The range of 60-70 decibels sound pressure level is about as loud as normal conversation in 1 meter distance. The distance from the ears to the sound source is very important to the value of the SPL. Scroll down to related links and look at Table of Sound Pressure Levels.
1 Primarily, during the fracking process:  [Earthquakes] were caused by fluid injection during hydraulic fracturing in proximity to pre-existing faults.. 2  Secondarily, via the disposal of fracking wastewater via underground injection.
Fracking (fracing, hydraulic fracturing), or hydrofracking, is a method of mining for natural gas which greatly increases the efficiency of extracting shale gas from the ground. Geological experts claim that shale beds in New York, particularly the Marcellus Shale, contain more natural gas than previously estimated.