GÜLTEN POLAT, Nurcan Meral ÖZEL, STUART CRAMPIN

3111

Preliminary Investigating results from Azimuthal Seismic Anisotropy beneath Western Anatolia and the Hellenic Subduction Zone

To understand the dynamics of a subduction zone, seismic anisotropy is often used, despite the difficulty of constraining anisotropy in the sub-slab region. However, particularly due to constraints imposed by deformation patterns in the mantle surrounding subducting slabs, seismic anisotropy is usually chosen as a better tool. In this study, the dynamics and kinematics of the Hellenic subduction zone and its impact on mantle convection related deformation are investigated by using source-side seismic anisotropy. To this aim, shear wave splitting parameters of local and teleseismic S waves from intermediate and shallow earthquakes are measured. Then, they are combined with splitting parameters obtained from teleseismic SKS and SKKS waves in order to determine variations in seismic anisotropy with depth. Although in the study area strong deep earthquakes are not available, our preliminary splitting results are quite reliable. Also, they are fairly consistent with the presence of azimuthal seismic anisotropy in the asthenosphere below the slab. The averaged fast polarization directions obtained from the analysed teleseismic events show N-S orientations. Additionally, we observed that S-wave fast polarization directions are nearly parallel to the present extension direction of Western Anatolia. It might be suggested that anisotropy may localize within the lower crust, but does not appear to be associated with the present lithospheric extension. Average delay time of teleseismic SKS is greater than 1 s.
Anahtar Kelimeler:

