Include your names and periods at the top of this document. Save this document to your harddrive in the
format – platetectonics.lastname1.lastname2
Using Excel to look at Plate Movement
**Go to http://serc.carleton.edu/eet/platemotion/case_study.html and read the case study summarizing how GPS
works to analyze plate movement.
You might have used a Global Positioning System (a “GPS”) to steer you towards a destination on foot or in a car.
Scientists use them for that—and for measuring how a given spot on Earth moves. Their GPS stations are concreted to
the ground so that, as Earth’s crust moves or deforms, the station moves, too. The stations, or “monuments,” detect
crustal movement as little as a few millimeters a year.
Scientists use graphs to show the creeping of GPS monuments. This exercise leads you to make and then to
make sense of these graphs. You’ll begin with simple fictitious data and then you’ll use messier data from GPS stations in
the western United States.
Part 1: Determine the direction of movement of fictitious GPS monuments
1. Download the excel file from the class webpage – “Plate Tectonics Excel Data”
2. As with a car’s GPS, a scientific GPS collects data as coordinates such as latitude, longitude, and elevation.
Scientists convert the data into four components: north, east, vertical, and time.
3. The data in the table A (the first tab at the bottom titled “GPS Monument A” shows how far fictitious GPS
monument A moved each year.
a. The first column shows the time, in years.
b. The other two columns show how far the monument moved in the north-south and east-west
directions, in millimeters.
4. You will make graphs to display and understand this data in Excel. First, the north versus time graph. Highlight
the “Year” column data and the “North” (Do not highlight the titles of the columns, just the data themselves).
5. Go to “insert” at the top of the page and click on “Chart  scatter.” Include a descriptive title, x-axis and y-axis
labels (with units) for your graph.
6. Copy and paste your completed graph into this word document and answer the following questions:
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What direction is GPS monument A moving as time passes? North or south?
Explain how you know this:
What direction would the monument move if the north position decreased from 5 to 0 from year 2000 to
2005?
7. Now you will make a graph for East movement versus time. Highlight the “Year” column data and the “East”
data only.
8. Insert  Chart  Scatter. Include a title, x-axis and y-axis. Copy and paste your completed graph into this word
document and answer the following questions:
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What direction is the GPS monument A moving? East or west?
What direction would the monument move if the East positions decreased from 5 to 0 mm from years 2000
to 2005?
** Make sure you are periodically saving your work!**
9. Now using the data on the second tab “GPS Monument B” create two more graphs (north versus time and east
versus time). Copy both graphs to the word document and answer the following questions:
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Is the north data for monument B increasing or decreasing from 2000 – 2005?
Is GPS monument B moving north or south?
Are the east data values for monument B becoming more positive or more negative?
Is GPS monument B moving east or west?
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Summarize in words what trends in data tell you about the north-south movement of a GPS monument. For
example, “When the values increase over time in the North data, it means that … but when they decrease, it
means that….” Do the same thing for east-west trends.
Part 2: Determine the direction of movement of real GPS monuments
1. Using the data on the 3rd tab, “GPS Station P157,” graph North vs. Time and East vs. Time for GPS Station P430,
northern California.
2. Copy your graphs to this word document after you answer the following questions:
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Is station P159 moving north or south?
East or west?
How do the rates of the north-south motion compare to the rate of east-west motion?
** You can determine the rate by the slope of the line – click the data points  right-click  add trendline
 linear  check “display equation on chart”.
What is the rate (slope) for the north-south movement: _____
What is the rate for the east-west movement: _____
3. Unlike data for monuments A, B, and P157 that were average positions for the year, data for P058 is the
monument’s position on specific dates.
4. Using the 4th tab, “GPS Station P058,” make a North vs. Time graph and an East vs. Time graph. Copy them onto
the word document.
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In what direction is the station moving?
Again, determine the rates of north-south motion and east-west motion using the linear trendline. How
does its rate of motion compare to that of P157?
5. Now graph the vertical data versus time. Copy that graph to the word document.
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How does its graph compare to the other graphs?