Magnitude 3. Big deal. That's what happens when you break rocks -- they shake around a bit. In fact, I'd say gas fracking is earthquakes -- you characterize what you're doing underground using a seismometer and picking up the vibrations.
Saying "but if fracking can cause small earthquakes, might it not one day cause a large one" is a bit like saying "if your cat can devour a mouse, how do we know it won't one day devour an entire city?"
Pretty sure we have the experience to know our cats aren't going to devour our cities, but it seems like a lot of what happens due to fracking we're still figuring out.
And most of the information geologists are using comes from investigating the earthquakes around the Geysers geothermal plan in California.
The conclusion was that removing material from underground and not replacing it with supporting structure causes subsidence, and depending on the structure, punctuated subsidence which is basically code for an earthquake.
Draining aquifers has a similar effect although the rate at which an aquifier is drained is less noticeable.
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[ 3.6 ms ] story [ 14.1 ms ] threadSaying "but if fracking can cause small earthquakes, might it not one day cause a large one" is a bit like saying "if your cat can devour a mouse, how do we know it won't one day devour an entire city?"
[1]:http://www.woai.com/news/local/story/Could-fracking-be-at-fa...
The conclusion was that removing material from underground and not replacing it with supporting structure causes subsidence, and depending on the structure, punctuated subsidence which is basically code for an earthquake.
Draining aquifers has a similar effect although the rate at which an aquifier is drained is less noticeable.