The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Shaul Hurwitz - One of the best experts on this subject based on the ideXlab platform.

  • the fascinating and complex dynamics of Geyser eruptions
    Annual Review of Earth and Planetary Sciences, 2017
    Co-Authors: Shaul Hurwitz, Michael Manga
    Abstract:

    Geysers episodically erupt liquid and vapor. Despite two centuries of scientific study, basic questions persist—why do Geysers exist? What determines eruption intervals, durations, and heights? What initiates eruptions? Through monitoring eruption intervals, analyzing geophysical data, taking measurements within Geyser conduits, performing numerical simulations, and constructing laboratory models, some of these questions have been addressed. Geysers are uncommon because they require a combination of abundant water recharge, magmatism, and rhyolite flows to supply heat and silica, and large fractures and cavities overlain by low-permeability materials to trap rising multiphase and multicomponent fluids. Eruptions are driven by the conversion of thermal to kinetic energy during decompression. Larger and deeper cavities permit larger eruptions and promote regularity by isolating water from weather variations. The ejection velocity may be limited by the speed of sound of the liquid + vapor mixture.

  • dissolved gases in hydrothermal phreatic and Geyser eruptions at yellowstone national park usa
    Geology, 2016
    Co-Authors: Shaul Hurwitz, Andrew G Hunt, Laura E Clor, Blaine R Mccleskey, Kirk D Nordstrom, William C Evans
    Abstract:

    Multiphase and multicomponent fluid flow in the shallow continental crust plays a significant role in a variety of processes over a broad range of temperatures and pressures. The presence of dissolved gases in aqueous fluids reduces the liquid stability field toward lower temperatures and enhances the explosivity potential with respect to pure water. Therefore, in areas where magma is actively degassing into a hydrothermal system, gas-rich aqueous fluids can exert a major control on geothermal energy production, can be propellants in hazardous hydrothermal (phreatic) eruptions, and can modulate the dynamics of Geyser eruptions. We collected pressurized samples of thermal water that preserved dissolved gases in conjunction with precise temperature measurements with depth in research well Y-7 (maximum depth of 70.1 m; casing to 31 m) and five thermal pools (maximum depth of 11.3 m) in the Upper Geyser Basin of Yellowstone National Park, USA. Based on the dissolved gas concentrations, we demonstrate that CO 2 mainly derived from magma and N 2 from air-saturated meteoric water reduce the near-surface saturation temperature, consistent with some previous observations in Geyser conduits. Thermodynamic calculations suggest that the dissolved CO 2 and N 2 modulate the dynamics of Geyser eruptions and are likely triggers of hydrothermal eruptions when recharged into shallow reservoirs at high concentrations. Therefore, monitoring changes in gas emission rate and composition in areas with neutral and alkaline chlorine thermal features could provide important information on the natural resources (Geysers) and hazards (eruptions) in these areas.

  • eruptions at lone star Geyser yellowstone national park usa 2 constraints on subsurface dynamics
    Journal of Geophysical Research, 2014
    Co-Authors: Jean Vandemeulebrouck, Michael Manga, Shaul Hurwitz, Robert A Sohn, Maxwell L Rudolph, Malcolm J S Johnston, Adam S Soule, Darcy K Mcphee, Jonathan M G Glen, Leif Karlstrom
    Abstract:

    We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star Geyser in Yellowstone National Park to identify key subsurface processes throughout the Geyser's eruption cycle. Previously, we described measurements and analyses associated with the Geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the Geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the Geyser is controlled by the thermo-mechanical coupling between the Geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the Geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from Geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.

  • triggering and modulation of Geyser eruptions in yellowstone national park by earthquakes earth tides and weather
    Journal of Geophysical Research, 2014
    Co-Authors: Shaul Hurwitz, Robert A Sohn, Karen Luttrell, Michael Manga
    Abstract:

    We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful Geysers in Yellowstone National Park. We focus our statistical analysis on the response of these Geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these Geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool Geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone Geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy Geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual Geyser IBE variability is dominated by internal processes and interaction with other Geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.

  • eruptions at lone star Geyser yellowstone national park usa 1 energetics and eruption dynamics
    Journal of Geophysical Research, 2013
    Co-Authors: Leif Karlstrom, Michael Manga, Shaul Hurwitz, Robert A Sohn, Jean Vandemeulebrouck, Fred Murphy, Maxwell L Rudolph, Malcolm J S Johnston, Blaine R Mccleskey
    Abstract:

    [1] Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infrared intensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every 3 h. We define four phases in the eruption cycle (1) a 28 ˙ 3 min phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s –1 , steam mass fraction of less than � 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; (2) a 26 ˙ 8 min posteruption relaxation phase with no discharge from the vent, infrared (IR), and acoustic power oscillations gliding between 30 and 40 s; (3) a 59 ˙ 13 min recharge period during which the Geyser is quiescent and progressively refills, and (4) a 69 ˙ 14 min preplay period characterized by a series of 5–10 min long pulses of steam, small volumes of liquid water discharge, and 50

Michael Manga - One of the best experts on this subject based on the ideXlab platform.

  • geometry of Geyser plumbing inferred from ground deformation
    Journal of Geophysical Research, 2019
    Co-Authors: Alberto Ardid, Michael Manga, Carolina Munozsaez, Emilio Vera, Cyndi Kelly, Andrei Maksymowicz, Francisco Ortegaculaciati
    Abstract:

    Author(s): Ardid, A; Vera, E; Kelly, C; Manga, M; Munoz-Saez, C; Maksymowicz, A; Ortega-Culaciati, F | Abstract: ©2019. American Geophysical Union. All Rights Reserved. Broadband seismic data were recorded on the ground surface around an exceptionally regular eruptive system, Geyser El Jefe, in the El Tatio Geyser field, Chile. We identify two stages in the eruption, recharge and discharge, characterized by a radial expansion and contraction, respectively, of the surface around the Geyser. We model the deformation with spherical sources that vary in size, location, and pressure, constrained by pressure observations inside the conduit that are highly correlated with deformation signals. We find that in order to fit the data, the subsurface pressure sources must be laterally offset from the Geyser vent during the recharge phase and that they must migrate upward toward the vent during the eruption phase. This pattern is consistent with models in which ascending fluids accumulate and then are released from a bubble trap that is horizontally offset from the shallow conduit of the Geyser.

  • the fascinating and complex dynamics of Geyser eruptions
    Annual Review of Earth and Planetary Sciences, 2017
    Co-Authors: Shaul Hurwitz, Michael Manga
    Abstract:

    Geysers episodically erupt liquid and vapor. Despite two centuries of scientific study, basic questions persist—why do Geysers exist? What determines eruption intervals, durations, and heights? What initiates eruptions? Through monitoring eruption intervals, analyzing geophysical data, taking measurements within Geyser conduits, performing numerical simulations, and constructing laboratory models, some of these questions have been addressed. Geysers are uncommon because they require a combination of abundant water recharge, magmatism, and rhyolite flows to supply heat and silica, and large fractures and cavities overlain by low-permeability materials to trap rising multiphase and multicomponent fluids. Eruptions are driven by the conversion of thermal to kinetic energy during decompression. Larger and deeper cavities permit larger eruptions and promote regularity by isolating water from weather variations. The ejection velocity may be limited by the speed of sound of the liquid + vapor mixture.

  • Geyser eruption intervals and interactions examples from el tatio atacama chile
    Journal of Geophysical Research, 2015
    Co-Authors: Carolina Munozsaez, Atsuko Namiki, Michael Manga
    Abstract:

    We compare and contrast data collected in 2012 and 2014 from the El Tatio Geyser field, Chile. We identify Geyser systems that evolve over time, including changes in the interval between eruptions, development of new thermal features, and interactions between Geysers. We study three different cases: (a) an isolated Geyser, which is periodic and has nearly identical eruptions every cycle; (b) a Geyser and coupled noneruptive pool, where the Geyser has nonregular cycles and several preplay eruptions before the main eruption; and (c) two Geysers and a mud volcano, which have nonregular cycles and are all interacting. Though Geysers erupt with different styles, we recognize some common features: the conduit recharges with liquid during the quiescent period, bubbles enter the conduit before eruptions, and eruptions occur when water boils in the upper part of the conduit. The episodic addition of heat may govern the periodicity, while the depth where heat is added dictates the eruption style: conduits with deeper heat input are more likely to show preplay or minor eruptions. The interactions between thermal features can be explained by pressure transmission in subsurface permeable layers between Geyser conduits.

