foreshock

American  

[fawr-shok, fohr-] / ˈfɔrˌʃɒk, ˈfoʊr- /

noun

Geology.

1. a relatively small earthquake that precedes a greater one by a few days or weeks and originates at or near the focus of the larger earthquake.

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foreshock British  

/ ˈfɔːˌʃɒk /

noun

1. a relatively small earthquake heralding the arrival of a much larger one. Some large earthquakes are preceded by a series of foreshocks Compare aftershock

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Etymology

Origin of foreshock

First recorded in 1900–05; fore- + shock ¹

Example Sentences

See Examples For:

foreshock

But she added that people were nervous about whether the quake "was a foreshock itself" and the "real one is on its way".

From BBC ● Apr. 23, 2025

In 1970, there was a magnitude 5.2 quake with a 4.0 foreshock close to the same location, she said.

From Seattle Times ● Jan. 5, 2024

The inability to recognize whether an earthquake in isolation is a foreshock is a big part of why useful prediction still eludes us.

From Scientific American ● Feb. 17, 2023

The downfall of the Fox host Bill O'Reilly in April 2017 turned out to have been just a foreshock of the changes to come.

From New York Times ● Oct. 23, 2018

Her early research on foreshock series — identifying certain smaller earthquakes as possible harbingers of a bigger one — enabled officials to start issuing earthquake advisories in California.

From Los Angeles Times ● Mar. 30, 2016