# Chapter 19 Review Earthquakes.

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Chapter 19 Review Earthquakes

Movement occurs along fractures in rocks when _____.
stress equals the strength of the rocks involved stress overcomes the strength of the rocks involved stress is applies to the rocks involved stress is less than the rocks involved

The strain which causes a material to twist is known as
stress compression tension shear

The strain which causes a material to pull apart is known as
stress compression tension shear

P-waves and S-waves are also known as ____.
surface waves ground waves body waves first waves

Which point marks the epicenter of the earthquake?
B C D

At which point will the most damage as a result of the earthquake occur?
B C D

What is true about the focus?
It is the point where the most surface damage will occur. It is the point where the surface waves originate and spread out. It is the point where the waves are attracted. It is the point of failure where the waves originate.

What keeps the stable part of this seismometer from moving during an earthquake?
inertia gravity its mass its location

Which part of the seismometer does not shake during an earthquake?
the frame the spring the rotating drum the pendulum and pen

Use the graph to answer the questions.

A seismogram is located 4500 miles away from the epicenter of an earthquake. What is the difference in time between when the P-waves reach the seismogram and the S-waves reach the seismogram? 5 1/2 minutes 6 minutes 10 minutes 22 minutes

Which type of material would be best to use for construction in an area prone to earthquakes?
Concrete Brick Wood Stone

Organize the locations from lowest to highest hazard.
Earthquake History Strain Buildup Rate A many earthquakes slow B few earthquakes moderate C fast D B, A, D, C C, D, A, B A, B, C, D B, A, C, D

Seismologists have assessed a particular area and predict that an earthquake occurs every 17 years in that area. If the last earthquake occurred in 1998, when will the next earthquake most likely occur? 2010 2015 2017 2025

Over the past 250 years a city has experienced 23 earthquakes at rather regular intervals. Approximately how often have these earthquakes occurred? every 50 years every 10 years every 100 years every 5 years

A city is located over an active fault, but has not experienced an earthquake for a long period of time. The city is most likely located where? over a seismic gap in an area of low recurrence over minimal strain accumulation at a location of low seismic risk

____ and the amount of strain released during the last quake are used in earthquake probability studies. Seismic belts Strain accumulation Fault scarps Tsunamis

On a seismometer, vibrations of the ground do not move the ____.
frame spring recording drum suspended mass

A ____ fault forms as a result of horizontal compression.
blind normal strike-slip reverse

The San Andreas Fault, a result of horizontal shear, is a ____ fault.
blind normal strike-slip reverse

The locations of seismic belts are determined by plotting ____.
earthquake epicenters seismic gaps earthquake foci epicentral distances

A numerical scale of earthquake magnitude that takes into account the size of the fault rupture is the ____. Richter scale modified Mercalli scale moment magnitude scale epicentral distance scale

formation of fault scarps. surface ruptures.
Deaths associated with earthquake deaths in sloping areas can result from tsunamis. landslides. formation of fault scarps. surface ruptures.

Does not pass through Earth’s liquid outer core
surface wave P-wave S-wave

Does not pass through Earth’s interior at all
surface wave P-wave S-wave

Squeezes and pulls rocks in same direction as the save travels
surface wave P-wave S-wave

Is refracted by Earth’s core
surface wave P-wave S-wave

Absence of this kind of waves results in a shadow zone
surface wave P-wave S-wave

Causes structures to sink into the ground
Liquefaction of soils Collapse of higher, intact floors onto ground floors Vertical motions of the seafloor during an earthquake Natural sway of intermediate buildings equals the period of vibration of the earthquake

Type of structural failure called “pancaking”
Liquefaction of soils Collapse of higher, intact floors onto ground floors Vertical motions of the seafloor during an earthquake Natural sway of intermediate buildings equals the period of vibration of the earthquake

Type of structural failure related to building height
Liquefaction of soils Collapse of higher, intact floors onto ground floors Vertical motions of the seafloor during an earthquake Natural sway of intermediate buildings equals the period of vibration of the earthquake

Results in a tsunami Liquefaction of soils
Collapse of higher, intact floors onto ground floors Vertical motions of the seafloor during an earthquake Natural sway of intermediate buildings equals the period of vibration of the earthquake

Section of an active fault that has not experienced a significant earthquake for a long time
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Rates earthquake intensity
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Wave generated by vertical motions of the seafloor
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Seismic wave that causes the ground to move in two directions
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Forces per unit area acting on a material
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Measure of the energy released by a quake
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Deformation of materials in response to stress
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Fracture in rock along which movement occurs
modified Mercalli scale magnitude stress fault tsunami strain seismic gap surface wave

Most rocks that exist in Earth’s crust are brittle but become ductile at great depths where temperatures are cooler. True False

Seismic belts are relatively narrow and tend to follow tectonic plate boundaries.
True False

If two seismic stations receive data from an earthquake, the quake’s location can be computed if P-waves, S-waves, and surface waves have been received. True False

The fact that a significant earthquake has not occurred within a seismic gap indicates that an earthquake is more likely to occur in the near future. True False

On a seismometer, the suspended mass tends to stay at rest during an earthquake because of inertia.
True False

A seismometer is designed so that its frame vibrates with the movement of the ground.
True False

The amount of damage done to structures as a result of an earthquake is the earthquake’s magnitude.
True False

S-waves are refracted, or bent, by Earth’s outer core.
True False