Supervolcanoes Around the World
What is a Supervolcano?
A volcano which erupts and throws magma and rocky particles over an area greater than 240 cubic miles (1000 cubic kilometers) is considered a supervolcano. These massive eruptions dwarf typical volcanic eruptions. It is like comparing a small shock from static electricity to a lightning bolt: Mount Vesuvius produced 100,000 cubic yards of magma per second during its massive explosion in A.D. 79. The damage from this "ordinary" volcano was legendary. If Mount Vesuvius had been a supervolcano, it would have produced 100 million cubic yards of magma per second.
Yellowstone National Park is a famous supervolcano. The last time Yellowstone erupted, 640,000 years ago, the ash blanketed an area from California to Minnesota. If Yellowstone were to erupt again, the ash would be thick enough to collapse roofs on houses in neighboring states. The loss of life would be massive: Tens of thousands of people would die from the immediate eruption and pyroclastic (lava) flow. Respiratory difficulty caused by ash in the air would kill still more people. Supervolcanoes also affect global temperature in an immediate and profound way: when Mount Tambora blew its lid in 1815, the subsequent year was called "eighteen hundred and froze to death," or "the year without summer." This event occurred during an era dubbed the "Little Ice Age," which was a period of global cooling that extended from approximately 1350-1850. Scientists have not come to a consensus of dates with regard to the Little Ice Age, and NASA currently states the event occurred between 1550-1880, with three distinct periods of cooling. The volcanic winter created by Tambora exacerbated the cooling trend for the next year.
As supervolcanoes go, Tambora was a big. The Volcanic Explosion Index (VEI) rates volcanic activity on a scale from 0-8. Hawaii's Mount Kilauea is a 0 on this index, with a constant, gentle flow of magma. Mount Vesuvius and Mount St. Helens had a VEI of 5. Tambora had a VEI of 7, the largest volcanic explosion in the modern era.
Volcanic Explosion Index (VEI)
>1 per year
> 1 per decade
>1 per century
>1 per thousand years
>1 per ten thousand years
The Most Recent Supervolcano Explosion
A sleeping volcano on an island east of Java began to wake on the morning of April 5, 1815. The first eruption was loud enough to be heard as thunder by people living over 800 miles away. Tambora's first eruption was minor compared to what happened next.
On April 10, 1815, the island of Sumbawa exploded in Indonesia. The column of ejecta shot 28 miles into the air. The mountain lost 4,100 feet of height when its top literally blew off. The volcano shot 12 cubic miles of magma into the air, and an estimated 92,000 people immediately lost their lives.
As the ash circled the earth, global temperatures plummeted. Snow fell in England and Canada in June, and frost was ever-present through the summer. Snow and ash fell into European rivers, causing Typhus outbreaks. The loss of crops in Europe also led to starvation - approximately 200,000 people died of Typhus and hunger in the year 1816, as a result of Tambora's explosion.
Supervolcanoes cause global cooling: in Tambora's case, a fine layer of sulfur dioxide gas in the stratosphere reflected the heat of the sun, which caused temperatures to plummet on the earth's surface. The sulfur dioxide gas combines with water in the upper atmosphere and forms sulfuric acid: this attacks the ozone layer, causing further damage to our planet's climate control system.
Supervolcanoes in the United States
There are several supervolcano sites in the United States - all in the western half of the country. Yellowstone in Wyoming and Montana is the most famous -and potentially dangerous - since its magma pockets have been filling since the last eruption. Other sites include:
- Long Valley Caldera, California
- La Garita Caldera, Colorado
- Valles Caldera, New Mexico
The Long Valley Caldera in California lies next to Mammoth Mountain, a popular ski resort. The supervolcano last exploded 760,000 years ago in an explosion so vast it caused the volcano's magma chamber to collapse. Ash covered all of the western United States. In 1980, an earthquake swarm started a new era of activity for this supervolcano. A dome-shaped area of land increased in height by 10 inches, and the area is monitored by the Volcano Hazards Program - a division of the United States Geological Survey. An escape route was created and named the "Mammoth Escape Route," though business owners complained that the road would scare away potential customers. The road was renamed the "Mammoth Scenic Loop," though its purpose is to serve as an emergency escape route if the volcano shows signs of imminent activity.
The La Garita Caldera produced one of the largest known eruptions on earth. Located in Colorado, the volcano deposited 1,200 cubic miles of magma approximately 27 million years ago. The caldera is 22 miles wide by 47 miles long. This supervolcano is considered extinct, but the evidence of its eruption created the Wheeler Geologic Monument and Fish Canyon Tuff.
The Valles Caldera in New Mexico had an explosion 50,000-60,000 years ago. As supervolcanoes go, it is on the small side. The area has hot springs and geothermal activity and is home to a healthy population of elk. Several films have been shot in the area, including The Missing starring Tommy Lee Jones (2003).
Supervolcanoes in the United StatesClick thumbnail to view full-size
Where is the Yellowstone Volcano?
The main caldera lies under Yellowstone Lake. Geologists Girard and Stix (2012) have identified three zones in the caldera that pose the greatest likelihood of eruption. Zone 1 is along a fault line, Zone 2 is between the Norris Geyser Basin and Mammoth (a water-driven eruption could occur here), and Zone 3 is along another fault line under Yellowstone Lake.
In 2004, the ground over Yellowstone's caldera began to rise. The elevation has been increasing by as much as 2.8 inches per year, though scientists do not believe the swelling magma pocket signals an imminent eruption. The magma pocket is 6 miles below the surface, which reduces the danger considerably. The magma chambers under Yellowstone have cyclic periods of inflation and deflation, though continuous records of geological activity were not maintained until the 1970s.
