Earthquake Hazards Program

FAQ

Have questions? The answer is probably here!

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

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

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 (...

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. bar graph Bar graph showing the...

Where can I find a list of yearly estimated deaths from earthquakes around the world?

Our Earthquake Statistics website has annual totals for worldwide earthquakes and U.S. earthquakes from 1990 to the near-present. Estimated deaths from those earthquakes are listed at the bottom of the charts. The website also has M3+ earthquake counts by state beginning in 2010.

Which states have the smallest number of earthquakes? Is there any place in the world that doesn't have earthquakes?

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 has M3+ earthquake counts for each state beginning in 2010. Learn more: Earthquake Information by Region (scroll down for information by State/...

Where do earthquakes occur?

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...

Where can I find a list of the largest earthquakes in the United States? In the world?

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.

Where can I find a list of the largest earthquakes near my town?

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.

Which country has the most earthquakes?

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...

Which state has the most earthquakes that cause damage? Which state has the most earthquakes (not human-induced)?

California has more earthquakes that cause damage than any other state. Alaska and California have the most earthquakes (not human-induced). Learn more: Earthquake Information by Region (scroll down for individual states)

Where can I search an earthquake catalog for past events?

You might be able to find what you’re looking for using our collection of Earthquake Lists , so check that first. If that doesn’t work, use one of these Earthquake Catalog Search webpages: World-wide Earthquakes Catalog (M4.5+ worldwide, M2.5+ U.S.) Historic ANSS (Advanced National Seismic System) Composite Catalog (M4.5+ world-wide, all...

What is a fault and what are the different types?

A fault is a fracture or zone of fractures between two blocks of rock. Faults allow the blocks to move relative to each other. This movement may occur rapidly, in the form of an earthquake - or may occur slowly, in the form of creep . Faults may range in length from a few millimeters to thousands of kilometers. Most faults produce repeated...

What is the relationship between faults and earthquakes? What happens to a fault when an earthquake occurs?

Earthquakes occur on faults - strike-slip earthquakes occur on strike-slip faults, normal earthquakes occur on normal faults , and thrust earthquakes occur on thrust or reverse faults. When an earthquake occurs on one of these faults, the rock on one side of the fault slips with respect to the other. The fault surface can be vertical, horizontal,...

What is a "Quaternary" fault?

A Quaternary fault is one that has been recognized at the surface and that has moved in the past 1,600,000 years (1.6 million years). That places fault movement within the Quaternary Period , which covers the last 2.6 million years.

Where can I find a fault map of the United States? Is one available in GIS format?

An online map of United States Quaternary faults (faults that have been active in the last 1.6 million years) is available via the Quaternary Fault and Fold Database . There is an interactive map application to view the faults online and a separate database search function. KML (Google Earth-type) files and GIS shape files are also available for...

How do I find the nearest fault to a property or specific location?

If you are looking for faults in California use: How Close to a Fault Do You Live? (Bay Area Earthquake Alliance) For faults in California and the rest of the United States (as well as the latest earthquakes) use the Latest Earthquakes Map : click on the "gear" icon in the upper-right corner scroll down to Map Layers, and turn on U.S. Faults mouse...

How do I find fault or hazard maps for California?

An online map of faults that includes California is in the Faults section of the Earthquake Hazards Program website. Choose the Interactive Fault Map, or download KML files and GIS shapefiles from the links on the page. USGS seismic hazard maps, data, and tools for California and other parts of the United States are in the Hazards section of the...

Why are there no faults in the Great Valley of central California?

The Great Valley is a basin, initially forming ~100 million years ago as a low area between the subducting ocean plate on the west (diving down under the North American plate) and the volcanoes to the east (now the Sierra Nevada mountains). Since its formation, the Great Valley has continued to be low in elevation. Starting about 20 million years...

Why are there so many earthquakes and faults in the Western United States?

This region of the United States has been tectonically active since the supercontinent Pangea broke up roughly 200 million years ago, and in large part because it is close to the western boundary of the North American plate. Since the formation of the San Andreas Fault system 25-30 million years ago, the juxtaposition of the Pacific and North...