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Practice Exams |
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| Spring 2000 ( 42514R MW 3:30-4:50 pm, SLH 200) | |
| Professor Leon Teng | Office: SCI 101, 740-5838 |
| e-mail: lteng@terra.usc.edu
www.usc.edu/dept/LAS/factech/teng |
Office Hours: 1:00-3:00 pm, MW
and by appointment |
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Geology 240 Earthquakes
1997 Spring Midterm #1 February 13, 1997 Teng
Note: 1. One point each entry on your answer sheets unless
otherwise specified.
2. Answer Sections C, D, and E on the scantron. Answer sections
A and B on the
Second Answer Sheet (pages 7 and 8).
A. QUESTIONS (3 point each question in lower case alphabet):
1. Given seismograms (Figure A). Answer each question with
no more than ONE sentence:
a. What are the NS, Vert. and EW, why is it necessary to have
all three of them?
b. If the time scale given is within the minute frame of 11:45,
beginning at 28th second, what
are the P-wave and S-wave arrival times approximately?
c. Is this the record of a nearby earthquake or a far away earthquake?
d. Approximately how far away is the epicenter from the recording
station?
2. Given seismograms (Figure B). Answer each question with no
more than ONE sentence:
a. Is this the record of a nearby earthquake or a far away earthquake?
b. What is Up-down, NS, and EW, why are they necessary?
c. What is the "minute mark" ?
d. Why are surface waves larger in amplitude than body waves
at large distance?
e. Why this figure composed of 12 traces instead of one trace?
3. For seismic belts, why the width of the mid-ocean seismic
belt is narrow as compared with the broad arcuate Circum-Pacific
seismic belts?
4. Why is tsunami not too much a threat of southern California?
5. About hot spots:
a. What is the cause of the Hawaii island chain and the Emperor
seamount chain?
b. Why they do not form a straight line?
6. Give an example that the property of matters depends on both
temperature and pressure.
7. What is the Currie temperature?
8. About radiometric dating:
a. What is a radiometric clock?
b. When is a radiometric clock start ticking?
c. What does it mean by half-life of a radioactive element?
9. About fault-plane solution:
a. Which part of the seismogram gives the input data for the
fault-plane solution?
b. What is a focal sphere?
c. Why we need to use a stereographic projection to do the fault-plane
solution?
10. About southern California:
a. What is the orientation of the maximum principal stress s1
in the southern California?
b. What type of faulting has produced the 1994 Northridge earthquake?
c. What type of fault is the Newport-Inglewood fault?
11. Give an example of the confining pressure?
B. FILL-IN BLANKS
12. Answer the following 4 questions based on the seismic
records shown in Figure B, the wiggle lines are called _______________(1).
These records are written for a big event due WEST of the seismic
station.
Phase a is the __________________(2) wave.
Phase b is the __________________(3) wave.
Phase c is the __________________(4) wave.
Phase d is the __________________(5) wave.
In Figure A, is the first P wave motion compressional or dilatational?
______(6).
13. If a big subduction earthquake occurs in Chile, the induced
tsunami will take _________(time) to reach Japan shores.
14. The oceanic crust consists of a ____________(1) layer of
about ______(2) km
thick. The continental crust consists of two layers: the top
__________(3)
layer and the bottom ______________(4) layer with a collective
thickness of
about _______(5) km. Under the Himalayas, the continental crust
can be as
thick as ________(6) km which is a consequence of the _____________(7)
between the Indian continent with the Eurasian continent.
15. By far, the most common type of earthquake is ____________
earthquake.
16. The ____________ theory explains the process of tectonic
stress accumulation and then eventually leads to the rupture
of the rock formation --- an earthquake.
17. The Emperor seamount chain and the Hawaiian Archipelago are
formed due to the existence of a _____________________(1) in
the mantle. The different orientations between the Emperor seamount
chain and the Hawaiian Archipelago reflect the __________________(2)
direction on the movement of the Pacific plate in the past.
18. The oceanic crust is created at ____________________________(1)
and
"consumed" or "destroyed" at _________________________(2).
19. The three major types of plate boundary are:
(a)______________________________
(b)______________________________
(c)______________________________
Geographical examples of (a), (b), (c) are, respectively:
(d)______________________________
(e)______________________________
(f)______________________________
20. Within the earth's interior travel body waves that consist
of _____________(1)
and ________________(2). At the earth's surface travel surface
waves that consist of _____________________________(3) and _____________________(4).
These four waves are characterized by the nature of their particle
motions.
(a) As _______________(5) waves pass by, a particle oscillates
in a direction ______________________________(6) the wavefront.
(b) As _______________(7) waves pass by, a particle oscillates
in a direction ______________________________(8) the wavefront.
(c) As _______________(9) waves pass by, a surface particle does
_________(10)
___________________ motion.
(d) As _______________(11) waves pass by, a particle oscillates
___________(12) the earth's surface and _________________________(13)
the direction of wave propagation. Of all four waves, the (14)______________
wave has fastest velocity so it arrives first.
C. TRUE OR FALSE
21. Depending on the pressure and temperature, materials such
as water can assume 3 phases: as a solid, as a liquid, and as
a gas.
22. Scientists recently has successfully compressed hydrogen
into a metal.
23. The continental crust is about 30 km thick, while the oceanic
crust can be as thin as 5 km.
24. Lithosphere is the solid rocky part that forms the outer
75 to 100 km part of the earth.
25. Asthenosphere is the part of upper mantle that is very rigid.
26. The spreading ocean floor can be considered as a piece of
recording magnetic tape that records the earth's magnetic polar
reversals.
27. Lithosphere is created at the subduction zone and consumed
at the Benioff zones.
28. You often find sag pond and fault gouge in the fault zone.
29. Presently the Pacific plate is plunging under Washington
state that can potentially cause large subduction earthquake.
30. A fault plane's orientation is described by its strike and
dip.
31. Rocks will flow under high temperature and high pressure.
32. Following India, the islands of Indonesia was the next to
break up with Africa.
33. Magnetic stripes on the sea floor are generally perpendicular
to transform faults.
34. The magma from mid ocean ridges ( or the MOR) is highly viscous
because of high content of SiO2.
35. SiO2 is also the material that gives your watch accurate
time.
36. There are a lot of active explosive volcanoes on the west
coast of North America.
37. Earthquake's source is always a point called focus from which
all radiated seismic energy comes.
