Supervolcanoes 101 | National Geographic

National Geographic

6 Aug 201803:41

Summary

TLDRSupervolcanoes, Earth's most powerful and complex volcanic phenomena, are marked by calderas and can undergo explosive eruptions, reaching magnitude eight on the Volcanic Explosivity Index. They experience a life cycle of pressure build-up, supereruption, and resurgence, with the latter stage often leading to the creation of natural beauty and life renewal. The Campi Flegrei in Italy and the Taupo in New Zealand exemplify this cycle, with the latter's last eruption expelling enough material for half a million Great Pyramids of Giza.

Takeaways

🌋 Supervolcanoes are the most powerful and complex type of volcano, capable of the most violent eruptions.
🌍 There are around 20 supervolcanoes worldwide, often characterized by large depressions called calderas.
🔥 They erupt at a magnitude of eight on the Volcanic Explosivity Index, which is the highest and most violent classification.
🔥🔧 The life cycle of a supervolcano includes three major stages: magma accumulation, supereruption, and resurgence.
🌡️ The first stage involves a hotspot, a pocket of trapped magma under the Earth's crust, which builds pressure and can cause the ground to rise.
📈 The Campi Flegrei in Italy has demonstrated significant ground uplift due to magma accumulation in recent decades.
💥 A supereruption occurs when the pressure in the magma reservoir reaches a critical point, ejecting vast amounts of tephra into the atmosphere.
🌋💨 The most recent supereruption was at Taupo in New Zealand, which ejected about 1,100 cubic kilometers of tephra.
🕰️ After a supereruption, a supervolcano enters the resurgence stage, where the magma reservoir collapses, forming a caldera.
🏞️ The Yellowstone Caldera is an example of a supervolcano in the resurgence stage, with a lake and geothermal features formed post-eruption.
🌿 Supervolcanoes, despite their destructive power, can lead to the creation of new ecosystems and natural beauty after their eruptions.

Q & A

What are supervolcanoes?
-Supervolcanoes are the most violent and complex class of volcanoes, characterized by large depressions in the ground called calderas, located above multiple openings in the Earth's crust.
How many supervolcanoes are there on Earth?
-There are around 20 supervolcanoes scattered across the planet.
What is the Volcanic Explosivity Index and how does it classify supervolcano eruptions?
-The Volcanic Explosivity Index is a scale that measures the explosivity of volcanic eruptions. Supervolcanoes are classified at a magnitude of eight, which is the highest and most violent classification on the index.
What are the three major stages in the life cycle of a supervolcano?
-The three major stages in the life cycle of a supervolcano are the surge of trapped magma, a supereruption, and a resurgence.
What is a hotspot in the context of supervolcanoes?
-A hotspot is a pocket of magma trapped under the Earth's crust that is fed by a pipeline deep into Earth's molten interior. It grows and builds pressure underground.
How does the ground react when a hotspot forms under it?
-When a hotspot forms under the ground, it causes the crust above to be pushed upward due to the buildup of pressure from the trapped magma.
What is the Campi Flegrei supervolcano and what has it done in recent times?
-The Campi Flegrei is a supervolcano on the west coast of Italy that has pushed the ground up several times over the past few decades, with one instance causing the ground to swell up to six and a half feet within two years.
What happens during a supereruption?
-During a supereruption, the buildup of pressure in a magma reservoir reaches a critical mass and explodes, sending over 1,000 cubic kilometers of tephra, or ash and rocky material, into the sky.
When was the most recent supereruption and which supervolcano was responsible?
-The most recent supereruption occurred approximately 26,000 years ago at the supervolcano Taupo in New Zealand.
What is the Taupo supervolcano's supereruption estimated to have ejected?
-The Taupo supervolcano ejected about 1,100 cubic kilometers of tephra into the air during its supereruption, which is enough material to constitute nearly half a million Great Pyramids of Giza.
What is the resurgence stage of a supervolcano and what happens during this stage?
-The resurgence stage is when a supervolcano's magma reservoir collapses after a supereruption, forming a caldera. Freshwater collects in the caldera to form a lake, plants and wildlife return, and geothermal features emerge.
What is the Yellowstone Caldera and what stage is it currently in?
-The Yellowstone Caldera is a supervolcano in the United States that is currently in the resurgence stage after a supereruption occurred about 640,000 years ago.
How do supervolcanoes contribute to natural beauty after their cataclysmic events?
-Supervolcanoes create unparalleled natural beauty by forming unique geological features, lakes, and supporting the return of plant and wildlife life after their destructive eruptions.

Outlines

00:00

🌋 Introduction to Supervolcanoes

Supervolcanoes are the most powerful and complex type of volcano, capable of both immense destruction and fostering new life. There are around 20 such volcanoes globally, typically marked by large depressions known as calderas, which are positioned above multiple points where the Earth's crust is thin. They are categorized as the most violent, with eruptions reaching magnitude eight on the Volcanic Explosivity Index. The life cycle of a supervolcano includes three stages: the buildup of trapped magma, a supereruption, and a resurgence. The first stage involves a magma reservoir, or hotspot, that accumulates pressure beneath the crust, sometimes causing the ground to rise significantly, as seen at Campi Flegrei in Italy. The second stage is characterized by a supereruption, where immense pressure leads to an explosion that can send over 1,000 cubic kilometers of tephra into the atmosphere, as exemplified by the Taupo eruption in New Zealand 26,000 years ago. The final stage, resurgence, sees the magma reservoir collapse, forming a caldera, which can eventually fill with water and support new ecosystems, as observed at the Yellowstone Caldera.

