Geology 1400 - earthquake
Slab pull occurs because subducting slabs are _________, and therefore are _________ dense than the surrounding asthenosphere.
cooler; more
Normal, reverse, and thrust are all examples of ____________ faults.
dip-slip
Which basic type of plate boundary is shown in the image below?
divergent
The distribution of _________ around the globe provides the primary indicator of the boundaries between lithospheric plates.
earthquakes
Which of the following is a type of convergent plate boundary?
subduction zone
In the image below, the rocks have been bent into an elongate trough. This is a(n) ________.
syncline
In plate tectonics, a triple junction is a place on the earths surface where
the boundaries of three lithospheric plates meet at a single point.
Hypocenter
the underground focus point of an earthquake.
Mid-ocean ridges are
underwater volcanic mountain ranges
Tsunamis are most commonly generated by sudden _________ movement of the seafloor during an earthquake.
vertical
Seismic retrofitting is the process of
strengthening existing buildings and structures.
Lithospheric plates move relative to other along plate boundaries at velocities between _________
1 and 20 centimeters per year
According to the moment magnitude scale (Mw), the amplitude of ground shaking during a magnitude 8 earthquake would be 1,000 times greater than a magnitude ________ earthquake.
5
A tsunami is
A seawave generated by an earthquake, landslide, or submarine volcanic eruption that may destroy coastal cities thousands of kilometers from its source
Who first proposed the theory of continental drift?
Alfred Wegener
___________ propose the continental- drift hypothesis, suggesting that the arrangement of continents on the planet has changed over geologic time.
Alfred wegener
Sea floor spreading is associated volcanic activity
Along mid-ocean ridges.
In the image below, the rocks have been bent into and elongate arch. This is an example of a(n)___________.
Anticline
The majority of new oceanic crust is created
At mid-ocean ridges.
Most of the polling force driving plate motion is produced
At subduction zones.
The graph below shows the change in velocity of seismic waves depth in the crust. Why does the velocity of the P-wave drop drastically at the core-mantle boundary?
Because the outer core is liquid and seismic waves travel slower in liquids
Sort-term predictions of earthquake behavior have
Been largely unreliable
Continental lithisphere does not subduct because it is too
Buoyant.
Mountain ridges formed along production zones are formed, in part, by__________ in the crust.
Compression
As shown in the figure below, a coil spring would be useful in illustrating any _________wave.
Compressional
Large, thick-crusted, nonvolcanic mountain belts, like the Himalayas, are associated with
Continent-continent collisions.
Which concept/Hypothesis was developed first?
Continental drift
Which of the following is true of continental lithosphere compared to oceanic lithosphere?
Continental lithosphere is thicker than oceanic lithosphere.
A ____________ is a linear feature in Continental lithosphere where a plate is pulling apart, resulting in a deep Valley, extensive faulting and volcanism, if substained, division into two plates separated by a new oceanic lithosphere
Continental rift
Most medium- and deep-focus earthquakes occur at
Convergent-plate boundaries
Which of the following is true about the lithosphere?
It is composed of a crust and the uppermost rigid part of the mantle.
Designing and retrofitting building to withstand The effects of earthquakes is a type of
Earthquake engineering.
Add transformation plate boundaries,
Earthquakes are common but volcanoes are absent.
The point in the earths surface directly above the point where the earthquake occurs as termed
Epicenter.
At the subduction zone where the Pacific plate is abducting under the islands of Japan, the Wadati-Benioff is deep earthquakes
Extends from the trench westward underneath Japan
Movements along faults often produces a rock formed from sharply angled rock fragments termed __________.
Fault breccia
The distinction between joints and faults is that_______.
Faults are fractures along which displacement has occurred; displacement does not occur along joints
The idea that the continents had once fit together as a simple supercontinent called Pangaea was rejected when first proposed because.
Geologist did not know of a force great enough to move continents.
At any point along the surface of any non-vertical fall, as is shown in the figure below, the
Hanging wall lies vertically above the footwall.