38. Fault-plane solution can uniquely determine (i.e., without
ambiguity) the dip and strike of the very rupture plane that
causes the earthquake.
39. If a fat pig is 400 lb., he put all his weight equally on
his four legs with hoofs measured two inches by two inches. The
normal stress he puts on the ground is 30 psi exactly, same as
the air pressure of your tires.
40. 50 million years later, one expects the NE portion of the
North Africa to become separated from the continent.
41. A rock slide from the mountain in Wrightwood in 1940 dumped
dark-colored rock debris of Catalina schist into the Mojave desert.
They can be seen as a 30-mile long inverted black triangle form
the airphoto.
42. Having surveyed the distribution of fossils, scientists found
close species affinities prevailed between Africa and South America.
43. Having surveyed the distribution of fossils, scientists found
close species affinities prevailed between Madagascar and India.
D. Multiple Choices
46. The Himalayas give a good example of
(a)convergent boundary, (b) divergent boundary, (c) transform
boundary.
47. Relative plate movement such as that between the North American
and the Pacific plates, occur at a rate of about
(a) a few millimeters per year, (b) a few centimeters per year,
(c) a few meters per year, (d) about 1 km per year.
48. The San Andreas fault show predominantly
(a) right lateral strike-slip, (b) left lateral strike-slip,
(c) normal dip slip, (d) reverse dip slip.
49. At which of the following locations one would expect to find
deep-focus earthquakes?
(a) California, (b) Iceland, (c) Japan, (d) Mid-Atlantic Ridge.
50. Transform faults on the sea floor offset
(a) ridges, (b) magnetic stripes, (c) both (a) and (b), (d) none
of the above.
51. Evidence for sea floor spreading includes the existence of
(a) mid oceanic ridges and deep focus earthquakes, (b) transform
faults and symmetrical magnetic anomalies, (c) a, b above, (d)
none above.
52. Among the many earthquakes in California, the three "monster"
earthquakes (largest ones) during recorded history are
(a) 1857-southern San Andreas, 1906-San Francisco, 1872 Owens
Valley,
(b) 1857-Owens Valley, 1906-southern San Andreas, and 1872-San
Francisco,
(c) 1906-San Francisco, 1872-southern San Andreas, and 1857-Owens
Valley.
53. The supercontinent, Pangaea, is thought to have broken
up about
(a) 2 million years ago, (b) 20 million years ago, (c) 200 million
years ago,
(d) 2 billion years ago.
54. For an earthquake, the orientation of the fault plane and
direction of slip can be determined from
(a) P-S travel times at many seismic stations around the earth,
(b) the first motion of the P-wave at many stations around the
epicenter, (c) the damage patterns, and (d) all the above.
55. Assuming the San Andreas fault moves two inches per year,
U.S.C. will become Stanford's football cross-town rival in about
(assume that Stanford is about 400 miles from USC at the present,
and one mile = 5280 feet)
(a) 2.5 million years, (b) 25 million years, (c) 250 million
years, (d) 13 million years.
56. One important fault that effects LA is the
(a) Garlock fault, (b) Newport Inglewood fault, (c) Owens Valley
fault,
(d) Pomona fault.
57. Another important fault that effects LA is
(a) Santa Monica fault, (b) Downtown fault, (c) Olympic fault,
(d) Pasadena fault.
58. The single most important earthquake belt is called the ____
belt.
(a) MOR, (b) Circum Pacific, (c) Mid-Atlantic, (d) San Andreas.
59. Which of the following would you least expect to find along
a convergent plate boundary?
(a) thrust fault, (b) fold mountain belt, (c) deep focus earthquake,
(d) rift zones.
60. The speed of tsunami can reach
(a) 4.5 MPH, (b) 45 MPH, (c) 450 MPH, (d) 4500 MPH.
61. Which of the following is an example of a seismic body wave?
(a) L, (b) Love, (c) S, (d) Rayleigh
62. The wavelength of tsunami can be as long as
(a) 2.4 km, (b) 24 km, (c) 240 km, (d) 2400 km.
63. The period of tsunami is in the neighborhood of
(a) 2 hours, (b) 20 minutes, (c) 2 minutes, (d) 2 seconds.
64. The brittle outer layer of the earth which is broken into
more than a dozen plates is called the
(a) crust, (b) lithosphere, (c) asthenosphere, (d) mantle.
65. Seamounts (a) are submerged flat-top volcanoes, (b) were
once above the sea surface, (c) both (a) and (b), (d) none of
above.
66. The seismic wave which will not travel through the liquid
outer core is the
(a) P wave, (b) S wave, (c) inner core wave, (d) none of the
above.
67. Tsunami is the name of
(a) an earthquake-causing big catfish in the Japanese folklore,
(b) tidal waves,
(c) seismic sea waves, (d) body waves.
68. The reason that a seismic ray is normally concave upwards
is due to
(a) the seismic velocity of the earth normally increases with
depth, (b) the seismic velocity of the earth normally decreases
with depth, (c) temperature is increasing with depth, (d) pressure
is increasing with depth.
69. The reason that a seismic ray is normally concave upwards
can be explained by
(a) the law of superposition, (b) the elastic rebound theory,
(c) the Snell's law,
(d) the Hooke's law.
70. Iceland is on top of a
(a) divergent boundary, (b) convergent boundary, (c) transform
boundary,
(d) none of the above.
71. A fault zone like the San Andreas can be (a) a goundwater
barrier, (b) an elongated valley where many sag ponds are found,
(c) a valley where streams are sometimes offset, (d) all the
above.
72. Most of the active volcanoes in Hawaii Islands are found
on
(a) the Big Island, (b) Oahu, (c) Maui, (d) Kauai.
73. Active volcanoes are almost all located in the ___ of this
particular Hawaiian island (a) NE, (b) SE, (c) SW, (d) NW, (e)
Due north.
74. The explosion of the Mount St. Helens is so violent that
its energy release is equivalent to a magnitude ___ earthquake
(a) 5.5, (b) 6.5, (c) 7.5, (d) 8.
75. The magnetic inclination angle i becomes ___ on the (magnetic)
equator.
(a) zero degree, (b) 45 degrees, (c) 70 degrees, (d) 90 degrees.
76. The magnetic inclination angle i becomes ___ at the north
(magnetic) pole
(a) zero degree, (b) 45 degrees, (c) 70 degrees, (d) 90 degrees.
77. The earth's radius is about ___ km
(a) 9750, (b) 6300, (c) 3700, (d) 2100.
