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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Simulation of fluid pressure increases from injection into a reservoir over time.
No. Given enough time, the pressure increase created by injection can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes commonly occur several kilometers below the injection point. 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 the September 23, 2016 earthquake in central Oklahoma. It had a magnitude of 5.8. 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...
Oil production and wastewater disposal
Earth's crust is pervasively fractured at depth by faults. These faults can sustain high stresses without slipping because natural "tectonic" stress and the weight of the overlying rock pushes the opposing fault blocks together, increasing the frictional resistance to fault slip. The injected wastewater counteracts the frictional forces on faults...
Image: Wastewater Disposal Facility in Colorado
Currently, there are no methods available to do this. Three conditions must be met for injection to induce an earthquake:  Presence of a fault Stresses acting on the fault favorable to slip A pathway for the pressure increase from injection to interact with the fault.  Evidence from some case histories suggests that the magnitude of the largest...
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.
Pacific Plate boundaries and relative motion
Earthquakes can strike any location at any time, but history shows they occur in the same general patterns year after year, principally in three large zones of the earth: The world's greatest earthquake belt, the circum-Pacific seismic belt, is found along the rim of the Pacific Ocean, where about 81 percent of our planet's largest earthquakes...
Sunset over South Florida WARC
Florida and North Dakota are the states with the fewest earthquakes. Antarctica has the least earthquakes of any continent, but small earthquakes can occur anywhere in the World. Our Earthquake Statistics website has M3+ earthquake counts for each state beginning in 2010. Learn more: Earthquake Information by Region (scroll down for information by...