As a former geology major, I am reading with interest. The Richter Scale is a logrithmic scale so every number is 10 times worse than the former. 3.7 is definitely a minor one...not to say that a bigger one can't follow.

The worst earthquake in U.S. history was in MO and IL in the 1800s. It was along the New Madrid fault line. It made the Mississippi change course and flow backwards.

There are fault lines just about everywhere, but, most are small. I have seen the fault in MI as well...in fact, we had to map it!