Afar Field Trip Lab--Draft for Fall 2014
This exercise is entirely individual effort. It will be due at the start of lab Week 3 (details on course syllabus).
Deliverables: Prepare a report on the tectonic features of the Afar region, with diagrams showing how the faults are related to topography in the area. Clearly describe the important characteristics of the earthquakes and faults, and relate them to larger geologic features and processes seen in the local plate boundaries. We will consider this to be a representative sample of the faults in the region, and consider whether features not immediately adjacent to one of the epicenters could be related to faults.
You can cut and paste any of the graphics from the screen into Word, and should aim for the equivalent of at least 1-2 pages of text double spaced. You should not answer the questions directly but should consider this a writing exercise and include your answers into a good, well-organized discussion of what you see, and not just a simple answer to the set of questions.
Fault scarp example to use for inspiration.
Afar was the home of Lucy, Australopithecus afarensis.
Change the program version to geology.
Download the data set inside MICRODEM, with File, Geology lab, Afar. This will download the fairly large data set from the USNA server if it has not been downloaded, and open the project. This includes:
The earthquakes will initially have color coding by focal mechanism.
Plot the earthquake focal mechanisms
Determine the orientation of the focal planes for each of the earthquakes in this region. You will probably want to create a table for your report with this data. You will have to decide if these all have the same general trend, if they belong in several groups, or they are random and each is different.
Geology options and pick Focal plane analysis. This allows you to identify ridges as potential fault scarps. You are looking for ridges parallel to the strike of the faults. While you would love to match the dips, this might not be possible.
Topographic Profiles and then measure the range front scarps.
Aspect Map. This can help to highlight fault scarps, as well as asymmetry in the topography. Steep sides will have narrow bands with the same color for aspect, and the gentler side will have wider bands of a different color.
Questions to consider in your report:
Last revision 7/29/2015