Lab 8 - Earthquakes and Seismicity - F23
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New Jersey Institute Of Technology *
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Course
342
Subject
Geology
Date
Dec 6, 2023
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docx
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Laboratory 8 Earthquakes and Seismicity CE 342 - Geology
Fall 2023 - Dr. John Schuring
1.
In the long past there was no Atlantic Ocean because all the world’s continents were joined together to
form a single supercontinent called “Pangea.”
Then, plate tectonics caused South America to begin
moving away from Africa, as well as North America moving away from Europe.
Thus, the middle of the
current Atlantic Ocean represents a divergent plate boundary because the continents on the eastern side of
the ocean are drifting away from the continents on the western side (see figure below).
Since the continental spreading began, its rate has averaged about 3 cm per year. Assuming that the
rate has been constant, estimate the age of the Atlantic Ocean.
State and document any assumptions, and
show your calculation
.
2.
Answer the following questions based on a viewing of the PowerPoint presentations
:
A.
The general cause of earthquakes on a worldwide basis is ______________
____________?
B.
Mathematically, the Richter scale is considered to be ___
logarithmic
____ rather than linear.
C.
What type(s) of seismic wave causes the most damage to structures? _
Love and Rayleigh Waves
_
D.
As the density and strength of a geologic formation increases, the amplification and damage potential
for seismic waves _____________________?
E.
The natural vibration frequency of most structures is in what range?
How does this compare with the
resonant frequencies of different kinds of geologic formations?
F.
Order the following construction types according to seismic resistance, from best to worst
: steel
frame, reinforced concrete, unreinforced masonry, wood?
G.
What kind of geo-hazard may occur in saturated sand?
H.
Upon their retreat and melting, the glaciers left behind many glacial lakes.
When a glacial lake
occurred near the ocean, it tended to contain sensitive (“quick”) glacio-marine clays.
Explain the
engineering concern with these quick clays.
I.
True or False? As a tsunami wave approaches the shoreline, both its height and speed increase.
True
J.
If you are near the ocean in a tsunami-prone region, and you experience an earthquake that either
knocks you off your feet or has a duration of >20 seconds, you should immediately move _____
(distance?) inland or _____ (height?) higher in elevation for your personal safety.
3.
How many ergs
of energy does an earthquake with M=4 release?
How about an earthquake with M=5?
So, how many times more energy is released by the M=5 quake compared with M=4 quake?
What would
be the energy multiplier if the difference was two magnitude units, that is from M=4 to M=6?
Show all
calculations
.
4.
Using the California Code information discussed in class, determine the following seismic design factors
and coefficients for a new Civil Engineering Residence Hall (Hooray!) to be constructed on the NJIT
campus.
Assume that the building will be a five-story, reinforced masonry building founded on Mudstone
bedrock (similar in properties to a Limestone since both are sedimentary). Make sure to show all
calculations or cite
table sources
.
A)
What is the Seismic Zone according to the code?
B)
What is the likely Wave Frequency of the bedrock?
C)
What is the Structure Response Factor according to the code?
D)
Estimate the Wave Period Factor for this five-story building.
Now assume that the same residence hall will also be built in two other cities, Los Angeles, CA, and
Dallas. TX (assume similar site geologies as in Newark). Which of the seismic factors will change, and
what will be the values?
DUE ON Tuesday, November 21
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