Frequently Asked Questions

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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Image: Bakken Oil Well
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 (...
Research has identified 17 areas in the central and eastern United States with increased rates of induced seismicity.
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
cartoon for fluid injection and withdrawal
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
Epicenter of the Oklahoma 5.6 earthquake on Sept 3, 2016
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...
Oil production and wastewater disposal
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...
Image: Wastewater Disposal Facility in Colorado
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...
Oil and Gas Wastewater Disposal Facility in West Virginia
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 Earthquakes EPA's Underground Injection Control (UIC...
Earthquake Catalog Map Results Example
You may be able to find what you’re looking for using our collection of Earthquake Lists, so check that first. If that doesn’t work, you can use one of these Earthquake Catalog Search webpages: Search the World-wide Earthquakes Catalog (M4.5+ worldwide, M2.5+ U.S.)Search the Historic ANSS (Advanced National Seismic System) Composite Catalog (M4.5...
Image: Northridge, CA Earthquake Damage
California has the most damaging earthquakes, and Alaska and California have the most natural (non-manmade) earthquakes. Find information about earthquakes in each state on our Earthquake Information by Region website (scroll down).
Image: Damage from 2008 Great Sichuan Earthquake in China
The answer to this question is not as straightforward as it may seem. In order to most accurately answer it, we will rephrase the question four different ways: For which country do we locate the most earthquakes? Japan. The whole country is in a very active seismic area, and they have the densest seismic network in the world, so they are able to...
Damage from South Napa Earthquake
Use our online earthquake catalog to search for past earthquakes in your region. Define your search area by drawing a rectangle on a map or by inputting data for a rectangle or circle. Go to our Earthquake Information by Region website and scroll down to find information about earthquakes in each state.
Devastation of 1906 San Francisco Earthquake
The USGS Earthquake Lists, Maps, and Statistics website has statistics about earthquakes in the United States and the world, including a list of the world's 20 largest recorded earthquakes.