Cyprus Arc Research Articles

The European Fault-Source Model 2020 (EFSM20): geologic input data for the European Seismic Hazard Model 2020

Abstract. Earthquake hazard analyses rely on seismogenic source models. These are designed in various fashions, such as point sources or area sources, but the most effective is the three-dimensional representation of geological faults. We here refer to such models as fault sources. This study presents the European Fault-Source Model 2020 (EFSM20), which was one of the primary input datasets of the recently released European Seismic Hazard Model 2020. The EFSM20 compilation was entirely based on reusable data from existing active fault regional compilations that were first blended and harmonized and then augmented by a set of derived parameters. These additional parameters were devised to enable users to formulate earthquake rate forecasts based on a seismic-moment balancing approach. EFSM20 considers two main categories of seismogenic faults: crustal faults and subduction systems, which include the subduction interface and intraslab faults. The compiled dataset covers an area from the Mid-Atlantic Ridge to the Caucasus and from northern Africa to Iceland. It includes 1248 crustal faults spanning a total length of ∼95 100 km and four subduction systems, namely the Gibraltar, Calabrian, Hellenic, and Cyprus arcs, for a total length of ∼2120 km. The model focuses on an area encompassing a buffer of 300 km around all European countries (except for Overseas Countries and Territories) and a maximum of 300 km depth for the subducting slabs. All the parameters required to develop a seismic source model for earthquake hazard analysis were determined for crustal faults and subduction systems. A statistical distribution of relevant seismotectonic parameters, such as faulting mechanisms, slip rates, moment rates, and prospective maximum magnitudes, is presented and discussed to address unsettled points in view of future updates and improvements. The dataset, identified by the DOI https://doi.org/10.13127/efsm20 (Basili et al., 2022), is distributed as machine-readable files using open standards (Open Geospatial Consortium).

Ductile Versus Brittle Tectonics in the Anatolian–Aegean–Balkan System

It is hypothesized that the present tectonic setting of the Anatolian, Aegean and Balkan regions has been deeply influenced by the different deformation styles of the inner and outer belts which constituted the Oligocene Tethyan system. Stressed by the Arabian indenter, this buoyant structure has undergone a westward escape and strong bending. The available evidence suggests that in the Plio–Pleistocene time frame, the inner metamorphic core mainly deformed without undergoing major fragmentations, whereas the orogenic belts which flanked that core (Pontides, Balkanides, Dinarides and Hellenides) behaved as mainly brittle structures, undergoing marked fractures and fragmentations. This view can plausibly explain the formation of the Eastern (Crete–Rhodes) and Western (Peloponnesus) Hellenic Arcs, the peculiar time-space features of the Cretan basins, the development of the Cyprus Arc, the North Aegean strike-slip fault system, the southward escapes of the Antalya and Peloponnesus wedges and the complex tectonic setting in the Balkan zone. These tectonic processes have mostly developed since the late Late Miocene, in response to the collision of the Tethyan belt with the Adriatic continental domain, which accelerated the southward bending of the Anatolian and Aegean sectors, at the expense of the Levantine and Ionian oceanic domains. The proposed interpretation may help us to understand the connection between the ongoing tectonic processes and the spatio-temporal distribution of major earthquakes, increasing the chances of estimating the long-term seismic hazard in the study area. In particular, it is suggested that seismic activity in the Serbo–Macedonian zone may be favored by the post-seismic relaxation that develops after seismic crises in the Epirus thrust front and inhibited/delayed by the activations of the North Anatolian fault system.

Investigation of the effects of Kahramanmaraş earthquake series on Cyprus Arc, Dead Sea fault, Hatay regions and stations close to two earthquakes epicenters

In various parts of the globe, there have been several earthquakes of a modest size. Monitoring the change of the points over time is a key component of typical techniques for extracting dynamic responses. This technique was unable to completely extract all of the earthquake’s dynamic properties. The GNSS precise point positioning (PPP) may be a useful tool for obtaining values of the point’s displacement that are more exact up to millimeters, which can help to overcome these flaws and evaluate the seismic wave of such earthquakes. Ultimately, PPP is a crucial tool for getting the precise observations. In this study, Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP) approach to analyze the station’s displacement components and the station’s heights in periods from the two Kahramanmaraş earthquakes. The earthquake sequences that occurred in Turkey’s Kahramanmaraş in 2023 is an example of complicated faulting brought on by interactions between three plates close to the Hatay Triple Junction (HTJ). While the relative plate movements in this area are minimal (usually less than 10 mm/year), even sluggish plate motion zones may nevertheless see earthquakes that are quite destructive. Due to the three-plate system’s unusual geometry, a number of large earthquakes with very varied fault orientations were active throughout this series. A 7.8-magnitude earthquake happened on February 6, 2023 in southern Turkey, close to Syria’s northern border. A magnitude 7.5 earthquake, situated about 95 kilometers to the southwest, was occurred nine hours after the first one. The first earthquake was as big as the most powerful one ever recorded there in 1939 and was the most catastrophic to strike earthquake-prone Turkey in more than 20 years. In this study, the effects of two earthquakes in Kahramanmaraş were investigated on the Cyprus Arc, the Dead Sea fault, Hatay and the points close to two earthquakes zone. In the obtained results, it was computed that the greatest horizontal displacement occurred at the HAT2 station with 68.97 cm.

