- Not to be confused with Volcano, California.
Volcanoes come in many shapes and sizes, and their eruptions vary hugely in both frequency and intensity. Many volcanoes are tourist attractions and are worth a visit provided you take due care, in particular keeping a safe distance from eruptions.
Volcanic eruptions are not all that common — a few dozen a year, worldwide — and are extremely dangerous. The worst of them cause complete devastation over wide areas, sometimes with a large death toll.
According to the Smithsonian Global Volcanism Program, the major volcano monitoring organization based in Washington, DC, volcanoes can be classified as follows:
- active if
- it has erupted within the last 10,000 years (recently in geological terms)
- or it shows considerable activity such as hot springs, fumes, and earthquakes
- dormant (French for sleeping) if it is active but not currently erupting
- extinct if it is no longer active
Other organizations generally use the same terms, but may have somewhat different definitions. These definitions are not precise; dormant volcanoes sometimes erupt, and it is not unknown for supposedly extinct volcanoes to come back to life.
There are hundreds of active volcanoes around the world, but many more that are dormant or extinct. One can still appreciate the awesome power of nature from these volcanoes, without the hazards that go with active ones.
- Decade Volcanoes. A group of 16 active volcanoes selected by scientists as particularly worthy of study because they both have a history of large eruptions and are located near populous areas. These may be the most dangerous volcanoes on Earth in terms of potential to create large disasters.
Perhaps the best-known type of volcano is the stratovolcano which is built up from multiple layers of ash and lava over centuries, giving a conical shape. Several of the world's most famous volcanoes, such as Fuji, Krakatoa, Vesuvius and Kilimanjaro, are of this type. Filipino tourist literature claims their Mayon Volcano has the world's most perfect cone.
A somewhat less common type is a shield volcano, formed when the lava is less viscous and therefore spreads out much further. Most of Hawaii's volcanoes are of this type.
There is a scale for the force of eruptions called the Volcanic Explosivity Index or VEI; the main factor is the volume of ejecta, the amount of material spewed out. The scale is mostly logarithmic; a VEI-5 eruption produces at least 1 km3 of ejecta, VEI-6 10 km3, VEI-7 100 km3, and VEI-8 1000 km3.
Really large eruptions are quite rare. The 20th century had seven eruptions of VEI-5 or VEI-6 and hundreds of smaller ones, but none of VEI-7 or above. The most recent VEI-7 events were Lake Taupo (New Zealand) in 180 CE, Ilopango (El Salvador) around 431, Mount Paektu (on the Korean-Chinese border) around 946, possibly Mount Rinjani (Indonesia) in 1257, and Mount Tambora (Indonesia) in 1815. As for VEI-8, there has not been such an event in recorded history; the most recent was at Lake Taupo about 26,000 years ago.
The Tambora eruption of 1815 put out 160 cubic km (38 cubic miles) of ejecta, including enough dust and ash to cause "the year without a summer", widespread crop failure and some famine as far away as the US and Europe. Said "year without a summer" led the German Karl Drais to invent a "walking machine" which is today considered the first ancestor of the modern bicycle.
Some eruptions have complications. The 1883 eruption of Krakatoa was rated only 6 on the VEI scale, but the explosions were absolutely enormous — heard several thousand miles away and estimated to be equivalent to 200 megatons of TNT — mainly because a huge amount of seawater was instantly turned to steam on contact with superheated magma.
Supervolcanoes are the largest volcanoes on Earth, but are not easily recognizable as such. Many are so big that, for many years, even geologists did not appreciate that these features were volcanoes in their own right.
|“||Volcanoes form mountains; supervolcanoes erase them. Volcanoes kill plants and animals for miles around; supervolcanoes threaten whole species with extinction by changing the climate across the entire planet.||”|
Supervolcanoes are generally in the form of large calderas (Spanish for "cauldron"), which are giant volcanic depressions formed either by large explosive eruptions or quiet long-term drainage of magma. They often have associated lava flows or domes, and in many cases there are smaller volcanoes within the caldera. Many of the calderas are now lakes, and sometimes the smaller volcanoes are islands in the lake.
