Snow suppresses seismic signals from Steamboat Geyser

Much like volcano monitoring, geyser monitoring suffers from temporal, geographic, and instrumental biases. We present a bias identified in seismic monitoring of Steamboat Geyser in Yellowstone National Park, USA. Eruptions of Steamboat are the tallest of any active geyser in the world and they produce broadband signals at two nearby stations in the Yellowstone National Park Seismic Network. In winter, we observe lower signal amplitudes from major eruptions of the geyser at frequencies >22 Hz. Instead of a source effect, we find that environmental conditions affect the recorded signals, which we interpret as a mixture of direct seismic and ground-coupled airwave arrivals. Lower amplitudes are correlated with greater snow depths, and we calculate an energy attenuation coefficient of 0.08 dB per cm of snow. More long-term monitoring is needed at geysers to track changes over time and identify recording biases that may be missed during short, sporadic studies.