Due to a lapse in appropriations, the majority of USGS websites may not be up to date and may not reflect current conditions. Websites displaying real-time data, such as Earthquake and Water and information needed for public health and safety will be updated with limited support. Additionally, USGS will not be able to respond to inquiries until appropriations are enacted.  For more information, please see www.doi.gov/shutdown

Can "MegaQuakes" really happen? Like a magnitude 10 or larger?

No, earthquakes of magnitude 10 or larger cannot happen.  The magnitude of an earthquake is related to the length of the fault on which it occurs. That is, the longer the fault, the larger the earthquake. A fault is a break in the rocks that make up the Earth's crust, along which rocks on either side have moved past each other. No fault long enough to generate a magnitude 10 earthquake is known to exist, and if it did, it would extend around most of the planet.

The largest earthquake ever recorded was a magnitude 9.5 on May 22, 1960 in Chile on a fault that is almost 1,000 miles long… a “megaquake” in its own right.

Related Content

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Do solar flares or magnetic storms (space weather) cause earthquakes?

Solar flares and magnetic storms belong to a set of phenomena known collectively as "space weather". Technological systems and the activities of modern civilization can be affected by changing space-weather conditions. However, it has never been demonstrated that there is a causal relationship between space weather and earthquakes. Indeed, over...

Can some people sense that an earthquake is about to happen (earthquake sensitives)?

There is no scientific explanation for the symptoms some people claim to have preceding an earthquake, and more often than not there is no earthquake following the symptoms.

Can the ground open up during an earthquake?

Shallow crevasses can form during earthquake-induced landslides , lateral spreads , or from other types of ground failures , but faults do not open up during an earthquake. An earthquake occurs when two blocks of the earth’s crust slide past one another after having been stuck together in one place for a long time, because of fiction on the fault...

Will California eventually fall into the ocean?

No, California is not going to fall into the ocean. California is firmly planted on the top of the earth’s crust in a location where it spans two tectonic plates. The San Andreas Fault System, which crosses California from the Salton Sea in the south to Cape Mendocino in the north, is the boundary between the Pacific Plate (that includes the...

Is there earthquake weather?

In the 4th Century B.C., Aristotle proposed that earthquakes were caused by winds trapped in subterranean caves. Small tremors were thought to have been caused by air pushing on the cavern roofs, and large ones by the air breaking the surface. This theory lead to a belief in earthquake weather, that because a large amount of air was trapped...

Can animals predict earthquakes?

The earliest reference we have to unusual animal behavior prior to a significant earthquake is from Greece in 373 BC. Rats, weasels, snakes, and centipedes reportedly left their homes and headed for safety several days before a destructive earthquake. Anecdotal evidence abounds of animals, fish, birds, reptiles, and insects exhibiting strange...

Why are we having so many earthquakes? Has naturally occurring earthquake activity been increasing? Does this mean a big one is going to hit? OR We haven't had any earthquakes in a long time; does this mean that the pressure is building up for a big one?

A temporary increase or decrease in seismicity is part of the normal fluctuation of earthquake rates. Neither an increase or decrease worldwide is a positive indication that a large earthquake is imminent. The ComCat earthquake catalog contains an increasing number of earthquakes in recent years not because there are more earthquakes, but because...

Can you predict earthquakes?

No. Neither the USGS nor any other scientists have ever predicted a major earthquake. We do not know how, and we do not expect to know how any time in the foreseeable future. An earthquake prediction must define 3 elements : 1) the date and time, 2) the location, and 3) the magnitude. Yes, some people say they can predict earthquakes, but here are...

Are earthquakes associated with variations in the geomagnetic field?

Electromagnetic variations have been observed after earthquakes, but despite decades of work, there is no convincing evidence of electromagnetic precursors to earthquakes. It is worth acknowledging that geophysicists would actually love to demonstrate the reality of such precursors, especially if they could be used for reliably predicting...
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Date published: April 30, 2014

Can a Creeping Segment of the Alaska-Aleutian Subduction Zone Generate a Great Earthquake?

The coastal geology of Simeonof Island, the southeastern-most island in the Shumagin archipelago of the Aleutian Islands, suggests the region has not experienced a great megathrust earthquake in at least the past 3,400 years.

Date published: March 27, 2014

Prior Great Earthquakes Unveiled at the Western Edge of the 1964 Alaska Rupture

Ever since the great magnitude 9.2 earthquake shook Alaska 50 years ago today, scientists have suspected that the quake's rupture halted at the southwestern tip of Kodiak Island due to a natural barrier.

