A Major Quake in the Near Future?

Last night a 3.5 magnitude earthquake hit Alabama. The quake itself caused no damage and hardly anyone noticed it. But that�s not the real story, because this is the fifth earthquake Alabama has experienced in seven years and the third this year.[1]

April 29, 2003- A quake registering 4.9 on the Richter Scale was recorded near Fort Payne Alabama.[2]



October 17, 2003- An earthquake measuring 2.7 was recorded 26 miles northwest of Tuscaloosa.[2]



March 20, 2004- A tremor measuring 2.8 hit Helena Alabama.[2]



May 9, 2004- Another minor quake hit Helena Alabama. [3]

August 19, 2004- 3.5 quake hits Alabaster, AL



What is interesting is that these may seem like small quakes yet Alabama is not a very active state when it comes to Earthquakes. These small quakes may be a prelude to a big earthquake along the New Madrid Fault line.[4] If a large quake occurs along this fault line the damage would be extensive and damage 20 states.

THE HIGHEST EARTHQUAKE RISK in the UNITED STATES outside the West Coast is along the New Madrid Fault. Damaging tremors are not as frequent as in California, but when they occur, the destruction covers over more than 20 times the area because of underlying geology.

A DAMAGING EARTHQUAKE in this AREA, 6.0 or greater, occur about every 80 years (the last one in 1895). The results would cause serious damage to schools and masonry buildings from Memphis to St Louis.

A MAJOR EARTHQUAKE in this AREA, 7.5 or greater, happens every 200- 300 years (the last one in 1812). There is a 25% chance by 2040. A New Madrid Fault rupture this size would be felt throughout half the United States and damage 20 states or more. Missouri alone could anticipate losses of at least $6 billion from such an event.

THE GREAT NEW MADRID EARTHQUAKE OF 1811-1812 was actually a series of over 2000 shocks in five months, five of which were 8.0 or more in magnitude. Eighteen of these rang church bells on the Eastern seaboard. The very land itself was destroyed in the Missouri Bootheel, making it unfit even for farmers for many years. It was the largest burst of seismic energy east of the Rocky Mountains in the history of the United States and was several times larger than the San Francisco quake of 1905.

The quake of 1811 actually changed the course of the Mississippi River to give you a little idea of how strong this quake could be.



[1] www.wsfa.com...
[2] www.abc3340.com...
[3] www.abc3340.com...
[4] www.scchealth.org...


[edit on 20-8-2004 by BlackJackal]

Assuming your epicenters are where the stars are, in your maps, I would have to say this is not activity along the New Madrid Fault, but along the southern edge of the Appalachian range, which would be the continental divide between the plates. Perhaps this is an early indication of the region of the Appalachians becoming more active? Anyone know of any ancient volcanic activity along this range that could be stirring again? Of course, the New Madrid Fault formed when teh continent tried to tear itself apart, maybe this is a new shift in tectonic activity on the North American Plate itself?

Where's a geologist when you need one?

Originally posted by everlastingnoitall
Assuming your epicenters are where the stars are, in your maps, I would have to say this is not activity along the New Madrid Fault

Yeah,
New Madrid Fault is in different place.

Crosses indicate quakes after 1974.
quake.wr.usgs.gov...
The New Madrid Fault Zone (NMFZ): quake.ualr.edu...


In fact:
This map shows earthquakes of the New Madrid and Southern Appalachian seismic zones from 1974 through 1994.

SOUTHERN APPALACHIAN SEISMIC ZONE: www.gsa.state.al.us...

[edit on 21-8-2004 by E_T]

Another one occured on August 28, 2004 in Helena with a magnitude of 2.8

A micro earthquake occurred at 05:06:43 (UTC) on Saturday, August 28, 2004. The magnitude 2.8 event has been located in ALABAMA. (This event has been reviewed by a seismologist.)

earthquake.usgs.gov...

quakes happen, big deal, not worth a thread.

Also, you can always go rattling on and on about another ones coming, NO #, earthqaukes have always happened on this planet, and always will.