78. The radius of the earth's core is about ___ times of the
earth's radius (a) 1.2, (b) 0.75, (c) 0.5, (d) 0.2.
79. In Hawaii, the siren will sound
(a) whenever a missile is fired in the Kamchatka Island of the
eastern Russia, (b) to alert an approaching tsunami, (c) to alert
an approaching volcanic eruption in the Big Island, (d) to alert
a volcano-induced earthquake.
80. In the Pacific coast, if a tsunami warning is received, you
should run away from the beach to a height at least (a) 10 feet,
(b) 30 feet, (c) 100 feet, (d) 300 feet above the sea level.
81. Gouge is a type of (a) volcanic rock, (b) sedimentary rock,
(c) pulverized rock, (d) metamorphic rock.
E. MATCHING
Group I:
83. strike-slip fault a. convergent boundary
84. subduction zone b. divergent boundary
85. Benioff zone c. Transform boundary
86. deep earthquakes d. Hot spot
87. spreading ridge
88. Hawaii Islands
89. Island arc
90. shield volcanoes
91. Himalayan Mountains
Group II:
92. Right-lateral strike slip a. s1 vertical
93. Left lateral strike slip fault b. s2 vertical
94. Normal fault c. s3 vertical
95. Reverse (thrust) fault d. no association
96. Convergent boundary
97. Divergent boundary
98. Transform boundary
Group III: (Figure C)
99. Strike-slip fault
100. Normal fault
101. Reverse fault
Group IV: (Figure D)
102. Strike-slip fault
103. Normal fault
104. Reverse fault
Second Answer Sheet (for Sections A and B)
************************************************************************
Name ______________________ S.S.# ____________________
Name of your TA _____________________________
************************************************************************
1. a. ___________________________________________________________________.
___________________________________________________________________.
1. b. ___________________________________________________________________.
1. c. _______________________________ ; 1. d. _____________________________.
2. a. ___________________________________________________________________.
2. b. ___________________________________________________________________.
2. c. ___________________________________________________________________
_________________________________________________________________.
2. d. ___________________________________________________________________
_________________________________________________________________.
2. e. ___________________________________________________________________
_________________________________________________________________.
3. ___________________________________________________________________
_________________________________________________________________.
4. ___________________________________________________________________.
5. a. ___________________________________________________________________.
5. b. ___________________________________________________________________.
6. ___________________________________________________________________.
7. ___________________________________________________________________.
8. a. ___________________________________________________________________.
8. b. ___________________________________________________________________.
8. c. ___________________________________________________________________.
9. a. ___________________________________________________________________.
9. b. ___________________________________________________________________.
9. c. ___________________________________________________________________.
__________________________________________________________________
10. a. _____________________________: 10. b. ______________________________.
10. c. _________________________________________________________________.
11. ___________________________________________________________________.
12. (1) _____________, (2) _____________, (3) _____________,
(4) ____________,
(5) _____________, (6) _____________.
13. _______________.
14. (1)_____________, (2)______________, (3)______________,
(4)______________,
(5)_____________, (6)______________, (7)______________.
15. _________________. 16. _________________.
17. (1)____________________, (2) ___________________.
18. (1)____________________, (2) ___________________.
19. (a)_____________________, (b)____________________, (c)___________________,
(d)_________________________________, (e)_______________________________,
(f)_______________________________________________.
20. (1)____________, (2)____________, (3)______________, (4)______________,
(5)____________, (6)______________________________, (7)______________,
(8)______________, (9)____________, (10)______________________________,
(11)_____________________________, (12)______________________________,
(13)____________________________. (14) ____________________.
********************************************************************************
Midterm#2
Geology 240 Earthquakes Midterm #2
March 24, 1998 4:00 - 5:20 p.m. SLH 200 Teng
Note: Open-book and open notes.
One point each on your answer sheets unless otherwise indicated.
True or False
1. Volcanoes in Hawaii belong to the type called shield volcanoes.
2. Along the convergent boundary, magma is the darker colored
basalt with low viscosity.
3. The submarine, flat-top volcanoes are called gayots, when
corals grow around the gayots forming ring-shaped islands which
are called atolls.
4. It takes about 2 hours for tsunami waves generated in Chile
to reach Japan.
5. Upon arrival, tsunami waves from big Chilean earthquakes can
cause severe damage on the Pacific coast of Japan.
6. There are many volcanoes on the west coast of the U.S., particularly
in Washington and Oregon states. These volcanoes are evidence
to the subduction of the Juan de Fuca plate.
7. A large part of the energy generated by an earthquake goes
into frictional heat and production of gouge.
8. Higher intensity means higher ground acceleration.
9. Aftershocks are caused by the return of the shock waves to
the epicentral area after they have bounced off on the other
side of the earth.
10. The epicenter always lies on the surface trace of a fault.
11. Volcanic earthquakes release much more energy than tectonic
earthquakes.
12. The largest, most violent Tsunamis are created by strike-slip
faults on the ocean floor.
13. Earth's gravitational attraction = 980 gals. Which is called
1 g.
14. If a recording station registered the arrival times of P
wave and S wave to be tp and ts, then the epicentral distance
is ts-tp.
15. Earthquakes can be located using arrival times of P waves
and S waves at three or more stations.
16. Tsunamis are generally unrecognizable in the open ocean.
17. The great Alaskan earthquake of 1964 generated a tsunami
which actually killed people in California.
18. The origins time of an earthquake refers to the time of P-wave
arrival.
19. Surface wave dispersion has been useful in studying the oceanic
and continental crusts.
20. The surface-wave group velocity dispersion curves are different
for wave paths over the continent and over the ocean; this allows
us to conclude that there is a thin oceanic crust made of basalt.
21. The wave period and wave frequency are related by f x T =
l.
22. If the wave period T = 120 seconds and velocity V = 4 km/sec,
the wavelength are related by V x T = l = 480 km.
23. For a surface wave of period T=120 seconds and velocity V
= 4 km/sec, the
wavelength is about 30 km.
24. Upon arrival, tsunami waves from the Circum-Pacific seismic
belt can cause severe damage on the coastal towns of the Hawaiian
islands..
25. You need at least three seismic station recordings to determine
the magnitude of an earthquake.
26. In the desert, surface fault trace can be located by vegetation
differences across the fault.
27. Fault zone gouge sometimes is a good groundwater barrier.
28. The reason that the ringing of the church bell dies out is
partly because the mechanical vibration energy is absorbed by
the surrounding air.
