mainshock

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English - English
The maximum shock in an earthquake event. Sometimes preceded by foreshocks and followed by aftershocks which are of lesser intensity
The largest in a series of earthquakes occurring closely in time and space The mainshock may be preceded by foreshocks or followed by aftershocks
The largest earthquake in any series of earthquakes; to be definitively called a "mainshock", it should generally be at least half a magnitude unit larger than the next largest quake in the series Otherwise, the series of quakes may more accurately fit the definition of a swarm
The largest earthquake in a sequence, sometimes preceded by one or more foreshocks, and almost always followed by many aftershocks