February 7 was the multi-state earthquake drill known as the Great Central U.S. ShakeOut that was observed by several states in the central part of the U.S. -- including Illinois. Not only is February 7, 2012 the 200-year anniversary of the last and largest of the great shakes that were part of the New Madrid earthquakes of 1811-1812, but Tuesday saw two earthquakes in states observing the ShakeOut.
According to the United States Geological Survey, a 3.1 magnitude earthquake shook Oklahoma at 10:29 a.m. local time with an epicenter six miles south of Paden. This location is 55 miles east of Oklahoma City.
This earthquake had a shallow depth of 3.1 miles.
Earlier, just after midnight -- a 2.5 magnitude quake was registered in southeastern Missouri -- just north of the Bootheel with an epicenter nine miles northeast of Greenville. This epicentral location is 99 miles south of St. Louis and 31 miles north of Poplar Bluff.
This small earthquake had a poorly constrained shallow depth of about .1 mile.
Earthquakes that strike east of the Rocky Mountains -- in the central and eastern U.S. are typically felt over a wider area than same-sized earthquakes west of the Rockies, such as in California.
The Missouri earthquake was located within the Illinois basin-Ozark dome seismic zone that lies just north of the New Madrid Seismic Zone and encompasses most of central and southern Illinois, part of southeast Missouri, southern and central Indiana, part of western Kentucky as well as a portion of northern Arkansas.
According to the USGS, the historic New Madrid quakes were undoubtedly felt in the same areas as today's earthquakes in Oklahoma and Missouri. Southern Illinoisans were likely to have also felt the shaking during the 1811 and 1812 quakes.
If you did not participate in Tuesday's earthquake preparedness drill, it's not too late to plan ahead and prepare anyway. Participation in the ShakeOut is not necessary to prepare for an earthquake in the Marion area, southern Illinois or any surrounding states. A large enough quake in an adjoining state would affect southern Illinois residents in many ways such as interruption in communications, transportation and commerce.
What are you doing to prepare? Small quakes are simple reminders that we never know when a large tremor can strike and our only defense is to be ready. Make a plan, make an emergency kit, know what to do in the event of an earthquake and talk to your family so you are prepared.
Do you live anywhere near the epicenters of Tuesday's Oklahoma and Missouri earthquakes? Did you feel anything? Leave a comment and let me know!
Comments