Book 12, Question 134
How Do Scientists Find Out When a Volcano Last Erupted?
Scientists find out when a volcano last erupted by using dating tools like radiocarbon dating, tree rings, and ash layers. Old eruptions leave a calendar in the ground. Putting the clues together gives a timeline.
More fun facts
- A volcano is considered potentially active if it erupted in the last 10,000 years.
- Sometimes a volcano is called extinct just because of how long it has been since it erupted.
- Mount Thielsen, north of Crater Lake in Oregon, last erupted about 300,000 years ago.
- Mount Thielsen may once have looked like Mount Hood does today.
- Satellite images help scientists study volcanoes before, during and after eruptions.
Sources: National Park Service, U.S. Geological Survey, NASA
Questions kids ask
How long ago did Mount Thielsen erupt?
About 300,000 years ago.