What are earthquake lights?

Phenomena such as sheet lightning, balls of light, streamers, and steady glows, reported in association with earthquakes are called earthquake lights (EQL).  Geophysicists differ on the extent to which they think that individual reports of unusual lighting near the time and epicenter of an earthquake actually represent EQL:  some doubt that any of the reports constitute solid evidence for EQL, whereas others think that at least some reports plausibly correspond to EQL.  Physics-based hypotheses have been proposed to explain specific classes of EQL reports, such as those in the immediate vicinity of the causative fault at the time of a major earthquake.  On the other hand, some reports of EQL have turned out to be associated with electricity arcing from the power lines shaking.

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How does the USGS tell the difference between an earthquake and a sonic boom?

Steps to identification of a sonic boom: The USGS sees either nothing on our seismic records or a fairly short high-frequency signal that doesn't look like an earthquake. On rare occasions, we see the event on multiple stations, and the time difference between stations matches the speed of sound in air, which is slower than the speed of seismic...

Can you feel an earthquake if you're in a cave? Is it safer to be in a cave during an earthquake?

There is nothing different about a cave that would make it immune to the shaking from an earthquake. Just as there are safer and less safer places to be on the surface of the earth during an earthquake, there are also various characteristics inside caves that make some cave locations safer or less safe than others. First of all, whether or not you...

What is liquefaction?

Liquefaction takes place when loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking. Liquefaction occurring beneath buildings and other structures can cause major damage during earthquakes. For example, the 1964 Niigata earthquake caused widespread liquefaction in Niigata,...

Where can I find photographs of earthquake damage?

Two sources for photographs that show earthquake damage are: Earthquake Hazards Program - Earthquake Photo Collections U.S. Geological Survey Photographic Library (see 'earthquakes' in the categories left column)

Why do earthquakes in other countries seem to cause more damage and casualties than earthquakes in the U.S.?

There is more damage and more deaths from earthquakes in other parts of the world primarily because of buildings which are poorly designed and constructed for earthquake regions, and population density.

How can an earthquake affect groundwater or changes in wells?

Groundwater levels in wells may oscillate up and down while seismic waves pass, and in some cases, the water level may remain higher or lower for a period of time after the seismic wavetrain has ended.

What are those booms I sometimes hear before or during an earthquake?

"Booms" have been reported for a long time, and they tend to occur more in the Northeastern US and along the East Coast. Of course, most "booms" that people hear or experience are actually some type of cultural noise, such as some type of explosion, a large vehicle going by, or sometimes a sonic boom, but there have been many reports of "booms"...

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 also depends on other variables, such as the 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.

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...
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Date published: April 25, 2005

Are You Safe When A Natural Hazard Strikes? Learn How Science Can Help Reduce the Risk of Loss of Life and Property When Natural Hazards Occur


Reston, VA – More Americans are at risk from being severely impacted by natural hazards now than any other time in our nation’s history.

Date published: October 5, 1999

"The Next Big Earthquake" — Still Helpful and Still Available; From USGS

With a press run of more than three million copies, "The Next Big Earthquake In The Bay Area May Come Sooner Than You Think-- Are You Prepared?" is the most widely distributed publication ever prepared by the U.S. Geological Survey. Nine years after it’s publication, it is still available from the USGS, and still helpful as a preparedness guide for Bay Area residents.

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Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake in 2016
February 24, 2017

Damage in Cushing, Oklahoma from the Magnitude 5.0 Earthquake in 2016

Damage to buildings in Cushing, Oklahoma from the magnitude 5.0 earthquake on November 6, 2016. Unreinforced brick and stone masonry buildings and facades are vulnerable to strong shaking. Photograph credit: Dolan Paris, USGS

January 31, 2017


The National Aeronautics and Space Administration's VISIONS—VISualizing Ion Outflow via Neutral atom imaging during a Substorm—sounding rocket mission is studying what makes auroras and how they affect Earth’s atmosphere. The VISIONS rocket was launched at night in Poker Flats, Alaska, in February 2013. Credit: Joshua Strang, U.S. Air Force

Image shows a road split due to earthquake damage
November 30, 2000

1964 Alaskan Earthquake Damage

Damage from the 1964 Alaskan Earthquake. Credit: USGS

Image: Northridge, CA Earthquake Damage
January 1, 1994

Northridge, CA Earthquake Damage

Collection of USGS still images taken after the January 17, 1994 Northridge earthquake highlighting the damage to buildings and infrastructure.

Attribution: Natural Hazards
Image: Mw6.6 Lushan China Earthquake, April 20 2013

Mw6.6 Lushan China Earthquake, April 20 2013

Damage to a village house. Longxingcun.