The world’s largest active volcano, Mauna Loa in Hawaii, has erupted for the first time since 1984. While it’s a giant — Mauna Loa towers over 4,100 meters but plunges another 5,000 meters into the sea down to its base — it’s not a supervolcano whose eruption could wipe out humanity.
Supervolcanoes differ from regular volcanoes by the sheer size of their magma chamber or the volume of the eruption at eruption (at least 1000 cubic kilometers). The energy that is then released is equal to that of an asteroid impact. After the material is ejected, the empty magma chamber sinks and giant calderas are formed (that of the Yellowstone supervolcano is the size of Corsica).
Supervolcano eruptions are associated with mass extinctions of species. Humanity is also said to have nearly died out during such an event; according to a controversial theory, only a few thousand of our ancestors survived the eruption of Toba some 74,000 years ago. The last supervolcano eruption was 26,500 years ago near Lake Taupo in New Zealand.
It is not known exactly how many supervolcanoes there are. They are often not as easy to identify as volcanoes because they do not necessarily form a cone. There are currently about 20 candidates, here is a selection of seven supervolcanoes.
The volcanic complex on the Yellowstone River in the US state of Wyoming is 17 million years old and lies above a hot spot – a zone in which hot material from the earth’s mantle rises into the earth’s crust. The magma chamber at a depth of 45 to 20 kilometers is enormous: the contents could fill the Grand Canyon eleven times.
The last major eruption occurred 640,000 years ago. At that time, a giant crater was formed, on which Yellowstone Park is located today. The next big eruption is coming, geologists think. In this science, which reckons with very long time periods, “expected” means within a few thousand years. The US Geological Survey estimates the probability of a major eruption to be 1 in 700,000 per year.
In the north of the Indonesian island of Sumatra is the largest crater lake in the world, Lake Toba. It originated about 74,000 years ago when the supervolcano Toba erupted – believed to be the largest eruption in the past two million years. At that time, about 2,800 cubic kilometers of volcanic material was probably ejected up to 80 kilometers into the atmosphere. The ash covered an area of four million square kilometers and even reached India. The result was years of cooling of the climate by several degrees.
This outbreak may have pushed our ancestors to the brink of extinction: DNA research points to a genetic bottleneck in this period. Since this mega-eruption, there have been several smaller eruptions, but not more recently. However, there are active steam vents on the north side of the caldera and the region is very seismically active: the last major earthquakes occurred only in 2004/2005.
Also, Lake Taupo in New Zealand’s North Island hides a super volcano that lurks beneath the lake. The last major eruption was 26,500 years ago. This so-called Oruanui eruption threw an estimated 1200 cubic kilometers of material into the atmosphere. Since then there have been 28 other eruptions, but they were not as strong.
The Taupo last erupted 1830 years ago. Although the amount ejected was “only” 50 to 60 cubic kilometers, it was probably the largest eruption in the past 5,000 years. All of New Zealand was covered in ash; exceptionally red sunsets were observed in China and the Roman Empire.
The southern Italian metropolis of Naples is in dangerous territory: the “Campi Flegrei”, the Phlegraean Fields (from ancient Greek phlego “to burn”) begin right on the western edge of the city, the volcanic cone of Mount Vesuvius rises to the east of the city and a volcanic system extends to the south of the island of Ischia. The magma chamber beneath the Phlegraean Fields, discovered in 2008, is connected to that of Mount Vesuvius.
The last eruption, although not very strong, had occurred in 1538. Possibly ejected up to 500 cubic kilometers of material.
The ground above the Campi Flegrei rises and falls all the time. Geologists are watching the movements closely to anticipate a possible eruption of the supervolcano. Currently, the rise has slowed to half an inch per month, but that doesn’t mean everything is safe. On the other hand, an increase does not have to lead to a catastrophe: in the 1980s, the area around the Neapolitan port city of Pozzuoli rose more than eight feet – without an eruption following.
In the border triangle of Argentina, Bolivia and Chile, there are several calderas under which supervolcanoes may lie dormant. The Vilama Caldera is definitely a super volcano, having formed 8.4 million years ago during one of the largest known volcanic eruptions. An estimated 2,000 cubic kilometers of gases, magma and volcanic ash were released into the atmosphere.
Rising on the edge of the Vilama Caldera, the Uturuncu was previously considered nearly extinct; the last eruption of the 6000 meter high volcano was almost 300,000 years ago. However, new observations show that a circular area ten times the size of Lake Constance around Uturuncu is rising by two centimeters per year. This and a series of smaller earthquakes suggest magma is entering a reservoir 15 to 20 kilometers below the volcano.
The 2,200 square kilometer Lazufre area on the Chilean-Argentine border has been bulging since 1998 at a rate of four centimeters per year. To date, 40 volcanoes have been identified in the region, some as large as Mount Vesuvius. The magma bubble under the Lazufre area is said to be ten kilometers deep.
In particular, geologists are keeping an eye on Lastarria, one of the region’s few volcanoes to have been emitting large amounts of sulfur for centuries. The researchers see it as a kind of valve for the lower magma chamber.
In southwestern Colorado is La Garita, a massive caldera stretching 22 miles by 47 miles into the San Juan Mountains. So it has an unusually elongated shape for a caldera. What is considered the strongest eruption of the entire Cenozoic Era (Cenozoic Era, the last 66 million years) occurred here 26 to 28 million years ago.
The eruption ejected an estimated 5,000 cubic kilometers of material — almost twice as much as when Toba erupted 74,000 years ago. This massive explosion was followed by seven other major eruptions over the next 1.5 million years.
Source: Blick
I am Ross William, a passionate and experienced news writer with more than four years of experience in the writing industry. I have been working as an author for 24 Instant News Reporters covering the Trending section. With a keen eye for detail, I am able to find stories that capture people’s interest and help them stay informed.
