Spectral Ratio Estimates for Site Effects on the Horst–Graben System in West Turkey
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Recordings of micro- and moderate-size local earthquakes have been used to quantify site effects in the central-west Turkey which contains one of the world’s best examples of a rapid intra-continental extension with its high population and industrial potential. We analyzed 436 earthquakes with local magnitudes ranging between 2.0 and 5.6 using three component digital recordings from 32 stations. Site functions were obtained using two different spectral ratio approaches (horizontal to vertical spectral ratio, HVSR, and standard spectral ratio, SSR). HVSR estimates of transverse and radial S-waves were compared with one another. Epicentral distance, magnitude and back-azimuth dependencies of site functions were also evaluated. In general, HVSR values from transverse and radial S-waves are similar within a factor of 2. The back-azimuth dependencies of transverse S-wave HVSR results are more significant than distance and magnitude dependencies. On the other hand, averaging of transverse and radial S-wave HVSR results eliminates systematic back-azimuth dependencies caused by source radiation effects. Distributions of HVSR estimates along ~N–S linear array, which traversed main grabens in the region with a station spacing of 3–4 km, reflect subsurface geological complexities in the region. The sites located near the basin edges are characterized by broader HVSR curves. Broad HVSR peaks could be attributed to the complexity of wave propagation related to significant 2D/3D velocity variations at the sediment–bedrock interface near the basin edges. The results also show that, even if the site is located on a horst, the presence of weathered zones along the surface could cause moderate frequency dependent site effects. Comparison of HVSR and SSR estimates for the stations on the graben sites showed that SSR estimates give larger values at lower frequencies which could be attributed to lateral variations in regional velocity and attenuation values caused by basin geometry and edge effects.
KeywordsSite function site resonance frequency horizontal to vertical spectral ratio standard spectral ratio West Turkey
This paper is part of a Bachelor thesis undertaken by Murat Çamyıldız at the Geophysical Engineering Dept. in Dokuz Eylül University (DEU) and of the Ph.D. thesis undertaken by Tevfik Özgür Kurtulmuş at the Institute of Natural and Applied Sciences in the DEU. It is supported by DEU Scientific Research Foundation Grant BAP-Project No: 2008.KB.FEN.08. Base maps in Fig. 1 are taken from Çİftçİ et al. (2010). Figure 2 was produced using public domain software ‘Generic Mapping Tools (GMT)’ (Wessel and Smith, 1995). We thank WASRE network team (Brian Mitchell, Lupei Zhu, Mike Fort, M. Ali Danışman, Oğuz Demir, Zülfikar Erhan, Adem Somer and Emre Timur) for their dedicated efforts during data collection stage. We also thank Lupei Zhu, Aybige Akıncı and Sebastiano D’Amico for their assistance during data processing stage. We are grateful to Brian J. Mitchell for editing English of the text, anonymous reviewers and PAGEOPH associate editor who significantly improved the manuscript.
- Akyol, N., Akinci, A., and Eyİdoğan, H. (2002), Site amplification of S-waves in Bursa city and its vicinity, Northwestern Turkey: Comparison of different approaches, Soil Dynamics and Earthquake Engineering, 22, 579–587.Google Scholar
- Akyol, N., Zhu, L., Mitchell, B. J., Sözbİlİr, H., and Kekovali, K. (2006), Crustal structure and local seismicity in Western Anatolia, Geophysical Journal International, 166, 1259–1269, doi: 10.1111/j.1365-246X.2006.03053.x.
- Aldanmaz, E. (2006), Mineral-chemical constraints on the Miocene calc-alkaline and shoshonitic volcanic rocks of Western Turkey: disequilibrium phenocryst assemblages as indicators of magma storage and mixing conditions, Turkish Journal of Earth Sciences, 15, 47–73.Google Scholar
- Ameri, G., Oth, A., Pilz, M., Bindi, D., Parolai, S., Luzi, L., Mucciarelli, M., and Cultrera, G. (2011), Separation of source and site effects by generalized inversion technique using the aftershock recordings of the 2009 L’Aquila earthquake, Bulletin of Earthquake Engineering, 9, 717–739, doi: 10.1007/s10518-011-9248-4.
- Bindi, D., Parolai, S., cara, F., Di Giulio, G., Ferretti, G., Luzi, L., Monachesi, G., Pacor, F., and Rovelli, A. (2009), Site amplifications observed in the Gubbio basin, Central Italy: hints for lateral propagation effects, Bulletin of the Seismological Society of America, 99, 741–760, doi: 10.1785/0120080238.
- Bindi, D., Luzi, L., Parolai, S., Di Giacomo, D., and Monachesi, G. (2011), Site effects observed in alluvial basins: the case of Norcia (Central Italy), Bulletin of Earthquake Engineering, 9, 1941–1959, doi: 10.1007/s10518-011-9273-3.
- Bonilla, F., Steidl, J.H., Grant, T.L., Alexei, G.T., and Ralph, J.A. (1997), Site amplification in the San Fernando valley, California: variability of site-effects estimation using the S-wave, coda, and H/V methods, Bulletin of the Seismological Society of America, 87, 710–730.Google Scholar
- Borcherdt, R.D., and Gibbs, J.F. (1976), Effects of local geological conditions in the San Francisco Bay region on ground motions and intensities of the 1906 earthquakes, Bulletin of the Seismological Society of America, 66, 467–500.Google Scholar
- Bozkurt, E., and Sözbİlİr, H. (2004), Tectonic evolution of the Gediz Graben: field evidence for an episodic, two-stage extension in western Turkey, Geological Magazine 141, 63–79.Google Scholar
- Cadet, H., Bard, P.Y., and Duval, A.M. (2012), Site effect assessment using KiK-net data: Part 2-site amplification prediction equation based on f(0) and V sz, Bulletin of Earthquake Engineering, 10(2), 451–489, doi: 10.1007/s10518-011-9298-7.
- Castro, R.R., Pacor, F., Bindi, D., Franceschina, G., and Luzi, L. (2004), Site response of strong motion stations in the Umbria, Central Italy region, Bulletin of the Seismological Society of America, 94(2), 576–590.Google Scholar
- Chavez-Garcia, F.J., Stephenson, W.R., and Rodríguez, M. (1999), Lateral propagation effects observed at Parkway, New Zealand. A case history to compare 1D versus 2D site effects, Bulletin of the Seismological Society of America, 89, 718–732.Google Scholar
- Cornou, C., Bard, B.Y., and Dietrich, M. (2003), Contribution of dense array analysis to identification and quantification of basin-edge induced waves. part ii: application to Grenoble basin (French Alps), Bulletin of the Seismological Society of America, 93(6), 2624–2648.Google Scholar
- Çİftçİ, N.B., and Bozkurt, E. (2009), Evolution of the Miocene sedimentary fill of the Gediz graben, SW Turkey, Sedimentary Geology, 216(3–4), 49–79, doi: 10.1016/j.sedgeo.2009.01.004.
- Çİftçİ, N.B., and Bozkurt, E. (2010), Structural evolution of the Gediz graben, SW Turkey: temporal and spatial variation of the graben basin, Basin Research, 22, 846–873, doi: 10.1111/j.1365-2117.2009.00438.x.