The portion along a fold where curvature is the greatest and termed the fold __________.
Hinge
Hotspots are caused by
Hot plumes of mantle that rise up through cooler, denser surrounding rock.
The point within the earth where the earthquake originates is termed the
Hypocenter (focus).
With increasing distance of mid ocean ridge, the age of oceanic crust
Increases.
____________ is the balance between the Weight of the mountain range and booyancy provided by the underlying mantle.
Isostasy
It's a P-wave is traveling through the earth and encounters the molten magma chamber, what will happen to the velocity of the P-wave?
It will decrease.
If an S-wave is traveling through rock win it encounters a mountain magnet chamber, what will happen to the velocity of the S-wave?
It will not travel through the magma.
Marine magnetic anomalies in oceanic crust result from sea floor spreading in conjunction with
Magnetic polarity reversals
Which earthquake scale is used to assess the effects of an earthquake on humans and human-made structures
Mercalli scale
Which of the following is a divergent plate boundary?
Mid-Atlantic Ridge
Marine magnetic anomaly belts run parallel to
Mid-ocean ridges.
Which of these properly illustrates the principal of isostasy?
Mountains stand high because they are gravitationally balanced by there deep crustal roots.
During an earthquake, if a hanging wall slides down words relative to a foot wall, The fall is termed a ________ fault. Refer to the figure below for an example of such a feature.
Normal
In a __________ fault, the fault plane is non-vertical and the hanging wall block moves downward relative to the foot wall block.
Normal
What type of a fault is the result of deformation to accommodate tensile stresses such as those that occur during rifting?
Normal
What kind of fault is shown in the image below?
Normal fault
Which type of seismic wave has the fastest velocity?
P-wave
What is the correct order of arrival for seismic waves?
P-wave, S-waves, surface waves
Magnetic strips on the sea floor are roughly _________ about the ridge access along which they were created.
Parallel to and symmetric
According to the theory of plate tectonics, plates are
Pieces of lithosphere that move over the surface of the earth with respect to one another.
Epicenter
Point on Earth's surface directly above an earthquake's focus
Which is not one of the ideas that A. Werner used to support his theory of continental drift?
Polar wander from paleomagnetism
During an earthquake, if the hanging glass slides upwards relative to the football, the fall is termed a _________ fa if the fault is steep (closer to vertical than horizontal). Refer to the figure below for an example of such a feature.
Reverse
If a fault plane is greater than 30° from horizontal and then hanging wall block moves upward relative to the foot wall block, the fault is called a ________ fault.
Reverse
What kind of fault is shown in the image below?
Reverse fault
What type of fault is illustrated in the figure to the left?
Right lateral strike slip
In the following graph, why does the line of S-wave not appear in the outer core?
S-waves can't travel the outer core because it is liquid.
Which of the following best describes how scientist study the interior of the earth?
Scientist use seimic waves, gravity, and magnetism to study the earth's interior.
Which of the following best describes how scientist study the interior of the earth?
Scientists use seismic waves, gravity, and magnetism to study the earths interior.
What kind of process is shown in the image below?
Sea floor spreading
A _________ is a scientific insurance used to record the ground motions produced by an earthquake.
Seismometer
What kind of stress is associated with the fault shown in the figure above?
Shear
On either side of the mid-ocean ridge, Oceanic lithosphere slowly_________
Sinks into the atmosphere because it cools and thickens, increasing in density.
What is the most important driving force for the plates in plate tectonics?
Slab pull
Periods of intermittent sliding on a fault because of stress released during episodes of slip, followed by stress buildup on the point that the fault is reactivated, are termed
Stick-slip behavior
How is stress different from strain?
Strain is the change in shape of a rock due to applied stress.
How is stress different from force?
Stress is the force applied per unit area.
We can describe the orientation of planar features such as faults and joints using measurement of the ________.
