From the Survival Blog
Dear Editor,
I am a Geologist. I wanted to give
the short answer as to why the New Madrid Fault complex is dangerous. And this
IS the short answer.
1.
It is Still Active and always will be. Central-Cratonic faults
never completely de-stresses.
2.
New Madrid quakes Destroyed the Pre-Colombian Mississippi Mound
Builder Civilization.
3.
New Madrid quakes Destroyed the region in 1811-2 with
aftershocks all the way through the Civil War.
4.
The New Madrid Fault Complex is around 9 different faultlines
connected together, each capable of 7.5+ quakes. A quake on one shifts the
stress to trigger a quake on another. They don't all happen at once.
5.
Quakes are felt on the entire continent sharing what's called
the Cratonic Shield, which is basically continental shield rock that runs from
the Rockies to the Atlantic down to Florida and Mexico, and all the way to the
Arctic Ocean. So most of the USA's Midwest, East, South and Canada. The South
and Midwest will feel it most, but that whole shield will feel it.
6.
During the 1811-12 quakes church steeples swayed so much that
their bells rang... in Boston. The whole East and middle of the country will
feel these quakes, except the West which is isolated by very different geology
and many intervening faultlines.
7.
Last time the ground reshaped so severely that it changed the
course of the Mississippi River, making it flow backwards before it found its
way around the new high ground.
8.
Shaking caused liquefaction along several hundred miles of the
River.
9.
Sand geysers erupted 150 feet into the air, complete with coal
and natural gas that caught fire. Sulfur dioxide gas (more poisonous than
Cyanide) was also described in journals by survivors.
10. Entire log cabins
flipped over, sank into the ground, or both. In modern times, most levees,
bridges, roads build across water saturated ground, and probably earthen dams
are doomed in quakes over 7.5 magnitude.
11. Shaking was
described as over 3 minutes.
12. Where you are
affects what the shaking does. On hard rock you'll feel it badly, however your
house won't sink into the ground. This is greatly complicated by things called
Nodes, as you find with sound waves. This is why some buildings collapse and
others near them are largely undamaged.
13. What your home is
built from matters. Unreinforced masonry (brick) fares BADLY in an earthquake.
Stick lumber with foundation anchor bolts has the best survival in a quake, as shown
in Western homes.
14. In the Loma Prieta
(Bay Area 1989) quake, many people with private wells saw them cut off due to
ground shifting and had to be redrilled and recased and a new pump installed.
Factor that cost in.
15. Ground waves from
that LP quake also destroyed underground water and sewer lines and the state
funded and quietly taxed for the replacement which took 10 years. During that
time millions were exposed to contaminated drinking water full of cholera since
sewer and water lines are often close to each other under the streets. Those $$
billions are still being paid off as municipal bonds.
16. The cost of
repairing utilities and roads destroyed by multiple 7.5+ quakes affecting the
Entire East Coast, South, and Midwest is $$ trillions. They will have to be
done several times due to major aftershocks years later breaking them again.
The repairs cost more than the country can pay. Giving up public utilities is a
major step down in civilization and will lead to disease outbreaks.
17. Unchecked flooding
from ruptured levees and dams allows for many more mosquitoes, and malaria
should be expected to make a comeback, along with cholera and typhoid fever and
new infections like Dengue.
That's the short version. For some
idea of what severe ground shaking can do, see the Anchorage 1964 quake. Sincerely, - I.K.
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