Mindmap

Keywords

💡Supervolcanoes

Supervolcanoes are a class of volcanoes known for their immense size and potential for catastrophic eruptions. They are characterized by large calderas, which are depressions in the ground formed by the collapse of the magma chamber. The video emphasizes their destructive power, yet also notes their role in creating conditions for new life. For instance, the supervolcano Campi Flegrei in Italy has caused the ground to rise significantly due to trapped magma, illustrating the dynamic nature of these geological features.

💡Calderas

A caldera is a large volcanic depression typically formed by the collapse of a volcanic edifice following a massive eruption. Calderas are a key feature of supervolcanoes, as they mark the location where immense amounts of magma have been expelled. The script mentions that supervolcanoes are usually characterized by these large depressions, which are the result of the earth's crust collapsing after a supereruption.

💡Magma

Magma is molten rock material found beneath the Earth's surface. In the context of the video, magma plays a central role in the life cycle of supervolcanoes. It accumulates in a hotspot, a reservoir beneath the crust, and builds pressure until it can no longer be contained, leading to a supereruption. The video describes how the accumulation of magma at Campi Flegrei caused the ground to swell, demonstrating the power of this subterranean force.

💡Volcanic Explosivity Index (VEI)

The Volcanic Explosivity Index is a scale used to measure the strength of volcanic eruptions based on the volume of material ejected and the explosiveness. The video highlights that supervolcanoes are classified at the highest magnitude of eight on this index, indicating their potential for the most violent eruptions. This scale helps to contextualize the immense scale of destruction that supervolcanoes can unleash.

💡Supereruption

A supereruption is a massive volcanic eruption that releases an extraordinary amount of material, typically over 1,000 cubic kilometers. The video describes the supereruption stage of a supervolcano's life cycle, where the pressure from the trapped magma reaches a critical point and results in an explosive release. The Taupo eruption in New Zealand, which ejected about 1,100 cubic kilometers of tephra, is cited as an example of such a catastrophic event.

💡Tephra

Tephra is a collective term for the fragments of rock and ash ejected during a volcanic eruption. The video mentions that a supereruption can send over 1,000 cubic kilometers of tephra into the sky, which can have global climatic impacts and create vast deposits of material. The Taupo eruption is highlighted as an example where the ejected tephra was enough to construct nearly half a million Great Pyramids of Giza.

💡Resurgence

Resurgence is the final stage in the life cycle of a supervolcano, following a supereruption. It involves the collapse of the magma reservoir, leading to the formation of a caldera. The video explains that after the Yellowstone supervolcano's last supereruption about 640,000 years ago, the area entered a stage of resurgence, where the caldera filled with water, life returned, and geothermal features developed, showcasing the potential for renewal after such devastating events.

💡Hotspot

A hotspot is a region of intense heat within the Earth's mantle that generates magma, which can lead to volcanic activity. The video describes how a hotspot is a pocket of magma trapped under the Earth's crust, fed by a deep pipeline from the Earth's molten interior. This magma reservoir is crucial in the formation and eruption of supervolcanoes, as it builds pressure that can lead to the ground swelling or a supereruption.

💡Life Renewed

The concept of life renewed refers to the rebirth of ecosystems and the emergence of new life forms following a catastrophic event, such as a supervolcanic eruption. The video suggests that despite their destructive capabilities, supervolcanoes can pave the way for new life by creating new habitats and altering landscapes. The resurgence stage of Yellowstone is an example where wildlife and plant life reclaimed the area, demonstrating the resilience of nature.

💡Geothermal Features

Geothermal features are natural phenomena resulting from the heat of the Earth, such as hot springs, geysers, and fumaroles. The video mentions that some of the world's largest geothermal features emerged after the resurgence stage of supervolcanoes, like Yellowstone, where the caldera filled with freshwater and became a site for these unique geological formations. These features are a testament to the Earth's ongoing geological processes and the potential for beauty to arise from destruction.

💡Natural Beauty

Natural beauty in the context of the video refers to the awe-inspiring landscapes and geological formations that can result from supervolcanic activity. Despite the devastation caused by supereruptions, the video highlights how these events can lead to the creation of breathtaking scenery, such as the geothermal features at Yellowstone. This concept underscores the dual nature of supervolcanoes as both destructive forces and catalysts for the creation of stunning natural environments.

Highlights

Supervolcanoes are the most violent and complex class of volcanoes.

Supervolcanoes can also make way for life renewed after their eruptions.

There are around 20 supervolcanoes scattered across the planet.

They are characterized by large depressions in the ground called calderas.

Supervolcanoes are located above multiple openings in the Earth's crust.

They explode at a magnitude of eight on the Volcanic Explosivity Index.

Supervolcanoes undergo a life cycle of three major stages: surge, supereruption, and resurgence.

The first stage involves a pocket of magma trapped under the Earth's crust called a hotspot.

The hotspot is fed by a pipeline deep into Earth's molten interior.

The supervolcano Campi Flegrei in Italy has caused the ground to swell up to six and a half feet.

The next stage of a supervolcano's life cycle is a supereruption, releasing over 1,000 cubic kilometers of tephra.

The most recent supereruption occurred in New Zealand approximately 26,000 years ago.

The supervolcano Taupo ejected about 1,100 cubic kilometers of tephra in its supereruption.

After a supereruption, a supervolcano's magma reservoir collapses and forms a caldera.

The Yellowstone Caldera in the United States is currently in resurgence after a supereruption 640,000 years ago.

Freshwater collected in the Yellowstone caldera to form a lake after the eruption.

Plants and wildlife returned to reclaim the space after the eruption at Yellowstone.

Some of the world's largest geothermal features emerged after the eruption at Yellowstone.

Supervolcanoes create unparalleled natural beauty in the wake of cataclysmic events.