An aseismic slip transient on the North Anatolian Fault

Rousset, Baptiste; Jolivet, Romain; Simons, M.; Lasserre, Cécile; Riel, Bryan; Milillo, Pietro; Çakır, Ziyadin; Renard, François

doi:10.1002/2016gl068250

Cited by 89 publications

(125 citation statements)

References 49 publications

(75 reference statements)

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“…Our estimate for the average fault creep rate is similar to recent estimates by Karabacak et al [], Ozener et al [], Kaneko et al [], and Cetin et al [] who estimate average creep rates of 6–9 mm/yr, 7.6 ± 1, 9 mm/yr, and 8 ± 2 mm/yr, respectively. Our MAP solution for the depth extent of aseismic fault creep (9 km) is deeper than the 5 km estimated by Cetin et al [] and the 4 km estimated by Rousset et al []. However, our 95% confidence bound on this parameter is large (1–20 km).…”

Section: Discussioncontrasting

confidence: 52%

Interseismic strain accumulation across the central North Anatolian Fault from iteratively unwrapped InSAR measurements

et al. 2016

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The North Anatolian Fault (NAF) is a major tectonic feature in the Middle East and is the most active fault in Turkey. The central portion of the NAF is a region of Global Navigation Satellite Systems (GNSS) scarcity. Previous studies of interseismic deformation have focused on the aseismic creep near the town of Ismetpasa using radar data acquired in a single line‐of‐sight direction, requiring several modeling assumptions. We have measured interseismic deformation across the NAF using both ascending and descending data from the Envisat satellite mission acquired between 2003 and 2010. Rather than rejecting incorrectly unwrapped areas in the interferograms, we develop a new iterative unwrapping procedure for small baseline interferometric synthetic aperture radar (InSAR) processing that expands the spatial coverage. Our method corrects unwrapping errors iteratively and increases the robustness of the unwrapping procedure. We remove long wavelength trends from the InSAR data using GNSS observations and deconvolve the InSAR velocities into fault‐parallel motion. Profiles of fault‐parallel velocity reveal a systematic eastward decrease in fault slip rate from 30 mm/yr (25–34, 95% confidence interval (CI)) to 21 mm/yr (14–27, 95% CI) over a distance of ∼200 km. Direct offset measurements across the fault reveal fault creep along a ∼130 km section of the central NAF, with an average creep rate of 8 ± 2 mm/yr and a maximum creep rate of 14 ± 2 mm/yr located ∼30 km east of Ismetpasa. As fault creep is releasing only 30–40% of the long‐term strain in the shallow crust, the fault is still capable of producing large, damaging earthquakes in this region.

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Section: Discussioncontrasting

confidence: 52%

Interseismic strain accumulation across the central North Anatolian Fault from iteratively unwrapped InSAR measurements

et al. 2016

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“…Another issue is the possible occurrence of transient creep episodes separated by locking periods. Such behavior was already observed east of the Izmit and Düzce rupture zones where the shallow part of the NAF experienced a 1 month aseismic slip event in 2013 [ Rousset et al , ]. In the context of the Marmara Sea, such localized transient will be difficult to identify using only land‐based geodetic measurements.…”

Section: Discussionmentioning

confidence: 99%

Aseismic slip and seismogenic coupling in the Marmara Sea: What can we learn from onland geodesy?

Klein

Duputel

Masson

et al. 2017

Geophysical Research Letters

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Ever since the Mw7.4 Izmit earthquake in 1999, evaluation of seismic hazard associated with the last unbroken segments of the North Anatolian fault is capital. A strong controversy remains over whether Marmara fault segments are locked or are releasing strain aseismically. Using a Bayesian approach, we propose a preliminary probabilistic interseismic model constrained by published GPS data sets. The posterior mean model show that Ganos and Cinarcik segments are locked while creep is detected in the central portion of Marmara fault. Our analysis, however, reveals that creeping segments are associated with large model uncertainties, which mainly results from the sparsity of current geodetic observations. We then discuss how the GPS network can be improved to attain more reliable assessment of interseismic slip rates. With this purpose, we implement a network optimization procedure to identify the most favorable distribution of stations measuring strain accumulation in the Marmara Sea.

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“…A striking feature of the North Anatolian Fault is the existence of different segments that show differing slip behaviors indicative of differing mechanical behaviors. Some segments remain locked and are prone to major earthquakes [ Ambraseys , ; Stein et al ., ], while others display active aseismic or postseismic creep measured using radar interferometry in particular [ Kaneko et al ., ; Cetin et al ., ; Hussain et al ., ; Rousset et al ., ]. According to Kondo et al .…”

Section: Introductionmentioning

confidence: 99%

The implications of fault zone transformation on aseismic creep: Example of the North Anatolian Fault, Turkey

et al. 2017

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Aseismic creep is observed at surface along several segments of the North Anatolian right‐lateral active fault in Turkey, a major plate boundary between Eurasia and Anatolia. Identifying the mechanisms that control creep and their temporal and spatial change represents a major challenge for predicting the mechanical evolution of active faults, the interplay between creep and earthquakes, and the link between short‐term observations from geodesy and the long‐term fault zone evolution. We combine geological observations, laboratory analyses, and imaging techniques, shedding new light on the mechanism of fault creep along the North Anatolian Fault (NAF) and its time‐dependent change. A clear correlation is shown between shallow creep and near‐surface fault gouge composition: locked segments of the NAF are mostly composed of massive limestones without clay gouges, whereas creeping segments comprise clay gouges that contain low‐friction minerals. Such fault gouges appear to result from a progressive change of initial volcanic host rocks during their deformation. Anastomosing cleavage develops during the first stage of displacement, leading to layering, oblique at first and then subparallel to the fault, which accommodates part of the aseismic creep by pressure solution. Soluble minerals are dissolved, leading to passive concentration of phyllosilicates in the gouges where alteration transformations by fluid flow produce low friction minerals. At the same time damage zones are fractured and fractures are sealed by carbonates. As a result, these mineralogical and structural transformations weaken the gouge and strengthen the damage zone leading to the change from diffuse to localized seismic‐aseismic zones.

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An aseismic slip transient on the North Anatolian Fault

Cited by 89 publications

References 49 publications

Interseismic strain accumulation across the central North Anatolian Fault from iteratively unwrapped InSAR measurements

Interseismic strain accumulation across the central North Anatolian Fault from iteratively unwrapped InSAR measurements

Aseismic slip and seismogenic coupling in the Marmara Sea: What can we learn from onland geodesy?

The implications of fault zone transformation on aseismic creep: Example of the North Anatolian Fault, Turkey

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