Thursday, April 10, 2014

Oklahoma earthquakes at intersection

An M4.1 and 3.7

This is the most interesting place to have an earthquake.  If the magnitude for the 4.1 stands, then it is shear, and it is sad that if they knock it down, we won't be able to see that it is thrust.

Anyway, a 4 a day keeps the doctor away!

Update:  Megathrust backslip

Absolutely the same as the recent series.  A weird shear with an extension component.  This produces a very low PGV, and is why people only felt it lightly.  This can happen when the principle stresses intersect a fault at an oblique angle.  I can't see this holding for very long.

One thing about identical earthquakes, is that they have a common stress driver, and will result in a very large shear earthquake.  The probability is simply greater than if the solutions were all over the map.  Get that earthquake insurance!

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