ABSTRACTDEFINING THE CRUST THICKNESSAND VELOCITY STRUCTURE IN EASTHERN MARMARAMehmet KAPLANIn this study, as a data approximately 6250 earthqaukes? events collected form 17stations operated in the TURKISH NATIONAL TELEMETRIC EARTHQUAKESNETWORK and SAKARYA-BOLU MICRO EARTHQUAKES RECORDNETWORK (SABONET) projects in East Marmara Region were used. In this region,pattern of crust was examined with travel time of body waves recorded in thesenetworks. The graphics of the travel time-epicentral distances were plotted with the datarecorded in distance between 0 and 500 km, and under the stations the thickness andvelocity of layers were determined.V1 , V2 , V3 and V4 are velocities of upper crust, lower crust and Moho transitoriness,respectively. The velocities of upper crust layers were determined as 4.5, 6.2 and 7.2km/sec and thickness of layers of crust were also obtained as 3.8, 14.7 and 20.0 kmrespectively. In the border of mantle, the velocity was determined as 8.0 km/sec andthickness of crust is 38.5 km.KEY WORDS: Body waves, Easthern Marmara, Crust, Velocity.

ÖZETDOGU MARMARA'DA KABUK KALINLIGININVE HIZ YAPISININ BELIRLENMESIMehmet KAPLANBu çalismada, Dogu Marmara Bölgesinde özellikle Bayindirlik ve Iskan Bakanligi AfetIsleri Genel Müdürlügü Deprem Arastirma Dairesi bünyesinde faaliyet gösteren,Turknet (TÜRKIYE ULUSAL TELEMETRIK DEPREM KAYIT AGI) ve Sabonet(SAKARYA - BOLU YÖRESI MIKRODEPREM ÇALISMALARI) projelerindeçalistirilan, toplam 17 adet deprem kayit istasyonlarinca kaydedilen yaklasik 6250 adetdeprem verisi kullanilmistir. Kabuktaki cisim dalgalarinin varis zamanlari kullanilarakelde edilen seyahat zamanlari yardimi ile bölgedeki kabuk yapisi arastirilmistir. 0-500km uzakliklar arasindaki deprem verilerinden yararlanilarak seyahat zamani- uzaklikgrafikleri olusturulmus ve istasyonlarin altindaki tabaka kalinliklari ve hizlaribulunmustur.V1, V2 ve V3 sirasiyla kabuk kalinliklarini ve V4 Moho süreksizligi altindaki hizigöstermektedir. Kabuk hizlarinin sirasiyla 4.5, 6.2 ve 7.2 km/sn tabaka kalinliklarininise 3.8, 14.7 ve 20.0 km oldugu tespit edilmistir. Manto sinirindaki hiz degerlerinin ise8.0 km/sn ve derinliginin de 38.5 km oldugu belirlenmistir.ANAHTAR KELIMELER: Cisim dalgalari, Dogu Marmara, Kabuk, Sismik hiz.