This is what a man-made earthquake sounds like. It's from Oklahoma (magnitude 5.6). I recorded it this morning here at Pigeon Hill in Steuben, Maine. About 7 seconds into the sound clip you can hear a California earthquake (also 5.6). The Oklahoma quake begins at about 24 seconds.
Oklahoma used to be a quiet place. In just a few years' time the fracking industry has turned it into one of the most seismically active — and riskiest — regions in North America, second only to Alaska.
Is this really the world we want to create for ourselves?
Recorded at Pigeon Hill, Steuben, Maine with a Nanometrics Trillium 120PA broadband seismometer. To make this audio clip, the original signal was up-shifted by about 11 octaves (x1800). This 32-second clip spans 16 hours of real Earth time. The recording starts at 20160903 00:00:00 UTC.