Lab 5 - The Hazardous Earth

100 points - This lab is adapted from the Jules Verne Voyager Jr. Curriculum web site http://www.dpc.ucar.edu/VoyagerJr/pt.html.

We have discussed the Theory of Plate Tectonics in class. In this exercise, you will explore how natural hazards such as volcanoes and earthquakes relate to the earth's plates. We will be using a web GIS run by the UNAVCO Facility in Boulder, CO.

Materials: Before you get started make sure that you have the following materials:

• Goodes World Atlas
• A ruler
• A protractor (yes, the thing that you used in Geometry class!)

Plate Tectonics and Sea Floor Spreading

Go to the Jules Verne Voyager Jr. website at http://jules.unavco.org/VoyagerJr/Earth. Select the basemap Sea Floor Age and add features Tectonic Plates. Click on 'Make Changes'. Turn the legend on by clicking on the 'Legend On/Off' button.

Questions: Answer the following questions in complete sentences. You may want to use your atlas to find geographic locations mentioned. Note that in describing the geographic locations you need to be specific. For example, if you were asked to locate the Mississippi river, an acceptable answer would be 'running north/south in the central United States'. An unacceptable answer would be 'in the middle of the United States'.

1) 5 pts Where is the youngest tectonic plate material found in the Atlantic basin?

2) 5 pts Where is the oldest tectonic plate material found in the Atlantic basin? How old is it?

3) 5 pts Where is the youngest tectonic plate material found in the Pacific Ocean?

4) 5 pts Where is the oldest tectonic plate material found in the Pacific Ocean?

Earthquakes

Select the basemap Gray Topography and add features Earthquakes and Tectonic Plates. You can select more than one option by holding down the ctrl key. Turn the legend on by clicking on the 'Legend On/Off' button.

5) 5 pts What are the locations of the deepest earthquakes?

6) 5 pts What type of plate boundaries are the deepest earthquakes found near (note: You may need to turn off the earthquakes to see the type of plate boundary).

Volcanoes

Select the basemap Gray Topography and add features Tectonic Plates, and Volcanoes. You can select more than one option by holding down the ctrl key. Click on 'Make Changes'. Turn the legend on by clicking on the 'Legend On/Off' button.

7) 5 pts Are all volcanoes found on or near to plate boundaries? Why do you think that this is the case?

8) 5 pts For the volcanoes found on plate boundaries, what type of plate boundary are they found on/near? (note: You may need to turn off the earthquakes to see the type of plate boundary)

Plate Motion

To complete this section you will need a ruler and a protractor.

Protractor refresher

A circle is 360 degrees (360°). If due west is designated as 0°, then 90° points to the north, 180° points to the east, 270° points to the south, and 360° points, once again, to the west. To make a measurement for the following questions I suggest that you print out your screen map and use your ruler to draw a + through the center of each point that you are trying to measure:

Keeping the previous selections (Grey Topography, Tectonic Plates), under 'Velocities' select 'No Net Rotation' and leave the radio button selected on Model (obs or observed just adds a lot more arrows). Again, click the 'Make Changes' button. Measure the rate and azmuth of the arrows located on the North American Plate near Chicago, and on the Pacific Plate near Hawaii. The rate can be estimated by comparison with the 50 mm/yr reference arrow shown in the velocity legend (use your ruler). The azimuth can be measured by using a protractor placed against the screen or printout.

9) 15 pts What is the azimuth and velocity of the Pacific Plate near Hawaii? Calculate each to the nearest whole number.

10) 15 pts What is the azimuth and velocity of the North American Plate near Chicago? Calculate each to the nearest whole number.

The Global Plate motion calculator can be found at http://sps.unavco.org/crustal_motion/dxdt/nnrcalc/. Use Goode's Atlas to look up the latitude and longitude of Honolulu, HI and Chicago, IL. Go to the plate motion calculator and enter the values (just degrees and minutes, leave the seconds blank).