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

Abstract

Despite more than 200 years of scientific study, the internal dynamics of geyser systems remain poorly characterized. As a consequence, there remain fundamental questions about what processes initiate and terminate eruptions, and where eruptions begin. Over a one-week period in October 2012, we collected down-hole measurements of pressure and temperature in the conduit of an exceptionally regular geyser (132 s/cycle) located in the Chilean desert. We identified four stages in the geyser cycle: (1) recharge of water into the conduit after an eruption, driven by the pressure difference between water in the conduit and in a deeper reservoir; (2) a pre-eruptive stage that follows the recharge and is dominated by addition of steam from below; (3) the eruption, which occurs by rapid boiling of a large mass of water at the top of the water column, and decompression that propagates boiling conditions downward; and (4) a relaxation stage during which pressure and temperature decrease until conditions preceding the recharge stage are restored. Eruptions are triggered by the episodic addition of steam coming from depth, suggesting that the dynamics of the eruptions are dominated by geometrical and thermodynamic complexities in the conduit and reservoir. Further evidence favoring the dominance of internal processes in controlling periodicity is also provided by the absence of responses of the geyser to environmental perturbations (air pressure, temperature and probably also Earth tides).

The Fascinating and Complex Dynamics of Geyser Eruptions

“…Dynamic stresses of >0.5 MPa produced by distant earthquakes can also change eruption intervals. Continuous data from > 4,000 eruptions over a shorter time interval of ∼1 week from a geyser with a 1-2-min IBE in the El Tatio geyser field in Chile show no sensitivity to air temperature, wind, barometric pressure, and solid Earth tides (Munoz-Saez et al 2015a). However, there are year-to-year variations (Munoz-Saez et al 2015b.…”

“…(d) The volumes of shallow (<10 m) exposed geyser cavities at Whakarewarewa range from ∼20 to ∼100 m 3 (Weir et al 1992), significantly larger than erupted volumes. (e) At El Jefe geyser in El Tatio, eruption intervals are insensitive to changes in ambient temperature despite the large amount of cooled water that flows back into the conduit following the eruption (Munoz-Saez et al 2015a). ( f ) Major eruptions of Steamboat Geyser in Yellowstone's Norris Geyser Basin, which with measured eruption jets ∼115 m high is considered the largest geyser in the world, are followed by the gradual drainage of Cistern Spring (∼90 m away) by as much as 4 m (Bryan 2008)-this volume alone is ∼500 m 3 .…”

“…Concurrent measurements of pressure and temperature in the conduits of Old Faithful in Yellowstone (Hutchinson et al 1997) and El Jefe in El Tatio (Munoz-Saez et al 2015a) showed that, following an eruption, water recharge is gradual and much of the heat is added at later stages (Figure 10). Preparation of the geyser for major eruptions is accompanied, in some cases, by minor eruptions, or preplay (see Section 4.2), that may be a manifestation of fluid release from bubble traps and have the thermal consequence of heating water in the conduit.…”

“…Karlstrom et al (2013) found that U 0 at Lone Star geyser in Yellowstone (16-28 m/s) was close to the sound speed for the estimated steam mass fraction. Munoz-Saez et al (2015a) …”

Geyser eruption intervals and interactions: Examples from El Tatio, Atacama, Chile

“…The mud volcano (MV) was a small fumarole in 2012. Most of the 2012 data at El Cobreloa and El Jefe geysers were previously reported by Namiki et al [] and Munoz‐Saez et al [], respectively.…”