Orta Anadolu’da kabuğa ait sismik P ve S dalga hızı yapısının belirlenmesi

Year 2019, Volume: 25 Issue: 6, 775 - 784, 25.11.2019

İbrahim Hakan Demirsıkan Şakir Şahin Erdinç Öksüm

Abstract

Bu
çalışmada, Orta Anadolu’da yerel depremlerin varış zamanlarından hareketle
Poisson oranı Tomografisi metodu kullanılarak üç boyutlu

(3-B) hız yapısını belirlenmiştir. Bu çerçevede, toplam 27.141 adet depreme ait
109.740 adet P dalgası ve 102.934 adet S dalgası varış zamanı verisi
kullanılmıştır. Depremler Boğaziçi Üniversitesi, Kandilli Rasathanesi ve Deprem
Araştırma Enstitüsü’ne (KRDAE) bağlı Ulusal Pasif Hareket Sismik Ağı’na bağlı
istasyonlar tarafından kaydedilmiştir. İnceleme alanında bulunan deprem
istasyonları ve deprem merkez üssü dağılımı, elde edilen Vp ve Vs hız
dağılımının 40 km’ye kadar güvenilir sonuç verdiğini göstermektedir. Dama
tahtası (Checkerboard) çözünürlük testi ve ışın yolu dağılımları bu durumu
doğrulamaktadır. Tomografik sonuçlar, Orta Anadolu’da kabuk ve üst mantoda
yanal heterojenliklerin varlığına işaret etmektedir. Depremlerin bölgedeki
karmaşık tektonik ve jeolojik yapıdan dolayı genel olarak sismik hızın düştüğü
alanlarda oluştuğu dikkati çekmektedir. Düşük veya yüksek hız değerlerine sahip
olan tüm bölgelerin gerilme enerjisi birikimi için potansiyel alanlar olduğunu
görülmektedir. Elde edilen P ve S dalga hızı modelleri, Orta Anadolu'daki
mevcut sismotektonik yapıyı net bir şekilde ortaya koymaktadır.

Keywords

P ve S dalga hızları, Sismik tomografi, Orta Anadolu, Sismik hız

Determination of seismic P and S wave velocity structure of crust in Central Anatolia

Abstract

In
this study, the three-dimensional (3-D) velocity structure was determined by
Poisson ratio Tomography method based on the arrival time of local earthquakes
in Central Anatolia. For this purpose, 109.740 P-wave and 102.934 S-wave
arrival time data from 27.141 earthquakes were used. Earthquakes were recorded
by stations related to the National Passive Motion Seismic Network of Bogazici
University, Kandilli Observatory and Earthquake Research Institute (KOERI).
Distribution of the stations and earthquake epicenters shows that the Vp and Vs
velocity model yield reliable results up to 40 km depth. Checkerboard
resolution test and ray path distributions confirm this situation. Tomographic
results indicate the presence of lateral heterogeneities in the crust and upper
mantle in Central Anatolia. It is remarkable that the earthquakes occur in
areas where the seismic velocity is low due to the complex tectonic and geological
structure in the region. The results of the study show that all regions with
low or high seismic velocities are potential areas for the accumulation of
stress energy. Resulting P- and S-wave velocity models clearly show the
existing seismotectonic structure in Central Anatolia.

