HR: 1340h
AN: T53B-0481    [Abstracts]
TI: Seismotectonics of Western Turkey: A Synthesis of Source Parameters and Rupture Histories of Recent Earthquakes
AU: * Taymaz, T
EM: taymaz@itu.edu.tr
AF: Istanbul Technical University, the Faculty of Mines Department of Geophysics Maslak Campus, ISTANBUL, TR-34390 Turkey
AU: Tan, O
EM: tano@itu.edu.tr
AF: Istanbul Technical University, the Faculty of Mines Department of Geophysics Maslak Campus, ISTANBUL, TR-34390 Turkey
AU: Yolsal, S
EM: yolsalse@itu.edu.tr
AF: Istanbul Technical University, the Faculty of Mines Department of Geophysics Maslak Campus, ISTANBUL, TR-34390 Turkey
AB: The Aegean region, including western Turkey and Greece, is indeed one of the most seismically active and rapidly deforming continental domains in the Earth. The wide range of deformational processes occurring in this region means that the eastern Mediterranean provides a unique opportunity to improve our understanding of the complex kinematics of continental collision, including strike-slip faulting and crustal extension, as well as associated seismicity and volcanism. The tectonic evolution of the Eastern Mediterranean region is dominated by effects of subduction along the Hellenic (Aegean) arc and of continental collision in eastern Anatolia and the Caucasus. Northward subduction of the African plate beneath western Anatolia and the Aegean region is causing crustal extension in the overlying Aegean province. The interplay between dynamic effects of the relative motions of adjoining plates thus controls large-scale crustal deformation and the associated earthquake activity in Turkey. The Aegean region has been subject to extension since Miocene time, and this extension has left a pronounced expression in the present-day topography. It is further widely accepted that the rapid extension observed in western Turkey is mainly accommodated by large active normal faults that control the geomorphology which is dominated by a series of E-W trending normal-fault-bounded horst and graben structures; the N-S extension inferred from these structures is consistent with regional earthquake focal mechanisms. The E-W trending Menderes graben, the NE-SW trending Burdur, Acigol and Baklan, and NW-SE trending Dinar and Sultandag-Aksehir basins all bounded by large faults form a system of half-graben whose orientation is evident in both the topography and the tilting of Neogene sediments adjacent to them. We have studied source mechanisms and rupture histories of $\sim$20 earthquakes using body-waveform modelling, and have compared the shapes and amplitudes of teleseismic long-period P-, SH-, and broadband P-waveforms recorded by GDSN stations in the distance range of 30$\deg$-90$\deg$. The final solutions were also constrained by P-wave first motion polarities of near-field stations. They all exhibit the characteristics and structural complexities associated with strike-slip and normal faulting as a result of ongoing crustal deformation. We found strike, dip, rake, centroid depth, seismic moment, and source time functions and rupture history and slip distributions.
DE: 7230 Seismicity and seismotectonics
DE: 8107 Continental neotectonics
DE: 8123 Dynamics, seismotectonics
DE: 7203 Body wave propagation
DE: 7215 Earthquake parameters
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting