Spatial and temporal evolution of intracontinental shear zones: The Stateline fault system, Eastern California Shear Zone (USA)
Zusammenfassung der Projektergebnisse
This project involved a short-term preliminary study of the Stateline fault system, which lies on the California-Nevada border, USA. The basic aim of this project was to collect preliminary geologic, tectonic, and geophysical (small seismic survey) data along this fault system with the goal of producing a new geologic map for this fault zone and laying the ground work for a larger project focused on determining the slip-rate of this fault and on understanding this faults role in accommodating North America-Pacific relative tectonic plate motion. Though the geophysical aspect of the project was not successful due to logistical problems the geological part of the project was successful and resulted in a geological map of a portion of the fault zone that can be downloaded from the web (http://web.mac.com/tectonite/iWeb/Site%204/Downloads.html). This map forms the basis of an ongoing study into the processes affecting fault scarp degradation over time and a project focused on using very high-resolution digital terrain models (a digital model of the landscape that includes topography as small as 30cm high) to analyze fault scarp populations. Fault scarp analyses are useful because they provide a way to establish the relative age of scarps using the relationship between scarp height and scarp slope angle. This approach has been used for the last 25 years to conduct regional analyses on different fault scarps across seismically active regions to try to determine the paleoactivily of these regions. This approach has not been applied to fault scarp populations along a single fault zone with high-resolution laser data. With the high resolution topographic data we can collect hundreds of scarp profiles and from this create very dense plots with a lot of data. Using this approach on a populations of scarps along a given fault zone we can distinguish scarps with differing apparent ages based on where they plot in scarp height - slope angle space. If the scarps all plot in the same linear data cloud then we surmise that they have effectively the same apparent age and likely all formed in a single event. If on the other hand the data from different scarps plot in statistically distinct linear data clouds then we surmise that these scarps were either formed in different events or that they formed in the same event but are degrading at different rates. This is important information because it first gives us information regarding the way in which seismicity is released along particular faults and it also gives us information about differential fault scarp degradation. So, if we couple the high resolution fault scarp analyses with dating techniques that will allow us to accurately date scarps then we will start to be able to evaluate the importance of differential degradation as well as intermediate seismicity patterns. This research project has helped to lay the critical foundation for this new line of research into fault scarps and intermediate term seismic behavior and was therefore a general success.
Projektbezogene Publikationen (Auswahl)
-
Role of Erosion on Closely-Spaced Fault Scarps: High-resolution Laser Scanning Data and Scarp Diffusion Modelling of the Rex Hills Flower Structure, Nevada: - Eos Trans. AGU, 88(52), Fall Meet. Suppl., Abstract T51C- 0695
Baran, R., B. Guest, AM Friedrich
-
Dead or just resting? Geodetic versus geologic slip rates: Pahrump segment of the Stateline fault system, California-Nevada, USA. Abstracts with programs, 2007 GSA Denver Annual Meeting (28-31 October 2007) Paper No. 163-9
Hoffmann, Markus , Kuebler, Simon, and Guest, Bernard
-
Fault slip rates in time and space along the eastern margin of the Eastern California shear zone: Stateline fault system, California-Nevada, USA. Geophysical Research Abstracts, Vol. 10, EGU2008-A- 10795, 2008 SRef-ID; 1607-7962/gra/EGU2008-A-l0795, EGU General Assembly 2008
Guest, Bernard, Kuebler, Simon, and Hoffmann, Markus
-
The surface expression of a multiphase flower structure: A ground-based LIDAR case study in the southern Amargosa desert, Nevada. Geological Society of America Bulletin
Baran, R., Guest, B., Friedrich A.M.
