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.
New Map Shows Earthquake Prone Places Across U.S. But fracking-related quake data is not included in this report. This colorful new map from the U.S. Geological Survey shows the areas across the United States that are most likely to experience a significant earthquake in the next 50 years.