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#1 Fracking had nothing to do with these quacks. I live dead center of the three quackes that occured in Irving/Dallas where no fracking/ oil/gas well drilling is allowed within 30 miles from here.
Irving sits on shifting sands. Foundation problems have occured as long as homes have existed.
The reconstruction of several major freeways (114 and now 183) and the current construction of light rail connecting DFW Internatoinal Airport to the DART Transit System requires all supports be supported by drilling down through these shifting sands to bedrook. All of this new, massive constuction is putting strain on what may be a thin layer of bedrook.
What everyone heard here was not the usual rumble that one lady who used to live in California told me she heard during earthquakes in California. What she heard she said was a huge underground snap/boom, followed by a rumble.
A well south of DFW airport is too far from the triangle of quakes, but the new major construction sits right on top of that bedrock.
Posted by Pholulet Thrusomble8588 2012-10-03 09:39||
#2 Pholulet, the article is more correct than you are. Interestingly, I was just reading an article in a technical geophysics journal about induced seismicity and it mentioned the Trigg injection well (on the south edge of DFW) as being the likely culprit for 2-3 small and a dozen micro-quakes several years ago. Injection wells are aimed at large porous sandstones and should not alter geologic conditions in any significant way, and thus should not induce earthquakes. In this case (Trigg well) it seems an unmapped fault was exposed in the injection zone and the injected fluid acted much like the the air in an air hockey table, and allowed the stressed fault to slip more easily. Such techniques for purposely 'managing' earthquakes have been studied for many years, but would be impossible for liability and political (and psychological) reasons.
Bedrock in the Dallas area is not 'thin' - the layer of unconsolidate sands on top of it is relatively thin. Unconsolidated sediment does not support much stress and cannot generate earthquakes. Construction projects only disturb the sediment and a tiny bit of the bedrock - they will not affect faults ~3 miles deep, which is where the Trigg well was injecting. and more or less the depth at which the earlier suspect earthquakes occurred. I have not seen results for the depth of the current set of quakes, nor whether they are along the same fault as the earlier ones, nor whether there is some other injection well in the vicinity - you say there is no drilling allowed within 30 miles, but there are at least 50 wells on the grounds of DFW airport, and the produced fluids are being injected somewhere nearby.
No one is claiming the FRACKING caused the earthquakes - rather it is the injection of produced wastewater (in huge volumes) into a 'normal' well that may have done so. Such responses were well-proven at the Rocky Mountain Arsenal waste injection wells 50 years or so ago.
Oh, the 'snap - rumble' is a normal response of a shallow quake in 'hard' rock near the observer - the snap is the P wave arrival and the rumble the slower moving surface waves.
Posted by Glenmore 2012-10-03 10:51||
#3 No one is claiming the FRACKING caused the earthquakes - rather it is the injection of produced wastewater (in huge volumes) into a 'normal' well that may have done so.
The term "water flooding" is used to describe the injection of water into oil bearing formations to push the oil toward a production well. Water flooding has been done successfully for decades.
Pumping or injecting salt water or waste water from oil wells back into non-producing or 'played out' wells was begun a few years ago when the EPA decided surface ponds and evaporation techniques were unsafe.
Posted by Besoeker 2012-10-03 11:23||
#4 I wonder are micro-quakes like stopping forest burning, you just save up more for a rarer but much larger and more destructive event?
Might make a good SciFi story evacuating San Francisco in order to provoke an overdue "big-one".
Posted by Bright Pebbles 2012-10-03 12:09||
#5 I live dead center of the three quackes that occured in Irving/Dallas where no fracking/ oil/gas well drilling is allowed within 30 miles from here.
What are talking about? I can show half a dozen gas well sites that have been drilled, or are being drilled within four miles of DFW Airport, or closer.
They've been putting in these gas wells and tying the production piping into the existing pipelines for about three years now. You need to get out more. BTW, I live in Foat Wuth, just outside the South entrance to DFW.
Posted by Secret Asian Man 2012-10-03 12:19||
#6 I wonder are micro-quakes like stopping forest burning, you just save up more for a rarer but much larger and more destructive event?
Bright Pebbles, that's pretty much the story. Each increase in magnitude number amounts to something like 30 times more energy released. So if one wanted to 'burn the brush' and prevent, say, ONE magnitude 7 earthquake by releasing the energy in a series of non-destructive quakes (say magnitude 3 or less), it would take 800,000 little quakes. It would be like living on a giant vibrating chair, and cooks would never keep their soufles from falling.
Posted by Glenmore 2012-10-03 12:31||
#7 Must not of been too significant. I was in this area on Saturday--no glass rattling or dishes shaking.
Back home we have small earthquakes of this size routinely without fracking. Of course we are in a fault area. I'll defer to the geologists and petroleum engineers and then I'll take a look at their political agenda.
Posted by JohnQC 2012-10-03 12:42||
#8 Must not of been too significant.
It wasn't. But then, Texans freak out if a half inch of snow falls.
Posted by Secret Asian Man 2012-10-03 13:04||
#9 On the case.
Posted by Mizzou Mafia 2012-10-03 17:19||
#10 It wasn't. But then, Texans freak out if a half inch of snow falls.
Posted by: Secret Asian Man 2012-10-03 13:04
That cold stuff is just some freaky sshit, man!
Posted by AlmostAnonymous5839 2012-10-03 19:45||
#11 Pumping or injecting salt water or waste water from oil wells back into non-producing or 'played out' wells was begun a few years ago when the EPA decided surface ponds and evaporation techniques were unsafe.
True to a point. Long ago we drained waste water from our tanks into adjacent evaporative pits but have for some years been prevented from doing so by regulation. That new regulatory regime did not, however, coincide with the genesis of secondary recovery projects via water injection. Such has been done for a *very* long time utilizing fresh or salt water produced specifically for that purpose and / or waste water produced along with oil. Evaporative pits were a matter of convenience for the disposal of waste water on leases not yet entered into secondary recovery. Now we either transport the water to a lease in secondary recovery and inject it there or transport it to a disposal well where it is injected but not for the purpose of secondary recovery.
Drilling in and around faults is very common since fault slips can provide a type of stratigraphic trap in which commercially viable quantities of oil & gas can become trapped. We've actually drilled straight through faults and later injected liquids into those same wells without incident. While shallow earthquakes can occur as a result of such activity they'll uniformly be of the type witnessed in and around Dallas: so minor as to be measurable but go otherwise largely unnoticed. Of course around here the passing trains, drop forges & blasting at local quarries would tend to mask minor earthquakes should such occur. Beware the siren song of the environazis on this front, there's no real danger since the magnitude of any quakes produced will not reach a level that will cause damage.
Posted by Pliny Unese1004 2012-10-03 23:04||