The park is monitored continuously for earthquake swarms and elevation changes. Live information about earthquake activity in the park can be found here.
Geothermal Activity in Yellowstone
Supervolcanoes in the United States
Phlegraean Fields Volcano
Activity in the Phlegraean Fields
A supervolcano exists in Naples, Italy. The Campi Flegrei, or Phlegraean Fields, is surrounded by a dense population.
The last eruption was in 1538, in an event known as the Monte Nuovo eruption. An increase in seismic activity heralded renewed activity in the area, with over 20 earthquakes felt the day before the actual eruption.The ground over the caldera rose quickly, with elevation changes of over 22 feet reported in a single night. Magma and water were ejected into the air on September 29, and a 403 foot volcanic cone (Monte Nuovo) was created within a single week. As activity died down, the new volcanic cone provided local interest. Intrigued, people came to see the newly formed volcano - on October 6, 1538, several visitors were killed when another explosion occurred. The volcano then settled and all subsequent activity has been in the form of a fumarolic vent (the emission of steam and gasses from the earth's crust).
In late 2012, significant activity was noted in the Phlegraean Fields. Swarms of earthquakes have been noted in the area, along with a lift of approximately 2.76 inches over the past year. An increase in temperature has been noted at the fumaroles. Is the Campi Flegrei gearing up for another eruption?
It is impossible to tell, though the area is continuously monitored. The International Continental Scientific Drilling Programme will drill 2.2 miles underground to monitor activity in the area. The drilling will be done near Pompei in 2013.
Supervolcano in Italy
Several supervolcanoes exist in Asia, including:
- Toba in Indonesia
- Tambora in Indonesia
- Baekdu Mountain on the border of North Korea and China
- Aira Caldera, Japan
- Kurile Lake, Russia
- Karymshina, Russia
Mount Toba, located in Indonesia, is responsible for a catastrophic eruption approximately 74,000 years ago. The largest eruption in over 2 million years, the supervolcano covered India, Pakistan, and the Persian Gulf in 3-15 feet of ash. A volcanic winter followed the eruption, lasting for approximately a decade. A thousand years of global cooling followed the incident, which nearly wiped out the human race. According to the bottleneck theory, only 3,000-10,000 individuals survived the effects of Mount Toba - the theory is disputed, however, and the reason for the remarkable lack of diversity in the human genome may lie in other causes.
Mount Tambora, previously discussed, delivered a VEI 7 eruption in 1815 and caused a volcanic winter in the following year.
Baekdu Mountain, on the border of China and North Korea, also experienced a VEI 7 eruption in the year 969. The caldera is now filled with Heaven Lake, and the central section of the mountain has been increasing in elevation due to a filling magma chamber.
The Aira caldera in Kyushu, Japan was created 22,000 years ago in a massive eruption. Japan's most active volcano, Sakurajima, is fueled by the magma chamber of the Aira caldera.
Kurile Lake is an ancient supervolcano in Russia, and exploded in 6440 B.C. with a VEI of 7. The volcano has been dormant ever since. The most active volcano in Kamchatka Penninsula, Karymsky is situated near Kurile Lake. The near-constant eruptions from the volcano have turned the large fresh-water crater lake into one of the world's largest acidic lakes.
Supervolcanoes in AsiaClick thumbnail to view full-size
Supervolcanoes in Asia
Pastos Grandes Crater
South American Supervolcanoes
The Pacana Caldera in Chile was formed approximately 4 million years ago in a VEI 8 explosion. The caldera is 43 miles wide by 22 miles long, and a few warm springs are in the area. The area is sparsely populated.
One of the best exposed calderas in the world, Cerro Galan is located in Argentina. Like the Pacana Caldera in Chile, the supervolcano is ancient and was formed 2.2 million years ago. The caldera houses the remnants of a crater lake, though the water is now restricted to the western edge of the caldera and is very salty.
In Bolivia, the Pastos Grandes Caldera was responsible for a VEI 7 eruption approximately 2.9 million years ago. A crater lake named Laguna Pastos Grandes exists in the caldera.
Supervolcanoes in South America
Supervolcano in Canada
The Bennett Lake supervolcano complex is located in British Columbia. The site is ancient and erupted 50 million years ago: the supervolcano is extinct and exists in the Coast Mountains. The caldera is located under the western portion of Bennett Lake.
Taupo: New Zealand Supervolcano
Supervolcanoes in New Zealand
Lake Taupo is one of the world's great supervolcanoes. The most recent eruption was 26,000 years ago, when a VEI 8 eruption ejected 727 cubic miles of volcanic material into the air. THe event is known as the Oruanui eruption. Taupo is currently dormant, and tends to have an eruption once every thousand years or so.
Macauley Island is located halfway between New Zealand and Tonga, and is an ancient (submerged) supervolcano. The last eruption was in approximately 4360 BC.
New Zealand Supervolcanoes
The earth is a dynamic planet, and new volcanoes (and supervolcanoes) are constantly forming. Two continent-sized piles of rock are moving toward each other under the Pacific Ocean. The colliding masses will produce a "hot spot" the size of Florida. The molten material is 1,800 miles under the earth's surface, and the collision will occur near Samoa. Fortunately, the extinction-level event won't occur for another 100 million years or so, as it takes a very long time for the masses of magma to move and create enough force for an eruption.
Questions & Answers
How do supervolcanoes form?
When magma pools below the earth's crust and is unable to break through the mantle, the pool of magma will continue to grow. This may continue until the pool of magma is sufficiently large to create a supervolcano. When the increase of pressure is enough to cause the magma to break through the mantle, an eruption will occur.