[Island Chris]

I'm curious about the quakes in Oklahoma. A few weeks ago they made a broad N-S zone into Kansas. The other day there were there M4.1 to 4.3 quakes. Today they are spread out as a cloud near and north of Oklahoma City. It seems like there are as many M2.5 and higher quakes in this area than in all of California (although may not be true, especially with aftershocks to the recent M5.1).

So, natural, fracking, or injection wells of fracking?

Chris

[Skywise]

Hi Chris,

Here's a breakdown of the number of quakes per year, since 1980.

35.9N, 97.25W, 500km radius - it picks up a 4.5 in Arkansas and it's aftershocks in 1982.

The activity starts picking up in 2009, about the time that fracking started picking up. Not proof, but certainly strong evidence.

Code:

year - all - 3+
1981 - 4   - 3
1982 - 30  - 25 - 4.5 in arkansas
1983 - 6   - 2
1984 - 8   - 3
1985 - 6   - 3
1986 - 29  - 4
1987 - 22  - 2
1988 - 23  - 3
1989 - 10  - 4
1990 - 5   - 1
1991 - 2   - 2
1992 - 17  - 3
1993 - 3   - 1
1994 - 2   - 1
1995 - 7   - 4
1996 - 4   - 2
1997 - 7   - 5
1998 - 5   - 4
1999 - 4   - 3
2000 - 10  - 7
2001 - 7   - 4
2002 - 10  - 4
2003 - 9   - 2
2004 - 5   - 2
2005 - 5   - 5
2006 - 14  - 5
2007 - 12  - 5
2008 - 35  - 6
2009 - 78  - 22
2010 - 219 - 62
2011 - 373 - 121
2012 - 127 - 41
2013 - 507 - 114
2014 - 320 - 95 - in only 3 months!!

Brian

[Island Chris]

Thanks Brian,

But, to tell a trend, you would have to limit the numbers to completeness: maybe M2.5+ or M3+. Logically, with fracking and the quakes the last few years, there would be some funding to install local networks of seismometers. Someone must know whether it is fracking or injection, because the quakes would be spatially-associated with the injection wells. Or, could fracking and especially injection wells trigger quakes and these quakes trigger other quakes more remote from the injection?

The quakes the past week in Oklahoma were shallow: less than 5 km depth, except a bunch of them were exactly 5.0 km, so likely assigned to that depth in the location program.

Chris