- Çİftçİ, N.B., Temel, R.O., and İztan, Y.H. (2010), Hydrocarbon occurrences in the Western Anatolian (Aegean) grabens, Turkey: is there a working petroleum system?, AAPG Bulletin, 94(12), 1827–1857.Google Scholar
- Dewey, J.F., and Şengör, A.M.C. (1979), Aegean and surrounding regions: complex multiple and continuum tectonics in a convergent zone, Geological Society of America Bulletin, 90, 84–92.Google Scholar
- Emre, T., Tavlan, M., Akkİraz, M.S., and İşİntek, İ. (2010), Stratigraphy, sedimentology and palynology of the Neogene-Pleistocene (?) rocks around Akçaşehir-Tire-İzmir (Küçük Menderes graben, Western Anatolia), Turkish Journal of Earth Sciences, 20, 27–56.Google Scholar
- Eskİşar, T., Özyalin, Ş., Kuruoğlu, M., Yılmaz, H.R. (2013). Microtremor measurements in the northern coast of İzmir Bay, Turkey to evaluate site specific characteristics and fundamental periods by H/V spectral ratio method, Journal of Earth System Science, 122(1), 123–136.Google Scholar
- Gessner, K., Ring, U., Christopher, J., Hetzel, R., Passchier, C.W., Güngör, T. (2001), An active bivergent rolling-hinge detachment system: central Menderes metamorphic core complex in western Turkey, Geology, 29, 611–614.Google Scholar
- Hetzel R., Passchier, C.W., Ring, U., and Dora, O.Ö. (1995), Bivergent extension in orogenic belts: the Menderes Massif (southwestern Turkey), Geology, 23, 455–458.Google Scholar
- Işık, M., and Şenel, H. (2009), 3D gravity modeling of Büyük Menderes basin in west Anatolia using parabolic density function, J. Asian Earth Sci., 34(3), 317–325.Google Scholar
- Koeri, (2009), Earthquake Cataloge of Turkey and surrounding region, http://www.koeri.boun.edu.tr/sismo/.
- Le Pichon, X., and Angelier, J. (1979), The Aegean arc and trench system: a key to the neotectonic evolution of the Eastern Mediterranean area, Tectonophysics, 60, 1–42.Google Scholar
- Le Pichon, X., Chamot-Rooke, C., Lallemant, S., Noomen, R., and Veis, G. (1995), Geodetic determination of the kinematics of Central Greece with respect to Europe: implications for Eastern Mediterranean tectonics, Journal of Geophysical Research, 100, 12675–12690.Google Scholar
- Mckenzie, D. (1978), Active tectonics of the Alpine-Himalayan belt: the Aegean sea and surrounding regions, Geophysical Journal of the Royal Astronomical Society, 55, 217–254.Google Scholar
- Malagnini, L., Mayeda, K., Akinci, A., and Bragato, P.L. (2004), Estimating absolute site effects, Bulletin of the Seismological Society of America, 94(4), 1343–1352.Google Scholar
- Mutlu, H. (2007), Constraints on the origin of the Balıkesir thermal waters (Turkey) from stable isotope (δ 18 O, δD, δ 13 C, δ 34 S) and major-trace element compositions, Turkish Journal of Earth Sciences, 16, 13–32.Google Scholar
- Nakamura, Y. (1989), A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface, Quarterly Report of Railway Technical Research Institute, Japan, 30, 25–33.Google Scholar
- Narayan, J.P. (2005), Study of basin-edge effects on the ground motion characteristics using 2.5-D modelling, Pure and Applied Geophysics, 162, 273–289, doi: 10.1007/s00024-004-2600-8.
