Plate Boundary Activity
Name:_________________________
Score:_____/30
Date:_______________Period:_____
Earthquakes occur at different depths beneath Earth’s surface, from just below the
surface to depths greater than 300 km. In this lab activity you will plot and compare real
earthquake data from two convergent plate boundaries where one plate is subducting
beneath the other. One area is the Tonga Islands in the southwest Pacific Ocean; the
other area is along the coastline of Chile in South America.
Procedures:
1. Using the Earthquake Depth Data Table and the graphs on the back of this page, plot
the Earthquake Depth Data for both the Tonga trench and the Chile Trench. DO NOT
CONNECT THE DOTS! Draw a best-fit line for the points. A best-fit line does not go
through all the points, but shows the trend in the data.
2. Using your Plate Tectonics Notes for guidance, label the following on your graphs:
 Write the names of the two plates converging at each location;
 Indicate the direction of movement of each plate using arrows;
 Indicate the type of crust (oceanic vs. continental) for each plate.
Answer each question below using your graphs and your notes.
3. Identify the following as a convergent, divergent or transform boundary:
a.
Mid-Atlantic ridge
b.
Tonga trench
c.
Himalaya Mountains
d.
San Andreas fault
4. Which tectonic plate is being subducted at the Tonga trench? And at the Chile
Trench?
Tonga:
Chile:
5. Compare the distances of the Tonga and Chile trench from the East Pacific Rise –
which is closer and which is farther?
6. If the East Pacific Rise is the source of new oceanic crust, which trench would contain
the oldest rock? Why?
7. Compare the depths of the majority of earthquakes at the Tonga and Chile trench.
Collision of which two types of plates creates the deepest earthquakes?
Credits: Namowitz and Spaulding. Earth Science. Boston: McDougal Littell, 1994.
Osmun, Vorwald & Wegner. Explorations in Earth Science. Albany: United Publishing Co., 1995