EARTHQUAKE IN MICHIGAN

TODAY'S QUAKE

About an hour ago, at 12:23 PM, Eastern Standard Time, an earthquake shook our Kalamazoo condo.  I went outside to see if the rumble was due to a truck or a plane, but none were in evidence.  No people were on the street for me to confirm the event.  A call to our daughter a half-mile to the East confirmed it, she thought maybe a tree had fallen.  A call to a friend a few miles to the West found she had experienced it, and apparently her dog had alerted her to it a brief time before she felt it.

A niece in Grand Rapids had also felt it.  TV news channels in the area soon reported that it had been reported from Chicago to Detroit with no injuries reported.  Now only minor damage has been reported but government reports indicated it was about 3 1/2 miles deep and just South of Galesburg.  A call to a friend living in the reported area indicated it was quite vigorous when she was outside gardening.  She hadn't heard from her husband who was out planting corn.

Michigan is not known for earthquakes.  Today's was the strongest I have felt.  Others have been barely perceptible and no worse than the vibrations some trucks had made.  I only remember one that shook the house, barely noticeably when I was a child.

WHAT CAUSED IT

There are several possibilities.  The likeliest will probably be stressed when all the data are available to those studying the quake.  Glacial rebound from the disappearance of Pleistocene glaciers may not have fully released built up stresses?  Could a major quake from the other side of the world send out waves through the mantle or other layers of the earth and be focused on Galesburg or Climax?  Could the recent oil and/or gas recovery activity near Climax used injected fracking fluids and triggered the quake?  Are we in line with the Madrid fault that caused a major quake in Missouri over a century ago?  Is it just part of the normal tectonic movements and release of the stresses they cause?

PRIME SUSPECT OR COINCIDENCE?

I think the most likely cause could be fracking, if it has been going on in the vicinity of Climax, Michigan, which is near the epicenter.  It seems that it has been triggering some quakes in Texas and Pennsylvania.  Or are all of those events just a coincidence?  If this is the reason it seems that it will be unlikely to trigger a major quake and accompanying damage, but who knows?  Fracking quakes could also open cracks that might make ground water contamination more easily include fracking fluids.

Joe Engemann     May 2, 2015