Previous Exam [5]
After melting of a continental ice cap, the surface of the continent will tend to ______. A) rise B) sink C) rise or sink depending on the thickness of the ice cap D) remain the same
A
Calculations suggest that the inner core __________. A) spins at a faster rate than the rest of the Earth B) spins in the opposite direction of the rest of the Earth C) spins at the same rate as the Earth D) does not spin at all
A
Continental crust is ________ oceanic crust. A) less dense than B) the same density as C) more dense than D) Geoscientists have no idea.
A
Earthquakes that originate at depths greater than 100 km are associated with ______ plate boundaries. A) convergent B) transform C) divergent D) convergent, divergent, and transform
A
Fault mechanisms at subduction zones are called ___________. A) megathrusts B) reverse thrusts C) compressional faults D) megafaults
A
How thick is the oceanic crust? A) approximately 7 km B) approximately 70 km C) approximately 35 km D) approximately 240 km
A
If erosion stripped the top off a dome, one would find __________. A) the oldest rocks exposed in the center B) the youngest rocks exposed in the center C) a linear pattern of rock outcrops D) A and C
A
Ninety percent of the Earth is made up of which four elements? A) iron, oxygen, silicon, and magnesium B) oxygen, nitrogen, hydrogen, and silicon C) magnesium, aluminum, silicon, and oxygen D) silicon, calcium, aluminum, and iron
A
Rocks that undergo elastic deformation will _____________. A) return to their original shape once the stress is released B) cause a large magnitude earthquake C) undergo permanent deformation D) none of the above
A
The Earth's core is made up primarily of ________. A) iron B) lead C) oxygen D) silicon
A
The dip of a unit represents the ___________. A) angle at which the bed inclines from the horizontal B) direction of intersection of the rock layer and a horizontal surface C) part of the unit that has been eroded D) tilt of the rock unit before deformation
A
The modified Mercalli intensity scale measures ____________. A) the amount of destruction caused by an earthquake B) the amount of slip on a fault plane caused by an earthquake C) the amplitude of the surface waves D) all of the above
A
The modified Mercalli intensity scale measures ____________. A) the amount of destruction caused by an earthquake B) the amount of slip on a fault plane caused by an earthquake C) the amplitude of the surface waves D) all of the above
A
What drives plate tectonics? A) mantle convection B) magnetic reversals C) volcanism D) solar energy
A
What is metasomatism? A) a change in the bulk composition of a rock during metamorphism due to hydrothermal fluids B) metamorphism caused by nearby magmatic intrusions C) metamorphism caused by tectonic movements along faults D) the parallel alignment of minerals in a metamorphic rock
A
Which of the following properties increases in the direction of the arrows in the diagram below? Felsic=>Intermediate=>Mafic A) melting temperature B) potassium content C) silica content D) viscosity
A
Which of the following types of waves is a compressional wave? A) P waves B) S waves C) surface waves D) all of the above
A
In a deep mine, temperatures increase at the rate of ______. A) approximately 2.5°C per kilometer B) approximately 25°C per kilometer C) approximately 250°C per kilometer D) approximately 2500°C per kilometer
B
In a deep mine, temperatures increase at the rate of ______. A) approximately 2.5°C per kilometer B) approximately 25°C per kilometer C) approximately 250°C per kilometer D) approximately 2500°C per kilometer
B
Large crystals surrounded by much smaller crystals in an igneous rock is called a _______. A) pyroclast 8) porphry or porphyritic C) pyroxene D) pumice E) phenocryst
B
The Earth's magnetic field shields the surface of the Earth from _________. A) asteroids B) solar winds C) intergalactic radio waves D) all of the above
B
The Earth's major layers include (from outermost to innermost) . A) inner core, outer core, mantle, crust B) crust. mantle, outer core. inner core C) crust, outer core, inner core, mantle D) outer core, inner core, mantle, crust
B
The largest jump in density within the Earth is at the _______. A) crust-mantle boundary B) mantle-core boundary C) upper mantle-lower mantle boundary D) outer core-inner core boundary
B
The oceanic crust consists mostly of ______. A) felsic rocks B) mafic rocks C) sedimentary rocks D) ultramafic rocks
B
This mafic silicate mineral consists of silicon oxygen tetrahedra bonded in a double chained configuration A) Biotite Mica B) Amphibole C) Quartz D) Feldspar E) Olivine F) Pyroxene
B
Variations in the pull of gravity at the surface of the Earth are linked to ________ A) variations in lithospheric densities B) variations in the mantle temperature C) variations in latitude D) variations in the liquid outer core
B
What causes the sharp increases in the velocity of S waves at 400 and 660 kilometers depth in the mantle? A) changes in the composition of the mantle B) changes in the mineral structures C) changes in the pressure of the mantle D) changes in the temperature of the mantle
B
What principle is based on the continents being less dense than the underlying mantle? A) epeirogeny B) isostasy C) superposition D) tomography
B
What type of seismic wave causes the most building damage? A) P waves B) surface waves C) S waves D) They all cause building damage.
