foreshock

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Related to foreshocks: Seismic waves, Aftershocks

foreshock

[′fȯr‚shäk]
(geophysics)
A tremor which precedes a larger earthquake or main shock.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
They might help bridge the gap between observations of real fault systems and laboratory earthquake experiments where foreshock occurrence is commonly observed.
"Even if a foreshock occurs, there is no means to identify whether it is actually a aACAyforeshock' and that a major quake will follow."
The index numbers to the exponent n do not differ largely in agreement to the near steady percent of each type in comparison with previous result of 0.5 for rock experiment and 1.7 for foreshocks.
The conviction, which the American Association for the Advancement of Science called unfair and naive, was handed down due to the fact that the Major Risks Committee met days before the quake after small tremors were felt and, in the opinion of the court, were too confident in dismissing the foreshocks as signs of a looming, deadly seismic event.
An intense educational campaign kept the population on alert, so when some experts issued a warning after several foreshocks, a combination of organized and spontaneous activity drove people out of their houses.
They are now studying how foreshocks and aftershocks play a role in predicting events and dealing with the aftermath.
before the main shock are called foreshocks, and those after are called
The similarity of orientation and source mechanism solutions of the Kaghan Valley earthquakes with that of the Muzaffarabad earthquake of 2005, indicate that they were, most probably, the foreshocks of the Muzaffarabad earthquake.
11, Hurricane Katrina, the financial meltdown, and the current economic recession are the foreshocks revealing a deep crisis in our nation.
"In contrast to what takes place in natural seismic activity, the most violent shocks are most often produced after numerous foreshocks. The frequency of these shocks increases progressively during a more or less long period.