Article,
Passive seismic imaging with directive ambient noise: application to surface waves and the San Andreas Fault in Parkfield, CA
Geophysical Journal International, 179 (1): 367--373 (October 2009)
DOI: 10.1111/j.1365-246X.2009.04282.x
Abstract
This study deals with surface waves extracted from microseismic noise
in the (0.1-0.2 Hz) frequency band with passive seismic-correlation
techniques. For directive noise, we explore the concept of passive
seismic-noise tomography performed on three-component sensors from
a dense seismic network. From the nine-component correlation tensor,
a rotation algorithm is introduced that forces each station pair
to re-align in the noise direction, a necessary condition to extract
unbiased traveltime from passive seismic processing. After rotation
is performed, the new correlation tensor exhibits a surface wave
tensor from which Rayleigh and Love waves can be separately extracted
for tomography inversion. Methodological aspects are presented and
illustrated with group-speed maps for Rayleigh and Love waves and
ellipticity measurements made on the San Andreas Fault in the Parkfield
area, California, USA.
