(1) What are seismic waves?
(2) What is the difference between S and P waves?
(a) What controls their velocity in the earth?
(b) Which travels faster, S or P waves.
(3) What is the difference between seismic reflection and seismic refraction
in the earth?
(a) How can each tell us something about the composition
and structure of te earth?
(b) How can we tell that the outer core is liquid?
(4) Why are multiple refelctors in reflection seismic surveys problematic and how can multiple reflectors be recognized?
(5) What is seismic tomography?
(6) What is a gravity anomaly map, and what causes the anomalies?
(7) When we consider isostasy, what do we mean we refer to the depth of compensation? If a mountain is in isostatic equillibrium, which gravity is larger; the free-air or Bouguer? Explain Why?
(8) What is the difference between Airy's and Pratt's approach towards attaining isostatic equilibrium?
(8) How would you tell the variation in latitude of a continent that has drifted in geologic time by using rock samples taken from lava flows of different ages?
(9) How is earth's magnetic field generated?
(a) How do rocks (igneoius rocks, sediments) preserve
the earth's magnetism?
(b) What is the Curie temperature?
(10) Why does the Earth have a magnetic field and the other terrestrial planets do not?
(11) Why does the ocean crust show magnetic stripes?
1) Mantle material at the core-mantle boundary has a density of A) 5.5 g/ cm to power of (3). B) 3.3 g/ cm to power of (3). C) 10 g/ cm to power of (3). D) aluminum. E) 13 g/ cm to power of (3). -Answer: __
2) Density of rock material within the Earth depends upon A) pressure. B) temperature. C) phase transitions. D) rock type. E) all of the above -Answer: __
3) Which aspect of a material's behavior is determined by measuring the change in volume resulting from applied stress? A) shear strain B) bulk modulus C) shear modulus D) compressional strain E) elasticity -Answer: __
4) A ratio of stress to strain is A) elastic modulus. B) strain multiple. C) volumetric strain. D) bulk modulus. E) shear strain. -Answer: __
5) The Earth zone with zero shear modulus is the A) upper mantle. B) outer core. C) lithosphere. D) inner core. E) lower mantle. -Answer: __
6) Seismic body waves are A) P waves only. B) S waves only. C) both P and S waves. D) surface waves. E) all of the above -Answer: __
7) The seismic waves which are most damaging to human structures are A) P waves. B) S waves. C) surface waves. D) body waves. E) Richter waves. -Answer: __
8) A(n) __________ is a slow transverse wave that travels through solids only and causes a shearing motion. A) surface wave B) S-wave C) L-wave D) P-wave E) T-wave. -Answer: __
9) The seismic waves used to locate the source and cause of a seismic disturbance are A) P waves. B) S waves. C) both P and S waves. D) surface waves. E) Rayleigh waves. -Answer: __
10) The velocity of seismic P waves varies most directly with A) elastic modulus and density. B) bulk modulus and rock type. C) strength of the disturbance. D) shear strength and density. E) rock elasticity. -Answer: __
11) Seismic waves most useful for analyzing whole Earth structure are A) direct waves. B) surface waves. C) reflected and refracted waves. D) reflected waves. E) direct and reflected waves. -Answer: __
12) P waves in the lower mantle near the boundary with the outer core travel at velocities of about A) 3 km/sec. B) 14 km/sec. C) the same as S waves. D) 5 m/sec. E) 14 m/sec. -Answer: __
13) Normal mode oscillation of the Earth provides direct information about A) elastic modulus. B) shear strain. C) wave velocity. D) density. E) all of the above -Answer: __
14) The key property of seismic waves which helps us determine crustal thickness is A) velocity variation. B) angle of reflection. C) angle of refraction. D) surface wave amplitude. E) S wave damping. -Answer: __
Match the crustal thickness (A through D) with the specific crustal units below.
