Structural geology course for geo majors.

Stress vs force, principal directions of stress, brittle fracture, extension fractures vs shear fractures, focal mechanisms.

In some years, I have used this as part of a homework assignment and, in other years, as part of a take-home exam. It could also easily be used as a class/lab activity.

The primary goal is for students to apply content and concepts that they have already learned, but they also learn about coal mining techniques, mechanisms of mine collapse, and the usefulness of structural geology concepts in another discipline.

Predict the orientation and nature of failure surfaces, analyze a focal mechanism, interpret cause of mine collapse and defend the interpretation with evidence.

Students read a description of the event plus background information on room-and-pillar mining. They predict the orientation and type of fractures that could result in pillar failure, and they use a focal mechanism for the Crandall Canyon event to evaluate whether an earthquake caused the collapse or the collapse caused ground shaking. The focal mechanism is unlike any that they have seen before because it is not a double-couple solution; all first motions are down.

Assignment for Crandall Canyon Mine Collapse case example (Microsoft Word 2007 (.docx) 564kB May9 12)

Students individually submit written analyses with argument and evidence.

Pechmann, James C., Arbasz, Walter J., Pankow, Relu Burlacu, and McCarter, Michael K., 2008, Seismological report on the 6 August 2007 Crandall Canyon Mine collapse in Utah: Seismological Research Letters, v. 79, no. 5, p. 620-636.

Seismic Moment Tensor Report for the 06 Aug 2007, M3.9 Seismic event in central Utah: http://seismo.berkeley.edu/~peggy/Utah20070806.htm

Map of the Crandall Canyon Mine: http://unews.utah.edu/wp-content/uploads/crandall_map_aug_07.jpg

Crandall Canyon Mine Collapse FAQs: http://www.seis.utah.edu/MONRESEARCH/CM/cmFAQ.htm

Earthquakes within 3 km of the Mine: http://www.seis.utah.edu/MONRESEARCH/CM/cm_update.htm

Crandall Canyon Mine collapse update: http://www.seis.utah.edu/MONRESEARCH/CM/Aug6update.htm

Campoli, Alan A., Kertis, Carla A., and Goode, Claude, 1987, Coal mine bumps: five case studies in the eastern Unites States: USGS Information Circular 9149, 39 p.

Arabasz, W.J., Nava, S.J., McCarter, M.K., Pankow, K.L., Pechmann, J.C., Ake, J., and McGarr, A., 2005, Coal-mining seismicity and ground-shaking hazard: a case study in the Trail Mountain area, Emery County, Utah: Bulletin of the Seismological Society of America, v. 95, no,. 2, p. 18-30.