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.

---

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

---

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

---

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.)

---

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.

Discover More

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

The coordinated intervention was the first since 2011, when both countries took action together to weaken the yen after the devastating earthquake and tsunami that hit eastern Japan.

From BBC ● Sep. 18, 2026

Chief Facilities Executive Krisztina Tokes could offer no such assurance, advising the board that state earthquake mitigation funds are underfunded and oversubscribed.

From Los Angeles Times ● Sep. 16, 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

During an earthquake, people should first protect themselves from the shaking, then move to safety as soon as they can.

From Science Daily ● Sep. 10, 2026

What if the earthquake caused the redwood to move again?

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

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

From Los Angeles Times ● Sep. 13, 2026

The Compton area experienced two earthquakes in a matter of three days in 2019.

From Los Angeles Times ● Sep. 6, 2026

Northern Oregon experiences relatively little seismic activity compared with western Washington and northern California, leaving researchers with fewer earthquakes to use when studying the buried slab and the way seismic waves move through the region.

From Science Daily ● Aug. 30, 2026

Opposing them were the Plutonists, who noted that volcanoes and earthquakes, among other enlivening agents, continually changed the face of the planet but clearly owed nothing to wayward seas.

From "A Short History of Nearly Everything" by Bill Bryson

Related Words

• shock
• temblor
• upheaval