Abstract
The seismic hazard in the İzmit basin, located in Marmara region of western Turkey, is high due to the northern branch of the North Anatolian Fault (NAF) and the potential ground motion amplification that may be caused by local site conditions, sedimentary basin effect as well as fault zone (FZ) induced site effect resulting from the generation of guided waves. In this study, we elaborate the relevance of the FZ-induced site effect in the İzmit basin along a 16.5-km-long N-S profile across the basin and perpendicular to the NAF by time and frequency domain analysis of waveforms obtained from two-dimensional (2D) simulations of viscoelastic wave propagation for a double-couple source at 14 km depth using a reference (basin-only) model and three basin-with-fault models: shallow (6 km), intermediate (12 km) and deep (19 km) FZ models. Our results show that the FZ-induced site effect within and near the northern branch of NAF in the İzmit basin can be very prominent with amplifications of about 5–10 in the frequency range of 0.05–4 Hz and about 20 at frequencies above 2 Hz, respectively. We obtain the most dramatic results for the deep FZ model causing shear- and surface-wave amplifications of about 15 at frequencies higher than 2.5 Hz for the distances between 6 and 13 km.
| Original language | English |
|---|---|
| Pages (from-to) | 2069-2083 |
| Number of pages | 15 |
| Journal | Acta Geophysica |
| Volume | 69 |
| Issue number | 6 |
| DOIs | |
| Publication status | Published - Dec 2021 |
Bibliographical note
Publisher Copyright:© 2021, Institute of Geophysics, Polish Academy of Sciences & Polish Academy of Sciences.
Funding
We would like to thank Prof. Hayrullah Karabulut for his support and constant feedback about this work. We also would like to thank Dr. Serdar Özalaybey and Dr. Ekrem Zor of the Institute of Earth and Marine Sciences, Marmara Research Center, Scientific and Technical Research Council of Turkey (TUBITAK) for sharing the shear-wave velocity structure and bedrock topography information of the İzmit basin we used in our modeling studies. Finally, we would like to thank Dr. Askan and one anonymous reviewer for their helpful comments and suggestions. This study was partially supported by the İstanbul Technical University Scientific Research Project, BAP 36240. We would like to thank Prof. Hayrullah Karabulut for his support and constant feedback about this work. We also would like to thank Dr. Serdar Özalaybey and Dr. Ekrem Zor of the Institute of Earth and Marine Sciences, Marmara Research Center, Scientific and Technical Research Council of Turkey (TUBITAK) for sharing the shear-wave velocity structure and bedrock topography information of the İzmit basin we used in our modeling studies. Finally, we would like to thank Dr. Askan and one anonymous reviewer for their helpful comments and suggestions. This study was partially supported by the İstanbul Technical University Scientific Research Project, BAP 36240.
| Funders | Funder number |
|---|---|
| Institute of Earth and Marine Sciences | |
| Marmara Research Center, Scientific and Technical Research Council of Turkey | |
| Türkiye Bilimsel ve Teknolojik Araştirma Kurumu | BAP 36240 |
Keywords
- Fault-zone induced waves
- Finite difference method
- Seismic wave propagation simulation
- Site amplification
- İzmit basin