29. The reason that the earth's free oscillations die out is
due to the attenuation of the earth materials that transform
the heat into mechanical vibrations.
30. For a really large earthquake, the seismic surface waves
can go around and around the earth many times.
31. The strong shaking period (or the damaging portion of the
strong shaking) will last about 5 minutes even for the largest
earthquake.
32. Earthquakes don't kill but unsafe structures do.
33. Short-period surface waves travel slower and have shallower
penetration into the earth.
34. In the least squares method for hypocenter determination,
the process starts out by assuming a trial solution (or a guessed
hypocenter) which may or, more likely, may not be the final answer.
35. The wave PKIKP has gone into both the outer and the inner
core.
36. PcP has a reflection at the inner/outer core boundary.
37. The arrival time of a wave is earlier than the origin time.
38. The arrival time plus the origin time equals the travel time.
39. If you stay farther from a light source, the light intensity
drops off. This is due to attenuation.
40. Short-period earthquake motions attenuate faster than the
long-period earthquake motions.
41. If the Big One occurs some 100 km away, it is the small buildings
in Los Angeles area that would suffer the most shaking damages.
Multiple choices
42. Hooke's law applies to (1) plastic solid, (2) elastic
solid, (3) any solid.
43. Hooke's law says the applied stress is _____ the strain or
deformation.
(1) inversely proportional to, (2) perpendicular to, (3) proportional
to, (4) always at 45o with
44. Snell's law relates (1) angles of incident waves with angles
of reflected and transmitted waves, (2) the traveltime of P waves
with the traveltime of S waves, (3) dip angles with slip angles
(4) dip angles with strike angles.
45. Seismic waves consist of two principal classes (1) Ocean
waves and continent waves, (2) Love waves and S waves, (3) surface
waves and body waves, (4) P waves and S waves.
46. Body waves consist of two types according to the mode of
particle motion and the wave velocity (1) PcP waves and PKP waves,
(2) P waves and S waves, (3) Shock waves and impact waves, (4)
Love waves and Rayleigh waves.
47. Surface waves consist of (1) PcP waves and PKP waves, (2)
P waves and S waves, (3) Shock waves and impact waves, (4) Love
waves and Rayleigh waves.
48. The particle motion of Love waves is (1) longitudinal to
the seismic ray, (2) transverse to the seismic ray, (3) parallel
to the earth's surface and perpendicular to the direction of
wave propagation, (4) retrograde elliptical
49. The particle motion of S waves is (1) longitudinal to the
seismic ray, (2) transverse to the seismic ray, (3) parallel
to the earth's surface and perpendicular to the direction of
wave propagation, (4) retrograde elliptical.
50. The particle motion of P waves is (1) longitudinal to the
seismic ray, (2) transverse to the seismic ray, (3) parallel
to the earth's surface and perpendicular to the direction of
wave propagation, (4) retrograde elliptical.
51. If a is the P-wave velocity, b is the S-wave velocity, we
know that (1) a > b, (2) a < b, (3) a and b are about equal,
(4) all (1), (2) and (3) are possible depending on the region
of the earth's interior.
52. Most of the earthquakes that have occurred in the world are
(1) shallow earthquakes, (2) intermediate earthquakes, (3) deep
earthquakes.
52. For a large earthquake, the ground motion can reach (1) 1
g, (2) 5 g, (3) 10 g,
(4) 50 g
54. Which of the following structures is the least earthquake
resistant (1) wooden frame, (2) adobe, (3) unreinforced brick,
(4) reinforced concrete structures.
55. Damage of an earthquake can come from (1) strong shaking,
(2) fire, (3) flood, (4) all of the above
56. The brittle outer layer of the earth which is broken into
more than a dozen plates is called the (1) crust, (2) lithosphere,
(3) asthenosphere, (4) Mantle.
57. Long term motion across the San Andreas fault takes place
at a rate of about
(1) 5 mm per year, (2) 5 cm per year , (3) 5 m per year, (4)
5 km per year.
58. Which of the following faults is closest to USC? (1) Newport-Inglewood,
(2) Garlock, (3) San Jacinto, (4) San Andreas
59. Tsunamis travel across the ocean at a speed of about (1)
80 m/hr, (2) 800 m/hr,
(3) 80 km/hr, (4) 800 km/hr.
60. The difference in time of arrival of P and S waves (1) is
the same at all distances from a earthquake epicenter, (2) increases
with distance from the epicenter, (3) decreases with distance
from the epicenter, (4) depends only on focal depth and not on
distance from the epicenter
Earthquake ground acceleration is equivalent to (1) force, (2)
energy, (3) velocity, (4) displacement.
61. If the period of a wave is 0.1 second, then the corresponding
frequency is
(1) 1 Hertz, (2) 5 Hertz, (3) 10 Hertz, (4) 50 Hertz.
62. The epicenter of an earthquake can be pinpointed by the use
of
(1) the Richter scale, (2) P and S wave arrival times, (3) telemetry
vectors
(4) soil profiles.
63. The configuration of isoseismals depends upon (1) local geology,
(2) earthquake magnitude, (3) orientation of the fault, (3) all
of the above, (4) none of the above
64. In order to describe the location of an earthquake hypocenter,
one must know the
___ of the focus. (1) depth, (2) latitude, (3) longitude, (4)
latitude and longitude only. (5) all (1), (2) and (3) above.
65. P waves near the earth's surface travels about (1) 90 mph,
(2) 900 mph, (3) 9,000 mph, (4) 90,000 mph.
66. The longest period of earth's free oscillations is roughly:(1)
1 minute, (2) 1 hour, (3) 1 day, (4) 360 seconds.
67. After you have driven a long distance, your tires get hot
even in the winter. This is mainly because of (1) the engine
heat has conducted to the tires, (2) solar radiation, (3) heat
generated by continual deformation of the tires, (4) the concrete
road surface heated up by the sun.
68. It take about (1) 10 minutes, (2) 3 hours, (3) 3 days, (4)
10 hours, for the seismic surface waves to go around the earth
once.
69. If you are inside your home (in California this normally
means a woodframe structure), and a big earthquake hits, you
had better remain there for (1) a minute, (2) 5 minutes, (3)
10 minutes, (4) an hour. After that carefully and swiftly go
outdoors and stay in the open.
70. If a M=4 earthquake releases 6000 units of energy, how much
energy would be
released by a M=3 earthquake? (1) 20 units, (2) 60 units, (3)
200 units, (4) 1800 units.
