[Rockhounds] New Madrid fault

[Alan Goldstein]

A recent article in Earth magazine indicated that the big quakes did not 
ring church bells in Boston. That is a perpetuated myth.

The eastern U.S. is much more uniform (less chopped up tectonically) than 
California. That is why a 5 magnitude earthquake in could wake up people in 
eastern KY and Ohio and why Charleston felt the New Madrid quakes. In 
California the numerous fault blocks dampen the vibration.

Alan


----- Original Message ----- 
From: "jb" <jabac at hal-pc.org>
To: "Dora Smith" <tiggernut24 at yahoo.com>; "Rockhounds at drizzle.com: A mailing 
list for rock and gem collectors" <rockhounds at lists.drizzle.com>
Sent: Tuesday, March 24, 2009 11:28 PM
Subject: Re: [Rockhounds] New Madrid fault


> Dora Smith wrote:
>> Dunno about that, but it would be interesting to see if it shakes up all 
>> that packed loose sand that apparently covers teh entire midwest and is 
>> what made the quake so destructive and caused it to spread all the way to 
>> Massachusetts.
>>
>> Yours,
>> Dora Smith
>> Austin, TX
>
> Glacial till is unconsolidated and thus subject to quickening if the right 
> energy wave is put through it. That is locally destructive, but could that 
> cause the quake to "spread all the way to Massachusetts"? Isn't it more 
> likely that the underlying sedimentary rock which covers all the Midwest, 
> which indeed is what makes up the Midwest, which came from the erosion of 
> the Appalachian  uplift, and which stretches all the way to New England, 
> was the transmitter? Could surface effects result in a seismic waves of 
> enough energy to be transmitted that far? Maybe so. But I suspect that 
> they would be swamped by the seismic swarm from a magnitude 8+ earthquake.
>
> john
>
> -- 
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