The Web is a wonderful resource for exploring places you might not otherwise be able to visit. How often, for example, do you get to visit a volcano, let alone a volcano erupting approximately 2,300 meters (~1.5 miles) below the surface of the sea? For this portion of your research, you’ll investigate the dynamic forces at work in the deep seas, including the submarine (underwater) volcanoes and submarine earthquakes that are the direct result of plate tectonics.
To conduct your investigation, work as a scientist does—make observations and record what you see. Look for patterns. Afterwards, question those patterns, exploring what they might mean and how they apply to your understanding of submarine volcanoes, mid-ocean ridges, and deep sea vents.
You’ll start your investigation by gathering some background information on submarine volcanoes and mid-ocean ridges. First, find out what they are. Bring your journal to the computer and go to the following address below:
From there, you can click on “world ridge system” and “spreading” to find out more. Take notes on your discoveries, using the questions below to structure your investigation. Next, visit:
Read through the overview section; click on “mid-ocean ridge systems” and “recent submarine eruptions” to find out more. Under “recent submarine eruptions,” you can click on specific recent eruptions to get more information, including seismic graphs, maps, animations and descriptions. Examine the epicenter maps (such as the one included with the Middle Valley page) to find out how many earthquakes have occurred and also how the location of epicenters has moved over time. How are these earthquakes related to mid-ocean ridges?
Conducting research on the Web means that you can even hear sounds from the deep ocean! Listen to underwater seismic activity at:
To make sure you know which sounds are seismic activity and which are the background noise of the deep ocean, you can compare the underwater seismic activity sounds with the recorded sounds of whales in the deep ocean.
Submarine volcanic activity is very different from volcanic activity on land; the near freezing temperature of the water and the incredibly intense pressure of the deep seas change things quite a bit! Comparing recently formed rocks from submarine volcanoes with recently formed rocks from land volcanoes will help you understand submarine volcanoes more deeply. It always helps to start with what you know; in this case, start with land volcanoes, which are probably more familiar to you than submarine volcanoes. Check out:
Here you’ll find photographs of recent subaerial (on land) volcanic eruptions in Hawaii. This site is updated almost daily; you can look at photographs taken in the last week, or check out the archived photos. Examine the images of lava flows and of other recently formed volcanic rock; in your notes, describe what you see and explore how volcanic rock moves and hardens on land.
Now you’re ready to compare land volcanoes with deep sea volcanoes. First take a look at a photograph from Hawaii; this photo shows the lava and heat from under water, instead of on land:
This image shows pillow lava that formed in very shallow water, as you can judge by the snorkeler swimming near by. To see pillow lava that formed at the deep sea ridges, you’ll have to go much deeper in the ocean! Check out the following site:
Click on “pillow lava” and “sheet flow” to see images of submarine volcanic rocks. You can also see an animation showing how sheets form at:
And you can read the “Rumbleometer Story,” about how an deep sea research tool got caught in a submarine volcano—and “lived” to tell the tale!
Finally, if you still have time, watch deep sea vents in motion! Go to:
You can click on a variety of titles to see real-time videos from the deepest depths of the sea!
If you’re working with a team, discuss your observations with your teammates; just make sure to record in your own journal your observations about the deepest depths of the sea. Use the questions below to guide your investigation.
- What percentage of the world’s volcanic eruptions take place on the sea floor? Does that figure surprise you? What tools allow scientists to “watch” these eruptions, since they can’t directly observe them?
- What did you discover about deep sea earthquakes? Consider how many there are and how the location of activity changes over time.
- Why do you think earthquakes and volcanoes occur at the mid-ocean ridges? Think about the pattern of earthquake activity and the location of submarine volcanoes at the mid-ocean ridges. How is this pattern related to plate tectonics? Why are mid-ocean ridges “shaped” the way they are?
- Describe lava flows from subaerial volcanoes. What does the lava look like as it erupts? How does the lava flow? How does it harden? Compare volcanic activity on land with submarine volcanic activity. How does lava “erupt” differently in the deep ocean? How does it spread? Into what shapes does it harden, and how are those shapes different from the hardened volcanic rock you might see on land?
- Submarine volcanoes are not deep sea vents. What is the relationship between the two? Define each so that you understand the difference. How are the dynamic forces of shifting plates related to deep sea vents?