Strike and dip
If a fall is nearly vertical in orientation and the two walls of rock on opposite sides slide past one another horizontally, the phone is termed a _________fault. Refer to the figure below for an example of such a feature.
Strike-slip
The only place where we can have deep earthquakes is where?
Subduction zone
Deep-sea trenches are likely to be located near
Subduction zones.
Earthquake waves that travel along the earth's surface are termed.
Surface waves.
What kind of fold is shown in the picture below?
Syncline
Oceanic lithosphere thickens as it moves away from mid-ocean ridges primarily because of
The addition of new lithospheric mantle as a result of cooling
In a hot-spot volcanic island chain, such as the Hawaiian islands, which of the following is true?
The ages and distance between volcanoes can be used to calculate plate velocities.
The map below depicts the locations of earthquakes in the ocean basins. Which of the following locations is most likely to be located along a plate boundary?
The middle of the north Atlantic ocean, where there is north-south belt of earthquakes
A long delay the arrival of p-waves and s-waves at a seismometer means that
The seismometer is located far from the earthquake.
What can be said about the ocean sediments collected from location B as compared to location D?
They are thicker and older
Which of the following best describes the distribution of earthquakes around the globe?
They occur in distinct zones.
Which of the following is a conservative plate boundary?
Transform
The time it takes for seismic wave to travel from the focus of an earthquake to a seismometer is called the _________.
Travel time
Earthquakes that occur in a band called the ________ can be used to track the motion of subducted oceanic lithosphere.
Wadait-Benioff zone
Faults that have moved recently or are likely to move in the future are referred to as ____________ faults.
active
The vast majority of earthquakes occur
along any plate boundary.
The rock produced at mid-ocean ridges consists of
basalt at shallow depths and gabbro at deeper depths.
On a geologic map, if the contacts between sedimentary rock units form a bull's-eye pattern of concentric circles, with the youngest unit in the center, the underlying structure is a(n) ________.
basin
Body waves include
both S- and P-waves
Faulting and earthquakes are examples of what type of deformation?
brittle
Subduction zones are found at _____________ plate boundaries.
convergent
Before an earthquake, the rocks can respond to applied stress to a small degree by bending and warping without breaking. This is termed _________.
elastic behavior
Seismic waves travel _________ in solids than in liquids; however, unlike P-waves, S-waves __________ travel through liquids.
faster; can't
At a subduction zone, the downgoing (subducting) plate
is always composed of oceanic lithosphere
If you stand on one side of a strike-slip fault and the block on the other side of the fault has moved to your left, this is known as a(n) ________.
left lateral fault
The sides of a fold, where curvature is at a minimum, are termed _________.
limbs
Wet and unconsolidated substrates are uniquely susceptible to ________ during an earthquake.
liquefaction
Aftershocks after a major earthquake
may continue for days, weeks, or years after the initial earthquake.
Most earthquake are a result of
movement of rocks along faults.
If compressive stresses acting on a rock are greatest in a north-south direction, the rock will likely deform by shortening in a _________ direction.
north-south
Transform plate boundaries are unlike other plate boundaries because
old plate is not consumed nor is new plate created.
On a geologic map, the beds of an eroded anticline will be _________ near the fold hinge compared to further from the hinge.
older
An episode of mountain building is termed a(n) ____________.
orogeny
Continental coastlines that occur within the interior of a lithospheric plate are called ________ margins.
passive
Surface waves
produce most of the damage to buildings during earthquakes.
The average length of time between earthquakes along a fault is termed the __________
recurrence interval
The energy that is released during an earthquake travels through the earth as vibrations termed _________.
seismic waves
A body of rock affected by compressive stress will likely undergo ____________.
shortening
The core consists of two layers: a(n) ________ inner core and a(n) ________ outer core.
solid; liquid
Which of the following is NOT associated with convergent plate boundaries?
spreading centers
The term for a change in shape induced by a stress is _________.
strain
The term for a change in shape induced by stress is ________.
strain
Which of the following is NOT an example of deformation?
stratification