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How will these stations’ positions change relative to one another?Objective: Learning how Global Positioning Systems (GPS’s) can collect data and can be used to determine the magnitude and direction of movement in the Earths plates.Background information:GPS stations are places located around the world that pick up information from GPS satellites that are orbiting our planet approximately 11,000 miles above Earth’s surface. Generally, three satellites are used to determine points of position change or how quickly Earth’s crust is changing because of plate tectonics of underlying processes of deformation. High precision, satellite GPS’s can calculate position to less than the nearest centimeter. By comparison, hand-held GPS units or driving systems are only accurate to approximately 1 meter.The data that you’ll be collecting from a GPS station will be placed on a time series plot. A time series plot contains an X and Y axis. The X axis (horizontal) represents the date of the daily measurements while the y axis (vertical) represents the station’s position over time using the North, East & Vertical components.The North column represents the distance (in mm) between the unit and the zero point in a North-South direction. Positive values indicate distances north of the zero point; negative values indicate distances south of the zero point. The East column shows how far East (+) or West (-) of the zero position the unit is, and The Vertical column shows how far above (+) or below (-) the zero point the unit is. DATA Sample:63006exampleOriginally uploaded in Earth Exploration Toolbook:Analyzing Tectonic Plate Motion with GPS Data.What does this information mean?On June 30, 2006, the GPS unit was located 1.13 mm south of the zero point, 3.48 mm east of the zero point, and 5.56 mm above the zero point.Data one year later:63007exampleOriginally uploaded in Earth Exploration Toolbook:Analyzing Tectonic Plate Motion with GPS Data.What does this information mean?On June 30, 2007, the GPS unit was located 4.59 mm north of the zero point, 3.95 mm east of the zero point, and 12.33 mm below the zero point.Analyzing real time series data looks like this:Activity:The Earth’s surface is constantly changing due to geological deformation. These changes are caused by earthquakes, volcanic eruptions, and mountain building that occur at plate boundaries. When these changes occur, points on the Earth’s surface change location (north-south, east-west, up-down). By analyzing data collected from GPS stations we can observe these changes by making a time series plot and translate the slope of the plot into the motion of change. While looking at the data there will be outliers (scattered points) which could indicate miscalculations, equipment failure or human error. Procedure:Working with your partner: Selecting a PBO station Go to: the Google Map interface, zoom in on the Pacific Northwest. Locate and click the label of any green bubble other than SEAT. ie: SEATOnce you have selected a station tell your teacher. There shouldn’t be any need for duplication in this activity given the number of stations available.Click on the green bubble to get the station information as shown above.The PBO Station page will show you where this GPS is located. If you click on the picture you can see a close of view. Downloading Dataset and Open it in a Spreadsheet Go back to the Station Information page and click on the Download Time Series Data Excel-compatible formatOpen this file directly into a spreadsheet program: Excel. Save data in your folder, labeling with the station name.Highlight column A, right click, then format cells by clicking on date which is found in the category box. Highlight column B,C & D and then right click, then format cells by clicking on numbers, two decimal points, found in the category box.The following directions will be repeated 3 times, creating three different separate worksheets: North, East & Vertical.Highlight columns A & B, right click, copy, create a new worksheet. Label this North, paste columns A & B in new worksheet.Delete rows 1-8Highlight data in columns A & B, insert scatter chart. A graph will form to the right of the columns. If the data appears squished, pull graph out by the corner until readable. This is a graph showing North-South time series. To read this, a positive slope indicates a North direction while a negative slope would be a South direction.Repeat these directions this time to create a East worksheet. You will need to highlight columns A & C this time. Using steps 1-3 you should create a new graph for East. To interpret direction on a east/west time series, a positive slope indicates a East direction while a negative slope indicates a West direction.For your last graph, repeat steps 1-3 this time highlighting columns A & D. Labe this worksheet Vertical. The line created on this graph indicates up and down movement or plates slipping and sliding (converging, diverging or transforming).Analyzing your graphs by answering the following questions:In the North graph:What are the units of measurement for this time series? mmWhat are the dates of data collection–from when to when? 1/2004 to 4/2010Click on DESIGN and under chart layouts, click on the graph to get a line/gridWhat was the direction of movement, what was the direction and total distance moved in the time measured? movement: S to N; distance: -40mm to 42mm = 82 mmBetween what dates do you see the least slope increase and what was it? 10/06 & 2/08; 10 mmWhat is the approximant average distance of movement for the other posted dates? About 20mm. In the East graph: What are the units of measurement for this time series? mm What are the dates of data collection – from when to when? 1/2004 to 4/2010Click on DESIGN and under chart layouts, click on the graph to get a line/gridWhat was the direction of movement, what was the direction and total distance moved in the time measured? Movement was west to east; distance was -18mm to 18mm = 36mm What is the lowest negative point potted? -17 or -18mm The highest? 16 or 17 mmDoes anything else stand out on this scatter chart in the way of the data not being consistent? What do you think it may mean? There appears to be a less dense area of scatter points around Dec. 2006. That may indicate there was not so much movementIn the Vertical graph:What are the units of measurement for this time series? mmWhat are the dates of data collection – from when to when? 1/2004 to 4/2010Click on DESIGN and under chart layouts, click on the graph to get a line/gridWhat is the average range of movement? Between 20 and -19What is the direction of movement, up or down? down Putting it all together:What is the longitude and latitude of your station?Plot the location of the station on the map for Southern CaliforniaIn the N-S slope, find the average slope by dividing d/t. Don’t forget to tell the direction of movement 4.75 mm/yrIn the E-W slope, find the average slope by dividing d/t. Don’t forget to tell the direction of movement. 13.3 mm/yrLook up converging, diverging or transforming. Which one of these movements is happening at this particular point based on the data collected? Converging: The Washington-Oregon coastline of the United States is an example of this type of convergent plate boundary. Here the Juan de Fuca oceanic plate is subducting beneath the westward moving North American continental plate.What kind of activity causes this kind of movement? Earthquakes, volcanic eruptionsCompare the data collected from a group whose station was above yours and a group who was below yours. In a brief paragraph of 5-10 sentences, describe how your data fits/doesn’t fit a pattern. Can you spot a trend/discrepancy?? Show me8ASI1.3 Use appropriate tools and techniques to gather, analyze, and interpret data. The use of tools and techniques, including mathematics, will be guided by the question asked and the investigations students design. The use of computers for the collection, summary, and display of evidence is part of this standard. Students should be able to access, gather, store, retrieve, and organize data, using hardware and software designed for these purposes. 8ASI2.4 Technology used to gather data enhances accuracy and allows scientists to analyze and quantify results of investigations.8DESS1.1 The solid earth is layered with a lithosphere; hot, convecting mantle; and dense, metallic core. 8DESS1.2 Lithospheric plates on the scales of continents and oceans constantly move at rates of centimeters per year in response to movements in the mantle. Major geological events, such as earthquakes, volcanic eruptions, and mountain building, result from these plate motions. ................
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