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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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How will my house hold up in an earthquake? Can the USGS send someone out to evaluate my property?

Published maps will only provide generalized, uninterpreted information about specific areas. Every property consists of a unique combination of geologic and structural factors that must be considered to determine what might happen to a house during an earthquake. Therefore, an individual site study is necessary. Geologic factors include: type of underlying material, depth to bedrock, depth of...

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How will my house hold up in an earthquake? Can the USGS send someone out to evaluate my property?

Published maps will only provide generalized, uninterpreted information about specific areas. Every property consists of a unique combination of geologic and structural factors that must be considered to determine what might happen to a house during an earthquake. Therefore, an individual site study is necessary. Geologic factors include: type of underlying material, depth to bedrock, depth of...

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What are the earthquake hazards/risks where I live?

Determining your risk with regard to earthquakes, or more precisely shaking from earthquakes, isn't as simple as finding the nearest fault. The chances of experiencing shaking from an earthquake and/or having property damage is dependent on many different factors. The National Hazard Maps use all available data to estimate the chances of shaking (of different strengths and frequencies) across the...

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What are the earthquake hazards/risks where I live?

Determining your risk with regard to earthquakes, or more precisely shaking from earthquakes, isn't as simple as finding the nearest fault. The chances of experiencing shaking from an earthquake and/or having property damage is dependent on many different factors. The National Hazard Maps use all available data to estimate the chances of shaking (of different strengths and frequencies) across the...

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What is seismic hazard? What is a seismic hazard map? How are they made? How are they used? Why are there different maps, and which one should I use?

Seismic hazard is the hazard associated with potential earthquakes in a particular area, and a seismic hazard map shows the relative hazards in different areas. The maps are made by considering what we currently know about:Past faults and earthquakesThe behavior of seismic waves as they travel through different parts of the U.S. crustThe near-surface site conditions at specific locations of...

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What is seismic hazard? What is a seismic hazard map? How are they made? How are they used? Why are there different maps, and which one should I use?

Seismic hazard is the hazard associated with potential earthquakes in a particular area, and a seismic hazard map shows the relative hazards in different areas. The maps are made by considering what we currently know about:Past faults and earthquakesThe behavior of seismic waves as they travel through different parts of the U.S. crustThe near-surface site conditions at specific locations of...

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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...

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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...

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Oklahoma has had a surge of earthquakes since 2009. Are they due to fracking?

Beginning in 2009, Oklahoma experienced a surge in seismicity. This surge was so large that its rate of magnitude 3 and larger earthquakes exceeded California’s from 2014 through 2017.While these earthquakes have been induced by oil and gas related process, few of these earthquakes were induced by fracking. The largest earthquake known to be induced by hydraulic fracturing in Oklahoma was a M3.6...

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Oklahoma has had a surge of earthquakes since 2009. Are they due to fracking?

Beginning in 2009, Oklahoma experienced a surge in seismicity. This surge was so large that its rate of magnitude 3 and larger earthquakes exceeded California’s from 2014 through 2017.While these earthquakes have been induced by oil and gas related process, few of these earthquakes were induced by fracking. The largest earthquake known to be induced by hydraulic fracturing in Oklahoma was a M3.6...

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Are earthquakes induced by fluid-injection activities always located close to the point of injection?

No. Given enough time, the pressure increase created by injection can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes can occur 10 or more miles from injection wells. Induced earthquakes can also occur a few miles below injection wells.Learn more: USGS Induced Earthquakes

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Are earthquakes induced by fluid-injection activities always located close to the point of injection?

No. Given enough time, the pressure increase created by injection can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes can occur 10 or more miles from injection wells. Induced earthquakes can also occur a few miles below injection wells.Learn more: USGS Induced Earthquakes

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Does the production of oil and gas from shales cause earthquakes? If so, how are the earthquakes related to these operations?

To produce oil and gas from shale formations, it is necessary to increase the interconnectedness of the pore space (permeability) of the shale so that the gas can flow through the rock mass and be extracted through production wells. This is usually done by hydraulic fracturing ("fracking"). Fracking intentionally causes small earthquakes (magnitudes smaller than 1) to enhance permeability, but it...

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Does the production of oil and gas from shales cause earthquakes? If so, how are the earthquakes related to these operations?

