Simulation of strong ground motion on near-fault rock outcrop for engineering purposes: the case of the city of Xanthi (northern Greece)

Abstract

We combine probabilistic and deterministic approaches in an attempt to tackle a challenging topic in engineering seismology, that of the prediction of strong ground motion in urban areas located close to active faults, with sparse modern seismicity. The case we study is the city of Xanthi in northern Greece and we generate bedrock synthetic time series to be used as input motions into site-specific site effect analysis. We re-assess the seismic hazard using the probabilistic method and then perform hazard deaggregation in order to define realistic earthquake scenarios, which we examine in a deterministic way. The scenarios examined are: (a) a reference earthquake of M6.7, return period 100 years and at *30 km distance from the city and (b) a reference earthquake of M5.8, return period 475 years and at *3 km distance from the city of Xanthi. To compute synthetic time series for the distant source, we apply the stochastic method for finite faults. For the near-fault earthquake scenario we adopt a hybrid deterministic-stochastic approach that includes the semi-analytical method implemented in the COMPSYN code for the low frequency (*\3 Hz) part of the spectrum and the stochastic method for the high-frequency (*[3 Hz). The results of the probabilistic and the deterministic approaches converge to a satisfactory degree.

Application of a Hybrid Modeling Method for Generating Synthetic Ground Motions in Fennoscandia, Northern Europe

“…The earthquakes investigated using COMPSYN include simulating the low-frequency ground-motions (≤1 Hz) of the 2011 Lorca Mw5.2 event in Spain (Moratto et al, 2017), the 2009 L'Aquila Mw6.1 event in Italy (Cirella et al, 2012), the 2003 Bam Mw6.3 event in Iran (Nickman and Eslamian, 2010), and the 2000 Western Tottori Mw6.7 event in Japan (Monelli and Mai, 2008). Roumelioti et al (2017) and Ameri et al (2008) used COMPSYN to simulate the low-frequency content of ground motions of the potentially dangerous faults near Xanthi and Thessaloniki in northern Greece, respectively. Fälth et al (2015) benchmarked synthetic ground motions computed in 3DEC with COMPSYN to confir m the compatibility of the two software tools for wave propagation.…”

“…The COMPSYN program has mainly been limited to the simulation of low frequencies. The highfrequency content of synthetic ground motions was computed with stochastic models (Ameri et al , 2008;Nickman and Eslamian, 2010;Roumelioti et al, 2017), or with Empirical Green Functions (Moratto et al, 2017). The arguments for not using COMPSYN for the high-frequency content of synthetic ground motions were its inefficiency above 3 Hz (Nickman and Eslamian, 2010) and the computational cost of the Green's functions (Mai and Beroza, 2003).…”

Semi-automated stochastic simultaneous simulation of macroseismic information and strong ground motion records for recent strong earthquakes of the Aegean area

“…For the geometric attenuation the default geometric spreading was applied, which has been also shown to be appropriate for Greece [e.g. Roumelioti, 2004;Roumelioti et al, 2017;Kkallas et al, 2018;Giannaraki et al, 2019]. Moreover, the anelastic attenuation was constrained by a mean frequency-dependent quality factor, Q(f) = 100f 0.8 , proposed for the broader Aegean Sea by Hatzidimitriou (1993Hatzidimitriou ( , 1995.…”

Quantitative Identification of Pulse‐Like Ground Motions Based on Hilbert–Huang Transform

“…By analyzing the ground motions of the Nepal Mw7.8 earthquake, it was found that the energy of the velocity pulse is concentrated in a short period range of 4-8 s [29]. When analyzing the ground motion, Roumelioti considered that the signal with a frequency below 3 Hz is a low-frequency signal and higher than 3 Hz is a high-frequency one [30]. Based on the above research, it can be found that the determination of frequency threshold is very complex.…”