Hydrothermal explosion

Last updated September 25, 2023

Hydrothermal explosions occur when superheated water trapped below the surface of the earth rapidly converts from liquid to steam, violently disrupting the confining rock. Boiling water, steam, mud, and rock fragments are ejected over an area of a few meters up to several kilometers in diameter. Although the energy originally comes from a deep igneous source, this energy is transferred to the surface by circulating meteoric water or mixtures of meteoric and magmatic water rather than by magma, as occurs in volcanic eruptions. The energy is stored as heat in hot water and rock within a few hundred feet of the surface.

Cause

Hydrothermal explosions occur where shallow interconnected reservoirs of water at temperatures as high as 250 °C underlie thermal fields. Water usually boils at 100 °C, but under pressure its boiling point increases, causing the water to become superheated. A sudden reduction in pressure causes a rapid phase transition from liquid to steam, resulting in an explosion of water and rock debris.^[2] During the last Ice Age, many hydrothermal explosions were triggered by the release of pressure as glaciers receded.^[3] Other causes are seismic activity, erosion, or hydraulic fracturing.^[4]

Yellowstone

Yellowstone National Park is a thermally active area with an extensive system of hot springs, fumaroles, geysers, and mudpots. There are also several hydrothermal explosion craters, which are not to be confused with calderas, which are collapse features. Eight of these hydrothermal explosion craters are in hydrothermally cemented glacial deposits, and two are in Pleistocene ash-flow tuff.^[1] Each is surrounded by a rim composed of debris derived from the crater, 30 to 100 feet high.^[3]

More than 20 large hydrothermal explosions have occurred at Yellowstone, approximately one every 700 years.^[2] The temperature of the magma reservoir below Yellowstone is believed to exceed 800 °C causing the heating of rocks in the region. If so, the average heat flow supplied by convection currents is 30 times greater than anywhere in the Rocky Mountains. Snowmelt and rainfall seep into the ground at a rapid rate and can conduct enough heat to raise the temperature of ground water to almost boiling.

The phenomena of geyser basins are the product of hot ground water rising close to the surface and occasionally bubbling through. Water temperatures of 238 °C at 332 meters have been recorded at Norris Geyser Basin.^[5] Pocket Basin was originally an ice-dammed lake over a hydrothermal system. Melting ice during the last glacial period caused the lake to rapidly drain, causing a sudden change in pressure triggering a massive hydrothermal explosion.^[1]

Geysers

A hydrothermal explosion is similar to a geyser's eruption except that it includes surrounding rock and mud and does not occur periodically.^[6]

One well-known hydrothermal geyser is Old Faithful which throws up plumes of steam and water approximately every hour and a half on average. Rarely has any steam explosion violently hurled water and rock thousands of feet above the ground; however in Yellowstone's geological history these colossal events have been recorded numerous times and have been found to have created new hills and shaped parts of the landscape.

The largest hydrothermal explosion ever documented was located near the northern edge of Yellowstone Lake, on an embankment commonly known as "Mary Bay". Now consisting of a 1.5 mile crater, it was formed relatively recently, approximately 13,800 years ago. It is believed this crater was formed by a sequence of several hydrothermal explosions in a short time. What triggered this series of events has not yet been clearly established, but volcanologists believe a large earthquake could have played a role by accelerating the melting of nearby glaciers and thus depressurizing the hydrothermal system. Alternatively, rapid changes in the level of Yellowstone Lake may have been responsible.

Recent explosions

Most of Yellowstone's recent large hydrothermal explosions have been the consequence of sudden changes of pressure deep within the hydrothermal system. Generally, these larger explosions have created craters in a north–south pattern (between Norris and Mammoth Hot Springs). It is estimated that all of the known hydrothermal craters were created between 14,000 and 3,000 years ago. Volcanologists believe no magma has ever broken through the fragile crust of Yellowstone Park or stirred the movement of magma in the reservoir beneath Yellowstone.

Related Research Articles

A geyser is a spring characterized by an intermittent discharge of water ejected turbulently and accompanied by steam. As a fairly rare phenomenon, the formation of geysers is due to particular hydrogeological conditions that exist only in a few places on Earth. Generally all geyser field sites are located near active volcanic areas, and the geyser effect is due to the proximity of magma. Generally, surface water works its way down to an average depth of around 2,000 metres (6,600 ft) where it contacts hot rocks. The resultant boiling of the pressurized water results in the geyser effect of hot water and steam spraying out of the geyser's surface vent.

A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

A fumarole is a vent in the surface of the Earth or other rocky planet from which hot volcanic gases and vapors are emitted, without any accompanying liquids or solids. Fumaroles are characteristic of the late stages of volcanic activity, but fumarole activity can also precede a volcanic eruption and has been used for eruption prediction. Most fumaroles die down within a few days or weeks of the end of an eruption, but a few are persistent, lasting for decades or longer. An area containing fumaroles is known as a fumarole field.

