Calibration of the SCEC broadband platform for European Applications - The example of Germany -
Abstract
Over the last few decades, the development of advanced ground-motion simulation methodologies has attracted growing attention. Calibration and comprehensive validation of such approaches are necessary to ensure the reliability of simulations for engineering-use in a particular region. Having well-tested, reference ground-motion waveforms is particularly important to subsequently test various approaches for incorporating the influence of near-surface site response (e.g., VS30-based, site amplification from spectral decomposition analysis, and numerical simulation). This study aims to calibrate and test the Graves and Pitarka hybrid broadband method for applications in Germany. Our development includes four steps: 1) the calibration of the approach on rock condition, in which the parameters of the high-frequency simulations, including the attenuation model and stress parameters, are tuned according to the European spectral decomposition results; 2) Selection of rock stations displaying a flat H/V, similar spectral decay factor on the S-wave and the late coda window, and with Vs30>800m/s; 3) Testing of simulations using low-to-moderate magnitude earthquakes (3.7<Mw<5) that have occurred in Germany and the surrounding areas; and 4) The implementation of Fourier amplification models.
To assess the performance of the simulation for rock conditions, we use the standard approach in the SCEC platform (comparison of the waveforms, intensity measures, and estimation of the response-spectra model bias). We also compare the Fourier Amplitude Spectrum (FAS) of the simulation and observations (ESM, EIDA, and RAP datasets). Our results show that the simulated ground-motions match the general characteristics of the recorded motion and have a model bias generally fluctuates around zero across the broadband frequency range (0-10Hz). Since our site response contains only amplitude terms (without the phase), validation of the simulation for all sites was performed in the Fourier domain, where we made use of model bias for the FAS. In this case, two different amplification models were tested: Vs30-based (from empirically derived Fourier models) and inferred site amplification from spectral decomposition analysis. Our results demonstrate the potential benefits of using the site effects from spectral decomposition relative to Vs30-based amplification to represent the near-surface site effects.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S31C0527R
- Keywords:
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- 7209 Earthquake dynamics;
- SEISMOLOGY;
- 7212 Earthquake ground motions and engineering seismology;
- SEISMOLOGY;
- 7215 Earthquake source observations;
- SEISMOLOGY;
- 7290 Computational seismology;
- SEISMOLOGY