3-D electromagnetic imaging of highly deformed fluid-rich weak zones and locked section of the North Anatolian fault beneath the Marmara Sea


Kaya-Eken T., Ogawa Y., Usui Y., Kasaya T., TUNÇER M. K., Honkura Y., ...More

GEOLOGY, vol.54, no.3, pp.200-204, 2026 (SCI-Expanded, Scopus) identifier

  • Publication Type: Article / Article
  • Volume: 54 Issue: 3
  • Publication Date: 2026
  • Doi Number: 10.1130/g52995.1
  • Journal Name: GEOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Artic & Antarctic Regions, Compendex, Environment Index, Geobase, DIALNET, Nature Index
  • Page Numbers: pp.200-204
  • Istanbul University Affiliated: No

Abstract

Reliable knowledge of the crustal properties beneath the North Anatolian fault (NAF), seismically silent for more than 250 years beneath the Marmara Sea (MS), is crucial for un-derstanding seismic hazard and mitigating the potential for disaster on an enormous scale. In the present work, the first three-dimensional inverse modeling performed on a magneto-telluric dataset of the MS has unveiled localized weak and locked fault segments along this shear deformation zone. Low-resistivity regions along the northern branch of the NAF be-neath the Central and & Ccedil;& imath;narc & imath;k-Imral & imath; basins are likely attributed to the presence of fluids, which may represent a fault zone conductor in a fractured zone and can explain the densely populated microseismicity. These low-resistivity anomalies surrounded by higher resistivity structures imply that the segmented, multi-branched NAF system extends beneath the MS, following the Intra-Pontide suture zone. The resistive anomalies, between the Central and & Ccedil;& imath;narc & imath;k basins, along with those at the western and eastern extremities of the MS, presum-ably signify regions of stress accumulation, shedding light on the ongoing processes of fault mechanics at play in this critical region.