Eruptions at Lone Star Geyser, Yellowstone National Park, USA: 1. Energetics and eruption dynamics

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 50-70 s flow oscillations. The erupted waters ascend from a 160-170 ı C reservoir, and the volume discharged during the entire eruptive cycle is 20.8˙4.1 m 3 . Assuming isentropic expansion, we calculate a heat output from the geyser of 1.4-1.5 MW, which is < 0.1% of the total heat output from Yellowstone Caldera.

Dynamics within geyser conduits, and sensitivity to environmental perturbations: Insights from a periodic geyser in the El Tatio geyser field, Atacama Desert, Chile

“…Previous authors (e.g., Kieffer, 1984;Karlstrom et al, 2013, Namiki et al, 2014Adelstein et al, 2014) described a preparation stage preceding major eruptions called "pre-play", which is characterized by pulses of liquid and/or steam discharge. At El Jefe we also document a preparatory phase in the form of the oscillations preceding every eruption, but without surface discharge.…”

“…The mass flow rate is smaller than at Lone Star geyser in Yellowstone National Park, 1.9 kg/s (Karlstrom et al, 2013), and Old Faithful, 7.0-8.3 kg/s, using a measured discharge of 38-45 m 3 (Allen and Day, 1935).…”

“…The equilibrium sound speed of water + steam mixtures with a vapor mass fraction of 5 × 10 − 5 is U~1 m/s (the nonequilibrium sound speed is N 40 m/s; Karlstrom et al, 2013). The fundamental mode for a water column height of 0.85 m (approximate water level from the bottom of the conduit before eruption) is then~3.4 s (0.3 Hz).…”

“…Geysers are uncommon; less than 1000 have been described worldwide, and this number is decreasing due to geothermal energy development (Bryan, 1995). Special conditions are needed for their formation: a supply of water, a source of heat, and a particular system of fractures and/or porous rocks to permit episodic discharge (e.g., White, 1967;Fournier, 1969;Kieffer, 1989;Rojstaczer, 1993, 1996;Kedar et al, 1998;Kiryukhin et al, 2012;Belousov et al, 2013;Karlstrom et al, 2013;Shteinberg et al, 2013;Vandemeulebrouck et al, 2013;Namiki et al, 2014;Vandemeulebrouck et al, 2014).…”

Researching the Earth—and a Few of Its Neighbors

“…The variability of seismic signals caused by heterogeneity in wet geothermal ground observed in Yellowstone (Kieffer 1984b) has been cited as an analog for variable seismicity in subaqueous hydrothermal settings (Pontbriand & Sohn 2014). The low sound speed of erupting fluid causes intervals of choked flow during eruptions of Lone Star Geyser, at Yellowstone National Park (Karlstrom et al 2013). These concepts have been generalized to multicomponent magmatic systems, for example, to explain the resonant frequencies of acoustic-gravity waves in a bubbly magma column capped by a lava lake (Karlstrom & Dunham 2016) or to provide constraints on igneous dikes excavating sill magmas in the context of collapse pits along a lunar rille (Wilson et al 2011).…”