http://www.usgs.gov/newsroom/article.asp?ID=1919&from=rss_home

Illinois Earthquake is a Wake-Up Call
Released: 4/18/2008 2:07:11 PM

     Contact Information:
     U.S. Department of the Interior, U.S. Geological Survey
     Office of Communication
     119 National Center
     Reston, VA 20192

   

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Today's early morning earthquake that jolted many in the central U.S. is a reminder that seismic events do occur in areas not normally thought of as "earthquake country." It is also a lesson that earthquakes east of the Mississippi River are felt more widely than those in the west. This event was felt as far west as Kansas, as far north as Upper Michigan, and as far south as Georgia.

"Earthquakes of comparable size are felt over greater distances in the East than those occurring in the West," said Harley Benz, seismologist for the USGS. "Earthquakes in the central U.S. are infrequent, but not unexpected."

The preliminary magnitude 5.2 earthquake occurred at 4:37 am Central Daylight Time and was centered about 38 miles north-northwest of Evansville, IN or 128 miles east of St. Louis, MO. It occurred in an area known seismically as the Wabash Valley Seismic Zone. Today's event is the strongest earthquake in southern Illinois since November 1968, when a 5.4 earthquake occurred.

On Monday, April 21, the USGS will be issuing updated earthquake hazard assessment maps for the entire U.S. The information on these maps is used to update building codes.

Classified as "moderate," today's event caused some damage and was followed by aftershocks, the largest a M4.6 that occurred at 10:15 am Central Daylight Time. Of much greater concern, however, is the potential for the adjacent New Madrid seismic zone to generate severe earthquakes. During the winter of 1811-1812, a series of three very large earthquakes - the strongest earthquakes to strike the lower 48 states during historic times - devastated the area and were felt throughout most of the nation.
Occurring only a few weeks apart on Dec. 16, Jan. 13, and Feb. 7, they generated hundreds of aftershocks, some severely damaging by themselves, which continued for years.

Building codes used in the region incorporate a significant degree of risk from earthquakes, but many buildings constructed before these codes were in place or updated have not been adequately retrofitted.

USGS research into ground shaking is used by building officials to update building codes based on the most up-to-date information. As new buildings replace older, more dangerous structures, death tolls from earthquakes have been significantly reduced in the U.S.

More information on this event and the history of the region is found on: http://earthquake.usgs.gov/eqcenter/recenteqsus/Quakes/us2008qza6.php

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... Meteor shower tonight -- bring your own soap!!
___ Blue Wave/QWK v2.12

Jo Firey wrote:

The USGS calls it the Wabash Valley Seismic Zone.

Some people on the east coast felt it. <g>

... Conference on Global Warming cancelled due to blizzard.
___ Blue Wave/QWK v2.12

Gloria wrote:

DeeTee and my Mary -- about 15 miles apart in Ohio -- did not
feel it. (Read later that a shelf fell at DeeTee's in Ohio.)

... Were Jean-Luc Picard and Mister Clean separated at birth?  
___ Blue Wave/QWK v2.12

Nann asked:

Before I answer that I want to reveal an East coast data:

   1886, August 31   Charleston, SC      60 deaths   M6.6

Moving to the West coast:

We don't even feel a 5.2 so we can't talk about it.  <G>

That's not entirely true, as a 5.2 can knock things off the
shelf of a liquor store, or a curio shelf at home.  If ONE
bottle or ONE can drops off a shelf at a grocery store, it
becomes news for days and days -- unless the president dies.

BFD, if you know what I mean.

Some California history:

   1906, April 18-19 San Francisco      503 deaths   M8.3
      (With ensuing fires, death toll at least 700)

   1933, March 10    Long Beach         115 deaths   M6.2

   1971, Feb. 9      San Fernando        65 deaths   M6.6

   1989, Oct. 17     San Francisco       62 deaths   M7.1
                     (Loma Prieta)

   1992, June 28     S. California        1 death    M7.5

   1994, Jan. 17     Northridge          61 deaths   M6.8

   I felt that one in Jamul (East county).  The death toll
   would have been much higher if people had been at work
   and students in school.  Luckily it happened when most
   folks were still in bed.

   Dang, I can't locate data for the Paso Robles tremor
   in 2004.  Mary and I stayed overnight there, we ate
   breakfast there the next morning, then continued north
   on U.S. 101.  I had just walked into HQ of Soledad FD
   and noticed the apparatus swaying to and fro.  Then
   dispatch notified all stations to remove apparatus
   outside and check for structural damage. (That's SOP
   in California.  Emergency personnel can't respond to
   emergencies if their apparatus is crushed inside a
   collapsed firehouse.)

Each change in the Richter Scale represents a quake 10 times
stronger or weaker than the value above or below.  But while
searching, I discovered that nowadays the USGS does not use
the Richter Scale, but a "movement" scale.  Thus tremors are
now classified M 4.1 or M 5.6 or M 7.3 etc etc etc.

... Not tonight, dear...I have a newsgroup to read.      
___ Blue Wave/QWK v2.12

We're the ones receiving phone calls from Massachusetts, Florida,
South Carolina and Louisiana, asking if we are alive, safe and
sound -- after a quake in 'Frisco or Eureka.

Checking Caller ID on our return from spending Christmas 2004 in
San Jose, I discoverd that the phone rang off the hook after the
Paso Robles tremor, worrying dozens of our friends and relatives
back East because we were traveling (actually just north of Paso
Robles after leaving it 1 hour earlier) and not home to answer
the incoming calls.

... ASA:  A place where you are recognized as a friend!  
___ Blue Wave/QWK v2.12

Welllll, I still had $700 out of $2200 in my pocket. Ate, drank, saw a
couple of shows, and (of course) gambled. So I feel pretty good about the
experience! Will post a bit about the trip later. First try at golf this
morning!
GaryZ

Gary replied to Joe:

The absolute best show I've seen in Vegas was Tiny Tim.

The absolute worse show was Barbara Eden.

Be sure you clean your clubs and wash your balls first.

... Is a golf ball a sports malady like a tennis elbow?
___ Blue Wave/QWK v2.12

-=> Quoting SpamfreeRe: Shake, rattle & rollentex.ca to All <=-

Joe wrote to Gary:

And Joan warned:

Now what fun would life be if I behaved?

... I know it all. I just can't remember it simultaneously.
___ Blue Wave/QWK v2.12