What is a seismic zone, or seismic hazard zone?
Although you may hear the terms “seismic zone” and “seismic hazard zone” used interchangeably, they really describe two slightly different things. A seismic zone is used to describe an area where earthquakes tend to focus; for example, the New Madrid Seismic Zone in the Central United States. A seismic hazard zone describes an area with a particular level of hazard due to earthquakes. Typically, a high seismic hazard zone is nearest a seismic zone where there are more earthquakes, and a lower seismic hazard zone is farther away from a seismic zone.
Another point of confusion is that the California Geological Survey has two sets of maps with the names “Earthquake Hazards Zones” and “Earthquake Fault Zones (Alquist-Priolo)”.
There was also a seismic zone system (0,1,2,3,4) used for building codes that is now obsolete.
Related Content
How do I get earthquake hazard maps for locations outside of the U.S.?
How are engineers working to make roads and buildings safer?
What is the USGS doing to mitigate and respond to earthquake hazards?
Can the National Seismic Hazard Maps be used as an earthquake forecast tool for the near future?
What is the probability that an earthquake is a foreshock to a larger earthquake?
What is the difference between earthquake early warning, earthquake forecasts, earthquake probabilities, and earthquake prediction?
What is the probability that an earthquake will occur in the Los Angeles Area? In the San Francisco Bay area?
How do I decide whether or not to get earthquake insurance?
How do earthquakes affect buildings?
What is the likelihood of a large earthquake at location X? Is it safe to go to X since they've been having a lot of earthquakes lately?
How will my house hold up in an earthquake? Can the USGS send someone out to evaluate my property?
What are the earthquake hazards/risks where I live?
National earthquake information center strategic plan, 2019–23
Executive SummaryDamaging earthquakes occur regularly around the world; since the turn of the 20th century, hundreds of earthquakes have caused significant loss of life and (or) millions of dollars or more in economic losses. While most of these did not directly affect the United States and its Territories, by studying worldwide seismicity we can...
Hayes, Gavin P.; Earle, Paul S.; Benz, Harley M.; Wald, David J.; Yeck, William L.
United States Geological Survey (USGS) Natural Hazards Response
The primary goal of U.S. Geological Survey (USGS) Natural Hazards Response is to ensure that the disaster response community has access to timely, accurate, and relevant geospatial products, imagery, and services during and after an emergency event. To accomplish this goal, products and services provided by the National Geospatial Program (NGP)...
Lamb, Rynn M.; Jones, Brenda K.
Earthquake hazards: a national threat
Earthquakes are one of the most costly natural hazards faced by the Nation, posing a significant risk to 75 million Americans in 39 States. The risks that earthquakes pose to society, including death, injury, and economic loss, can be greatly reduced by (1) better planning, construction, and mitigation practices before earthquakes happen, and (2)...
Seismic hazard maps of Mexico, the Caribbean, and Central and South America
The growth of megacities in seismically active regions around the world often includes the construction of seismically unsafe buildings and infrastructures due to an insufficient knowledge of existing seismic hazard and/or economic constraints. Minimization of the loss of life, property damage, and social and economic disruption due to earthquakes...
Tanner, J.G.; Shedlock, K.M.
The USGS Earthquake Hazards Program - investing in a safer future
Filson, John R.; McCarthy, Jill; Ellsworth, William L.; Zoback, Mary Lou; Stauffer, Peter H.; Hendley, James W.
ANSS-Advanced National Seismic System
Benz, Harley M.; Filson, John; Arabasz, Walter; Gee, Lind; Wald, Lisa USGS National Seismic Hazard Maps
The U.S. Geological Survey (USGS) recently completed new probabilistic seismic hazard maps for the United States, including Alaska and Hawaii. These hazard maps form the basis of the probabilistic component of the design maps used in the 1997 edition of the NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures...
Frankel, A.D.; Mueller, C.S.; Barnhard, T.P.; Leyendecker, E.V.; Wesson, R.L.; Harmsen, S.C.; Klein, F. W.; Perkins, D.M.; Dickman, N.C.; Hanson, S.L.; Hopper, M.G. NEIC - the National Earthquake Information Center
The National Earthquake Information Center of the US Geological Survey has three main missions. First, the NEIC determines as rapidly and as accurately as possible, the location and size of all destructive earthquakes that occur worldwide. Second, the NEIC collects and provides to scientists and to the public an extensive seismic database that...
Masse, R.P.; Needham, R.E.
USGS provides update for the National Seismic Hazard Model
USGS experts recently released a study that incorporates the latest earthquake science findings into an update of the National Seismic Hazard Model for the “lower-48” United States. Read the full report here: https://journals.sagepub.com/doi/full/10.1177/8755293019878199
USGS Authors New Report on Seismic Hazard, Risk, and Design for South America
New seismic hazard and risk assessments can help at-risk communities prepare for future earthquake disasters
New Audiences, New Products for the National Seismic Hazard Maps
New Audiences, New Products for the National Seismic Hazard Maps
Earthquake Hazard Maps Show How the Nation Shakes with Quakes
Friday's magnitude-5.2 earthquake in southern Illinois is a reminder that earthquakes are a national hazard.
New USGS Map Will Improve Earthquake Hazards Assessment in the Bay Area
A new geologic map of surficial deposits in the nine-county San Francisco Bay region that can be used to evaluate earthquake hazards has been released in digital form by the U.S. Geological Survey in Menlo Park.
USGS scientists conduct passive seismic study in the Washita Reach 1
USGS scientists conduct passive seismic study in the Washita Reach 1 study area.
Paleoseismic Investigations in Central VA Seismic Zone
HayWired Scenario ShakeMap
ShakeMap showing intensity of shaking for the HayWired Scenario.
See: http://earthquake.usgs.gov/earthquakes/shakemap/global/shake/haywiredm7....
San-Andreas Fault
Aerial photo of the San Andreas Fault in the Carrizo Plain. By Ikluft - Own work, GFDL, https://commons.wikimedia.org/w/index.php?curid=3106006
US map depicting earthquake loss by county
Figure 3-4
This map depicts annualized earthquake loss by county. The estimated losses consider the value of buildings in each specific area.
Map depicting difference in estimates of earthquake hazards 2002-2014
Figure 4-1
This map depicts the difference in USGS estimates of earthquake hazards across the nation in 2002 and 2014. The new FEMA earthquake loss report includes the 2014 data, while the previous 2008 report includes the 2002 data. The negative values represent a decrease in estimated hazard since 2002 and the positive values represent an increase.