Commotion Beneath the Ocean
1. Introduction

Expedition Menu

1. Introduction

2. Theory

3. Formation

4. Evidence

5. Earth's Interior

6. Heat Engine

7. Mid-ocean Ridge

8. On the Ridge

9. Seafloor Spreading

10. Magnetic Field

11. Magnetic History

12. Magnetic Patterns

13. The Plates

14. More on Plates




Don's Introduction

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This expedition makes extensive use of graphics contained in 
"This Dynamic Planet - The Story of Plate Tectonics
An Excellent Publication by  J. Kious and R. Tilling
 of the U.S. Geological Survey.

This expedition should take about 90 minutes to complete, but the next expedition is much shorter.

In this expedition we will examine the creation, evolution and destruction of the crust of the earth below the oceans.   

This process results in the slow, yet powerful, movement of the seafloor as well as the continents -- ultimately, causing the earthquakes that shake the Earth and volcanoes that erupt ash, gas and lava...often creating new rock on the surface of the Earth.  As we will see next week, this process has fundamental consequences for life on this planet.

Expedition Objectives:  Learn about the dynamic nature of the Earth.  Students will come to understand that the surface of the Earth, including that portion under the sea (approximately 70% of the earth's surface), is in a state of constant formation and ultimately recycled back into the interior of the Earth over many ten's of millions of years.  This process has influenced the chemistry of the ocean and atmosphere, and therefore, life on this planet.  It may have even resulted in the origin of life on this planet! 

From "This Dynamic Planet - The Story of Plate Tectonics"   

The creation and movements of the rigid plates that make up the surface of the Earth produce the major volcanic eruptions, such as Mt. Pinatubo in the Philippines (upper left in picture set above).  Mt. Rainier in Washington (upper right) is a constant threat of eruption. Movements of the plates create the major, often destructive earthquakes, such as the 1989 Loma Prieta event (lower left) and the recent tragic events in Indonesia in 2004 and in subsequent years.  Even the growth of the highest mountains on land, such as Mt. Everest (lower right in about pictures), is closely related to the movement of the seafloor.

In many ways, the Earth is alive with activity!  It is a dynamic, ever-changing body that shakes and quakes, giving life and taking life -- it was here long before humans and will remain long after we depart this planet.

Created By:
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Don Reed
Dept. of Geology
San Jose State University
©Copyright 2008
Last Updated on 
Sept. 22, 2008

Is the earth a dynamic or static planet? (select one)

a) it is static with nothing much happening
b) it is dynamic with a mobile surface created by  volcanism, quaking and shaking while it moves 
c) I don't know