TY - JOUR
T1 - On measuring surface wave phase velocity from station-station cross-correlation of ambient signal
AU - Boschi, Lapo
AU - Weemstra, Cornelis
AU - Verbeke, Julie
AU - Ekström, Göran
AU - Zunino, Andrea
AU - Giardini, Domenico
PY - 2013
Y1 - 2013
N2 - We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one method involves the time-domain cross-correlation of signal recorded at different stations; the other is based on frequency-domain cross-correlation, and requires finding the zero-crossings of the real part of the cross-correlation spectrum. Furthermore, the time-domain method, as implemented here and in the literature, practically involves the important approximation that interstation distance be large compared to seismic wavelength. In both cases, cross-correlations are ensemble-averaged over a relatively long period of time (1 yr). We verify that the two algorithms give consistent results, and infer that phase velocity can be successfully measured through ensemble-averaging of seismic ambient noise, further validating earlier studies that had followed either approach. The description of our experiment and its results is accompanied by a detailed though simplifed derivation of ambient-noise theory, writing out explicitly the relationships between the surface wave Green's function, ambient-noise cross-correlation and phase and group velocities
AB - We apply two different algorithms to measure surface wave phase velocity, as a function of frequency, from seismic ambient noise recorded at pairs of stations from a large European network. The two methods are based on consistent theoretical formulations, but differ in the implementation: one method involves the time-domain cross-correlation of signal recorded at different stations; the other is based on frequency-domain cross-correlation, and requires finding the zero-crossings of the real part of the cross-correlation spectrum. Furthermore, the time-domain method, as implemented here and in the literature, practically involves the important approximation that interstation distance be large compared to seismic wavelength. In both cases, cross-correlations are ensemble-averaged over a relatively long period of time (1 yr). We verify that the two algorithms give consistent results, and infer that phase velocity can be successfully measured through ensemble-averaging of seismic ambient noise, further validating earlier studies that had followed either approach. The description of our experiment and its results is accompanied by a detailed though simplifed derivation of ambient-noise theory, writing out explicitly the relationships between the surface wave Green's function, ambient-noise cross-correlation and phase and group velocities
KW - Crustal structure
KW - Interferometry
KW - Seismic tomography
KW - Theoretical seismology
KW - Time-series analysis
UR - http://www.scopus.com/inward/record.url?scp=84875257919&partnerID=8YFLogxK
U2 - 10.1093/gji/ggs023
DO - 10.1093/gji/ggs023
M3 - Article
AN - SCOPUS:84875257919
SN - 0956-540X
VL - 192
SP - 346
EP - 358
JO - Geophysical Journal International
JF - Geophysical Journal International
IS - 1
ER -