A geyser is a vent in Earth's surface that periodically ejects
a column of hot water and steam. Even a small geyser is an amazing
phenomenon; however some geysers have eruptions that blast thousands
of gallons of boiling hot water up to a few hundred feet in the air.
Old Faithful is the world's best known geyser. It is located in
Yellowstone National Park (USA). Old Faithful erupts every 60 to
90 minutes and blasts a few thousand gallons of boiling hot water
between 100 and 200 feet into the air.
Conditions Required for a Geyser
Geysers are extremely rare features. They occur only where
there is a coincidence of unusual conditions. Worldwide there
are only about 1000 geysers and most of those are located in
Yellowstone National Park (USA).
Conditions Required for Geysers
1) hot rocks below
2) an ample ground water source
3) a subsurface water reservoir
4) fissures to deliver water to the surface
Where are Geysers Found?
Most of the world's geysers occur in just five
countries: 1) the United States, 2) Russia, 3) Chile, 4) New
Zealand and 5) Iceland. All of these locations are where there is
geologically recent volcanic activity and a source of hot rock
below.
Geysers in the United States
Umnak Island, Alaska
Kanaga Island, Alaska
Lassen Volcanic National Park, California
Long Valley Caldera, California
Hot Creek and Little Hot Creek, California
Morgan Springs, California
Salton Sea, California (extinct)
Beowawe Geyser Field, Nevada (extinct)
Black Rock Desert, Nevada
Great Boiling Springs, Nevada
Steamboat Springs, Nevada (extinct)
Mickey Hot Springs, Oregon
Countries With Many Active Geysers
1) United States - Yellowstone National Park
2) Russia - Dolina Geiserov
3) Chile - El Tatio
4) New Zealand - Taupo Volcanic Zone
5) Iceland - Many locations
Map of Active Geyser Fields
Map showing the location of world countries with active geyser fields.
YouTube video of Old Faithful Geyser in eruption at Yellowstone National Park. Note how many people are present to witness the eruption!
YouTube video of Iceland's Strokkur Geyser in eruption. Strokkur erupts to heights of up to 70 feet about every 10 to 20 minutes.
How Often Do Geysers Erupt?
Most geysers erupt irregularly and infrequently. However,
a few are known for regular eruptions. The most famous,
named "Old Faithful" in recognition of its regular eruptions,
is located in Yellowstone National Park (USA) and erupts about every 60 to 90 minutes. More details on the eruption intervals of Yellowstone geysers is given in the table below.
Old Faithful is Getting Slower
Research done at the United States Geological Survey suggests that long-term drought conditions in the Yellowstone area have lenghtened the time interval between Old Faithful's eruptions. The delay is thought to be caused by a smaller water supply.
Data from National Park Service (Measurements done in 2002)
Which Geyser is the World's Largest?
The tallest active geyser in the world is Steamboat
Geyser in Yellowstone National Park. Some of its eruptions
blast water over 300 feet into the air. Don't go to Yellowstone
expecting to see it erupt because it has erupted less than ten
times in the last twenty years.
Waimangu Geyser in New Zealand
used to be the tallest geyser in the world. Its eruptions were
spectacular, blasting jets of water up to 1600 feet in the air.
Unfortunately, a landslide altered the hydrology around Wiamangu
and it has not erupted since 1902.
How Do Geysers Work?
To understand how a geyser works, you must first understand the
relationship between water and steam. Steam is a gaseous form
of water. Steam is produced when water is heated to its boiling
point. When water converts into steam at surface conditions it
undergoes an enormous expansion because steam occupies 1600 times
as much space as the original volume of original water. The eruption
of a geyser is powered by a "steam explosion" when boiling hot water
suddenly expands into the much more voluminous steam.
To summarize: a geyser erupts when superheated ground water, confined at depth,
becomes hot enough to blast its way to the surface.
Here's what
happens in the ground...
Cool ground water near the surface percolates down into the
earth. As it approaches a heat source below, such as a hot
magma chamber, it is steadily heated towards its boiling point.
However, at the boiling point the water does not convert into
steam. This is because it is deep below the ground and the weight of
cooler water above produces a high confining pressure. This
condition is know as "superheated" - the water is hot enough to become
steam - it wants to become steam - but it unable to expand because
of the high confining pressure.
At some point the deep water becomes hot enough, or the confining
pressure is reduced, and the frustrated water explodes into
steam in an enormous expansion of volume. This "steam explosion"
blasts the confining water out of the vent as a geyser.
Are There Geysers on Other Planets?
So far, geysers have not been discovered on other planets, however,
geyser-like activity has been documented on some of the moons in
our solar system. Jupiter's moon, Io, has eruptions of frozen water
particles and other gases through vents in its surface. Triton, a moon
of Neptune, and Enceladus, a moon of Saturn, also have these cold geysers
sometimes called "cryovolcanoes". They are thought to erupt from
pools of liquid water located a short distance below the the surface of
these moons. On the surface the eruptions are like a "volcanic snow".
