Attenuation tomography of the western United States from ambient seismic noise
We show that the spatial coherency of the ambient seismic field can be used for attenuation tomography in the western United States. We evaluate the real portion of the spatial coherency with an elastic geometric spreading term (a Bessel function) and a distance dependent decay (an attenuation coeff...
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Published in | Journal of Geophysical Research Vol. 116; no. B6 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Washington
Blackwell Publishing Ltd
01.06.2011
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Subjects | |
Online Access | Get full text |
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Summary: | We show that the spatial coherency of the ambient seismic field can be used for attenuation tomography in the western United States. We evaluate the real portion of the spatial coherency with an elastic geometric spreading term (a Bessel function) and a distance dependent decay (an attenuation coefficient). In order to invert the spatial coherency, a weight stack inversion technique is applied. We recover phase velocity and attenuation coefficient maps at periods of 8–32s, which correspond to the elastic and anelastic structure at crustal and upper mantle depths. The phase velocity maps obtained by this method are of similar resolution to more standard two‐station methods. The attenuation results provide an important complement to the information extracted from earthquake‐based tomography. Several geological features are easily identifiable in the attenuation coefficient maps, such as the highly attenuating sedimentary basins along the West Coast of the United States, and the highly attenuating Yellowstone region, and the boundaries of the Snake River Plains.
Key Points
Lateral variations in seismic attenuation can be obtained from ambient noise
Seismic attenuation structure is illuminated beneath the western United States
Empirical greens functions contain amplitude content for attenuation studies |
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Bibliography: | ark:/67375/WNG-2VW7QDCX-2 istex:7C1A008ED68351E6744E4D938820940666F47862 ArticleID:2010JB007836 |
ISSN: | 0148-0227 2169-9313 2156-2202 2169-9356 |
DOI: | 10.1029/2010JB007836 |