Download dynamic planet: earthquakes, volcanoes, and plate tectonics

DYNAMIC PLANET: EARTHQUAKES, VOLCANOES, AND PLATE TECTONICS
Scrimmage 2009
PART 1: The Structure of the Earth
1. The soft weak structural layer 'weak zone' of the earth's mantle that is actually capable of
flow is called the aesthenosphere . The rigid sphere of rock situated just above it is called the
lithosphere. Both of these layers would be considered compositional or mechanical layers of
the earth?
2.
The most prominent mountain range on the Earth is the Himalayas . By contrast, narrow
deep troughs in places more than 11,000 meters deep, occur in the sea floor adjacent to
volcanic islands and young mountain chains on the edges of continents. These deep narrow
troughs are called trenches ?
.
3.
According to the theory of plate tectonics , the rigid lithosphere of the Earth is broken
into numerous segments called plates . The three distinct types of boundaries between these
segments of rigid lithosphere are known as convergent boundaries, divergent , boundaries, and
transform boundaries.
4.
As new oceanic lithosphere is created at the ocean ridges, the old oceanic lithosphere is
pushed aside. This process is called sea floor spreading and occurs at a rate of 5cm per year
(label units properly). This is an excellent example of which type of boundary? divergent
5.
Stable continental interiors are known as shields and are largely composed of granite
The age of rocks in these areas are some of the oldest known on earth and are roughly 3.8
billion years old.
6. Regions where the oceanic lithosphere is being consumed and melted are called subduction
zones .
.
7. Along most continental coasts a gently sloping platform extends seaward from the shore and
is called the continental shelf. At the seaward edge of such platforms a steep drop off, called a
continental slope occurs.
8.
Review the following characteristics and associate them with one of the compositional
layers of the earth: crust mantle or core.
a. core
b. mantle
c. crust
d. mantle
e. core
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composed mostly of iron with some nickel and other elements
over 80% of the earth's volume is in this compositional layer
typically thin and composed of igneous rocks like granite and basalt
although it behaves like a solid when transmitting earthquake waves it
actually flows
it is compositionally very dense (11 g/cm3) and yet its outer layer is
capable of flow while the inner layer behaves like a solid. It's rotation
generates the earth's magnetic field.
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9.
As you go deep into our planet the pressure and temperature rise, radioactive elements
decay releasing heat deep in the core. The only way the interior of the earth can transfer its
internal heat to space is through a process called convection , where hot materials rise, move
laterally, cool and then descend again.
10.
Long before the continents began to drift apart they were joined together in a super
continent called:
a.
wonderland
b.
Atlantis
c.
Pangea
d.
Gondwanaland James Porter would pick this but you shouldn’t!
11.
Which of the following is true about the lithosphere?
a.
It is the relatively solid outer layer of the earth
b.
It is generally 100 km thick sometimes more sometimes less
c.
It is composed of basaltic and granitic rocks
d.
all of the above
12.
Which of the following is true about the asthenosphere?
a.
It is a relatively weak zone of the earth's layers
b.
It is only very slightly melted (1-5%)
c.
It is plastic
d.
all of the above
e.
a and c
13.
For each of the following statements indicate true or false.
a. true The densest portion of the earth is the mantle
b.false Shields and ocean floors are the oldest rocks on the planet at about 3.8 billion
years old.
c. true The density of continental rocks is generally less than the density of sea floor
rocks
d. true The San Andreas Fault of California is a transform boundary
e. false When continents collide, subduction happens rapidly
f. true Some of the oldest mountains in the world are the Urals and the Appalachians
while the youngest mountains are those forming around the ring of fire
g. true The formation of mountain ranges in the pacific Northwest is due to subduction of
oceanic crust under the continental crust.
14.
Isostacy is the principal that explains why Greenland has been deformed by some
11,000 feet of glacial ice and is now rebounding as the ice melts. It is the plastic flow of the
asthenosphere that allows this process to occur.
15.
Which of the following help to explain magnetic striping of the basaltic ocean floor?
a.
Periodic reversal in the earth's magnetic field
b.
divergent boundary of the mid Atlantic rift
c.
convection currents in the asthenosphere create magnetic anomalies
d.
all of the above
e.
a and b
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16.
