HOW DO CHANGES IN PRECIPITATION AFFECT HYDROTHERMAL AND VOLCANIC ACTIVITY AT YELLOWSTONE CALDERA?

Yellowstone Caldera (YC), USA, is an area of geothermal activity that is fueled by a volcanic hotspot. The goal of this study is to analyze the impacts climate change, specifically precipitation change, has on the hydrothermal system. I do this in three ways: (1) understanding the relationship between precipitation and geyser eruptions, (2) comparison with other volcanic systems, and (3) thermal modelling of the YC.

My initial study of the area shows a correlation between rainfall and geyser eruptions. Precipitation data collected from NOAA shows the average precipitation each year has increased by 1.41 inches over the last century. Geyser eruption data, i.e. eruption events, were collected from geysertimes.org, a publicly sourced database of geyser eruptions. Using these data I identified geyser swarms, i.e. increased frequency of geyser eruptions for a given geyser over a short period of time. In comparing the geyser data to precipitation data in Yellowstone County, there are trends in geyser activity with increasing in precipitation in some geysers. For example, Steamboat and Constant geysers showed signs of geyser swarms, following wetter periods. Contrasting, Echinus geyser shows more constant activity and little or no correlation to long term rainfall patterns. I am continuing this study with other geysers in the Norris Geyser Basin.

I also compared YC to two other calderas, Valles Caldera (VC) in New Mexico, and Long Valley Caldera (LVC) in California. Both VC and LVC have had more active geothermal activity in the past. Both calderas, also once had lakes within the calderas which dried due to regional climate change, altering the overall hydrothermal system. Presently, NOAA shows the yearly average precipitation near VC has decreased by 0.79 inches over the last century and the region of LVC has seen very little change. This presents a sharp contrast to YC which is generally trending toward increasing precipitation. Using a two-dimensional thermal cooling model, I am modelling these volcanic–hydrothermal systems to better assess the relationship between geyser activity and thermal cooling of the magma chamber. I propose that VC and LVC can be blueprints for future activity at YC.