Examples of supervolcanoes include Yellowstone in the United States, Lake Toba and Mount Tambora in Indonesia, the Phelgraean Fields near Naples in Italy, and Lake Taupo in New Zealand. Most supervolcanoes have undergone unimaginably huge eruptions (VEI-7 or 8) in the geologic past; these are what created the huge caldera. However, such eruptions are tens or hundreds of thousands of years apart. There is no reason to worry that Yellowstone will explode during your visit.
Throughout volcanic areas of the world, one may also encounter geothermal areas. These places are often, but not always, associated with volcanic activity. Hot springs, geysers, mud pools and fumaroles (steam/gas vents) are common scenic features in geothermal areas, and hot springs can be great places to take a dip. Countries such as Japan, South Korea, Taiwan and Iceland are especially famous for hot spring baths. Geothermal areas are also an environmentally friendly source of energy, and Iceland takes advantage of this very well.
Yellowstone National Park is probably the best known example of a geothermal area, as molten magma lies not far beneath its 640,000-year-old caldera. New Zealand, with its volcanoes in the North Island, is also known for extensive geothermal areas, with Rotorua perhaps being the best known one. Geysir in Iceland, which is the namesake for all geysirs in the world, is another famous geothermal region. The Maori people of New Zealand, who traditionally cooked their food by burying it underground with heated rocks (known as a hangi), often make use of the geothermal heat instead if they live in a geothermally active area. Similarly, Iceland has a tradition of baking rye bread underground using the geothermal heat.
Scientists can make predictions about volcanic activity, and those predictions are good enough to make it essential for travellers to check local media for current warnings when planning any trip to a volcanic area. However, the problem is complex so predictions are generally not precise and sometimes not entirely reliable.
Volcanic activity is often associated with earthquakes, and those have another whole set of hazards.
Public safety authorities may order hazard areas evacuated and visitors should certainly follow such advice. However, the onset of some volcanic events can be quite sudden, and in those cases there might be considerable damage before the government can react. Also, authorities may be slow to act in much of the world since evacuations are disruptive, expensive and sometimes controversial. If you are near a volcano that begins to act restless — perhaps earth tremors or expelling steam or dust — it may be wise to leave the area before any evacuation order.
Volcanoes are complex and can be quite different from each other, so for most of them it is a good idea to have an expert guide who knows the particular mountain you want to visit. If you want to go anywhere near an erupting volcano, then a guide is absolutely essential. On the other hand, climbing some volcanoes without a guide is reasonable; for example Mount Fuji has not erupted since 1708, scientists are not issuing warnings, and there are well-marked trails.
Good footwear is essential since many volcanic rocks have sharp edges and some are hot as well. A sturdy pair of hiking boots are the usual choice, but some people go further and wear construction boots with a layer of steel in the soles.
An erupting volcano is extremely dangerous. Unless you have an excellent reason for going near one, the best advice is to stay away and watch it from a considerable distance, or even from the safety of your home or hotel on the TV news.
Volcano hazard zones can extend for dozens of kilometers, and there are multiple hazards:
- Lava is molten rock spewing forth from the volcano. In addition to the direct danger, a large lava flow radiates enough heat to ignite vegetation and kill animals at a considerable distance.
- Pyroclastic flows are streams of red-hot ash and debris that rush downslope from their source vents, incinerating anything flammable in their path. They can reach temperatures up to 800°C (almost 1500°F) and travel at up to 150 km/h (93 mph).
- Volcanic bombs are rocks thrown upward by eruptions; they can be thrown thousands of meters high and may land dozens of km away. They range from pebbles to the size of a house, but the most dangerous ones are in the size range between an egg and a soccer ball, big enough to kill or cause serious injuries but light enough to often be thrown long distances.
- Jökulhlaups are floods, which can be caused by the volcano melting parts of a glacier. On Iceland there have been peak discharges in the order of magnitude of floods of the Amazon River. Bridges downstream from Vatnajökull used to get destroyed on a regular basis. Volcanoes can also cause floods when a crater wall collapses releasing the lake within, by melting snow that is not part of a glacier, or by blocking rivers.
- Steam is dangerous, perhaps just scalding but in some cases (Krakatoa or some geysers) explosive. In many cases, hot water or hot mud are nearly as hazardous.