It was the fit of the shape of South America and Africa that initially lead Alfred Wegner to
consider the possibility of continental drift, true or false? true
17.
The ocean crust at the mid Atlantic ridge is less dense that oceanic crust that is further
east or west of the ridge, true or false? true
18.
Hugo Benioff studied earthquake foci along the west coast of South America. He
discovered that the foci are quite shallow near the oceanic trench west of South America and
that as you move east, the earthquake foci become deeper .
.
19.
Some volcanoes tend to erupt very violently or explosively while other volcanoes such
as those in Hawaii, tend to erupt quietly and create massive flows of lava .
.
20.
The Mariannas Trench is the deepest part of the Ocean and represents a zone of
subduction.
21.
Identify each of the following statements or descriptions with a number from the drawing
below.








This layer includes both the more bouyant felsitic rocks and the denser basaltic rocks that
compose the earth as humans see it. (1)
This layer is composed of intensely hot nickle and iron (3 or 3a & 3b)
This layer is composed of materials rich in
iron, magnesium and calcium (2)
This layer includes the aesthenosphere
and both layers of the mantle (2)
Aesthenosphere (5)
Outer core (6)
Inner core (7)
Lithosphere (4)
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22.
The most massive volcanic explosion in the last 25 years in the United States was the
eruption of Mt St. Helens and is caused by the rising plutons of melting magma from the
subduction of oceanic crust under continental crust.
Part 2
VOLCANOES
23.
It is well known that the explosiveness of a volcanic eruption is directly correlated with
the viscosity of the magma associated with it. Which of the following factors affect the viscosity
of magma?
a.
temperature
b.
Silica content
c.
thickness of overlying crust
d.
dissolved gas content
e.
all of the above
f.
a, b, and d
g.
a and b
24.
Basaltic or mafic magma tends to be more viscous and has a silica content of roughly
50% while Felsic Lavas have a silica content of roughly 70% and tends to flow freely, true or
false?
25.
Magma with more gas content tends to erupt explosively as gas is released, true or
false?
26.
The more fluid, low silica content basaltic flows tend to let dissolved gasses escape and
allowing for a more quiet eruption, true or false?
27.
Complete the following table;
composition
silica content
mafic or
basaltic
magma
Andesitic
magma
Felsic
or granitic
magma
viscosity
gas content
pyroclastic
tendency
volcanic
landform
50%
least
least 1-2%
least
Shield cones
basalt
plateaus
cinder cones
60%
intermediate
Intermediate
3-4%
intermediate
Composite
cones
70%
most
most 4-6%
greatest
Volcanic dome
pyroclastic
flow
28.
The most prominent gas in magma is water vapor. Other important gases in magma are
carbon dioxide , nitrogen ,sulfur dioxide .
29.
When basaltic volcanoes flow, they produce unique types of lava called
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a.
aa
b.
pahoehoe
c.
tahaha
d.
pillow lava
e.
a, b, and d
f.
a and b
30.
When Felsic magmas, highly charged with gasses and very viscous, erupt from a
volcano they tend to release pulverized rock, lava and glass fragments from the vent. Equally
gasses propel basaltic magma high into the air launching incandescent blobs of lava that cool
and fall around the vent. All of these materials ejected from the volcano are collectively called
a.
pyroclastics
b.
ash flows
c.
cinders
d.
a big mess
31.
Viscous eruptions also release ash and dust during explosions. These fine glassy
fragments fall and fuse to form an incredibly light volcanic rock that can float on water. What is
this rock called? Pumice
32.
Rank the following volcanic ejecta by size from smallest to largest, bombs, lapilli, blocks,
and cinders.lapilli cinders, blocks and bombs
33.
Mauna Loa is a fine example of a shield volcano.
34.
Rank the following volcanic cones by size from largest to smallest, cinder cones,
composite cones, shield volcanoes. Shield, composit, cinder
35.
mars
What is the biggest volcano in our solar system, where is it found?olympus mons on
36.
The majority of the volcanoes found in the ring of fire are what type of volcanic cone?
