Due to a lapse in appropriations, the majority of USGS websites may not be up to date and may not reflect current conditions. Websites displaying real-time data, such as Earthquake and Water and information needed for public health and safety will be updated with limited support. Additionally, USGS will not be able to respond to inquiries until appropriations are enacted. For more information, please see www.doi.gov/shutdown
Between the years 1973–2008, there was an average of 25 earthquakes of magnitude three and larger in the central and eastern United States. This rate ballooned to over 600 M3+ earthquakes in 2014 and over 1000 in 2015. Since 2015 the earthquake rate has declined significantly (364 M3+ earthquakes in 2017), but this is still much higher than the natural earthquake rate.
The USGS is currently studying seismicity that may be induced at 6 locations across the United States. These studies involve earthquake monitoring, examining industrial data, and evaluating any relationships between seismicity and industrial actions.
The USGS is currently developing new methods to evaluate the hazard due to induced earthquakes. These methods will account for the rapid changes in earthquake rate that we have witnessed in the past few years.
The USGS uses numerical simulations of earth processes to: Evaluate the physical relationships between fluid injection and earthquakes at specific sites, and to simulate possible future behaviors of new and ongoing injection projects.
The Central Virginia seismic zone (CVSZ) comprises an area of ~13,000 km2 in the central Virginia Piedmont; seismicity in this zone is relatively frequent, but generally mild in magnitude. The August 2011 event was the largest temblor recorded in the CVSZ since the development of modern seismic monitoring and highlighted how little we actually know about the CVSZ, including: 1) the...