These photos were taken on a Geological Society of America field trip, October 15, 2005, run by Ron Bruhn, Christopher DuRoss, Ronald Harris and William Lund.
|The Wasatch Front at Provo.|
|Views of the Wasatch Front from a city park in Provo. The Y, of course, is for Brigham Young University, and the mountain is Y Mountain. Y not?|
|Perched on the hillside (far left center in the view above) is a boulder field, remnant of an ancient landslide.|
Here's why I post Web pages. This amazing scarp was exposed during excavation for a ski resort that never came off. The city sold the land to private developers who are now building along the scarp. (Building codes along the fault prohibit straddling the fault but have few restrictions on proximity to the fault. As for seismic safety, the house here is probably safer than many farther away on deep alluvium.)
The present owner of the lot (Fall, 2005) is hospitable to field trips, but there are no guarantees access will always be easy or possible, or even that the outcrop won't be buried or excavated. So document it while we can. On the other hand, this exposure would never have become known without development.
|The exposure shows an astonishingly smooth rock surface.|
|Just south of the outcrop the scarp is impressive but gives no clue how remarkable the slip surface really is.|
|If this were in Wisconsin I would swear it was glacially polished.|
|The rock itself is breccia with pervasive slickensides. The breccia probably represents brittle failure at a deeper crustal level and the smooth surface represents localized Quaternary slip.|
|The Wasatch fault is actually a low-angle normal fault dipping 30-40 degrees west, and here the extension created a small horst, which is transected by a ravine.|
|The gray horst contrasts with the surrounding materials, making it a horst of a different color. (Thanks, folks, you're a great audience. Put the rock pick down, sir.)|
|Distant views of the scarp and horst.|
Bruhn, R. L., DuRoss, C. B., Harris, R. A., and Lund, W. R., 2005; Neotectonics and Paleoseismology of the Wasatch Fault, Utah, in Pedersen, J. and Dehler, C. M., eds., Interior Western United States: Geological Society of America Field Guide number 6, p. 231-250, doi: 10.1130/2005.fld006(11).
Created 18 November 2005, Last Update 01 July 2012
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