What is another name for this type of volcano. Composite/ stratovolcano
37.
Mount Vesuvius is responsible for the destruction of the ancient Roman city below it
called Pompeii . Here an especially dangerous type of pyroclastic flow called Nuee
Ardente a (glowing avalanche) engulfed the city and cast the inhabitants in stone. These
pyroclastic flows are known for their speeds of 200 kph.
38.
Another dangerous attribute of composite cone eruptions are the massive mud flows that
can develop that are called lahars .
39.
Many volcanoes have steep walled craters which are called caldera when it exceeds 1
km in diameter. These are caused by the collapse of the magma chamber following an eruption.
40.
As very viscous lava is forced out of a vent it may produce a raised mass of congealed
lava called a lava dome. Would you expect these to develop in the Hawaiian Island volcanoes?
No the lava is not viscous enough
41.
A huge land form in the western United States is the Columbia Plateau a lava flow that is
nearly 200,000 square km with an average thickness of 1 km. What type of magma would you
suspect formed this land form? basalt
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42.
Large masses of magma deep in the earth are called plutons, named for pluto, god of
the lower world. As magma in these plutons seeps vertically and horizontally through fissures in
overlaying rock layers they solidify to form land forms we call dikes if they cut across layers of
overlying rock and sills if the run between overlying layers of rock. However the largest intrusive
igneous bodies are batholiths, hundreds of km long and up to 100 km wide and they form as
plutons merge.
43.
The presence of volcanic activity is not randomly spread around the globe instead it
tends to be concentrated at zones of convergence and divergence.
.
44.
Match the following:
a.
Aleutian Island Volcanoes
3
1. intra plate continental volcanism
b.
Yellow Stone hot spot
1
2. oceanic divergence
c.
Mid oceanic Ridge
2
3. Subduction Zone volcanism
d.
Hawaiian Hot Spot
4
4. intraplate oceanic volcanism
e.
Andes Mountains
3
5. continental divergence
f.
African Rift zone
5
45.
Is it possible for volcanoes to change earth's climate? How? If so, would it tend to
increase or decrease the earth's mean temperature? Yes, ejects particulates into stratosphere
blocking light and reducing the temperature of earth.
46.
What was the name of the biggest eruption in the last 2000 years?Tambora
47.
In the image to the right you see a cylindrical body of rock
standing above the surrounding terrain after the rest of the volcano
has been eliminated by erosion. This is called a volcanic neck .
Now look at the image to the left. Is it the same geologic structure
as the image below (yes or no)? Why do they look so similar?
No, they look the same because they are both formed of columnar
basalt. It is a lava flow that cooled slowly.
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48.
Study the profiles of the following volcanic cones and indicate which is a cinder cone,
which is a shield volcano, and which is a stratovolcano.?
a.cinder
b.shield
c. composit/stratovolcano
49.
What are the three main factors that determine the nature of volcanic eruptions?
Gas content, silica content and temperature
50.
Granitic plutons located near subduction zones are probably produced mainly by which
of the following:
a.
hot spot activity
b.
partial melting of water-rich materials that were subjected to high temperatures
c.
fractional crystallization of magma produced by partial melting in the subduction
zone
d.
fractional crystallization of magma from deep within the earth mantle
PART THREE:
EARTHQUAKES
51.
The vibration of the earth produced by the rapid release of elastic energy stored in the
earth’s rocks is called an earthquake .
.
52.
What is the difference between the focus of an earthquake and the epicenter?
The epicenter is on the surface the focus is the actual center of the earthquakes origin
53.
The shock waves that occur after an earthquake are called aftershocks , while the shock
waves that precede an earthquake are called foreshocks .
54.
The study of earthquake waves is called seismology, true or false?
55.
The recordings obtained from a seismograph are called what?seismogram
56.
During an earthquake, some waves travel along the earth's surface and are therefore
called surface waves. Others travel through the earth and are called body waves. Body waves
are further divided into two types of waves, what are they? P or primary and s or secondary
waves
57.
P waves are compressional and can travel through solids, liquids, and gasses, and
change the volume of intervening materials in the direction of their travel, true or false?
58.
