There are mysteries in southeast Missouri that have drawn state geologist David Hoffman here time and again. What makes this place different, sets it apart from the rest of the planet, is an upheaval that occurred eons ago, when the earth was younger and more rambunctious. The theory is that hundreds of millions of years in the past, the North American continent tried to rip itself apart here, creating a rift in the earth's crust. The resulting depression allowed the Gulf of Mexico to extend hundreds of miles northward into what is now southern Illinois. As the sea receded, the Mississippi and... More >>>
By Jennifer Silverberg
According to state geologist David Hoffman, "There's been two or probably three periods of movement in the last 10,000 years. That suggests a recurrence interval somewhere on the order of 3,000-5,000 years. The fact that these faults go up to the surface suggests moderate to large-scale earthquakes."