Download Chapter 9 Section 1 Notes

Chapter 9 Section 1 Notes
 During an eruption, molten rock, or _________________________,
is forced to the Earth’s surface. Magma that flows onto the Earth’s
surface is called _________________.
Non explosive Eruptions
1. _________________________eruptions are the most common type
of eruption.
2. These eruptions produce relatively calm flows of ______________.
Explosive Eruptions
1. ________________________ eruptions are much rarer than
nonexplosive eruptions.
2. During an explosive eruption, clouds of hot debris, ____________,
and ______________ rapidly shoot out from a volcano.
What Is Inside a Volcano?
1. Magma rises form the magma chamber through cracks in the Earth’s
crust to openings called _______________________.
2. Magma is released from the vents during an eruption.
What Erupts from a Volcano?
1. Magma erupts as either lava or pyrocalstic material.
2. Pyroclastic material forms when ______________is blasted into the
air and hardens.
3. LAVA: The viscosity of lava, or how lava flows, varies greatly. Lava
that has __________________ viscosity is stiff. Lava that has
________________ viscosity is more fluid.
4 types of lava
Aa
This lava pours out quickly and forms
a brittle crust.
Pillow
This lava forms when lava erupts
underwater. It forms rounded lumps
that are the shape of pillows.
Types of Pyroclastic Material
Volcanic bomb
 Large blobs of magma that
harden in the air
 Shape is caused by the magma
spinning through the air as it
cools
Lapilli
 Means “little stones” in Italian
 Pebblelike bits of magma that
hardened before they hit the
ground
Pahoehoe
This lava flows slowly, like wax
dripping from a candle. Its glassy
surface has rounded wrinkles.
Blocky
A cool, stiff lava that does not travel
far from the erupting vent. It forms
jumbled heaps of sharp- edged
chunks.
Volcanic block
 Largest pieces of pyroclastic
material
 Pieces of solid rock
Volcanic ash
 Forms when the gases in stiff
magma expand rapidly and the
walls of the gas bubbles
explode into tiny, glasslike
slivers
 Ash makes up most of the
pyroclastic material