Emergency Preparedness and Response

Earthquakes

Earthquakes are sudden and powerful tremors that violently shake the ground. They occur when large pieces of the earth’s crust, or tectonic plates, move. This is caused by a release of stress and pressure buildup. Earthquakes can cause widespread damage to buildings, infrastructure, and people’s lives. Earthquakes pose major health and housing threats as they often result in trauma-related deaths and injuries, along with individual displacement and evacuation from building collapse. Certain injuries can lead to infection if left untreated, while building collapse can lead to homelessness and environmental contamination by chemical or radiological agents. Access to emergency services can be disrupted when healthcare facilities and transportation become damaged during an earthquake. Earthquakes can also trigger fires, landslides, tsunamis, and other natural disasters. 

Definition

The Earth has four main layers: the inner core, the outer core, the mantle, and the crust. The crust and top of the mantle form the outer layer made of large, puzzle-like plates that move slowly. Earthquakes occur when two plates suddenly slip past each other along fractures called faults. These plates continue moving until their rough edges break free, causing an earthquake.

Earthquakes start at the hypocenter below the surface, with the epicenter directly above it. The shaking occurs as stored energy is released in the form of seismic waves. The size of an earthquake, called its magnitude, depends on the fault size and amount of slip, measured by seismographs.

Susceptible Populations

Earthquakes can happen all over the world and occur at any point in time. The resources below can be used to understand where earthquakes occur most often.

Common Locations of Earthquakes 
The Lehman College (CUNY) explains earthquakes, plate boundaries, and where they most commonly occur in the U.S. and the world. [url; Pressbooks]

Earthquakes by State 
Earthquakes tend to happen in locations with major faults that are active. In the U.S., Alaska, California, Hawaii, Idaho, Montana, Nevada, Oregon, Washington, Wyoming, and Utah have the most frequent and powerful earthquakes. Small earthquakes happen all over the country, and different states can feel the effects of earthquakes from the locations where earthquakes occur the most. The World Population Review lists and ranks states with the most earthquakes during 2023 from highest to lowest. [url; World Population Review]

Rank	State	Rank	State
1.	Alaska	16.	Colorado
2.	California	17.	Maine
3.	Hawaii	18.	Arizona
4.	Texas	19.	Arkansas
5.	Nevada	19.	Kansas
6.	Wyoming	21.	Georgia
7.	Washington	21.	South Carolina
8.	Oklahoma	23.	Kentucky
9.	Utah	23.	New York
10.	Oregon	25.	New Hampshire
11.	Idaho	25.	North Carolina
12.	Montana	27.	Ohio
13.	Tennessee	28.	Nebraska
14.	Missouri	28.	Virginia
15.	New Mexico	28.	West Virginia

 

Federal Programs

These federal programs provide help for state and local governments.

Federal Emergency Management Agency (FEMA)
The National Earthquake Technical Assistance Program (NETAP) is designed to help state, local, territorial and tribal governments obtain the knowledge, tools and support that they need to plan and implement effective earthquake mitigation strategies. The program provides instructor-led training courses. The NETAP Resource Guide for Earthquake Program Managers provides information on how states and territories can request NETAP assistance. [url; PDF]

National Earthquake Hazards Reduction Program (NEHRP) 
The National Earthquake Hazards Reduction Program (NEHRP) leads the federal government’s efforts to reduce the fatalities, injuries and property losses caused by earthquakes. The 2020 National Earthquake Hazards Reduction Program (NEHRP) Provisions Edition Volume I and Volume II are resource documents for earthquake engineering and the improvement of seismic design of buildings. [url; PDF]

Seismic Building Codes

Seismic building codes are sets of regulations governing the design, construction, alteration and maintenance of structures to ensure that they can adequately resist seismic forces during earthquakes. The local government building officials who review design plans, inspect construction work, and issue building and occupancy permits are responsible for code enforcement. Many states and local jurisdictions adopt the model building codes maintained by the International Code Council (ICC). [url; ICC]

The International Codes include the following:

• International Building Code (IBC): This code applies to almost all types of new buildings.
• 2024 International Building Code (IBC) The International Code Council provides seismic design information in Chapter 16, Section 1613 of the IBC digital code. [url; ICC]
• International Residential Code (IRC): This code applies to new one- and two-family dwellings and townhouses of not more than three stories in height.
• 2024 International Residential Code (IRC) The International Code Council provides seismic provision information in Chapter 3, Section R301.2.2 of the IRC digital code. [url; ICC]
• International Existing Building Code (IEBC): This code applies to the alteration, repair, addition or change in occupancy of existing structures.
• 2024 International Residential Code (IRC) The International Code Council provides seismic retrofit information in Appendix A of the IEBC digital code. [url; ICC]

The ICC publishes new editions of the International Codes every three years; many states and localities have adopted them since the first editions were issued in 2000.

FEMA’s document Earthquake Resistant Design Concepts (FEMA P-749) provides information to help both the general public and engineers understand the seismic requirements in U.S. building codes. [url; FEMA]

Funding Resources

Two separate funding opportunities are available through FEMA and NEHRP that administer the FEMA National Earthquake Hazards Reduction Program Earthquake State Assistance Grant Program to increase and enhance the effective implementation of earthquake risk reduction at the national, state, and local levels. [url; FEMA]

Individual State Earthquake Assistance (ISEA) 
FEMA awards non-competitive grants to eligible states and territories with high to very high seismic risks to fund seismic mitigation planning and strategies. [url; FEMA]

Multi State National Earthquake Assistance (MSNEA) 
FEMA awards competitive grants to nonprofit organizations and institutions of higher education that possess the critical skills to develop and implement regional and/or national earthquake risk mitigation activities. [url; FEMA]

Understanding Recent Earthquakes

The articles below describe recent earthquakes and provide details on their impact.

Earthquake from Maine to Virginia 
A geophysicist and assistant coordinator for the Earthquake Hazards Program provides detailed information about the magnitude 4.8 earthquake on the East Coast of the United States. [url; Maine Public; 2024]

Earthquake in Southern California 
The U.S. Geological Survey explains a magnitude 4.1 earthquake centered in southeast Los Angeles. [url; LA Times; 2024]

Sections of This Resource Library

Throughout this resource, you’ll find guidance specific to these topics:

1. Preparing for an Earthquake

   1. Emergency Plans
   2. Emergency Supplies
   3. Make an Evacuation Plan and Know Your Evacuation Zone

2. During an Earthquake

3. After an Earthquake