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ES 10 -- The Earth
Final Exam -- Practice Version
12 March 1997
- What is a typical rate for seafloor spreading?
- 50 m/yr
- 5 m/yr
- 50 mm/yr
- 0 mm/yr
- What causes ocean tides?
- gravitational pull of the sun
- gravitational pull of the moon
- distribution of continents
- gravitational pull of the sun and moon
- Which of these igneous rocks has the highest silica content?
- diorite
- andesite
- granite
- basalt
- What is a guyot?
- flat-topped seamount
- low-lying coral-reef island
- type of rock
- small seamount
- What type of plate boundary is the San Andreas Fault?
- subduction zone
- spreading ridge
- transform fault
- fracture zone
- What is the average elevation of the continents?
- 8 m
- 80 m
- 800 m
- 8000 m
- What is the average thickness of the oceanic crust?
- 7 km
- 70 km
- 700 km
- 7000 km
- The speed of sound in sea water is 1500 m/sec. What is the round-trip
time of a sound pulse when the water depth is 3000 m?
- 1 s
- 2 s
- 4 s
- 8 s
- Where is the largest ice cap?
- Iceland
- Greenland
- Antarctica
- Australia
- What are the units of mass density?
- m/s
- tree/acre
- w/m2
- kg/m3
- Where do the deepest earthquakes occur?
- San Francisco
- the core
- subduction zone
- transform faults
- Lithosphere is created at spreading ridges. Where is it destroyed?
- transform faults
- hot spots
- deep ocean trenches
- No, it is not destroyed. The earth grows in radius.
- Which type of plate boundary has mostly strike-slip faults?
- spreading ridge
- continental margin
- transform fault
- subduction zone
- Which have the greatest velocities in rock?
- surface waves
- tsunami
- primary waves (P-waves)
- secondary waves (S-waves)
- Which currents move sand and water parallel to the beach?
- reflected
- translational
- longshore
- ebb tide
- Which would prove that a coastline was emergent?
- many bedrock islands
- an elevated wave-cut terrace
- a barrier island
- an estuary
- What famous 19th century scientist
proposed a basically correct theory of how atolls formed?
- Newton
- Hutton
- Darwin
- Lyell
- What is the best way to scientifically explain the hundreds of meters
of coral limestone beneath most atolls?
- sea level has fallen thousands of feet since the reef began to
grow
- 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
rose gradually
- the volcano never reached the surface, allowing a very thick cap
of coral limestones to accumulate
- On a typical seismogram, which waves will show the highest amplitudes?
- P waves
- S waves
- surface waves
- body waves
- The Marina District in San Francisco was heavily damaged in the 1906
and 1989 quakes. Why?
- the epicenters of both quakes were right under the district
- the area is built on consolidated rock, causing the shaking to
be amplified
- liquefaction and other foundation failures were common
- shaking was not any more extensive than elsewhere in the city,
but the whole district burned following each quake
- During the glacial period, sea level:
- rises
- falls
- remains at the same level
- The oldest basalts of the oceanic crust are approximately 160 million
years old. Where would you go to drill samples of these old oceanic
basalts?
- at the crest of the East Pacific mid-ocean ridge
- on the oceanic side of the Mariana deep ocean trench
- under Iceland
- off the coast of our nation's capital (Washington, D.C.)
- What does NOT happen as the oceanic lithosphere ages?
- seafloor depth increases
- lithospheric thickness increases
- magnetic anomaly increases
- sediments accumulate on the seafloor
- How do we know that the Rose Canyon Fault has ruptured during the past
10,000 years?
- earthquakes are common along the fault today
- a trench across the fault shows offsets in sedimentary layers
- the fault follows Interstate 5
- all faults in California are active
- How many seismic stations are needed to locate an earthquake?
- 1
- 2
- at least 3
- at least 10
- What is the circumference of the Earth
(i.e. 2
times the radius, where
= 3.14)?
- 400 km
- 4,000 km
- 40,000 km
- 400,000 km
- These tides create the largest daily tidal range.
- spring tides
- solar tides
- neap tides
- lunar tides
- Which of the following is a depositional feature?
