Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
Okay, let's clear up this argument now! According to the USGS (a much better source than Wikipedia, LOL), the river merely appeared to be running "backwards" - in other words, it was an illusion that was probably mistaken as fact after 200 years of storytelling.
"Large waves (seiches) were generated on the Mississippi River by seismically-induced ground motions deforming the riverbed. Local uplifts of the ground and water waves moving upstream gave the illusion that the river was flowing upstream. Ponds of water also were agitated noticeably."
I think it is reasonable to assume that rivers could have changed course temporarily during the quake if it was large enough, but once the quake was over (a matter of only a few minutes at most) there would be no reason for the rivers to flow any differently than they had prior to the quake.
Depending upon the magnitude of the quake, waters in lakes and ponds could have been displaced or agitated over 1,000 miles away, but it would have to be a big quake.
For example: Long-Period Effects of the Denali Earthquake on Water Bodies in the Puget Lowland: Observations and Modeling (http://www-bcf.usc.edu/~barberop/519.pdf - broken link)
The distance from the epicenter of the 2002 quake in Alaska to Seattle is 1,541 miles.
It is the 200th anniversary of the Great New Madrid Earthquake in SE Missouri.
Why no fearmongering, or even knowledge of the New Madrid fault?
New Madrid quake disaster was exactly 200 years ago - KansasCity.com (http://www.kansascity.com/2012/02/06/3414091/new-madrid-quake-disaster-was.html - broken link)
Why should there be fearmongering? Why does the OP assume lack of fearmongering equates to a lack of knowledge?
A bit ironic that the OP posted this about 2 hrs. 17 min. following a 4.0 quake on the New Madride near New Prairie Missouri.
Folks who live in this part of the US know that it is a matter of "when" the big one hits the New Madrid faultline again, not if. Practically speaking there is no reason to fearmonger about a statistical certainty of which most are knowledgable.
That 6.0 quake in Virginia had people crapping themselves as far away as NYC. A big quake would have people going crazy all up and down the Mississippi as far away as Chicago and New Orleans. Interesting coincidence that the New madrid Fault had a little earthquake today. I'd say that proves people were thinking about it.
That 6.0 quake in Virginia had people crapping themselves as far away as NYC. A big quake would have people going crazy all up and down the Mississippi as far away as Chicago and New Orleans. Interesting coincidence that the New madrid Fault had a little earthquake today. I'd say that proves people were thinking about it.
Anything above magnitude 5.0 is a concern. A 6.0 magnitude quake is serious enough to cause wide-spread damage and possibly injury in high density areas. That was a very serious quake in Virginia.
We average over 1,000 quakes per month in Alaska. At least one will be 4.0 or bigger per week, one will be 5.0 or bigger per month, and one will be 6.0 or bigger per year. Quakes 7.0 and bigger are too unpredictable, but generally speaking years or decades could go by before a really large quake hits.
Fortunately, the overwhelmingly vast majority of our quakes are where the 130+ active volcano and volcano fields are located, not around population centers.
Subduction zone quakes are a whole different animal than quakes in the center of a continent. The smaller, coastal plates many times behave as shock absorbers. Therefore, it is quite possible that a lower magnitude quake in the center of a continent can do more damage than a similar magnitude quake in a subduction zone because the shockwaves travel farther and with less impedance through a larger (continental) plate.
Also, I have to point out that this is the first time I've seen people behave snobbishly about earthquakes. It takes all kinds, I suppose!
They were most likely under 4.0 in magnitude. You just about have to be on top of the epicenter to feel quakes that small. Although, in areas not prepared for quakes a 4.0 quake can still cause damage. Particularly brick buildings that are not reinforced, which are all over the mid-west.
Exactly right.
During the 8.0 magnitude Paxson quake of 2002 the Trans-Alaska Pipeline was only a few miles from the epicenter. The 48" diameter pipe moved several feet, but did not break. It was designed to handle up to an 8.5 quake.
The mid-west does not get enough large quakes to warrant changes in building codes. Which means that when a large quake (6.0 or greater) does hit the area it will cause more damage than a similar magnitude quake on the west coast.
Oh but when it does happen, and buildings collapse, people will freak.
I think the biggest concern with the pipelines is that many of them go under bridges which cross the Mississippi, which are in dire straights already. This will also have the added problem of, how do you get there to help? If all of the bridges are down, and the local roads and interstates have been broken up, the area will be like New Orleans after Katrina, how do you get there to help? Airdrops only go so far, and this could be a large area.
You can feel a 4.0 there fairly well, its the ground type. There are no major rock formations to slow down the effects like there is in Cali and other areas. Thats part of the reason why the bells moved in Boston when the 8.4 hit in January 200 years ago.
Hell there was a guy 50 miles from town that set an old barn off with dynamite, and that shook the entire town once.
Still nothing to freak about, it will happen, and thats all it is to it. But the public outrage at the high death tolls in large cities will still change the building codes, most likely, who knows?
They were most likely under 4.0 in magnitude. You just about have to be on top of the epicenter to feel quakes that small. Although, in areas not prepared for quakes a 4.0 quake can still cause damage. Particularly brick buildings that are not reinforced, which are all over the mid-west.
Exactly right.
During the 8.0 magnitude Paxson quake of 2002 the Trans-Alaska Pipeline was only a few miles from the epicenter. The 48" diameter pipe moved several feet, but did not break. It was designed to handle up to an 8.5 quake.
The mid-west does not get enough large quakes to warrant changes in building codes. Which means that when a large quake (6.0 or greater) does hit the area it will cause more damage than a similar magnitude quake on the west coast.
There was exactly 1 brick building between Memphis and STL when the earthquakes struck.
As I posted upthread, it only lost it chimney, and the building is still there.
Oddly enough, all the homes constructed in the area with the French poteaux en terre method sustained little or no damage. Post in ground - Wikipedia, the free encyclopedia
The poteaux sur sole built houses sustained little damage, either.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
