Earthquake Spurs Chatter
Whether you felt the morning quake (coeds at Shawnee State did) or not (Tim and Keith were sound asleep dreaming of birdies and eagles), you no doubt are using today’s earthquake as a conversation piece. After all, save for the weak tremor near Pritchard a few years ago, it has been since June 2002 that a decent sized earth movement occurred along the New Madrid Fault (the rift under the earth’s surface near the Mississippi River centered in New Madrid Missouri).
I talked to Dr. Ron Martino of Marshall’s Geology department for the skinny. What I found surprised me!
First, today’s quake registered 5.2-5.4 on the Richter Scale and was felt as far away as Ontario Canada. Once quakes reach 5.0, geologists stand up and take notice. “Quakes up to 5.5 are not uncommon in our region. And big ones have affected South Carolina and New England in the past 75 years”, Dr. Martino told me.
In fact, as recently as 1980 in Maysville Ky. and 2002 in Evansville In., 5.0+ magnitude quakes have rattled the Ohio Valley. These small quakes can be indicators of stronger seismic action in the future.
What floored me was what Martino told me next. “In 1811-12, major quakes in the mid 8 range shook the New Madrid crevice. That was back before the population explosion in the Ohio Valley territory and for that matter in America. An 8.0 quake near Louisville or Memphis in 2008 would be catastrophic since the building integrity here in the east is not even close to that out west”!
Ron went on to add that the USGS (Geological Survey) has credible evidence to support the notion that a quake like that will occur in the next 100-200 years.
On final note, when comparing magnitudes on the Richter Scale, remember a logarithmic scale is used. This means for every one unit up in magnitude, you are increasing the ability to move the earth by 10 and the power of the quake by 30.
So today’s quake was say 5.2. If a quake reached 6.2 this weekend, it would have 10 times the ability to move the earth with 30 times the damage capability. If the magnitude reached 7.2, then you will have 10 times 10= 100 times the ability to move the earth when compared to a 5.2 and an astounding 30 times 30= 900-fold increase in the energy or power imparted to the land.
With that in mind, here are some famous earthquakes and their magnitudes for comparison. Be glad you were not at Candlestick Park in 1989 when the A's and Giants were about to play game number 3 in the World Series when the 6.9 quake hit!
Friday, epicenter So. Ill 5.2
2002, Evansville, In 5.0
2001, Seattle 6.4
1994, LA 6.7
1989, San Fran 6.9 (World Series)
And a final word on the New Madrid Fault. Dr. Martino tells me the fault has its origin back during the Jurassic era some 250 million years ago when the dinosaurs roamed the earth. The fault is related to the pulling apart of North and South America!