It all depends on where the quake hits.
If it hits the California region, most of the damage and shakes will be localized to a few hundred square miles.
If it hits along the New Madrid Fault or the Wabash Fault zone in the Midwest (along the Mississippi River, between Missouri and Tennessee Kentucky
for New Madrid Fault and between Southern Illinois and Indiana and northern Kentucky for the Wabash Fault), well, it will be a VERY bad day for us
Midwesterners.
For one thing, the whole area consists of dense rigid bedrock topped with sediments and sedimentary rocks, which can magnify the shakes as well as
carry the shaking for hundreds of miles away without diminishing too much in intensity. When the New Madrid had its last powerful quake (mag. 8) in
1811-1812 the quake actually rang the church bells in Boston, Mass., 1,000 miles away! This little map shows the area that was affected during a
"smaller" quake in 1895:
Believe me, a quake anywhere around here will make San Francisco's quake look like a mouse fart.
In 2008 we had a 5.4 Mag. quake on the Wabash fault zone. It was felt as far north as UP Michigan, as far west as Nebraska, as far east as West
Virginia, and as far south as Atlanta
I recall a few years ago, in 2004 we had a smaller quake in LaSalle County, which is west of Chicago about 80 miles. It was a 4.2 Mag. Being in
Chicago, I felt it like a large heavy truck driving by my house, but lasting for about 5-8 seconds and actually knocking over some stuff on my desk
and actually banging my bookshelf agianst the wall. That got my attention. Mind you this was a 4.2, what they call a no-biggie in California. Well
they sure felt it all over the place.
You can read up more about it on the USGS sites, as well as Wikipedia!
quake.wr.usgs.gov...
news.aol.com...
en.wikipedia.org...
All in all, it would make for a very interesting catastrophie that will dwarf Cali's "Big One".