Book 12, Question 111
Why Do Past Eruption Deposits Guide Future Forecasts?
Past eruption deposits guide forecasts because volcanoes tend to repeat their habits. Layers of old lava and ash show where eruptions went and how big they were. The past is a guide to the future.
More fun facts
- Long term volcano forecasts come from mapping and dating a volcano's old deposits.
- Those deposits are the record of past eruptions.
- At one volcano, 11 eruptions in the past 10,000 years left ash and pumice layers that scientists can recognize.
- Every volcano can erupt in several different styles.
- So a forecast always includes a range of possible outcomes, some more likely than others.
Sources: National Park Service, U.S. Geological Survey, U.S. Geological Survey
Questions kids ask
How do old ash layers help?
They show how often and how big a volcano erupted in the past.