G131 HOME
INFORMATION
SCHEDULE
RESOURCES
EXERCISES
EXERCISES
Examination and evaluation of real-time oceanographic data on the internet
PRELIMINARY
I: TECTONICS
and OCEAN BASINS
Earthquakes and Plate Tectonics
Spreading Rates
CA Earthquakes
Volcanoes
Topography of the Ocean Floor
History of Ocean Basins
II: OCEANS/ ATMOSPHERIC GASES
III: OCEAN/
ATMOSPHERE DYNAMICS
IV: INTEGRATED TOPICS
 
TOPOGRAPHY OF THE OCEAN FLOOR (indiv.)

Introduction to Questions on the Topography of the Ocean Floor:

  • The questions are outlined in three separate tables:
  • Reminder: you should submit your answers via oncourse .
Procedures:
  • The site requires a response to the various options regarding plotting parameters for the topographic images
  • The selection of some of the values is based on the values given in each question. 
    • latitude, longitude and maximum depth
    • southern latitudes should be entered as negative numbers
    • western longitudes should also be entered as negative numbers
    • note that these window are narrow and not all of the numbers may show.
    • an error message will be received if any values are erroneous
  • Other values should be set to the following recommendations:
    • view angle: set at values of 00 for horizontally and 70 for vertically
    • aspect ratio: keep at the default value of 1
    • dataset selection: keep at the default selection of etopo5
    • increase the specified image size to a factor of 2.0
  • Generation of the map image may take a few seconds
Topography of the Ocean Floor (contd.) pt
3D Seafloor Topography: Mid Ocean Ridges
Enter the site entitled " Three-dimensional bottom topography " and make selections of plotting parameters according to the specifications given above and values for latitude, longitude and maximum depth given in the tables below.
Examine the seafloor topographic map for the following three locations on mid-ocean ridges. 
5. Describe the height of the ridges in km and their approximate width in °longitude.  HINT

location
latitude range
longitude range
depth (m)
(a) mid-Atlantic Ridge
20°N
35°N
55°W
35°W
8000
 2
(b) East Pacific Rise
 45°S
30°S
120°W
100°W
6000
 2
(c) mid-Indian Ridge
25°S
10°S
60°E
80°E
6000
 2
6. What are the ranges of values for the heights and widths of the spreading ridges?
2
7. What tectonic controls determine the breadth and elevation of a spreading ridge?  HINT
3*
3D Seafloor Topography: Trenches
Examine the seafloor topographic map for the following three locations at oceanic trenches. 
8. Describe their depth range (plain to trench bottom) on both sides of each of the trenches and their width in °longitude. HINT

location
latitude range
longitude range
depth (m)
(a) Marianas Trench
13°N
28°N
140°E
160°E
10000
3
(b) Kermadec-Tonga Trench
35°S
20°S
160°E
180°
8000
3
(c) Peru-Chile Trench
30°S
15°S
90°W
70°W
6000
3
9. Do the trenches tend to be symmetrical?  HINT
3
10. How do the comparative depths on either side of the trench relate to the directions of plate motion?  HINT
2*
  << Back
 
 
Continue >>
Indiana University
Department of Geological Sciences, 
1001 E. Tenth Street, Bloomington, IN 47405-1403
Phone: (812) 855-5582  Last updated: 6 October 2002
Comments: simon@indiana.edu
Copyright 2000, The Trustees of Indiana University