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

But conventionally, only half of earthquakes have an easily detectable foreshock, while the other half do not.

From Los Angeles Times

Indeed, only about 5% of earthquakes are "foreshocks", said Bradley and Hubbard.

From BBC

There had been foreshocks, smaller earthquakes that shook the countryside for days before the main event, but there’s nothing unusual about earthquakes in Japan.

From Literature

This may have been a foreshock - an early release of energy - but it is not a predictor of exact timing of a future earthquake, explained Prof McNeill.

From BBC

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