Natural hazards: a town below a volcano
1 min 45 s. The words are spoken and shown in the picture; the player can also show them as subtitles.
For the Earth and Space Sciences Regents. Topic: Natural hazards, with the past questions on it.
What Dr. Mars says (the words of the video)
People cannot stop a volcano. How can they stay safe?
A town sits in a valley below a volcano.
Homes stand on the valley floor and on a hill.
Many small earthquakes start under the volcano.
Magma moving up can cause them. Dr. Mars's seismometer records them.
These earthquakes can warn that an eruption may come.
A warning can give time to move people to safer ground.
A hazard map sorts places by the chance of harm.
Dr. Mars shades Zone three, the highest chance. Zone one has the lowest.
When the volcano erupts, ash rises high into the air.
Ash can damage aircraft engines, so flights are stopped.
A volcano can also release carbon dioxide gas.
It is denser than air, so it flows downhill.
Homes on higher ground stay above the gas.
The eruption cannot be stopped, but harm can be reduced.
Check yourself! Dense gas flows into the valley. Which home is safest: A, B, or C?
Think about where a dense gas collects.
Answer: C! It stands on high ground, above the gas.
Dr. Mars shaded Zone three, then climbed to Zone one.
Dr. Mars. Free practice for the New York Earth and Space Sciences Regents.