71. Magnitude determination depends on (1) the distance from
the station to the epicenter, (2) the recorded wave amplitude,
(3) the earthquake intensity, (4) both (1) and (2).
72. Sag ponds are (1) bodies of water found in the desert due
to natural springs, (2) bodies of water in the desert due to
artificial springs, (3) bodies of water found along the aqueduct,
(4) bodies of water found along fault zones.
73. Given log10E = 11.8 + 1.5 Ms, how many Ms = 5 earthquakes
will have their total
energy add up to equal that of a Ms = 7 earthquake? (1) about
10, (2) about 100, (3) about 1,000, (4) about 10,000.
74. Isoseismals are used to describe (1) lines of equal earthquake
intensity, (2) lines equal earthquake epicentral distance, (3)
earthquakes of equal magnitude, (4) seismic waves of equal amplitude.
Fill in Blanks ( 2 points each blank)
75. Examples of dispersion include the fire of a diamond and
the rainbow. These phenomena show that lights of (1)_____________
travel at (2)_______________. Upon refraction, colors spread
out to give the fire of a diamond or the rainbow.
76. Amplitude A of wave motions drops out with distance R from
the source in two ways:
Geometrical spreading, A ~ 1/R; this process is independent of
(1)___________.
Attenuation: A drop off in terms of some exponential function,
with the distance R and frequency f on the exponent. As R (and/or
f) increases, A (2)_________ quickly. This change is especially
rapid when f is high.
77. Give the approximate resonance periods T:
10-story building T = (1) ___ s. (f = ___ Hz)
A 3-sory high home T = (2) ___ s. (f = ___ Hz)
78. Wave attenuation says as waves travel outward from the source,
they heavily lose
The high-frequency energy, which converts into (1) _______ .
That means that if you are at some distance away from a Big One,
you home will (2) ________ affected by the shakings as much as
the (3) _________buildings will at the same distance.
79. Upon tapping it, a real silver dollar (1) _________ very
differently from that by tapping a (2) _______ silver dollar.
This demonstration was meant to show that the vibration frequencies
tell the secret of the (3) ______________ of the coin, even though
the physical size of the two coins are the same.
80. Soap bubbles of different sizes are composed of the same
soapy material, but bubbles different sizes will give rise to
vibrations of (1) ______________ . So, the (2) ________________
also depend on the physical dimensions of an object.
81. With a very large earthquake, the earth will (1) ____________
for several days. This is called earth's (2) _________________.
It has a (3) ___________ of about (4) __________, and numerous
higher modes of oscillations of (5) _______ periods. The collection
of earth's free oscillation periods can be printed out into something
like a (6) ____________ which gives the dimensions and internal
constitution of the earth.
82. If Tp is 8:25:22.34 am, and to is 8:24:11.55 am, then the
traveltime of the P wave is ___________ sec.
83. If Tp is 8:28:18.25 a.m., and Ts is 8:28:24.25 a.m. then
the difference of S-wave and P-wave arrival times is (1) ______
sec; this can be translated into a rough
epicentral distance estimate of about (2) _____ km.
84. Earth's tides is due to ______________________________.
85. Two most important periods of earth's tides are (1) _____________,
(2) _______________.
86. Matching the two sides:
(1) kilo (a) 1,000,000,000
(2) mega (b) 1,000,000
(3) giga (c ) 1,000,000,000,000
(4) tera (d) 1,000
(5) milli (e) 10-3
(6) micro (f) 10-12
(7) nano (g) 10-9
(8) pico (h) 10-6
Calculations, 87 - 89, 3 point each
Given these relations taken from your notes and textbook
Appendix H.
Ms = log10A + 1.66 log10 + 2.0
Mb = log10Az - log10T + 0.01 + 5.9
log10E = 11.8 + 1.5 Ms ( E in Joules)
Where: A = 38 microns for 20 second period Rayleigh wave
Az = 15 microns, period T = 12 seconds
= 40°
Give answers to questions 90 - 92
87. Ms =
88. Mb =
89. E = (give unit)
90. Questions, 3 points each. What are the following relations
stand for?
(1)T = 1/f; (2) f = 1/T; (3) l = V x T;
ALL ANSWERS MUST BE ON YOUR ANSWER SHEETS PROVIDED.
DON'T SUBMIT YOUR TEST SHEETS.
SECOND ANSWER SHEET: TA :___________________________
YOUR NAME:______________________ SS # ____________________________
Fill in Blanks ( 2 points each blank)
75. (1) ______________________________; (2) _______________________________.
76. (1) ______________________________; (2) _______________________________.
77. (1) ________; (2) __________ .
78. (1) __________________; (2) ________________; (3) _______________________.
79. (1) __________________; (2) ________________; (3) _______________________.
80. (1) ______________________________; (2) _______________________________.
81. (1) ______________________________; (2) _______________________________.
(3) ______________________________; (4) _______________________________.
(4) ______________________________ . 82. ______________________________ .
83. (1) ______________________________; (2) _______________________________.
84. ___________________________________________________________________.
85. (1) ______________________________; (2) _______________________________.
86. (1) ____, (2) ____, (3) ____, (4) ____, (5) ____, (6)
____, (7) ____, (8) ____.
Calculations, 87 - 89, 3 point each
87. Ms =
88. Mb =
89. log10E = ; So, E = (give unit)
90. Questions, 3 points each. What are the following relations stand for?
(1)T = 1/f;
(2) f = 1/T;
(3) l = V x T
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Final Exam
(Sample Only) -
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GEOLOGY 240 EARTHQUAKES - FINAL EXAMINATION
Date/Time: May 10, 1999, 4:30 - 6:30 p.m. Professor Teng
Directions
1. Place your name on the answer sheets. Do it now!
2. Two-hour time limit, open-book.
A. TRUE OR FALSE (one point each)
1. Earthquake control is an attempt to modify the nature of
occurrence of earthquakes on known active faults.
2. The possibility of earthquake control was accidentally discovered
at the Rocky Mountain arsenal where toxic waste was pumped deep
into the ground under high pressure.
3. Radon concentration in ground water is being monitored as
one possible earthquake precursor.
4. Special Studies Zone Act regulates the issuance of construction
permits of structures for human occupancy across identified active
faults.
5. Woodframe houses should anchor their structure to the foundation.
6. When a big (M=8) earthquake occurs along the southern section
of the San Andreas fault, the destruction would be far bigger
than a smaller (M=7) earthquake on the Newport-Inglewood fault.
