Volcanoes
7.3 NOTES
Inside a Volcano
1. Magma
chamber – the pocket beneath a
volcano where magma collects
2. Pipe – a long tube through which magma
moves from the magma chamber to Earth’s
surface
3. Vent – the opening through which molten
rock and gas leave a volcano
4. Lava flow – the area cover by lava as it pours
out of a volcano’s vent
5. Crater – a bowl-shaped area that forms
around a volcano’s central opening
A volcanic eruption
When a volcano erupts, the force of
the expanding gases push magma
from the magma chamber through
the pipe until it flows or explodes
out of the vent. Once magma
escapes from the volcano it
becomes lava.
(The magma has lost most of its gases
during the eruption.)
Kinds of Volcanic
Eruptions
Quiet Eruptions happen when its
magma is low in silica making the
lava flow easily and the gases bubble
out gently
https://www.youtube.com/watch?v=5
hE2DZdl0IA
Kinds of Volcanic Eruptions
Explosive Eruptions
pyroclastic flow – occurs
when an explosive eruption
hurls out a mixture of hot
gases, ash, cinders, and
bombs
https://www.youtube.com/watch?v=Cvjwt9nnwXY
https://www.youtube.com/watch?v=E4j-PGiSYQI
Stages of volcanic activity
Life Cycle of a Volcano – Geologists often use
the terms active, dormant, or extinct to
describe a volcano’s stage of activity.
Active, or live, volcano is erupting or showing
signs of erupting
Dormant ,or sleeping, volcano is like a sleeping
bear. Scientist expect it may awaken in the
future and become active
Extinct, or dead, volcano is unlikely to erupt
again
Monitoring Volcanoes
 Temperature
increase,
change of shape, monitoring
any gases escaping from the
volcano


Ex. GPS and Satellite Radar signal if
magma is causing the volcano’s
shape to change
Ex. Portable monitoring stations are
dropped into the crater and transmit
seismic data to geologists about the
magma inside
Volcanic Eruptions

https://www.youtube.com/watch?
v=gRdP9_v3USU