This past Thursday, an earthquake with a magnitude of 3.8 was registered near Bloomingdale, Indiana in Parke County. By most standards, it was a small quake, but many of us in the region felt it.
Our area is no stranger to earthquakes. Many of the quakes we feel are associated with the mysterious Wabash Valley Fault System. I say mysterious because so little is known about it. Most geologists believe the fault system runs generally from southeastern Illinois into southwest Indiana. It would be correct to think of the fault system as running beneath the Wabash River and extending for several miles outward west and east. The depth of this fault system is estimated to be about 4 miles below the surface of the Earth. Note that this is called a fault system. That means that, rather than one distinct fault line running underground, the Wabash Valley Fault System can be thought of as a series of ‘cracks’, much like the branches of a tree. At least, that’s what geologists believe. The fact is, nobody has ever actually seen this fault system.
While the most recent quake was a 3.8 on the Richter Scale, the Wabash Valley has experienced a few stronger earthquakes. In 1987 and 2008, earthquakes registering 5.2 were recorded. Historically, geologists believe this system has produced much larger quakes. Some may have been in the range of 6 to 7 on the Richter Scale. An earthquake of that magnitude today would be catastrophic.
So, while earthquakes in the Wabash Valley have been relatively minor over the past many years, there is always the possibility that one day, we’ll have the ‘big one’. Unfortunately, there is no way to predict when that might occur.
I often tell people that if they live in the Wabash Valley long enough, they’ll feel an earthquake. That’s because there’s a fault system right beneath our feet!