EarthWord – Induced Seismicity

Release Date:

The occurrence or frequency of earthquakes for which the origin is attributable to human activities.

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Image: House Damage from 2011 Oklahoma Earthquake
House damage in central Oklahoma from the magnitude 5.6 earthquake on Nov. 6, 2011. Research conducted by USGS geophysicist Elizabeth Cochran and her university-based colleagues suggests that this earthquake was induced by injection into deep disposal wells in the Wilzetta North field.

Definition:

  • The occurrence or frequency of earthquakes for which the origin is attributable to human activities.

Etymology:

  • Seismos – comes from the Greek for “earthquake”; and induce – to cause (something) to happen or exist.

Use/Significance in the Earth Science Community:

  • Induced seismicity refers to non-tectonic (i.e., non-natural) earthquakes that result from human activities that alter the stresses and strains on the Earth’s crust. There are many activities that can cause induced earthquakes including: wastewater disposal, mining, development of artificial lakes, extraction of fossil fuels, extraction of groundwater, development of geothermal energy, hydraulic fracturing, and subsurface storage of CO2.

USGS Use:

  • The USGS studies induced seismicity to assess earthquake hazards. A particular focus has been the central and eastern U.S., where the number of earthquakes has increased dramatically since 2008. Recent studies have shown that the seismicity in many of these locations is induced by the deep injection of fluids from nearby oil and gas operations. Because USGS periodically issues earthquake hazard assessments for the Nation, our assessments must include this increasingly significant induced hazard. Additionally, USGS is conducting research to determine why some waste water injection sites are susceptible to induced earthquakes, while the vast majority of sites are not. Research aimed at understanding the processes that control the location, rate, and size of induced seismicity will allow humans to mitigate the occurrence of induced earthquakes in the future.

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