Posted on 04/18/2008 2:45:28 AM PDT by dinoparty
Decatur, Illinois
My wife and I just felt a very noticeable earthquake.
I’m from Danville. Earthquakes are not too common around here, are they?
I lived in California for 26 years, and this is the strongest earthquake I have ever felt! Hahahaha.
I picked a heckuva day to quick popping amphetamines.
/airplane
Felt it here in Indianapolis. Larger than the last one.
That’s what I felt in Nashville. My first one too. Felt like about 5 sways.
Hi Neighbors
nothing like a damn earthquake to bring us together!
Woke us up in Portland.
Take a deep breath.
It wasn’t a 12 or anything
We are in Portland
Tennessee
But the coffee isn’t ready yet.
Wabash River Fault Zone is an identified seismic hazard, and is believed from paleoseismic evidence to have generated quakes up to M 7.5 several thousand years ago.
http://www.sciencedaily.com/releases/2003/05/030515075354.htm
Ancient Fault Lines May Have Become Re-activated
ScienceDaily (May 15, 2003) — On June 18, 2002, a magnitude 5.0 earthquake occurred in southern Indiana, followed by a 1.2 magnitude aftershock on June 25, 2002. Because the region of occurrence, the Wabash Valley Seismic Zone, is seismically active, Dr. Won-Young Kim, a seismologist with the Lamont-Doherty Earth Observatory at Columbia University, conducted research to determine the potential hazard of future earthquakes to this region. His findings suggest that an ancient fault line dating back to the Precambrian era of geological history (from 4.6 billion to 570 million years ago) has become reactivated and was the likely cause of the June 2002 earthquakes. Kim is presenting his findings at the Seismological Society of America in May, and publishing in the Bulletin of the Seismological Society of America.
Through analysis of high-quality broadband waveform data from the June 18 earthquake, Kim determined that the earthquake’s epicenter occurred at a depth of 18±2 km (11.2 miles) below ground level, deeper than most earthquakes in stable continental regions. By combining this location with the June 25 aftershock, which occurred at 20 km depth, Kim suggests that the earthquakes can be attributed to a steeply dipping fault, known as the Caborn Fault, associated with a rift system once responsible for the breakup of an ancient supercontinent.
“Old continental crust contains a billion-year record of past tectonic activity. This area was once as seismically active as the Gulf of California is today,” said Won-Young Kim. “The reactivation of this fault may be due to the forces that are moving the North American Plate over the Earth’s mantle. The depth of this earthquake suggests that these forces are quite large, even though they far away from present plate boundaries.”
The June 2002 earthquake is one of the largest seismic events instrumentally recorded for the Wabash Valley Seismic Zone, which extends to southeastern Illinois, southwestern Indiana and parts of western Kentucky. This zone is considered a source of strong earthquakes with geological evidence of prehistoric earthquakes of up to magnitude 7.5. The Wabash Valley Fault System, a fault system within the Seismic Zone, is probably the best documented fault system in the eastern United States due to past petroleum exploration in the area, yet seismologically it is poorly understood. It is known that many of the Wabash Valley faults extend into rocks from the Precambrian era, to at least 7 km depth.
Kim’s research is the first to directly correlate an earthquake with one of the known faults in the Wabash Valley Fault System. His findings suggest that the strike-slip faulting on this Caborn fault was happening on a near vertical fault plane at 18 km depth, indicating that ancient buried faults associated with a possible Precambrian rift system are being reactivated by contemporary compressive stress.
“We don’t yet understand how faults are reactivated, but it appears that some pre-existing faults are more likely to break than others. The study of this sequence should help us to determine the likelihood of future occurrences. More research on these anomalous quakes is required,” said Kim.
Earthquake rattles Tri-State
An earthquake measuring magnitude 5.4 with an epicenter in Southeastern Illinois rattled the Tri-State in the early morning hours Friday.
The shaking, which started at about 4:35 a.m. CDT, lasted about 10 seconds.
A reporter at the Associated Press building in downtown Indianapolis reported feeling the earthquake as well. Scott Rosenburgh, a former Courier & Press advertising manager now working in a suburb northwest of Chicago, said the quake woke him there. No damage has been reported to police dispatch yet. More information will be posted as it becomes available.
Is everybody in STL up at this time of day? Sheesh! Guess it takes an earth quake to find out who my FReeper neighbors are...
wow...never felt a tremor before up here, mom thought i was shaking the house or somethin lol.
Felt the earthquake here in Advance, Missouri.
Last earthquake I felt in this area must have been around 1980.
The New Madrid Seismic Zone, so named for the quake in New Madrid, lies within the central Mississippi Valley. It extends from northeast Arkansas, through southeast Missouri, western Tennessee, western Kentucky to southern Illinois.
LOL!!!
Got me there. Oh well...
It woke us up.
I would've said it lasted a minute.
HF
I’m on my way to the coffeepot.
That has to be the New Madrid fault line area.
LOL...I was already up, but it did wake some people around here.
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