Old Faithful Geyser

Old Faithful is a cone geyser in Wyoming, in Yellowstone National Park in the United States. Old Faithful was named in 1870 during the Washburn-Langford-Doane Expedition and was the first geyser in the park to get a name.
Eruptions.
Eruptions can shoot 3,700 to 8,400 U.S. gallons (14–32 kL) of boiling water to a height of 106–184 feet (30–55 m) lasting from 1.5 to 5 minutes. The average height of an eruption is 145 feet (44 m).
Eruptions often occur about 90 minutes away from each other, but this difference in time can range from 45 to 125 minutes on occasion.
More than 137,000 eruptions have been recorded. Harry M. Woodward first described a mathematical relationship between the duration and intervals of the eruptions (1938). Old Faithful is not the highest or biggest geyser in the park; that title belongs to the less predictable Steamboat Geyser.
Increasing interval.
Over the years, the length of the difference of time has increased, which may be the result of earthquakes changing underground water levels. These disruptions have made the earlier mathematical relationship inaccurate, but have in fact made Old Faithful more predictable. With an error of 10 minutes, Old Faithful will erupt 65 minutes after an eruption lasting less than 2.5 minutes or 92 minutes after an eruption lasting more than 2.5 minutes. 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.
Measurement.
Between 1983 and 1994, four probes containing temperature and pressure measurement devices and video equipment were lowered into Old Faithful. The probes were lowered as deep as 72 feet (22 m). Temperature measurements of the water at this depth was 244 °F (118 °C), the same as was measured in 1942. The video probes were lowered to a maximum depth of 42 feet (13 m) to observe the conduit formation and the processes that took place in the conduit. Some of the processes observed include fog formation from the interaction of cool air from above mixing with heated air from below, the recharge processes of water entering into the conduit and expanding from below, and entry of superheated steam measuring as high as 265 °F (129 °C) into the conduit.