Download Volcano Study Guide Extinct – Unlikely to erupt ever again Active

Volcano Study Guide
Extinct – Unlikely to erupt ever again
Active – Likely to erupt in the near future
Dormant – No longer active,
but may activate again
1. What force causes the magma to erupt from volcanoes? Dissolved gases trapped in magma
creates tremendous pressure, then rises up through cracks in the crust carrying the magma with
it.
2. What is the Ring of Fire? It is a major volcanic belt formed by the many volcanoes that surround
the Pacific Ocean.
3. Describe how volcanoes form along the mid-ocean ridge. Volcanoes form when lava oozes out of
cracks in the ocean floor.
4. How does subduction at convergent plate boundaries lead to the formation of volcanoes?
1st Oceanic plate subducts (sinks) through a trench, 2nd It melts in the mantle, 3rd Some magma
rises back through continental crust, 4th When magma erupts, volcanoes form
5. Volcanoes at boundaries where two oceanic plates collide create a string of islands called
Island arc volcanoes . Example: Japanese Islands
6. What is a hot spot? Name a chain of islands that formed as a result of a hot spot?
A hot spot is an area where magma from deep within the mantle melts through the crust, like a
blow torch.
Hawaiian Islands.
7. Describe the three types of lava. A) Volcanic Ash – particles the size of sand B) Cinders – pebble
sized particles C) Bombs – particles that range in size from a baseball to a small car