This activity utilized Visible Geology and Google Earth to help students understand the limitations of using map-view observations of layer offset to interpret types of faulting. Students create and evaluate three fault models in Visible Geology, and compare their results to actual fault offset patterns seen near Las Vegas Bay, NV.
This is in a senior-level structural geology course for majors.
Skills and concepts that students must have mastered
Students must be familiar with using Google Earth to search, tilt, rotate, and pan. Students may or may not have any prior experience with Visible Geology. Students should know the concepts of heave, throw, and strike separation and should know basic fault terminology (reverse, normal, sinistral, dextral).
How the activity is situated in the course
This activity is situated as a lab within the segment of the course that introduces fault motion, heave, throw, and dip and strike separations.
Content/concepts goals for this activity
Recognizing and measuring fault offset in map view and cross section view.
Making block models with Visible Geology.
Higher order thinking skills goals for this activity
Students synthesize how the rake value in the Visible Geology program influences the type of motion along the fault.
Students evaluate the ambiguities of map patterns of faults.
Other skills goals for this activity
Description and Teaching Materials
For this exercise, you will need to do some exploring of Visible Geology yourself so that you are familiar enough with it to guide the students through its use. The students will make three visible geology models, which I have them print out and annotate with view direction, heave, throw, and strike separation (on the appropriate faces of the block diagram). They will write answers to the questions about the actual and apparent fault slip direction. Finally, they will test their knew respect for fault offset ambiguities on real fault offset patterns near Las Vegas Bay.
Faulty Visualizations Instruction Sheet (Microsoft Word 2007 (.docx) 125kB May1 12)
Las Vegas Bay portion (AI editable) (Illustrator 12.7MB May1 12)
Las Vegas Bay (PDF) (Acrobat (PDF) 12.8MB May1 12)
Entire Assignment (PDF) (Acrobat (PDF) 6.3MB May1 12)
Teaching Notes and Tips
Many students confuse apparent fault slip (the offset they see) with the actual fault slip (the offset dictated by the rake of slip). These instructions reflect and update that attempts to clarify this confusion. Let me know if you think it works, or what I can do to make it even more clear.
I grade students on their models, the answers to the questions, and their evaluation of the Las Vegas Bay faults using a 0-5 rubric.
References and Resources