Originally posted by Murcielago
quakes happen, big deal, not worth a thread.

Also, you can always go rattling on and on about another ones coming, NO #, earthqaukes have always happened on this planet, and always will.

Yes, earthquakes happen but an earthquake in Alabama is anomaly. Earthquakes do not happen in Alabama very frequently so when they do it is news. What is of concern to me is the concentration of tremors in the Helena/ Alabaster city areas.

Originally posted by everlastingnoitall ... but along the southern edge of the Appalachian range, which would be the continental divide between the plates.

I wonder if it has anything to do with the angle change in the North American Plate? It appears to be sinking ever so slowly in the south and rising every so slowly in the north. It is believed that this is a normal action as the glaciers melt and the weight of the ice is reduced on the northern end of the tectonic plate.

Originally posted by everlastingnoitallPerhaps this is an early indication of the region of the Appalachians becoming more active? Anyone know of any ancient volcanic activity along this range that could be stirring again? Of course, the New Madrid Fault formed when teh continent tried to tear itself apart, maybe this is a new shift in tectonic activity on the North American Plate itself?

It may be due to displacement between the plates as their movement becomes more up/down than pushing together.

Earthquakes in alabama are not abnormal, every place on the planet will generally have an earthquake. Take the uk, its not near anything, sits atop the european plate and have earthquakes on a frequent basis.

I wish people would stop wetting their pants everytime their is an earthquake, if you suddenly get an 8 in alabama then maybe I'd be worried, but the magnitude of the quakes is normal for such a region.

Chuck Stevenson has got the right idea, glacial unloading its called and the earthquakes you are probably seeing are the result of the crust resetting itself.

Again I will repeat. Earthquakes are not common in Alabama.

neic.usgs.gov...

www.cnn.com...

"We have events like this about every 10 to 20 years. So far they have not been serious. There's potential for a larger event," Long said.

"It was felt widely. These earthquakes in this area are typically deeper focus. That is they're down 20 to 30 kilometers in the Earth's crust. So they're felt over a wide area but not as strongly as some other types of earthquakes."

Long said the building code isn't as strict in the Southeast as it is on the West Coast. He said there was not a statutory mandate to build to code until about 10 or 15 years ago, but that buildings constructed since then should be safe.

John Bellini, a U.S. Geological Survey geophysicist, said: "We would expect items knocked from the shelves, pictures knocked off the walls, people waking up. We wouldn't expect any casualties.

"In California, you get something like this once every month. In the East, it's relatively uncommon but not unheard of."

The largest earthquake in Alabama occurred north of Birmingham in October 1916. It registered a magnitude of 5.1. Georgia's largest earthquake was also in 1916, about 30 miles southeast of Atlanta. It registered a magnitude of 4.1.

Originally posted by BlackJackal
Again I will repeat. Earthquakes are not common in Alabama.

Consider this, the melting of the glaciers has increased exponentially over the last 20 years, therefore the Glacial unloading (weight) on one end of the North American Plate is getting less. Much like a balance, the north american plate is now seeking equalibrium, so in the north it will rise and in the south it will fall, which causes deep earthquakes along the places where the North American and Atlantic plates join.

Alright I emailed the USGS and asked this question.

> Greetings,
>
> I am interested in the recent earthquakes that are occuring in Alabama.
> There have been atleast 4 minor tremors since May 2004 and the most recent
> occuring August 28 2004.
>
> What do these quakes indicate? What Fault line are they occuring on?
> Could this be an indication that a large earthquake could occur in this
> area at some point within the next one to two years?
>
> Thank you in advance.

Let me be honest with you I was not expecting this responce at all. So read it for yourself and your decide.

We don�t exactly know why there are earthquakes in this area, nor do we know what to expect. Siesmology is still a young science, and there are still a lot of questions that remain unanswered.

-Lisa
--------------------------
Lisa Wald
USGS Earthquake Hazards Program
Golden, CO