Introduction to Seismology Quiz 2

Question 1 What is the approximate distance from the surface to the center of Earth?  700 km   2,900 km   6,400 km   24,000 km   Question 2 How fast do P waves travel through granite?  4 kilometers per second   6 kilometers per second   8 kilometers per second   12 kilometers per second   Question 3 Which of the following statements istrue?  Liquids do not transmit P waves.   P-wave velocities are greater in the core than in the mantle.   Seismic waves follow straight paths through the interior of Earth.   The S-wave shadow zone is larger than the P-wave shadow zone.   Question 4 Which of the following seismic waves will arrive at a seismograph first?  P   S   PP   SS   Question 5 Which layer in Earth doesnottransmit S waves?  the crust   the inner core   the mantle   the outer core   Question 6 Where do P waves travel fastest?  in the upper mantle   in the outer core   in the lower mantle   in the inner core   IncorrectQuestion 7 Continental crust beneath mountains can be up to ___ kilometers thick.  10   40   70   100   Question 8 How thick is the oceanic crust?  approximately 7 km   approximately 70 km   approximately 35 km   approximately 240 km   Question 9 The oceanic crust consists mostly of  felsic rocks   mafic rocks   sedimentary rocks   ultramafic rocks   Question 10 Which of the following statements about the Mohorovičić discontinuity (Moho) isfalse?  The Moho marks the top of a partially molten layer.   The Moho separates denser rocks below from less dense rocks above.   The Moho separates the crust from the mantle.   The speed of seismic waves increases as they pass down through the Moho.   Question 11 Which of the following statements isfalse?  P waves travel slower in the crust than in the mantle.   The crust is denser than the mantle.   The crust-mantle boundary is called the Mohorovičić discontinuity.   The oceanic crust consists of basalt and gabbro.   Question 12 Which of the following marks the boundary between the crust and the mantle?  a decrease in P-wave velocity and a change in rock type   an increase in P-wave velocity and a change in rock type   a decrease in P-wave velocity, but no change in rock type   an increase in P-wave velocity, but no change in rock type   Question 13 Which of the following regions in Earth consists primarily of olivine and pyroxene?  the crust   the upper mantle   the lower mantle   the inner core   Question 14 How thick is average lithosphere?  25 km   100 km   250 km   1000 km   Question 15 Which of the following statements about the asthenosphere isfalse?  The asthenosphere lies beneath the lithosphere   The asthenosphere is stronger than the lithosphere   The asthenosphere rises close to the surface beneath mid-ocean ridges   The asthenosphere is partially molten   Question 16 The boundary between the mantle and the core lies at a depth of approximately  300 kilometers   1,000 kilometers   3,000 kilometers   10,000 kilometers   Question 17 At what depth does the transition from the upper mantle to the lower mantle occur?  approximately 400 to 600 kilometers   approximately 2000 to 3000 kilometers   approximately 700 to 900 kilometers   approximately 3000 to 5000 kilometers   Question 18 What element makes up most of Earth's core?  iron   oxygen   magnesium   silicon   Question 19 Which of the following statements about Earth's core istrue?  The inner core and the outer core are both liquid   The inner core and the outer core are both solid   The inner core is liquid and the outer core is solid   The inner core is solid and the outer core is liquid   Question 20 Seismic wave speeds increase with  decreasing density and temperature   decreasing density and increasing temperature   increasing density and decreasing temperature   increasing density and temperature   Question 21 Seismic tomography has revealed that seismic waves in the uppermost mantle are relatively  fast beneath both mid-ocean ridges and subduction zones   fast beneath mid-ocean ridges and slow beneath subduction zones   slow beneath mid-ocean ridges and fast beneath subduction zones   slow beneath both mid-ocean ridges and subduction zones   Question 22 Where is Earth's magnetic field generated?  in the crust   in the mantle   in the outer core   in the inner core   Question 23 Approximately how often does Earth's magnetic field reverse itself?  every 50 years   every 5,000 years   every 500,000 years   every 50,000,000 years   Question 24 Which of the following Earth systems powers Earth's magnetic field?  the climate system   the plate tectonic system   the geodynamo system   all of the above   Question 25 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 ________.  refracted; reflected   reflected; transmitted   reflected; refracted   refracted; transmitted   Question 26 Which of the following statements isfalse?  S waves slow down as they travel through the mantle   P waves slow down in the outer core   S waves cannot transmit through the outer core   P waves travel through the inner core   Question 27 The area on the surface of Earth where P waves and S waves are not recorded by seimograms following an earthquake event are referred to as  reflection zones   aseismic areas   geoid highs   shadow zones   Question 28 The graphical curve that describes how temperature changes with depth in Earth is called the  tempotherm   heating gradient   geoid gradient   geotherm   Question 29 Earth's magnetic field shields the surface of Earth from  asteroids   solar winds   intergalactic radio waves   geotherms   Question 30 Earth's inner core was discovered by seismologist  Beno Gutenberg   Andrija Mohorovičić   Hugo Benioff   Inge Lehmann   Question 31 In a deep mine, temperatures increase at the rate of approximately ______ per kilometer.  2.5°C   25°C   250°C   2,500°C 