ES 10: The Earth
Practice Final Exam 1998 Answers
This practice final exam is drawn from a large set of final exam questions
which are mostly based on the book and lectures, with only a few from other
sources (such as the beach walk). Since it's drawn from the large set, it
is likely to be very similar to the final exam. You can use it as a study
guide to see what the exam might be like, but to do well on the final (which
is 50% of your grade in ES 10) you will need to read through your lecture
notes and the pages of the book noted on the
Final Exam section of the exams page.
As on the real exam, when you read this practice exam, make sure to read each
question completely and carefully. We've had people do poorly in the past
because they merely skimmed the questions.
The correct answers are in bold face.
Choose the BEST and most CORRECT answer from the choices given after each
- Why don't continents subduct?
- they do not encounter subduction zones
- they are too old and cold to subduct
- they are too young and hot to subduct
- their crust is too thick and buoyant to subduct
- Suppose you mapped a major fault and wanted to know its history of
earthquakes for the past 10,000 years. You would:
- examine the earthquake catalogues
- date the ages of trees that had fallen in past earthquakes
- dig a trench across the fault and look for breaks in the
- none of the above
- Where did the rounded cobbles on the beach (on the Beach Walk)
- longshore current
- dump trucks loads to stabilize beach
- fell from nearby cliff
- breakup of larger boulders by El Nino surf
- The chemical composition of the Earth's crust is
- about the same as that of the Sun.
- about the same as that of the mantle.
- typical of the overall composition of the Earth.
- None of these is true.
- Nuclear fusion
- converts some of the mass of an atom into energy.
- has only been achieved in an uncontrolled manner (in hydrogen
bombs) on Earth.
- represents a potentially limitless energy source for society, if
it can be achieved under controlled conditions.
- All of these are true.
- The asthenosphere
- is a zone of anomalously low seismic velocity.
- underlies the lithosphere.
- is a zone of plastic deformation within the upper part of the
- All of these are true.
- The rock cycle
- is more important now than ever before in Earth history.
- does not involve the biosphere or the atmosphere, only the solid
Earth and the hydrosphere.
- describes the processes whereby the internal activities of the
solid Earth interact with external activities involving the
hydrosphere, biosphere, and atmosphere.
- operates independently of the process of plate tectonics.
- The hardest mineral is
- Crater Lake, Oregon, occupies the ____________ left by the prehistoric
eruption of Mount Mazama.
- volcanic neck
- volcanic vent
- tephra cone
- Which one of the following does not belong with the others?
- convergent margin
- island arc
- spreading center
- Midocean ridges define
- convergent plate boundaries.
- shear plate boundaries.
- divergent plate boundaries.
- All of these are true.
- The number of large lithospheric plates is
- about twenty.
- too many to count.
- Which one of the following statements is false?
- The midocean spreading ridge environment, although
characterized by volcanism, is mainly aseismic (non-seismic).
- Most deep-focus earthquakes are located along convergent plate
- The majority of circum-Pacific area earthquakes are associated
with the process of subduction.
- The Pacific Plate, on the west side of the San Andreas Fault,
is moving roughly northwards relative to the North American
Plate, on the east side of the fault.
- The principle of stratigraphic superposition states that:
- in any sequence of undisturbed sedimentary strata, the order in
which the strata were deposited is from the bottom to the top.
- older strata are deformed and truncated by erosion before younger
strata are deposited across them.
- tectonics, erosion, and sedimentation are all closely related.
- sediments are deposited in strata that are horizontal, or nearly
so, and parallel to the Earth's surface.
- A modern example of a plate triple junction is found in the area of
- the Red Sea and the Gulf of Aden.
- the Aleutian Islands.
- the Canadian Shield.
- the Andean coast of South America.
- The periodic climatic variation in which tradewinds slacken and surface
waters of the central and eastern Pacific become anomalously warm is
- El Niño/Southern Oscillation.
- thermohaline circulation.
- geostrophic flow.
- Ekman transport.
- Sea levels fluctuate as a result of
- changes in water volume due to the waxing and waning of
- changes in ocean-basin volume as lithospheric plates shift their
- tidal forces.
- All of these are true.
- A good aquifer is typically
- porous but not permeable.
- permeable but not porous.
- porous and permeable.
- dependent on grain size.
- The rate at which natural processes are removing carbon dioxide from
the atmosphere is _____________ the rate at which human activities
are adding it.
- slower than
- faster than
- approximately the same as
- not comparable to
- Which one of the following is not one of the changes that scientists
predict will be associated with global climatic warming?
- shifting of forest boundaries in response to altered temperature
and precipitation patterns
- global decrease in sea levels due to excess evaporation
- increased droughts in some midcontinental agricultural regions
- All of these are changes that scientists predict will be
associated with global climatic warming.
