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 magnitude 7.8 earthquake that struck the area in 2015 and triggered a rock-ice avalanche, could have also weakened the underlying rock mass, according to the study.

From BBC ● Sep. 17, 2026

Residents said that many of the findings reflect their experiences — and validate their fears as they work to rebuild in a region infamous for its wildfire, earthquake and flood risks.

From Los Angeles Times ● Sep. 15, 2026

Only the biggest one or two are going to survive the coming technological earthquake and mass corporate consolidation.

From The Wall Street Journal ● Sep. 15, 2026

Local landslides are particularly challenging because their effects can develop quickly and may not be preceded by a felt earthquake.

From Science Daily ● Sep. 10, 2026

Grandma had been astonished when none of the Palmers knew anything about an earthquake.

From "Earthquake Terror" by Peg Kehret

The twin earthquakes on June 24, which killed 6,500 people in Venezuela, were an inflection point for her.

From The Wall Street Journal ● Sep. 19, 2026

A series of small earthquakes gently shook the communities of Lennox and Westmont from Friday night into Saturday, causing concern among residents.

From Los Angeles Times ● Sep. 13, 2026

But information posted by the organization says micro-quakes aren’t a predictor of larger earthquakes.

From Los Angeles Times ● Sep. 13, 2026

Working within the international system coordinated by UNESCO, it monitors earthquakes that could generate tsunamis and sends initial messages to French emergency authorities and other warning centers.

From Science Daily ● Sep. 10, 2026

She believed that just as the power of her mind could move the saltcellar on the table, she could also produce deaths, earthquakes, and other, even worse catastrophes.

From "The House of the Spirits: A Novel" by Isabel Allende

Related Words

• shock
• temblor
• upheaval