Characterization of Micro-seismic Activity in Northern Cyprus Using Complexity and Corner Frequency Methods

Cyprus is an island country located in the eastern Mediterranean, to the south of Türkiye and the western of Syria and Lebanon, and is a popular tourist destination. Due to being surrounded by seas on all four sides, meticulous planning of rescue, assistance, and evacuation plans is necessary in the face of disasters such as earthquakes and tsunamis. Tectonically, the southern part of the island is controlled by the Cyprus Arc, while the northern part is dominated by the Kyrenia Range. The demand for raw materials for construction and industry is met through controlled quarry blasting operations carried out by open-pit quarry companies in the districts of Kyrenia and Nicosia. As a result, both natural and artificial seismic events occur in the region, and these quakes are documented in seismic catalogs by seismology centers. However, due to the low energy content of micro-seismic events and the inadequacy of seismic stations on the island, the source types of these seismic events can be misidentified in the catalogs. In this context, the study focuses on 122 seismic events with magnitudes between 0.9≤Ml≤2.7 that occurred in Northern Cyprus during the January 2018 - December 2021 period (4 years). The seismic events recorded by the station LFK, operated by Boğaziçi University Kandilli Observatory and Earthquake Research Institute Regional Earthquake-Tsunami Monitoring Center (KOERI-RETMC), were classified using Linear and Quadratic Discriminant Functions based on complexity and corner frequency methods. According to the results obtained, 10 of the 122 seismic events were identified as natural, and 96 were determined to be artificial, resulting in a general success rate of 86.89%. However, classification results for 16 seismic events were inconclusive with the methods used. As a result, more detailed secondary analyses should be conducted to accurately determine the source types of micro-seismic events, and the seismic catalogs should be updated accordingly.

Continued Convergence After the Occurrence of a Slab Break‐Off: The Case of the Cyprian Arc

AbstractThe detachment (i.e., break‐off) of down‐going subducting oceanic slabs is a major geodynamic event with far‐reaching consequences, one of which is the reduction of the slab pull force acting on the trailing plate. We investigate the motion of the Sinai Microplate where a recent (∼1 Myr ago) slab break‐off occurred along its sole converging plate boundary (Cyprian Arc) with the overriding Anatolia Microplate. Based on new bathymetric mapping, high‐resolution seismic reflection imaging, geodetic and earthquake data, we show that Sinai is actively moving in a northwest direction with respect to Nubia. Our results indicate that despite the recent slab break‐off, Sinai has and is still being pulled (or pushed) toward the overriding Anatolia Microplate. The continued convergence possibly occurs because of a persistent slab pull force, a suction force induced by the down‐going detached slab and/or by the upper mantle flow induced by the Afar Plume.

High-resolution co-seismic fault offsets of the 2023 Türkiye earthquake ruptures using satellite imagery

On February 6, 2023, southern Türkiye was struck by two large earthquakes at 01:17 UTC (Mw=7.8, Pazarcık, Kahramanmaraş) and 10:30 UTC (Mw = 7.6, Elbistan, Kahramanmaraş), causing severe damage at the complex junction of the Dead Sea Fault (DSF), the Cyprus Arc and the East Anatolian Fault Zone (EAFZ). The ruptures propagated along several known strands of the southwestern termination of the EAFZ, the main Pazarcık and Karasu valley faults, and the Çardak-Sürgü fault. Here we present the high-resolution mapping of the entire coseismic surface rupture and an estimate of the rupture width, total and on-fault offset, and diffuse deformation obtained a few days to three months after the two mainshocks. The mapping is derived from image correlation of Sentinel-2 optical satellite imagery and validated with offset measurements collected on the ground. We find that the ruptures extend over lengths of 310 km and 140 km for the Mw 7.8 and Mw 7.6 mainshocks, respectively. The maximum offsets reach 7.5 ± 0.8 m and 8.7 ± 0.8 m near the epicenters of the Mw 7.8 and Mw 7.6 events, respectively. We propose a segmentation of the two ruptures based on these observations, and further discuss the location of the potential supershear rupture. The use of optical image correlation, complemented by field investigations along earthquake faults, provides new insights into seismic hazard assessment.