7. During the 1971 San Fernando earthquake, the collapse of the
pre-1933 portion of the VA Hospital accounted for most of the
64 lives lost.
8. An extensive fire broke out after the 1994 Northridge earthquake
because of the Santa Ana condition with strong gusty winds up
to 75 mph.
9. The Van Norman dam came to the brink of failure during the
strong shaking of the 1971San Fernando earthquake.
10. Recently, the Pacific plate plunged under California causing
intermediate or deep earthquakes.
11. If an earthquake is large enough, the City of Los Angeles
could sink into the Pacific Ocean due to liquefaction.
12. To the south of San Bernardino, the San Andreas fault splits
off into several branches, one main branch is called the San
Jacinto fault.
13. The San Andreas fault system terminates when it meets the
Colorado River at the U.S.-Mexican Border.
14. Body waves are waves traveling in the earth's crust and mantle
only.
15. Higher intensity means higher ground acceleration.
16. Aftershocks are caused by the return of the shock waves to
the epicentral area after they have bounced off the other side
of the earth.
17. Energy of a magnitude 6 earthquake is roughly equivalent
to that of about 10 magnitude 5 earthquakes.
18. Scientists think that they can "lock" up a section
of an active fault by pumping fluid into the fault zone.
19. Only rarely do earthquakes occur in the earth's lower mantle
and core.
20. Epicenters always lie on the surface traces of faults.
21. There is a critical fluid injection pressure below which
fluid injection into the fault zone will not trigger earthquakes.
22. Probabilistic earthquake prediction tells us the statistical
aspect of earthquake occurrence.
23. Normal faulting is associated with horizontal extensional
tectonic forces.
24. The largest, most violent tsunamis are created by strike-slip
faults on the ocean floor.
25. Carbon-14 age dating of sag pond deposits along the San Andreas
fault confirms that the recurrence interval for major earthquakes
(M=7.5-8.5) on a given segment of the San Andreas fault is about
145 years.
26. For the most part, all earthquakes larger than M=5.0 have
been shown to be preceded by at least one foreshock.
27. Earthquakes much larger than M= 8.0 have never been recorded
due to the intrinsic sensitivity of modern seismometers.
28. The Special Studies Zones Act outlines the earthquake hazard
zones in which people should not build structures for human occupancy.
29. Maps of the Special Studies Zones of California are available
for general public; it can be purchased from the California Division
of Mines and Geology.
30. The highest earthquake hazard areas are always on hard rock
where structures are firmly coupled to all ground motions.
31. Any formal earthquake prediction in California, made by scientists
or by laymen, must be submitted for State governmental evaluation
by a team of experts.
32. Diagonal bracing in walls is effective in minimizing earthquake
damage to structures.
33. While unreinforced masonry is particularly hazardous, reinforced
concrete has been demonstrated in all cases to be the only better
earthquake resistant construction material.
34. The Benioff zone refers to a major seismic belt in the western
Pacific.
35. Despite of the fact that the Mexico City is about 200 miles
inland, earthquakes that occur along the Mexico's southern coast
have repeatedly caused severe damage at the Mexico City. Coastal
cities such as Acapulco, much closer to the epicenter, have usually
performed much better.
36. All school buildings are supposed to be earthquake proof
to conform to the California Field Act.
37. In the Los Angeles basin, there are at least 14,000 buildings
being designated as ones that do not meet the current earthquake
building codes.
38. As soon as you have felt an earthquake, you should run out
of the build to an open ground.
39. Fire is a real potential hazard for woodframe houses.
40. If the earthquake is large enough, a locomotive engine can
be tossed into the air.
41. There is generally a 10% deductible allowance in earthquake
insurance, which makes it difficult for the owner to collect
if your damage is limited to a loss of a chimney or cracking
of stucco.
42. Anchoring of the sill plate to the foundation and the use
of plywood sheathing on woodframe house are two of the most important
measures to improve the earthquake resistance of a woodframe
house in southern California.
43. Since USC is built on sediment, liquefaction is sure to cause
severe damage.
B. MULTIPLE CHOICE (1 point each)
44. An active fault is defined to be a fault that has movement
during the past (a) 5000 years, (b) 150 years, (c) 11,000 years,
(d) 2 million years.
45. The Special Studies Zone is a region within (a) 1/4-mile,
(b) 1/2 mile, (c) 1/8 mile, (d) 1 mile from the fault.
46. For a 50-story high rise building, its natural vibration
period is about (a) 0.5 second, (b) 2 seconds, (c) 5 seconds,
(d) 50 seconds.
47. Massive tectonic uplift and subsidence occurred during (a)
1964 Alaska earthquake, (b) 1960 Chile earthquake, (c) 1964 Niigata
earthquake, (d) 1906 San Francisco earthquake, (e) a and b above.
48. Which geological formation is the youngest? (a) Tertiary,
(b) Quaternary, (c) Cambrian, (d) Precambrian.
49. Most of the earthquakes that have occurred in the world are
(a) shallow earthquakes, (b) intermediate earthquakes, and (c)
deep earthquakes.
50. The total horizontal displacement over all geological ages
along the San Andreas fault has been (a) 550', (b) 2500', and
(c) more than 350 miles, (d) more than 600 miles.
51. For a very large earthquake, the ground motion can reach
(a) 1 g, (b) 0.3 g, (c) 5 g, (d) 50 g, where g is gravity.
52. The last magnitude 8 earthquake in California was (a) in
1936 at San Francisco, (b) in 1906 in San Francisco, (c) in 1971
at San Fernando, (d) in 1857 at Fort Tejon.
53. Earthquake control means (a) elimination of all earthquake
occurrences, (b) to trade off large earthquakes for a great number
of small and undamaging ones, (c) shifting the possible epicenters
of large earthquakes away from the populatoin, (d) to cement
up the faults.
54. Which of the following structures is the least earthquake
resistant (a) wooden frame, (b) unreinforced brick, (c) adobe,
(d) reinforced concrete.
55. Damage of an earthquake can come from (a) strong shaking,
(b) fire, (c) flood, (d) all of the above.
56. The objective of earthquake engineering is to design and
construct (a) earthquake resistant structures, (b) earthquake
proof structures, (c) structures that will remain stationary
during an earthquake, (d) none of the above, (e) all of the above.
