Plate Boundaries Activity
Goal: Compare plate boundaries in a model, using landforms, earthquake depths and volcanoes as evidence of how plates move.
What to do
- Open the Plate Tectonics Explorer with Show earthquakes and Show volcanoes ticked.
- Choose each boundary in the table (type, then plates) and drag the time slider to 20 million years.
- Watch how the plates move. Record the main landforms, the deepest earthquakes (shallow, intermediate or deep, from the color key) and whether volcanoes form.
- Answer the questions. Check your math with the calculator, then try Challenge mode.
Record your results
| Boundary | Main landforms | Deepest earthquakes | Volcanoes? |
|---|---|---|---|
| Divergent: ocean–ocean | |||
| Divergent: continent–continent | |||
| Convergent: ocean–continent | |||
| Convergent: ocean–ocean | |||
| Convergent: continent–continent | |||
| Transform: continent–continent |
Questions
Which two boundaries had the deepest earthquakes? Why can earthquakes there be so deep?
Near a coast, earthquakes get deeper toward the east, under a line of volcanic mountains. What boundary is this, and which way does the slab sink?
Why do volcanoes form at ridges and subduction zones, but not at transform faults like the San Andreas?
Suppose the Mid-Atlantic Ridge spreads 2.5 cm per year. How far apart do its plates move in 10 million years? (1 cm per year = 10 km per million years.)
A ridge spreads 6 cm per year in total (3 cm per year each way). How old is the seafloor 300 km from it?
A classmate says, “The plates float on a sea of liquid magma.” Correct this statement.
Free from Earth Science Lab · earthsciencelab.org · MS-ESS2-3: Analyze and interpret data on the distribution of fossils and rocks, continental shapes, and seafloor structures to provide evidence of the past plate motions. HS-ESS2-1: Develop a model to illustrate how Earth’s internal and surface processes operate at different spatial and temporal scales to form continental and ocean-floor features.