Catastrophic events analysed by a multi-proxy approach using lake sediments from the North Anatolian Fault area, N-W Turkey
by
Suzanne Leroy
Department of Geography and Earth Sciences and Institute for the Environment, Brunel University, Uxbridge UB8 3PH, UK
Coauthors: Werner, P. and Schwab, M.J.

The aim of this research is to develop a multi-proxy technique for identifying earthquake signals in lake sediment. A belt of lakes that straddles the western strands of the North Anatolian Fault (NAF), N-W Turkey, offers possibilities for establishing Holocene earthquake histories.

Lake Sapanca, east of the Gulf of Izmit, lies in a large pull-apart basin formed by a step-over between the Sapanca and Sakarya segments of the fault. The sediments of Lake Sapanca have most recently been disturbed by lateral spreading near Esme City during the Mw 7.0 July 22 1967 Mudurnu Valley earthquake and directly disturbed by faulting and lateral spreading during the Mw 7.4 August 17 1999 Kocaeli earthquake.

A short gravity corer was used to sample the predominantly clay sediments of Lake Sapanca at 12 sites along three transects. We present a high-resolution study of the upper 30 to 40 cm of sediments deposited in Lake Sapanca using a multi-disciplinary palaeolimnological analysis.

Two lakes, Manyas and Ulubat, south of the Marmara Sea, have been cored to explore the possible impact of a cluster of earthquakes on the NAF on the collapse of an arboricultural civilisation (the Beysehir Occupation Phase, BOP) at the beginning of the Byzantine Empire against a background of deteriorating climatic conditions.

The three lakes show major modifications of the environment directly or indirectly due to the impact of tectonic activity.

Date received: January 14, 2005