How can we help?
You can also find more resources in our
Select a category
Something is confusing
Something is broken
I have a suggestion
What is your email?
What is 1 + 3?
Chapter 9 - Volcanoes
a vent or fissure in the Earth's surface where magma and gases are expelled.
mostly found on plate boundaries
active volcanoes form where tectonic plates collide
cinder cone volcano
a small, steeply sloped volcano that with explosive eruptions of pyroclastic material
Volcano built by alternating explosive and non-explosive eruptions
A wide, gently sloping mountain made of layers of lava and formed by non-explosive eruptions.
huge lava flows. If lava is thin and runny, it has a low silica content
would have clouds of hot debris, ash & gas (pyroclastic material)
happens when the water content in the magma is high
measure changes in a volcanoes slope
how the lava flows-either slowly or quickly
milky consistency = low viscosity
milkshake consistency = high viscosity
when underground, gathers in the magma chamber
melted rock after it reaches the earth's surface
rock melts when TEMPERATURE INCREASES & PRESSURE DECREASES
forms into a brittle crust that has sharp jagged pieces
has a glassy surface and flows like dripping wax
cool, stiff lava that makes heaps of sharp chunks
lava that forms from an underwater eruption and is characterized by a pillow shape
forms when magma explodes and hardens in the air into ash, dust and gases
pyroclastic material that means "little stones"
can reach the upper atmosphere and circle the Earth for years
large blobs of magma that harden in the air
largest pieces of pyroclastic material
they are pieces of rock
a funnel shaped pit at the top of the volcano
a depression that happens when the magma chamber collapses and empties
deep cracks between two tectonic plates that pull away from each other
located above mantle plumes
ex. volcanoes of Hawaii and other volcanoes far away from tectonic plates
can erupt in the near future
has not erupted in many years, but still could
will never erupt again
large, flat area covered by lava
climate change effect
when volcanic ash reaches the upper atmosphere, it can block sunlight and make global temperature go down
good effect of volcanoes
make very fertile soil that is good for farming