Plate Tectonic - Plate Tectonics (2)
Post Lab 

  • Exploring how the plates have moved through time.
  • Comparing volcanoes and earthquakes to the boundaries of plates.
  • continents
  • earthquakes
  • time
  • volcanoes
  • worksheet

Students locate plate boundaries using earthquakes and volcanoes.


Plate boundaries are marked by numerous volcanoes and earthquakes. The pattern of occurrence of these events is one of the key pieces of evidence for plate tectonics.

In this exercise, the students will examine the pattern of earthquakes and volcanoes at occur in the Atlantic Ocean. Most of these occur at the diverging plate boundary that runs north-south through the ocean. The remainder are at two east-west running transform and converging plate boundaries that goes through the Mediterranean Sea to the east and the Caribbean Sea to the west.

The diverging plate boundary occurs at an underwater mountain range called the Mid-Atlantic Ridge. The center of this mountain range is a low lying area or rift, called the Atlantic Rift Zone. This is the actual plate boundary, and is where most of the earthquakes and volcanoes take place. The shape of this plate boundary mimics the shapes of the continents on either side of it, especially Africa and South America, because these areas of crust were together before the diverging plate boundary formed.


The point of the exercise is for students to see that earthquakes and volcanoes mark the plate boundaries, and that the shapes of the diverging boundaries match the edges of the areas from which they formed.

  1. Tell the students that earthquakes and volcanoes occur within the dotted areas on the worksheet. Make sure that they notice that the continents are not near these boundaries in most places, especially North America, South America, and Africa.

    Tell the students to trace the boundaries of the moving plates by connecting the dots. Ask them if they recognize any connections or patterns between the fit of the continents and the position of the earthquakes and volcanoes. Hopefully they can see that the pattern of earthquakes and volcanoes mimics the edges of the continents. especially between South America and Africa. Tell them that this pattern marks the diverging plate boundary from which these continents, as well as Europe and North America, have split.

  2. Explain to the students that in the Atlantic Ocean this zone of volcanoes and earthquakes is similar to the fit of the continents. Tell them it is called the Atlantic Rift Zone. You may wish to show them maps of the ocean floor and plate boundary.
  3. Draw the diagram. Ask your students to explain what they think will happen if the mantle convection currents pull in opposite directions. Explain that the hot rock will come up and form volcanoes. Ask them where in the Atlantic Ocean area the volcanoes are located. The volcanoes are under the ocean, on the sea floor. Iceland is an exception: here the volcanoes are on land. You may wish to show them the presentation image of the Atlantic Ocean region below. It shows the Mid Atlantic Ridge clearly.

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