Yellowstone Caldera Quiz: The Supervolcano's Geology
Old Faithful and Grand Prismatic Spring sit inside the remains of a colossal eruption, and this Yellowstone caldera quiz explains the volcano beneath them. Play an interactive set of 10 questions on the hotspot, three great eruptions, the Lava Creek Tuff, resurgent domes, ground uplift, the Snake River Plain and real eruption odds.
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🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds
Eruptions
How many caldera-forming eruptions has Yellowstone had in the last 2.1 million years?
Latest
What is the most recent caldera-forming eruption called?
Size
Roughly how large is the Yellowstone caldera?
Hotspot
What lies beneath Yellowstone?
Track
Which plain records the hotspot's past path?
Geysers
Roughly what share of the world's geysers are in Yellowstone?
Domes
What are Sour Creek and Mallard Lake domes?
Uplift
What do GPS stations at Yellowstone often record?
Odds
How likely is a super-eruption in any given year, according to the USGS?
Park
When did Yellowstone become the world's first national park?
Your score
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Scroll down to see the explanation for each question.
Explanations: answer key for all 10 questions
- Q1: How many caldera-forming eruptions has Yellowstone had in the last 2.1 million years?
Answer: Three
They occurred about 2.1 million, 1.3 million and 631,000 years ago.
- Q2: What is the most recent caldera-forming eruption called?
Answer: Lava Creek eruption
It formed the present Yellowstone caldera about 631,000 years ago.
- Q3: Roughly how large is the Yellowstone caldera?
Answer: About 45 by 85 km
Its rim is hard to see because later lava flows filled much of it.
- Q4: What lies beneath Yellowstone?
Answer: A hotspot feeding a partly molten magma reservoir
Most of the reservoir is solid rock with a small fraction of melt.
- Q5: Which plain records the hotspot's past path?
Answer: The Snake River Plain
As North America moved southwest, a line of older calderas formed across Idaho.
- Q6: Roughly what share of the world's geysers are in Yellowstone?
Answer: About half
Its heat drives more than 500 geysers.
- Q7: What are Sour Creek and Mallard Lake domes?
Answer: Resurgent domes inside the caldera
They rise and fall as magma and fluids move below.
- Q8: What do GPS stations at Yellowstone often record?
Answer: The ground slowly rising and falling
Uplift and subsidence of centimeters a year are normal for the system.
- Q9: How likely is a super-eruption in any given year, according to the USGS?
Answer: About 1 in 730,000
Smaller hydrothermal explosions and lava flows are far more likely.
- Q10: When did Yellowstone become the world's first national park?
Answer: 1872
President Ulysses S. Grant signed the law.
Yellowstone Caldera Quiz – The Volcano Beneath the Geysers
Yellowstone sits above a hotspot that has fed three enormous eruptions in the last 2.1 million years. The most recent, the Lava Creek eruption about 631,000 years ago, formed the present caldera, roughly 45 by 85 km.
Beneath the caldera lies a magma reservoir that is mostly solid with a small fraction of melt. Resurgent domes such as Sour Creek and Mallard Lake rise and fall, and GPS stations record the ground moving up and down by centimeters.
The hotspot's past path is traced by the Snake River Plain. Yellowstone holds about half the world's geysers, including Old Faithful. The USGS puts the annual chance of a super-eruption at about 1 in 730,000.
What This Quiz Teaches
Science fans and park visitors will enjoy these questions.
- How the caldera formed
- What lies beneath it
- How the ground moves
- Why there are so many geysers
- How likely an eruption is
Did You Know?
- The Yellowstone Volcano Observatory monitors the area.
- Hydrothermal explosions have formed craters in the park.
- Grand Prismatic Spring's colors come from microbes.
- Yellowstone Lake partly fills the caldera.
- Earthquake swarms are common and usually small.
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