Infrasound Monitoring of Multi-Phase Geyser Eruptions at Steamboat Geyser, Yellowstone National Park

We use infrasound monitoring to identify phase transitions between water and steam at Steamboat Geyser in Yellowstone National Park. Using an empirical approach that incorporates first hand observations and time lapse video, we develop infrasound as a tool to monitor eruption parameters. Infrasound is a particularly effective tool for tracking the evolving eruption style and complements other monitoring techniques consisting of seismicity, outflow temperature, and eyewitness observations. Our study utilizes a 13-month acoustic chronology of Steamboat Geyser, recording 23 major eruptions as well as precursory minor activity. Geyser eruptions of Steamboat are multi-phase, ejecting hot water to the surface as either liquid or steam. Typically, a major eruption event at Steamboat starts with a short (< 1 hour) water-dominated phase, during which jetting of water reaches maximum elevations of 120m (400 ft). Following the water-phase, the eruption transitions to a steam-dominated phase that persists for over 12 hours post eruption onset. In 2018, an active period began at Steamboat Geyser resulting in regular eruptive activity for the first time since the 1980s. This afforded an important opportunity to study Steamboat Geyser, which is the tallest erupting geyser in the world. We have taken advantage of Steamboat's activity and used long term continuous infrasound monitoring to discern seasonal trends as well and catalog multiple events with robust eruption statistics. This study highlights the potential benefits and capabilities of infrasound monitoring for tracking geyser activity in Yellowstone at Steamboat and other geyser basins.