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<TITLE>Recent NPR story: New Madrid Quakes: USGS Scientist Dispels Errant Report</TITLE>
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<FONT SIZE="2"><FONT FACE="Consolas, Courier New, Courier"><SPAN STYLE='font-size:10pt'>New Madrid Quakes: USGS Scientist Dispels Errant Report<BR>
NPR-WKMS<BR>
Jacque Day (2010-06-11)<BR>
<FONT COLOR="#0000FF"><U><a href="http://www.publicbroadcasting.net/wkms/news.newsmain/article/1/0/1662035/Local.Features/USGS.Scientist.New.Madrid.IS.the.Seismic.Zone.of.Origin">http://www.publicbroadcasting.net/wkms/news.newsmain/article/1/0/1662035/Local.Features/USGS.Scientist.New.Madrid.IS.the.Seismic.Zone.of.Origin</a><BR>
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NEW MADRID, MO. (wkms) - A little information, out of context, can be<BR>
dangerous. That's what we found out this week. A story suggesting that the<BR>
New Madrid earthquakes of 1811-12 originated in Southern Illinois gained<BR>
some traction in news outlets across the mid-continent. But as our<BR>
correspondent Jacque Day reports, that wasn't the whole story. Here, she<BR>
looks into the facts versus the fiction.<BR>
<BR>
The Wabash Seismic Zone was the source of the 2008 magnitude 5.2 quake in<BR>
this region.<BR>
<BR>
Dr. Susan Hough is a seismologist with the U.S. Geological Survey based in<BR>
Pasadena, California. She is the lead author in the paper, "Wagon Loads of<BR>
Sand Blows in White County, Illinois" published in 2005 in Seismological<BR>
Research Letters. She is also author of the new book Predicting the<BR>
Unpredictable: The Tumultuous Science of Earthquake Prediction.<BR>
<BR>
TRANSCRIPT<BR>
News outlets all through the mid-continent played the story. We even aired<BR>
it from our own station earlier this week. It went something like this:<BR>
"New research by the U.S. Geological Survey casts doubt on the long-held<BR>
idea that the New Madrid fault zone in Missouri's Bootheel unleashed a<BR>
series of devastating earthquakes in 1811 and 1812. The new study suggests<BR>
the culprit may have instead been the Wabash Valley Fault line that runs<BR>
through southern Illinois."<BR>
<BR>
It was a report that came down "from the wire," as we call it. And it<BR>
turned out to be grossly misleading. Granted, some of the stories proceeded<BR>
to hit on the facts, but the teaser did the damage.<BR>
<BR>
"The Devil is in the details."<BR>
<BR>
This is Dr. Susan Hough, a seismologist with the U.S. Geological Survey<BR>
based in Pasadena, California. To her surprise, her name popped up in some<BR>
of the aforementioned news reports. Hough is the lead author on a 2005<BR>
article in Seismological Research Letters. The article introduces evidence<BR>
that the smallest of the three New Madrid earthquakes might have come from<BR>
the Wabash Valley zone of Southern Illinois and Indiana.<BR>
<BR>
"...which would sort of make it a triggered earthquake, triggered by the<BR>
New Madrid activity. But there's no question that the sequence was<BR>
overwhelmingly in the New Madrid seismic zone. So the idea that, Oh we were<BR>
wrong and the activity was in Illinois, that's just not what the study ever<BR>
said."<BR>
<BR>
How a theory that introduces the question of one quake being the result of<BR>
a trigger becomes a treatise that revises the entire location of a major<BR>
earthquake sequence is a testament to the power of rumor.<BR>
<BR>
But it's that nugget of truth that fascinates scientists.<BR>
<BR>
"That's one of the relatively newer ideas, that it might be remotely<BR>
triggered." This is Professor Lynne Leasure, a western Kentucky native and<BR>
a geologist who recently retired from Murray State University's department<BR>
of geosciences.<BR>
<BR>
"There was possibility that one of the earthquakes in this series might<BR>
have occurred in Southern Illinois. They do have surface evidence of<BR>
sandblows. And the sandblows are very common in southeast Missouri from<BR>
this event."<BR>
<BR>
Sandblows, in this context basically result from the ejection of fluidized<BR>
sand in water-saturated sediments during an earthquake. They're associated<BR>
with liquefaction, in layperson's terms, when land takes on a liquefied<BR>
state.<BR>
<BR>
Dr. Hough says the trigger theory could also explain the shocks felt in the<BR>
Louisville area at the time of the New Madrid series.<BR>
<BR>
"There's actually very compelling evidence that there were triggered<BR>
earthquakes near Louisville, Kentucky. A couple of them, I think you can<BR>
identify from these accounts. And so this fits in with our new recognition<BR>
that you do get triggered earthquakes, or you can get them after you have a<BR>
big main shock."<BR>
<BR>
One such earthquake account, she says came from a young Zachary Taylor, the<BR>
future president and then-Army officer in Louisville.<BR>
<BR>
"...and he described one of the earthquakes and this tumultuous shaking,<BR>
and one of his buddies jumped out of a window and hurt his leg, and<BR>
chimneys were toppling."<BR>
<BR>
Dr. Hough says, at the end of the day, scientists are still looking into<BR>
these questions.<BR>
<BR>
"The January main shock... I can present evidence for why the Wabash valley<BR>
is a plausible source. But the truth is that we really can't constrain the<BR>
location of that event. It could have been in Western Kentucky. It could<BR>
have been in New Madrid. But the observations just aren't as strong."<BR>
<BR>
Dr. Hough's more recent research proposes that the New Madrid tremors<BR>
weren't as huge as people thought, with magnitudes closer to 7 than to 8.<BR>
<BR>
For WKMS News, I'm Jacque Day<BR>
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