GEOL Exam 3
Identify the statement that is true about tsunami events.
Tsunamis may be generated by underwater earthquakes, eruptions of island volcanoes, or submarine landslides.
Which of the following statements is true?
Varieties of an element that differ only in the number of neutrons are called isotopes.
Before the development of isotopic dating methods, scientists estimated the age of the Earth by
comparing rates of change on the Earth's surface today with the geologic record.
The boundary surface between two stratigraphic formations is called a
contact
A shield
contains Precambrian metamorphic and igneous rocks outcropping at ground surface.
Mountains are currently forming in all of the following tectonic situations EXCEPT
continental cratons
Signs of mountain building
continental crust thickens, Asthenosphere is compressed, lithospheric mantle sinks lower
A plate boundary where shallow, intermediate, and deep earthquakes all occur is most likely a
convergent-plate boundary.
Which of the following is a method used to determine numerical age?
counting ice bands in a glacier
Which of the following processes most logically explains the different tilts of gravestones in a hillside cemetery?
creep
Which type of mass movement has very slow, but constant movement intimately related to the freeze-thaw cycle?
creep
Curved tree trunks are usually an indication of what kind of mass movement?
creep or solifluction
Which term describes the current theory of earthquake formation?
elastic rebound
Which of the following accurately ranks the subdivisions of geologic time in order from largest to smallest?
eon, era, period, epoch
Put the geologic time segments in order from longest to shortest.
eons, eras, periods, epochs
The point within the Earth at which the rock starts to break and slip on a fault is called the ______ of an earthquake.
epicenter
Which of the following terms best describes the geologic feature depicted in this photo from Arches National Park in Utah?
erosion of a joint set
You should be able to number the events in this figure in the proper order of occurrence. Which of the following events occurred most recently?
erosion of the land surface
If you see small, angular fragments of shattered rock along a linear boundary between two masses of rock, you must be looking at
fault breccia
Which of the following methods for determining the age of materials is a radiometric dating technique?
fission-track analysis
The bare-earth LiDAR imagery showing the Tahoe-Sierra frontal fault zone indicates that this fault is most likely a
dip-slip, normal
The point within the Earth at which the rock starts to break and slip on a fault is called the ______ of an earthquake
focus
Which of the following is NOT a method of numerical dating?
fossil succession
In 1815, William Smith correlated strata from many locations and plotted the information on paper to show the spatial distribution of rock units on the Earth's surface. This document was the first modern
geologic map.
Which of the following earthquake phenomena is the LEAST likely to actually injure or kill humans?
ground shaking
What term is used to identify the length of time it takes for 50% of the parent isotopes to decay to daughter isotopes?
half-life
The Vaiont Dam disaster
happened because a properly engineered dam was built in a geologically unstable location
The East African Rift
has volcanoes along it because asthenosphere is rising under the rift and supplying heat.
Mountains
have roots of continental crust that extend deeper than the level of crust under plains.
Which of the following scenarios would be least likely to produce a mass wasting event?
dry, unconsolidated, irregular gravel with a slope angle of 40°
Which geologic time segment is known as the Age of Dinosaurs?
Mesozoic era
A horizontal line on the Earth's surface has a plunge of
0°
The Richter magnitude scale is logarithmic. Therefore, how much greater is a magnitude 7 earthquake from a magnitude 6?
10x
What is the recurrence interval for the section of the San Andreas fault that runs through Parkfield?
21.8 years
Charcoal (burned wood) that was used to make prehistoric drawings on cave walls in France was scraped off and analyzed. The results showed 4 mg carbon-14 (parent isotope) and 60 mg nitrogen-14 (daughter isotope). The half-life of carbon-14 is 5,730 years. How old are the cave drawings?
22,920 years
A radioactive isotope of the element potassium decays to produce argon. If the ratio of argon to potassium is found to be 7:1, how many half-lives have occurred?
3 half-lives
What is the best estimate for the age of the Earth?
4.56 billion years
Interpret the travel-time curve shown. If the P-wave arrived at Station 2 at 4:43 P.M., approximately when did the earthquake occur?
4:36 pm
Estimate the displacement (amount of slip) on the fault.
5 m
Interpret the travel-time curve shown. How many minutes should there be between the arrival of the first P-wave and the arrival of the first S-wave at Station 2?
5 minutes and 38 seconds
Examining sedimentary bedding in a geologic study reveals that disrupted layers formed 260, 820, 1,200, 2,100, and 2,300 years ago. What is the recurrence interval of the earthquakes that caused the disruption?
510 years
Interpret the travel-time curve shown. How far away is the earthquake epicenter from Station 3?
6000 km
Identify the true statement.
