Chemical geothermometer temperatures for Porkchop Geyser, Yellowstone National Park, prior to its 1989 explosion

Fluid chemical geothermometer temperatures for Porkchop Geyser in Norris Geyser Basin, Yellowstone National Park, showing an increase of 40–60 °C (72–108 °F) for deep subsurface fluid temperatures near the time of the September 1989 Porkchop hydrothermal explosion.  Note the significant scatter and variations of estimates using the conventional geothermometers.  New geothermometers developed based on principles of thermodynamics may provide more precise data in the future.  Data from Fournier and others, 1991 (https://doi.org/10.1130/0016-7606(1991)103<1114:CLTARS>2.3.CO;2), and diagram from Morgan and others, 2009 (https://doi.org/10.1130/2009.2459(01)).