57. During the Peru earthquake of 1970, the town of Yungay was
wiped out, mainly due to (a) severe shaking, (b) fire, (c) landslide,
(d) tsunami.
58. The brittle outer layer of the earth, which is broken into
more than a dozen plates, is called the (a) crust, (b) lithosphere,
(c) asthenosphere, and (d) mantle.
59. Plate movement can be as fast as (a) a few millimeters
per year, (b) a few centimeters per year, (c) a few meters per
year, (d) about 1 km per year.
60. The highest point of the San Andreas fault, where you have
visited in your Spring field trip, is near (a) Bishop, (b) Big
Pine, (c) Palmdale, and (d) Gorman.
61. The duration of the strong shaking period during the 1971
San Fernando earthquake was about (a) 1 1/2 minutes, (b) 5 minutes,
(c) a little more than 10 seconds, (d) 2 seconds.
C. FILL IN BLANKS (one point per blank)
62. A very important fault that goes through the west central
portion of the Los Angeles basin is called (a)___. It is oriented
approximately (b)___ (NE-SW, NW-SE, E-W, N-S). This fault is
primarily a (c)___ fault (thrust, right-handed strike-slip, left-handed
strike slip).
63. The 4 basic structural components of any building are 1.
The distributing structural elements, such as (a)__, 2. The resisting
structural elements, such as (b)__, 3. The (c)__, 4. The connecting
elements such as nailing and joints. A shear wall belongs to
the above components No. (d)________.
64. In the United States, if your home is valued at $250,000,
your annual premium for earthquake insurance is approximately
___.
65. Scientists have demonstrated that earthquakes can be "turned-on"
and "turned-off" by pumping fluid (a)__ and (b)__ the
fault zone.
66. There are two problems that prevent actual experiments of
earthquake control to be carried out along the San Andreas fault:
The first is (a)___; and the second is (b)___.
67. Earthquake insurance in wood-frame dwelling in Los Angeles
metropolitan areas varies from (a) $_______ or less to about
(b) $ ______ per $1,000 of coverage.
68. Scientists are studying 12 categories of earthquake precursors
at the present. Name all of them:
(a)__, (b)__, (c)__, (d)__, (e)__, (f)__, (g)__, (h)__,(g),__
(h)__, (I)__, (j)__, (k)__, (l)__.
69. Construction of a shear wall for woodframe house is accomplished
by nailing plywood sheathing over the 2 x 4 wood frame, at a
maximum nail spacing of ______ inches.
70. According to the Special Studies Zones Act of California,
a active fault trace is bounded by zone boundaries positioned
at about (a) ________ ft. or mile (circle one) on both sides
of the fault trace. Such a map is obtainable from (b)____________
at nominal cost (a few dollars). (c) Give the name (c1) _____________,
(c2) __________, (c3) ____________ of the three maps closest
to USC.
71. What is the potential problem you may have to build a house
on a view lot on the hills in California? Ans. ___________________.
77. Lines of equal shaking intensity are called ___.
72. Name five states in the US other than Alaska and California
which are subjected to seismic hazards (a)__, (b)__, (c)__, (d)__,
(e)__.
73. Properties of the interior of the earth are derived by studying
(a)__ of body waves, (b)__ of surface waves, and (c) ___ of free
oscillations..
74. The four essential elements of a valid earthquake prediction
include: (a)__, (b)__, (c)__, and (d)__.
75. Give the four basic structural components of a building:
(a)__, (b)__, (c)__, and (d)__.
For questions 76 to 86, give the most important damage categories
(A. Strong shaking; B. fire; C. liquefaction; D. tsunami; E.
landslide; F. tectonic uplift/subsidence; G. Very light damage)
of the following earthquakes
76. 1989 Loma Prieta earthquake _____________.
77. 1994 Northridge earthquake _____________.
78. 1995 Kobe earthquake _____________.
79. 1992 Landers earthquake _____________.
80. 1960 Chile earthquake _____________.
81. 1923 Tokyo earthquake ___________
82. 1964 Niigata (Japan) earthquake _____________.
83. 1964 Alaska earthquake ____________.
84. 1971 San Fernando earthquake _____________.
85. 1970 Peru earthquake _____________.
86. 1985 Mexico City earthquake _____________.
87. A Vp/Vs velocity ratio bay refers to ___.
88. The duration time (or width) of the velocity ratio bay is
believed to be proportional to ___________.
89. The return to normal value of the velocity ratio prior to
an earthquake is believed to be caused by ____________.
90. The properties of radon that make it potentially useful for
prediction of earthquakes are (a)__, (b)__, and (c)__.
D. QUESTIONS (5 points each)
91. Give the rationale that we only use the term "earthquake
resistant structures" instead of the term "earthquake
proof structures"
92. What is the message carried by the figure on top of page
95 of your textbook B?
93. What is the message carried by page 121 of your textbook
B?
94 What is the message carried by page 118 of your textbook B?
95. What is the message carried by the map at the top of page
52 of your textbook B?
96. If it takes 30 magnitude (M+1) earthquakes to trade off a
magnitude M earthquake, how many magnitude 4 earthquakes will
it be necessary to trade off the forthcoming Big One (M=8) in
Southern California along the San Andreas fault that may rupture
from Carrizo Plain to San Bernardino?
97. For the above number of magnitude 4 earthquakes to happen
during a period of ten years, what will be the average number
of daily earthquake occurrence? .
98. Name the location and years of the three largest (M >
8) earthquakes in California
D. LESSONS LEARNED FROM DAMAGING EARTHQUAKES --
Describing the slides shown, one point each.
Answer following questions on the Scantron again, by multiple choices or true/false wherever appropriate. You should be able to answer each question in 10 seconds.
99. (a) a big strike-slip fault trace exposed on the Alaska
beach
(b) a thrust fault showing the white portion of the beach being
the subsiding block
(c) a thrust fault showing the white portion of the beach being
the uplifted block
(d) the damage scene of a big tsunami
100. (a) severe earthquake damage due to foundation failure of
poorly consolidated glacial moraine on which these wood frame
houses are built. (b) liquefaction of water saturated soil, (c)
land subsidence, (d) strong uplifting.
101. This is a famous destruction during 1964 Alaska earthquake
in a district of Anchorage called (a) Glacier Height; (b) Turnagain
Height; (c) Glacier Bay; (d) Columbia Bay.
102. The destruction of the Seward train station during the Alaska
earthquake by
(a) tectonic uplifting, (b) liquefaction, (c) strong shaking,
(d) tsunami attack.