All earthquake magnitude scales are logarithmic, which means that a difference of one unit in magnitude reading represents a 10-fold difference in ground motion.
Mountains formed by continental collision
Appalachian, Alps, Himalayas
Where did the following mass-wasting event take place? A lahar in the Andes buried this town and its inhabitants
Armero, Colombia (1985)
Identify the location of the craton in North America on the image below by selecting the appropriate letter for the location from the dropdown box.
B
Several surfaces between rock layers are identified by letters in this diagram. Which letter correctly identifies an angular unconformity where tilted sedimentary rocks are found beneath flat-lying sedimentary rocks?
B
Which of the following statements about this diagram is true?
Bed 5 (a sandstone) is older than the sill that sits beneath it.
Below is an image of fossils found in an outcrop. A limestone in another outcrop 150 miles away contains fossils C and E. Which bed (labeled 1 through 10 on the image) does this limestone correlate to?
Bed 6
In this illustration,
Block X is the hanging wall.
What is one of the differences between body waves and surface waves?
Body waves are described as compressional or shear.
Which of the following lists fits the order of these three descriptions: Age of Mammals, Age of Dinosaurs, and longest geologic time period.
Cenozoic, Mesozoic, Precambrian
Which of the fossils in this stratigraphic section would be the best index
D
Identify the statement that is true about radiometric dating.
Dating of metamorphic rock tells when the high temperatures of metamorphism cooled below the closure temperatures of the minerals involved.
Where did the following mass-wasting event take place? Quarrying undercut a 600-m-high cliff and triggered a rockfall of over 10 million cubic meters that buried a nearby town and its inhabitants to a depth of 10 to 20 m
Elm, the Swiss Alps (1881)
Identify the true statement
Forest fires followed by heavy rains are likely to result in severe mud and debris flows
If the hillside in this diagram gets wet, which of the following will decrease and likely trigger the block to move?
Fr (resistance force)
Which of the following statements is true?
Governments support the worldwide seismic network because it can detect nuclear bomb tests.
Which of the following puts the orogenies responsible for the Appalachian Mountains in correct chronological order from oldest to youngest?
Grenville, Taconic, Acadian, Alleghanian
Where did the following mass-wasting event take place? A river eroded away the base of the mountain slope it flowed alongside, causing a huge landslide that filled the valley and dammed its flow.
Gros Ventre Slide, Wyoming (1925)
Identify the true statement.
Henri Becquerel discovered principles of radioactivity, which led to the determination of the Earth's age.
Identify the true statement.
In an oblique-slip fault, there's both vertical and horizontal movement along the fault plane.
Identify the true statement.
In the 1985 Mexico City earthquake, high-frequency waves weakened with distance, but unconsolidated sediments beneath the city amplified low-frequency waves.
Identify the true statement.
Isotopic dating can be used only in a closed system, where neither parent material nor daughter material has escaped.
Identify the statement that is true about mass movement.
It becomes possible when strong, intact rock gets weathered
Identify the statement that is true about brittle deformation.
It is a permanent change of shape, while elastic strain is a temporary change of shape.
Identify the true statement.
Major mountain ranges are the result of multiple orogenies over a long geologic time.
Which of the four types of seismic waves are body waves?
P-Waves and S-Waves
Which of the following is true?
Pressure refers to an object feeling the same stress on all sides.
Which of the following lists the four time divisions in order from oldest to youngest?
Proterozoic, Paleozoic, Mesozoic, Cenozoic
Identify the true statement.
R- and L-waves are surface seismic waves.
Which of the four types of seismic waves are surface waves?
R-Waves and L-Waves
Which of the following is NOT a type of energy wave generated by an earthquake?
Radar
Long-term earthquake predictions are based on which of the following?
Recurrence intervals, seismic belts
Which of the following is FALSE?
Rocks break under high pressure.
Why are geologists not able to date sedimentary rocks directly?
Sedimentary rocks are younger than their composite minerals.
Identify the true statement.
Seismic waves become smaller in amplitude with increasing distance from the epicenter.
This illustration shows the conditions that existed just before heavy rains caused the 1925 Gros Ventre Slide in Wyoming. The Gros Ventre Slide occurred as a slump that dammed the Gros Ventre River and created the Lower Slide Lake. Which of the following was primarily responsible for this famous event?
Shale A was responsible for the failure because it was mechanically weak and dipped in a downslope direction
Which of the following statements about stress is true?
Stress that is developed during orogeny can be different at various locations.
This figure illustrates
Strike-slip faulting
A corpse with flesh intact, found in the Alps in 1991, was dated by the carbon-14 method and showed a parent-daughter isotope ratio of approximately 1:1, with slightly more parent material than daughter material. The half-life of carbon-14 is 5,730 years. On the basis of this information, decide which of the following statements is true.
