Field evidence for normal fault linkage and relay ramp evolution: the Krkaac Fault Zone, western Anatolia (Turkey)


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UZEL B.

GEODINAMICA ACTA, vol.28, no.4, pp.311-327, 2016 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 28 Issue: 4
  • Publication Date: 2016
  • Doi Number: 10.1080/09853111.2016.1184778
  • Journal Name: GEODINAMICA ACTA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.311-327
  • Keywords: normal fault, relay ramp, paleostress inversion, the Krkaac Fault Zone, western Anatolia, METAMORPHIC CORE COMPLEX, SOUTHERN MENDERES MASSIF, BALIKESIR TRANSFER ZONE, ACTIVE MANISA FAULT, GEDIZ GRABEN, TECTONIC EVOLUTION, SEGMENT LINKAGE, STRUCTURAL EVIDENCE, 2-STAGE EXTENSION, BASIN FORMATION
  • Dokuz Eylül University Affiliated: Yes

Abstract

Linking of normal faults forms at all scales as a relay ramp during growth stages and represents the most efficient way for faults to lengthen during their progressive formation. Here, I study the linking of normal faulting along the active Krkaac Fault Zone within the west Anatolian extensional system to reconstruct fault interaction in time and space using both field- and computer-based data. I find that (i) connecting of the relay zone/ramp occurred with two breaching faults of different generations and that (ii) the propagation was facilitated by the presence of pre-existing structures, inherited from the zmir-Balkesir transfer zone. Hence, the linkage cannot be compared directly to a simple fault growth model. Therefore, I propose a combined scenario of both hangingwall and footwall fault propagation mechanisms that explain the present-day geometry of the composite fault line. The computer-based analyses show that the approximate slip rate is 0.38mm/year during the Quaternary, and a NE-SW-directed extension is mainly responsible for the recent faulting along the Krkaac Fault Zone. The proposed structural scenario also highlights the active fault termination and should be considered in future seismic hazard assessments for the region that includes densely populated settlements.