INTEGRATED SEISMIC MICROZONATION FOR URBAN RESILIENCE: THE CASE OF ESKISEHIR CITY CENTER

Abstract

Enhancing urban resilience in seismically active regions is essential for reducing disaster risks and ensuring sustainable development. This study characterizes the dynamic engineering parameters of soils in Eskisehir’s city center, a region situated in Central Anatolia that faces high seismic risk due to its young alluvial deposits and proximity to active faults. To achieve this, detailed geophysical surveys were conducted using seismic refraction and microtremor (HVSR) methods at selected locations, and the resulting data were analyzed using Geographic Information Systems (GIS). The findings reveal significant spatial heterogeneity in soil behavior within the upper 30 meters. Specifically, Vs₃₀ values across the study area were found to range from 145 to 990 m/s, with low-velocity zones (145–315 m/s) heavily concentrated in densely populated districts. Consequently, the GIS-based Site Amplification (Fa) maps exhibited values ranging from 0.92 to 1.70, pinpointing specific zones with high seismic amplification potential. Furthermore, while fundamental site periods varied between 0.09–2.86 s, a critical concentration of periods in the 0.43–0.85 s range was identified. This range directly corresponds to the natural vibration periods of 4-8 story reinforced concrete buildings, indicating a high potential for destructive soil-structure resonance. These quantitative results provide an operational basis for multi-level planning processes specifically for defining priority zones in urban transformation and enforcing height restrictions in land-use decision-making thereby demonstrating the strategic role of geophysical methods in multidisciplinary disaster management.

Keywords

• Urban Resilience
• Seismic Microzonation
• Vs30
• Site Amplification
• GIS

INTEGRATED SEISMIC MICROZONATION FOR URBAN RESILIENCE: THE CASE OF ESKISEHIR CITY CENTER

Abstract

IEnhancing urban resilience in seismically active regions is essential for reducing disaster risks and ensuring sustainable development. This study characterizes the dynamic engineering parameters of soils in Eskisehir’s city center, a region situated in Central Anatolia that faces high seismic risk due to its young alluvial deposits and proximity to active faults. To achieve this, detailed geophysical surveys were conducted using seismic refraction and microtremor (HVSR) methods at selected locations, and the resulting data were analyzed using Geographic Information Systems (GIS). The findings reveal significant spatial heterogeneity in soil behavior within the upper 30 meters. Specifically, Vs₃₀ values across the study area were found to range from 145 to 990 m/s, with low-velocity zones (145–315 m/s) heavily concentrated in densely populated districts. Consequently, the GIS-based Site Amplification (Fa) maps exhibited values ranging from 0.92 to 1.70, pinpointing specific zones with high seismic amplification potential. Furthermore, while fundamental site periods varied between 0.09–2.86 s, a critical concentration of periods in the 0.43–0.85 s range was identified. This range directly corresponds to the natural vibration periods of 4-8 story reinforced concrete buildings, indicating a high potential for destructive soil-structure resonance. These quantitative results provide an operational basis for multi-level planning processes specifically for defining priority zones in urban transformation and enforcing height restrictions in land-use decision-making thereby demonstrating the strategic role of geophysical methods in multidisciplinary disaster management.

Keywords

• Urban Resilience
• Seismic Microzonation
• Vs30
• Site Amplification
• GIS

References

1. [1] Li X, Liu Y, Zhang W, Wang Y. Research on an evaluation model of urban seismic resilience based on system dynamics: a case study of Chengdu, China. Sustainability 2023; 15(13): 10112. https://doi.org/10.3390/su151310112
2. [2] Zhao Y, Yang X, Zhai C, Wen W. Exploring relationships of urban seismic resilience assessment indicators with a fuzzy total interpretive structural model method. Eng Constr Archit Manag 2022; 30(8): 3509–3538. https://doi.org/10.1108/ECAM-07-2021-0663
3. [3] Díaz-García G. Application of MASW, microtremor, and seismic refraction tests for buildings in vulnerable communities. Buildings 2025; 15(7): 1079. https://doi.org/10.3390/buildings15071079
4. [4] Giallini S, Simionato M, Davani F, Gaudiosi I, Mancini M, Mendicelli A, et al. Integrated geophysical methodology for subsurface modeling and seismic response analysis in the Campi Flegrei area. EGU Gen Assem Conf Abstr 2025.
5. [5] Mendecki M, Glazer M, Mycka M. Application of passive seismic to shallow geological structures in urban areas. Stud Quat 2014; 31(2): 115–122. https://doi.org/10.2478/squa-2014-0011
6. [6] Adly A, Poggi V, Fäh D, Hassoup A, Omran A. Combining active and passive seismic methods for the characterization of urban sites in Cairo, Egypt. Geophys J Int 2017; 210(1): 428–442. https://doi.org/10.1093/gji/ggx168
7. [7] Bignardi S, Mantovani A, Abu Zeid N. OpenHVSR—Processing toolkit: enhanced HVSR processing of microtremor data and 2D/3D visualization. Comput Geosci 2018; 120: 10–20. https://doi.org/10.1016/j.cageo.2018.07.006
8. [8] Hunter JA, Crow HL, Stephenson WJ, Pugin AJM, Williams RA, Harris JB, Odum JK, Woolery EW. Seismic site characterization with shear-wave (SH) reflection and refraction methods. J Seismol 2022; 26(4): 631–652. https://doi.org/10.1007/s10950-022-10082-6

