A 3800 yr paleoseismic record (Lake Hazar sediments, eastern Turkey): Implications for the East Anatolian Fault seismic cycle

Hubert‐Ferrari, Aurélia; Lamair, Laura; Hage, Sophie; Schmidt, Sabine; Ćaǧatay, M. Namık; Avşar, Ulaş

doi:10.1016/j.epsl.2020.116152

Cited by 39 publications

(36 citation statements)

References 39 publications

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“…years is difficult to explain with the "flood hypothesis". However, given the active tectonic context of the region, it is plausible that such turbidites are related to shallow slope destabilizations by recurrent earthquakes, as previously proposed for thin turbidites in a similar context of Lake Hazar (~ 900 km southeastward on the East Anatolian Fault; Hage et al, 2017;Hubert-Ferrari et al, 2020). To evaluate this potential seismic cause, the age of the turbidites, deduced from age models of cores IZN19_21 and IZN19_31…”

Section: Event Deposits Versus Seismic Historical Archivesmentioning

confidence: 99%

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

Gastineau

Sigoyer

Sabatier

et al. 2020

Preprint

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Key points: 1. Previously unknown faults that belong to the North Anatolian Fault system have been discovered in Lake Iznik through geophysical surveys (from multibeam bathymetry and high-frequency seismic reflection data). 2. Assessment of the recent activity of the Iznik Fault, based on multiproxy analysis of sediment cores from each side of the fault. 3. Evidence for the timing of the last rupture corresponding to the 1065 CE historical earthquake, which had significantly impacted the city of Iznik.

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Section: Event Deposits Versus Seismic Historical Archivesmentioning

confidence: 99%

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

Gastineau

Sigoyer

Sabatier

et al. 2020

Preprint

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“…Furthermore, its relations to large historical ruptures in 1874 and 1875 (to the NE) and 1893 and 1905 (to the SW) (Ambraseys, 1989; Figure 1c) could provide an informative test of the characteristic earthquake and seismic gap models (Kagan et al., 2012; McCann et al., 1979; Schwartz & Coppersmith, 1984). Documenting the surface expression of the Elazığ earthquake also provides important context to paleoseismic studies of the EAF (Cetin et al., 2003; Garcia Moreno et al., 2011; Hubert‐Ferrari et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

The 2020 M_w 6.8 Elazığ (Turkey) Earthquake Reveals Rupture Behavior of the East Anatolian Fault

Pousse‐Beltran

Nissen

Bergman

et al. 2020

Geophysical Research Letters

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The 2020 Mw 6.8 Elazığ earthquake was the largest along the East Anatolian Fault (EAF) in over a century, providing valuable insights into its rupture behavior. We use satellite geodesy and seismology to detail the mainshock rupture, postseismic deformation, and aftershocks. The mainshock propagated mostly westward at ∼2 km/s from a nucleation point on an abrupt ∼10° fault bend. Only one end of the rupture corresponds to an established EAF segment boundary, and the earthquake may have propagated into the slip zone of the 1874 M ∼ 7.1 Gölcuk Gölu earthquake. It exhibits a pronounced (∼80%) shallow slip deficit, only a small proportion of which is recovered by early aseismic afterslip. The slow rupture velocity, shallow slip deficit, and minimal afterslip are characteristic of earthquakes hosted by faults of low‐to‐intermediate structural maturity, indicating that faults continue to evolve in important ways even as they accrue cumulative offsets of tens of kilometers.

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“…The frequency of these turbidites and in particular the fact that no deposit has been observed over the last 1,000 years is difficult to explain with the "flood hypothesis.". However, given the active tectonic context of the region, it is plausible that such turbidites are related to shallow slope destabilizations by recurrent earthquakes, as previously proposed for thin turbidites in a similar context of Lake Hazar (~900 km southeastward on the East Anatolian Fault; Hage et al, 2017;Hubert-Ferrari et al, 2020). To evaluate this potential seismic cause, the age of the turbidites, deduced from age models of cores IZN19_21 and IZN19_31 are compared with those of the historical earthquakes in a broader area (Ambraseys & Finkel, 1991;Ambraseys & Jackson, 2000;Ambraseys, 2002Ambraseys, , 2009Guidoboni & Comastri, 2005; Tables S1 and S2 in the supporting information).…”

Section: 1029/2020tc006404mentioning

confidence: 71%

Active Subaquatic Fault Segments in Lake Iznik Along the Middle Strand of the North Anatolian Fault, NW Turkey

et al. 2021

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The seismic activity of the middle strand of the North Anatolian Fault (MNAF), Northwestern Turkey, is debated because of its quiescence during the instrumental period, in contrast to a significant historical activity documented by several chronicles over the last two millennia. Here, we focus on Lake Iznik, bordered by the MNAF, to get a new insight into its long-term seismicity and its tectonic setting. The study of lacustrine sediment cores reveals 14 earthquake-induced turbidites since their ages correspond to seismic events during the past two millennia. Bathymetry and high-resolution seismic reflection data allow to describe two hitherto unknown subaquatic active fault structures (the South Boyalica and Iznik faults) that belong to the MNAF system. Sediment cores sampled on both sides of the Iznik Fault document an event deposit and a sedimentary unit vertically offset of~40 cm interpreted as the last rupture during the 1065 CE destructive earthquake. Older events are supposed on this fault more than thousand years ago. Further studies will help to estimate the horizontal co-seismic offset of this oblique-slip fault and the calendar of older ruptures. The current seismic gap of thousand years on this segment greatly increases the seismic hazard in this region and must be considered in the seismic risk assessment of the NAF system. Plain Language Summary During large earthquakes, sediments are generally transported from lake slopes to the lake basin. The resulting event deposits can provide information on the recurrence of past regional earthquakes, which is crucial for seismic hazard assessment. In this study, we discovered two underwater fault structures in Lake Iznik, using geophysical methods. Studying the sedimentation on both sides of the southernmost fault, we observed an increased sedimentation rate on the hanging wall of the fault immediately after an event deposit, dated to 1077 ± 77 cal. CE. We interpreted these indicators as resulting from a co-seismic displacement along the fault plane, linked to the 1065 CE historical earthquake, which had significantly impacted the city of Iznik. We also show that most of the other event deposits in the sediment cores are confidently associated to 14 historical earthquakes since 2,000 years.

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A 3800 yr paleoseismic record (Lake Hazar sediments, eastern Turkey): Implications for the East Anatolian Fault seismic cycle

Cited by 39 publications

References 39 publications

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

The 2020 M_w 6.8 Elazığ (Turkey) Earthquake Reveals Rupture Behavior of the East Anatolian Fault

Active Subaquatic Fault Segments in Lake Iznik Along the Middle Strand of the North Anatolian Fault, NW Turkey

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A 3800 yr paleoseismic record (Lake Hazar sediments, eastern Turkey): Implications for the East Anatolian Fault seismic cycle

Cited by 39 publications

References 39 publications

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

Active subaquatic fault segments in Lake Iznik along the middle strand of the North Anatolian Fault, NW Turkey

The 2020 Mw 6.8 Elazığ (Turkey) Earthquake Reveals Rupture Behavior of the East Anatolian Fault

Active Subaquatic Fault Segments in Lake Iznik Along the Middle Strand of the North Anatolian Fault, NW Turkey

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The 2020 M_w 6.8 Elazığ (Turkey) Earthquake Reveals Rupture Behavior of the East Anatolian Fault