Among the different things I've collected over the years are Quake simulation and projection maps. Particularly ones for the Midwestern United
States, since I happen to live here. I happen to be looking at some of them for another reason tonight and got to really thinking about this one.
I didn't produce the graphic (I'd picked it up from a State site during a college project) and a correction is important. The Midwest Quake was
not 6 but 6.8.
1994 was, of course, the Northridge quake.
Many people have heard quite a bit about the new Madrid Quake series of 1811/1812. However, the second one on the map above is the 1895 Halloween
Quake which was centered in Charleston, Missouri. It was quite a shaker, to say the least. It's surprising that more mention isn't made of it, given
how widely felt it was.
There is more, but first I have a more technical look at what the two quakes felt like.
Northridge - 1994 (USGS)
Charleston, Missouri - 1895 (Halloween Quake) (USGS)
The scales at the bottom of the shakemaps are known as the Modified Mercalli Intensity
For those unfamiliar with it, the following chart comes courtesy of the
Missouri Department of Natural Resources
. I've made a thumb of it
because it's a large graphic showing a lot of information. In a nutshell though, it shows the relation between traditional Richter Scale readings and
the Modified Mercalli Intensity Scale. The Intensity Scale is a more accurate depiction of the impact and felt effects of the quake as opposed to
measuring straight energy released during the event.
Northridge, as many of us know, was a local / regional event. It also claimed 72 lives and over 9,000 injuries so it's not in human impact I compare
the two. The Halloween Quake did not have the same loss of life associated with it. Population density across time periods has a great deal to do with
that as well, in my opinion.
To quote Cal-Tech on the nature of the Northridge quake,
The earthquake caused very large ground motions with peak accelerations of 0.5 to 1.0 g in the Northridge area, decreasing to 0.1 g at distances
of about 50 kilometers (31 miles). (A "g" of acceleration is equivalent to the acceleration of gravity. There were a few sites near the Northridge
earthquake that recorded over 1 g of vertical acceleration. These ground movements would have been capable of throwing objects of any size into the
The pattern of damage and strong ground shaking was irregular, with severe damage in places like Sherman Oaks and Santa Monica. These effects were
caused by the complexity of the earthquake source and the wave propagation through complicated
USGS had this to say about the 1895 Quake.
This is the largest earthquake to occur in the central Mississippi River valley since the 1811-1812 series in the area of New Madrid, Missouri.
Structural damage and liquefaction phenomena were reported along a line from Bertrand, Missouri, in the west to Cairo, Illinois, in the east. Many
sand blows were observed in an area southwest of Charleston, Missouri, and south of Bertrand, Missouri. Isolated occurrences of sand blows also were
reported north and south of Charleston.
The most severe damage occurred in Charleston, Puxico, and Taylor, Missouri; Alton, and Cairo, Illinois; Princeton, Indiana; and Paducah, Kentucky.
The earthquake caused extensive damage (including downed chimneys, cracked walls, shattered windows, and broken plaster) to school buildings,
churches, private houses, and to almost all the buildings in the commercial section of
I have to say though. None of this is what really got my attention the most for thinking this all might be something worth sharing with everyone.
These quotes from an Illinois State Geological Survey Fact Sheet and are what really grabbed my attention. These are about the 1895 quake. Recall,
just a 6.8. These days, that wouldn't sound like that much in global context. Larger are certainly not uncommon.
Reports from other cities:
Memphis, Tennessee, suffered no damage, except that two chimneys in the suburbs were shaken down.
In Pittsburgh, Pennsylvania, a slight earthquake shock was felt in the suburbs of Bellevue and McKeesport.
Every building in Indianapolis was shaken. Thousands of people were awakened.
The earthquake rattled windows in Kansas City, Missouri.
Electric lights flickered at the Union depot. Chimneys were damaged and plaster walls cracked in Grayville and Albion, Illinois; Princeton, Indiana;
and Paducah, Kentucky.
(spacing added for clarity)
This same report has another happy statistic to share with the world.
1995 and beyond
Scientists calculate that moderately strong earthquakes, such as the Halloween 1895 quake, occur in the Central US every 70 to 90 years. There has not
been one of this magnitude since 1895. Arch Johnston, director ,of the Center for Earthquake Research and Information in Memphis calculated the
likelihood of a magnitude 6.3 quake or greater occurring within the next 50 years to be between 86 % and 94 %.
Geological Survey - 1995
I'm sure someone will correct me on this but that is saying about as close to 'It's going to happen' as science comes short of that "Certain"
word...they just never ever use. (Good ones, anyway). That's a thought to consider.
This is ATS and all. What kind of Doom Porn writer would I be to leave everyone pondering only one disaster?
I mean really. I know, demanding readers want more in this day and age. Well, ask and ye shall sometimes receive.
If it came at another 6.8 and nothing larger, I suppose this isn't a concern. If one looks, there is a hole across the country where no reactors sit.
If one looks at the top damage estimate map from 1895 or the map located in the Illinois State Survey sheet, it may be noted the shape of damage and
the hole where no reactors go, kinda line up. Almost conspicuously so. Almost as if they meant to do that.
Of course if it did come like the 1811/1812 winter series where there was a 7.7, 7.5 and 7.7 respectively (some first put them closer to 8.1),
I do hope the nation comes around to help us in fly-over country and Memphis will need the most, would be my guess. I try not to think about the
Nuclear Plant map overlaid to that one. It's one of those 'Ignorance is bliss' moments if there ever was one. I'm also thinking bridge builders
will be extremely busy for awhile, among countless others.
Quite a difference between California Quakes and the Midwest, eh? Geology is everything, I'd say.