Geothermal Areas Around the World

 

Hot springs at West Thumb Thermal area in Yellowstone

In this chapter we look at specific areas in the world where geysers, mud pots, etc. are found. It is usual that all these geothermal features occur in a cluster rather than an isolated feature being present. As mentioned earlier, hot springs are by far the most common features and occur in thermal areas as well as in isolated spots. From the previous chapter, we know that there are common underlying characteristics that make geysers, fumaroles, mud pots, hot springs, and terraces, just various manifestations of the same concept: an underground magma chamber, hot water/steam, trapped gases under a thin crust of earth, with channels, or "plumbing" connecting the chamber to the surface. So where are these hot spots present?

Here we address the questions of Where are these thermal features found? and When do they occur?

Geothermal features are not common geological features. They occur in clusters, in a few widely separated locations of the world where the conditions are right for their occurrence. In this chapter we look at the most famous of these locations: Yellowstone (USA), North Island (New Zealand), Iceland, Kamchatka (Russia), and Japan. Besides the ones discussed in detail, there are a few isolated geysers in Chile, Mexico, some parts of Africa, Indonesia, some Pacific islands, China, etc. Different regions of the world have been geothermally active at different periods in the geological timescale. Some geysers become dormant, others are born because of new rumblings beneath the earth's crust, hot springs turn into geysers and vice-versa. Clearly, all these features have a lifetime, ranging from a few days to hundreds of years. Their lifetime depends on the factors we discussed in the previous chapter - the changing conditions that cause them to occur or disappear. We will see a few examples of these changes in this chapter, as we discuss specific areas and individual features.

Typical Geyser Basins

Surface features found in a typical geyser basin

All the geyser basins, or geothermally active areas, have typical features that make them look similar, wherever they are located in the world. The illustration shows the surface features found in a typical geyser basin.

[TODO]: Make a fresh illustration of a typical geyser basin

[TODO]: Make an illustration of the cross section of the plumbing of a geyser basin from the Yellowstone NP brochure.

The exact number of geysers in any of the major thermal areas described below varies from time to time. These numbers are quoted differently by different sources, according to how dramatic they want it to seem! J In any case, the exact number of geysers or thermal features is not important. You only need to get an overall picture of the various areas of the world where these features occur in sizeable numbers.

In Yellowstone, out of 2000-odd hot springs, about 200 (roughly 10%) are actually geysers. Contrast this with Iceland, where out of roughly 3000 hot springs, only 40 are active geysers (only about 1.33%). New Zealand has even fewer geysers, although the largest geyser ever known to humans was present in New Zealand. It is the now inactive Waimangu Geyser. There are about 100 geysers in Kamchatka valley in Russia, of which about 20 are comparable in size to the ones in Yellowstone.

Let us look closely at some of these famous geyser basins of the world.

Yellowstone National Park, USA

[TODO]: Make a map of the Yellowstone caldera from the Yellowstone NP brochure.

Yellowstone National Park, located in northwestern United States, has by far the most number of geysers and largest area of geothermal activity. Volcanic activity has always been a prominent force in the Yellowstone area in the past and present. It is predicted to continue to shape that area in the future also.

How did this area evolve to its present day state of hundreds of geysers?

A geyser in Norris Basin
Steam rising from the Grand Prismatic Spring in Midway Basin

Old engraving of Beehive Geyser

There were multiple enormous volcanic eruptions in Yellowstone, spread out in the past: one about 2 million years ago, then about 1.2 million years ago, another about 600,000 years ago. The last eruption spread lava and debris over approximately 1000 cubic kms. Today the US government has demarcated the area as a national park, which is protected environmentally and ecologically. The central portion of what is now called Yellowstone National Park (NP) collapsed long ago, forming a 45 x 75 km caldera, or basin. See [TODO] illustration for the map of the Yellowstone area at its present state. The heat from the volcanic magma from those eruptions long ago, still powers the geysers and other features of Yellowstone.

As Yellowstone is a vast area, the rest of this section describes localized thermal areas within Yellowstone. All these areas are marked on the [TODO] map above.

Upper Geyser Basin

The Upper Geyser Basin of Yellowstone is truly a spectacular sight. Many travelers have stated that it is the most magnificent of all thermal areas in the world. There are about 70 geysers in this area alone. As researchers study them regularly, all of them have been given names. Some of the noteworthy geysers are Old Faithful, Grand, Castle, Giant, Giantess, Grotto, Daisy, Riverside, Anemone, Lion group, Beehive, Artemisia. [TODO] link scanned photos of these geysers where possible.

Each geyser has its characteristic eruption style and it is awe-inspiring to watch the larger ones in action.