B
What type of seismic wave causes the most building damage? A) P waves B) surface waves C) S waves D) They all cause building damage.
B
What type of seismic waves are S waves? A) compressional waves B) shear waves C) surface waves D) tsunamis
B
What type of seismic waves are S waves? A) compressional waves B) shear waves C) surface waves D) tsunamis
B
When tensional forces act on a fault plane, they produce _________. A) reverse faults B) normal faults C) strike slip faults D) all of the above
B
Which of the following correctly lists the order in which seismic waves arrive at a seismograph station? A) P waves → surface waves → S waves B) P waves → S waves → surface waves C) S waves → P waves → surface waves D) surface waves → P waves → S waves
B
Which of the following marks the boundary between the crust and the mantle? A) a decrease in P-wave velocity and a change in rock type B) an increase in P-wave velocity and a change in rock type C) a decrease in P-wave velocity, but no change in rock type D) an increase in P-wave velocity, but no change in rock type
B
Which of the following marks the boundary between the crust and the mantle? A) a decrease in P-wave velocity and a change in rock type B) an increase in P-wave velocity and a change in rock type C) a decrease in P-wave velocity, but no change in rock type D) an increase in P-wave velocity, but no change in rock type
B
Which of the following processes is responsible for the recording of the magnetic reversals on the seafloor? A) tectonosilicate magnetism B) thennoremanent magnetism C) metamorphic magnetism D) depositional remnant magnetism
B
Which of the following regions in the Earth consists primarily of olivine and pyroxene? A) the crust B) the upper mantle C) the lower mantle D) the inner core
B
Why is the average elevation of the continents higher than the average elevation of the seafloor? A) because melting of large ice caps has caused isostatic rebound of the continents B) because oceanic crust is composed of denser rocks than the continental crust C) because the continents are supported by upwelling mantle currents D) because subduction pulls down the seafloor
B
A fault plane strikes north-south and dips steeply to the west. Geologic observations indicate that most of the fault movement was dip-slip and that the younger rocks occur east of the fault and older rocks occur west of the fault. What type of fault is this? A) a left-lateral fault B) a normal fault C) a reverse fault D) a right-lateral fault
C
A fold that has a non-horizontal fold axis is called a(n) ________ fold. This is typically represented by a U or slightly V- shaped exposure of the rock layers as viewed from the surface. A) symmetrical B) asymmetrical C) plunging D) overturned
C
A geothermometer is ___________. A) a device that measures current rock temperatures B) a device that measures temperature when lowered into deep drill holes C) a mineral assemblage that reveals the maximum temperature attained by a rock D) the range of temperatures encountered by a rock in its geologic history
C
Based on seismic tomographic images, how deep do subducting slabs extend? A) to the crust-mantle boundary B) to the upper mantle-lower mantle boundary C) to the core-mantle boundary D) to the inner core-outer core boundary
C
Find the correct volcano/volcanic product match. A) shield volcano/andesite B) domelbasah C) fissure/basalt D) shield volcano/rhyolite
C
How fast do tsunamis travel across the ocean? A) up to 5 kilometers per hour B) up to 60 kilometers per hour C) up to 800 kilometers per hour D) up to 10,000 kilometers per hour
C
How fast do tsunamis travel across the ocean? A) up to 5 kilometers per hour B) up to 60 kilometers per hour C) up to 800 kilometers per hour D) up to 10,000 kilometers per hour
C
How many seismograph stations are needed to locate the epicenter of an earthquake? A) one B) two C) three D) four