Miocene to Quaternary geodynamic evolution of the southern section of the Burdur-Fethiye Shear Zone and its offshore continuation, eastern Mediterranean

The main interrelated structures of the eastern Mediterranean are shaped by the complex tectonic regimes including active subduction, uplift, and progressive counterclockwise rotation. The Hellenic Arc, the Anaximander Mountains, the Western Taurides, the extensional western Anatolian graben, the Burdur-Fethiye Shear Zone and the Rhodes Basin are these structures located in one of the most tectonically active regions. The Burdur-Fethiye Shear Zone is a 75- to 90- km wide and 300-km-long transtensional left-lateral shear zone developed during the formation of the Aegean back-arc extensional system and the thrusting of Western Taurides. In this study, fault kinematic analysis, and DEM and earthquake data characterize the tectonic controls of the southern section of the Burdur-Fethiye Shear Zone. The high-quality multibeam bathymetry data, their processing and interpretation with the onshore structures and an integrated interpretation with multichannel seismic profiles allowed the geodynamic evolution of the Burdur-Fethiye Shear Zone, Rhodes Basin and environs to be evaluated. Despite the heated debates regarding the presence of the zone, the latest offshore data reveals again that the continuation of the subduction transform edge propagator (STEP) fault between the Hellenic and Cyprus arcs comes into play as the Burdur-Fethiye Shear Zone on land.

Continued Convergence After the Occurrence of a Slab Break-off: The Case of the Cyprian Arc

Continued Convergence After the Occurrence of a Slab Break-off: The Case of the Cyprian Arc

Present-day strain accumulations and fault kinematics at the Hatay Triple Junction using new geodetic constraints

The East Anatolian Fault (EAF), Cyprus Arc and Dead Sea Fault (DSF) intersect at the Hatay Triple Junction (HTJ) in southern Turkey, which is a tectonically controversial zone among researchers. Although it is not as active as the North Anatolian Fault (NAF) or other segments on the EAF in terms of seismicity, the HTJ accumulates strain causing considerable seismic activity in the region. Prior to this study, the strain accumulations and kinematics of the HTJ have not been precisely investigated using such a dense GPS network comprising permanent GPS stations, Turkish National Fundamental GPS Network (TUTGA) and campaign sites. Here, the fault slip rates and locking depths were constrained in the vicinity of HTJ using a new velocity field and improved block modeling. As per the results of block modeling, the EAF and Karatas-Osmaniye Fault (KOF) are fully locked down to depths of 15 km and 7 km, respectively. Furthermore, the Karasu Fault (KF) has a fully locked seismogenic zone to 7 km depth with a similar slip distribution to the EAF. Our kinematic model suggests 9.2 mm/yr left-lateral strike-slip rate and 2.0–2.7 mm/yr thrust faulting slip rate at the southwest end of the EAF. The KF appears to have left-lateral strike-slip at the rates ranging 4.0–5.5 mm/yr, while contrarily it has no significant normal/reverse faulting component. In addition, the KOF accommodates left-lateral strike-slip of 3.3–4.5 mm/yr and extension with the rates of 1.8–2.7 mm/yr. The new constraints on the fault slip rates associated with the HTJ correspond to predictions for a probable large earthquake with possible magnitude ranging from 7.2 to 7.6 for the EAF segment and 6.7–7.2 for the KF and KOF segments.

Seismic Tomographic Modeling of the Crust and Upper Mantle beneath Israel and the Middle East: Improved Resolution through Optimized Model Parameterization

ABSTRACT Accurate regional seismic travel-time (RSTT) predictions rely on regional phases (e.g., Pg, Lg, Pn, Sn) to account for 3D effects in the crust and upper mantle that are not captured by 1D models traditionally used for real-time location. The RSTT prediction model accounts for regional-scale crust and upper mantle structure globally by incorporating regional seismic phases into its travel-time calculations. Previous versions of the RSTT model have used a constant grid cell size of 1°. To improve the tomographic accuracy of recovering velocity structure at regional scales, we perform data-driven grid refinement on the RSTT model down to a 0.125° grid (∼14 km) in pursuit of two main goals: (1) to test the limits of RSTT capability and accuracy of determined velocity structure through variable grid refinement and (2) to image smaller structures in Israel and the Middle East and illuminate upper mantle dynamics operating in this complex tectonic area. We investigate the effects of model parameterization as grid cell size decreases and the trade-offs between recovered velocity structures. Our final dataset includes 4751 events and 499 stations that recorded 79,344 Pn and 7489 Pg. The variable grid refinement method allows recovery of finer-scale velocity structures and reduces travel-time residuals in areas with the highest data coverage. At smaller grid cell sizes, longer paths need to be upweighted to stabilize the inversion. Results illuminate tectonic features undefined in coarser grid-size models; in particular, we observe mantle perturbations related to the subduction zone around the Cyprian arc and crustal anomalies near the Dead Sea fault and throughout the Anatolian plate.

