Constraints on North Anatolian Fault zone width in the crust and upper mantle from S-wave teleseismic tomography

Papaleo, Elvira; Cornwell, David G.; Rawlinson, Nicholas

doi:10.31223/osf.io/jskw7

Cited by 9 publications

(19 citation statements)

References 47 publications

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“…The crustal structure in our study region has been characterised using a wide variety of geophysical techniques including seismic refraction (Karahan et al, 2001;Horasan et al, 2002;Bekler & Gürbüz, 2008), ambient noise (Taylor et al, 2016(Taylor et al, , 2019a, receiver functions (Vanacore et al, 2013;Jenkins et al, 2020), local earthquake tomography (Bariş et al, 2005;Koulakov et al, 2010;Beyhan & Alkan, 2015;Polat et al, 2016;Yolsal-Çevikbilen et al, 2012), magnetotellurics (Tank et al, 2005), and regional full waveform tomography (Fichtner et al, 2013;Çubuk-Sabuncu et al, 2017). Similarly, the upper mantle has been studied using receiver functions (Kind et al, 2015;Taylor et al, 2019b), seismic anisotropy (Biryol et al, 2010;Paul et al, 2014;Lemnifi et al, 2017;Legendre et al, 2021) and body and surface wave tomography (Berk Biryol et al, 2011;Bakırcı et al, 2012;Salaün et al, 2012;Fichtner et al, 2013;Govers & Fichtner, 2016;Papaleo et al, 2017Papaleo et al, , 2018.…”

Section: Tectonics and Previous Geophysical Surveysmentioning

confidence: 99%

“…Tomographic studies using traveltimes from local, regional and teleseismic events (e.g. Bariş et al, 2005;Salah et al, 2007;Koulakov et al, 2010;Bakırcı et al, 2012;Beyhan & Alkan, Scattering Tomography NW North Anatolian Fault 9 2015; Polat et al, 2016;Papaleo et al, 2017Papaleo et al, , 2018 and full waveform information (e.g. Fichtner et al, 2013;Govers & Fichtner, 2016;Çubuk-Sabuncu et al, 2017;Blom et al, 2020) find strong velocity contrasts in the crust along the NNAFZ and the SNAFZ.…”

Section: Scattering Tomography Nw North Anatolian Faultmentioning

confidence: 99%

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Structure of the northwestern North Anatolian Fault Zone imaged via teleseismic scattering tomography

Rost

Houseman

Frederiksen

et al. 2021

Geophysical Journal International

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Summary Information on fault zone structure is essential for our understanding of earthquake mechanics, continental deformation and seismic hazard. We use the scattered seismic wavefield to study the subsurface structure of the North-Anatolian Fault Zone (NAFZ) in the region of the 1999 İzmit and Düzce ruptures using data from an 18-month dense deployment of seismometers with a nominal station spacing of 7 km. Using the forward- and back-scattered energy that follows the direct P-wave arrival from teleseismic earthquakes, we apply a scattered wave inversion approach and are able to resolve changes in lithospheric structure on a scale of 10 km or less in an area of about 130 km by 100 km across the NAFZ. We find several crustal interfaces that are laterally incoherent beneath the surface strands of the NAFZ and evidence for contrasting crustal structures either side of the NAFZ, consistent with the presence of juxtaposed crustal blocks and ancient suture zones. Although the two strands of the NAFZ in the study region strike roughly east-west, we detect strong variations in structure both north-south, across boundaries of the major blocks, and east-west, parallel to the strike of the NAFZ. The surface expression of the two strands of the NAFZ is coincident with changes on main interfaces and interface terminations throughout the crust and into the upper mantle in the tomographic sections. We show that a dense passive network of seismometers is able to capture information from the scattered seismic wavefield and, using a tomographic approach, to resolve the fine scale structure of crust and lithospheric mantle even in geologically complex regions. Our results show that major shear zones exist beneath the NAFZ throughout the crust and into the lithospheric mantle, suggesting a strong coupling of strain at these depths.

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Section: Tectonics and Previous Geophysical Surveysmentioning

confidence: 99%

Section: Scattering Tomography Nw North Anatolian Faultmentioning

confidence: 99%

Structure of the northwestern North Anatolian Fault Zone imaged via teleseismic scattering tomography

Rost

Houseman

Frederiksen

et al. 2021

Geophysical Journal International

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“…The Dead Sea Transform (DST; Figure 1; e.g., Weber et al., 2009), which connects to the East Anatolian Fault Zone, has formed along other preexisting crustal weak zones to accommodate differential motion between Africa and Arabia after continental collision. Both are major active plate boundaries, yet consensus is lacking on their expression in the lithospheric mantle (e.g., Çubuk‐Sabuncu et al., 2017; Fichtner et al., 2013; Koulakov et al., 2006; Papaleo et al., 2017, 2018), specifically, whether there are differences in properties across the fault that leave an imprint on seismic structure to mantle lithospheric depths.…”