S waves on the other hand are Shaking waves and temporarily change the shape of
materials at right angles to the direction of their travel. Fluids and gasses will not transmit S
waves, true or false?
59. Which wave type travels faster through rock? P or primary How much faster?1.7 x
60. Surface waves travel at 90 percent of the velocity of an S wave, true or false? What is
another name for these surface waves?long waves
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61.
By measuring the time between the first P wave and the first S wave and using that
information on the time travel graph we can determine what?
a.
distance from the focus
b.
direction to the focus
c.
distance from the epicenter
d.
direction to the epicenter
e.
c and d
f.
a and b
62.
By triangulating the distance from three (a number) recording centers, the epicenter of
the earthquake can be determined.
63.
In order to know the focus of an earthquake you need to know not only the epicenter but
the depth below the surface.
64.
The Benioff Zone is a seismic region near a trench that has increasingly deep
earthquake foci as you move away from the trench and indicates the direction of movement of
the subducted crust true or false?
65.
Earthquake intensity is measured on the Mercalli Intensity Scale, and assesses the
damage from a quake at a specific location, but is not really predictive of the innate strength of
an earthquake.
66.
The amount of damage caused by an earthquake depends on which of the following:
a.
Strength of the Quake
b.
distance from the epicenter
c.
nature of the surface (rock, sand, soil?)
d.
building codes
e.
all of the above
67.
Since Earthquake intensity is somewhat unrelated to just the strength of the earthquake
we now use a scale that ranks quakes by magnitude which is called the Richter Scale.
This
scale is a linear scale or a logarithmic scale? (choose one). Each unit in this scale relates to
a ten (number) fold increase in energy released and a
32 fold (also a number) increase
in the amplitude of the S wave.
68.
One of the most dangerous and destructive effects of an earthquake has to do with the
effect of ground motion on water. Seiches are the rhythmic sloshing of water in lakes and
reservoirs and bodies of enclosed basins like the Gulf of Mexico. Name another devastatingly
dangerous water-earthquake related phenomena that can devastate shorelines hundreds of
miles from an earthquake.Tsunami
69.
Although these huge waves can travel in the open ocean virtually undetected as a small
swell and at extremely great speeds (800 kph) as they approach the continental shelf, they slow
down and increase in height dramatically.
70.
Land slides, ground subsidence and Fire are also great earthquake hazards. What great
American Earthquake suffered from fire? What other great American Earthquake suffered from
Tsunami and liquefaction of the ground? San Fransisco earthquake and Alaska earthquake of
64
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71.
Examine the Seismogram below and note the features labeled A through G. On the
lines provided beside each item shown below (a-d) note the letter A through G that corresponds
to that item
a.c
an S Wave
b.g
the first P wave
c.c
a surface wave
d.d
the first S wave
e.b
an L wave
PART FOUR: PLATE TECTONICS
72.
Alfred Wegener is the 'father' of continental drift and he suggested a primordial
supercontinent called Pangea .
.
73.
Which of the following were early evidence of continental drift?
a.
fit of the continents
b.
fossil record
c.
rock types
e.
paleoclimatic evidence
d.
all of the above
74.
The temperature that when a magnetized mineral is heated above, it will lose its
magnetism is called the Curie point, true or false?
75.
More current evidence for continental drift includes which of the following
a.
paleomagnetism
b.
sea floor spreading
c.
geomagnetic reversals
d.
Polar wandering
e.
mid-oceanic magnetic stripes
f.
all of the above
76.
Name the three types of plate boundaries convergent divergent and transform
77.
Name as many plates as you can think of.
Antarctic African Eurasian Australian, Indian, Phillippine, Pacific, North American, Juan de Fuca,
Nazca, Coscos, Carribean, south American, Scotia
78.
Name two divergent boundaries, one in the Pacific Ocean and one in the Atlantic Ocean.
Mid atlantic ridge, East Pacific Rise
79.
Sea floor spreading is a result of what type of plate boundary?divergent
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80.
If a divergent boundary occurs on a continent, what geologic feature is created? Can
you name one that exists in Africa? Rift Valley East African Rift Valley
81.
At divergent boundaries new crust is being made or destroyed? made
82.
