caldera
What is a circular depression that forms when a magma chamber empties and causes the ground above to sink
cinder cone volcano
What is a small, steeply sloped volcano that forms from moderately explosive eruptions of pyroclastic material
composite volcano
Name a volcano made of alternating layers of lava and pyroclastic material; also called stratovolcano
crater
What is a funnel-shaped pit around the central vent of a volcano
hot spot
Name a place on Earth's surface that is directly above a column of rising magma called a mantle plume
lava
Name the magma that flows onto the Earth's surface
pyroclastic material
What do you call those fragments of rock that are created by explosive volcanic eruptions
rift
What is a deep crack that forms between tectonic plates as they separate
shield volcano
What is a large, gently sloped volcano that forms from repeated, nonexplosive eruptions of lava
silica
What compound do you get when you combine silicon and oxygen atoms
vent
What is the name of a hole in the Earth's crust through which magma rises to the surface
volcano
What do you call a mountain that forms when molten rock, called magma, is forced to the Earth's surface
Magma
What is forced to the Earth's surface when a volcano forms?
pyroclastic material
An explosive volcanic eruption can give flight to solid rock fragments called
explosive eruptions
What are caused by silica-rich magma which tends to harden in a volcano's vent
particle size
Pyroclastic material is classified primarily by
Blocky, Pahoehoe, Aa, Pillow Lava
Types of Lava
Blocky Lava (1st Definition)
Kind of lava which is cool, stiff lava that cannot travel far from the erupting vent
Blocky Lava (2nd Definition)
Kind of Lava which usually oozes from volcano, forming jumbled heaps of sharp edged chunks
Pahoehoe Lava
Kind of Lava which flows slowly, like wax dripping from a candle, forming a glassy surface with rounded wrinkles
Aa Lava
Kind of Lava which is stiffer and pours out quickly and forms a brittle crusts
Pillow Lava
Kind of lava that forms when lava erupts underwater. Forms rounded lumps that are the size and shape of pillow
Shield, Cinder cone, Composite Volcano
Different types of Volcanoes
Shield Volcano
Large, gently sloped volcano. Forms from repeated, nonexplosive eruptions of lava
Cinder cone Volcano
Small, steeply sloped volcano. Forms from moderately explosive eruptions of pyroclastic material
Composite Volcano
Also called Stratovolcano. Made of alternating layers of lava and pyroclastic material
Volcano erupts when the pressure within the molten magma below the surface becomes stronger than the strength of the rocks on the surface that make up the volcano. The magma then finds the path of least resistance to the surface and erupts
How does volcano erupt
Volcanic blocks, Volcanic bombs, Lapilli, Volcanic ash
types of Pyroclastic material (Largest to smallest)
number & intensity of small earthquakes increases, bulges in the volcano slopes may form as magma pushes against the inside of volcano, ratio of certain gases increases, measurement of temperature from orbit can indicate eruption
Describe signs that might indicate that a volcano might erupt soon
nonexplosive eruption
kind of lava where continuos flow of lava pours quietly from the crater
ring of fire
an area of volcanic activity along the borders of the Pacific Ocean, This refers to the belt or chain of volcanoes and earthquakes surrounding the Pacific Ocean.