- Lethal gasses are gasses from eruptions, typically carbon dioxide and sulphur dioxide. Often, but not always, the stink of sulphurous compounds provides a warning; avoid areas with a rotten egg smell. Also try to stay upwind of any vents releasing gasses; assume any vent with steam may also have nastier gasses. Walking toward a vent, keep the wind at your back; walking away, keep it in your face.
- Vog or volcanic smog is a nasty combination of water droplets with dissolved gasses, possibly plus volcanic dust. Since SO2 in water become sulphurous acid, this is highly irritating to eyes and throat. In high concentrations or for vulnerable people — asthma, heart or lung disease, children, pregnant women, the elderly, etc. — it can be very dangerous. If you are exposed, a face mask gives some protection and drinking lots of water will soothe the throat.
Staying on high ground when observing a volcano gives you a better view and reduces several hazards. The dangerous gasses are heavier than air and collect in low-lying areas, and lava, pyroclastic flows and floods all tend to follow the contours of the land. A combination of distance and altitude also reduces the risk from volcanic bombs. Often the best place to observe is from high on the other side of a valley, well away from the volcano. Bring binoculars and a telephoto lens.
Ashfall, volcanic mudflows, and the effects of earthquakes can extend for hundreds of kilometers away from the volcano. The most famous victim of ashfall was the Roman city of Pompeii, buried in 79 CE by Mount Vesuvius. Those two were only about 8 km (5 miles) apart, but ash can also be transported by air in vast quantities over a huge area. The enormous (VEI-8) prehistoric eruption of Yellowstone spread a layer of ash, close to two meters thick in places, over most of the US and parts of Canada and Mexico.
Volcanic ash tends to stop aircraft and vehicle engines, so transportation in the area may be restricted or disrupted. An eruption in Iceland in 2010 shut down airports in Europe, more than 1000 km away. The 2020 eruption of Taal Volcano in the Philippines shut down Manila airport, about 50 km away, for several days.
When a volcano is dormant, you can go fairly close to it and still be safe, but even dormant volcanoes are hazardous. Lava flows can still be hot for years after an eruption and only a thin crust of rock may be covering them. Old lava flows can be sharp as broken glass, so you should wear hiking boots or very thick shoes. To add to these dangers, lethal gases may be seeping out of vents near the volcano.
A lahar is like an avalanche or flash flood of old ash from an eruption that becomes mobile by rainfall, earthquake or a collapsing crater lake. They can occur long after eruptions, travel many kilometers, and be devastating. While there are often some warning signs before eruptions, lahars can have no warning. Watch out for possible lahars when there are heavy rains.
Geothermal areas can have hazards similar to those of volcanoes due to geological mechanisms. Hot springs and mud pools can be dangerous due to heat, acidity, or poison, so do not go near these areas unless you know for sure that they are totally safe. Geysers are a common feature of major geothermal areas, and can erupt hot water or mud unexpectedly.
Landslides are also common in geothermal areas, as even volcanic rock can become weakened over time. Acidic fumes can seep out of fumaroles (steam/gas vents) or hot springs. Noxious gases can also be encountered coming out of holes in the ground, and the gases can reach dangerous levels in enclosed spaces like caves, manholes, or pool enclosures. Carbon dioxide, which is a byproduct of volcanic activity, is known for going into enclosed spaces and it can kill swiftly with little or no warning.
A selection of some of the more active and/or better known volcanoes in the world today. Some of these can still be explored from up close.
- 1 Mount Cameroon (Mongo ma Ndemi). The only volcano outside of Europe to have records of an eruption before the Common Era in 5 BC. It remains active today: its most recent eruption was in 2012. Near the city of Buea.
- 2 Mount Kilimanjaro. This peak in Tanzania is Africa's tallest at 5895 m (19,340 ft). It has a series of concentric summit craters apparently less than 10,000 years old and may have last erupted less than 2000 years ago. The name Kilimanjaro means "shining mountain" in Swahili, no doubt due to the once-extensive glaciers which are unfortunately disappearing rapidly each year.
