# Online exposure age calculator statistics

Here is the latest on usage of the online exposure age calculators. This covers the period from their inception in 2006 until November 6, 2013.

1. Monthly number of calculation requests from 2006-2013. A calculation request is a request to compute an exposure age or an erosion rate from one sample. If you enter the same sample twice on separate occasions, that generates two calculation requests. The example samples that are invoked from the dropdown menus on the entry pages do not generate a record of a calculation request. Overall, there has been a steady increase with what appears to be a seasonal cycle.

2. Let’s investigate the seasonal cycle a bit more. If we bin by calendar months in all years, we see steady usage in the first half of the year, a summer lull, an October-November peak that is presumably related to AGU and GSA deadlines, and then a quiet December.

3. Annual usage. A bit of a lull in 2009-10 followed by strong performance in the last two years. Add in December of 2013 and it looks like another record year. This also shows the breakdown between exposure age calculations (black) and erosion rate calculations (red). Geomorphologists interested in erosion rates are either fewer in number or more easily satisfied by the initial result of a calculation. Geochronologists are either more numerous or more likely to repeat calculations. However, erosion rate calculations are increasing in popularity.

4. And the summary statistics:

As of November 6, 2013, the online exposure age and erosion rate calculators have handled 429,616 calculation requests, for an average of 5,354 per month over the period of operation. This breaks down to 180/day.

The biggest day: July 24, 2013, on which 3,725 calculation requests were served. Nearly all of these originated from a single IP address.

5. More information.

If you want a closer look at the web server statistics (computed by Webalizer, so oriented toward page views rather than calculation requests), they are here.