Earthquakes Flashcards
Are earthquakes common in Taiwan and surrounding countries?
yes
Why is it important to know where earthquakes are more likely to occur?
you need to know how to prepare
what are some hazards associated with the collapse of a building from an earthquake?
power lines down, electrical dangers, collapsed buildings
The movement of the Earth’s plates can create strong ___ that slowly ____ and _____ many rocks
forces, bend and fold
All rocks will ____.
break
Stress adds ____ to the rock in which this energy is ____ until it is released.
energy; stored
When the rock changes _______ or breaks is when the stored energy is released.
shape
What happens at places where rock is under stress and breaks?
energy is released and an earthquake is formed
what are 3 ways that force can cause stress in rocks?
tension, compression, shearing
how do forces acting on rock cause tension?
by pulling away from each other
how do forces acting on a rock cause compression?
by pushing toward each other.
how do forces acting on a rock cause shearing?
by pushing 2 masses of rock in opposite direction
what is a fault?
break in the crust
where do most faults occur?
at plate boundaries
when enough stress builds up in the rock, the rock _____, creating a _____.
breaks, fault
what are three types of faults?
normal, reverse, strike-slip
what kind of stress causes a normal fault?
tension
what kind of stress causes a reverse fault?
compression
what kind of stress causes a strike-slip fault?
shearing
Normal Fault: type of stress and plate movement
tension, divergent
Reverse Fault: type of stress and plate movement
compression, convergent
Strike Slip Fault: type of stress and plate movement
shearing, transform
how can earth’s crust be changed over time
it can be stretched, folded, or uplifted by plate movements
folds are ____ in rock that form ______ earth’s crust.
bends; when compression shortens and thickens the
what kind of stress causes folding of the crust?
compression
what are 3 mountain ranges formed by folding?
appalachian, himalayans, alps
2 types of folds are ___ and ____
syncline and anticline
a fold in a rock that bends _____ into an arch is an _____.
upward, anticline
a fold in a rock that bends ___ to form a V shape is a _____.
downward, syncline
how are folded mountains formed?
the collision of 2 plates can cause compression and folding of the crust over a wide area
the forces that raise mountains can also ___ or raise ____
uplift, plateau
some plateaus form when:
forces in Earth’s crust push up a large, flat block of rock
give a location of a plateau
4 corners region of Arizona Utah Colorado and New Mexico
Earthquakes are detected _____.
daily
some earthquakes are too ____ to notice while big earthquakes can _____, ____, and cause great damage.
small, crack open the ground, shift mountains
the ______ cause earthquakes
force of plate movements
plate movements produce ____ in Earth’s crust, adding ____ to rock and forming faults.
stress
energy
______ increases along a _____ until the rock slips or breaks, causing an ______
Stress
Fault
earthquake
when an earthquake occurs, a great amount of ____ is _____.
energy
released
When an earthquake occurs, a great amount of energy is released. This energy comes in the form of ________
seismic waves
The ___ or ___ of the _____ depends on the material it passes through
speed or path
wave
What does energy in an earthquake wave come from ?
seismic waves
what releases the energy ?
the breaking or slipping of rock
the ____ is the area within the Earth where rocks that are under stress begins to move resulting in an earthquake.
focus
the point above the focus located on the ___ of the earth is called an _____
surface
epicenter
most earthquakes begin in which layer of the earth?
lithosphere
____ carry energy from the earthquake’s _____
Seismic waves
focus
P wave speed: originated from: how they travel: materials traveled through:
first to arrive/fastest
focus (underground)
compress and expand
solids, liquids, gases
S wave: speed: originated from: how they travel: materials traveled through:
second to arrive after P waves
focus (underground)
side to side
solids
Surface waves: speed: originated from: how they travel: materials traveled through:
moves slowly
above ground when P or S waves come to the surface
ground rolls like ocean waves
solids, liquids, and gases
name the most destructive wave and why is it the most destructive?
surface waves because it is above ground and is the slowest wave. Being slow creates more destruction.
Earthquakes are waves of ____ that travel through and on the surface of the Earth.
energy
What does a seismograph measure?
seismic waves
Modified Mercali Scale is rated by:
observing the amount of damage done by the shaking of an earthquake. No use of instruments.
Richter Scale (magnitude scale) is rated by:
seismographs are used to determine the size of the earthquake’s wave
Moment Magnitude scale (magnitude scale) is rated by:
total energy an earthquake releases
what does the Modified Mercali scale indicate?
the amount of damage done by an earthquake
which scale measure the amount of energy released by an earthquake?
moment magnitude scale
on which scale would an earthquake’s strength vary from one place to another? Why?
the Modified Mercali scale because the amount of shaking that people feel and the amount of damage very from place to place
seismographs record information on a
seismogram
the seismogram is a pattern of lines which records an earthquake. the lines on the paper mark time. why is this important to know the time of the vibration?
scientists need to know the time difference between the arrival of P and S waves.
what does the height of the lines represent?
the higher the line, the stronger the earthquake.
what is an aftershock?
smaller earthquakes that occurs after the larger earthquake
where to most earthquakes occur?
at plate boundaries
What region of the US has had the most earthquakes?
western US
where would you expect an earthquake to occur in the US? Why?
California because there are many faults located in California.
List 6 places from around the world that have had many earthquakes
Japan, Philippines, Indonesia, New Zealand, Mexico, Alaska, California
What do all these earthquakes have in common?
they are at edges of plates
list 4 places that have not had many earthquakes. why?
Brazil, Greenland, Norway, Sweden, Russia, Western Africa. They are not near edges of plates.
What is the Ring Of Fire?
A plate composed of the Pacific Ocean that has boundaries with many other plates. Plate boundaries form a ring around the Pacific Ocean.
a force that acts on rock to change the shape or volume
stress
stress that stretches rock so that it becomes thinner in the middle
tension
stress that squeezes rock until it folds or breaks
compression
stress that pushes masses of rock in opposite directions, in a sideways movement
shearing
a type of fault where the hanging wall slides downward, caused by tension in the crust
normal fault
a type of fault where the hanging wall slides upward; caused by compression in the crust
reverse fault
a type of fault in which rocks on either side move past each other sideways with little up or down movement
strike slip fault
a large landform that has high elevation and a more or less level surface
plateau
the shaking that results from the movement of rom beneath Earth’s surface
earthquake
the point beneath Earth’s surface where rock first breaks under stress and causes an earthquake
focus
the type of seismic wave that compresses and expands the ground
p wave
a type of seismic wave in which the shaking is perpendicular to the direction of the wave
s wave
a type of seismic wave that forms when P waves and S waves reach Earth’s surface
surface wave
a device that records ground movements caused by seismic waves as they move through Earth
seismograph
a scale that rates the amount of shaking from an earthquake
modified mercali scale
the measurement of an earthquake’s strength based on seismic waves and movement along faults
magnitude
a scale that rates an earthquake’s magnitude based on the size of its seismic waves
richter scale
a scale that rates earthquakes by estimating the total energy released by the earthquake
moment magnitude scale
the record of an earthquake’s seismic waves produced by a seismograph
seismogram
smaller earthquakes that occur after a larger earthquake
aftershock
a large area of flat land elevated high above sea level
plateau
A flat layered block of rock lies somewhere in earth’s crust. Forces in the crust life a large area upward. Once the rock is lifted, what occurs?
Weathering and erosion changes the edges of the landform. You can see loose rock around the base of the plateau (evidence of rock slides)
