NIH Image Fault Investigation Activity Sheet

Background information

Linear features are uncommon in nature, therefore when we examine an image of the Earth, they tend to capture our attention. Viewed from above, certain fault systems appear linear. Geologists use many types of space-bourne images of the Earth to identify faults. Faults are breaks in rock masses along which movement has occurred. A fault zone can be identified by a thin band of crushed rock. The length of a fault may vary from a few centimeters to thousands of kilometers. You can use images of Earth taken from the space shuttle and many other types of images to identify faults breaking the surface of the Earth. Movement along faults causes features that cross the fault to be offset. A stream that crosses a fault will be offset, a tell-tale sign that there is a fault. It can also tell us the relative motion of the fault.
Strike Slip or Lateral Faults are characterized by the horizontal movement of rocks on one side of a fault sliding past rocks on the other side. Many strike-slip faults are associated with plate boundaries and are called transform faults. The San Andreas Fault is a transform fault that is associated with the boundary between the Pacific and the North American Plates. Today we will be looking at several Strike Slip faults as viewed from the space shuttle.

Getting Started

You will be using images, handouts, and maps to identify the region shown in the image and then to identify the faults. Using your maps, you will be asked to determine the approximate orientation and scale of the image.
Start the program NIH Image on your computer. Pull down the File menu and choose Open.
1. Open the file called Fault1.tif.
Examine this image of the Taklamakan Desert Fault in China and identify any linear features you observe.
Draw a line along the fault. Which direction do you think the fault is moving?


2. Open the file called Fault2.tif.
Examine this image of Irrawaddy River Delta in Burma, and identify any linear features you observe.
The image is looking towards the south. Draw a line along the fault.


3. Open the file called Fault3.tif.
Examine this image of Karakorum Fault Zone in China and identify any linear features you observe.


4. Open the file called Fault4.tif.
Examine this image of Black Fault in the Atacama Desert of Chile and identify any linear features you observe.
The Pacific plate is being subducted at about nine centimeters (3.5 inches) per year beneath the South American plate along much of the west coast of South America. Oceanic/continental convergence of this sort characteristically produces elevation and shortening by folding and thrusting. These structures are well developed in the eastern foothills of the Andes. The western parts of the Andes are characterized by more complex structures, and both normal faults (usually suggestive of extension) and strike-slip faults are present. Illustrated in the picture is the trace of the important Atacama fault, which runs for several hundred kilometers parallel to the coast of Chile and the deep ocean trench. The fault is thought to have been active over a long period, and both normal and strike-slip movements have been postulated. Draw a line along the fault, and describe the fault's structure.


5. Open the file called Fault5.tif.
Examine this image of Dead Sea Fault Zone and identify any linear features you observe.
The Dead Sea area is one of the regions most commonly photographed from space. Draw a line respresenting where the fault runs through the picture, and label the Dead Sea and the Sea of Galilee.


6. Open the file called Fault6.tif.
Examine this image of Turkmenistan Fault and identify any linear features you observe.
Look for offset features. Can you see tension fractures? Draw arrows to identify offset features.

7. Open the file called Fault7.tif.
Examine this image of Point Reyes Fault in California and identify any linear features you observe.
Draw a line across the fault. Draw arrows showing the direction of the crustal movement. Do you know that there are two tectonic plates visible in this image? You can see the Pacific plate and the North American plate.
Describe how you think this unique penisula was created.

The next three images are part of a series which follows the Nayband Fault in Iran.
8. Open the file called Fault8.tif.
Examine this image of Nayband Fault, Kerman, Iran and identify any linear features you observe.

9. Open the file called Fault9.tif.
Examine this image of Nayband Fault, Shahdad, Iran and identify any linear features you observe.

10. Open the file called Fault10.tif.
Examine this image of Nayband Fault, Tahrud St., Iran and identify any linear features you observe.

Find the image in which the fault is the easiest to identify, and draw a line along the fault. Look for the image with visible off-set features, and label them.