Question
Which is an accurate statement about volcanoes? They form when magma breaks through the earth’s mantle. They generally occur far from plate boundaries. An alternating sequence of explosive eruptions followed by a more steady flow produces a shield volcano. Molten rock is called lava when it is on the earth’s surface and magma when it is beneath the surface.
Answers
GPT-4o mini
The accurate statement about volcanoes is: **"Molten rock is called lava when it is on the earth’s surface and magma when it is beneath the surface."**
Here’s a brief explanation of the other statements:
1. **"They form when magma breaks through the earth’s mantle."** - While magma can be generated from the mantle, volcanoes specifically form when magma rises to the surface through the crust.
2. **"They generally occur far from plate boundaries."** - Most volcanoes are actually found at tectonic plate boundaries (both convergent and divergent), although some can occur at hotspots which are not located at plate boundaries.
3. **"An alternating sequence of explosive eruptions followed by a more steady flow produces a shield volcano."** - Shield volcanoes are typically characterized by broad, gentle slopes and are primarily formed by the steady flow of low-viscosity lava. Explosive eruptions are more characteristic of stratovolcanoes.
Therefore, the fourth statement is the most accurate.
Here’s a brief explanation of the other statements:
1. **"They form when magma breaks through the earth’s mantle."** - While magma can be generated from the mantle, volcanoes specifically form when magma rises to the surface through the crust.
2. **"They generally occur far from plate boundaries."** - Most volcanoes are actually found at tectonic plate boundaries (both convergent and divergent), although some can occur at hotspots which are not located at plate boundaries.
3. **"An alternating sequence of explosive eruptions followed by a more steady flow produces a shield volcano."** - Shield volcanoes are typically characterized by broad, gentle slopes and are primarily formed by the steady flow of low-viscosity lava. Explosive eruptions are more characteristic of stratovolcanoes.
Therefore, the fourth statement is the most accurate.