To produce oil and gas from shale formations, it is necessary to increase the interconnectedness of the pore space (permeability) of the shale so that the gas can flow through the rock mass and be extracted through production wells. This is usually done by hydraulic fracturing ("fracking"). Fracking intentionally causes small earthquakes (magnitudes smaller than 1) to enhance permeability, but it...

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How large are the earthquakes induced by fluid injection?

The largest earthquake induced by fluid injection that has been documented in the scientific literature was a magnitude 5.8 earthquake on September 23, 2016 in central Oklahoma. Four magnitude 5+ earthquakes have occurred in Oklahoma, three of which occurred in 2016. In 2011, a magnitude 5.3 earthquake was induced by fluid injection in the Raton Basin, Colorado. Earthquakes with magnitudes between...

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How large are the earthquakes induced by fluid injection?

The largest earthquake induced by fluid injection that has been documented in the scientific literature was a magnitude 5.8 earthquake on September 23, 2016 in central Oklahoma. Four magnitude 5+ earthquakes have occurred in Oklahoma, three of which occurred in 2016. In 2011, a magnitude 5.3 earthquake was induced by fluid injection in the Raton Basin, Colorado. Earthquakes with magnitudes between...

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Is there any possibility that a wastewater injection activity could interact with a nearby fault to trigger a major earthquake that causes extensive damage over a broad region?

So far, there is no documented example linking injection operations to triggering of major earthquakes. However, we cannot eliminate this possibility. Other human activities--for example oil production in Uzbekistan--have induced M7+ earthquakes.Learn more: USGS Induced Earthquakes

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Is there any possibility that a wastewater injection activity could interact with a nearby fault to trigger a major earthquake that causes extensive damage over a broad region?

So far, there is no documented example linking injection operations to triggering of major earthquakes. However, we cannot eliminate this possibility. Other human activities--for example oil production in Uzbekistan--have induced M7+ earthquakes.Learn more: USGS Induced Earthquakes

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How does the injection of fluid at depth cause earthquakes?

The fluid that is injected at depth is sometimes hydraulically connected to faults. When this happens, fluid pressures increase within the fault, counteracting the frictional forces on faults. This makes earthquakes more likely to occur on them. An analog to this system is an air hockey table. When an air hockey table is off, the puck does not move readily, but when the table is on, the puck...

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How does the injection of fluid at depth cause earthquakes?

The fluid that is injected at depth is sometimes hydraulically connected to faults. When this happens, fluid pressures increase within the fault, counteracting the frictional forces on faults. This makes earthquakes more likely to occur on them. An analog to this system is an air hockey table. When an air hockey table is off, the puck does not move readily, but when the table is on, the puck...

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Is it possible to anticipate whether a planned wastewater disposal activity will trigger earthquakes that are large enough to be of concern?

Currently, there are no methods available to do this in a definitive sense. We have developed methods that use injection information to help us determine whether injection activities might cause induced earthquakes and rule out other injection activities that are unlikely to induce earthquakes, but we cannot say either with certainty.There are a number of conditions that increase the likelihood of...

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Is it possible to anticipate whether a planned wastewater disposal activity will trigger earthquakes that are large enough to be of concern?

Currently, there are no methods available to do this in a definitive sense. We have developed methods that use injection information to help us determine whether injection activities might cause induced earthquakes and rule out other injection activities that are unlikely to induce earthquakes, but we cannot say either with certainty.There are a number of conditions that increase the likelihood of...

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Do all wastewater disposal wells induce earthquakes?

No. Of more than 150,000 Class II injection wells in the United States, roughly 40,000 are waste fluid disposal wells for oil and gas operations. Only a small fraction of these disposal wells have induced earthquakes that are large enough to be of concern to the public.Learn more:USGS Induced EarthquakesEPA's Underground Injection Control (UIC) program

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Do all wastewater disposal wells induce earthquakes?

No. Of more than 150,000 Class II injection wells in the United States, roughly 40,000 are waste fluid disposal wells for oil and gas operations. Only a small fraction of these disposal wells have induced earthquakes that are large enough to be of concern to the public.Learn more:USGS Induced EarthquakesEPA's Underground Injection Control (UIC) program

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