[Rockhounds] Difference between East and West Coast US earthquakes, was New Madrid fault

[Carol J. Bova]

Dora,
It's not that scientists can't deal with dynamic complexity, it's that  
there is a major difference between California and the East Coast when  
it comes to earthquakes:

"East Coast earthquakes, such as the one that struck Charleston, South  
Carolina, in 1886 are felt over a much larger area than earthquakes  
occurring on the West Coast, because the eastern half of the country  
is mainly composed of older rock that has not been fractured and  
cracked by frequent earthquake activity in the recent geologic past.  
Rock that is highly fractured and crushed absorbs more seismic energy  
than rock that is less fractured. The Charleston earthquake, with an  
estimated magnitude of about 7.0, was felt as far away as Chicago,  
more than 1,300 km to the northwest, whereas the 7.1-magnitude Loma  
Prieta earthquakes was felt no farther than Los Angeles, about 500 km  
south. The most widely felt earthquakes ever to strike the United  
States were centered near the town of New Madrid, Missouri, in 1811  
and 1812. Three earthquakes, felt as far away as Washington D.C., were  
each estimated to be above 8.0 in magnitude. Most of us do not  
associate earthquakes with New York City, but beneath Manhattan is a  
network of intersecting faults, a few of which are capable of causing  
earthquakes. The most recent earthquake to strike New York City  
occurred in 1985 and measured 4.0 in magnitude, and a pair of  
earthquakes (magnitude 4.0 and 4.5) shook Reading, Pennsylvania, in  
January 1994 causing minor damage."
From: USGS, This Dynamic Earth,  Plate Tectonics and People
http://pubs.usgs.gov/gip/dynamic/tectonics.html

((Side note: I had just moved to Brooklyn in 1985, and the night  
before our furniture arrived, was sleeping on the floor in a sleeping  
bag when the quake on the Hudson Valley  fault hit. It felt like  
someone shaking me, and it wasn't until I sat up and realized my  
husband was still asleep, and another tremor shook us that I realized  
I was experiencing my first earthquake.))

Check out this database:
U.S. Geological Survey and New Mexico Bureau of Mines and Mineral  
Resources, 2006,
Quaternary fault and fold database for the United States, accessed Jan  
9, 2006, from USGS web site:
http//earthquake.usgs.gov/regional/qfaults/

It is so full of information and links and maps, you could spend a  
year in it!
Carol



On Mar 27, 2009, at 10:55 AM, Dora Smith wrote:

> Thanks!  Good article!  I will add it to my page.
>
> It looks like the scientists workign on the fault really can't deal  
> with dynamic complexity; it's a problem shared by alot of scientists.
>
> Rules that apply to the California faults don't apply to the New  
> Madrid fault system?   Come on!
> Yours,
> Dora Smith
> Austin, TX
> tiggernut24 at yahoo.com

> ----- Original Message ----- From: <betdav97 at aol.com>
> To: <rockhounds at lists.drizzle.com>
> Sent: Thursday, March 26, 2009 12:30 PM
> Subject: Re: [Rockhounds] New Madrid fault
>
>> Except for the first few posts, I have not been following this
>> thread, but this just came across the net, hope it hasn't been
>> posted already.
>>
>> http://news.aol.com/article/new-madrid-fault/398744
>>


--- StripMime Report -- processed MIME parts ---
multipart/alternative
  text/plain (text body -- kept)
  text/html
---