On 5/19/2012 8:01 AM, Brett Nordgren wrote:
> Hi Thomas,
>
> I would think that they should count.  They are real quakes, releasing 
> strain energy which has been building up over time.  It's just that 
> they were artificially triggered well before they would have naturally 
> occurred.  I think the best current opinion is that they are usually 
> not triggered by the hydraulic fracturing operation itself but rather 
> by the associated water-disposal wells which can serve to lubricate 
> and weaken any nearby faults.
>
> In mine blasting the vibration energy source is not geological but 
> chemical.
>
> Brett
>
> At 05:21 PM 5/18/2012, you wrote:
>> I wonder if anyone has an opinion on this subject or even cares. 
>> Years ago, I was told not to post mine blasting. Now, a new era is on 
>> us. Are we going to consider fracking/induced earthquakes as 
>> earthquakes are treat them as if they were "human induced" like mine 
>> blasts? Certainly not all the waveforms of a typical earthquake are 
>> produced in these events. When the Arkansas earthquakes started I 
>> faithfully posted those that were three and above. Now we know that 
>> 95% of those quakes were induced. A comment from the floor a week or 
>> so ago (Menlo Park...USGS podcast) was accepted with qualification 
>> when he said that chances are two mag 5 quakes already this year  in 
>> the mid-continent region were induced. I suppose quakes in Texas, New 
>> York State and the Washington, D.C. area are suspect too. And then 
>> the latest one in Timpson, TX ... was that a real quake? How do you 
>> suggest we separate the "real" from the "unreal"!
>
>
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Brett,
  Your opinion is logical. But....at least two "quakes" listed as 
occuring in Indiana this month are not on faults. The Timpson quake was 
described as "poor" in quality. Who/what is studying such earthquakes? 
What can be gained from the data where much of the wave phases are 
missing or distorted?  Of the last ten quakes listed (at the present) 
for the middle states on Memphis website, only three are(more likely) 
naturally occurring quakes. I am not wanting to appear belligerent 
sounding.  I am raising the question not in an argumentative way but 
trying to understand the scientific value.
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