A hot spring, hydrothermal spring, or geothermal spring is a spring produced by the emergence of geothermally heated groundwater onto the surface of the Earth. The groundwater is heated either by shallow bodies of magma or by circulation through faults to hot rock deep in the Earth's crust. In either case, the ultimate source of the heat is the radioactive decay of naturally occurring radioactive elements in the Earth's mantle, the layer beneath the crust.

<span class="mw-page-title-main">Stratovolcano</span> Type of conical volcano composed of layers of lava and tephra

A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high to intermediate levels of silica, with lesser amounts of less viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as 15 km (9 mi).

<span class="mw-page-title-main">Old Faithful</span> Geyser in Yellowstone National Park in Wyoming, United States

Old Faithful is a cone geyser in Yellowstone National Park in Wyoming, United States. It was named in 1870 during the Washburn–Langford–Doane Expedition and was the first geyser in the park to be named. It is a highly predictable geothermal feature and has erupted every 44 minutes to two hours since 2000. The geyser and the nearby Old Faithful Inn are part of the Old Faithful Historic District.

The geothermal areas of Yellowstone include several geyser basins in Yellowstone National Park as well as other geothermal features such as hot springs, mud pots, and fumaroles. The number of thermal features in Yellowstone is estimated at 10,000. A study that was completed in 2011 found that a total of 1,283 geysers have erupted in Yellowstone, 465 of which are active during an average year. These are distributed among nine geyser basins, with a few geysers found in smaller thermal areas throughout the Park. The number of geysers in each geyser basin are as follows: Upper Geyser Basin (410), Midway Geyser Basin (59), Lower Geyser Basin (283), Norris Geyser Basin (193), West Thumb Geyser Basin (84), Gibbon Geyser Basin (24), Lone Star Geyser Basin (21), Shoshone Geyser Basin (107), Heart Lake Geyser Basin (69), other areas (33). Although famous large geysers like Old Faithful are part of the total, most of Yellowstone's geysers are small, erupting to only a foot or two. The hydrothermal system that supplies the geysers with hot water sits within an ancient active caldera. Many of the thermal features in Yellowstone build up sinter, geyserite, or travertine deposits around and within them.

Hydrothermal circulation in its most general sense is the circulation of hot water. Hydrothermal circulation occurs most often in the vicinity of sources of heat within the Earth's crust. In general, this occurs near volcanic activity, but can occur in the shallow to mid crust along deeply penetrating fault irregularities or in the deep crust related to the intrusion of granite, or as the result of orogeny or metamorphism. Hydrothermal circulation often results in hydrothermal mineral deposits.

The Lassen volcanic area presents a geological record of sedimentation and volcanic activity in and around Lassen Volcanic National Park in Northern California, U.S. The park is located in the southernmost part of the Cascade Mountain Range in the Pacific Northwest region of the United States. Pacific Oceanic tectonic plates have plunged below the North American Plate in this part of North America for hundreds of millions of years. Heat and molten rock from these subducting plates has fed scores of volcanoes in California, Oregon, Washington and British Columbia over at least the past 30 million years, including these in the Lassen volcanic areas.

The Yellowstone Caldera, sometimes referred to as the Yellowstone Supervolcano, is a volcanic caldera and supervolcano in Yellowstone National Park in the Western United States. The caldera and most of the park are located in the northwest corner of Wyoming. The caldera measures 43 by 28 miles, and postcaldera lavas spill out a significant distance beyond the caldera proper.

A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground water or surface water. The extreme temperature of the magma causes near-instantaneous evaporation of water to steam, resulting in an explosion of steam, water, ash, rock, and volcanic bombs. At Mount St. Helens in Washington state, hundreds of steam explosions preceded the 1980 Plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano.

A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots.

Volcanic gases are gases given off by active volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating from lava, from volcanic craters or vents. Volcanic gases can also be emitted through groundwater heated by volcanic action.

The Waimangu Volcanic Rift Valley is the hydrothermal system created on 10 June 1886 by the volcanic eruption of Mount Tarawera, on the North Island of New Zealand. It encompasses Lake Rotomahana, the site of the Pink and White Terraces, as well as the location of the Waimangu Geyser, which was active from 1900 to 1904. The area has been increasingly accessible as a tourist attraction and contains Frying Pan Lake, which is the largest hot spring in the world, and the steaming and usually pale blue Inferno Crater Lake, the largest geyser-like feature in the world although the geyser itself cannot be seen since it plays at the bottom of the lake.

