Shear wave structure of southern Sweden from precise phase-velocity measurements of ambient-noise data
| Autor: | Björn Lund, Karin Högdahl, Olafur Gudmundsson, Hamzeh Sadeghisorkhani, Ari Tryggvason, Ka Lok Li |
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| Rok vydání: | 2020 |
| Předmět: |
010504 meteorology & atmospheric sciences
Ambient noise level Seismic interferometry Seismic noise 010502 geochemistry & geophysics 01 natural sciences Geophysics Shear (geology) Geochemistry and Petrology Seismic tomography Wave structure Phase velocity Geology Seismology 0105 earth and related environmental sciences |
| Zdroj: | Geophysical Journal International. 225:494-511 |
| ISSN: | 1365-246X 0956-540X |
| DOI: | 10.1093/gji/ggaa598 |
| Popis: | SUMMARY Rayleigh-wave phase-velocity tomography of southern Sweden is presented using ambient seismic noise at 36 stations (630 station pairs) of the Swedish National Seismic Network. We analyse 1 yr (2012) of continuous recordings to get the first crustal image based on the ambient-noise method in the area. Time-domain cross-correlations of the vertical component between the stations are computed. Phase-velocity dispersion curves are measured in the frequency domain by matching zero crossings of the real spectra of cross-correlations to the zero crossings of the zeroth-order Bessel function of the first kind. We analyse the effect of uneven source distributions on the phase-velocity dispersion curves and correct for the estimated velocity bias before tomography. To estimate the azimuthal source distribution to determine the bias, we perform inversions of amplitudes of cross-correlation envelopes in a number of period ranges. Then, we invert the measured and bias-corrected dispersion curves for phase-velocity maps at periods between 3 and 30 s. In addition, we investigate the effects of phase-velocity bias corrections on the inverted tomographic maps. The difference between bias-corrected and -uncorrected phase-velocity maps is small ( |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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