http://www.earthquakes.bgs.ac.uk/earthquakes/education/faqs/faq6.html

Here in South Wales we get several of the 1.5 magnitude quakes (imperceptible to people) that caused Cuadrilla to stop fracking near Blackpool every year, along with a couple of the barely perceptible 2-2.9 category. In the Lifespan a fracking operation, we would almost certainly experience several 3-3.9 and be quite likely to see something more significant too (see below). This is irrespective of any role that the actual fracking might have in increasing earthquake incidence and severity.

As for more detail on South Wales:

In South Wales, on the other hand, although a line of epicentres of significant events can be traced from Pembroke (an earthquake in 1892) to Newport (active in 1974), only the Swansea area shows consistent recurrence, with significant earthquakes occurring in 1727, 1775, 1832, 1868 and 1906. (Given this periodicity it may be that a further earthquake in this area is due in the near future.) http://www.earthquakes.bgs.ac.uk/hazard/Hazard_UK.htm#space (again)

This line of significant epicentres goes straight through the licenced areas the frackers have their sights on.

See map here: http://www.earthquakes.bgs.ac.uk/hazard/Hazard_UK.htm#space

This map shows that there were known earthquakes in the Fylde area where Cuadrilla have ground to a halt. The stakes are so high they will always take the risk. They bank on catastrophe not happening until after they are out of the area. But they know it can always happen and, as with BP in the Gulf recently, have large contingency funds and such massive profits that they can just shrug it off in next to no time.

The whole safety case of fracking operations rests on the integrity of the well casings – made largely of ……. Cement! Ignoring the near practical impossibility of lining boreholes that are many hundreds of meters long and bent with cement that has no weak spots or imperfections, cement is hardly renowned for its flexibility and ability to withstand shocks, so given the shocks induced by the explosions used in fracking and the whole scale shock waves of natural seismic activity, who gives any credence to the guarantees of operators whose merest sense of responsibility causes them to shut down operations after a piddly 1.5 quake?

Remember, the Richter scale is a logarithmic scale. Scale 2 is 10 time the size of a scale 1. Scale 3 is ten times scale 2, or 100 times scale 1, etc.

FRACK CHEMICALS

Cuadrilla downplay the nastiness of their frack fluid: http://www.cuadrillaresources.com/what-we-do/technology/fracturing-fluid/
Look more closely at what they say. “The fracing fluids used by Cuadrilla is 99.75% composed of fresh water and sand. This water and sand combination is supplemented with microscopic amounts of everyday chemicals typically found in peoples homes.” ; would you go around drinking the things under you sink or in your shed or garage?

They list the ingredients thus:

• 99.75% = Water and sand
• 00.125% = Hydrochloric acid
• 00.075% = Polyacrylamides
• 00.005% = Biocide

Firstly, do the math. That adds up to a mere 99.955%. Leaving 0.045% completely unaccounted for. The list of candidates is extensive and nasty. Some are listed here: http://en.Wikipedia.org/wiki/Hydraulic_fracturing

Makes you wonder when they list hydrochloric acid openly. This is known to have a corrosive effect on human tissue, with the potential to damage respiratory organs, eyes, skin, and intestines. http://en.wikipedia.org/wiki/Hydrochloric_acid#Safety

As for polyacrimides, concerns have been raised that polyacrylamides in the environment may contaminate food with the nerve toxin acrylamide. While polyacrylamide itself is relatively non-toxic, it is known that commercially available polyacrylamide contains minute residual amounts of acrylamide remaining from its production, usually less than 0.05% w/w. Additionally, there are concerns that polyacrylamides may de-polymerise to form acrylamide. In dilute aqueous solution, such as is commonly used for Enhanced Oil Recovery applications (and fracking!), polyacrylamide polymers are susceptible to chemical, thermal, and mechanical degradation. http://en.wikipedia.org/wiki/Polyacrylamide

As for biocide! What do you need to know beyond the fact that the term covers anything that kills living things!!

Returning to Cuadrilla’s own words: “Upon returning to the surface, they [frack fluids] are stored in steel tanks and at no point come in contact with the ground. In the unlikely event that any liquid was spilt on the surface, seepage at ground level is prevented by the installation of an impermeable membrane on land at and surrounding the well site.”
Bloody hell!! They do sound dangerous, don’t they? Expensive precautions for something we are not supposed to worry about, wouldn’t you say?