Exam 5: Volcanoes

There has never been a globally catastrophic volcanic eruption from Iceland's volcanoes because they only involve gentle lava flows.

In which two environments are shield volcanoes found?

The history of an area's rocks can give a timeline of past volcanic eruptions.

Why do scientists study earthquakes to predict a volcanic eruption?

People have successfully diverted lava flows from populated areas.

Magma with a higher silica content will also have a higher viscosity.

Volcanoes associated with high viscosity magma are usually less dangerous than those with more freely flowing magma.

What is the difference between magma and lava?

Explain the difference between magma formed at subduction zones and divergent plate boundaries.

Why are so many volcanoes found on the Ring of Fire around the margin of the Pacific Ocean?

Most volcanoes are around the Pacific Ocean's "Ring of Fire." Explain why they are there and what kind of volcanoes form there.

The area around Mt. St. Helens is now safe because the volcano is finished erupting and will stay dormant for the next 200 years.

Caldera eruptions can involve the largest volcanic eruptions on earth and they are the rarest.

Explain what viscosity is and how it affects the shape of a volcano. Give one example to illustrate your point.

Unfortunately, volcanoes do not give any signs or indications of when they might erupt.

Which volcano type involves layers of pyroclastic debris and lava flows?

Composite volcanoes can have a long dormant period in which people can forget that they were ever once active volcanoes.

How might you escape from a lahar?

Describe the hazards associated with an ash fall.

Where does tephra come from?