- Nogoshi, M., and Igarashi, T. (1970), On the propagation characteristics of microtremors, Journal of the Seismological Society of Japan, 23, 264–280 (in Japanese with English abstract).Google Scholar
- Parolai, S., Bindi, D., and Augliera, P. (2000), Application of the generalized inversion technique (GIT) to a microzonation study: numerical sumilations and comparison with different site-estimation techniques, Bulletin of the Seismological Society of America, 90(2), 286–297.Google Scholar
- Parolai, S., and Richwalski, S.M. (2004), The importance of converted waves in comparing H/V and RSM site responses, Bulletin of the Seismological Society of America, 94, 304–313.Google Scholar
- Parolai, S., Bindi, D., Baumbach, M., Grosser, H., Milkereit, C., Karakisa, S., and Zünbül, S. (2004), Comparison of different site response estimation techniques using aftershocks of the 1999 İzmit earthquake, Bulletin of the Seismological Society of America, 94(3), 1096–1108.Google Scholar
- Rojay, B., Toprak, V., Demİrcİ, C., and Süzen, L. (2005), Plio-Quaternary evolution of the Küçük Menderes graben Southwestern Anatolia, Turkey, Geodinamica Acta, 18(3–4), 317–331.Google Scholar
- Sari, C., and Şalk, M. (2006), Sediment thicknesses of the Western Anatolia graben structures determined by 2D and 3D analysis using gravity data, Journal of Asian Earth Sciences, 26, 39–48.Google Scholar
- Sayin, A. (2007), Origin of kaolin deposits: evidence from the Hisarcık (Emet-Kütahya) deposits, Western Turkey, Turkish Journal of Earth Sciences, 16, 77–96.Google Scholar
- Seyİtoğlu, G., and Scott, B.C. (1991), Late Cenozoic crustal extension and basin formation in west Turkey, Geological Magazine, 128, 155–166.Google Scholar
- Seyİtoğlu, G., and Scott, B.C. (1992), The age of Büyük Menderes Graben (west Turkey) and its tectonic implications, Geological Magazine, 129, 239–242.Google Scholar
- Süzen, M.L., Toprak, V., and Rojay, B. (2006), High-altitude Plio Quaternary fluvial deposits and their implication on the tilt of a horst, Western Anatolia, Turkey, Geomorphology, 74(1–4), 80–99.Google Scholar
- Şengör, A.M.C. (1979), The North Anatolian transform fault: its age, offset and tectonic significance, Journal of Geological Society London, 136, 269–282.Google Scholar
- Şengör, A.M.C., Cross-faults and differential stretching of hanging walls in regions of low-angle normal faulting: examples from Western Turkey. In Continental Extensional Tectonics, ed. Coward M.P., Dewey J.F., Hancock P., Geological Society London Special Publications, London 1987, vol. 28, pp 575–589.Google Scholar
- Şengör, A.M.C., Satir, M., and Akkök, R. (1984), Timing of the tectonic events in the Menderes massif, western Turkey: implications for tectonic evolution and evidence for Pan-African basement in Turkey, Tectonics, 3, 693–707.Google Scholar
- Tarcan, G., Fİlİz, Ş., and Gemİcİ, Ü. (2000), Geology and geochemistry of the Salihli geothermal fields, Turkey, World Geothermal Congress, Kyushu-Tohoku, Japan, p.1829–1834.Google Scholar
- Taymaz, T., Jackson, J., and Mckenzie, D. (1991), Active tectonics of the North and Central Aegean Sea, Geophysical Journal International, 106, 433–490.Google Scholar
- Tokçaer, M., Agostini, S., and Şavaşçin, M.Y. (2005), Geotectonic setting and origin of the youngest Kula volcanics (Western Anatolia), with a new emplacement model, Turkish Journal of Earth Sciences, 14, 145–166.Google Scholar
- Wessel, P., and Smith, W.H.F. (1995), New version of the generic mapping tools released, EOS Trans. AGU, 76(33), pp. 329.Google Scholar
- Yilmaz, Y., Genç, S.C., Gürer, O.F., Bozcu, M., Yilmaz, K., Karacik, Z., Altunkaynak, S., and Elmas, A., When did western Anatolian grabens begin to develop? In Tectonics and Magmatism in Turkey and the Surrounding Area, ed. Bozkurt E., Winchester J.A., and Piper J.D.A., Geological Society London Special Publications, London 2000, vol. 173, 353–384.Google Scholar
- Yilmaz, H. (2007), Stream sediment geochemical exploration for gold in the Kazdağ dome in the Biga peninsula, Western Turkey, Turkish Journal of Earth Sciences, 16, 33–55.Google Scholar
- Zhu, L., Akyol, N., Mitchell, B.J., and Sözbİlİr, H. (2006a), Seismotectonics of Western Turkey from high resolution earthquake relocations and moment tensor determinations, Geophysical Research Letters, 33, L07316, doi: 10.1029/2006GL025842.
- Zhu, L., Mitchell, B.J., Akyol, N., Çemen, İ., and Kekovali, K. (2006b), Crustal thickness variations in the Aegean region and its implications for the extension of continental crust, Journal of Geophysical Research, 111, B01301, doi: 10.1029/2005JB003770.