Regional Resource Area Mapping in Nevada Using the USArray Seismic Network

Abstract

The Earthscope Transportable Array (TA) seismic network is a significant new development for regional seismic velocity modeling and potential geothermal resource development. While very sparse compared to exploration scale applications, this network nevertheless affords regional modelers with unprecedented resolution and uniformity of coverage. The network is funded by the National Science Foundation through a major earth sciences initiative called Earthscope (www.earthscope.org). The network is presently in Nevada and the Great Basin, so data are accumulating from which regional velocity models can be constructed. Regional velocity models contribute to geothermal resource assessment in the Great Basin because seismic properties in the crust and shallow mantle correlate with geothermally consequential parameters such as rock temperature, composition and structure. In this paper we provide a first assessment of the actual ray coverage available for modeling structure in Nevada and the adjoining Great Basin and evaluate it in terms of prospects for resolution of crustal features and properties. While it is a work in progress, body-wave ray coverage should be sufficient for resolution of the crust and Moho at a scale of 10 km or better for the central portion of the region. Ray coverage and likely resolution from surface-wave studies is somewhat less because of signal-to-noise competition with naturally occurring background sources.