- wave-cut cliffs
- sea stack
- spit
- sea arch
- _______ is a deposit which formed by the downslope movement of dense,
sediment-laden water. It exhibits graded bedding and is found in
submarine canyons.
- turbidite
- conglomerate
- ophiolite
- terrigenous sediment
- What was Pangaea? When did it form and when did it break apart?
- a supersize ocean basin that opened in the Triassic and closed
in the Palaeocene
- a supersize Precambrian shield area of Africa and South America
that broke apart early in the Proterozic
- the huge mountain range formed when Africa pushes northward into
Europe in Eocene time
- the supercontinent that formed in the late Palaeozoic and broke
apart in Triassic time
- Where is the continental rise?
- at the top of the continental slope
- at the seaward edge of a deep ocean trench
- between the edge of the abyssal plain and the continental slope
- at the top of a mid-ocean ridge
- What term denotes the vast, deep, flat, sediment-covered parts of the
ocean basin? (Hint: They make up the majority of the ocean basins.)
- continental margins
- abyssal plains
- submarine canyons
- trenches
- Which best describes the boundary between northern India and Eurasia?
- two continental plates are converging
- two continental plates are diverging
- an oceanic plate is diverging from a continental plate
- two continental plates are sliding past each other along the
northern India transform fault
- Volcanic island arcs are associated with which plate boundary?
- convergent, passive trailing margins of two continental plates
- divergent, two oceanic plates
- transform, an oceanic plate and a continental plate
- convergent, two oceanic plates
- The concept that rocks of the crust and upper mantle are floating in
gravitational balance is known as:
- elastic rebound
- isotropy
- uniformitarianism
- isostasy
- Which one describes a normal fault?
- the hanging wall block below an inclined fault plane moves
downward relative to the other block
- the footwall block below an inclined fault plate moves downward
relative to the other block
- the hanging wall block above an inclined fault plane moves
downward relative to the other block
- the footwall block above an inclined fault plane moves upward
relative to the other block
- Which area and type of terrain result from active or recently-active
normal faulting?
- the Basin and Range, eastern USA
- the Valley and Ridge, western USA
- the Valley and Ridge, eastern USA
- the Basin and Range, western USA
- Which one is not a very long-lived radioactive isotope?
- 238U
- 40K
- 87Rb
- 14C
- What is an unconformity?
- a buried fault or fracture with older rocks above and younger
rocks below
- a buried surface of erosion separating younger strata above from
older strata below
- a buried fault or fracture with younger strata above and older
strata below
- the contact between a cross-cutting pluton and sedimentary rocks
- For nos 40-43, refer to
Figure 1. Match the
following lithospheric plates (indicated by a number) with the
corresponding letter choice.
- African Plate
- Nazca Plate
- Pacific Plate
- Eurasian Plate
- Antarctic Plate
- Of the original starting amount of radioactive parent isotope, 25%
remains and 75% has decayed. How many half-lives have passed?
- 0.5
- 1.5
- 2
- 3
- Which one is not a process of radioactive decay?
- electron capture
- alpha emission
- delta capture
- beta emission
- Which statement applies to an anticline?
- a fault in which strata dip away from the axis
- erosion exposes the oldest strata along the axial part of the
fold
- a bowl-shaped depression
- a fold in which the strata dip toward the axis
- According to geologists, the continental crust is best described
as:
- 10 km thick, granitic composition
- 20-60 km thick, basaltic composition
- 20-60 km thick, granitic composition
- 10 km thick, basaltic composition
- The most common detrital sedimentary rock is?
- sandstone
- slate
- siltstone
- shale
- Today, we are living in the _______ Era.
- Cenozoic
- Proterozoic
- Mesozoic
- Palaeozoic
- The most aboundant element in Earth's atmosphere is:
- argon
- carbon dioxide
- oxygen
- nitrogen
Figure 1. World Plate Map
David Sandwell
dsandwell@ucsd.edu
Greg Anderson
ganderson@ucsd.edu
Thu Mar 13 12:18:38 PST 1997