Frying Pan Lake is the world's largest hot spring. It is located in the Echo Crater of the Waimangu Volcanic Rift Valley, New Zealand and its acidic water maintains a temperature of about 50 to 60 °C (122–140 °F). The Lake covers 38,000 square metres in part of the volcanic crater and the shallow lake is only 5.5 metres (18 ft) deep, but at vents, it can go down to 18.3 metres (60 ft).

<span class="mw-page-title-main">Giantess Geyser</span>

Giantess Geyser is a fountain-type geyser in the Upper Geyser Basin of Yellowstone National Park. It is known for its violent and infrequent eruptions of multiple water bursts that reach from 100 to 200 feet. Eruptions generally occur 2 to 6 times a year. The surrounding area may shake from underground steam explosions just before the initial water and/or steam eruptions. Eruptions may occur twice hourly, experience a tremendous steam phase, and continue activity for 4 to 48 hours. The Geyser last erupted on August 26, 2020 after a six year, 210 day hiatus. A follow-up eruption occurred 15 days later on 10 September 2020. Another eruption occurred on 11 August 2021

Sherman Crater is an active volcanic crater of Mount Baker in the U.S. state of Washington situated between Sherman Peak and Grant Peak.

Seltún Hot Springs, Icelandic pronunciation:[ˈsɛlˌtʰuːn], is a geothermal hot spring system in Krýsuvík volcanic area, in southwest Iceland on the Mid-Atlantic Ridge of the Reykjanes peninsula.

Geothermal activity is a group of natural heat transfer processes, occurring on Earth's surface, caused by the presence of excess heat in the subsurface of the affected area. Geothermal activity can manifest itself in a variety of different phenomena, including, among others, elevated surface temperatures, various forms of hydrothermal activity, and the presence of fumaroles that emit hot volcanic gases.

References

1 2 3 L. J. P Muffler; R, D. E White; A. H Truesdell (March 1971), "Hydrothermal Explosion Craters in Yellowstone National Park", Geological Society of America Bulletin, GSA Bulletin, 82 (3): 723–740, doi:10.1130/0016-7606(1971)82[723:HECIYN]2.0.CO;2
1 2 Morgan, L. A.; Shanks, W. P.; Pierce, K. L. (2006), "Super eruption environments make for "super" hydrothermal explosions: Extreme hydrothermal explosions in Yellowstone National Park", AGU Fall Meeting Abstracts, American Geophysical Union, Fall Meeting 2006, 2006: V33C–0689, Bibcode:2006AGUFM.V33C0689M
1 2 Robert Baer Smith; Lee J. Siegel (2000), Windows into the earth: the geologic story of Yellowstone and Grand Teton national parks, Oxford University Press US, pp. 64–66, ISBN 0-19-510597-4
↑ Rose, William Ingersoll (2004), Natural hazards in El Salvador, Geological Society of America, pp. 246–247, ISBN 0-8137-2375-2
↑ "Supervolcano Yellowstone". Archived from the original on 2014-08-05. Retrieved 2008-05-20.
↑ Angus M. Thuermer (2009-05-25), Yellowstone Explosion: Geologists Witness Rare Yellowstone Explosion, The Jackson Hole News & Guide

External links

A photo of a Hydrothermal explosion

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[muffler-1] 1 2 3 L. J. P Muffler; R, D. E White; A. H Truesdell (March 1971), "Hydrothermal Explosion Craters in Yellowstone National Park", Geological Society of America Bulletin, GSA Bulletin, 82 (3): 723–740, doi:10.1130/0016-7606(1971)82[723:HECIYN]2.0.CO;2

[morgan-2] 1 2 Morgan, L. A.; Shanks, W. P.; Pierce, K. L. (2006), "Super eruption environments make for "super" hydrothermal explosions: Extreme hydrothermal explosions in Yellowstone National Park", AGU Fall Meeting Abstracts, American Geophysical Union, Fall Meeting 2006, 2006: V33C–0689, Bibcode:2006AGUFM.V33C0689M

[smith-3] 1 2 Robert Baer Smith; Lee J. Siegel (2000), Windows into the earth: the geologic story of Yellowstone and Grand Teton national parks, Oxford University Press US, pp. 64–66, ISBN 0-19-510597-4

[4] Rose, William Ingersoll (2004), Natural hazards in El Salvador, Geological Society of America, pp. 246–247, ISBN 0-8137-2375-2

[5] "Supervolcano Yellowstone". Archived from the original on 2014-08-05. Retrieved 2008-05-20.

[6] Angus M. Thuermer (2009-05-25), Yellowstone Explosion: Geologists Witness Rare Yellowstone Explosion, The Jackson Hole News & Guide

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