Ah, I actually RTFA :
"the annual number of earthquakes record at magnitude 3.0 or higher in the central and eastern United States has increased almost tenfold in the past decade â" from an average of 21 per year between 1967 and 2000 to a maximum of 188 in 2011. "
I don't think one needs a statistical test for those data. The trend is pretty clear.
You RTFA, and managed to miss that this is unrelated to fracking? I work in the oil and gas industry, so include me among the biased I guess, but I also understand oil and gas production so I'm here to tell you that it is injecting wastewater into fault lines that is causing earthquakes. Not fracking, not oil production, not gas production, but what we call "disposal wells."
In many areas of the USA, water is a scarce commodity, so there aren't any injection wells even though there is lots of fracking.
In many areas of the USA, there is water injection going on in order to "wash out" remaining oil in old formations. These wells are not hydraulically fractured shale formations (the "controversial" process). This has been going on for nearly 100 years.
A Geophysicist I know who works for a large independent oil & gas producer maintains that it has been known for about 20 years that injection wells can cause earthquakes by lubricating fault lines. Extensive testing was done during fracturing at multiple sites and the study was not able to find any data supporting a link between fracking and earthquakes. The instruments used were geophones, which are ultra-sensitive accelerometer devices normally purposed for analyzing formations by echolocation.
All of the comments I see so far clearly didn't click links.. the links mention geothermal production and water injection, the summary indicates that somehow natural gas is extracted by pumping fluid in the ground. That is only true for oil production. In natural gas production our aim is to deliquify wells so that the water isn't exerting backpressure on the gas production, slowing it down and eventually stopping it altogether. Disposal wells are only sometimes used, to get rid of the nasty, brackish, useless water produced from all kinds of hydrocarbon wells.