The age could logically be 5,300 years.
Identify the true statement
The angle of repose is the steepest angle at which unconsolidated sediments can sit without slipping downhill
An area of slightly dipping sedimentary rock layers has large inclusions and is intruded by an igneous dike. By applying the basic principles for determining relative ages, decide which of the following is the true statement.
The igneous intrusion (the dike) "baked" (metamorphosed) the sedimentary rock that it touched.
Identify the statement that is true about the 2010 Haiti earthquake.
The likelihood of an earthquake was great because stress had been building on the fault for over 200 years.
The oldest known mineral grain is a 4.4-million-year-old zircon crystal found in an ancient sandstone. Which of the following statements applies to this zircon grain?
The sandstone is younger than 4.4 billion years old.
A hominin (human family) skull was found in a shale layer between two fine-grained igneous rock layers. There were no baked zones on the rocks above the igneous layers. The skull had been 100% fossilized and changed to stone; there was no original skull material left. On the basis of this information, decide which of the following statements is true.
The skull itself cannot be dated, because it is no longer organic material and it is not igneous material. The age of the skull is determined by its position between the igneous layers.
Identify the true statement.
The youngest rocks of a basin are found at its center.
Which of the following is NOT true of P-waves generated by an earthquake?
They are surface waves.
Identify the statement that is true about William Smith's observations.
They revealed that groups of fossil species (fossil assemblages) occurred in limited intervals of strata.
Identify the true statement.
Time zones are set in relation to the time at the astronomical observatory in Greenwich, England.
Where did the following mass-wasting event take place? A layer of rock broke loose along an exfoliation joint and caused damage in a famous recreation area
Yosemite National Park (1996)
A Wadati-Benioff zone is
a band of earthquakes along subducting lithosphere in a convergent boundary.
Which of the following is a way to recognize faults in the field?
a displaced marker bed, such as an ash layer
A mud flow created by the mixing of volcanic ash with meteoric water or melting snow and ice is called
a lahar.
What type of unconformity forms when sedimentary rocks overlie either igneous or metamorphic rocks?
a nonconformity
Infer which of these solids is most likely to deform elastically under stress.
a rubber band
What feature would be considered a plane of weakness within a sequence of sedimentary rocks?
a shale bed
Which of the following would increase the risk of having a landslide?
allowing water to infiltrate the slope
This figure shows
an anticline plunging toward the north.
A different version of an element that has the same number of protons but a different number of neutrons is called
an isotope
A type of fault that occurs when the hanging-wall block moves up and over the footwall block at a steep angle is called a
are a result of plastic deformation.
Long-term earthquake predictions
are based on the recurrence interval and the identification of seismic zones.
The locations of major earthquakes and volcanic eruptions
are usually along plate boundaries.
Which of these are factors that lead to mass movement?
choices 2, 7, and 8 . (2: weathering of minerals to produce clay, 7: removing support at the toe of the slope 8: adding weight at the top of the slope)
Engineered structures for slope stability include all of the following except
barrier island.
Which of the following would result from the same sense of stress and likely be found together?
basins and domes
What type of grains are going to have the steepest angle of repose when piled?
coarse, angular, and dry
Seismometers
can "feel" (or record) large earthquakes that happen on the opposite side of the world.
Uniformitarianism
can be illustrated by scientists' seeing pillow lava forming only underwater, then theorizing that pillow lava found high in the mountains today did nevertheless form underwater.
Avalanches
can be triggered by explosions, people, or even just new snow.
Liquefaction
can cause wet, silty or sandy sediment to turn into an unstable slurry.
Quick clay
can move like a liquid when vibration or shaking separates the water-coated particles
Earthquake prediction is not highly reliable, but geologists do know that
more earthquakes happen along plate boundaries than at intraplate locations.
What type of fault does the figure show?
dip-slip fault, normal
In the diagram shown,
if the half-life of the parent material is 4,000 years, 3 on the horizontal axis of the graph represents 12,000 years.
Mass movement
is a gravity-driven downslope movement of natural materials.
Solifluction
is a kind of creep that is found in high-elevation regions or in the Arctic on slopes that are underlain by permafrost
The San Andreas fault
is a right-lateral, strike-slip fault.
Fault creep
is movement along a fault without an accompanying earthquake.
The Richter scale
is today termed a local magnitude (ML) reading.
When the buoyancy force pushing up on lithosphere equals the gravitational force pulling down on it, the situation is said to show
isostatic equilibrium.
Geologists base their estimate that the Earth is 4.56 billion years old on
isotopic dating of meteorites thought to be from primitive solids of the early Solar System.
The Vaiont Dam area was vulnerable to mass movement because
limestone beds there dipped parallel to the mountain slope and were interlayered with weak shale
Sand volcanoes and sand blows are surface expressions of
liquefaction
Shaking of certain types of wet sediments can cause
liquefaction.
A tsunami
may be just a broad, gentle swelling out at sea but grows as it approaches the shore.
An eroded granite covered by flat-lying sedimentary rocks is an example of a(n)
nonconformity.
The crust in the Basin and Range Province of Nevada, Utah, and Arizona is stretching; therefore, fault movement in this region must be
normal
Which type of structure would most likely form in a rift zone (from extensional stress)?
normal fault
Brittle deformation
occurs when many atomic bonds are broken quickly and rock pieces separate.
Which of the following terms refers to the process of mountain building?
orogeny
Which of the following increases the chances of a mass movement?
raising the water level behind a dam to hold down a potential failure surface
The average time between successive earthquake events along a given fault is called a
recurrence interval.
The initiation of a tsunami by a stick-slip subduction zone is similar to the motion experienced by which type of fault?
reverse fault
A type of fault that occurs when the hanging-wall block moves up and over the footwall block at a steep angle is called a
reverse fault.
This image shows the aftermath of mass movement in a steep-sided glacial valley in Switzerland. This impressive scar and talus pile likely records which of the following types of mass movement?
rockfall
Undercutting of a sea-side cliff will most likely cause what kind of mass movement?
rockfall
This image, showing where large blocks of rock quickly detached from an outcrop and fell straight down onto a roadway, illustrates an example of a
rockfall.
The principle of original continuity says that
sedimentary layers began as continuous expanses of sediment.
Earthquakes in California are
shallow and occur in the upper 15 to 20 km of crust, even though the San Andreas fault cuts through the crust to deeper depths.
You're looking at a fault trace in the field. You observe a polished surface, with linear grooves on it and fine powder along it. In more technical terms, what are you seeing?
slickenside, slip lineation, and fault gouge
Which of the following conditions will tend to make rocks change by plastic (or ductile) deformation rather than by brittle deformation?
slowly applied stress
Slides with a spoon-shaped (concave-up) surface are called
slumps.
This image shows mass movement on a vegetated hillside near the Dietrich River in Alaska. Which of the following terms best describes this type of mass movement?
solifluction
The tragedy in 1970 at Yungay, Peru,
started with an earthquake that triggered an icefall that in turn triggered a debris flow.
What kind of fault is least likely to produce a tsunami?
strike slip fault
A fault moving one block horizontally with respect to the other with no up-and- down motion is called
strike slip.
In this image, we know that sedimentary unit A is older than sedimentary unit B because of the principle of
superposition.
What kind of fold is this?
syncline
Which of the following structures makes a pattern of rock layers on the ground surface that looks like this: parallel stripes, showing bilateral symmetry across a midline (hinge), with rock getting older as you move outward from the hinge.
syncline
Folds that have a trough-shape with limbs that dip toward the hinge are called
synclines
Which of the following is a suitable method of managing snow avalanches?
targeted, controlled explosions
Mountains do not get infinitely high or exist forever, because
the Earth's geothermal gradient is too low.
Using this earthquake hazard map for the United States, determine which area in the list below has the highest earthquake hazard.
the Washington coast
If angle A in this diagram is increased, then
the downslope force (Fd) gets larger
Landslides are likely to happen when
the downslope force becomes greater than the resistance force
If you equate all of the Earth's history to one calendar year, the history of our species (Homo sapiens) would occupy
the last hour before midnight on New Year's Eve.
Nicolas Steno's observations of fossil shark teeth convinced him that
the rock they were in originated as loose sand, not solid rock.
Classification of mass-movement events is based on
the type of material involved (rock, regolith, snow, and ice)
The Badlands of South Dakota are elevated, eroded plateaus and valleys composed of undeformed sedimentary strata. These are not mountains, because
there's no deformation of rock structure
This satellite image shows the Himalaya Mountains, the tallest mountain range on Earth, and the Tibet Plateau. Which of the following processes is responsible for the formation of the mountains in this region?
thickening of the crust caused by deformation during collision
Underwater avalanches of suspended sediments are called
turbidity currents.
Which of the following is not a slope stabilization technique?
undercutting
"The present is the key to the past" best describes the principle of
uniformitarianism.
What is the overall rate of growth of the Himalayas per year?
uplift at 17 mm per year
The tsunami event of December 26, 2004,
was first noticed as a withdrawal of the sea along the beach front.
Which of the following is a good technique for building earthquake-resistant structures?
wrapping bridge supports with steel cables
