JACKSON, Wyo. — According to the Yellowstone Volcano Observatory’s (YVO) most recent Caldera Chronicles, the Yellowstone Seismic Network (YSN) records more than just earthquakes.
YVO writes that the Yellowstone region experiences an average of 1,500 to 2,500 earthquakes per year, one of the most-seismically active areas in the western U.S. While the YSN is designed to record these earthquakes and send data back to the University of Utah in real time for analysis, a number of other things that cause the ground to shake is recorded by seismic stations in and around the area.
The most common causes include humans and the vehicles they drive. YVO confirms that seismic stations are located far away from roads to avoid these signals, but there are some that are close enough to record every car, truck, bus or RV that drives by.
“A seismic station that is located near the Madison-West Entrance Road…is notorious for recording road noise,” YVO writes. “In addition, a seismic station that is located in the Norris Geyser Basin Museum…records the thousands of visitors that walk by it every day during the summer. Most of the time, it is easy to differentiate these signals from those of real earthquake.”
According to YVO, signals that are related to human activity can be identified by their prevalence during the daytime hours and their absence during nighttime hours.
Signals related to non-earthquake geologic events far from Yellowstone can also show up on record; YVO confirms the 2022 Hunga Tonga–Hunga Ha’apai volcanic eruption in the south Pacific located 6,053 miles from Yellowstone National Park (YNP) were clearly seen on many stations in the YSN. Non-earthquake signals are also sometimes recorded on seismometers around rivers due to ground shaking from large floods, like the historic flooding in June 2022.
Near Yellowstone Lake, YVO notes seismometers record “icequakes” from cracking of the ice cover during winter, and when the lake is free of ice during summer months ground shaking can be caused by wave action on the lake during daytime hours. Seismometers record signals related to hydrothermal activity and even hydrothermal explosions as well.
