Palaeoseismology of the North Anatolian Fault near the Marmara Sea: implications for fault segmentation and seismic hazard THOMAS ROCKWELL1*, DANIEL RAGONA1, GORDON SEITZ1, ROB LANGRIDGE2, M. ERSEN AKSOY3,GU¨ LSEN UCARKUS3, MATTHIEU FERRY4,7, ARON J. MELTZNER5, YANN KLINGER6, MUSTAPHA MEGHRAOUI7, DILEK SATIR3, AYKUT BARKA3† & BURCAK AKBALIK3 1Geological Sciences, San Diego State University, San Diego, CA 92182, USA 2Institute of Geological and Nuclear Sciences, PO Box 30-368, Lower Hutt, New Zealand 3Eurasia Institute of Earth Sciences, Istanbul Technical University, Maslak, Istanbul, Turkey 4Universidade de E´ vora, Centro de Geofisica de E´ vora, Rua Roma˜o Ramalho 59, 7002-554 E´ vora, Portugal 5Tectonics Observatory, California Institute of Technology, Pasadena, CA 91125, USA 6Laboratoire de Tectonique, Institut de Physique du Globe, 4 place Jussieu, 75005, Paris, France 7Institut de Physique de Globe, 5 rue Rene´ Descartes, F-67084 Strasbourg Cedex, France †Deceased *Corresponding author (e-mail:
[email protected]) Abstract: We conducted palaeoseismic studies along the North Anatolian fault both east and west of the Marmara Sea to evaluate its recent surface rupture history in relation to the well-documented historical record of earthquakes in the region, and to assess the hazard of this major fault to the city of Istanbul, one of the largest cities in the Middle East. Across the 1912 rupture of the Ganos strand of the North Anatolian fault west of the Marmara Sea, we excavated 26 trenches to resolve slip and constrain the earthquake history on a channel–fan complex that crosses the fault at a high angle. A distinctive, well-sorted fine sand channel that served as a marker unit was exposed in 21 trenches totaling over 300 m in length.