Section: Introductionmentioning

confidence: 99%

Seismic Tomographic Imaging of the Eastern Mediterranean Mantle: Implications for Terminal‐Stage Subduction, the Uplift of Anatolia, and the Development of the North Anatolian Fault

Kounoudis

Bastow

Ogden

et al. 2020

Geochem Geophys Geosyst

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The Eastern Mediterranean captures the east‐west transition from active subduction of Earth's oldest oceanic lithosphere to continental collision, making it an ideal location to study terminal‐stage subduction. Asthenospheric‐ or subduction‐related processes are the main candidates for the region's ∼2 km uplift and Miocene volcanism; however, their relative importance is debated. To address these issues, we present new P and S wave relative arrival‐time tomographic models that reveal fast anomalies associated with an intact Aegean slab in the west, progressing to a fragmented, partially continental, Cyprean slab below central Anatolia. We resolve a gap between the Aegean and Cyprean slabs, and a horizontal tear in the Cyprean slab below the Central Anatolian Volcanic Province. Below eastern Anatolia, the completely detached “Bitlis” slab is characterized by fast wave speeds at ∼500 km depth. Assuming slab sinking rates mirror Arabia‐Anatolia convergence rates, the Bitlis slab's location indicates an Oligocene (∼26 Ma) break‐off. Results further reveal a strong velocity contrast across the North Anatolian Fault likely representing a 40–60 km decrease in lithospheric thickness from the Precambrian lithosphere north of the fault to a thinned Anatolian lithosphere in the south. Slow uppermost‐mantle wave speeds below active volcanoes in eastern Anatolia, and ratios of P to S wave relative traveltimes, indicate a thin lithosphere and melt contributions. Positive central and eastern Anatolian residual topography requires additional support from hot/buoyant asthenosphere to maintain the 1–2 km elevation in addition to an almost absent lithospheric mantle. Small‐scale fast velocity structures in the shallow mantle above the Bitlis slab may therefore be drips of Anatolian lithospheric mantle.

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“…A number of teleseismic studies have measured variations in V P / V S by jointly inverting P and S arrival time data sets (e.g., Hammond & Humphreys, ; Schmandt & Humphreys, ). A recent work by Papaleo et al () estimated V P / V S from teleseismic data that constrain relative rather than absolute velocities; for this approach to be successful, accurate estimates of the background P wave and S wave velocity structure are required. However, both P wave and S wave velocity models are often not available for the same region and when they are, limitations arising from the resolving power of the tomography contaminate R S,P estimates (e.g., Deschamps & Trampert, ).…”

Section: Introductionmentioning

confidence: 99%

Thermal Nature of Mantle Upwellings Below the Ibero‐Western Maghreb Region Inferred From Teleseismic Tomography

et al. 2019

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Independent models of P wave and S wave velocity anomalies in the mantle derived from seismic tomography help to distinguish thermal signatures from those of partial melt, volatiles, and compositional variations. Here we use seismic data from SW Europe and NW Africa, spanning the region between the Pyrenees and the Canaries, in order to obtain a new S‐SKS relative arrival‐time tomographic model of the upper mantle below Iberia, Western Morocco, and the Canaries. Similar to previous P wave tomographic results, the S wave model provides evidence for (1) subvertical upper‐mantle low‐velocity structures below the Canaries, Atlas Ranges, and Gibraltar Arc, which are interpreted as mantle upwellings fed by a common lower‐mantle source below the Canaries; and (2) two low‐velocity anomalies below the eastern Rif and Betics that we interpret as the result of the interaction between quasi‐toroidal mantle flow induced by the Gibraltar slab and the mantle upwelling behind it. The analysis of teleseismic P wave and S wave arrival‐time residuals and the conversion of the low‐velocity anomalies to temperature variations suggest that the upwellings in the upper mantle below the Canaries, Atlas Ranges, and Gibraltar Arc system may be solely thermal in nature, with temperature excesses in the range ~100–350 °C. Our results also indicate that local partial melting can be present at lithospheric depths, especially below the Atlas Ranges. The locations of thermal mantle upwellings are in good agreement with those of thinned lithosphere, moderate to high heat‐flow measurements, and recent magmatic activity at the surface.

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Constraints on North Anatolian Fault zone width in the crust and upper mantle from S-wave teleseismic tomography

Cited by 9 publications

References 47 publications

Structure of the northwestern North Anatolian Fault Zone imaged via teleseismic scattering tomography

Structure of the northwestern North Anatolian Fault Zone imaged via teleseismic scattering tomography

Seismic Tomographic Imaging of the Eastern Mediterranean Mantle: Implications for Terminal‐Stage Subduction, the Uplift of Anatolia, and the Development of the North Anatolian Fault

Thermal Nature of Mantle Upwellings Below the Ibero‐Western Maghreb Region Inferred From Teleseismic Tomography

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