- 3 Mount Nyiragongo. In Virunga National Park in the far eastern D.R. Congo, near Goma and the Rwandan border. One of just four volcanoes in the world with a persistent lava lake, the others being Erta Ale (Ethiopia), Kilauea (Hawaii), and Mount Erebus (Antarctica). The volcano is usually accessed by overnight hike (8–10 hr up first day, hike down the following morning), with the night spent in tents on the rim of the caldera with stunning views of the lava lake and the surrounding region. Unfortunately, it is located in a conflict zone and access is occasionally blocked due to the presence of rebels & criminal gangs. It is a Decade Volcano.
- 4 Ol Doinyo Lengai ("Mountain of God" in the Masai tongue). In Ngorongoro Conservation Area in Tanzania, this is the only volcano on Earth that erupts natrocarbonatite lava. This type of lava emerges black, cools to grey, and oxidizes to white.
- 5 Volcanoes National Park. This park in Rwanda is famous as the home of mountain gorillas.
- 6 Barren Island. This is the only volcano in the Andaman Islands and the only active volcano in India. Day trips can be arranged from Port Blair. No additional permit is required to visit the island, but it is not possible to land on the island, only to view it from the boat.
With 167 known active volcanoes, Indonesia is the world's most volcanic country by far.
- 7 Krakatoa. This is an island in West Java province with several volcanoes on it which produced multiple explosions in 1883. The largest is estimated to have been equivalent to 200 megatons of TNT, about four times the largest H-bomb ever tested, and the sound was heard 5,000 km (3,100 mi) away. The dust cloud had worldwide effects; global temperatures dipped by over a degree. This was a VEI-6 event.
- 8 Mount Batur (Bali). A very accessible active volcano which takes just 2 hours to climb.
- 9 Mount Agung. A highly visible volcano in the interior of Bali. "Agung" means "great" in Indonesian. The volcano is considered quite sacred by Balinese people, and its slopes are home to the beautiful temple complex of Besakih. Its last eruption, in 1963, was quite devastating.
- 10 Mount Bromo (East Java). Known for its unreal scenery, especially with Mount Semeru, Indonesia's third highest active volcano nearby.
- 11 Mount Merapi (Central Java). Perhaps Indonesia's single most active volcano (no mean feat). It looms large over the major cities of Yogyakarta and Solo, and the very popular temples of Borobudur and Prambanan. Merapi has erupted 68 times since formal record-keeping began in the 16th century. Its eruption on May 11, 2018, prompted the evacuation of areas within a 5-kilometre (3.1 mi) radius of the volcano, and the closure of the Yogyakarta airport. It is a Decade Volcano.
- 12 Mount Rinjani (Lombok). Indonesia's second highest volcano with a stunning crater lake. It's a two-day trek to the crater rim.
- 13 Mount Tambora. This volcano in Sumbawa is one for the truly adventurous. Only about 50 visitors a year make it to this very remote volcano. In 1814 Tambora was 4,200 m (13,800 ft) high. It erupted with such force (VEI-7) the following year that 1,400 m (4,600 ft) was lost from its top. That was much the largest eruption in recent history, about ten times more powerful than the Krakatoa eruption a few decades later. It put enough dust and ash into the atmosphere to cause a "volcanic winter" that affected most of the Northern hemisphere; livestock deaths and crop failures caused the worst famine of the century.
- 14 Mount Aso. This is on the island of Kyushu; it is one of the largest active volcanoes in the world with the largest caldera.
- 15 Mount Fuji. Located in central Japan near Tokyo, this is Japan's highest and most beautiful volcano. It is also the most climbed mountain in the world because so many people climb it to view the sunrise from its summit crater.
- 16 Sakurajima. This is an active volcano just outside of Kagoshima.
The Philippine Institute of Volcanology and Seismology lists 23 volcanoes as "active"; 21 of those have erupted in the last 600 years. Another 25 are listed as "potentially active" and 355 as "inactive".
- 17 Mayon Volcano (within Albay). Often described as the world's most perfect volcano cone, Mayon had a fatal eruption in 1993.
- 18 Taal Volcano (in Batangas province). This is a complex volcano system described as a "lake in a volcano in a lake" and one of the most picturesque landscapes in the Philippines. Often reached via the nearby city of Tagaytay, where package tours to the volcano are offered. It is the Philippines's second most active volcano, with history of destructive eruptions and one of the "Decade Volcanoes". An eruption in early 2020 forced the evacuation of several towns.
