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.
Hydraulic fracturing, commonly called fracking, is a drilling technique used for extracting oil or natural gas from deep underground. Fracking is a hotly debated environmental and political issue.Advocates insist it is a safe and economical source of clean energy; critics, however, claim fracking can destroy drinking water supplies, pollute the air and contribute to the greenhouse gases that cause global warming.ow fracking works. Most fracking wells in use today rely on two technologies: hydraulic fracturing, which has been in use since the 1940s, and horizontal drilling, a technique that first became widespread in the 1990s.