earthquake

American  

[urth-kweyk] / ˈɜrθˌkweɪk /

noun

• earthquakes
  plural

1. a series of vibrations induced in the earth's crust by the abrupt rupture and rebound of rocks in which elastic strain has been slowly accumulating.

   Synonyms:

   temblor, seism, shock, tremor, quake

2. something that is severely disruptive; upheaval.

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earthquake British  

/ ˈɜːθˌkweɪk /

noun

1. a sudden release of energy in the earth's crust or upper mantle, usually caused by movement along a fault plane or by volcanic activity and resulting in the generation of seismic waves which can be destructive

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earthquake Scientific  

/ ûrth′kwāk′ /

1. A sudden movement of the Earth's lithosphere (its crust and upper mantle). Earthquakes are caused by the release of built-up stress within rocks along geologic faults or by the movement of magma in volcanic areas. They are usually followed by aftershocks.

2. See Note at fault

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earthquake Cultural  

1. A tremor of the surface of the Earth, sometimes severe and devastating, which results from shock waves generated by the movement of rock masses deep within the Earth, particularly near boundaries of tectonic plates. (See fault, Richter scale, and seismology.)

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Closer Look

Fractures in Earth's crust, or lithosphere, where sections of rock have slipped past each other are called faults.Earthquakes are caused by the sudden release of accumulated strain along these faults, releasing energy in the form of low-frequency sound waves called seismic waves. Although thousands of earthquakes occur each year, most are too weak to be detected except by seismographs, instruments that detect and record vibrations and movements in the Earth. The point where the earthquake originates is the seismic focus, and directly above it on Earth's surface is the earthquake's epicenter. Three kinds of waves accompany earthquakes. Primary (P) waves have a push-pull type of vibration. Secondary (S) waves have a side-to-side type of vibration. Both P and S waves travel deep into Earth, reflecting off the surfaces of its various layers. S waves cannot travel through the liquid outer core. Surface (L) waves—named after the nineteenth-century British mathematician A.E.H. Love—travel along Earth's surface, causing most of the damage of an earthquake. The total amount of energy released by an earthquake is measured on the Richter scale. Each increase by 1 corresponds to a tenfold increase in strength. Earthquakes above 7 on the Richter scale are considered severe. The famous earthquake that flattened San Francisco in 1906 had a magnitude of 7.8.

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Earthquakes are particularly likely where such plates are sliding past each other, as in the San Andreas Fault.

Earthquakes cannot be accurately predicted, although the likelihood of a region's suffering an earthquake can be estimated.

Other Word Forms

Derived Forms

• preearthquake
  adjective

Inflected Forms

Nouns

• earthquakes
  plural

Etymology

Origin of earthquake

1300–50; Middle English erthequake ( see earth, quake), replacing Old English eorthdyne ( see din ¹)

Compare meaning

How does earthquake compare to similar and commonly confused words? Explore the most common comparisons:

• earthquake vs. aftershock
• temblor vs. earthquake

Explanation

If you're visiting your friend in California and her house starts to shake, you might be experiencing an earthquake, which is the shaking of the surface of the earth that happens when there's movement deep underground. Earthquake is one of those words that means exactly what it sounds like: the earth is quaking. Earthquakes happen along "fault lines," the places where the big plates of the earth meet and rub up against each other during volcanic activities. We also use earthquake metaphorically, to talk about something that causes a violent upheaval.

Example Sentences

See Examples For:

earthquake earthquakes

A joint statement issued by the two sides highlighted agreement on two topics after several days of discussion: reforming the judiciary, and seeking access to frozen funds to aid in earthquake recovery efforts.

From Barron's ● Aug. 13, 2026

I also found weird things like how many Atlantic hurricanes this year or if California will be hit by a magnitude 8 earthquake, which goes without saying but would be extremely bad.

From Salon ● Aug. 12, 2026

Colombia on Wednesday declared three days of mourning for victims of an earthquake that demolished buildings in the west of the country, killing more than 200 people.

From Barron's ● Aug. 12, 2026

The situation in Colombia is all-hands-on-deck and a litany of organizations worldwide are rallying together to get aid to earthquake victims.

From Los Angeles Times ● Aug. 11, 2026

After the earthquake, people all over Japan were in shock.

From "Meltdown" by Deirdre Langeland

For context, the recent Colombia and Venezuela earthquakes were both magnitude 7.4 and 7.5 respectively.

From Salon ● Aug. 12, 2026

The earthquake came only weeks after two massive earthquakes struck Venezuela, causing catastrophic destruction, particularly in urban areas in the northern part of the country near Caracas.

From Los Angeles Times ● Aug. 11, 2026

Official figures show that over 6,000 people died in the horrific earthquakes that struck Venezuela in June, but authorities are keeping their lips sealed about how many more are missing.

From Barron's ● Aug. 6, 2026

After earthquakes struck Emilia-Romagna in 2012, warehouses collapsed around hundreds of thousands of wheels of Parmigiano Reggiano, threatening the livelihoods of the cheesemakers who depended on them.

From Salon ● Aug. 6, 2026

They had hoped that more earthquakes, or perhaps a new growth on the bulge, would signal that the big one—the eruption they were all waiting for—was about to happen.

From "Mountain of Fire" by Rebecca E. F. Barone

Related Words

• shock
• temblor
• upheaval