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Natural Hazards

The USGS monitors and conducts research on a wide range of natural hazards to help decision-makers prepare for and respond to hazard events that threaten life and property.

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At what magnitude does damage begin to occur in an earthquake?

It isn't that simple. There is not one magnitude above which damage will occur. It depends on other variables, such as the distance from the earthquake, what type of soil you are on, etc. That being said, damage does not usually occur until the earthquake magnitude reaches somewhere above 4 or 5.Learn more: Earthquake Magnitude, Energy Release, and Shaking Intensity

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At what magnitude does damage begin to occur in an earthquake?

It isn't that simple. There is not one magnitude above which damage will occur. It depends on other variables, such as the distance from the earthquake, what type of soil you are on, etc. That being said, damage does not usually occur until the earthquake magnitude reaches somewhere above 4 or 5.Learn more: Earthquake Magnitude, Energy Release, and Shaking Intensity

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What does an earthquake feel like?

The way an earthquake feels depends on where you are, where the earthquake is, and how big the earthquake is:A large earthquake nearby will feel like a sudden large jolt followed quickly by more strong shaking that may last a few seconds or up to a couple of minutes if it's a rare great event. The shaking will feel violent and it will be difficult to stand up. The contents of your house will be a...

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What does an earthquake feel like?

The way an earthquake feels depends on where you are, where the earthquake is, and how big the earthquake is:A large earthquake nearby will feel like a sudden large jolt followed quickly by more strong shaking that may last a few seconds or up to a couple of minutes if it's a rare great event. The shaking will feel violent and it will be difficult to stand up. The contents of your house will be a...

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How are engineers working to make roads and buildings safer?

Earthquake engineers are working to make roads and buildings safer in the event of a major earthquakes. This includes both improving the design of new buildings and bridges as well as strengthening older units to incorporate the latest advances in seismic and structural engineering. The Federal Emergency Management Agency plays a central role in funding research and development for the purpose of...

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How are engineers working to make roads and buildings safer?

Earthquake engineers are working to make roads and buildings safer in the event of a major earthquakes. This includes both improving the design of new buildings and bridges as well as strengthening older units to incorporate the latest advances in seismic and structural engineering. The Federal Emergency Management Agency plays a central role in funding research and development for the purpose of...

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How do I get earthquake hazard maps for locations outside of the U.S.?

We know of no current "zone" designations for sites outside of the United States. For locations outside the United States for which seismic design is required for military facilities, there exists a standard based on probabilistic spectral ordinates in the manner of the International Building Code and are declared to reflect the 2015 version of that code. These spectral ordinates can be found in...

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How do I get earthquake hazard maps for locations outside of the U.S.?

We know of no current "zone" designations for sites outside of the United States. For locations outside the United States for which seismic design is required for military facilities, there exists a standard based on probabilistic spectral ordinates in the manner of the International Building Code and are declared to reflect the 2015 version of that code. These spectral ordinates can be found in...

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What is the USGS doing to mitigate and respond to earthquake hazards?

The U.S. Geological Survey performs the following functions related to earthquake hazard mitigation:Receives, analyzes, maintains, and distributes data on earthquake activity worldwide. Satellites link our National Earthquake Information Center in Golden, Colorado to a network of seismograph stations. These stations, located throughout the world, are maintained by the U.S. Geological Survey, State...

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What is the USGS doing to mitigate and respond to earthquake hazards?

The U.S. Geological Survey performs the following functions related to earthquake hazard mitigation:Receives, analyzes, maintains, and distributes data on earthquake activity worldwide. Satellites link our National Earthquake Information Center in Golden, Colorado to a network of seismograph stations. These stations, located throughout the world, are maintained by the U.S. Geological Survey, State...

Learn More

Can the National Seismic Hazard Maps be used as an earthquake forecast tool for the near future?

Not really. The USGS Seismic Hazard Maps website and the Unified Hazard Tool (for building custom maps) are designed to display the probability of different events that might occur in a several-year to several-decade period. The model bases all probability estimates on the average rate of earthquakes over long periods of time.As you shorten the time window, you should expect greater and greater...

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Can the National Seismic Hazard Maps be used as an earthquake forecast tool for the near future?

Not really. The USGS Seismic Hazard Maps website and the Unified Hazard Tool (for building custom maps) are designed to display the probability of different events that might occur in a several-year to several-decade period. The model bases all probability estimates on the average rate of earthquakes over long periods of time.As you shorten the time window, you should expect greater and greater...