9. [9] Molnar S, Sirohey A, Assaf J, Bard P-Y, Castellaro S, Cornou C, Cox B, et al. A review of the microtremor horizontal-to-vertical spectral ratio (MHVSR) method. J Seismol 2022; 26(4): 653–685. https://doi.org/10.1007/s10950-021-10062-9
10. [10] Perton M, Spica Z, Caudron C. Inversion of the horizontal-to-vertical spectral ratio in presence of strong lateral heterogeneity. Geophys J Int 2018; 212(2): 930–941. https://doi.org/10.1093/gji/ggx447
11. [11] Stephenson WJ, Yong A, Martin AJ, Williams RA, et al. Flexible multimethod approach for seismic site characterization. J Seismol 2022; 26: 1–25. https://doi.org/10.1007/s10950-022-10103-4
12. [12] Van Ginkel J, Ruigrok E, Herber R. Using horizontal-to-vertical spectral ratios to construct shear-wave velocity profiles. Solid Earth 2020; 11: 2015–2030. https://doi.org/10.5194/se-11-2015-2020
13. [13] Farazi AH, Noguchi S, Torii Y, Obara K. Shear-wave velocity structure at the Fukushima forearc region using ambient seismic noise. Geophys J Int 2023; 233(3): 1801–1822. https://doi.org/10.1093/gji/ggad046
14. [14] Gosar A. Study on the applicability of the microtremor HVSR method to support seismic microzonation in the town of Idrija (W Slovenia). Nat Hazards Earth Syst Sci 2017; 17: 925–937. https://doi.org/10.5194/nhess-17-925-2017
15. [15] Mendicelli A, Moscatelli M, Peronace E, Naso G, Romagnoli G. Seismic amplification factors and national-scale mapping from the Italian seismic microzonation dataset. Georisk 2022; 16(4): 302–321. https://doi.org/10.1080/17499518.2021.1965158
16. [16] Mori F, Mendicelli A, Moscatelli M, Romagnoli G, Peronace E, Naso G. A new Vs30 map for Italy based on the seismic microzonation dataset. Eng Geol 2020; 275: 105745. https://doi.org/10.1016/j.enggeo.2020.105745
17. [17] Rosset P, Locat J, Lamontagne M. Vs30 mapping of the Greater Montreal Region using multiple data sources. Geosci 2023; 13(9): 256. https://doi.org/10.3390/geosciences13090256
18. [18] Khadrouf I, Boutaleb S, Moustadraf S. Contribution of HVSR, MASW and geotechnical investigations in seismic microzonation for safe urban extension: Ghabt Admin (Agadir, Morocco). J Afr Earth Sci 2024; 210: 105138. https://doi.org/10.1016/j.jafrearsci.2023.105138
19. [19] Molua C, Vwavware J, Chukwunwike O. Seismic hazard assessments for Nigeria’s urban centers. Earth Sci Pak 2024; 8(1): 19–27. https://doi.org/10.26480/esp.01.2024.19.27
20. [20] Firoozi A, Firoozi A. Geotechnical innovations for seismic-resistant urban infrastructure. J Civ Eng Urban 2024; 14(3s): 346–355. https://doi.org/10.54203/jceu.2024.7
21. [21] Pekkan E, Tün M, Güney Y, Mutlu S. Integrated seismic risk analysis using simple weighting method: The case of residential Eskişehir, Turkey. Nat Hazards Earth Syst Sci 2015; 15(5): 1123–1133. https://doi.org/10.5194/nhess-15-1123-2015
22. [22] Tosun H, Seyrek E, Orhan A, Savaş H, Türköz M. Soil liquefaction potential in Eskişehir, NW Turkey. Nat Hazards Earth Syst Sci 2011; 11(4): 1071–1082. https://doi.org/10.5194/nhess-11-1071-2011
23. [23] Orhan A, Seyrek E, Tosun H. A probabilistic approach for earthquake hazard assessment of the Province of Eskişehir, Turkey. Nat Hazards Earth Syst Sci 2007; 7(5): 607–614. https://doi.org/10.5194/nhess-7-607-2007
24. [24] Orhan A, Türköz M, Tosun H. Preliminary hazard assessment and site characterization of Meşelik campus area, Eskişehir, Turkey. Nat Hazards Earth Syst Sci 2013; 13(1): 75–84. https://doi.org/10.5194/nhess-13-75-2013
25. [25] Tün M, Pekkan E, Özel O, Güney Y. An investigation into the bedrock depth in the Eskişehir Quaternary Basin (Turkey) using the microtremor method. Geophys J Int 2016; 207(1): 589–607. https://doi.org/10.1093/gji/ggw297
