Old Faithful

Old Faithful is perhaps the most studied and predicted geyser. Mathematicians, statisticians, and dedicated observers have analyzed it for many years. For example, a direct relationship exists between the duration of Old Faithful's eruption and the length of the following interval. Short eruptions (around 2 minutes) lead to short intervals (about 65 minutes), long eruptions (4 minutes or so) lead to long intervals (about 94 minutes). During a short eruption, less water and heat are discharged, thus, they rebuild again in a short time. Longer eruptions mean more water and heat are discharged and they require more time to rebuild. As of August 2002, the average interval was 94 minutes.