# How can a river change course?



## Osiris (Jan 18, 2005)

I came across an article, stating that an earthquake can change course. Now i also remember something about was it the Mississippi river? that flowed backwards for a couple days? How's something like that possible?


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## goodie (Sep 2, 2005)

Kinda hard to read, but hrer you go.
http://neic.usgs.gov/neis/eq_depot/usa/1811-1812.html


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## fish_doc (Jan 31, 2005)

Actually the mouth of the Mississippi river use to vary by miles but because of the building up of cities by man we now tell the rivers where they need to be. That is why there are so many problems when storms hit. The water cant "wander" where it thinks it needs to go anymore and it cant rise to the levels it needs to in order to flush silt out to sea.


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## TheOldSalt (Jan 28, 2005)

We had an earthquake here in south alabama just a few years ago, and while we actually have oodles of them every year, that one was unusual in that we actually noticed it and it tore up a few roads.
In fact, there are dozens of earthquakes all over the world every day, most of them being very small. The problem starts when there hasn't been any pressure release for awhile, so it's good to have hundreds of little ones.
The Mississippi River runs along the New Madrid fault, of course, and it's a doozy. Unlike the San Andreas of California, however, it is relatively very quiet. Cali has quakes every week if not every day, but they're usually lame on account of not having very much to have to do at a time. New Madrid is different, though, having a few major quakes instead of oodles of little ones.
The last time the New Madrid went off in a big way, the upwelling of the ground downstream of it did indeed make the mighty Mississippi suddenly find itself flowing uphill, which of course forced it to start flowing backwards. Lake Reelfoot was formed by the sudden backflow of water pouring into an area normally dry, and that lake remains today. A few days later the water was finally able to find a new route for going southward again, and I seem to recall that an aftershock helped put things right as well.

By the way, when that baby went off on that fateful day, it shook the whole continent, and I don't mean in some meager way that only seismologists with thier equipment could have noticed. The ground shook so much that the big church bells all the way in Boston, Mass were ringing from it!

I have to admit that I didn't read the stuff that Goodie linked to before making this post, and I'm sure it's more accurate than anything I just said. Goodie should know quite a bit about it, too, since he lives either in or very near New Madrid, the town sitting on top of the fault's main break. We actually have a nice number of FF'ers from that tiny little area, which is kinda cool.

Oh, by the way, rivers routinely change course from other things besides quakes. Water simply follows the path of least resistance, and when that resistance changes on account of varying factors, the flow changes to match. Oxbow lakes are formed by sharp bends in a river finally being pinched off when the main stream finds itself a shortcut, for example. Rivers also actively cut the land, too, effectively digging themselves a new path as they flow and receding behind themselves.


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## fish_doc (Jan 31, 2005)

You can see how many earthquakes there are on this site.
http://earthquake.usgs.gov/eqcenter/recenteqsus/

You will be suprised.


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## emc7 (Jul 23, 2005)

The new madrid quake destroyed the old Illinois capital of kaskaskia
http://www.prairieghosts.com/kaskaskia.html


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