C
How many seismograph stations are needed to located the epicenter of an earthquake? A) four B) one C) three D) two
C
On average, the Earth's lithosphere is approximately ____ km thick. A) 4 B) 20 C) 100 D) 500
C
Seismic wave speeds increase with __________. A) decreasing density and temperature B) decreasing density and increasing temperature C) increasing density and decreasing temperature D) increasing density and temperature
C
Seismic waves that bounce off a boundary between two different materials are said to be ________, whereas seismic waves that cross the boundary and are bent are said to be ________. A) refracted, reflected B) reflected, transmitted C) reflected, refracted D) refracted, transmitted
C
The S-wave shadow zone extends from ____ to 180° angular distance from the earthquake focus. A) 45° B) 75° C) 105° D) 145°
C
The ground motion during a Richter magnitude 8 earthquake is ______ times greater than the ground motion during a Richter magnitude 6 earthquake. A) 2 B) 10 C) 100 D) 1000
C
The modified Mercalli intensity scale measures ______. A) the amount of slip on a fault plane caused by an earthquake B) the amplitude of the surface waves C) the amount of destruction caused by an earthquake D) all of the above
C
The moment magnitude of an earthquake is proportional to ________ A) the area of the fault break B) the seismic energy released during the rupture C) both A and B D) neither A nor B
C
The moment magnitude of an earthquake is proportional to_____________. A) the area of the fault break B) the seismic energy released during the rupture C) both A and B D) neither A nor B
C
The moment magnitude of an earthquake is proportional to_____________. A) the area of the fault break B) the seismic energy released during the rupture C) both A and B D) neither A nor B
C
What are the plates of plate tectonics made up of? A) asthenosphere B) crust C) lithosphere D) mantle
C
What sort of fault type is likely to form where shear forces combine with compressive or tensional forces? A) a normal fault B) a thrust fault C) an oblique-slip fault D) a strike-slip fault
C
Where do P waves travel fastest? A) in the upper mantle B) in the outer core C) in the lower mantle D) in the inner core
C
Which layer in the Earth does not transmit S waves? A) the crust B) the inner core C) the mantle D) the outer core
C
Which of the following Earth systems powers the Earth's magnetic field? A) the climate system B) the plate tectonic system C) the geodynamo system D) all of the above
C
Which of the following correctly lists the three rock types in order of increasing P-wave velocity? A) gabbro → granite → peridotite B) granite → peridotite → gabbro C) granite → gabbro → peridotite D) peridotite → gabbro → granite
C
Which of the following makes up most of the Earth by volume? A) crust B) inner core C) mantle D) outer core
C
Which of the following measurements collected from seismograph stations gives scientists information regarding the type of faulting that occurred during an earthquake? A) the amount of slip B) the amplitude of the ground shaking C) the first motion of the P waves D) the time interval between the arrival of the P and S waves
C
Which of the following pairs of intrusive and extrusive rocks have the same chemical composition? A) granite and andesite B) diorite and rhyolite C) gabbro and basalt D) gabbro and rhyolite
C
Which of the following processes would most likely yield a granitic magma? A) partial melting of the core B) partial melting of subducted oceanic crust and sediments C) partial melting of the continental crust D) partial melting of the upper mantle
C
Which of the following types of seismic waves are the slowest? A) P waves B) S waves C) surface waves D) P waves, S waves, and surface waves all travel at the same speed.