26. [26] Tün M, Pekkan E, Mutlu S. The depth of alluvial sediments and subsurface profiling along the Eskişehir Basin in Central Turkey using microtremor observations. Bull Eng Geol Environ 2022; 81: 169. https://doi.org/10.1007/s10064-022-02667-w
27. [27] Yamanaka H, Özmen ÖT, Chimoto K, Alkan MA, Tün M, Pekkan E, Özel O, Polat D, Nurlu M. Exploration of S-wave velocity profiles at strong motion stations in Eskişehir, Turkey, using microtremor phase velocity and S-wave amplification. J Seismol 2018; 22(4): 1127–1137. https://doi.org/10.1007/s10950-018-9755-9
28. [28] Tün M, Ayday C. Investigation of correlations between shear wave velocities and CPT data: a case study at Eskişehir in Turkey. Bull Eng Geol Environ 2018; 77(1): 225–236. https://doi.org/10.1007/s10064-016-0973-2
29. [29] Orhan A, Tosun H. Visualization of geotechnical data by means of geographic information system: a case study in Eskişehir city (NW Turkey). Environ Earth Sci 2010; 61(3): 455–465. https://doi.org/10.1007/s12665-009-0357-1
30. [30] Tün M, Mutlu S, Pekkan E. EstuNet: A new weak/strong ground motion network for Eskişehir and Bursa metropolitan areas, Western Anatolia, Turkey. Turk Deprem Arastirma Derg 2020; 2(2): 193–208. (article in Turkish). https://doi.org/10.46464/tdad.739768
31. [31] Arslan MS, Özel AO. Seismic analysis and depth profile studies using H/V and SPAC methods in Eskişehir Basin. Gumushane Univ J Sci 2024; 14(3): 883–909. (article in Turkish with an abstract in English). https://doi.org/10.17714/gumusfenbil.1367098
32. [32] Fiorucci M, Martino S, Antonielli B, Charalampopoulou V, Ciampi P. Local seismic response in the historical centre of Nafplio (Greece) as a tool for seismic risk management. Natural Hazards 2025; 121(13): 15581-15611.
33. [33] Chu J, Zhang Q, Ai W, Yu H. A hybrid intelligent model for urban seismic risk assessment based on particle swarm optimization. Sci Program 2021; 1–16. https://doi.org/10.1155/2021/6652618
34. [34] Tokay F, Altunel E. Neotectonic activity of the Eskişehir Fault Zone in the vicinity of the İnönü–Dodurga area. Bull Miner Res Explor 2005; 130: 1–15.
35. [35] Altunel E, Barka AA. Neotectonic activity of the Eskişehir Fault Zone between İnönü and Sultandere. Turk Geol Bull 1998; 41(2): 41–52.
36. [36] Seyitoğlu G, Ecevitoğlu B, Kaypak B, Güney Y, Tün M, Esat K, Avdan U, Temel A, Çabuk A, Telsiz S, Aldaş GG. Determining the main strand of the Eskişehir strike-slip fault zone using subsidiary structures and seismicity: a hypothesis tested by seismic reflection studies. Turk J Earth Sci 2015; 24(1): 1–20. https://doi.org/10.3906/yer-1406-3
37. [37] Gözler MZ, Cevher F, Ergül E, Asutay HJ. Geology of central and southern Sakarya region. MTA Rep 1996; 9973: 87. (article in Turkish).
38. [38] Gözler MZ, Cevher F, Küçükyaman A. Geology and hot water sources of the Eskişehir region. MTA Derg 1985; 103: 40–54. (article in Turkish).
39. [39] Tosun H, Orhan A. Use of geographic information system software in determining the geo-engineering properties of foundation soils: The case of Eskişehir. ESOGU Muh Mim Fak Derg 2007; 20(2): 43–64. (article in Turkish).
40. [40] Güney Y, Ecevitoğlu B, Pekkan E, Avdan U, Tün M, Kaplan O, Mutlu S, Akdeniz E. Development of a geotechnical, structural, and geophysical information system for the Eskişehir settlement area using GIS techniques [Research project report]. Anadolu University Scientific Research Project; 2013.
41. [41] Emre Ö, Duman TY, Özalp S, Elmacı H, Olgun Ş, Şaroğlu F. Active fault map of Turkey at 1:1,125,000 scale [Special publication]. General Directorate of Mineral Research and Exploration (MTA); Ankara, Turkey; 2013.