At convergent boundaries continental crust is being made or destroyed? What is the
name of the zone where this is occurring? Made, subduction zone
83.
As two plates collide, what determines which will go under and be subducted? density
84.
As crust is subducted down into the asthenosphere, the foci of earthquakes follows the
subducted crust and becomes (shallower or deeper).
85.
As oceanic crust is subducted under oceanic crust what feature appears in the oceanic
crust over the subducted plate and runs parallel with the oceanic trench?island arc
86.
When continental crust collides with continental crust neither will subduct below the
other because of the low density and buoyant nature of continental rock. What geologic feature
appears and runs parallel with the boundary between the colliding plates? Give an
example.mountains Himalayas
87.
When oceanic crust is subducted below continental crust there is an accumulation of
deformed sediment and scraps of oceanic crust called an accretionary wedge that add to the
mass of the continent.
88.
The plate boundary characterized by strike-slip faulting where plates grind past each
other is called?transform boundary
89.
Examine the image to the right. Here
an isolated point exists where magma is
upwelling from the mantle and creating a
chain of oceanic volcanoes. This point is
called a hot spot . If the top of your page is
north, then what direction is the oceanic plate
moving?Northwest
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PART FIVE: JUST FOR THE FUN OF IT!
90. Identify the image to the right. How is it
formed?
This is a caldera. You can tell because it is
huge, notice the quadrangle markings. It is
formed when, after an eruption the magma
chamber below is emptied and finally
collapses in on itself.
91.
In the image to the left, the
darkened area is not lava but
constitutes a significant volcano
hazard. What is it, and how is it
formed?
It is a lahar, formed when snow and
ice are rapidly melted during an
eruption and mixed with debris forming
a quick moving and sometimes hot
mud flow.
92.
The image to the right shows damage to a
building caused by an earthquake. What geologic
process caused this type of failure?
This type of tipping of buildings during an earthquake is
caused by a type of ground failure called liquefaction.
93.
In the image to the left some foolish person
stopped long enough to snap this picture. What was he
looking at? What should he be doing? Just moments
before this picture was taken people sunbathing on the
beach noticed something unusual that could have saved
their lives, what?
This is a tsunami, he should be running for his life, the
ocean went out away from shore only to return with a
vengance
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a
94. In the image to the left, which set of images
illustrate Body waves (choose all that apply)? Which
illustrate Surface waves (choose all that apply)? Identify
the specific type of wave by name for a through d
b
a & b are body waves, while c and d are surface waves.
A is a P wave, B is a S wave, C is a Love wave, D is a
rayleigh Wave
c
d
95. In the image to the right you see
one of the most frightening things that
can happen to you if you are near a
volcanic eruption. What is it and how
fast can it go? Instead of stopping to
snap this photo, what should the
photographer really be doing?
This is a nuée ardente. Rapidly moving
volcanic pyroclastic that will burn you
alive. It can travel at speeds up to 200
kph. Running for his life.
96.
In the image to the left this is by a
single member of a group of oceanic
islands near the Marianas Trench. It is a
beautiful example of what type of volcanic
formation (not type of volcano) ? If we
were flying into this area to observe the
eruption what hazard should we be most
concerned about?
volcanic Island arc.
planes
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97. In the image to the right identify the type of
basalt? What makes it form this way?
Columnar basalt, very slow cooling so large basaltic
crystals can form.
98. In the image to the left you see a
very thick volcanic deposit several
hundred feet thick. This deposit is the
result of a pyroclastic flow of very fine
grained materials ejected during a
volcanic eruption that rides on a cushion
of air until it begins to cool and the
particles become welded into this rock
formation. What is it?
tuff
99.
Dr. Anne and her band of wild science
Olympians were camping on the edge of this
lake. All day they had felt small earthquakes
coming from the lava dome in the middle of the
lake.
They
were
taking
meticulous
measurements at all the nearby surface water
gauging stations at the mouths of streams when
a particularly large quake occurred. Casey
O’donnell noticed something funny on the lake’s
surface (see the image below). He pointed it out
to Dr. Anne who took her time snapping a
run!
picture and then calmly yelled
What in
the world did they see? Seismic seiche
the end, thank goodness!
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