Saturday, April 4, 2015

Oklahoma earthquake dilation - It's BACK!

Yeah, as long as there are no earthquakes in the OK zones for 2 days, then my dilation theory is back on the table.  As you recall, there was a pattern of 'quenching', where things built up for a few days, and then a larger earthquake would occur and quench all activity for a while.  I used this to demolish the unstated hypothesis of the usgus, in my huge physics article.

Then the intense activity started again, and completely stopped, until just recently.  My theory was diving in flames!  But this earthquake has allowed it to pull out of the dive with all engines restarted.   Because my local guy said it was the biggest ever, I am dismissing the usgus M4.2 and going with the European M4.9.  That means the dilation run-up was much longer, and included that dead spell.  This is exactly how it was described 30 years ago.

A hard-rock fault is very bumpy.  It doesn't really like large earthquakes, but if you inject enough, you can persuade it.

Before the injectors, the fault was very happy, each hill and valley matched.  But things started to push, and the fault must move.  Just like a landslide, there is a heck of a lot of action before the final rupture.  The entire fault must get ready.  For an M5-ish like we just had, we're talking about 300 m of fault.  With slow movement, the fault has to dilate, just like two saw-cut pieced of wood.  The gaps must flood with water which takes some time.  Then it might hover for a while, stopping all distant activity.  If we want a really good super-shear rupture, the whole fault must be at a small critical displacement.

Then the fault ruptures super-shear, which very fast.  It just skips the hills and valleys, and the dynamic friction goes to near zero.  Yahoo!  Just like racing down the hill in an out-of-control toboggan.  That was great fun when I was a kid, and you bent down, and took out the legs of the kids crazy enough to walk up the main slope.  Nothing could stop you!

Case for a deep M5:  It felt worse, but there was no damage.  A deep normal earthquake gives a big deep whoomp, like a badly tuned elevator dropping.  That means an accelerometer would read high displacement, but little PGV.  They don't have those, just el-cheapo seismometers that probably had conniptions and can't read the low frequencies.  This guy will eventually be paired with shallow or deep thrust which really puts out high PGV, and peels bricks.  One reason the big lawsuit will lose in the higher courts is that there isn't any recognizable building code in OK, and the defence will be that of excessive flimsiness.

Update:  Since my fav. muck-raking Tulsa newspaper is silent on all this, I guess they got to them, too.  :(

Update2:  I told the newspaper that I've washed my hands of them for Easter.  They said I'm so unfair!

Update3:  OMG I'm so old!  I can't find the original MIT papers on Google.

Update4:  The Europe guys have revised down to the usgus magnitude.  They have to, since the usgus and their weeny seismometers have official authority.  The real seismometers beg to differ.  :)

Polaris in Southern Ontario recorded it with real seismometers (broadband).  This was not a 4.2

I don't they ever recorded a real 4 from OK.

Here is a true M3.7 from earlier in the day.

It does not exist here.

Update - whatever:  Although I washed my hands of them, Tulsa World has risen with new earthquake muck.  The New York Times can't wait to steal this.  :)

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