# Earthquakes and Volcanoes Study Guide 2013 Know the facts about

```Earthquakes and Volcanoes Study Guide 2013
1. Know the facts about the three types of faults:
Normal
Reverse
 Divergent boundary
 Convergent boundary
 Tension stress
 Compression stress
 Hanging wall slides down
 Hanging wall pushes up
Strike-Slip
 Transform boundary
 Shearing stress
 Plates stay even, but
slide past each other
2. Know the facts about the three earthquake rating scales:
Richter Scale
 Measures strength or
magnitude
 1-10 with decimals
 Low magnitude
earthquakes are very
common
 Each whole number is 10
times the last one
Mercalli Scale
 Measures damage done
to property
 Earthquakes in
populated areas will
cause more damage
 Roman numerals from I
to XII
Moment Magnitude
 Commonly used today
 Measures the amount of
energy released by an
earthquake
 Scale 1-10 with decimals
 Each whole number is 10
times the last one
Vocabulary:

Fault – the surface where plates of tectonic rock break and slide past each other

Deformation – process by which the shape of rock changes because of stress

Seismograph – the instrument that records seismic waves

Focus – the point inside the earth where an earthquake starts

Epicenter – the point on the Earth’s surface directly above the focus

Magnitude – a measure of the strength of an earthquake

Intensity – a measure of the damage done by an earthquake or how much it was felt

Viscosity – the resistance of a substance to flow – water has low viscosity, honey is highly viscous

Magma – molten rock under ground

Lava – magma that comes to the surface

Caldera – a large semicircular depression that forms when the roof of the magma chamber drops after
the chamber is empty.
3.
Know the three facts about the three types of earthquake waves:
P-Waves
 Primary waves – leave
focus 1st
S-Waves
 Secondary waves – leave
focus 2nd
Surface Waves
 Slowest waves
 Do the most damage


Move very fast
 Move slower
Can travel through solids
 Travel through ONLY
AND liquids
solids
 Move through pressure
 Move side to side
5. Know the differences in the two types of eruptions:
Explosive
 Very destructive
 Explode with lots of force and speed
 High viscosity Pyroclastic material

Move like water waves,
up and down in a circle
or side to side
Non-Explosive
 Most common type
 Low viscosity lava
6. Describe:
Active volcano
 Erupting now or soon
Dormant volcano
 “sleeping” volcano could
erupt in the future
Extinct volcano
 Has not erupted in
recorded history and
probably won’t ever
again.
7. Know the characteristics of the three main types of volcanoes:
Shield volcano
 Formed from repeated
nonexplosive eruptions
 Dome with gently
sloping sides
 Very large
Composite volcano
 Formed from alternating
explosive and
nonexplosive eruptions
the top
 Medium size
8. Know the sizes of tephra:
I told you in class to skip this question
Cinder cone volcano
 Formed from explosive
eruptions.
 Smaller with steep
slopes
 Larger material lands
closer to the volcano
9. Know the parts/definitions of a volcano: THIS SECTION WILL BE REVIEWED IN CLASS
Crater
Ash cloud
Lateral
vent
Lava
Vent
Rock
Magma
chamber
Shade in the area that would represent the caldera. – all areas above the magma chamber would sink if the magma
chamber top collapsed
10. Know where most volcanoes form. –
Along plate boundaries where there is a subduction zone. – Along the Ring of fire
11. What is the Ring of Fire? –
The plate boundary surrounding the Pacific Ocean has so many earthquakes and volcanoes that it is called the
Ring of Fire.
12. What type of rock does a volcano create after it erupts?
Extrusive igneous rock
13. Review Plate Tectonics study guide.
14. Know how volcanoes can affect climate.
Some very explosive volcanoes can sent pyroclastic dust and ash into the upper atmosphere. It stays there for a
long time and blocks the suns rays. That causes the global temperature to decrease.
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