Questions for ‘As Yellowstone’s supervolcano slumbers, another big danger lurks’

The area around West Thumb Geyser Basin and Yellowstone Lake has been rocked in the past by many hydrothermal explosions. They’re powered by the same heat from underground magma that feeds the park’s famous hot springs and geysers.
Siraphob Tatiyarat/Moment/Getty Images
To accompany ‘As Yellowstone’s supervolcano slumbers, another big danger lurks’
SCIENCE
Before Reading:
- Consider the word hydrothermal. This word starts with a prefix: hydro. Think about where you have heard this prefix and in what context. What do you think this prefix means? The word hydrothermal ends with a suffix: thermal. What might this suffix mean? To the best of your knowledge, piece together the meaning of hydrothermal based on this information.
- A pressure cooker is a household appliance that cooks food quickly in a pressurized container. A small amount of water must be added to the pressure cooker to work properly. Then, the lid is sealed, and the water is heated into steam. Based on this information, explain the source of the “pressure.” Be sure to explain the role of water in this pressurization process. Modern pressure cookers have many safety devices, such as valves that open if the pressure becomes too high. Why do you think it’s vital for these appliances to have such safety features?
During Reading:
- How many years ago did Yellowstone’s volcano last erupt?
- What was the first sign of trouble observed by visitors to Japan’s Mount Ontake on September 27, 2014?
- How did water contribute to the Mount Ontake disaster?
- What is a phreatic explosion?
- What is the source of the “sour” smell in Yellowstone National Park’s Pocket Basin?
- During a 1966 visit to Yellowstone National Park, Donald White noticed something that led him to conclude its Pocket Basin was a huge crater. He thought it was left over from a past hydrothermal explosion. What did he see that caused him to think this?
- Scientists believe an underground lake once existed beneath what is now Pocket Basin. What kept this superheated water from vaporizing?
- What “change at the surface” did scientists conclude resulted in the explosion at Pocket Basin? Explain the chain of events.
- How wide is Elliot’s crater in meters?
- What tools did scientists use to learn more about Yellowstone Lake? Explain what scientists were able to understand by using each tool.
- What caused the rounded domes on the lake’s floor?
- How big is the North Basin Hydrothermal Dome? Why does Lisa Morgan describe it as a “perfect candidate for a potential hydrothermal explosion”?
- According to core sample data, how many thousands of years ago did Elliot’s crater form?
- What geological event do scientists believe triggered the explosion of Mary Bay? How many years ago did this explosion likely occur?
- Contrast the amount of material expelled from the Mary Bay explosion with the 1962 Storax Sedan nuclear test.
- How does the risk of big hydrothermal explosions change over time? What are the factors that could heighten or lower the risk of explosions?
After Reading:
- Scientists obtain a core sample by drilling a tube deep into the lake floor and drawing out a long cylindrical sample. Scientists in this story used core samples for clues to the geological history of Elliot’s crater. How might scientists use such samples to figure out what happened long ago? What is an example from this story about how such data were used to infer something that happened in the past? Use the word phreatic explosion in your answer.
- How might learning an area’s geological history help people understand what may happen in the future? Give a specific example of how such data might be used to help people.