Earthquake Hazard Overview

Earthquake Overview

An earthquake occurs when a fault suddenly ruptures and releases elastic energy in the form of seismic waves. Rupture begins at the hypocenter (referred to as the epicenter at the surface). Seismic waves can also be generated by volcanic activity, mine blasts, and other natural and manmade sources, but are generally not strong enough to cause damage to the built environment. Magnitude is a measure of the size of an earthquake.

Earthquakes are caused by the slow movements of tectonic plates. Although most earthquakes, especially large ones (magnitude equal to or greater than 8.0), have occurred along plate boundaries, a few strong earthquakes have occurred in plate interiors.

Seismic hazard is the physical phenomenon of an earthquake that can cause damage to the built environment. When an earthquake (fault rupture) occurs, the rupture may continue to the surface and create a surface rupture hazard, which can damage any building or structure built on it. The fault rupture also generates strong seismic waves that propagate along the ground surface and create a ground-motion hazard that can damage or even collapse buildings and other structures.

Surface rupture and ground motion are the primary hazards generated directly by an earthquake. Not all earthquakes generate surface rupture, however; in particular. Ground-motion hazard can affect a large area and is responsible for the majority of the damage from an earthquake. Thus, ground-motion hazard from earthquakes is of major concern.


Earthquake Risk

The National Earthquake Hazards Reduction Program (NEHRP) leads the federal government’s efforts to reduce the fatalities, injuries and property losses caused by earthquakes. Congress established NEHRP in 1977, directing that four federal agencies coordinate their complementary activities to implement and maintain the program. These agencies are:

  • Federal Emergency Management Agency (FEMA)
  • National Institute of Standards and Technology (NIST)
  • National Science Foundation (NSF)
  • U.S. Geological Survey (USGS)

NEHRP also partners with state and local governments, universities, research centers, professional societies and trade associations and businesses.

Learn more about the National Earthquake Hazards Reduction Program (NEHRP).

Learn more from FEMAhttps://www.fema.gov/emergency-managers/risk-management/earthquake


What is the Kentucky Earthquake Risk?

Kentucky is affected by several seismic zones: the New Madrid and Wabash Valley Seismic Zones to the west and the Eastern Tennessee Seismic Zone to the east.


Link to the State Hazard Mitigation PlanEarthquake Risk Assessment for details, maps and mitigation ideas.


Earthquakes in Kentucky: Hazards, Mitigation, and Emergency Preparedness

Link to http://kgs.uky.edu/kgsweb/olops/pub/kgs/SP17_12.pdf.  Produced by the KGS and KYEM.


Learn more about Kentucky Earthquakes from KGShttps://www.uky.edu/KGS/earthquake/


Earthquake Publications


Earthquake Mitigation Activities Dashboard is Live!

The “FEMA NEHRP State Assistance Grant Program: A History of Mitigation Activities” dashboard was recently released to provide the public an overview of how grant money is spent. The activities detailed in the dashboard support local earthquake safety, mitigation, and resilience activities. 

The FEMA NEHRP State Assistance Grant Program makes funding available through annual, non-competitive grants for individual states and territories, and competitive grants to non-profit organizations and institutions of higher education. The purpose is to support the establishment of earthquake hazards reduction programs and the implementation of earthquake safety, mitigation, and resilience activities at the regional, state, and local level. 

The data detailed in the dashboard will be useful for the public to learn more about the earthquake mitigation activities completed over the country in the last several years and to assist State Earthquake Program Managers for ideas as they respond to the Individual State Earthquake Assistance (ISEA) Notice of Funding Opportunity (NOFO).  

For more information on FEMA’s NEHRP Program please visit: https://www.fema.gov/national-earthquake-hazards-reduction-program.