103. An important type of damage of the 1964 Niigata earthquake,
that is due to
(a) excessive shaking that has surpassed the strength of the
buildings
(b) liquefaction that caused foundation failure
(c) poor engineering design that caused the weight imbalance
of the buildings
(d) occupants put too much weight on one side of the buildings
104. These "sand boils" are indication of
(a) water pipe ruptures, (b) liquefaction, (c) a landslide, (d)
a tsunami attack.
105. During the 1964 Niigata earthquake, this bridge failed because
of
(a) earthquake induced flood, (b) vertical shaking toss the bridge
spans off the support columns, (c) failure of the support columns
due to liquefaction, (d) none of the above.
106. The town Yungay of Peru, full of adobe houses, was completely
destroyed by exceptionally strong shaking during the big Peruvian
earthquake of 1970.
107. This turns out to be a damage scene of (a) strong shaking,
(b) a tsunami, (c) a landslide, (d) a traffic accedent.
108. The motto of this picture, taken during the 1964 Alaskan
earthquake, is:
(a) "act fast during emergency!", (b) "get out
of a falling building!", (c) "wait a minute!",
(d) none of this nonsense.
109. A scene in the 1906 San Francisco earthquake, these dead
horses remind us that during strong shaking, the downtown streets
are not safe due to falling objects.
110. During the 1971 San Fernando earthquake, the collapse of
the middle building of the VA hospital is a reminder of importance
to bring buildings up to codes.
111. The orange grove shows the displacement of a fault motion
that is
(a) left-lateral strike slip, (b) right-lateral strike slip,
(c) left-lateral reverse, and (d) left-lateral normal.
112. The collapse of this wood frame apartment during the 1971
San Fernando earthquake is because the tenants have overloaded
the second floor with too many heavy appliances.
113. These exploded columns can be avoided by
(a) increasing the spiral steel cross-ties, (b) increasing the
size of the columns, (c) placing steel jackets around the outside
of these columns, (d) all the above, (e) none of the above.
114. This is a picture showing a severe land subsidence problem
that is widespread in the world due to (a) plate tectonic force
slowly acting on landmass, (b) over use of ground water, (c)
normal faulting that forms grabens or depressions, (d) none of
the above.
115. During the 1960 Chilean earthquake, this bus is inundated
by a muddy flood.
116. This is a scene from (a) Kobe, Japan; (b) Oakland, California;
(c) Northridge, California; (d) Landers, California.
117. This is a scene from (a) Kobe, Japan; (b) Oakland, California;
(c) Northridge, California; (d) Landers, California.
118. This is a scene from (a) Kobe, Japan; (b) Mexico City; (c)
Northridge, California; (d) Niigata, Japan.
119. The Kobe destruction has a lot to do with these poorly constructed
wood-frame houses.
120. This is a scene from (a) Kobe, Japan; (b) San Francisco,
California; (c) Northridge, California; (d) Landers, California.
121. This is a picture you may see while you are flying from
(a) LA to Las Vegas; (b) LA to San Francisco; (c) San Francisco
to Salt Lake City; (d) Salt Lake City to LA. It is an excellent
illustration of streams offset by a fault.
F. QUESTIONS (Only students with Engineering and
Science Majors need to complete the following two questions.)
122. If a recording station registered the arrival times
of a P wave and an S wave to be tp and ts, with corresponding
velocity of Vp and Vs, respectively, show that the epicentral
distance D is given by:
Hint: Assuming to is the origin time, then we know:
D = (tp-to) x Vp and
D = (ts-to) x Vs
Try to eliminate to from the above two expressions.
123. Based on the result in question 122, if we assume that
Vp = 5 km/sec, and Vs= 3 km/sec, estimate the epicentral distance
for the seismic station that records the seismogram with the
S wave being 10 s behind the P wave.
Geology 240 Lg Final Exam Spring 1999 Instrucor: Professor
Teng
Your Name ________________ SS# __________; TA Name ___________.
C. FILL IN BLANKS (one point per blank)
62. (a) ______________________________; (b) _____________________________;
(c) ______________________________.
63. (a) ______________________________; (b) _____________________________;
(c) ______________________________.
64. (a) ______________________________.
65. (a) ______________________________; (b) _____________________________.
66. (a) ______________________________; (b) _____________________________.
67. (a) ______________________________; (b) _____________________________.
68. (a) ______________________________; (b) _____________________________;
(c) ______________________________; (d) ______________________________;
(e) _____________________________; (f) ______________________________.
(g) ______________________________; (h) _____________________________;
(i) _____________________________; (j) ______________________________ ;
(k) ______________________________; (l) _____________________________.
69. ______________________________.
70. (a) ______________________________; (b) _____________________________;
(c1) ______________________________; (c2) ______________________________.
(c3) _______________________________;71. ______________________________.
72. (a) ______________________________; (b) _____________________________;
Geology 240 Lg Final Exam Spring 1999 Instrucor: Professor Teng
Your Name _______________; SS# ___________; TA Name ___________.
72. (c) _____________________________; (d) ______________________________;
(e) _____________________________;
73. (a) ______________________________; (b) _____________________________;
(c) ______________________________.
74. (a) ______________________________; (b) _____________________________;
(c) ______________________________; (d) _________________________________.
75. (a) ______________________________; (b) _____________________________;
(c) ______________________________;(d) _________________________________.
76. ______________________________. 77. ______________________________.
77. ______________________________. 79. ______________________________.
80. ______________________________. 81. ______________________________.
82. ______________________________. 83. ______________________________.
84. ______________________________. 85. ______________________________.
86. ______________________________. 87. ______________________________.
88. ______________________________. 89 . ______________________________.
90. (a) ____________________________; (b) . ______________________________.
(c) . ______________________________.
91. ___________________________________________________________________
____________________________________________________________________.
92._____________________________________________________________________
__________________________________________________________________.
Geology 240 Lg Final Exam Spring 1999 Instrucor: Professor Teng
Your Name ________________ SS# __________; TA Name ___________.
93.____________________________________________________________________.
___________________________________________________________________
94.____________________________________________________________________.
___________________________________________________________________
95.____________________________________________________________________.
___________________________________________________________________
96.____________________________________________________________________.
___________________________________________________________________
97.____________________________________________________________________.
___________________________________________________________________
98.____________________________________________________________________.
___________________________________________________________________
122.
123.
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Last modified: April 17, 2000
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