Bridget Garnier

University of Wisconsin-Madison

Undergraduate introductory course in geoscience

Students should be introduced to the different types of faults.

We have used this activity as a homework assignment after the topic is introduced in lecture and reading, but it could also be used in class, in lab, or as group work.

Students will be able to identify the footwall and hanging wall in diagrams or photos of faults.

Students will be able to identify the type of fault shown in a diagram or photo.

Students will be able to predict the motion of fault blocks, given the orientation of the local stress field.

Students will understand that faulted rocks record dynamic geologic processes

This worksheet focuses on understanding the different types of faults. Students learn about normal, reverse, and strike-slip faulting by moving fault blocks in response to different stresses. The first task focuses on dip-slip faults. Students are given 2 sets of fault blocks, each with a moderately dipping fault plane. Students are asked to define which fault block is the hangingwall and which fault block is the footwall by relabeling each fault block correctly. One set of fault blocks (hangingwall and footwall) has arrows that point away from the fault block pair, indicating a tensional environment, while the other set has arrows pointing towards the fault block pair, indicating a compressional environment. Students move the hangingwall of each pair either up or down the fault plane to indicate the correct response to the stress environment. Lastly, students label each fault as normal or reverse.

The second task focuses on strike-slip faults. Students are given 2 sets of faults blocks with a vertical fault plane. Stress arrows indicate either a sinistral or dextral stress environment. Similar to the first task, students move one of the fault blocks in each pair in the correct direction as indicated by the stress arrows. Lastly, students either label the fault as sinistral or dextral. After all tasks are complete, students answer 3 multiple-choice questions.

This worksheet uses the sketch-understanding program with built-in tutor: CogSketch. Therefore, students, instructors, and/or institution computer labs need to download the program from here: http://www.qrg.northwestern.edu/software/cogsketch/. At any point during the worksheet, students can click the FEEDBACK button and their sketch is compared to the solution image. The built-in tutor identifies any discrepancies and reports pre-written feedback to help the student correct their sketch until they are done with the activity. Once worksheets are emailed to the instructor, worksheets can be batch graded and easily evaluated. This program allows instructors to assign sketching activities that require very little time commitment. Instead, the built-in tutor provides feedback whenever the student requests, without the presence of the instructor. More information on using the program and the activity is in the Instructor's Notes.

We have developed approximately two dozen introductory geoscience worksheets using this program. Each worksheet has a background image and instructions for a sketching task. You can find additional worksheets by searching for "CogSketch" using the search box at the top of this page. We expect to have uploaded all of them by the end of the summer of 2016.

CogSketch has a gradebook feature that allows instructors to batch grade worksheets using the defined rubric in the worksheet. Once graded, instructors can also open all the sketches and evaluate student work. Instructions are given in the Instructor's Notes.

Download CogSketch: http://www.qrg.northwestern.edu/software/cogsketch/