Enter the number of years of record and the number of events into the calculator to determine the average recurrence interval.
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Average Recurrence Interval Formula
The following formula is used to calculate the average recurrence interval for a given number of years of record and number of events.
ARI = Y / E
Variables:
- ARI is the average recurrence interval (years)
- Y is the number of years of record
- E is the number of events
To calculate the average recurrence interval, divide the number of years of record by the number of events.
What is an Average Recurrence Interval?
The average recurrence interval (ARI) is a statistical measure used in hydrology, seismology, and other fields to estimate the average time interval between events of a certain magnitude or intensity. It is commonly used to assess the risk of natural disasters such as floods, earthquakes, and storms. The ARI provides an indication of how often an event of a specific size can be expected to occur on average over a long period. For example, a 100-year flood has an ARI of 100 years, meaning that, on average, such a flood is expected to occur once every 100 years.
How to Calculate Average Recurrence Interval?
The following steps outline how to calculate the Average Recurrence Interval.
- First, determine the number of years of record (Y).
- Next, determine the number of events (E).
- Finally, calculate the Average Recurrence Interval using the formula ARI = Y / E.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Number of years of record (Y) = 50
Number of events (E) = 10