kaynak-yanı anizotropi, kesme dalgası ayrımlanması, yitim zonu, Ege bölgesi

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  • Ando, M., Ishikawa, Y. and Wada, H., 1980. S-wave anisotropy in the upper mantle under a volcanic area in Japan. Nature, 286, 43–46.
  • Ando, M., Ishikawa, Y., Yamazaki, F., 1983. Shear wave polarization anisotropy in the upper mantle beneath Honshu. Journal of Geophysical Research, 88, 5850–5864.
  • Backus, G. , 1962. Long-wave elastic anisotropy produced by horizontal layering. Journal of Geophysical Research, 67, 4427–4440.
  • Booth, D.C. and Crampin, S., 1985. Shear-wave polarizations on a curved wavefront at an isotropic free-surface. Geophysical Journal of the Royal Astronomical Society, 83, 31-45.
  • Christensen, N. I., 1984. The magnitude, symmetry and origin of up- per mantle anisotropy based on fabric analyses of ultramafic tectonics. Geophysical Journal of the Royal Astronomical Society, 76, 89-112.
  • Crampin, S., 1978. Seismic wave propagation through a cracked solid: polarization as a possible dilatancy diagnostic. Geophysical Journal of the Royal Astronomical Society, 53, 467-496.
  • Cochran, E. S., Vidale, J. E., and Li, Y. G., 2003. Near-fault anisotropy following the Hector Mine earthquake. Journal of Geophysical Research, 108, 2436, doi: 10.1029/2002JB002352.
  • Di Leo, J., Walker, A., Li, Z.-H., Wookey, J., Ribe, N., Kendall, J.-M. and Tommasi, A., 2014. Development of texture and seismic anisotropy during the onset of subduction. Geochemistry, Geophysics, Geosystems, 15, 192–212, doi:10.1002/2013GC005032.
  • Eakin, C.M., Long, M.D.,Wagner, L.S., Beck, S.L., Tavera, H., 2015. Upper mantle anisotropy beneath Peru from SKS splitting: Constraints on flat slab dynamics and interaction with the Nazca Ridge. Earth and Planetary Science Letters, 412:152–162. ttp://dx.doi. org/10.1016/j.epsl.2014.12.015.
  • Evangelidis, C., Liang, W., Melis, N. S. and Konstantinou, K. I., 2011. Shear wave anisotropy beneath the Aegean inferred from SKS splitting observations. Journal of Geophysical Research, 116, B04, 314, doi: 10.1029/2010JB007884.
  • Faccenna, C., Bellier, O., Martinod, J., Piromallo, C., and Regard, V., 2006. Slab detachment beneath eastern Anatolia: A possible cause for the formation of the North Anatolian fault. Earth and Planetary Science Letters, 242, 85–97.
  • Faccenda, M., and Capitanio, 2012. Development of mantle seismic anisotropy during subduction-induced 3-D flow. Geophysical Research Letters, 39, L11305, doi: 10.1029/2012GL051988.
  • Faccenda, M., and Capitanio, F., 2013. Seismic anisotropy around subduction zones: Insights from three-dimensional modeling of upper mantle deformation and SKS splitting calculations. Geochemistry, Geophysics, Geosystems, 14, 243–262, doi:10.1002/ ggge.20055.
  • Hall, C. E., Fischer, K. M., Parmentier, E. M., and Blackman, D. K., 2000. The influence of plate motions on three-dimensional back arc mantle flow and shear wave splitting, Journal of Geophysical Research, 105(B12), 28009–28033, doi:10.1029/2000JB900297.
  • Hatzfeld, D., 2001. Shear wave anisotropy in the upper mantle beneath the Aegean related internal deformation, Journal of Geophysical Research: Solid Earth, 106, 30 737-30 754.
  • Karato, S.-I., Zhang, S. and Wenk, H.-R., 1995. Super-plasticity in the Earth’s lower mantle: Evidence from seismic anisotropy and rock physics, Science, 270, 458–461.
  • Karato, S. , 2008. Deformation of Earth Materials: Introduction to the Rheology of the Solid Earth, 462. pp.,
  • Cambridge University Press, Cambridge, U.K.
  • Kawakatsu, H.,and Yoshioka, S., 2011. Metastale olivine wedge and deep dry cold slab beneath southwest Japan, Earth and Planetary Science Letters, 303, 1-10,doi:10.1016/j. epsi.2011.01.008.
  • Kubo, T., Ohtani, E., Kato, T., Urakawa, S., Suzuki, A., Kanbe, Y., Funakoshi, K., Utsumi, W., Kikegawa,T., Fujino, K., 2002. Mechanisms and kinetics of the post–spinel transformation in Mg2SiO4. Physics of the Earth and Planetary Interiors, 129, 153–171.
  • Li, Z.-Hai., Di Leo, J.F., and Ribe, N. M., 2014. Subduction-induced mantle flow, finite train, and seismic anisotropy: Numerical modeling. Journal of Geophysical Research: Solid Earth, 119, 5052–5076, doi:10.1002/2014JB010996.
  • Long, M.D. and van der Hilst, R.D., 2005. Upper mantle anisotropy beneath Japan from shear wave splitting. Physics of the Earth and Planetary Interiors, 151, 206–222.
  • Long, M. and Silver, P. G., 2009. Shear wave splitting and mantle anisotropy: measurements, interpretations, and new directions. Surveys in Geophysics, 30, 407–461.
  • Lynner, C., and Long, M. D., 2014. Sub-slab anisotropy beneath the Sumatra and circum-Pacific subduction zones from source-side shear wave splitting observations. Geochemistry, Geophysics, Geosystems, 15, doi:10.1002/2014GC005239.
  • Lynner, C., Long, M.D., Thissen, C.J., Paczkowski, K., and Montési, L.G.J., 2017. Evaluating geodynamic models for sub-slab anisotropy: Effects of olivine fabric type. Geosphere, v. 13, no. 2, p. 247–259, doi:10.1130/ GES01395.1.
  • Mainprice, D., 2007. Seismic anisotropy of the deep Earth from a mineral and rock physics perspective, in Treatise on Geophysics, vol. 2, edited by G. Schubert, pp. 437–492, Elsevier, Oxford, U.K.
  • Meissner, R., Rabbel, W., and Kern, H., 2006. Seismic lamination and anisotropy of the Lower Continental Crust. Tectonophysics, 416, 81–99.
  • Nuttli, O., 1961. The effects of the Earth’s surface on the S wave particle motion. Bulletin of the Seismological Society of America, 51, 237–246, 1961.
  • Ohtani, E., Litasov, K., Hosoya, T., Kubo, T. and Kondo, T., 2004. Water transport into the deep mantle and formation of a hydrous transition zone. Physics of the Earth and Planetary Interiors, 143, pp.255-269.
  • Polat, G., 2006. Shear wave splitting for Turkey, M.S. in Geophysics Department, Bogazici University Kandilli Observatory and Earthquake Research Institute, Istanbul-Turkey.
  • Polat, G., Ozel, N. M., Crampin, S., Ergintav, S., and Tan, O.: Shear wave splitting as a proxy for stress forecast of the case of the 2006 Manyas-Kus Golu (Mb = 5.3) earthquake, Natural Hazards and Earth System Sciences, 12, 1073-1084, doi:10.5194/ nhess-12-1073-2012. Russo, R. M., and Silver, P. G., 1994. Trench-parallel flow beneath the Nazca plate from seismic anisotropy, Science, 263, 1105–1111. Savage, M. K., 1999. Seismic anisotropy and mantle deformation: What have we learned from shear wave splitting?, Reviews of Geophysics, 37, 65–106, doi:10.1029/98RG02075.
  • Shih, O. R. and Meyer, P. R., 1990. Observation of Shear Wave Splitting From Natural Events “South Moat of Long Valley Caldera”, California, June 29 to August 12, 1982, Journal of Geophysical Research, 95, 11179–11195.
  • Silver, P.G. and Chan, W. W., 1991. Shear wave splitting and subcontinental mantle deformation, Journal of Geophysical Research, 96, 16429-16454.
  • Silver, P. G., 1996. Seismic Anisotropy Beneath the Continents: Probing the Depths of Geology. Annual Review of Earth and Planetary Sciences, 24, 385–432, doi:10.1146/annurev. earth.24.1.385.
  • Vauchez, A., Tommasi A., Barruol, G., and J. Maumus, J., 2000. Upper mantle deformation and seismic anisotropy in continental rifts, Physics and Chemistry of the Earth V. 25, 111–117.
  • Teanby, N., Kendall, J.-M. , Jones, R. H. and Barkved, O., 2004. FAST TRACK PAPER: Stress induced temporal variations in seismic anisotropy observed in microseismic data. Geophysical Journal International, 156, 459–466, doi:10.1111/j.1365-246X.2004.02212.x.
  • Zatsepin, S. V. and Crampin, S., 1997. Modelling the compliance of crustal rock: I-response of shear-wave splitting to differential stress, Geophysical Journal International, 129,477–494.
  • Zhang, S., and Karato, S., 1995. Lattice preferred orientation of olivine aggregates deformed in simple shear. Nature, 375, 774–777. Zimmerman, M.E., Zhang, S., Kohlstedt, D.L., Karato, S., 1999. Melt distribution in mantle rocks deformed in shear. Geophysical Research Letters 26, 1505–1508.
Yerbilimleri-Cover
  • ISSN: 1301-2894
  • Başlangıç: 1976
  • Yayıncı: Hacettepe Üniversitesi Yerbilimleri Uygulama ve Araştırma Merkezi
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