Review of EarthScope Integrated Science (2001) / Chapter Skim
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2 Scientific Rationale and Science Questions
2 Scientific Rationale and Science Questions
Pages 21-32
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From page 21... ...
in the earth? If we can see how strain accumulates and know the properties of materials at depth in a fault zone, can we recognize signals that tell us that an earthquake is imminent?
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From page 22... ...
It has a long geologic history extending back in time over 3 billion years, and boasts a robust, active, superbly qualified earth science community and the world's most advanced electronic communication network. Because techniques are now being developed that will allow this earth science community to image the earth in unprecedented detail, the emerging challenge is to exploit the new imaging capabilities to develop as complete a picture as possible of the interior of our planet, its evolution, and its present-day deformation.
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From page 23... ...
The committee suggests that one of the key challenges of the EarthScope program will be to ensure that this integration of information, knowledge, and expertise occurs in the most effective way possible. In the remainder of this chapter, the committee presents comments concerning each of the science components of EarthScopethe United States Seismic Array, the Plate Boundary Observatory, the San Andreas Fault Observatory at Depth, the Interferometric Synthetic Aperture Radar mission—and the integrated EarthScope Education and Outreach Program.
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From page 24... ...
The committee notes that the EarthScope and USArray proponents had given much thought to how to deploy the transportable array, and to the geometry and sequence in which it rolls across the continent. The one-year deployment time and 70-kilometer spacing will necessarily place some limitations on the scale of observations that can be made with the transportable array, especially in regions with low natural seismicity.
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From page 25... ...
Many of these management concerns apply equally to the flexible component of the GPS networks that form part of the PBO. EarthScope Components: San Andreas Fault Observatory at Depth (SAFOD)
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From page 26... ...
The proposed facility will allow scientists to build on existing knowledge to address many fundamental questions about the physical and chemical processes acting within the San Andreas Fault and, by extension, to the faulting process in general. Drilling, sampling, and continuous measurements directly within the fault zone will test controversial scientific hypotheses about earthquakes by providing direct information on the composition and mechanical properties of active fault zone rocks, the nature of stresses ("normalized" force or force intensity)
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From page 27... ...
SAFOD will provide critical in situ data on physical and theological properties of earth materials at depth. USArray provides the tool for extrapolating the in situ data to a broader region and larger spatial scales.
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From page 28... ...
This should in turn facilitate the development of realistic dynamic models to help explain why these movements occur, and stimulate related scientific research that should lead to a reduction in risks associated with earthquakes, volcanic eruptions, and associated land movements such as landslides. Correlation of PBO observations with data from other EarthScope components will be invaluable.
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From page 29... ...
Since its first demonstration to map the surface displacements associated with the 1992 Landers earthquake, InSAR has produced some spectacular images of deformation associated with earthquakes and volcanoes, and has been used to investigate a wide range of phenomena: the slow accumulation of crustal strain across fault zones, the motions that occur immediately following an earthquake and that allow the mechanical properties of the crust and uppermost mantle to be investigated, the inflation or deflation of volcanoes due to movement of magma at depth (e.g., Figure 4) , subsidence in urban areas due to the extraction of oil or water, and the movement of Antarctic ice streams.
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From page 30... ...
The instrument deployments and experiments that will bring earth science to local communities across the nation are the key elements that will provide opportunities for development of educational materials that are particularly relevant on a regional basis. The committee strongly endorses the EarthScope Working Group's intention to include an extensive E&O effort in their project plan.
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From page 31... ...
In addition, education and outreach activities will benefit from the intention to make all EarthScope data freely and rapidly available—a policy the committee endorses wholeheartedly. EarthScope and its tools and techniques could furnish powerful data sets for future geoscientists.
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From page 32... ...
The committee strongly endorses all four scientific components of the EarthScope initiative and the education and outreach plans.
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