 miles from Michigan in the Mississippi and Ohio Rivers region. They include the Lower Wabash Valley series of faults by Terra-Haute, Indiana and the New Madrid Seismic Zone, a series of faults located deep beneath the surface of the earth in Missouri, Illinois, Arkansas, Kentucky and Tennessee. Otherwise known as the Reelfoot Rift, the network of faults in the New Madrid Seismic Zone is estimated to be 40 miles wide, 300 miles long and the point of origin of over 200 small earthquakes each year – most of which can't be felt.
New Madrid Seismic Zone
The New Madrid Seismic Zone has historically given the scientific community cause for concern, mainly because it was the point of origin for the biggest earthquake to affect the Central and Eastern United States in recorded history. Back in 1811 and 1812, three major earthquakes, registering from 7.5 to 7.7 on the Seismic magnitude scale, rocked most of the Eastern U.S. Historically, the earthquakes are ranked as the 5th to 7th largest to have ever rumbled the 48 states. The series of earthquakes was the biggest east of the Rocky Mountains and was felt in Detroit as a V on the Mercalli Earthquake Intensity Scale, a measure of Seismic intensity.
Closest Hazard Zone in Canada to Michigan
Some of the most hazardous seismic regions near Michigan are in Eastern Canada: Charlevoix-Kamouraska in Quebec and along the St. Lawrence River from Ottawa to Quebec. There have also been earthquakes in Timiskaming and Kipawa, some of which were felt in Detroit, Mt. Clemens and Port Huron as an intensity V.
Sources and More Information
- Largest Earthquakes by State / U.S. Geological Survey
- New Madrid 1811-12 Earthquakes / U.S. Geological Survey
- Significant Earthquakes and Seismic Hazard / Natural Resources Canada
- U.S. Earthquake Hazard Map / U.S. Geological Survey
- Earthquakes in the Midwest / Nova / PBS.org
- Putting Down Roots in Earthquake Country / Your Handbook for the Central U.S. / U.S. Geological Survey
