The Anatomy Of Yellowstone Hydrothermal Systems and Their Related Hazards

Old Faithful Anatomy And Magma from Earth’s Core Fueling Yellowstone’s Volcanism, Earthquake Shaking, Extraordinary Ground Movements And Its Geysers and Hot Springs

July 16th (Tuesday), 6 p.m., Teton Co. Library Auditorium – Open to Public. Presentation: The Anatomy Of Yellowstone Hydrothermal Systems and Their Related Hazards”, Presented by Bob Smith, University of Utah.

The University of Utah has conducted detailed seismic, GPS and geologic studies of the plumbing anatomy of Upper Geyser Basin and Old Faithful the world renown and iconic geyser of Yellowstone in order to determine its 4D structure and dynamic eruption properties.  These studies reveal that Old Faithful is located at the edge of large hydrothermal reservoir only 10 to 60 m deep and composed of highly fractured rock, hot water and steam. This extensive hydrothermal reservoir is located west of the geyser, extending a km beneath the Old Faithful Lodge and other infrastructure.  We discovered that Old Faithful eruptions do not have a notable seismic signal but have large precursory episodes of harmonic tremor every ~95 minutes just prior to the eruption.

More broadly I will show that Yellowstone earthquakes are dominated by intense swarms of earthquakes experiencing tens of thousands of small events occurring in a few minutes, to a few days to weeks, etc. indicating, “Yellowstone is always shaking”. This style of seismicity makes up more than 60% of Yellowstone earthquakes, as highlighted by the recent 2017-18 Maple Creek swarm. This sequence links the aftershocks of the 1858 deadly M 7.3 Hebgen Lake MT earthquake that extends 50 km to the Norris Geyser Basin and contains volcanic related earthquake clusters on the NW edge of the Yellowstone crustal magma reservoir.  I will show how Yellowstone’s immense volcanic system is driven by a giant mantle convection system originating 2700 km deep at the core-mantle boundary, creating a magmatic plume of partly molten rock rising in a conduit upward to 70 km beneath Yellowstone. This then sends magma into two shallow Yellowstone crustal reservoirs as shallow as 5 km beneath Old Faithful. 

Related University of Utah work continues detailed seismic and GPS studies of the world’s tallest geyser, Steamboat, where I will show the initial results from seismic monitoring of this the world’s largest geyser and also of new studies of the submerged northern Yellowstone Lake hydrothermal system.  Overall our research demonstrates that the geodynamics of the entire 400 km wide Yellowstone Plateau is created by magma-plume buoyancy that has had a profound impact on the geologic evolution of most of the western U.S. This can be demonstrated to be the case since Yellowstone volcanism began 16 million years ago & 800 km to the west, as the mantle plume interacted with the bottom of the North American continent that moved SW at 2.5 cm/yr.