Rates of crustal deformation in the North Aegean trough-North Anatolian fault deduced from seismicity

1991 ◽  
Vol 136 (4) ◽  
pp. 421-432 ◽  
Author(s):  
Anastasia A. Kiratzi
Keyword(s):  
Crustal Deformation ◽  
North Anatolian Fault ◽  
The North ◽  
North Aegean

Geodetic analysis of the tectonic crustal deformation pattern in the North Aegean Sea, Greece

2021 ◽  
Author(s):  
Ilias Lazos ◽  
Sotirios Sboras ◽  
Christos Pikridas ◽  
Spyros Pavlides ◽  
Alexandros Chatzipetros
Keyword(s):  
Crustal Deformation ◽  
Aegean Sea ◽  
Deformation Pattern ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea

Recent and active deformation in the North Evia domain, a diffuse plate boundary between Eurasia and Aegean plates in the Western termination of the North Anatolian Fault. 

2021 ◽  
Author(s):  
Fabien Caroir ◽  
Frank Chanier ◽  
Virginie Gaullier ◽  
Julien Bailleul ◽  
Agnès Maillard-Lenoir ◽  
...  
Keyword(s):  
Fault Zone ◽  
Plate Boundary ◽  
Fault Zones ◽  
North Anatolian Fault ◽  
Fault System ◽  
Eurasian Plate ◽  
Slip Rates ◽  
The North ◽  
South West ◽  
North Aegean

<p>The Anatolia-Aegean microplate is currently extruding toward the South and the South-West. This extrusion is classically attributed to the southward retreat of the Aegean subduction zone together with the northward displacement of the Arabian plate. The displacement of Aegean-Anatolian block relative to Eurasia is accommodated by dextral motion along the North Anatolian Fault (NAF), with current slip rates of about 20 mm/yr. The NAF is propagating westward within the North Aegean domain where it gets separated into two main branches, one of them bordering the North Aegean Trough (NAT). This particular context is responsible for dextral and normal stress regimes between the Aegean plate and the Eurasian plate. South-West of the NAT, there is no identified major faults in the continuity of the NAF major branch and the plate boundary deformation is apparently distributed within a wide domain. This area is characterised by slip rates of 20 to 25 mm/yr relative to Eurasian plate but also by clockwise rotation of about 10° since ca 4 Myr. It constitutes a major extensional area involving three large rift basins: the Corinth Gulf, the Almiros Basin and the Sperchios-North Evia Gulf. The latter develops in the axis of the western termination of the NAT, and is therefore a key area to understand the present-day dynamics and the evolution of deformation within this diffuse plate boundary area.</p><p>Our study is mainly based on new structural data from field analysis and from very high resolution seismic reflexion profiles (Sparker 50-300 Joules) acquired during the WATER survey in July-August 2017 onboard the R/V “Téthys II”, but also on existing data on recent to active tectonics (i.e. earthquakes distribution, focal mechanisms, GPS data, etc.). The results from our new marine data emphasize the structural organisation and the evolution of the deformation within the North Evia region, SW of the NAT.</p><p>The combination of our structural analysis (offshore and onshore data) with available data on active/recent deformation led us to define several structural domains within the North Evia region, at the western termination of the North Anatolian Fault. The North Evia Gulf shows four main fault zones, among them the Central Basin Fault Zone (CBFZ) which is obliquely cross-cutting the rift basin and represents the continuity of the onshore Kamena Vourla - Arkitsa Fault System (KVAFS). Other major fault zones, such as the Aedipsos Politika Fault System (APFS) and the Melouna Fault Zone (MFZ) played an important role in the rift initiation but evolved recently with a left-lateral strike-slip motion. Moreover, our seismic dataset allowed to identify several faults in the Skopelos Basin including a large NW-dipping fault which affects the bathymetry and shows an important total vertical offset (>300m). Finally, we propose an update of the deformation pattern in the North Evia region including two lineaments with dextral motion that extend southwestward the North Anatolian Fault system into the Oreoi Channel and the Skopelos Basin. Moreover, the North Evia Gulf domain is dominated by active N-S extension and sinistral reactivation of former large normal faults.</p>

Slip-deficit estimation with a 3D fault model of the North Anatolian Fault by using InSAR time series

2021 ◽  
Author(s):  
Alison Seidel ◽  
Henriette Sudhaus
Keyword(s):  
Time Series ◽  
Crustal Deformation ◽  
Time Series Data ◽  
Fault Model ◽  
North Anatolian Fault ◽  
Series Data ◽  
The North ◽  
Slip Deficit ◽  
Finite Fault ◽  
Finite Fault Model

<p>Crustal earthquakes are events of sudden stress release throug­h rock failure, for example as a consequence of continuous and long-term stress buildup at tectonic faults that eventually exceeds the strength of rock. Before failure, under increasing stress at a fault, the surrounding crust is slowly deforming. The amount and pattern of crustal deformation carries information about location and potential magnitude of future earthquakes.</p><p>Time series of space-borne interferometric Synthetic Aperture Radar (InSAR) data can be used to precisely measure the surface motion, which corresponds to the crustal deformation, in the radar line-of-sight and across large areas. These observations open the opportunity to study fault loading in terms of location, size of locked parts at faults and their slip deficit. Here we study the North Anatolian Fault (NAF), a major right-lateral strike-slip fault zone of about 1500 km length in the north of Turkey and we create its first large-scale 3D finite-fault model based on InSAR data.</p><p>We use the InSAR time series of data recorded by ESA’s Envisat SAR satellite between 2002 and 2010 (Hussain et al., 2018 and Walters et al., 2014).<!-- Das ist nicht ganz eindeutig formuliert. rigid motion darf nicht auf die InSAR Daten bezogen werden. --> We represent the fault with several vertical, planar fault segments that trace the NAF with reasonable resolution. The medium model is a layered half space with a viscoelastic lower crust and mantle. Several GNSS velocity measurements are used to apply a trend correction and calibrate the InSAR time series data to an Eurasia-fixed-reference frame. We use the plate motion difference of the Anatolian and the Eurasian plates calculated through an Euler pole to set up a back-slip finite-fault model. We then optimize the back-slip as the slip deficit, the width and the depth of the locked fault zone at each segment to achieve a good fit to the measured surface motion.</p><p>We find shallow locking depths and small slip deficits in the eastern and westernmost regions of the NAF, while the central part shows both deeper locking depths and larger slip deficits for the observation period. <!-- So wie es jetzt ist sind es zu viele Wörter, wenn man diesen erklär-Satz rausnehmen würde, würde es gerade so passen. Für die Erdbebenaktivität im Osten hab ich bis jetzt für den Zeitraum auch noch kein entsprechendes Paper gefunden, da suche ich aber noch. -->For both parameters the trends are in an overall agreement to earlier studies. There, InSAR-time series data have been used to calculate slip deficits at the North Anatolian fault with 2D models and/or assuming a homogeneous and purely elastic medium.<!-- Passt vom flow jetzt besser hier hin, denke ich. --> Local modeled differences therefore might be connected to differences in the modeling approaches, but also remain subject to further investigations and discussions.</p><p>Our model provides a very suitable basis for future time-dependent modeling of the slip deficit at the NAF that includes also more recent InSAR time series based on data from the Sentinel-1 radar satellite mission of ESA.</p>

Accelerating seismic crustal deformation in the North Aegean Trough, Greece

2002 ◽  
Vol 148 (2) ◽  
pp. 193-200 ◽  
Author(s):  
G. F. Karakaisis ◽  
C. B. Papazachos ◽  
A. S. Savvaidis ◽  
B. C. Papazachos
Keyword(s):  
Crustal Deformation ◽  
The North ◽  
North Aegean

scholarly journals Tsunamigenic potential of a Holocene submarine landslide along the North Anatolian Fault (North Aegean Sea, off Thasos Island): insights from numerical modeling

2018 ◽  
Author(s):  
Alexandre Janin ◽  
Mathieu Rodriguez ◽  
Dimitris Sakellariou ◽  
Vasilis Lykousis ◽  
Christian Gorini
Keyword(s):  
Tsunami Wave ◽  
Aegean Sea ◽  
Submarine Landslide ◽  
North Anatolian Fault ◽  
Potential Hazard ◽  
Submarine Landslides ◽  
The North ◽  
North Aegean ◽  
North Aegean Sea ◽  
Water Height

Abstract. The North Anatolian Fault in the northern Aegean Sea triggers frequent earthquakes of magnitude up to Mw ∼ 7. This seismicity can be a source of modest tsunamis for the surrounding coastlines with less than 50 cm height according to numerical modelling and analysis of tsunami deposits. However, other tsunami sources may be involved, like submarine landslides. We assess the severity of this potential hazard by performing numerical simulations of tsunami generation and propagation from a Holocene landslide (1.85 km3 in volume) identified off Thasos island. We use a model coupling the simulation of the submarine landslide, assimilated to a granular flow, to the propagation of the tsunami wave. The results of these simulations show that a tsunami wave of water height between 1.10 m and 1.65 m reaches the coastline at Alexandroupolis (58.000 inhabitants) one hour after the triggering of the landslide. In the same way, tsunamis waves of water height between 0.80 m and 2.00 m reach the coastline of the Athos peninsula 9 min after the triggering of the landslide. Landslide tsunamis should not be neglected as a potential source of tsunami in the area. Despite numerous earthquakes of Mw > 7 and strong detrital input (on the order of 30 cm ka−1), only a few Holocene landslides have been recognized so far, asking the question of the relationships between seismicity and landslide frequency in the area.

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