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.
Recent Examples of fracking from the Web. 1  A city moves to ban hydraulic fracking or the use of plastic shopping bags or puppy mills or sugary drinks, and then the state smacks them down. 2  QuickTake explainers on OPEC, what drives oil prices and fracking.