1. Volcanoes

2. Title – Volcanoes
p.1
1/3/17
A Volcano is…
A location where magma (molten rock beneath the earth) reaches the earth’s surface through a vent or crack.
This magma can be released as
Lava,
Gases,
Pyroclastics (fragments of rock).

3. Parts of a Volcano
Magma chamber: contains magma (molten rock) deep w/in the Earth's crust.
Vents: smaller openings on the surface through which magma leaves volcano.
Crater: basin from which magma erupts as lava, gases & pyroclastics
Pipe: tube that connects magma chamber to Earth’s surface

4. You will do this after notes
“p.2”
1/3/17
Parts of a Volcano
Crater
Lava Flow
Magma Chamber
Pipe
Vent
You will do this after notes

5. Viscosity…
Property of fluids, has to do with friction, think of it as the state of being thick & sticky
(honey vs. water)
Magma low silica =>lower viscosity (thin and runny).
Magma high silica =>higher viscosity (thick and slow moving).
high
low

6. Magma/Lava contents… Basaltic magma -- SiO2 45-55 wt%,
Fe, Mg, Ca K, Na.
low silicate content
low viscosity (thin & runny),
gases escape easily (not trapped),
non-explosive eruptions
(most likely shield cone volcanoes)

7. Magma/Lava contents…
Andesitic magma -- SiO2 55-65 wt%, intermediate in Fe, Mg, Ca, Na, K.
a medium level of silica content
intermediate viscosity,
intermediate explosiveness.

8. Magma/Lava contents… Rhyolitic magma -- SiO2 65-75%, Fe, Mg, Ca K, Na.
high silica content
high viscosity (thick & slow moving),
gases cannot escape easily (they get trapped),
very explosive eruptions (most likely cinder cone volcanoes).

9. Magma/Lava contents… Dissolved Gases As dissolved gases explosiveness.
Water Vapor {H2O(g)} is the most common dissolved gas in magma.

10. Explosive vs. Non-Explosive
Essentially is due to viscosity of lava
The more viscous, the more explosive
Amount of Silica
Temperature (colder)
% of Water Vapor

11. Parts of a Volcano Cut out & attach base to “p.2”
1/3/17
Parts of a Volcano
FLAP
Cut out & attach base to “p.2”
Place definitions on appropriate lines of “base”
Place labels with definitions
Place flap over base, attach at top, so that it can be lifted.
Place remaining definition & label on flap.
* You may color, this should be completed before next class!
BASE

12. Today…. Structure & Parts of Volcano
You should be able to label diagram
Structure & Parts of Volcano
Crater, Magma chamber, Pipe, Tube, Vent
Composition of Lava
Magma, gases, & pyroclastics
3 Types of Magma/Lava
Basaltic
Andesite
Rhyolite
You should be able to list these items, most common gas?
You should be able to tell relative amounts of SiO2 in each type, & what type of eruption

13. Wednesday 1/4 Finish Volcano diagram ASAP
Smithsonian/USGS Weekly Volcanic Report
Volcano Discovery
Volcano Webcams
“Yellowstone super volcano could erupt in 2016 and wipe out the earth”