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Earthquakes associated with deep well injection—comments and case histories

Craig Nicholson

Published 1992, SCEC Contribution #1577

Under certain circumstances, the increased pore pressure resulting from fluid injection can trigger earthquakes. These injection-induced earthquakes typically result from the reduction in frictional strength along pre-existing, nearby faults caused by the increased formation fluid pressure. Alternatively, massive extraction of fluid or gas can induce sufficient stress and/or strain changes that, with time, can also lead to sudden catastrophic failure in a major earthquake. As each of these different types of triggered events can occur up to several years after well activities have begun (or even several years after all well activities have stopped), this suggests that the actual triggering process may be a very complex combination of effects, particularly if both fluid extraction and injection have taken place locally. To date, more than twenty cases of earthquakes triggered by well activities can be documented throughout the United States and Canada. Based on these case histories, it is evident that, owing to preexisting stress conditions in the upper crust, certain areas tend to have higher probabilities of exhibiting such induced seismicity.

Key Words
United States, seismograms, mining, solution mining, seismology, pressure, geologic hazards, seismicity maps, enhanced recovery, geothermal energy, case studies, engineering geology, fluid injection, Canada, seismicity, maps, pore pressure, secondary recovery, waste disposal, USGS, induced earthquakes, earthquakes, causes, conterminous regions

Nicholson, C. (1992). Earthquakes associated with deep well injection—comments and case histories. Presentation at 33rd U.S. Symposium on Rock Mechanics.