Surface Wave Data
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Figure 3
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[11] As mentioned above, additional observational data are required
to stabilize the receiver function inversion results. Phase
velocities of surface waves have recently been utilized for this purpose
[Julia et al., 2000].
Such data are unavailable from RUKSA records due to the overly small aperture.
However, the phase velocities were determined from SVEKALAPKO (without RUKSA)
broadband records of many earthquakes
[Bruneton et al., 2004].
The method consists in the measurement
of traveltimes of the Rayleigh wave fundamental mode between
their curvilinear fronts within the SVEKALAPKO array and
the inversion of the measured data into the phase velocity field.
These data in the form of dispersion curves of the Rayleigh phase
velocity at grid nodes covering the SVEKALAPKO array were afforded
by M. Bruneton, who used them for the construction of the SVEKALAPKO
tomography model
[Bruneton et al., 2004].
A phase velocity curve in the range of periods from 10.5 s to 190 s
was constructed at each grid point. We used the dispersion curve that
was obtained by extrapolating the set of these curves (Figure 3) to
the point with the RUKSA coordinates by the kriging method
[Isaacs and Srivastava, 1989].
In our opinion, this procedure is reliable because the spread
of the dispersion curves in the region about 500 km across is small
(Figure 3) and the distance from the RUKSA array to the nearest
SVEKALAPKO stations does not exceed 100 km. The inversion interval
of periods was 10.5-110 s.
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