Geophysical imaging of the Yellowstone hydrothermal plumbing system

Whole-rock oxygen isotope ratios as a proxy for the strength and stiffness of hydrothermally altered volcanic rocks

“…The three-dimensional structures and rock property distributions inside volcanic systems are usually inferred using targeted geophysical methods. Electrical methods, such as magnetotellurics and electrical resistivity tomography, have shown to be particularly useful to infer rock alteration distributions in hydrothermal systems because of the influence of secondary minerals in the bulk electrical conductivity of rocks (Rosas-Carbajal et al, 2016;Byrdina et al, 2018;Finn et al, 2022). Petrophysical relations that link these properties are, however, far from obvious.…”

“…Rock physical and mechanical properties are required for large-scale models designed to assess the stability of a lava dome or volcanic flank (Watters et al, 2000;Okubu, 2004;Apuani et al, 2005;Moon et al, 2005;del Potro and Hürlimann, 2008;Heap et al, 2021a, b;Heap and Harnett, 2021;Wallace et al, 2021). The ubiquity of hydrothermal alteration at active volcanoes (Aizawa et al, 2009;Rosas-Carbajal et al, 2016;Byrdina et al, 2017Byrdina et al, , 2018Finn et al, 2018;Tseng et al, 2020;Kereszturi et al, 2021;Finn et al, 2022), and evidence suggesting that alteration compromises volcano stability (van Wyk de Vries et al, 2000;Voight et al, 2002;Salaün et al, 2011), underscores the need for not only understanding the influence of alteration on rock physical and mechanical properties, but also for well constrained properties for altered volcanic rocks, data that are currently rare. In certain scenarios, such as when rock blocks large enough for laboratory experiments cannot be acquired (e.g., drill cuttings from boreholes, when the material is too friable or delicate to prepare samples for laboratory experiments, or when it is impracticable to sample and export a sufficient number of large blocks), or when laboratory equipment is not available, an independent measure of alteration that can be used to estimate the required rock physical and mechanical properties would be extremely useful for routine volcano stability modelling.…”

“…Geophysical techniques have revealed large subsurface hydrothermal systems within active volcanoes worldwide (Aizawa et al, 2009;Finizola et al, 2010;Troll et al, 2012;Rosas-Carbajal et al, 2016;Byrdina et al, 2017Byrdina et al, , 2018Ghorbani et al, 2018;Finn et al, 2018;Ahmed et al, 2018;Tseng et al, 2020;Kereszturi et al, 2021;Finn et al, 2022). The hydrothermal fluids circulating within these systems can physically and chemically alter the rocks (Browne, 1978), which is thought to increase the likelihood of potentially devastating dome or partial edifice flank collapse by compromising their stability (Day, 1996;van Wyk de Vries et al, 2000;Reid et al, 2001;Voight et al, 2002;Reid, 2004;Cecchi et al, 2004;Salaün et al, 2011;Ball et al, 2015, Rosas-Carbajal et al, 2016Ball et al, 2018;Mordensky et al, 2019;Heap et al, 2021a, b;Harnett and Heap, 2021;Darmawan et al, 2022;Mordensky et al, 2022).…”

Time‐Lapse Geophysical Investigation of Geyser Dynamics at Spouter Geyser, Yellowstone National Park: Geyser Dynamics II

“…It is a bulk value influenced by the electrical properties of both the rock and fluid within the measured volume (Friedman, 2005;Gibson & Hinman, 2013;Keller & Frischknecht, 1966). Electrical resistivity geophysical methods are effective in measuring the physical properties of rocks in volcanic environments, such as temperature spatial distributions, fluid saturation conditions, rock permeability, and mineral alteration (Aizawa et al, 2009;Finn et al, 2022;Hill et al, 2015;Peacock et al, 2020Peacock et al, , 2022. These physical properties often vary on measurable timescales and can be monitored with geophysical methods.…”

The Sub‐Ice Structure of Mt. Melbourne Volcanic Field (Northern Victoria Land, Antarctica) Uncovered by High‐Resolution Aeromagnetic Data

“…(2012) along a sub‐vertical cliff about 50–100 m high running N‐S along the entire eastern flank of MM (Figure 4a). The effect of a hydrothermal circulation in a volcanic environment is the loss of magnetization from magnetic minerals contained abundantly on rocks, resulting in a smooth attenuation of magnetic anomalies following the location of geothermal surface manifestations (e.g., Bouligand et al., 2014; Finn et al., 2007; Finn et al., 2022; Finn & Morgan, 2002). This phenomenon has not been observed in the MVF, suggesting the absence of a spread and consistent deep hydrothermal circulation (Figure 4b).…”