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What is the difference between earthquake early warning, earthquake forecasts, earthquake probabilities, and earthquake prediction?

The USGS uses these four terms to refer to four different things.Early warning is a notification that is issued after an earthquake starts. Probabilities and forecasts are comparable to climate probabilities and weather forecasts, while predictions are more like statements of when, where, and how large, which is not yet possible for earthquakes.Here are more detailed descriptions of each...

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What is the difference between earthquake early warning, earthquake forecasts, earthquake probabilities, and earthquake prediction?

The USGS uses these four terms to refer to four different things.Early warning is a notification that is issued after an earthquake starts. Probabilities and forecasts are comparable to climate probabilities and weather forecasts, while predictions are more like statements of when, where, and how large, which is not yet possible for earthquakes.Here are more detailed descriptions of each...

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What is the probability that an earthquake is a foreshock to a larger earthquake?

Worldwide the probability that an earthquake will be followed within 3 days by a large earthquake nearby is somewhere just over 6%. In California, that probability is about 6%. This means that there is about a 94% chance that any earthquake will NOT be a foreshock. In California, about half of the biggest earthquakes were preceded by foreshocks; the other half were not. At this time, we cannot...

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What is the probability that an earthquake is a foreshock to a larger earthquake?

Worldwide the probability that an earthquake will be followed within 3 days by a large earthquake nearby is somewhere just over 6%. In California, that probability is about 6%. This means that there is about a 94% chance that any earthquake will NOT be a foreshock. In California, about half of the biggest earthquakes were preceded by foreshocks; the other half were not. At this time, we cannot...

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What is the probability that an earthquake will occur in the Los Angeles Area? In the San Francisco Bay area?  

Los Angeles area:Within the next 30 years the probability is:60% that an earthquake measuring magnitude 6.746% that an earthquake measuring magnitude 731% that an earthquake measuring magnitude 7.5will occur in the Los Angeles region.San Francisco Bay area:Within the next 30 years the probability is:72% that an earthquake measuring magnitude 6.751% that an earthquake measuring magnitude 720% that...

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What is the probability that an earthquake will occur in the Los Angeles Area? In the San Francisco Bay area?  

Los Angeles area:Within the next 30 years the probability is:60% that an earthquake measuring magnitude 6.746% that an earthquake measuring magnitude 731% that an earthquake measuring magnitude 7.5will occur in the Los Angeles region.San Francisco Bay area:Within the next 30 years the probability is:72% that an earthquake measuring magnitude 6.751% that an earthquake measuring magnitude 720% that...

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How do earthquakes affect buildings?

Ground shaking is the primary cause of earthquake damage to man-made structures. Many factors influence the strength of earthquake shaking at a site including the earthquake's magnitude, the site's proximity to the fault, the local geology, and the soil type. More than 250 structures throughout the United States have been outfitted with seismic sensors by the USGS National Strong Motion Project...

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How do earthquakes affect buildings?

Ground shaking is the primary cause of earthquake damage to man-made structures. Many factors influence the strength of earthquake shaking at a site including the earthquake's magnitude, the site's proximity to the fault, the local geology, and the soil type. More than 250 structures throughout the United States have been outfitted with seismic sensors by the USGS National Strong Motion Project...

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How do I decide whether or not to get earthquake insurance?

You should consider the following factors when deciding whether or not to get earthquake insurance:proximity to active earthquake faultsseismic history of the region (frequency of earthquakes)time since last earthquakebuilding construction (type of building and foundation)architectural layoutmaterials usedquality of workmanshipextent to which earthquake resistance was considered by the...

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How do I decide whether or not to get earthquake insurance?

You should consider the following factors when deciding whether or not to get earthquake insurance:proximity to active earthquake faultsseismic history of the region (frequency of earthquakes)time since last earthquakebuilding construction (type of building and foundation)architectural layoutmaterials usedquality of workmanshipextent to which earthquake resistance was considered by the...

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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?

The National Seismic Hazards Mapping project provides an online Web tool for determining the probability of a large earthquake within 50 kilometers (~31 miles) of a specific location in the United States over a certain time period. The calculation is based on the latest available information from seismic hazard data.However, asking if it's safe to travel somewhere because of recent earthquakes is...

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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?

The National Seismic Hazards Mapping project provides an online Web tool for determining the probability of a large earthquake within 50 kilometers (~31 miles) of a specific location in the United States over a certain time period. The calculation is based on the latest available information from seismic hazard data.However, asking if it's safe to travel somewhere because of recent earthquakes is...

Learn More