Wednesday, April 17, 2013

Oklahoma earthquakes - the beginning of a mechanism

Ok, OK had me rubbing my temple for a long time.  It is obvious they are injecting into the Precambrian like stink on cheese, and it is obvious they are on the last Grenville Front megathrust.  But why no mechanism?  Our earthquakes are caused by a static high horizontal stress, and weakening faults.  Not at all like California, which has weak faults and a building of stress.

A sustaining mechanism is one which grows to encompass more rock stress.  The biggest one is New Madrid.

It requires a central thrust zone and 2 shear wings.  My intelligent readers would know that this huge mechanism wasn't just placed there in all its glory.  No, it had to grow into the role.  Now it is confined by geology, and may be dying of old age.

But never fear, we can grow new ones!  Arkansas was the perfect proof of this concept.  It started with a central thrust zone, and was growing fine shear wings.  Had they kept injecting, the central thrust zone would have grown, and formed new shear wings.  All to capture more strain energy.

But with OK, we don't have to worry that they will stop injecting!  They had that one M5.6 out on the hanging wall, but that was isolated.  In response to the strain release, more activity appeared on the main megathrust under the city which was starting to form a shear wing.  This was a disconnected system, and under natural conditions, might have died.  But they kept injecting!

Now we suddenly have this huge rip, forming the necessary thrust zone.

The mechanism is off and running!  We should expect at least an M5 on this zone, and then the formation of a new shear wing.  Only time will tell if I'm full of it!  :)

*Note, why doesn't the US see this?  They are full of these little state geological surveys who only focus on their feet.  Couldn't see a continental pattern if it hit them on the nose.  The USGS is too busy tanning in California, and everybody is just trying to stay alive.

Update:  In g+ I thought of my new physics-based game "Grand Theft Injection".  Here's my kickstarter trailer.

You take the role of Rico, a corrupt geologist in the seedy city.  You started working for the Injection Mob when you realized it was the only way you could make money with a general geology degree.  In a first for games, the physics engine goes full 3-D right down to the Moho!  You must bribe corrupt politiciians, hide relevant data, and avoid falling buildings.  The more the Mob gets to inject, the more money you make, and the more earthquakes.  You can also make money as a shady contractor!  Lots of fun and laughs!

Something about the name seems familiar,  hmmm ....

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