- 19 Mount Apo (near Davao in Mindanao). This dormant stratovolcano is the highest peak in the Philippines at 2,954 meters (9,692 ft).
- Kamchatka, Russia's largest Pacific peninsula, has several active volcanoes and some hot springs and geysers
- 20 El Teide. This volcano in Tenerife is the highest active volcano in the Canary Islands at 3715 m (12,188 ft). A flank vent at El Teide was observed erupting by Christopher Columbus and his crew in 1492. El Tiede is one of the Decade Volcanoes. It is in Teide National Park, a UNESCO World Heritage Site.
- 21 Nisyros. This island in the Greek Dodecanese islands is the top of a volcano, mildly active with smoking fumaroles. It is possible to walk into the crater floor for a closer look.
- 22 Santorini. This island in the Aegean Sea is the largest of a ring of islands around an ancient caldera, and probably Greece's most famous volcano. It had a VEI-7 eruption around 1600 BCE. Some historians suggest the associated tsunami and earthquakes destroyed the Minoan civilization on nearby Crete, or that the devastation of these islands is the origin of the Atlantis myth, but both those theories are quite controversial.
The volcano is still active, for it last erupted in 1950 out of Nea Kameni ("New Burnt" in Greek), an island made up of lava flows in the middle of the caldera bay.
Iceland has many active volcanoes, among them Hekla, Katla and Askja. In medieval times Hekla was thought to be a gateway to Hell. It has had five eruptions since 1947 (the last being in 2000), and is regarded as unpredictable. A volcano below the Eyjafjallajökull glacier famously disrupted European air travel for days with an ash cloud released during an eruption in the year 2010.
- 23 Vesuvius. This is a dormant volcano near Naples. It has not been smoking since it last erupted in 1944, but it is still very closely and carefully monitored because of its seriously hazardous proximity to that city, which is southern Italy's most populous. It is famous for its eruption in 79 CE, which buried the Roman cities of Pompeii and Herculaneum under layers of pumice, ash and lava fragments.
- 25 Stromboli. This volcano in the Aeolian Islands has been in near continuous activity since at least the time of the Ancient Greeks and has been billed as the "Lighthouse of the Mediterranean".
Both Etna and Vesuvius are Decade Volcanoes.
North America and Caribbean
- The Aleutian Islands of Alaska are volcanic in origin and have several active volcanoes.
- 26 Mount Baker (Washington State). This is one of the five major stratovolcanoes in the area that have produced over 200 eruptions in the last 12,000 years.
- 27 Mount St. Helens (Washington State). This volcano is famous for an eruption in 1980 that was a VEI-5 event, one of the largest of the century. Since late 2004, it has been erupting once again, but not nearly as violently – this time, a new lava dome is slowly being extruded in its crater.
- 28 Mount Hood (Oregon). At 11,239 ft (3,426 m) this is the highest mountain in the state of Oregon and a major outdoor recreation area. Located about 50 mi (80 km) east-southeast of Portland, the mountain is visible from the city on clear days and usually forms the backdrop for the Portland skyline in postcards and photographs of the city.
- 29 Mount Rainier (Washington State). At 14,410 ft (4,390 m), this is the most prominent peak in the Cascade Range, about twice the height of the adjacent mountains. The volcano, which last erupted approximately 150 years ago, is encased in over 35 sq mi (91 km2) of snow and ice. It is the only Decade Volcano in the continental United States, considered quite dangerous because it is only about 50 km (30 miles) from Seattle.
- 30 Mount Redoubt (about 180 km (110 mi) southwest of Anchorage). The largest active volcano in mainland Alaska.
- 31 Popocatepetl (near Mexico City). Popocatepetl often has a volcanic plume above its crater which is 5,450 m (17,880 ft) high. The name means "smoking mountain" in the native Nahuatl language.
- 32 Mount Pelée. An eruption here in 1902 wiped out the town of Saint-Pierre (Martinique). Attractions of the rebuilt town today include a volcano museum and wreck diving around the many ships sunk by that eruption.
- 33 Soufrière Hills. Soufriere Hills on Montserrat, previously considered dormant, began erupting again in 1995, forcing the closure of the southern half of the island (including its capital and airport in 1997). It is still active, though mostly a nuisance seeping lava and spewing ash into the air.
