On measuring surface wave phase velocity from station-station cross-correlation of ambient signal
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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
Originalsprog | Engelsk |
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Tidsskrift | Geophysical Journal International |
Vol/bind | 192 |
Udgave nummer | 1 |
Sider (fra-til) | 346-358 |
Antal sider | 13 |
ISSN | 0956-540X |
DOI | |
Status | Udgivet - 26 mar. 2013 |
Eksternt udgivet | Ja |
ID: 188757187