42. [42] Orhan A. Geoengineering properties of foundation soil units and the application of geographic information system in the southern part of Eskişehir city center. PhD thesis, Eskişehir Osmangazi University, Eskişehir, Turkey; 2005.
43. [43] Konak N, Bakırcıhan B, Bedi Y, Dönmez M, Pehlivan Ş, Sevin M, Türkeşcan A, Yusufoğlu H. 1:1,000,000 scale geological map of Turkey [Map]. General Directorate of Mineral Research and Exploration (MTA); Ankara, Turkey; 2016.
44. [44] Karslı H, Babacan A, Şenkaya M, Gelişli K. Evaluation of rock detachability using P- and S-wave velocities and geological units. Pamukkale Univ Muh Bil Derg 2021; 27(3): 410–419. https://doi.org/10.5505/pajes.2020.66986
45. [45] Sarı A. Comparison of seismic methods in determining the dynamic properties of soils. Insaat Muh Derg 2022; 28(1): 67–79. https://doi.org/10.18400/imo.1036859
46. [46] Çakıcı Z. Use of seismic refraction method in determining elastic parameters of soils. Jeofizik Derg 2018; 22(3): 45–58. (article in Turkish).
47. [47] Nakamura Y. A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Quart Rep Railway Tech Res Inst 1989; 30(1): 25–33.
48. [48] OYO Corporation, Geometrics Inc. SeisImager/SWTM Manual; 2006.
49. [49] Wathelet M. An improved neighborhood algorithm: parameter conditions and dynamic scaling. Geophys Res Lett 2008; 35(9): L09301. https://doi.org/10.1029/2008GL033256
50. [50] Konno K, Ohmachi T. Ground-motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor. Bull Seismol Soc Am 1998; 88(1): 228–241. https://doi.org/10.1785/BSSA0880010228
51. [51] Borcherdt RD. Estimates of site-dependent response spectra for design. Earthq Spectra 1994; 10(4): 617–653. https://doi.org/10.1193/1.1585791
52. [52] Borcherdt RD. Empirical evidence for site coefficients in building code provisions. Earthq Spectra 2002; 18(2): 189–217. https://doi.org/10.1193/1.1486243
53. [53] Abrahamson N, Silva W. Summary of the Abrahamson & Silva NGA ground-motion relations. Earthq Spectra 2008; 24(1): 67–97. https://doi.org/10.1193/1.2924360
54. [54] Bindi D, Pacor F, Luzi L, Puglia R, Massa M, Ameri G, Paolucci R. Ground motion prediction equations derived from the Italian strong motion database. Bull Earthquake Eng 2011; 9(6): 1899–1920. https://doi.org/10.1007/s10518-011-9313-z
55. [55] Joyner WB, Fumal TE. Use of measured shear-wave velocity for predicting geologic site effects. Proc 8th World Conf Earthquake Eng; 1984; San Francisco. Vol 2: 777–783.
56. [56] FEMA. NEHRP recommended provisions for seismic regulations for new buildings and other structures (FEMA 368). Federal Emergency Management Agency, Washington, DC, USA; 2000.
57. [57] Chopra AK, Goel RK. Building period formulas for estimating seismic displacements. Earthq Spectra 2000; 16(2): 533–536. https://doi.org/10.1193/1.1586125
58. [58] Crowley H, Pinho R. Simplified equations for estimating the period of vibration of existing buildings. Earthq Eng Struct Dyn 2006; 35(4): 525–544. https://doi.org/10.1002/eqe.555
59. [59] Velani H, Ramancharla PK. New empirical formula for fundamental period of reinforced concrete buildings in India. In: 16th World Conf Earthquake Eng; 2017.
60. [60] Mutlu S, Tün M, Pekkan E, Güney Y. Producing of engineering properties of soil maps of Eskişehir and determination of the ground amplification of city center. 4th Int Earthquake Eng Seismol Conf; 2017; Eskişehir. (article in Turkish).
61. [61] Çoban KH, Bayrak E. Determination of site fundamental frequency/period and H/V spectral ratio values using earthquake data: A case study of Eskişehir Province. Turk Deprem Arastirma Derg 2024; 6(1): 81–97. (article in Turkish with an abstract in English). https://doi.org/10.46464/tdad.1388909.