1. Faults & Topography

2. What’s a Fault?
A fault is a break in the rock that makes up the Earth’s crust.
The surfaces on either side of the break move past each other, becoming displaced.
Animation: one mouse click shows animation of a fault.
Imagine that the brown rectangular box is a cross sections of the earth’s crust. Watch the fault form!

3. Types of Faults Dip Slips Change in vertical direction (up and down).
Thrust Fault
Animation: One mouse click shows animation of the fault on the left. Another mouse click shows animation of the fault on the right.
With a dip slip, one side ends up higher than the other. There are two kinds of dip slips: a normal fault and a thrust fault. In a normal fault, the moving piece moves downward. In a thrust fault, the moving piece thrusts upward.
Normal Fault

4. Types of Faults Strike Slips
Change in horizontal direction (side to side).
Right-lateral
Animation: one mouse click shows animation of the fault on the left. Another mouse click shows animation of the fault on the right.
With a strike slip, one side ends up to the left or right of the other.
A strike slip can have left-lateral or right-lateral movement. If you image that you’re standing on the side of the fault that doesn’t move and look directly across the fault, the direction that the opposite side moves defines whether the movement is left-lateral or right-lateral.
So for the faults on the slide, picture yourself standing where the cartoon person is. Which fault is left-lateral and which one is right-lateral?
Left-lateral

5. To learn more about Plate Boundaries, click here.
What Causes Faults?
Stresses and strains on the earth’s upper layers create breaks (faults) in the earth’s crust. These stresses are caused by things like:
Plate boundary movements
Thermal expansion and contraction
Gravitational forces
If your class hasn’t yet studied plate boundaries and plate tectonics, this website is a good resource: You can also go through the Supplement “Intro to Plate Tectonics” by clicking on the link on this slide.
Tell the students that while the earth seems rock solid to us, it shifts and move under great amounts of force. If you have a sponge or latex rubber glove, you can perform these visual examples of forces that cause stress/strain:
Sponge: Push the two ends of the sponge together. Point out how the middle part rises up as a result of the force.
Latex Rubber Glove: Mark the latex rubber glove with a black line. Stretch the latex by pulling both ends. Point out how the black line stretches and thins out.
A Brief Explanation of Plate boundaries: The earth’s lithosphere (top layer of the earth composed of crust and mantle) is divided into plates that very slowly move in relation to each other over the core of the earth. These movements along plate boundaries cause the deformation of the earth. Plate tectonics is now the predominant theory for explaining phenomena such as the occurrence of earthquakes, the formation of mountains, and the formation of faults.
To learn more about Plate Boundaries, click here.

6. Faults Across the Globe
Faults were found near Kaliningrad, Kaliningrad Oblast, Russia.
Kaliningrad Oblast is an exclave of Russia in Eastern Europe. Kaliningrad is a major city in Kaliningrad Oblast. An earthquake occurred in this region in 2004, and the following pictures show faults that were found in the community of Lyublino (approx. 12 miles from Kaliningrad).

7. Faults Across the Globe
Faults possibly due to earthquake in 2004.
Pictures by Professor Grigory Koff, Geological Institute Russian Academy of Sciences. Found at:

8. Faults Across the Globe
Pictures by Professor Grigory Koff, Geological Institute Russian Academy of Sciences. Found at:

9. Faults Across the Globe
Pictures by Professor Grigory Koff, Geological Institute Russian Academy of Sciences. Found at:
Answer: a normal dip slip fault
What kind of fault is this?

10. Faults Across the Globe
San Andreas fault in California occurred as a result of the 1906 San Francisco earthquake.

11. Topography Topography is the study of the earth’s surface.
A Topographic Map is a representation of the earth’s 3-D surface on a flat piece of paper.
Topographic Maps show important geographical features, landmarks, and land contours.
Land contours are shown by contour lines.

12. Topographic Map
Contour lines are curves that connect congruent points of the same altitude.
Rules of Contour Maps:
The Rule of O’s
The Spacing of Contours
The Contour Interval
The Rule of O’s: Closed loops are normally uphill on the inside and downhill on the outside. The innermost loop is the highest altitude.
Spacing of Contours: Close contours indicate a steep slope. Distant contours represent a shallow slope.
The Contour Interval: The distance between contour lines that are next to each other is called the contour interval. Usually, contour intervals are consistent throughout the map, and the value is given at the bottom of the map (e.g., CI: 50 ft). Some maps will use dashed lines to represent half the contour interval distance.

13. Topographic Maps Contour Line
This topographic map shows Stowe, Vermont, USA (from USGS). Point out the contour lines to students and tell them the contour interval is 20 feet. Ask the students what kind of geographical features this topographic map shows. (Possible Answers: river/stream, roads, lakes/ponds, city name, land contours, hills).
The red circled area shows contour lines that are very close together. What does this mean? (Answer: This is a steep area. If each contour line represents another 20 feet in elevation, then having many contour lines close together means the rate of elevation change is greater.)
Point out the faintly written numbers along the contour lines (e.g., 1000, 700, 900). One is circled in blue. Ask the students what they think these mean. (Answer: the altitude of that contour line).
Ask the students: Is the city of Stowe at a low point or a high point?/Is it on a hill or in a valley?/Is it at the highest elevation around or one of the lowest? How do you know? (Answer: The contour lines show it at a lower elevation.)

14. Topographic Maps
This shows the same topographic map next to a shaded relief version. This will help the students see how the original topographic map follows the terrain. Point out the red circled areas. The original topographic map shows close-together contour lines. The shaded relief map has a correspondingly steep area there.

15. What are some major differences between these topographic maps?
These two topographic maps from Topozone.com show Boulder, CO (bottom left) and College Station, TX (top right). The scale is the same for both (at the bottom of both maps).
Ask the students what kind of differences they can see between these two cities’ topographies. Point out that Boulder is at the base of Rocky Mountain National Park and the line of the Rocky Mountains. College Station, however, is in central Texas – a much flatter area of the nation.

16. How’s It Used?
Can you think of some ways a topographic map might be used?
Topographic Maps are used in:
Geographic Planning
Architecture
Civil Engineering
Earth Sciences
Mining
Hiking
Ask the students “What are some ways you think topographic maps are used?” After giving them a chance to answer, click the mouse to show the bullet pointed list of uses.