Posted on 06/27/2004 11:23:20 PM PDT by arkady_renko
Hello! 1:15 AM hard shaking Central Illinois!
A_R
The largest Illinois quake ever recorded occurred on November 9, 1968, and measured magnitude 5.4 on the Richter scale...
Here is one site I use a lot.
Gotcha. Thanks for the link.
....I learned the hard way (Northridge) that paper goods (such as T.P.) should be baggied if stored with bottled water. Most of our water containers split and rendered the scoop useless.
A_R
Never felt it (most likely slept through it) in Des Plaines, about 90 miles NW of Ottawa.
I lived in North County San Diego for about ten years and felt plenty of 'em. Never did learn how to tell, however, whether it was a 4-pointer nearby or a 6-pointer further up north.
I remember rolling over one morning thinking we were having a local tremor, and did't find out 'til I got up and turned on the news about the Northridge Quake causing major damage up by LA.
Has anyone verified an epicenter?
Ops4 God Bless America!
I live just east of Joliet in Will county and it woke me up this morning. My wife and I were in the Riverside/Upland, CA area a few years ago when the Hector Mine 7.2 quake occurred. We were about 40-50 miles from the center of that one on the 3rd floor of a hotel and doors were banging open and closed, stuff was flying all over the room. Pretty wild ride, and many aftershocks till morning. Unusual for Illinois, but not unheard of.
Fore-shock???
My sister's mother-in-law inRacine, WI said she felt her bed shake aat about 1:15 this morning. She thought shomeone was in her bedroom, got and investigated, found nothing and went back to bed. When she got up this morning and watched TV, she realized it had to be the earthquake.
Some friends of ours lost 40K worth of stuff just simply due to things falling over throughout their house back in the '89 Loma Prieta (7.1) quake. Meanwhile, at my place, about 6 miles away, all that happened was a guitar that was leaning up against the wall fell over onto the carpet and went slightly out of tune, plus I had to straighten up a couple of paintings. I don't envy you cleaning up after the mess in your case ...
With of course the notable execption of the New Madrid quake which would have been felt with great intensity even as far north as the NE corner of the state. I wonder what those highrises in Chicago will be like when the next truly big one hits?.... :-)
The complete dynamics are still poorly understood. It could well be that as a precursor to a mega quake, events may occur on other faults at either end of a major fault zone. Of particular note in this case, assuming this quake was on the Sandwich Fault, is that this fault is in an orientation so as to be what is known as a conjugate sheer fracture versus the orientation of the New Madrid. It's is similar to what happens when you crush a column of rock, you get two sets of fractures, not quite perpendicular to each other. There is something called a Mohr diagram to depict all of this.
After the Kobe earthquake a panel was set up to review the safety of nuclear facilities and the design guidelines for their construction. The Japanese Nuclear Safety Commission then approved the panel's report. After recalculating the seismic design criteria required for a nuclear power plant to survive near the epicentre of a large earthquake it concluded that under current guidelines such a plant could survive a quake of 7.75 on the Richter scale. The Kobe quake was 7.2.
Since the Richter scale is logarithmic, a 7.75 quake would be over three and a half times times as powerful as a 7.2 quake. I wouldn't call that "pretty close."
UNUSUAL EVENT DECLARED DUE TO EARTHQUAKE REGISTERED ON SITE SEISMIC MONITORS
At 0111, received a Strong Motion Seismic Alarm and received calls from numerous personnel onsite and offsite that they felt ground motion. A GSEP Unusual Event was declared at 01:21 due to a confirmed seismic event Emergency Action Level HU-4. A walk down of various plant areas including the Dike is in progress to determine if any equipment was affected or damaged. During the event, some spurious alarms were received which cleared with exception of the seismic alarm. The seismic alarm will be reset after Station Engineering reviews the seismic data. They observed a 1" water level spike that immediately returned to normal on main control room suppression pool water level recorder and plant process computer. At this time we have received no reports of equipment damage and walk downs are continuing. The earthquake measured 4.5 on the Richter Scale and was approximately 10 miles north of Ottawa, IL. Ottawa is located 10 miles NW of the site. Both Units remained on line and stable.
The NRC Resident Inspector will be notified and the state was notified.
NOTE: See related events 40844 and 40846.
* * * UPDATE ON 6/28/04 AT 0530 EDT FROM D. COVEYOU TO A. COSTA * * *
"This is an update to Event Number 40845. At 0355 CDT the Unusual Event, entered due to confirmed seismic event, was terminated. A walk down of various plant areas has been completed. No equipment damage was identified. The NARS [Nuclear Accident Reporting System] notification for termination was completed at 0405."
The licensee notified the NRC Resident Inspector, the State and local authorities.
Notified by e-mail: Susan Frant (IRO), Thomas Kozak (R3 DO), Frank Gillespie (NRR EO), Pat Hiland (Reg3), and Geoffrey Grant (R3). Also notified FEMA and DHS.
see
http://www.nrc.gov/reading-rm/doc-collections/event-status/event/en.html
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