  • eruptions at lone star Geyser yellowstone national park usa 2 constraints on subsurface dynamics
    Journal of Geophysical Research, 2014
    Co-Authors: Jean Vandemeulebrouck, Michael Manga, Shaul Hurwitz, Robert A Sohn, Maxwell L Rudolph, Malcolm J S Johnston, Adam S Soule, Darcy K Mcphee, Jonathan M G Glen, Leif Karlstrom
    Abstract:

    We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star Geyser in Yellowstone National Park to identify key subsurface processes throughout the Geyser's eruption cycle. Previously, we described measurements and analyses associated with the Geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the Geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the Geyser is controlled by the thermo-mechanical coupling between the Geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the Geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from Geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.

  • Geyser preplay and eruption in a laboratory model with a bubble trap
    Journal of Volcanology and Geothermal Research, 2014
    Co-Authors: Esther Adelstein, Alexander Shteinberg, Aaron Tran, Carolina Munoz Saez, Michael Manga
    Abstract:

    article i nfo Boiling Eruption Conduit Preplay We present visual observations and temperature measurements from a laboratory model of a Geyser. Our model incorporates a bubble trap, a zone in which vapor can accumulate in the Geyser's subsurface plumbing, in a ver- tical conduit connected to a basal chamber. Analogous features have been identified at several natural Geysers. Weobserve threetypesof eruptions:1) rising bubblesejecta smallvolume of liquidina weak spout(smallerup- tion);2)boilingoccursintheconduitabovethebubbletrap(mediumeruption);and3)boilingoccursinthecon- duitandchamber(large eruption).Inthelasttwocases,boilingintheconduitcausesarapidhydrostaticpressure dropthatallows for the rise anderuptionofliquidwaterina vigorousspout.Boiling initiatesatdepth rather than propagating downward from the surface. In a single eruption cycle, multiple small eruptions precede every medium and large eruption. At least one eruption cycle that culminates in a medium eruption (i.e., a quiescent period followed by a series of small eruptions leading up to a medium eruption) precedes every eruption cycle thatculminatesinalarge eruption.We findthatthe transferof fluidwithhighenthalpytotheupperconduitdur- ingsmallandmediumeruptionsisnecessarytoheattheupperconduitandpreparethesystemforthefullboiling required for a large eruption. The placement of the bubble trap midway up the conduit allows for more efficient heatingoftheupperconduit.Ourmodelprovidesinsightintotheinfluenceofconduitgeometryoneruptionstyle and the importance of heat transfer by smaller events in preparing the Geyser system for eruption.

Robert A Sohn - One of the best experts on this subject based on the ideXlab platform.

  • fluid oscillations in a laboratory Geyser with a bubble trap
    Journal of Volcanology and Geothermal Research, 2018
    Co-Authors: Maxwell L Rudolph, Robert A Sohn
    Abstract:

    Abstract Geysers are rare geologic features that episodically erupt water and steam. While it is understood that the eruptions are triggered by the conversion of thermal to kinetic energy during decompression of hot fluids, Geysers commonly exhibit a range of dynamic behaviors in-between and during eruptions that have yet to be adequately explained. In-situ measurements of temperature and pressure as well as remote geophysical techniques have revealed oscillatory behavior across a range of timescales from eruption cycles to impulsive bubble collapse events. Many Geysers, including Old Faithful in Yellowstone National Park, USA, are believed to have laterally-offset subsurface reservoirs (referred to as a ‘bubble trap’) that can trap and accumulate noncondensable gas or steam entering the system. The impact of a bubble trap on the dynamic behaviors of the system, however, has not been fully established. We constructed a laboratory bubble trap and performed a series of experiments to study how fluids oscillate back and forth between the eruption conduit and laterally-offset reservoir in-between eruptions. We present a new theoretical model based on Hamiltonian mechanics that successfully predicts the oscillation frequencies observed in our experiments based on the conduit system geometry, the amount of gas that has accumulated in the bubble trap, and the amount of liquid water in the system. We demonstrate that when scaled to Old Faithful Geyser, this mechanism is capable of producing oscillations at the observed frequencies.

