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7. Earthquakes and Plate Boundaries Beneath the Atlantic Ocean

Expedition Menu

1. Introduction

2. Global Distribution

3.  Earthquakes & Plate Boundaries

4. The Ring of Fire

5. Convergent Boundaries

6. Atlantic Ocean

7. Atlantic Ocean II

8. Alaska Earthquake

9. Vertical Slice

10. 3-D Look

11. California Plate Boundaries

12. Mendocino Triple Junction

13. Could it Happen Here

Animation by
Educational Multimedia Visualization CenterDepartment of the Geology
University of California, Santa Barbara

Voice over by Don Reed

Yes, it is a divergent plate boundary in the middle of the Atlantic Ocean along the mid-Atlantic ridge.

Examine the sketch below, which is a cartoon-like diagram depicting one segment of the Mid-Atlantic Ridge.

You are looking straight down on a map of two divergent plate boundary segments that are connected by a single east-west trending transform plate boundary. 

Next, put arrows on diagram in your worksheet that show the direction of plate motion (remember that plates move parallel to transform faults and away from divergent plate boundaries)

Put an X on the north side of the fracture zone on the right side of the diagram and a Y directly across from the X, on the other side of the fracture zone 

Which letter lies on the older oceanic crust?

Which letter lies on the colder oceanic crust?

Which letter lies on oceanic crust of greater density?

Which letter lies at a greater water depth along the sea floor? 

(Hint: Remember  D=2500 + 350 T^1/2)

Contact Don Reed
Dept. of Geology
San José State University
©Copyright 1999
Last Updated on June 21, 1999

Why are there few, if any, earthquakes located along the fracture zones in the Atlantic?

a) because that is the way it is
b) because the fracture zones are not plate boundaries and only mark a change in the age of the oceanic lithosphere within the same plate