SCEC Award Number 11160 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Extraction of Station-to-Station Green's Functions Using Seismic Coda in Southern California
Investigator(s)
Name Organization
Shuo Ma San Diego State University
Other Participants Evan Hirakawa
SCEC Priorities B4, C, B5 SCEC Groups Seismology, USR, GMP
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
 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 comparable quality as long as stable virtual coda are used, and both show good convergence to the Green’s functions extracted from 1 year of seismic noise with ~50 fiducial stations. This approach suggests that Green’s functions can be extracted across seismic stations regardless of whether or not they are occupied simultaneously, which raises the prospect of a new mode for seismic experiments that seek to constrain Earth structure.
Intellectual Merit We demonstrate that it is possible to extract station-to-station Green's functions between networks that operate at different times. The asynchronous Green's functions can greatly increase the number of path paths that contain important constraints for the Earth structure.
Broader Impacts Our approach suggests a new mode for seismic observations and may affect future experiment design.
Exemplary Figure Figure 5. Conceptual diagram of a new approach to observational seismology showing possibility of linking all stations occupied at all times with asynchronous Green’s functions through a backbone, or fiducial, seismic network. The networks occupied at different times are equivalent to occupy simultaneously. Measurements, shown schematically in green, between two temporary networks shown in black and blue, could be made through our approach.