  • eruptions at lone star Geyser yellowstone national park usa 2 constraints on subsurface dynamics
    Journal of Geophysical Research, 2014
    Co-Authors: Jean Vandemeulebrouck, Michael Manga, Shaul Hurwitz, Robert A Sohn, Maxwell L Rudolph, Malcolm J S Johnston, Adam S Soule, Darcy K Mcphee, Jonathan M G Glen, Leif Karlstrom
    Abstract:

    We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star Geyser in Yellowstone National Park to identify key subsurface processes throughout the Geyser's eruption cycle. Previously, we described measurements and analyses associated with the Geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the Geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the Geyser is controlled by the thermo-mechanical coupling between the Geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the Geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from Geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.

  • triggering and modulation of Geyser eruptions in yellowstone national park by earthquakes earth tides and weather
    Journal of Geophysical Research, 2014
    Co-Authors: Shaul Hurwitz, Robert A Sohn, Karen Luttrell, Michael Manga
    Abstract:

    We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful Geysers in Yellowstone National Park. We focus our statistical analysis on the response of these Geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these Geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool Geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone Geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy Geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual Geyser IBE variability is dominated by internal processes and interaction with other Geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.

  • eruptions at lone star Geyser yellowstone national park usa 1 energetics and eruption dynamics
    Journal of Geophysical Research, 2013
    Co-Authors: Leif Karlstrom, Michael Manga, Shaul Hurwitz, Robert A Sohn, Jean Vandemeulebrouck, Fred Murphy, Maxwell L Rudolph, Malcolm J S Johnston, Blaine R Mccleskey
    Abstract:

    [1] Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infrared intensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every 3 h. We define four phases in the eruption cycle (1) a 28 ˙ 3 min phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s –1 , steam mass fraction of less than � 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; (2) a 26 ˙ 8 min posteruption relaxation phase with no discharge from the vent, infrared (IR), and acoustic power oscillations gliding between 30 and 40 s; (3) a 59 ˙ 13 min recharge period during which the Geyser is quiescent and progressively refills, and (4) a 69 ˙ 14 min preplay period characterized by a series of 5–10 min long pulses of steam, small volumes of liquid water discharge, and 50

William C Evans - One of the best experts on this subject based on the ideXlab platform.

  • dissolved gases in hydrothermal phreatic and Geyser eruptions at yellowstone national park usa
    Geology, 2016
    Co-Authors: Shaul Hurwitz, Andrew G Hunt, Laura E Clor, Blaine R Mccleskey, Kirk D Nordstrom, William C Evans
    Abstract:

    Multiphase and multicomponent fluid flow in the shallow continental crust plays a significant role in a variety of processes over a broad range of temperatures and pressures. The presence of dissolved gases in aqueous fluids reduces the liquid stability field toward lower temperatures and enhances the explosivity potential with respect to pure water. Therefore, in areas where magma is actively degassing into a hydrothermal system, gas-rich aqueous fluids can exert a major control on geothermal energy production, can be propellants in hazardous hydrothermal (phreatic) eruptions, and can modulate the dynamics of Geyser eruptions. We collected pressurized samples of thermal water that preserved dissolved gases in conjunction with precise temperature measurements with depth in research well Y-7 (maximum depth of 70.1 m; casing to 31 m) and five thermal pools (maximum depth of 11.3 m) in the Upper Geyser Basin of Yellowstone National Park, USA. Based on the dissolved gas concentrations, we demonstrate that CO 2 mainly derived from magma and N 2 from air-saturated meteoric water reduce the near-surface saturation temperature, consistent with some previous observations in Geyser conduits. Thermodynamic calculations suggest that the dissolved CO 2 and N 2 modulate the dynamics of Geyser eruptions and are likely triggers of hydrothermal eruptions when recharged into shallow reservoirs at high concentrations. Therefore, monitoring changes in gas emission rate and composition in areas with neutral and alkaline chlorine thermal features could provide important information on the natural resources (Geysers) and hazards (eruptions) in these areas.

