Volcano Basics
What is the difference between lava and magma?
Both are molten rock. Lava is above the earth's surface, magma is below the earth's surface.
Volcanoes form in how many ways?
two
Where is the Ring of Fire?
Along the rim of the Pacific Plate
What are the main ingredients of lava?
Silicate and gas
A volcano that is currently erupting
Alive volcano
What is a volcano?
a vent in the earth’s crust through which lava, steam, ashes, and gases are forced
What percent of volcanoes are formed via hotspots
10%
How are tectonic plates moving relative to each other at the Mid-Atlantic Ridge?
Away from each other (divergent)
True or false: The more silica in lava means the more easily the lava flows
False
A volcano that has not erupted for a long time but may erupt again
Dormant volcano
What is a crater?
How were the Hawaiian Islands formed?
They were formed by a hot spot
What are rifts AND how are they formed?
deep cracks that form between two tectonic plates as they move away from each other
What are volcanic bombs?
blobs of magma that are shot into the air by a volcano
A small, cone shaped volcano built of ash and cinders that has a single vent
Cinder cone volcano
Magma beneath a volcano is stored in what?
A magma chamber
What is a hotspot?
A place on the Earth’s surface that is directly above a column of rising magma
The rim of the Pacific Plate contains what percentage of all of the earth's volcanoes?
60%
Describe pahoehoe
lava that has a smooth of billowy surface. It flows easily
What is a shield volcano AND what type of eruption(s) is it formed by?
A gently sloping volcano made almost entirely of lava flows. Hawaiian and Icelandic
Explain two ways that volcanoes can grow larger
from the inside when magma remains in the cone without erupting
from the outside when lava escapes through the vent
Explain how volcanoes are formed at subduction zones
The subducted plate melts, and the magma rises under pressure
Explain how Iceland was formed.
It was formed along due to plates diverging, and rising magma formed new crust
What is intrusive action?
when magma flows through fissures and hardens underground
What is a composite volcano AND what type of eruption(s) are they formed by?
A deep-sided volcano made of lava, ash, and cinders. Vulcanian, Plinian, Pelean