C
Geologic maps are used to depict ________. A) the strike and dip of the rock units at the Earth's surface B) the rock formations exposed on the Earth's surface C) the orientation of geologic structures that deform rocks exposed at the Earth's surface D) all of the above
D
If the position between OPS antennas on two plates moving away from each other changes by S mm/yr, then each plate is moving at approximately A) 1 mm/yr B) 5 mm/yr C) 10 mm/yr D) 2.5 mm/yr
D
Magma generated in the Earth's interior rises because it is _______ than the surrounding rocks. A) more volatile B) lower in viscosity C) denser D) less dense
D
Shallow earthquakes, less than 20 km deep, are associated with ___________. A) convergent plate boundaries B) transform plate boundaries C) divergent plate boundaries D) all of the above
D
The area on the surface of the Earth where P waves and S waves are not recorded by seimograms following an earthquake event are referred to as _______. A) reflection zones B) aseismic areas C) geoid highs D) shadow zones
D
The asthenosphere is ____________. A) cool and strong B) cool and weak C) hot and strong D) hot and weak
D
The average time between large earthquake events along a fault is known as the ______ interval. A) seismic B) hazard C) fault slip D) recurrence
D
The chemical formula {Mg.Fe)2Si04 describes which of the following minerals? A) pyroxene B) mica C) feldspar D) olivine
D
The energy released during a magnitude 8 earthquake is approximately ______ times larger than the energy released during a magnitude 6 earthquake. A) 2 B) 10 C) 100 D) 1000
D
The energy released during a magnitude 8 earthquake is approximately ______ times larger than the energy released during a magnitude 6 earthquake. A) 2 B) 10 C) 100 D) 1000
D
The volcanism at spreading centers occurs as a result of melting. A) convection B) conduction C) fluid-induced D decompression
D
What determines whether a rock deforms in a brittle fashion versus a ductile fashion? A) temperature B) rock type C) rate of deformation D) all of the above
D
What drives plate tectonics? A) erosion B) solar energy C) thermal conduction D) thermal convection
D
What type of mineral is calcite? A) sulfates B) oxides C) sulfide D) carbonates E) silicates
D
Which layer in the Earth does not transmit S waves? A) the crust B) the inner core C) the mantle D) the outer core
D
Which of the following locations is least likely to have active volcanoes? A) island arc B) continental rift valley C) mid-ocean ridge D) transform fault
D
Which of the following processes is responsible for the recording of the magnetic reversals on the seafloor? A) depositional remanent magnetism B) tectonosilicate magnetism C) metamorphic magnetism D) thermoremanent magnetism
D
Which of the following relationships is correct? A) asthenosphere = crust B) lithosphere = crust C) asthenosphere = crust + upper mantle D) lithosphere = crust + upper mantle
D
Which of the following seismic waves will arrive at a seismograph first? A) P B) S C) PP D) SS
D
Which of the following types of tectonic forces causes faulting? A) compressive forces B) shear forces C) tensional forces D) all of the above
D
How fast do tsunamis travel across the ocean? A) up to 10,000 kilometers per hour B) up to 800 kilometers per hour C) up to 60 kilometers per hour D) up to S kilometers per hour
B
If a magma undergoes fractional crystallization, the remaining magma will be A) exactly the same 8) more felsic C) more mafic D) less viscous
B
An earthquake's Richter magnitude is based on ______. A) the amount of energy released during an earthquake B) the amount of ground movement caused by seismic waves C) the distance between the earthquake and the seismograph station D) the observed effects on people and structures
B
An overturned fold is characterized by two limbs _________. A) at right angles to one another B) dipping in the same direction, with one limb tilted beyond vertical C) dipping steeply in opposite directions D) dipping gently in opposite directions
B
As the distance to an earthquake increases, __________. A) the elapsed time before the P waves arrive decreases B) the elapsed time before the S waves arrive increases C) the amount of ground shaking increases D) the time between the arrival of the P and S waves decreases
B
Evidence for the internal structure of the Earth is mostly based on __________. A) heat flow measurements B) waves generated by earthquakes C) existence of a magnetic field D) deep mines and drilling
B
How do rock particles move during the passage of an S wave through the rock? A) back and forth parallel to the direction of wave travel B) back and forth at right angles to the direction of wave travel C) in a rolling circular motion D) in a rolling elliptical motion
B
A seismic observatory typically has instruments that measure ______ motion(s). A) up-down B) horizontal north-south C) horizontal east-west D) all of the above
D
Energy waves that are released during an earthquake are called __________. A) shock waves B) elastic waves C) stress waves D) seismic waves
D