Norris Geyser Basin

The Norris Basin, named after Yellowstone Park's first superintendent, P.W.Norris, roughly has the dimensions of 15 X 1.5 sq.km. With a high ridge on one side and the Gibbon River on the other side, it is a shallow depression in between. One portion of this basin, known as Porcelain Basin, is especially colourful, displaying an array of delicate blue and green waters. Some of the colour is due to organic growth and some others due to the mineral deposits. There are splashes of red and orange from arsenic and iron sulphides, and yellow from sulphur deposits.

Norris Boardwalk Porcelain Basin Vista Porcelain Pools

The temperatures in Norris Basin have been known to be as high as 138oC, which is the highest in the Yellowstone area. Norris is also geologically younger than the other basins. This is evident from the fact that there are not large sinter (cone) formations around the geysers here. Because of its relative youth, it has undergone many rapid, observable fluctuations in activity over the past 100 years. New geysers erupting, some geysers becoming extinct, a geyser changing to a muddy pool of water, are some examples of the observed changes here. Why do these changes occur? The immediate cause is the shifting of unconsolidated gravels and clays in this basin. These shifts result in a re-routing of the channels for steam and water, causing one area to dry up or another to become wetter. The waters of this basin are acidic on the surface for a depth of about 3 meters, and revert to silica-bearing alkaline waters below that. The acidic surface water is another reason why sinter does not form in these geysers and springs.

The Norris Geyser Basin has the world's tallest active geyser, Steamboat. Steamboat Geyser can erupt upto 300 feet (90 meters) in its major eruptions, which can last anywhere between 3 to 40 mins. However, it is completely unpredictable, and the interval between major eruptions has varied between 4 days and fifty years! Its last major eruption was as recent as May 2nd, 2000. It emits powerful jets of steam with a thundering sound right after a major eruption. It does have more frequent minor eruptions upto 40 feet in height.

Other Geyser Basins of Yellowstone

Midway Boardwalk Fishing Cone Firehole River Boardwalk by Bacterial Mats
Run-off from a geyser eruption West Thumb Basin A Barren Landscape Upper Geyser Basin

Other areas within Yellowstone with a large number of thermal features include Midway Geyser Basin, Lower Geyser Basin, Biscuit Basin, and the West Thumb area of Lake Yellowstone. The former two are similar to the Upper Geyser Basin although there are unique features in each. There are more colourful hot springs in these basins than in the Upper Basin. The largest hot spring in Yellowstone, the Grand Prismatic Spring, about 370 feet in diameter, lies in the Midway Geyser Basin, and so does the Excelsior Geyser crater. This crater is a large hollow, 330 by 200 feet around and 20 feet deep. Excelsior is more of a water volcano (now dormant) rather than a geyser. When it was active in the late 1800's, its eruptions were spectacular, the water column being about 50 feet in diameter and upto 250 feet high. During its eruptions not only water, but also huge rocks were thrown out. During Excelsior's eruptions, the water level in the Firehole River flowing below it was doubled. Today, it is an intermittent hot spring discharging over 4,000 gallons of hot water per minute into the Firehole River.

Mammoth Terraces

Minerva Terrace Close-up

Mammoth Terraces feature limestone rocks dominantly, in contrast with the rhyolite rock in other parts of Yellowstone. The active terraces seen today are layers built on top of inactive ones. In fact, today there are some park facilities like a hotel, visitor centre, etc. on parts of the inactive ancient terraces. The limestone in this area is a remnant of an ancient sea that covered this region. The delicate colours visible on these terraces are mainly due to thermophiles, or heat-loving microorganisms. We will study more about these organisms in the next chapter.

Iceland

Iceland, a small island in the North Atlantic Ocean between England and Greenland, has a very volcanic geology. It has numerous colourful hot springs, and relatively few geysers, including the now dormant Great Geysir.

Iceland has an interesting geology, with hot thermal areas coexisting with frozen glaciers. For this reason it is known as the land of ice and fire.

Iceland Map

The Great Geysir is the first ever known geyser and the most famous one worldwide. Initial accounts of its eruptions date as far back as 1294, when major earthquakes shook the southern part of Iceland and the thermal area in Haukadalur valley changed to a large extent.

Old engraving of Great Geysir

The other geysers of Iceland are grouped near the Great Geysir. They are in the almost flat basin called Haukadalur, which lies parallel to a natural fault system in the earth's tectonic plate. The Icelandic government did not impose stringent restrictions protecting geysers. Tourists in the late 1800's, in their enthusiasm to see the Great Geysir erupt, used to throw rocks, peat and soap into its spout. This eventually choked off Geysir's outlet and it lies dormant now. Other popular geysers in Iceland are Stokkur (the Churn) and Smid (the Cooker) Geysers. Both are smaller versions of the Great one. Stokkur was formed in an earthquake in 1789 and became dormant for a while due to another quake in 1896. Now however, it is the largest geyser in Iceland since its channel was completely cleared in 1963.

