Recurrence interval

The average time span between two comparably large earthquakes on a particular seismogenic fault.

When at least two damaging earthquakes (the ones that would likely be well recorded also in historical seismicity sources) have been positively associated with a given active fault the time interval that separates them may provide tentative information concerning the periodicity of seismic events having similar magnitude causing damaging effects. Such interval – if reliably ascertained which requires broad and robust geological evidence – is likely to be far from ‘regular’ for a number of seismotectonic constraints. However it may yield some information concerning the broad time window after which the next comparable earthquake may be expected based on the time elapsed since the last recorded one.