foreshock


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Related to foreshock: tsunami, aftershock

foreshock

[′fȯr‚shäk]
(geophysics)
A tremor which precedes a larger earthquake or main shock.
References in periodicals archive ?
Instead, the cause of the electrons' acceleration was found to be within the foreshock region itself.
The fracture of individual asperities has similar characteristics to the sequence of natural earthquakes, consisting of foreshocks, mainshock, and aftershocks.
But today's rumble is but a mild foreshock of a tectonic demographic shift, a jolt that British Author Paul Wallace describes as an "agequake.
when that first tremor struck, a foreshock through which few in the city slept.
Figure 4 shows that the 1993 focal depth started with more than 10 km for foreshocks, no foreshock having less than 10 km depth.
5 foreshock could have weakened the buildings leading to major damage in consequence of the main shock (Cabanas-Rodriguez et al.
12am on April 18, 1906, the people of California felt the first foreshock of the massive San Francisco earthquake.
4 Banja Luka event of 27 October 1969, see Figures 3 and 5, preceded by a M4 foreshock of 26 October 1969.
On average, there is a 5 percent chance that a small quake such as Wednesday's was a foreshock, a precursor to a larger quake, Sieh said.
That was to be a foreshock of the largest earthquake to hit at 9:09pm local time which was at magnitude 5.