Introduction
A caldera forms when a volcano's magma chamber empties during an eruption and the ground above collapses into the void. The largest calderas are created by supervolcanic eruptions.
Supervolcanic eruptions are thousands of times more powerful than normal eruptions. They can alter global climate for years and have come close to causing mass extinction.
1. Toba Caldera, Indonesia
- Size: 100 × 30 km
- Last Eruption: ~74,000 years ago
- Type: Supervolcanic caldera
Toba is the largest caldera from a known supervolcanic eruption. The eruption 74,000 years ago may have caused a volcanic winter that reduced the human population to as few as 10,000 individuals.
Lake Toba, which fills the caldera, is the largest volcanic lake in the world.
2. Yellowstone Caldera, USA
- Size: 72 × 55 km
- Last Eruption: 640,000 years ago
- Geysers: ~500 (most in the world)
Yellowstone sits on a supervolcano that has erupted three times in the last 2.1 million years. It contains more geysers than the rest of the world combined.
A full eruption would cover much of North America in ash and potentially trigger a volcanic winter. The probability in any given year is about 1 in 730,000.
3. Ngorongoro Crater, Tanzania
- Size: 19 km diameter
- Depth: 600 m
- Wildlife: ~25,000 large animals
Ngorongoro is the largest unbroken caldera in the world. It functions as a natural enclosure for about 25,000 animals including the Big Five.
The crater floor is a UNESCO World Heritage Site and one of the best wildlife-viewing areas in Africa.
4. Aira Caldera, Japan
- Size: ~24 × 20 km
- Location: Kagoshima Bay
- Active Cone: Sakurajima
Aira Caldera is largely submerged beneath Kagoshima Bay. The highly active Sakurajima volcano sits on the caldera's rim and erupts hundreds of times per year.
5. Campi Flegrei, Italy
- Size: 13 km diameter
- Location: Naples metropolitan area
- Population: ~500,000 live inside caldera
Campi Flegrei is a supervolcano with 500,000 people living inside its caldera. The ground has been rising in recent years, raising concerns about a potential eruption.
6. Long Valley Caldera, USA
- Size: 32 × 17 km
- Last Eruption: 760,000 years ago
- Location: Eastern California
Long Valley Caldera was formed by a massive eruption 760,000 years ago. The Bishop Tuff deposits from this eruption are found across much of Nevada.
7. La Garita Caldera, USA
- Size: 75 × 35 km
- Last Eruption: 27.8 million years ago
- Record: Largest known eruption in Earth's history
La Garita produced the Fish Canyon Tuff, the largest known volcanic eruption in Earth's history. It ejected over 5,000 km³ of material, dwarfing any recent eruption.
8. Aso Caldera, Japan
- Size: 25 × 18 km
- Population: ~50,000 live inside
- Status: Active (Mount Aso)
Aso Caldera is one of the largest in the world with an active volcano (Mount Aso) inside it. About 50,000 people live within the caldera, farming its fertile volcanic soil.
Key Facts
- The Toba eruption 74,000 years ago may have nearly driven humans to extinction.
- Yellowstone has about 500 geysers, more than the rest of the world combined.
- Ngorongoro Crater is home to 25,000 large animals in a natural enclosure.
- 500,000 people live inside the Campi Flegrei caldera near Naples.
- La Garita produced the largest known eruption in Earth's history.
Fun Facts
- Yellowstone's magma chamber contains enough magma to fill the Grand Canyon 14 times.
- Ngorongoro Crater has the densest population of lions per area in Africa.
- Campi Flegrei literally means "burning fields" in Italian.
- The Toba eruption ejected about 2,800 km³ of material, 10,000 times more than Mount St. Helens.
Final Thoughts
The world's largest calderas are scars left by Earth's most violent eruptions. These massive craters remind us of the supervolcanic power that lies beneath our feet and has repeatedly reshaped life on Earth.