Electrical conductivity of a locked fault

investigation of the Ganos segment of the North Anatolian Fault using three-dimensional magnetotellurics

Mustafa Karaş, Sabri Bülent Tank, Sinan Özaydin

Research output: Contribution to journalArticle

6 Citations (Scopus)
3 Downloads (Pure)

Abstract

This study attempts to reveal the fault zone characteristics of the locked Ganos Fault based on electrical resistivity studies including audio-frequency (AMT: 10,400–1 Hz) and wide-band (MT: 360–0.000538 Hz) magnetotellurics near the epicenter of the last major event, that is, the 1912 Mürefte Earthquake (M w 7.4). The AMT data were collected at twelve stations, closely spaced from north to south, to resolve the shallow resistivity structure to 1 km depth. Subsequently, 13 wide-band MT stations were arranged to form a grid enclosing the AMT profile to decipher the deeper structure. Three-dimensional inverse modeling indicates highly conductive anomalies representing fault zone conductors along the Ganos Fault. Subsidiary faults around the Ganos Fault, which are conductive structures with individual mechanically weak features, merge into a greater damage zone, creating a wide fluid-bearing environment. This damage zone is located on the southern side of the fault and defines an asymmetry around the main fault strand, which demonstrates distributed conduit behavior of fluid flow. Ophiolitic basement occurs as low-conductivity block beneath younger formations at a depth of 2 km, where the mechanically weak to strong transition occurs. Resistive structures on both sides of the fault beneath this transition suggest that the lack of seismicity might be related to the absence of fluid pathways in the seismogenic zone.
Original languageEnglish
Article number107
Number of pages14
JournalEarth, Planets and Space
Volume69
Issue number1
DOIs
Publication statusPublished - 15 Aug 2017
Externally publishedYes

Bibliographical note

Copyright the Author(s) 2014. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • fluid
  • North Anatolian Fault
  • Ganos Fault
  • Fault zone conductor
  • locked fault
  • electrical resistivity
  • asymmetric damage zone
  • magnetotellurics

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