Yellowstone Caldera: The Slumbering Beast
The misunderstood story of what is happening below Yellowstone National Park's surface.
Ash deposits of some of North America's largest volcanic eruptions. Provided by the USGS.
To begin to understand what is happening now and what will happen in the future, we must first look to the past.
This map shows where the ash deposits of Yellowstone's previous eruptions reached. Seeing how far-reaching these deposits are has spurred scientists to understand the volcano before it erupts again.
Yellowstone National Park and Geothermal Features - Map created by Jessica Perron. This shows the major geothermal areas as well as the smaller geothermal areas within Yellowstone National Park.
Geothermal Hotspots are one of the few indicators of what is truly going on beneath the surface. The closeness of the magma chamber that fuels the Yellowstone Volcano heats the surrounding rock, in turn, it heats the water that gets close enough. The water boils and will sometimes reach a flashpoint (suddenly turns to gas) and creates the spectacular view of the geysers we all know.
Old Faithful Geyser eruption Yellowstone NP - Posted by Rick Beach
Geyser Basin in Yellowstone National Park - Taken in January 2019 by Jessica Perron
Geysers aren't the only occurrence. Mud pots, hot springs, fumaroles, and many other types of geothermal activity are influenced by the heated rocks. In most of these hot spots, there is monitoring equipment that takes data such as temperatures, gas composition, and activity levels.
Did you know that the activity level of a spring or geyser can change drastically with one earthquake? Several geysers have turned to quiet pools and pools have transformed into roiling, roaring water with a single earthquake event.
Prismatic Pool in Yellowstone National Park - Taken in May 2019 by Jessica Perron
Map created by Jessica Perron. This map shows the geothermal areas partnered with the fault lines that exist in Yellowstone National Park. It is along these faults where the earthquakes occur in the park.
Another key sign that beneath the Yellowstone National Park lies a supervolcano is the number of earthquakes that happen per year there and the frequency of earthquake swarms.
Image provided by the USGS. A map indicating the earthquake hazard risk for the united states.
In Yellowstone National Park, there is an average of 1,500 to 2,000 earthquakes per year! It is among the most high-risk places in the country for earthquake activity and severity. However, many of these earthquakes go undetected by humans (human detectability stops at about 3.0 magnitude earthquakes) and can only be picked up by machines.
Below is a record of the earthquake swarms that took place between 1950 to 2017. Each dot can represent anywhere between 5 to 100 earthquakes.
Yellowstone National Park and Earthquake Swarms - Map created by Jessica Perron. This is a map that locks the general locations for earthquake swarms between the years of 1950 to 2017.
Map created by Jessica Perron. This is a map that compares the earthquake swarms that have occurred between 1950 and 2017.
This map is a comparison map to show where the known faults are and where many of the earthquake swarms have occurred. This can give an idea of the activity levels of some of the faults and where maybe there could either be new faults or something else that we need to turn our attention to.
Earthquake swarms are an indicator to the activity level of the volcano that slumbers beneath. These earthquakes could point to the volcano getting ready to erupt or if it is beginning to move (which it has due to the movement of the North American tectonic plate).
Map created by Jessica Perron. This map shows many of the geothermal features, campsites, and trails of the Yellowstone National Park.
This map shows the locations for most of the campsites and hiking trails within the Yellowstone National Park. Many of these are near the major faults in the park, but since so many earthquakes occur on these faults, there is little pressure being built up. The more pressure build-up, the stronger the earthquakes, and the less time pressure has to build up, the weaker the earthquakes will be.
However, that doesn't make it impossible for strong earthquakes to occur, which is why the monitoring process is always underway in Yellowstone National Park.
Conclusion
There is so much to be discovered about the volcano that slumbers beneath Yellowstone and other volcanoes like it. Understanding is the key to being able to help people in the event of a disaster. The discovery process will continue to grow and maybe one day we will fully understand the processes that are lurking beneath our feet.