15) Average for oceanic crust A) 70 km B) 7 km C) 24 km D) 30 km -Answer: __
16) Average for continental crust A) 70 km B) 7 km C) 24 km D) 30 km -Answer: __
17) Maximum for oceanic crust A) 70 km B) 7 km C) 24 km D) 30 km -Answer: __
18) Maximum for continental crust A) 70 km B) 7 km C) 24 km D) 30 km -Answer: __
19) The Mohorovicic discontinuity, or Moho, is the boundary between __________ and __________. A) mantle; core B) crust; mantle C) crust; low velocity zone D) outer core; inner core E) all of the above -Answer: __
20) The low velocity zone A) may be partly melted. B) is the asthenosphere. C) is elusive under ancient continents. D) directly underlies the lithosphere. E) all of the above -Answer: __
21) Evidence for a liquid outer core is A) the asthenosphere. B) the Earth's heat flow. C) the P-wave shadow zone. D) the Z-wave shadow zone. E) none of the above -Answer: __
22) Evidence for a liquid outer core is A) the asthenosphere. B) the Earth's heat flow. C) the S-wave shadow zone. D) the X-ray zone. E) none of the above -Answer: __
23) High velocity anomalies have been detected by seismic tomography at A) magma chambers. B) spreading ridges. C) continental rifts. D) the asthenosphere. E) subduction zones. -Answer: __
24) From among the following seismic velocities measured in the same layer of rocks, which is most likely to be that of a P-wave? A) 4.5 km/sec B) 3.0 km/sec C) 6.5 km/sec D) 4.0 km/sec E) none of the above -Answer: __
25) P-waves A) can travel through solid. B) can travel through liquid. C) can be characterized by compressional waves. D) may refract in the liquid outer core. E) all of the above -Answer: __
26) Seismic reflection results from A) seismic waves bending when they cross a boundary. B) b. seismic waves bouncing when they cross a boundary. C) refraction of seismic waves. D) the P-wave shadow zone. E) regional differences in Earth's magnetic field. -Answer: __
27) Seismic waves that pass through the interior of the Earth are called A) surface waves. B) tsunamis. C) radio waves. D) body waves. E) permanent waves. -Answer: __
28) Seismology is A) the study of earthquakes. B) the study of plate tectonics. C) not concerned with geophysics of the Earth. D) not a branch of geology. E) the study of igneous rocks. -Answer: __
29) Where would you weigh the most? A) at the North Pole B) at the equator C) on the Moon D) on Mars E) atop Mt. Everest -Answer: __
30) What is the gravitational force in Newtons on a person who weighs 90 kg? A) 88.2 kgm/ sec to power of (2) B) 88.2 m/ sec to power of (2) C) 882 kgm/ sec to power of (2) D) 1.9 kgm/ sec to power of (2) E) 8.82 kg/ sec to power of (2) -Answer: __
31) A gal is A) 1 cm/ sec to power of (2). B) named after Galileo. C) one millionth of a g. D) 0.01 m/ sec to power of (2). E) all of the above -Answer: __
32) A milligal (mgal) is equivalent to A) one million gals. B) one thousand gals. C) one-thousandth gal. D) one-millionth gal. E) none of the above -Answer: __
33) The gravity measurement correction for Earth's oblate spheroid shape is A) latitude. B) elevation. C) Bouguer. D) free-air. E) none of these -Answer: __
34) The large Bouguer anomaly low for North America is associated with this geologic feature. A) the Sierra Nevada B) the Appalachians C) Hawaii D) the Colorado Plateau E) the San Andreas Fault -Answer: __
35) A large mass of high mountain ranges is supported by A) thin continental crust. B) lateral squeezing. C) dense upper mantle. D) mantle plumes. E) a crustal root. -Answer: __
36) The mass of a small, isolated hill is supported by A) continental crust. B) lateral squeezing. C) dense upper mantle. D) mantle plumes. E) a crustal root. -Answer: __
37) The angular difference between the magnetic and geographic north poles is called A) bar magnet theory. B) Curie pint. C) magnetic declination. D) axial tilt. E) inclination. -Answer: __ 3
8) Which factor is thought to have "kick started" Earth's self-exciting dynamo? A) liquid iron B) radioactive decay C) the Sun's magnetic field D) hear from inner core E) outer core circulation -Answer: __
39) Rock magnetism orientation in a lava becomes 'locked in' A) at the Curie temperature. B) when the lava erupts. C) at the blocking temperature. D) after crystallization. E) in the magma chamber. -Answer: __
40) When the magnetic field of Earth is reversed, A) Earth flips over in its orbit. B) the sense of rotation of the Earth is also reversed. C) all existing rocks on and in Earth change their magnetic polarity. D) the moon spins faster than normal. E) Earth's magnetic poles switch places. -Answer: __
41) Earth's magnetic field is similar to that of a bar magnet because A) it has a monopole. B) the field is one long pole. C) the field is dipolar. D) the bar magnet is a dynamic magnet. E) the inner core of Earth is shaped like a north-south trending bar. -Answer: __
Solar system bodies exhibit several different situations with regard to their magnetic fields. Match the body (A through E) to its currently known status in the questions below.
42) This body has an active magnetic field from circulating molten iron A) Uranus B) Venus C) Earth D) Sun E) Moon -Answer: __
43) Its slow backward spin probably prevents development of a dipolar magnetic field A) Uranus B) Venus C) Earth D) Sun E) Moon -Answer: __
44) This body had a magnetic field about 3 Ga, before its core froze solid A) Uranus B) Venus C) Earth D) Sun E) Moon -Answer: __
45) This body has the strongest magnetic field in the solar system A) Uranus B) Venus C) Earth D) Sun E) Moon -Answer: __
46) This body has an off-center magnetic field that may originate in its outer layers A) Uranus B) Venus C) Earth D) Sun E) Moon -Answer: __
47) Most of our knowledge of the deep interior of the Earth comes from A) information derived from deep oil wells. B) density measurements. C) deep mines. D) behavior of seismic waves passing through the Earth. E) meteorites. -Answer: __ 48) The properties of seismic waves and the characteristics of their passage through Earth are evidence that A) the lithosphere is rigid. B) the Earth is an inhomogeneous mass. C) the outer core is liquid. D) the mantle is the thickest zone. E) all of the above -Answer: __