Abstract

Effects of a basin structure on long period ground motion generation in Eskişehir region are studied by investigating the observed features of the 2011 Simav Earthquake (Mw:5.9) accelerograms. Spectral values and significant duration of ground motion at the basin center is much higher than the predicted mean values obtained by empirical models. 3-D wave propagation simulation of a small magnitude local event is accomplished utilizing a finite difference method and experimental velocity models. Simulation results indicate that the basin model produces more realistic waveforms than the flat layered model. Synthetic velocities agree with observed ones at two basin-center stations but considerable discrepancies exit at basin edge stations. These findings suggest that more careful definitions of basin boundaries are necessary for future models.

References

[1] Gülerce, Z., B. Kargoığlu and N. A. Abrahamson. Turkey-adjusted NGA-W1 horizontal ground motion prediction models. Earthquake Spectra 2016;32;75-100.

[2] Kale, Ö., S. Akkar, A. Ansari and H. Hamzehloo. A ground-motion predictive model for Iran and Turkey for horizontal PGA, PGV, and 5% damped response spectrum: Investigation of possible regional effects. Bulletin of the Seismological Society of America 2015;105;963-980.

[3] Sandıkkaya, M. A. and S. Akkar. Cumulative absolute velocity, Arias intensity and significant duration predictive models from a pan-European strong-motion dataset. Bulletin of Earthquake Engineering 2017;15;1881-1898.

[4] Mindevalli, O. Y. and B. J. Mitchell. Crustal structure and possible anisotropy in Turkey from seismic surface wave dispersion. Geophysical Journal International 1972; 98;93-106.

[5] Özel, O., E. Yalcinkaya, G. Birgoren, M. Tün, E. Pekkan, O. Kaplan. Kabuk depremleri nedeniyle oluşan Kuvvetli yer hareketinin tahmini için jeolojik yapıların modellemesi ortak araştırması. 2020; TUBITAK 1001 Project, Projct Code: 116Y524.

[6] Tün, M., E. Pekkan, O. Özel and Y. Guney. An investigation into the bedrock depth in the Eskisehir Quaternary Basin (Turkey) using the microtremor method. Geophysical Journal International 2016;207;589-607.

[7] Yamanaka, H., Ö. T. Özmen, K. Chimoto, M. A. Alkan, M. Tün, E. Pekkan, O. Özel, D. Polat and M. Nurlu. Exploration of S-wave velocity profiles at strong motion stations in Eskisehir, Turkey, using microtremor phase velocity and S-wave amplification”, Journal of Seismology. 2018;22;1127-1137.

[8] Pitarka, A. 3D elastic finite-difference modeling of seismic motion using staggered grids with nonuniform spacing”, Bulletin of the Seismological Society of America. 1999;89;54-68