One of the things to keep in mind is that it has always been the standard operating procedure of the USGS to downgrade the size of the New Madrid
quakes in order to prevent panic from the public.
The February 7, 1812 quake is usually said to have been around 8.0 and even many sources claim as low as 7.4. 7.7 is a typical average of the
published estimates. What you have to understand is that most of that is done on purpose as to not to greatly alarm the public of the threat.
Any seismologist that has studied the New Madrid system and that previous quake knows that the actual magnitude is far higher than that. That quake
was at least an 8.9 at the very minimum. They were in reality and truth more powerful than anything man has witnessed since the Richter Scale was
invented, due to the amount of distance the waves traveled. That means stronger than the 1960 9.5 Chilean quake.
You have to remember that since the Richter Scale did not exist back then, the USGS and other government and "official" government-related sources
like colleges can just make up whatever numbers they want. But by the Mercalli Scale, those 1811-12 quakes are the worst ones in recorded human
history, and not even the biggest ones that have hit the New Madrid fault system. Also keep in mind that for example in California you generally get a
jolt earthquake. Which means up and down. These are very scary and loud, something like hitting a pot hole. However, the ground movement is not as
extreme as a rolling earthquake that starts to slide out of control.
If you get big quakes in New Madrid, the ground literally rolls back and forth (like shaking a tree branch), as much as 30 feet near the epicenter.
The ground cannot recover and very quickly begins to liquefy. But even as far away as Indiana the ground movement was estimated to be up to 10 feet.
That's like a 9.0 mega thrust earthquake effect being felt.
And as has already been pointed out these quakes are very shallow and there is no geography to stop their waves as they spread out across the eastern
US. That February 1812 quake, which was really at LEAST 8.9, was many magnitudes more devastating and destructive than the recent 8.8 Chilean quake.
Again, no big mountain ranges nearby to absorb the waves and the ground layer around New Madrid is basically sandy, watered down and mud in a lot of
places. Remember this is the Mississippi River area. So the ground contains large amounts of water and sand. Combine that with no big mountain ranges
to absorb the waves and you get catastrophic effects. And yes, the estimated magnitude of 7.7 for a possible future "big New Madrid quake" is very
The 1812 New Madrid quake did more damage to the geography than the 1964 Alaskan quake, which was a 9.2
And the thing to really remember is that the difference between an 8.0 or a 9.5-10 is the distance of the quake and the duration of the quake, and
that then allows for the release of energy amount to increase on the Richter Scale. It seems most people don't understand that. It does not mean that
the 9.5 quake is necessarily worse than say an 8.0. It just means that more energy was released, because it hit a bigger area.
If you have a particularly violent rolling quake in weak ground, which is exactly what happens at New Madrid, with no big mountain ranges around to
absorb the shock....................
What you get is essentially total destruction that might as well be unlike any other quake known to man since the Richter Scale was invented. The 1812
quake "didn't severely damage areas not around the epicenter" because there was no infrastructure back then. However, rail lines that were outside of
the epicenter area were greatly bent, as much as 6-12 feet in Illinois. In today's terms, that means the high on Mercalli Scale in heavily populated
areas. That means destruction on land never seen in any earthquake since the Richter Scale was invented, even outside the epicenter area.
The USGS and other official sources have never told the public what the true danger is. The thing that makes it even worse is that in places like
Saint Louis and Memphis there really are not buildings that are built to withstand a quake. It would be much like when you see those big quakes hit in
places like Haiti, Iran, China, Turkey.
Cities like Saint Louis and Memphis would be almost annihilated and Saint Louis is well beyond the epicenter region. The death toll that FEMA gives
for such an event (86,000 estimated) is ridiculously low and the real death toll would dwarf that. We are talking about Saint Louis and Memphis each
alone being like Haiti was. Not to mention all the deaths from flooding from the Mississippi River, from all the blown gas lines (there are huge gas
lines in the area), from the nuclear reactors in the area that might be compromised, and the starvation and dehydration deaths that would follow. Even
many people freezing to death if it happened in the winter, like it did in 1811-12.
The US economy would be destroyed because the Mississippi River commerce would shut down. The estimates that these official sources like government
funded studies, colleges, and the USGS put out are an extremely sugar coated white washing of the true danger. During the 1811-12 earthquakes, people
that lived in Indiana described 2-3 days of darkness after the quakes because there was so much debris ejected into the atmosphere.
Just imagine Indiana today being dark for 2-3 days with no sunlight during the middle of winter. Just imagine all the power and transportation being
down for months on end, etc. All the disease spreading. The death toll and destruction would be almost incomprehensible if it happened in modern
times, and these government estimates are basically just fabricated out of thin air, so as to not alarm the public too much. It would be like a much
worse Haiti event, only it would also negatively effect the world economy.
It is accepted that the 2-7-1812 New Madrid quake was more destructive to the geography than the 9.2 1964 Alaskan earthquake. They just don't want to
let the public know the real hazards.
To give you an idea, if "The Big One" were to hit San Francisco or Los Angeles, and "The Big One" for either area is estimated to be between 7.8 to
possibly 8.3 (although that big is unlikely).......... Even if an 8.1 hit, which is a common estimate of a big San Andreas quake (8.0-8.1), the
effects could be felt as strong shaking over an area of about 50,000 square miles.
On the other hand, if a big New Madrid quake hits, the effects could be felt as strong shaking over an area of 1-2 million square miles, and 2 million
in the case of a huge quake like the last 1812 quake. A 7.0-7.2 New Madrid quake can cause strong shaking intensity over 1 million square miles, but
an 8.1 San Andreas quake can only cause it over about 50,000 square miles. Strong shaking does not refer to something minor, but rather something
around 6.0 in magnitude.
In many places in the eastern US, buildings cannot withstand 6 or more shaking intensity. And we are talking about 2 million square miles of land that
could feel that. And again, in the past New Madrid earthquakes of 1450 A.D and 900 A.D., the earthquakes were even bigger than the 1811-1812 New
Madrid quakes were, especially the 900 A.D. event, which was much stronger.
Try to imagine up to 6.0 shaking up to 2 million square miles out from the Mississippi River region, to both the east and the north directions from
edit on 4-2-2011 by Red Cloak because: (no reason given)