Geology Exam 3 Review
Which of the following events allows rocks on either side of a fault to rebound elastically, causing an earthquake?
Friction along the fault plane is overcome
The primary earthquake hazard that caused the collapse of elevated highways int he kobe, Japan Earthquake was _____ ______
Ground Shaking
The basin and Range province, bounded on the east by the Wasatch Range and on the west by the Sierra Nevada Mountains, is being formed by what tectonic force?
horizontal extension
_____ is a secondary earthquake hazard caused by ground shaking which transforms stable, unconsolidated, water-saturated sand and silt into a mobile fluid, where soil loses bearing capacity resulting in tilted/sinking structures and ground storage tanks popping to the surface
liquefaction
Where in Chile did the magnitude 8.2 earthquake strike in 2014
off the coast of northern chile near the town of iquique
How long does it typically take for the first earthquake waves to arrive at a seismograph that is some distance away from the epicenter after the earthquake occurs
several minutes
_____ is defined as that which changes the shape or size of a rock body
strain
______ is defined as force applied to a given area
stress
Which of the following best describes liquefaction
the transformation of stable soil into loose, liquefied material that is able to rise toward Earth's surface.
In addition to a travel-time graph, at least how many seismograph stations are needed to determine the location of the epicenter of an earthquake?
three
Deep-focus earthquakes occur along _____ plate boundaries, where subduction occurs
Convergent
What type of plate boundary are most tsunamis associated with?
Convergent plate boundaries
When a fault is expressed at the surface, it is called a _____
Fault scarp
Most earthquakes are the result of movement along which of the following features?
Faults
_____ are fractures in rocks, along which appreciable displacement has taken place
Faults
The Point within Earth from which earthquake wave energy radiates is known by which of the following terms?
Focus
______ are structures with wave-like undulations created during crustal deformatin at great depths over a long period of geologic time
Folds
The four main factors that affect rock strength include temperature, confining pressure, time and _____ _____
Rock type
Richter magnitude is derived from measuring ______ and _____ and then plotting them on a Richter diagram
S minus P wave time; Maximum S wave height
The Primary earthquake hazard that forms visible fault scarps and occurs in Magnitude 6.5 or larger events is called a _____
Surface fault rupture
Which of the following correctly compares the seismograph readings from Station 1 to Station 2 as shown in the video?
Surface waves show smaller amplitude at station 2.
A ______ plate boundary is associated with the San Andreas Fault
Transform
changes in p waves velocities and increased radon activity are physical precursors for many earthquakes
True
Why do ships at sea tend not to notice tsunamis
Tsunamis in deep water have small wave height and long wavelength
The _____ Zone is a zone of increasing earthquake-foci depths away from the trench
Wadari Benioff
The names primary and secondary refer to_______
Wave speed
what is the name of the Wasatch fault segment that is located along the eastern extent of the WSU campus
Weber fault segment
Which of the following is a characteristic of an S wave?
"shaking" particle motion at right angles to the direction of wave travel
On average, how many damaging earthquakes occur each year?
1000
The average recurrence interval for individual fault segments for the central five segments is _____
1200-2400
The composite recurrence interval for the five central fault segments along the wasatch range is approximately ____ years
300-400
Shallow-focus earthquakes occur at depths less than ____ km
70
What was the moment magnitude and duration of the 1964 alask earthquake, which is the largest recorded earthquake in North America?
9.2 and 3-4 minutes
The bend in the stone walls int he town of Hollister, California are a result of ______
A fault creep along the calaveras Fault
What causes an earthquake such as the one that occurred in san francisco in 1906
A plates move, stress builds up at the boundary. When the boundary eventually snaps, energy is released as an earthquake
Define earthquake intensity
A qualitative measure of the amount of ground shaking at a certain location
What is a tsunami
A series of water waves that travel away from a fault in all directions at high speed
How did the earthquake affect major economic activities of northern Chile
Although major copper mining operations are nearby, they were unaffected by the earthquake
Describe how sand volvanoes form
An earthquake causes loose, saturated sandy material to liquefy, shoot upward through fractures of a confining unit, and eventually erupt at the surface.
What is a seismograph
An instrument used to record earthquake waves
An______ is a fold structure produced by compressional stress and when eroded on the Earths surface, has the oldest rocks along the axial plane of the fold, with rocks becoming progressively younger as you walk perpendicular away from the axial plane towards the limbs of the fold
Anticline
If the stress applied to the rock is greater than rock strength, what happens?
Blocks of rock will slide relatice to one another along fault, causing an earthquake
A smaller earthquake in Virginia was felt over a larger distance, as compared to a larger earthquake in California. What is a reason this occurred?
Colder Crust
What best describes the movement of P waves?
Compression and Expansion
______ are natural phenomena caused by violent motion of the ground that occurs when a large volume of rock being stressed suddenly ruptures along a new or pre-existing fault
Earthquake
____ and ____ are two pieces of information used to develop long-term earthquake forecasts in the form of recurrence intervals
Elastic Rebound Model Paleoseismic evidence
How are elastic rebound and elastic deformation different?
Elastic deformation causes objects to bend, whereas rebound causes objects to return to their original shape.
The theory describing the mechanism for earthquake generation stating that rocks deformed by tectonic forces store elastic energy. When frictional resistance is overcome and rupture occurs, the deformed rock returns to its original shape
Elastic rebound
The ______ is the geographic point on the Earths surface directly above the rupture location
Epicenter
Fault surface displacement is most commonly known as fault gouge
False
Seismologists can accurately make short range predictions of earthquake location and magnitude consistently within days or hours
False
The WSU campus is located on the dounthrown side of the Weber segment of the Wasatch Fault Zone. This is a Normal Fault. What type of fault block does the WSU campus sit
Hanging wall
The name of the site where slippage begins and earthquake waves radiate outward is called the______
Hypocenter
Why does the wave height of a tsunami increase as the tsunami enters shallow water
In shallow water, the energy of the tsunami must be contained withing a smaller water column
The _________ is the northerly trending zone of noticeable seismic activity that extends in a curved pattern from southern Nevada and northern Arizona into northwestern Montana.
