Research
Tectonic Deformation of the Basin and Range Province
CSTARS is conducting a research project to precisely measure and better understand the deformation of the Basin and Range Province in the Western United States. The Basin and Range Province is located between the Sierra Nevada in the West and the Rocky Mountains in the East. For a long time it was thought that the Basin and Range Province with its alternating north-south trending Basins and Ranges is under uniform east-west extension. However, precise geodetic measurements using the Global Positioning System showed that deformation is not uniform but occurs mostly in the western part of the region.
In collaboration with the European Space Agency CSTARS is obtaining the Synthetic Aperture Radar imagery acquired by the ERS satellites between 1992 and 2004 (a total of 6000 scenes). Using the InSAR technique we will combine the SAR imagery to a very precise ground deformation map. This project is an effort to better understand the nature of the deformation of the Basin and Range province and the forces that drive it.
The figures shows the area of investigation and a preliminary ground velocity map for a SAR swath covering Central Nevada. The SAR swath covers the so-called Central Nevada Seismic Belt where a number of earthquakes with magnitude larger than 7 occurred in the first half of the past century. The ground velocity map shows that 2-3 mm/yr of ground deformation in direction towards the satellite is occurring between 1992 and 2004. We interpret the observed deformation as very slow, viscous flow of the rocks in the Earth’s crust and mantle induced by the earthquakes, a phenomenon known as post-seismic relaxation and commonly observed after last earthquakes.
This work is closely related to the Plate Boundary Observatory of Western North America (PBO, http://pbo.unavco.org/) , which is part of the National Science Foundation’s EarthScope initiative (http://www.earthscope.org). To precisely measure tectonic deformation the Plate Boundary Observatory is deploying about 800 permanent GPS receivers across the Western United States, 100 of which will be located in the Basin and Range. Contact: Noel Gourmelen (ngourmelen@rsmas.miami.edu ) and Falk Amelung (famelung@rsmas.miami.edu).
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