How Do Scientists Determine the Boundaries of the Earth's Plates?

Background

Scientists discovered that when the locations of earthquakes were plotted on a world map, these locations occurred in a pattern, or variety of patterns. These patterns led scientists to believe that the earth's crust is divided into different sections, or plates. The theory of plate tectonics states that the earth's crust is broken into moving plates. Six of the seven major continental plates are named for the continents where they are located. The seventh continental plate, the Nazca Plate, is located between the South American and Pacific plates. The three types of plate boundaries — divergent boundaries, convergent boundaries, and transform boundaries — describe how two plates move relative to each other. By plotting the locations of earthquakes, scientists have not only been able to locate plate boundaries but have also been able to determine plate characteristics and predict the movement of the plates. In this investigation, you will plot the locations of earthquakes and determine the boundaries of the earth's plates.

Objectives

After completing this investigation, you will be able to:

Procedure

  1. Following is a list of geographic coordinates of earthquakes. Plot the location of each earthquake on the map by placing a dot where the longitude and latitude coordinates intersect. After you have plotted the coordinates, connect them to form a curved line.
    Latitude Longitude
    75°N
    70°N 15°W
    60°N 29°W
    55°N 30°W
    45°N 40°W
    35°N 40°W
    20°N 40°W
    15°N 30°W
    20°W
    Latitude Longitude
    15°S 20°W
    30°S 20°W
    40°S 28°W
    45°S 30°W
    55°S 40°W
    60°S 60°W
    40°S 90°W
    35°S 120°W
    45°S 135°W
    50°S 150°W


  2. Plot the following earthquake coordinates and then connect them.
    Latitude Longitude
    35°N 30°W
    35°N 10°W
    35°N
    35°N 15°E
    30°N 30°E
    25°N 40°E
    10°N 45°E
    Latitude Longitude
    5°N 60°E
    10°S 70°E
    30°S 45°E
    48°S 30°E
    50°S 0°E
    47°S 20°W

     
  3. Plot the following earthquake coordinates and then connect them.
    Latitude Longitude
    15°N 55°W
    15°N 65°W
    Latitude Longitude
    15°N 75°W


  4. Plot the following earthquake coordinates and then connect them.
    Latitude Longitude
    50°N 170°W
    55°N 150°W
    45°N 125°W
    30°N 115°W
    20°N 105°W
    Latitude Longitude
    15°N 90°W
    5°N 75°W
    15°S 70°W
    30°S 75°W
    45°S 75°W


  5. Plot the following earthquake coordinates and then connect them.
    Latitude Longitude
    60°N 180°E
    55°N 150°E
    45°N 130°E
    30°N 125°E
    15°N 120°E
    120°E
    10°S 135°E
    15°S 160°E
    Latitude Longitude
    30°S 165°E
    50°S 160°E
    55°S 135°E
    50°S 110°E
    40°S 80°E
    20°S 75°E
    15°S 65°E


  6. Plot the following earthquake coordinates and then connect them.
    Latitude Longitude
    30°N 45°E
    30° N 60°E
    30°N 75°E
    20°N 90°E
    Latitude Longitude
    15°N 95°E
    105°E
    5°S 120°E


  7. Listed below are six of the seven major continental plates that scientists have identified. The continental plates are named after the continent that is located on the plate. Write the names of the following continental plates in the proper places on your map. The seventh plate, the Nazca Plate, is identified for you. The six plates you must label are the:
    1. North American Plate
    2. South American Plate
    3. African Plate
    4. Eurasian Plate
    5. Indo-Australian Plate
    6. Antarctic Plate