Intermountain Seismic Belt
Earths outer layer is composed of seven dominant plates. What is the name of this rigid outer layer?
Lithosphere
Structures built on______ will become unstable during an earthquake.
Loose, Saturated sediments
______ Waves are a form of surface wave that cause the most damage because they shake the ground from side to side at right angles to travel path, damaging structural foundations. Have the highest horizontal wave amplitudes.
Love
Why is moment magnitude preferred over Richter magnitude?
Moment magnitude measures the total energy released during an earthquake and can adequately measure the energy of large earthquakes.
The last major earthquake to occur on one of the central five fault segments was 350 years ago. what segment ruptured from this event?
Nephi
List the 3 major types of faults
Normal, reverse, strike slip
Which type of plate boundary is most often associated with these earthquake events
Ocean-continent convergent boundaries
Which of the following might be seen were strike-slip movement has occurred?
Offset fences
As the distance between the epicenter of an earthquake and a seismograph station increases, so does the difference in the arrival times of the P and S waves, what causes this?
P waves are faster than S waves
Based strictly on velocity alone, which type of seismic wave would arrive at a seismograph station first P, S, Surface, Sonic?
P-wave or Primary wave
Which ocean is associated with most tsunamis
Pacific
Which statement provides the best explanation of why most earthquakes occur at plate boundaries?
Plate boundaries are locations on Earth where portions of the lithosphere interact as they move past each other
What type of plate interaction produces the San Andreas Fault
Plates sliding past one another
Surface fault rupture, tectonic deformation and ground shaking are examples of _____ earthquake hazards, directly caused by the seismic event
Primary
_____ waves that travel with a push-pull motion. changing the volume of the intervening material. Can travel through solids, liquids and gases
Primary
______Faulting is associated with the portion of the Juan de Fuca plate Boundary that is being subducted specifically under the North American Plate?
Reverse
What principal direction is the relatice displacement along the San Andreas Fault?
Right-Lateral
The offset of Wallace creek is caused by ______
Right-lateral movement along the San Andreas strike-slip fault
_____ waves shake particles at right angles to the direction of wave travel temporarily change the shape of the material that transmits them. Do not travel through liquids or gases. Moves through the Earths Mass
Secondary
Landslides are an example of a _____ earthquake hazard, caused by ground shaking
Secondary or Teritiary
Which sediment below would have the highest cohesive strength during an earthquake?
Sediment with many contact points between grains and air in pore spaces
____ are a secondary earthquake hazard that occur in enclosed water basins like the Great Salt Lake and are cause by ground shaking from great earthquakes. The rhythmic sloshing of water can cause flooding due to wave run-up onshore and by weakening earthen dams, resulting in failure
Seiches
_____ are inactive seismic zones in active earthquake regions that are storing strain for future major earthquakes. These zones are considered overdue for an earthquake
Seismic Gaps
The instuments that record seismic waves by suspending a stationary mass that does not move due to inertia with ground motion
Seismograph
During the 1906 San Francisco Earthquake, the Pacific Plate moved 4.7 meters north relative to the North American Plate. Which of the following types of stress was exerted on the rocks during this earthquake?
Shear Stress
A ______ Tectonic force causes the rupture and displacement along the San Andreas Fault
Shearing
What location of a great earthquake in 1556 is considered to be possibly the greatest natural disaster ever with 830,000 estimated deaths?
Shensi China
Which of the following describes the type of deformation experienced by rocks before an earthquake?
Slow deformation
Elastic deformation before an earthquake is like____, whereas rupture is like____.
Stretching a rubber band, breaking a rubber band
The primary earthquake hazard that resulted in a partially inundated road along the shore of Middle Bay, Kodiak Island as well as ground uplift in other parts of southern Alaska after the 1964 Alaska earthquake is ____ ____
Tectonic Deformation
What was the response of the Chilean government to the earthquake?
The chilean government quickly evacuated low-lying areas and declared states of emergency
What will happen to a straight fence that undergoes elastic strain during an earthquake
The fence will bend in the direction of stress
Which of the following responses best describes the epicenter of an earthquake?
The point on Earths Surface directly above the focus of an earthquake
How desructive was the tsunami generated by the earthquake?
The tsunami was approximately two meters high and destroyed some fishing boats
What was the human impact of the earthquake?
There were fewer than 10 deaths but almost 1 million people evacuated their homes
The crust becomes _____ and _____ when tensional forces are applied over a long period of geologic time
Thinner and Longer
Will Sumatra experience another tsunami like the destructive one of December 2004?
This is likely, because Sumatra is near many ocean trenches
How are tsunamis generated
Through displacement of the seafloor under water
____ in the sandy layer causes the ground to subside after sand volvanoes form
Tighter Packing
what is the underlying principle of seismograph construction
a heavy weight suspended within a moving box needs to overcome inertia, resulting in a slight delay int he motion of the weight after the box moves
When will the first earthquake waves arrive at a seismograph station
a short time after the earthquake occurs
_____ waves travel through the earths interior
body
The hanging wall moves ____ relative to the footwall in a _____ fault
down, normal
Tertiary earthquake hazard commonly caused by surface fault rupture that severs gas and electrical lines as well as water lines making it difficult to mitigate the hazard
fire
Amongst all seismic waves, surface waves______
have the slowest velocity