First there was the 5.2 magnitude temblor in the early morning hours of Friday, April 18, more precisely at 4:37 am Central Time. Then five and one-half hours later at 10:14 am came a large aftershock of 4.6 magnitude, a mini-earthquake in itself.

Then this morning, April 21, at  12:38 am came an aftershock of magnitude 4.0.

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Although most of us who live in the area are aware of the earthquake and the two large aftershocks; there have actually been 22 aftershocks in Illinois and the region of the initial earthquake.

None of the eleven aftershocks occurring since the magnitude 4.6 on Saturday morning have been very strong, in fact no one I’ve talked to have noticed them except for the larger aftershock early this morning.

Typically, most people do not have earthquake insurance coverage. These events of the last couple of days have no doubt caused many people to reconsider whether this is such a wise strategy, even though the possibly of earthquake damage is still remote. We just don’t experience earthquakes of any consequence very often. And as much as my house shook, nothing came loose or was damaged, inside or outside the house.

The record for earthquake magnitude in Illinois occurred on November 9, 1968. It was a magnitude 5.3 that was felt over 580,000 square miles in 23 states. Reports say that tall buildings in Ontario and Boston felt the shock.

The St. Louis Post-Dispatch has a nice Richter scale graphic that you can select a magnitude range, and by clicking on that range a picture above the Richter scale vibrates according to the magnitude you select. This helps demonstrate how much a building, a tree or a car would shake under that particular magnitude.

 

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