Measurements of stress parameter and site attenuation from recordings of moderate to large earthquakes in Europe and the Middle East

作者：Edwards Ben^*; Faeh Donat

来源：Geophysical Journal International, 2013, 194(2): 1190-1202.

DOI：10.1093/gji/ggt158

• Time-series analysis
• Fourier analysis
• Earthquake ground motions
• Earthquake source observations
• Seismic attenuation
• Site effects

We analyse the raw, unfiltered acceleration time-series strong-motion data used for the European Strong Motion Database. After selecting high-quality recordings, suitable for Fourier analysis, we estimate crustal and site attenuation properties, Q(0) and kappa(0), respectively, using two methods: a broad-band spectral modelling approach and a high-frequency linear fit. We find kappa(0) varies strongly, from negligible to kappa(0) = 0.09 s, with an average of kappa(0) = 0.032 s or kappa(0) = 0.033 s depending on the method employed. This is consistent with the wide variety of recording-site conditions from hard-rock to very-soft soil. Using the attenuation model, we then proceed to determine site-class amplification, seismic moments and omega(2) stress parameters for several events with M-w values between 5 and 7.6. Site amplification is shown to vary strongly within a single site-class, although average amplification is consistent with resonance expected at soft-soil sites and theoretical crustal amplification at hard-rock sites. We show that seismic moments determined from Fourier spectra are consistent with database M-w values from moment tensor analysis, and that the resulting stress parameters are independent of magnitude or depth. Finally, we show that using the results of our analyses, along with the R-eff distance metric to account for the geometry of the finite fault, we can predict pseudospectral acceleration (peak ground acceleration to 10 s) of the Izmit 1999 (M-w 7.5-7.6) event using a point-source stochastic simulation.

• 出版日期2013-8