Date published: March 14, 2011

USGS Updates Magnitude of Japan’s 2011 Tohoku Earthquake to 9.0

The USGS has updated the magnitude of the March 11, 2011, Tohoku earthquake in northern Honshu, Japan, to 9.0 from the previous estimate of 8.9. Independently, Japanese seismologists have also updated their estimate of the earthquake’s magnitude to 9.0.

Date published: November 6, 2008

What Would a Great Earthquake do to the Buildings in Downtown Los Angeles?

A great earthquake along the southern San Andreas Fault could cause many tall buildings to collapse in Los Angeles, explains USGS earthquake expert Dr. Ken Hudnut in a new video interview.

Date published: February 10, 2005

2004 Deadliest in Nearly 500 Years for Earthquakes

According to the U.S. Geological Survey (USGS), 2004 was the deadliest year for earthquakes since the Renaissance Age, making it the second most fatal in recorded history, with more than 275,950 deaths reported from the magnitude 9.0 earthquake and subsequent tsunami that hit the Indian Ocean on Dec. 26. 

Date published: March 18, 1998

Mega Earthquake Not Likely For Southern California

Southern California is not likely to experience a "huge earthquake,"according to two scientists with the U.S. Geological Survey.

Date published: October 6, 1995


A magnitude 7.0 earthquake occurred on southern Sumatra, Indonesia, at 2:09 p.m. EDT (local time on Sumatra 1:09 a.m., Oct. 7). The epicenter was about 105 miles southeast of Panang or 290 miles southwest of Singapore.

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three dimensional conceptual drawing of a tectonic plate being pushed down under another plate.
March 6, 2017

Cascadia Subduction Zone

Block diagram illustrating an idealized geological setting offshore the state of Washington. As the subducting Juan De Fuca tectonic plate dives beneath North America, it can generate an earthquake, and trigger a tsunami.

February 24, 2014

PubTalk 2/2014 — 1964 Great Alaska Earthquake and Tsunami 50th Anniv.

By George Plafker, USGS Geologist Emeritus


  • March 27th, 1964, one of the most violent earthquakes of all time rocked southern Alaska.
  • More than 50,000 square miles of the state was tilted to new elevation, and the resulting property damage disrupted the state's economy.
  • Within 24 hours, a team of USGS geologists
April 2011 in waterfront area of Tohoku, Japan following the March 11, 2011 earthquake and tsunami.
April 11, 2011

Tohoku waterfront area, Japan

April 2011 in waterfront area of Tohoku, Japan following the March 11 2011 earthquake and tsunami.

April 29, 2010

PubTalk 4/2010 — Large, Destructive Earthquakes in Haiti and Chile

Lessons Learned for the San Francisco Bay Area

by USGS Geophysicists, Walter Mooney & Eric Geist 


  • Why was the January 2010 magnitude 7.0 earthquake in Haiti the 4th deadliest in history?
  • What have scientists discovered from seismology, satellite observations, and field investigations?
  • The Chilean
A home, severely damaged by the tsunami that hit Sumatra on December 26, 2004, sits atop debris.
January 21, 2005

Heavily damaged home in Banda Aceh, Sumatra from the 2004 tsunami

A severely damaged home, or a portion of one, sits atop debris in Banda Aceh on the island of Sumatra. Damage was caused by a massive, highly destructive tsunami, triggered by a magnitude 9.1 earthquake just offshore of Sumatra, on December 26, 2004.

Map showing the epicenter of the 11 March 2011 Tohoku earthquake off the coast of Japan and the Hawaiian Islands
November 30, 2000

Epicenter of 2011 Tohoku earthquake in relation to Hawaiian Islands

Map of the 11 March 2011 Tohoku earthquake epicenter in relation to the Northwestern and main Hawaiian Islands

1964 Alaska Earthquake damage

USGS Damage from the magnitude 9.2 earthquake in Alaska

Damage from the magnitude 9.2 earthquake in Alaska on March 27, 1964.

Attribution: Earthquake Hazards
Image: Destruction in Downtown Concepcion, Chile

Destruction in Downtown Concepcion, Chile

A masonry building in the downtown part of Concepcion, Chile partially collapsed as a result of the M 8.8 earthquake on Feb. 27, 2010. Most modern buildings in Concepcion were undamaged during the earthquake due to the city's adoption of adequate building standards. However, many masonry buildings such as this one were heavily damaged.