By George Plafker, USGS Geologist Emeritus
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.
Learn more:
Related
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. USGS scientists can only calculate the probability that a significant earthquake will occur ( shown on our hazard mapping) in a specific area within a certain number of years. An earthquake prediction must define 3 elements...
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 behavior anywhere from weeks to seconds before an...
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 nor 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 there are more seismic instruments and they are...
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 friction on the fault, while the rest of the crust away from the edges has...
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 Pacific Ocean) and North American Plate (that includes...
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 underground, the weather would be hot and calm before an...
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 the course of the Sun's 11-year variable cycle, the...
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 earthquakes! Learn more: USGS Geomagnetism Program
PubTalk 2/2014 — 1964 Great Alaska Earthquake and Tsunami 50th Anniv.
By George Plafker, USGS Geologist Emeritus
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
Lessons Learned for the San Francisco Bay Area
by USGS Geophysicists, Walter Mooney & Eric Geist
Can "Mega Quakes," which are earthquakes greater than a magnitude 10, really happen?
Listen to hear the answer.
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.
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.
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.
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.
Related
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. USGS scientists can only calculate the probability that a significant earthquake will occur ( shown on our hazard mapping) in a specific area within a certain number of years. An earthquake prediction must define 3 elements...
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 behavior anywhere from weeks to seconds before an...
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 nor 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 there are more seismic instruments and they are...
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 friction on the fault, while the rest of the crust away from the edges has...
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 Pacific Ocean) and North American Plate (that includes...
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 underground, the weather would be hot and calm before an...
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 the course of the Sun's 11-year variable cycle, the...
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 earthquakes! Learn more: USGS Geomagnetism Program
PubTalk 2/2014 — 1964 Great Alaska Earthquake and Tsunami 50th Anniv.
By George Plafker, USGS Geologist Emeritus
By George Plafker, USGS Geologist Emeritus
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
Lessons Learned for the San Francisco Bay Area
by USGS Geophysicists, Walter Mooney & Eric Geist
Can "Mega Quakes," which are earthquakes greater than a magnitude 10, really happen?
Listen to hear the answer.
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.
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.
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.
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.
Updated Date: July 22, 2024