Study Guide – Earthquakes and Volcanoes Test
 Know the definitions of the following words:
earthquake
shearing
tension
stress
compression
deformation
fault
strike slip fault
normal fault
reverse fault
friction
fault block mountain
folds
plateau
focus
epicenter
seismic waves
seismograph
magnitude
Mercalli Scale Intensity Scale
volcano
hot spot
magma chamber
magma
Ring of Fire
pyroclastic flow
active
dormant
extinct
shield volcano
cinder cone volcano
composite volcano
caldera
crater
pipe
vent

Know the difference between P, S, and surface waves
P waves: -travel through solids, liquids, gases
- Move the fastest
- “primary waves”
- - stretches and squeezes like an accordian
S waves: -second fastest
- Move side to side like a snake
- Cannot travel through liquid
- “secondary waves”
Surface waves
- Move along Earth’s surface
- Travel slowly
- destructive

Be able to describe how to locate the epicenter of an earthquake
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
Know the different ways to measure an earthquake
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
Use seismographs: instruments that record seismic waves
Find difference in arrival times between P and S waves
Use a map to draw circles with the radius of the circle being the epicentral distance
Intersection of all three circles is the epicenter
Mercalli Intensity Scale: rates earthquakes according to level of damage, I-XII
Richter Scale: measures magnitude of the size of earthquake by measuring seismic waves
Moment Magnitude scale: estimates total energy released
Be able to identify and label a normal, reverse, and strike-slip faults
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Normal: tension pulls crust, hanging wall goes down, footwall goes up
Reverse: compression pushes crust together, hanging wall goes up, footwall goes down
Strike-slip: shearing force cuases plates to move past each other, creates friction

Be able to name, describe, and label basic features of a volcano (magma chamber, pipe, vent,
crater, lava flow)
Crater
Vent
Lava Flow
Pipe
Magma Chamber

Explain the type of stress and faults that accompany a divergent, convergent, and transform boundaries.
- Divergent: tension, normal fault
- Convergent: compression, reverse fault
- Transform: Shear, strike-slip fault

Explain how a shield, cinder cone, and composite volcanoes are alike and different.
- Shield: wide, gently sloping sides, quiet eruptions
- Cinder Cone: steep, cone-shaped hill, made of pyroclastic materials, explosive eruptions, small
- Composite: tall, cone-shaped, explosive followed by quiet eruptions

Explain how volcanos effect climate and surface changes.
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
Gases and ash go into atmosphere, block’s sunlight, global temperatures drop.
Explain types of lava flow and types of eruptions
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Aa: pours out fast, forms brittle crust
Pahoehoe: flows slowly, round and wrinkly
Pillow: underwater, rounded lumps
Blocky: oozes, cool and stiff, stays near
Explosive: high in silica, high viscosity, think/sticky
- Can build up in pipe and explode
Quiet eruptions/non-explosive
- Low silica, low viscosity, flows easily, oozes out quietly, buries everything, Hawaii

Explain the properties of magma
Viscosity: resistance of liquid to flow
- High – think, flows slowly, sticky
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Depends on silica content: high silica = higher viscosity, low silica = low viscosity
 Explain the similarities and differences of a hot spot, volcanic belt, and island arcs
Hot spot
- Magma melts through crust, found in middle of plates or along plate boundaries, volcanoes form
above hot spot
Volcanic Belt
- Forms along plate boundaries
- Many volcanoes from divergent or convergent boundary
- Ring of Fire: major volcanic arc in Pacific Ocean
Island Arcs
- String of volcanic islands
- Formed from subduction at converging oceanic plates