You can have some fun trying to pronounce these curious sounding Icelandic geyser names: Sódi (the sod), Smiğur (the carpenter), Fata (the bucket), Óşerrishola (the non-draught-hole, or the rainmaker), Litli Geysir (the small Geysir) and Litli Strokkur (the little churn). Most of these are dormant geysers that have been induced to erupt with soap. Some of them erupt naturally if the air pressure gets low enough. The earthquakes of 17th and 21st June 2000 caused enormous changes in the thermal area of Iceland. Many new hot springs were formed and the volume of water flowing from existing ones also increased. Thus we see constantly how natural factors such as earthquakes, air pressure, etc. affect geothermal features. We will talk in detail about man-made factors in the chapter on Geothermal Eco Systems.


North Island, New Zealand

New Zealand Map

New Zealand lies in the South Pacific Ocean about 1,000 miles to the east of Australia. Two plates of the earth's crust meet very close to New Zealand's North Island (see Figure 2). New Zealand's two main islands, North Island and South Island are separated by Cook Strait with various smaller islands surrounding the larger islands. North Island contains hot springs and geysers, and most of the country's population.

Volcanic activity about 2,000 years ago caused the formation of a large heart-shaped lake in the centre of North Island in New Zealand. This lake, called TauponuiaTia (shortened to Taupo for good reason!), is actually a hot spring, with hot water surging and pulsating deep within it. North Island is a land of geysers, mud pots, and live volcanoes. There are various myths associated with Lake Taupo and here's one found on a National Geographic article [Nat-Geo-NZ]:

"A long time ago, back in the mists of myth, Maui, the Polynesian trickster, caught his largest fish ever here. He told his brothers, "Be gentle with this fish until it is dead. Then it will make a fine dwelling place for many." (It was a big fish.)

Alas! You know how these stories go. The brothers ignored Maui's advice and hacked and whacked into the fish, which convulsed and died.

But the heart of the fish still spasms"

The Te Puia Fault runs through a vast hot area in the North Island, known as Geyser Flat. The main geysers lie within this region. Whakarewarewa is New Zealand's most famous geothermal area. It is located just south of the city of Rotorua and northeast of Wairakei.

Kamchatka, Russia

The Kamchatka Peninsula lies in the far northeast of Russia. The geysers of Kamchatka are located in a 2.5 km stretch of the Geyser Valley, where the Geysernaya River meets the Shumnaya River. Perhaps due to the remoteness of the region, Geyser Valley was discovered as late as 1941. A female Russian scientist traveling in the area by dogsled chanced upon the valley, and then led an expedition there for further exploration.

Velikan Geyser Kamchatka Thermal Area Kamchatka Geyser Valley

In Kamchatka too, there is a "Giant" Geyser, Velikan being the Russian word for it. It jets water to a height of 40 meters and steam even higher, to hundreds of meters. Velikan sits on a 900 sq.meter platform of siliceous geserite and erupts roughly every five hours. Most of the Kamchatka geysers have such beautiful formations around them. The hillsides surrounding Geyser Valley has numerous "paint pots", or colourful mud pots. Same as in all thermal areas we have seen so far, the colouration of the thermal waters and mud is attributed to minerals in the soil as well as organic growth. Kamchatka is at a latitude where the snow is deep even in summer and winters are long. Even so, the Geyser Valley is lush with green vegetation and wild flowers, due to the warmth of the geothermal activity.

There are various views on tourism and accessibility to foreigners in Geyser Valley. According to a Kamchatka travel company, it is "open to all", but some foreign tourists who went there by special arrangement (around 1999) say that it is restricted to visitors. Apparently, the valley can be accessed only by helicopters, that too run by only one company who brings in about 200 visitors a year. The evidence from many sources concur in saying the area is indeed restricted, even to researchers from outside Russia, leave alone tourists. However, the Institute of Volcanology at Petropavlosk conducts its hydrothermal and volcano research there. Their findings, photos and maps have been published and translated, adding to the world body of research documents on geothermal activity.

Japan

Japan has a handful of natural geysers that are widely known, Atami and Miyagi Geysers among them. Beppu area is Japan's most famous hot springs resort, containing Japan's largest geyser today. In contrast to the United States protecting the thermal areas from human intervention, in Japan, you can apparently boil eggs over (or near?) a geyser! There is a picture somewhere on the Internet, of a tourist doing just that, with a covered saucepan at the end of a stick.