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Posts Tagged ‘bathymetry’

Plate Tectonics and the Seafloor

The people who first mapped the seafloor were aboard military vessels during World War II, using echo sounders  to search for submarines. The results produced a map of seafloor depths. Depth sounding continued after the war. Scientists used this information to produce bathymetric maps of the seafloor. During WWII and in the decade or so later, echo sounders had only one beam, so they just returned a line showing the depth beneath the ship. Later echo sounders sent out multiple beams and could create a bathymetric map of the seafloor below. Using the resources provided, answer the following questions, in complete sentences, on your blog. You may copy and paste these questions and resources, to get you started.

Magnetic Stripes

Magnetic Stripes

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Portion of ocean floor, from Google Earth

Portion of ocean floor, from Google Earth

Research Questions

How can ocean floor features be measured and mapped using current acoustical technology? How can ocean floor maps be used in the commercial, military, and/or private sector?

Objectives

  • Use the description of ocean floor features to construct a three-dimensional model of a section of the seafloor.
  • Simulate active sonar soundings of a model of the ocean floor.
  • Describe the concept of vertical exaggeration and why it is used in construction of side profile maps.

Procedure

In class, we created models of portions of the ocean floor, using playdough, and simulated collecting sounding data in a grid format.

Analysis

  1. Based on your seafloor model provide a description of the topography of your surveyed area.
  2. Using the sonar stick is actually simulating what is known as remote sensing technology. What are the advantages of using remote sensing technology for your survey instead of direct observation?
  3. When graphing the ocean floor features we stretched the Y-axis. This is known as vertical exaggeration. What is the advantage of using vertical exaggeration in constructing your profiles of the seafloor?

Conclude and Communicate

  1. Identify the research questions for this activity, and your ideas/answers to those questions.
  2. Define the following ocean floor features (your model maps contained at least three of them) and provide pictures for three of them:
    1. A flat abyssal plain.
    2. An underwater seamount or guyot.
    3. A continental shelf, break, slope, and rise.
    4. A submarine canyon on the continental shelf.
    5. The mid-ocean ridge.
    6. A trench and island arc system.
  3. Write up responses to the three analysis questions above.
  4. Write two new research questions based on what you have learned from this activity:
  5. What was the value and importance of this activity to your study of science.

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