Hi Lowell. Pumping fluids into the ground at high pressure has played a major role in geothermal power generation, oil production, solution mining, and hazardous waste disposal. The first well-documented case of triggered seismicity due to fluid injection occurred at the Rocky Mountain Arsenal near Denver, Colorado during the early 1960's, where there was no previously recorded seismicity. Following these earthquakes, a fluid-injection experiment carried out in Rangely, Colorado, in a producing oil field proved that injecting high pressure fluids into geologic formations under the right conditions of stress could trigger earthquakes.

In several locations, earthquakes and faulting have also accompanied fluid extraction. These earthquakes occur particularly in large shallow hydrocarbon fields from the release of stresses built up throughout the producing region as reservoir fluid pressures are reduced. Contraction of the reservoir rock drives the rock above and below the producing layer into compression, while rocks on the edge of the producing field extend since they are not displaced as much as rocks directly above. Examples of seismicity probably triggered by fluid extraction include Goose Creek, Texas; Buena Vista Hills, California; Rocky Mountain House, Canada; Lacq, France; Fashing, Texas; and probably the clearest example, Willmington oil field, California.

"Mining activities involve the removal of mass from a continuos body and easily can change physical conditions in the surrounding rock. Mine excavations act as stress concentrators, often leading to increases in seismic activity ranging from microseismic acoustic emissions to full scale tremors with magnitude of 5. Mine seismicity includes spallations, tunnel collapse, gas outbursts, "bumps," and rockbursts, as well as real earthquakes. Some examples of mine-induced seismicity include Wappinger's Falls, New York, in a dolomitic limestone quarry reaching a depth of about 50 meters and surface area of about 1 square kilometer and in the Belchatow trench, Poland, at a large strip mining operation centering on brown coal at about 200 meters depth.

With mans intrusion into the earth I'm surprised that we don't see more triggered earthquakes
Then we do. Then again maybe there are more man triggered earthquakes and we don't know it. Take Care…Don in creepy town