an increase in small earthquakes before a main earthquake
a small earthquake occurring before a main earthquake
A small earthquake that may precede a larger earthquake or main shock and that originates at or near the focus of the larger event.
ground shaking that occurs before the main shock of an earthquake.
An earthquake that is smaller than, and precedes, a "mainshock". Foreshocks tend to occur in the same area as the mainshock. Foreshocks have not been observed before damaging earthquakes in British Columbia.
A small tremor that commonly precedes a larger earthquake or main shock by seconds to weeks and that originates at or near the focus of the larger earthquake.
a small tremor before a major earthquake
Any earthquake which is followed, within a short time span, by a larger earthquake in the exact same location can be labelled a "foreshock". (In the case of an earthquake swarm, this terminology is not generally applied.)
A foreshock is a smaller earthquake preceding a much larger earthquake. Many scientists hope to use foreshocks to predict upcoming earthquakes.
