Return period

A return period, also known as a recurrence interval or repeat interval, is an average time or an estimated average time between events such as earthquakes, floods,^[1] landslides,^[2] or river discharge flows to occur.

It is a statistical measurement typically based on historic data over an extended period, and is used usually for risk analysis. Examples include deciding whether a project should be allowed to go forward in a zone of a certain risk or designing structures to withstand events with a certain return period. The following analysis assumes that the probability of the event occurring does not vary over time and is independent of past events.

^ ASCE, Task Committee on Hydrology Handbook of Management Group D of (1996). Hydrology Handbook | Books. doi:10.1061/9780784401385. ISBN 978-0-7844-0138-5.
^ Peres, D. J.; Cancelliere, A. (2016-10-01). "Estimating return period of landslide triggering by Monte Carlo simulation". Journal of Hydrology. Flash floods, hydro-geomorphic response and risk management. 541: 256–271. Bibcode:2016JHyd..541..256P. doi:10.1016/j.jhydrol.2016.03.036.

[1] ASCE, Task Committee on Hydrology Handbook of Management Group D of (1996). Hydrology Handbook | Books. doi:10.1061/9780784401385. ISBN 978-0-7844-0138-5.

[2] Peres, D. J.; Cancelliere, A. (2016-10-01). "Estimating return period of landslide triggering by Monte Carlo simulation". Journal of Hydrology. Flash floods, hydro-geomorphic response and risk management. 541: 256–271. Bibcode:2016JHyd..541..256P. doi:10.1016/j.jhydrol.2016.03.036.

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