  • temporal variations of Geyser water chemistry in the upper Geyser basin yellowstone national park usa
    Geochemistry Geophysics Geosystems, 2012
    Co-Authors: Shaul Hurwitz, Andrew G Hunt, William C Evans
    Abstract:

    [1] Geysers are rare features that reflect a delicate balance between an abundant supply of water and heat and a unique geometry of fractures and porous rocks. Between April 2007 and September 2008, we sampled Old Faithful, Daisy, Grand, Oblong, and Aurum Geysers in Yellowstone National Park's Upper Geyser Basin and characterized temporal variations in major element chemistry and water isotopes (δ18O, δD, 3H). We compare these temporal variations with temporal trends of Geyser Eruption Intervals (GEI). SiO2 concentrations and geothermometry indicate that the Geysers are fed by waters ascending from a reservoir with temperatures of ∼190 to 210°C. The studied Geysers display small and complex chemical and isotopic seasonal variations, and Geysers with smaller volume display larger seasonal variations than Geysers with larger volumes. Aurum and Oblong Geysers contain detectable tritium concentrations, suggesting that erupted water contains some modern meteoric water. We propose that seasonal GEI variations result from varying degrees of evaporation, meteoric water recharge, water table fluctuations, and possible hydraulic interaction with the adjacent Firehole River. We demonstrate that the concentrations of major dissolved species in Old Faithful Geyser have remained nearly constant since 1884 despite large changes in Old Faithful's eruption intervals, suggesting that no major changes have occurred in the hydrothermal system of the Upper Geyser Basin for >120 years. Our data set provides a baseline for monitoring future changes in Geyser activity that might result from varying climate, earthquakes, and changes in heat flow from the underlying magmatic system.

Leif Karlstrom - One of the best experts on this subject based on the ideXlab platform.

  • eruptions at lone star Geyser yellowstone national park usa 2 constraints on subsurface dynamics
    Journal of Geophysical Research, 2014
    Co-Authors: Jean Vandemeulebrouck, Michael Manga, Shaul Hurwitz, Robert A Sohn, Maxwell L Rudolph, Malcolm J S Johnston, Adam S Soule, Darcy K Mcphee, Jonathan M G Glen, Leif Karlstrom
    Abstract:

    We use seismic, tilt, lidar, thermal, and gravity data from 32 consecutive eruption cycles of Lone Star Geyser in Yellowstone National Park to identify key subsurface processes throughout the Geyser's eruption cycle. Previously, we described measurements and analyses associated with the Geyser's erupting jet dynamics. Here we show that seismicity is dominated by hydrothermal tremor (~5–40 Hz) attributed to the nucleation and/or collapse of vapor bubbles. Water discharge during eruption preplay triggers high-amplitude tremor pulses from a back azimuth aligned with the Geyser cone, but during the rest of the eruption cycle it is shifted to the east-northeast. Moreover, ~4 min period ground surface displacements recur every 26 ± 8 min and are uncorrelated with the eruption cycle. Based on these observations, we conclude that (1) the dynamical behavior of the Geyser is controlled by the thermo-mechanical coupling between the Geyser conduit and a laterally offset reservoir periodically filled with a highly compressible two-phase mixture, (2) liquid and steam slugs periodically ascend into the shallow crust near the Geyser system inducing detectable deformation, (3) eruptions occur when the pressure decrease associated with overflow from Geyser conduit during preplay triggers an unstable feedback between vapor generation (cavitation) and mass discharge, and (4) flow choking at a constriction in the conduit arrests the runaway process and increases the saturated vapor pressure in the reservoir by a factor of ~10 during eruptions.

  • eruptions at lone star Geyser yellowstone national park usa 1 energetics and eruption dynamics
    Journal of Geophysical Research, 2013
    Co-Authors: Leif Karlstrom, Michael Manga, Shaul Hurwitz, Robert A Sohn, Jean Vandemeulebrouck, Fred Murphy, Maxwell L Rudolph, Malcolm J S Johnston, Blaine R Mccleskey
    Abstract:

    [1] Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a 4 day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infrared intensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every 3 h. We define four phases in the eruption cycle (1) a 28 ˙ 3 min phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s –1 , steam mass fraction of less than � 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; (2) a 26 ˙ 8 min posteruption relaxation phase with no discharge from the vent, infrared (IR), and acoustic power oscillations gliding between 30 and 40 s; (3) a 59 ˙ 13 min recharge period during which the Geyser is quiescent and progressively refills, and (4) a 69 ˙ 14 min preplay period characterized by a series of 5–10 min long pulses of steam, small volumes of liquid water discharge, and 50