Asymmetric slip partitioning in the Sea of Marmara pull-apart: a clue to propagation processes of the North Anatolian Fault?

Armijo R., Meyer B., Navarro S., King G., Barka A.

TERRA NOVA, vol.14, no.2, pp.80-86, 2002 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 14 Issue: 2
  • Publication Date: 2002
  • Doi Number: 10.1046/j.1365-3121.2002.00397.x
  • Journal Name: TERRA NOVA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.80-86
  • Istanbul Technical University Affiliated: No


Between 1939 and 1999 the North Anatolian fault (NAF) experienced a westward progression of eight large earthquakes over 800 km of its morphological trace. The 2000-km-long North Anatolian transform fault has also grown by westward propagation through continental lithosphere over a much longer timescale (similar to10 Myr). The Sea of Marmara is a large pull-apart that appears to have been a geometrical/mechanical obstacle encountered by the NAF during its propagation. The present paper focuses on new high-resolution data on the submarine fault system that forms a smaller pull-apart beneath the Northern Sea of Marmara, between two well-known strike-slip faults on land (Izmit and Ganos faults). The outstandingly clear submarine morphology reveals a segmented fault system including pull-apart features at a range of scales, which indicate a dominant transtensional tectonic regime. There is no evidence for a single, continuous, purely strike-slip fault. This result is critical to understanding of the seismic behaviour of this region of the NAF, close to Istanbul. Additionally, morphological and geological evidence is found for a stable kinematics consistent both with the long-term displacement field determined for the past 5 Myr and with present-day Anatolia/Eurasia motion determined with GPS. However, within the Sea of Marmara region the fault kinematics involves asymmetric slip partitioning that appears to have extended throughout the evolution of the pull-apart. The loading associated with the westward propagation process of the NAF may have provided a favourable initial geometry for such a slip separation.