- The glassy texture observed in obsidian is due to:
- the presence of only one crystal in the rock
- cooling over a long period of time during which the atoms
actually break down and lose any order they had when the rock
- alternating cooling and heating of the rock in the subsurface
- super rapid cooling such as that experienced when magma is
ejected from a volcano
- The portion of the conterminous United States that is most likely to
have a volcanic eruption in the near future is:
- New England
- the Pacific Northwest
- central Kansas
- the coastline along Florida and Georgia
- The Hawaiian Islands formed because:
- the Pacific Plate moved over a hot spot
- mid-oceanic basalts erupted and reached the surface of the water
- pyroclastic debris built up to reach sea level
- a series of composite cones were produced by subduction
- Sediments composed of broken fragments of preexisting rocks and
minerals are termed:
- clastic or fragmental
- The longshore drift of sand is due to:
- rip currents
- the backwash of the waves
- the incoming rush of the waves
- the angle of incidence waves have with the beach
- The rate of seafloor spreading
- is uniform along the entire length of the spreading center.
- cannot be measured.
- is such that the ocean floors contain no rocks older than
about 200 million years.
- is greater in deeper water.
- The movement of the Pacific Plate past the North American Plate along
the San Andreas fault is an example of what type of plate boundary?
- convergent continent/continent collision
- convergent, ocean/continent collision
- Continent/continent plate collisions are:
- a major producer of folded mountain ranges worldwide
- characterized by many deep-focus earthquakes that occur each year
- responsible for the formation of massive deposits of basalt on
the Earth's surface
- best associated with divergent plate boundaries
- An area that experiences only shallow earthquakes is:
- the west coast of South America
- southern Alaska
- the mid-Atlantic ridge
- none of these as they all have deep focus earthquakes
- Lithosphere is created at spreading ridges. Where is it destroyed?
- transform faults
- the earth grows in radius
- deep ocean trenches
- hot spots
- What is the speed of a seismic shear wave in the ocean?
- 1500 m/s
- 0 m/s
- it is related to ocean depth
- 835 km/hour
- What is the best way to scientifically explain the thousands of feet
of coral limestone beneath most atolls?
- sea level has fallen thousands of feet since the reef began to
- the eroded volcano below the limestone rose thousands of feet
after the limestone accumulated
- the eroded volcano slowly sank as sea level remained steady or
- the volcano never reached the surface, allowing a very thick cap
of coral limestones to accumulate
- Which two statements concerning the earth's magnetic field are true?
- during geologic time, the magnetic and geographic rotational
poles have always been close together
- the magnetic field has become stronger over geologic time as
more iron solidifies inside the inner core
- the magnetic field changes rapidly, geologically speaking, and
the field has changed polarity many times
- the field originates in the lithosphere because the deeper rocks
are too hot to be magnetic
- The asthenosphere can be described as:
- being composed of partially molten rock and supporting the
- having a solid inner core
- being strong and riding atop the asthenosphere
- being composed of crust some 4.6 billion years old
- We know the Earth's core is made of iron because:
- the outer core does not transmit shear waves
- of analysis of solar spectra and meteorites
- there is a seismic shadow zone
- of satellite gravity measurements
- Deep-focus earthquakes (more than 200 km deep) are associated with
only one type of plate boundary. Which is it?
- convergent, subduction
- divergent, seafloor spreading
- transform, plates sliding past one another
- What is the radius of the Earth?
- 29 km
- 290 km
- 2900 km
- 6400 km
- Deep ocean trenches are most abundant around the rim of which ocean
- Which features show where oceanic lithosphere sinks downward into the
- deep-ocean trenches
- submarine canyons
- abyssal seamounts
- mid-ocean ridges
- Which are not associated with mid-ocean ridge systems?
- submarine hot springs
- submarine basaltic flows
- areas of cool old lithosphere
- axial rift valleys
- Which one most completely outlines the edges of the lithospheric
- the locations of earthquake epicenters
- the edges of the continental shelves
- the locations of deep mantle hot spots
- the locations of active stratovolcanoes
- Which source of energy drives mantle convection and plate motions?
- the Earth's thermal energy derived from radiogenic heating
and residual heat from the Earth's formation
- solar heating of the Earth's crust
- gravitational energy of the Sun-Earth and Moon-Earth systems
- the intergalatic, nebular force-field
- The age of the Earth accepted by scientists today is what ?
- 6.4 billion years
- 4.6 billion years
- 4.6 million years
- 6.4 million years
You need to know the names of the major plates. Fill them in on the map
Tue Mar 10 10:39:52 PST 1998