Fracking earthquakes

In our increasing pursuit of natural gas, it seems we should not only be concerned about fracking up the water supply and fracking up farmland, but fracking earthquakes too. 
Hydraulic fracturing, most commonly known as fracking, involves the use of sand and fluids being injected under high pressure deep into the ground to fracture rock in order to release natural gas. Concerns have been raised about the chemicals used in the fluids and the contamination of underground water supplies; along with the potential to contaminate farmlands and wilderness areas, plus the release of methane – a potent greenhouse gas.
But wait, there’s more..
Some minor earthquakes occurred earlier this year in Blackpool in the UK; in the general area where a company had recommenced their fracking activities. Coincidence? Seems it wasn’t. While rumours and theories of fracking’s involvement have been bandied about for months, it’s now official.
Cuadrilla Resources, the British company exploring for natural shale gas in the Bowland Basin in Lancashire, released a statement a couple of days ago acknowledging a likely connection. 
“It is highly probable that the hydraulic fracturing of Cuadrilla’s Preese Hall-1 well did trigger a number of minor seismic events.”
The earthquakes that occurred were by no means huge, but it’s my understanding they were registering out to quite a distance from the actual fracking site.
The Blackpool tremors also appear to not be isolated events.
The Oklahoma Geological Survey (OGS) has released an Open File Report on another series of incidents that could be linked to fracking. 
Early this year, the OGS received a report from a resident south of Elmore City who said they had experienced several earthquakes the night before. After the OGS examined seismic data, it found dozens of earthquakes had occurred in the area. All were comparatively shallow events occurring a couple of miles away from a gas well.
The OGS says “there is a possibility these earthquakes were induced by hydraulic fracturing”.
I’ve often wondered how the Earth reacts to the various drilling and such we do. When chopping up old mallee stumps for firewood, some of them appear to be impervious to an axe and they are for the most part, but if I hit them in the right spot, the axe will go through like butter. A small force, correctly applied can generate big results.
What will happen if a major weakness is given a “tap” by fracking? It’s a butterflies, dust devils and bunnies type scenario. 
Fracking is a hot topic in the USA as it is here in Australia. Companies here are rushing to set up Coal Seam Gas (CSG) operations on prime agricultural land. Some areas are dotted with gas wells – it’s a rather disturbing sight.
We seem hell-bent on wringing every drop of recoverable fossil fuel this planet has to offer – even though we now have better understanding of the damage to the environment and the price we and future generations will have to pay. Does it really have to be this way? 
How green is natural gas?