General Information
Old Faithful is a cone geyser in Yellowstone National Park in Wyoming. It was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to be named. It is a highly predictable geothermal feature and has erupted every 44 minutes to two hours since 2000. The geyser and the nearby Old Faithful Inn are part of the Old Faithful Historic District.
In the afternoon of September 18, 1870, the members of the Washburn-Langford-Doane Expedition traveled down the Firehole River from the Kepler Cascades and entered the Upper Geyser Basin. The first geyser that they saw was Old Faithful.
More than 1,000,000 eruptions have been recorded. Harry Woodward first described a mathematical relationship between the duration and intervals of the eruptions in 1938. Old Faithful is not the tallest or largest geyser in the park; those titles belong to the less predictable Steamboat Geyser. The reliability of Old Faithful can be attributed to the fact that it is not connected to any other thermal features of the Upper Geyser Basin.
Eruptions can shoot 3,700 to 8,400 US gallons (14,000 to 32,000 L) of boiling water to a height of 106 to 185 feet (32 to 56 m) lasting from 1+1/2 to 5 minutes. The average height of an eruption is 145 feet (44 m). Intervals between eruptions can range from 60 to 110 minutes, averaging 66.5 minutes in 1939, slowly increasing to an average of 90 minutes apart today, which may be the result of earthquakes affecting subterranean water levels. The disruptions have made earlier mathematical relationships inaccurate, but have actually made Old Faithful more predictable in terms of its next eruption. After the Borah Peak earthquake in central Idaho in October 1983, the eruption intervals of Old Faithful were noticeably lengthened.
This article uses material from the Wikipedia article "Old Faithful", which is released under the Creative Commons Attribution-Share-Alike License 3.0
