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Simon Fraser University *
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Course
111
Subject
Geography
Date
Dec 6, 2023
Type
Pages
4
Uploaded by MinisterGrasshopperMaster522
GEOG 111 Fall 2023
Lab 8
Name: Student ID:
TA:
Lab 8 – Response Sheet
Part 1: Identifying the Geographic and Tectonic Settings of Earthquakes
The Canadian Geological Survey monitors earthquakes through a global seismometer network. The locations, depths and magnitudes of Canadian earthquakes can be seen on the NRC website
.
Scroll down to the map depicting all earthquakes of the last 30 days in Canada. 1.
Select the region called “Western Canada” using the region selector at the top of the map. Expand the legend by clicking on it. You can also click on each earthquake dot to see detailed information on that specific earthquake.
Bring up a data table by clicking on the link “List points plotted in the map”. In the data table, click on the heading “Magnitude” to sort the earthquakes by magnitude. Earthquakes are measured on the Moment scale, which can be represented as ML, Mw, or MN in this table, depending on the geographic region.
a.
According to the summary table, what was the magnitude scale of the majority of earthquakes in this region in the last 30 days? (1)
b.
What is the magnitude of the largest earthquake in this region in the last 30 days? (1)
c.
Where was the largest earthquake located? (1)
d.
What was the depth of the largest earthquake? (1)
2.
Now select the region called “Eastern Canada”.
a.
According to the summary table, what was the magnitude scale of the majority of earthquakes in this region in the last 30 days? (1) 1
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GEOG 111 Fall 2023
Lab 8
b.
What is the magnitude of the largest earthquake in this region in the last 30 days? (1)
c.
Where was the largest earthquake located? (1)
d.
What was the depth of the largest earthquake? (1)
3.
Compare your answers from #2 to #1. Give one similarity and one difference between earthquakes in Western Canada vs. Eastern Canada. Explain what accounts for those similarities and differences. (2) 4.
In the pre-lab reading on Canvas, Figure 5 shows a cross section (from A-B in Figure 4) of notable
earthquakes in the Pacific Northwest. Two main groupings of earthquakes are identified on Figure 5 as Group 1 and Group 2. You should also refer to the maps of tectonic plates in Figure 1 and Figure 3 to help you answer these questions.
a.
Which tectonic plates are involved in the seismic activity in this cross section? What type of crust is each plate composed of? (2)
b.
Describe the direction the plates are moving relative to one another, and the geologic/tectonic processes that are creating earthquakes in this area. (2)
c.
Why are the earthquakes in Group 1 deeper than the earthquakes in Group 2? (1)
2
GEOG 111 Fall 2023
Lab 8
5.
Cores obtained from the seafloor off the coast of southern BC and Washington state show evidence of 41 megathrust earthquakes in the past 10,000 years at the Cascadia Subduction Zone (CSZ).
a.
What is the average return period of megathrust earthquakes at the CSZ? (2)
b.
Given that the last megathrust earthquake at the CSZ occurred on 26 January, 1700: in which year do you expect the next one to occur? (2)
c.
How certain are you that the next megathrust earthquake will occur on the date you calculated in 5b? Explain your answer. (1)
Section 2: Mass wasting geomorphology: Case study of the Frank Slide
In Canvas under this week’s Module, open the Google Earth link to the Frank Slide map
. This map shows you the geographic location of the Frank Slide in Alberta.
To get a clearer picture of the scope of the slide from the peak of Turtle mountain, click on ‘3D’ (bottom right-hand corner of map).
To stop the map from spinning, click anywhere on the screen. Use the +/- to zoom in and out as you wish.
Note that as you move your cursor over the map, on the very bottom right-hand corner of your screen Google Earth shows you both the geographic coordinates and elevation at any point.
6.
What is the maximum elevation (metres) of Turtle Mountain? (1)
7.
What is the elevation (metres) at the toe of the debris runout? (1)
8.
What is the relief of the Frank Slide feature? (1)
9.
Use the ruler icon (above the map) to measure the map distance from the peak to the furthest point on the toe of the debris runout. What is the distance in metres? (1)
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GEOG 111 Fall 2023
Lab 8
10.
The Frank Slide took place over a period of about 90 seconds. What was the maximum speed of the slide (in km/hr)? (2)
11.
Calculate the current travel angle for Turtle Mountain (give your answer in degrees and show your work below). (2)
12.
Based on the travel angle and the travel angle of similar historic events in Canada (See Fig. 7 in pre-reading), do you think Turtle Mountain will have another large mass wasting event at this same site in the future? Why or why not? (1)
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