Keywords

P and S wave velocity, Seismic tomography, Center Anatolia, Seismic velocity

References

• Iyer HM. “A review of crust and upper mantle structure studies of the Snake River plain-yellow stone volcanic system: A major lithospheric anomaly in the western USA”. Tectonophysics, 105(1-4), 291-308, 1984.
• Akyol N, Zhu L, Mitchell BJ, Sözbilir H, Kekovalı K. “Crustal structure and local seismicity in western Anatolia”. Geophysical Journal International, 166(3), 1259-1269, 2006.
• Lei J, Zhao D. “Telesismic P-wave tomography and the upper mantle structure of the central Tien Shan orogenic belt”. Physics of the Earth and Planetary Interiors, 162(3), 165-185, 2007.
• Salah MK, Şahin Ş, Topatan U. “Crustal velocity and Vp/Vs structures beneath central Anatolia from local seismic tomography”. Arabian Journal Geosciences, 7(10), 4101-4118, 2014.
• Salah MK, Şahin Ş, Aydin U. “Seismic velocity and Poisson’s ratio tomography of the crust beneath east Anatolia”. Journal of Asian Earth Sciences, 40(3), 746-761, 2011.
• Çıvgın B, Kaypak B. ‘‘Estimation of the crustal structure in Central Anatolia (Turkey) using receiver functions’’. Turkish Journal of Earth Sciences, 26, 314-330, 2017.
• Bozkurt E. “Neotectonics of Turkey - a synthesis”. Geodinamica Acta, 14, 3-30, 2001.
• Maden Tetkik Arama Genel Müdürlüğü. “Türkiye Diri Fay Haritası”. Ankara, Türkiye, 2013.
• Boğaziçi Üniversitesi, Kandilli Rasathanesi ve Deprem Araştırma Enstitüsü, “Türkiye Deprem Verileri Kataloğu”. İstanbul, Türkiye, 2018.
• Zhao D, Hasegawa A, Horiuchi, S. “Tomographic imaging of P- and S-wave velocity structure beneath north eastern Japan”. Journal of Geophysical Research, 97, 19909-19928, 1992.
• Çevikbilen S, Biryol CB, Beck S, Zandt G, Taymaz T, Adıyaman HE, Özacar A. “3-D structure along the North Anatolian Fault Zone in North-Central Anatolia revealed by local earthquake tomography”. Geophysical Journal International, 188(3), 819-849, 2012.
• Um J, Thurber C. “A fast algorithm for two-point seismic ray tracing”. Bulletin Seismological Society of America, 77, 972-986, 1987.
• Zhao D, Hasegawa A, Kanamori H. “Deep structure of Japan subduction zone as derived from local, regional and teleseismic events”. Journal of Geophysical Research, 99, 22313-22329, 1994.
• Thurber CH, Aki K. “Three-dimensional seismic imaging”. Annual Review of Earth and Planetary Sciences, 15, 115-139, 1987.
• Salah MK, Şahin Ş, Destici C. ‘‘Seismic velocity and Poisson’s ratio tomography of the crust beneath southwest Anatolia: an insight into the occurrence of large earthquakes’’. Journal of Seismology, 11, 415-432, 2007.
• Farouk M, Zhao D. “Tomo tools programme for Windows V 1.0”. Geodynamics Research Center (GRC), Ehime University, Japan, Scientific Report, 1, 2006.
• Hearn TM, Ni J. “Pn velocities beneath continental collision zones: the Turkish-Iranian Plateau”. Geophysical Journal International, 117(2), 273-283, 1994.
• Rodgers AJ, Ni JF, Hearn TM. “Propagation characteristics of short period Sn and Lg in the Middle East”. Bulletin Seismological Society of America, 87(2), 396-413, 1997.
• Saunders P, Priestley K, Taymaz T. “Variations in the crustal structure beneath western Turkey”. Geophysical Journal International, 134(2), 373-389, 1998.
• Al-Lazki AI, Sandvol E, Seber D, Barazangi M, Turkelli N, Mohamad R. “Pn tomographic imaging of mantle lid velocity and anisotropy at the junction of the Arabian, Eurasian and African plates”. Geophysical Journal International, 158(3), 1024-1040, 2004.
• Tezel T, Erduran M, Alptekin Ö. “Crustal shear wave velocity structure of Turkey by surface wave dispersion analysis”. Annals Geophysics, 50(2), 177-190, 2007.
• Erduran M, Çakir Ö, Tezel T, Şahin Ş, Alptekin Ö. “Anatolian surface wave evaluated at GEOFON station ISP Isparta, Turkey”. Tectonophysics, 434(1), 39-54, 2007.
• Meier T, Dietrich K, Stöckhert B, Harjes HP. “One-dimensional models of shear wave velocity for the eastern Mediterranean obtained from the inversion of Rayleigh wave phase velocities and tectonic implications”. Geophysical Journal International, 156(1), 45-58, 2004.
• Karagianni EE, Papazachos CB, Panagiotopoulos DG, Suhadolc P, Vuan A, Panza GF. “Shear velocity structure in the Aegean area obtained by inversion of Rayleigh waves”. Geophysical Journal International, 160(1), 127-143, 2005.
• Pasyanos ME. “A variable resolution surface wave dispersion study of Eurasia, North Africa, and surrounding regions”. Journal of Geophysical Research, 110(B12301), 1-22, 2005.
• Maggi A, Priestly K. “Surface waveform tomography of the Turkish-Iranian plateau”. Geophysical Journal International 160(3), 1068-1080, 2005.
• Bilim F. “Investigating Moho depth, Curie Point, and heat flow variations of the Yozgat Batholith and its surrounding area, North central Anatolia, Turkey, using gravity and magnetic anomalies”. Turkish Journal of Earth Sciences, 26, 410-420, 2017.
• Arslan S, Akın U, Alaca A. “Investigation of Crustal Structure of Turkey by Means of Gravity Data”. Bulletin of the Mineral Research and Exploration, 140(140), 55-71, 2010.
• Akın U. “Gravite Verilerinden Türkiye’nin Sismik Hız dağılımı ve Kabuk Yapısının Ortaya Çıkarılması”. Maden Tetkik ve Arama Dergisi, 153,185-202, 2016.
• Ateş A, Bilim, F. Büyüksaraç A, Aydemir A, Bektaş Ö, Aslan Y. “Crustal structure of Turkey from aeromagnetic, gravity and deep seismic reflection data”. Surveys in Geophysics, 33(5), 869-885, 2012.