While editing and searching for stories to post today on my website’s Geology News page, I happened to come across two stories about activity along the “New Madrid” fault zone in the Mississippi river basin area. And this inspired me to blog today about a not very well known (by the general public) major earthquake zone in the very heart of the Mid-Western United States.
When people think of a major earthquake happening in the United States, usually the first thought is about the predicted “Big One” to someday hit California. But very few people are aware that one of the most powerful earthquakes to hit America happened in the Mississippi river valley region just less than 200 years ago. These were quakes more powerfull than anything yet recorded along the infamous San Andreas fault.
It was December 16, 1811, and terrified residents of New Madrid, Missouri were awakened by violent shaking and a deafening roar as the first of three magnitude 8 quakes struck the heartland of the United States. Thousands of aftershocks also rocked the region that winter. Survivor’s eyewitness accounts reported large cracks opening in the earth, the visible rolling of ground waves, and the displacement of large areas of land sinking or rising. In one place the course of the Mississippi river was changed. And damage was reported as far away as Charleston, South Carolina, and Washington, D.C.
The bad news is that the potential is still there for future quakes of similar magnitude. And, with the greatly higher population density in that area today, a quake of such magnitude could kill hundreds of thousands people.
Here are three links I have selected that will give you good background information on the history of this particular seismic area’s history and potential:
http://quake.wr.usgs.gov/prepare/factsheets/NewMadrid/
http://www.eas.slu.edu/Earthquake_Center/eqhist.html
http://hsv.com/genlintr/newmadrd/
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