Sunday, April 3, 2016

State of the Earthquake Union - Oklahoma Earthquakes

Every few months I do a recap of the OK earthquake situation.  I realize that people can't always sift through my thousands of posts, and don't understand what is going on.

Recap - OK is experiencing increasing earthquakes and is on its way to creating a second New Madrid sequence.  (look that up).  The physics underlying the mechanisms of both zones is the same.

What's happening?  In eastern North America (ENA) we have a 'basement' of Precambrian granite gneiss.  It looks and feels like granite.  The US has never mapped this rock, they assume it is solid and uninteresting.  We Canadians live with it at the surface, and we know it has structure.  It formed as a result of continental collision and formed the roots of a gigantic mountain range a billion years ago.  As such, it has very long and deep 'megathrusts', in the NE direction, evenly spaced.  I know where they go, the US does not.

Physics.  Since the last continental separation, the basement has become highly squeezed by tectonic motions, mainly settling into a cooler zone.  The basement is at the limiting stress, or as much as it can handle.  Any disturbance causes earthquakes.  The big earthquake zones are caused by natural seeps, that is fresh water seeping down to the basement megathrusts.  Water and earthquakes go together on the maps.

A natural seep does not create water pressure in the rock.  It is the chemical action of fresh water (a universal solvent) upon quartz grains that causes earthquakes.  In Oklahoma, they are accelerating this process a thousand times, through the deep injection of fresh water.

What can be done?  The USGS is a federal fish thrown to California for votes.  The OK republicans constantly try to eliminate it.  They aren't doing anything for OK.  OK puts in seismometers and the gus feeds off the signals to map earthquakes.  That is the extent of what they are doing, rearranging the deck chairs on the Titanic.  There is no money, OK is bankrupt, and the gus must spend political money to survive.

If there were money, they could easily map the Precambrian by using old oil company data.  They could do rock mechanics tests on the rock.  So many things that will never get done.

My solution - A solution, as done by many states, is to stop all injection.  This would have the result of instantly turning OK back into The Grapes of Wrath, a giant dustbowl.  All those people would have to move to California, where there isn't enough water.  Not good.  My solution is to treat all the water being injected so it doesn't cause earthquakes.  Right now they are injecting at 35 cents a barrel, the externalities (damage caused) is probably $2 a barrel.  Treatment would add maybe 5 cents a barrel.

Probable outcome - We will stand by and watch the train wreck.  OK will eventually hit 'closer' earthquakes that will stop all injection.  With people dead, there will not be any room for water treatment.  We don't know what size the 'closers' will be.  If they are 6's, it will most likely go on to 7's before it settles down.  If the rock totally opens up, the earthquake activity will continue through natural seepage due to all the abandoned open holes.

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