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Ambient-field Green's functions from asynchronous seismic observations

Shuo Ma, & Gregory C. Beroza

Published March 2012, SCEC Contribution #1538

We demonstrate that the coda of station-to-station Green’s functions extracted from the ambient seismic field in southern California reach stability in the microseism band (5 – 10 s) after correlating six months of noise data. The coda stability makes it possible to retrieve Green’s functions between stations that operate asynchronously through scattered waves as recorded by a network of fiducial stations. The Green’s functions extracted from asynchronous and synchronous data have nearly identical quality as long as stable virtual coda are used, both showing good convergence to the Green’s function extracted from 1 year of seismic noise with ~50 fiducial stations. This approach suggests that Green’s functions can be extracted across seismic stations occupied regardless of whether or not they are occupied simultaneously. A new mode for seismic experiments that seek to constrain Earth structure can be designed.

Ma, S., & Beroza, G. C. (2012). Ambient-field Green's functions from asynchronous seismic observations. Geophysical Research Letters, 39(6), L06301. doi: 10.1029/2011GL050755.