When a volcano is high in silica, the volcano usually erupts like this.
What is explosively?
100
These are tall, cone-shaped mountains in which layers of lava alternate with layers of ash.
What are composite volcanoes?
100
Groundwater, heated by magma, rises to the surface and collects in a natural pool.
What is a hot spring?
200
Before lava reaches the surface, the molten material is called this.
What is magma?
200
This is made up of rocky particles about the size of a grain of sand.
What is volcanic ash?
200
This is the huge hole left by the collapse of a volcanic mountain.
What is a caldera?
200
This lava was once fast moving, hot lava. It is now smooth.
What is pahoehoe?
300
The formation of the Hawaiian Islands is one example of this.
What is volcanoes forming over a hot spot?
300
This is the main hazard from a quiet volcanic eruption.
What are lava flows?
300
This is what it is called when ash, cinders, and bombs build up in a steep pile around a volcano's vent.
What is a cinder cone volcano?
300
This type of volcano that is unlikely to erupt again.
What is an extinct volcano?
400
The long tube in the ground that connects the magma chamber to Earth's surface.
What is a pipe?
400
A volcano that is not currently erupting but may erupt again at some time in the distant future.
What is dormant?
400
A mass of rock formed when a large body of magma cools inside the crust.
What is a batholith?
400
This rock forces itself between rock layers and is always younger than the rock around it.
What is intrusion?
500
The force that causes magma to erupt to the surface.
What are dissolved gases trapped in the magma?
500
Geologists can infer this about a volcano that has many small earthquakes near the volcano.
What is the volcano is about to erupt?
500
When magma hardens in a volcano's pipe, the result will eventually be called this landform.
What is a volcanic neck?
500
This substance determines if a volcano will have a quiet or explosive eruption.
What is silica?
500
Explain how the Hawaiian Islands are formed and make a prediction of the future of the Hawaiian Islands.
Possible Answer: The Hawaiian Islands are formed by a hot spot under the Pacific plate. As the Pacific plate continues to drift NW over the hot spot a new island will form.