As part of our work to better understand areas of induced earthquakes, the USGS installs seismometers in areas of increased seismicity, provides hazard estimations, and uses numerical models.
Increasing Rate of Earthquakes Beginning in 2009
![map of central US and bar graph](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/half_width/public/media/images/allCUS.png?itok=u4krIsuH)
The number of earthquakes in the central U.S. has increased dramatically over the past decade. Between the years 1973–2008, there was an average of 25 earthquakes of magnitude three and larger in the central and eastern United States. Since 2009, at least 58 earthquakes of this size have occurred each year, and at least 100 earthquakes of this size every year since 2013. The rate peaked in 2015 with 1010 M3+ earthquakes. Since 2015, earthquake rate has declined. In 2019, 130 M3+ earthquakes occurred in the same region. Nonetheless, this rate is far higher than the average of 25 earthquakes per year. Most of these earthquakes are in the magnitude 3–4 range — large enough to have been felt by many people—yet small enough to rarely cause damage. Damage has been caused by some of the larger events, including the M5.8 Pawnee and M5.0 Cushing Oklahoma earthquakes that occurred in 2016.
This increase in earthquakes prompts two important questions:
- Are they natural, or man-made?
- What should be done in the future as we address the causes and consequences of these events to reduce associated risks?
Shaking intensity from injection-induced versus tectonic earthquakes in the central-eastern United States
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A century of induced earthquakes in Oklahoma?
Reactivated faulting near Cushing, Oklahoma: Increased potential for a triggered earthquake in an area of United States strategic infrastructure
Delayed dynamic triggering of deep tremor along the Parkfield-Cholame section of the San Andreas Fault following the 2014 M6.0 South Napa earthquake
Differentiating induced and natural seismicity using space-time-magnitude statistics applied to the Coso Geothermal field
Myths and facts on wastewater injection, hydraulic fracturing, enhanced oil recovery, and induced seismicity
Hundreds of earthquakes per day: The 2014 Guthrie, Oklahoma, Earthquake Sequence
A century of oilfield operations and earthquakes in the greater Los Angeles Basin, southern California
Increasing seismicity in the U. S. midcontinent: Implications for earthquake hazard
Surface monitoring of microseismicity at the Decatur, Illinois, CO2 sequestration demonstration site
Efforts to monitor and characterize the recent increasing seismicity in central Oklahoma
As part of our work to better understand areas of induced earthquakes, the USGS installs seismometers in areas of increased seismicity, provides hazard estimations, and uses numerical models.
Increasing Rate of Earthquakes Beginning in 2009
![map of central US and bar graph](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/half_width/public/media/images/allCUS.png?itok=u4krIsuH)
The number of earthquakes in the central U.S. has increased dramatically over the past decade. Between the years 1973–2008, there was an average of 25 earthquakes of magnitude three and larger in the central and eastern United States. Since 2009, at least 58 earthquakes of this size have occurred each year, and at least 100 earthquakes of this size every year since 2013. The rate peaked in 2015 with 1010 M3+ earthquakes. Since 2015, earthquake rate has declined. In 2019, 130 M3+ earthquakes occurred in the same region. Nonetheless, this rate is far higher than the average of 25 earthquakes per year. Most of these earthquakes are in the magnitude 3–4 range — large enough to have been felt by many people—yet small enough to rarely cause damage. Damage has been caused by some of the larger events, including the M5.8 Pawnee and M5.0 Cushing Oklahoma earthquakes that occurred in 2016.
This increase in earthquakes prompts two important questions:
- Are they natural, or man-made?
- What should be done in the future as we address the causes and consequences of these events to reduce associated risks?