Canada has no active volcanoes and is thought to have had only about 50 eruptions in the past 10,000 years. However, the Canadian Rockies include many dormant volcanoes; geologically they are part of the same system that produces active volcanoes in Washington, Oregon and Alaska.
South and Central America
- 34 Cotopaxi (in Ecuador). One of South America's most spectacular volcanoes.
- Arenal in Costa Rica, the youngest volcano of the country. Its eruptions were frequent until 2010, but now it is calm.
- Volcan de Fuego and Volcan Pacaya in Guatemala, near Antigua Guatemala.
- Volcan Atitlan, Volcan San Pedro and Volcan Toliman in Guatemala, on the southern shores of Lake Atitlán.
- Volcan Láscar in the Atacama Region of northern Chile.
- The Volcanoes of Concepción (active) and Maderas (dormant) that form the island of Ometepe , Nicaragua
The entire Hawaiian island chain is volcanic in origin. Most of the volcanoes are of the shield volcano type, spread out rather than sharply conical
- 36 Kilauea (Big Island). This volcano has been erupting continuously out of its flank vent, known as Pu'u O'o ("Hill of the O'o bird" in the native Hawai'ian language) since 1983. You can normally peer safely into its magma chamber from an observation point a couple of miles away in Hawaii Volcanoes National Park after nightfall.
- 37 Mauna Loa (Big Island). Hawaii's highest historically active volcano, topped by the Moku'aweoeo Caldera. It is also the largest volcano by volume in the world. Don't be fooled by its gentle slopes - with its highest point at 4170m/13,683 ft), the altitude can be hard on inexperienced hikers and its summit is often covered in snow during the winter. It is Hawaii's only Decade Volcano.
- Mauna Kea (Big Island). This is the highest volcano in Hawaii at 4205 m (13,796 ft), and is pockmarked with cinder cones. Its high elevation is a magnet for astronomers with their giant telescope facilities, and even skiers.
- Hale'akala ("House of the sun" in Hawai'ian) (Maui). This is the tallest volcano on the island of Maui, and is renowned for its erosional crater and the cinder cones nestled inside.
- 38 Tongariro National Park. This park has three active volcanoes, Mount Ruapehu, Mount Tongariro and Mount Ngauruhoe. Ruapehu, New Zealand's highest volcano, has a crater lake that forms and fills when the volcano is not erupting.
- 39 White Island. is a volcanic island in the Bay of Plenty, southeast of Auckland, and the most active volcano in New Zealand. Tours used to go to the island, until an eruption in 2019 killed a large number of visitors.
- 40 Taupo. This town is located next to New Zealand's largest lake, which is the caldera of a supervolcano. It had a VEI-7 eruption in 180 CE that produced red skies as far away as Rome and China. Around 25,000 BCE it had a VEI-8 blast.
Papua New Guinea
- 41 Mount Tavurvur. This is a very active volcano right next to the city of Rabaul on the island of New Britain. Much of the town was destroyed in a 1994 eruption. It last erupted in 2006, shattering windows up to 12 km (7.5 mi) away and sending an ash plume 18,000 m (59,000 ft) into the stratosphere.
- Mount Ulawun is another very active volcano on New Britain. It is New Guinea's only Decade Volcano.
Over 130 volcanoes have been discovered in the frozen wastelands of Antarctica, and with many erupting underneath the dense ice sheets they are not particularly practical to visit.
- 42 Mount Erebus. At 3,794 metres (12,448 ft) Mount Erebus is the highest and most active volcano on the continent. There used to be aerial tours over the volcano from New Zealand until a fateful crash in 1979.
The following travel agencies specialize in volcano tourism.
- Volcano Adventure Indonesia [dead link], Sukapura, Indonesia, tel. +62-335-581439, +62-81319090225, . Tours to Mount Bromo and elsewhere in Indonesia.
- VolcanoDiscovery, Germany, tel. +49 2241-2080175, +30 2107522310. This tour operator specializes in international volcanoes and one of its most important programs is for Indonesian volcanoes. The tours are trekking & photography tours with small groups and an intensive personal service. The tours are usually about 7–14 days.