Neotectonics of Turkey (Türkiye) and surrounding regions: a new perspective with block modelling

This paper aims to present a new neotectonic perspective concordant with the seismic activities in Turkey and surrounding regions. The neotectonic structures have been re-evaluated mainly by using focal mechanism solutions and high-resolution satellite (Google Earth) images. The Southeast Anatolian Wedge explains thrust/blind thrust and asymmetrical folding relationship in SE Turkey, Syria, and Northern Iraq. The neotectonic structures of the Turkish-Iranian Plateau are enlightened by the rhomboidal cell model which creates a base to determine multiple intersection points between the region-wide left- and right-lateral shear zones. The releasing stepover between the North Anatolian Fault Zone and Southeast Anatolian-Zagros Fault Zone plus their connections with the Northeast Anatolian Fault Zone and the East Anatolian Fault Zone are described in a more meaningful way with the Anatolian Diagonal concept. It also clarifies the role of left-lateral shear zone in the west-southwest movement of Anatolian plate and its relationship with the Aegean and Cyprus arcs. A neotectonic region under the influence of NW-SE contraction is determined between the North Anatolian, Eskişehir, and Kırıkkale-Erbaa fault zones in which the Elmadağ-Eldivan and Abdüsselam pinched crustal wedges and the Beypazarı Blind Thrust Zone are developed. A new route for the southern branch of the North Anatolian Fault Zone is determined between Bolu and Değirmenlik (Milos) Island in the Aegean Sea via Mudurnu, Bursa, Balıkesir, and İzmir. All main neotectonic structures mentioned in this paper are evaluated by the elastic dislocation modelling and new neotectonic provinces are suggested.

Palaeo-Tsunami Events on the Coasts of Cyprus

Cyprus has a long history of tsunami activity, as described in archaeological and geological records. Although the study area has experienced tsunamis in the past and constitutes an area threatened by this hazard both from the Cyprean arc and from the neighboring Hellenic arc, field research on tsunami evidence on the coastal zone of Cyprus still remains scarce. It is clear from the literature that large boulder accumulations are an important feature along the coasts of Cyprus, testifying to extreme events. A detailed field survey revealed that at various locations cited in the literature as hosting geomorphological evidence of past tsunamis, no such evidence was identified. It is likely that the high touristic activity that has been occurring on the coasts of Cyprus during the last 20 years may have affected tsunami indicators such as boulder accumulations. Tsunamis are unpredictable and infrequent but potentially large-impact natural disasters. The latest strong tsunami that caused damage to the Cypriot coast was centuries ago, when the population and economic growth and development at the Cypriot shoreline did not exist. Today, the coastal zone hosts a higher population as well as increasing touristic activity, highlighting the need for better preparedness, awareness raising and for tsunami-related risk reduction.

The Anatolian Diagonal: a broad left lateral shear zone between the North Anatolian Fault Zone and the Aegean / Cyprus Arcs

Recent detailed examination of the internal deformation of the Turkish-Iranian Plateau in the hinterland of Bitlis-Zagros Suture Zone, which is related to the collision of the Arabian and Eurasian plates, indicates multiple intersection points between the right- and left-lateral strike-slip structures explained by an inevitably broad left-lateral strike-slip shear zone, the Anatolian Diagonal. The faults bounding and internally deforming the Anatolian Diagonal were closely examined by using high-resolution satellite images, focal mechanism solutions of the earthquakes, and published seismic reflection data in the offshore areas. The Anatolian Diagonal is a NE-SW trending left-lateral shear zone having a 170 km width between the Central Anatolian and the East Anatolian fault zones and an 850 km length between Erzincan and the Cyprus Arc. It has at least four intersection points with the right-lateral North Anatolian Fault Zone and the Southeast Anatolian-Zagros Fault Zone. As the offshore continuation of the Ecemiş-Deliler Fault of the Anatolian Diagonal, the Biruni Fault reaches the Cyprus Arc and Piri Reis (Mediterranean) Ridge Front west of Cyprus. This structure creates a restraining stepover with the left-lateral Antalya-Kekova Fault Zone and causes NW-SE trending thrusts of the Florence Rise and Antalya Thrust in the Antalya Basin. There is another restraining stepover between the Antalya-Kekova Fault Zone and the Pliny-Strabo Fault Zone, where the thrust-controlled northern margin of Rhodes basin developed. In this neotectonic framework, there is no need for the existence of the highly-debated left-lateral Fethiye-Burdur Fault Zone as an onshore continuation of the Pliny and Strabo faults. In fact, the westerly motion of the Anatolian plate is accommodated by the left-lateral Anatolian Diagonal Shear Zone, Antalya-Kekova Fault Zone and Pliny-Strabo Fault Zone together with the right-lateral North Anatolian Fault Zone.

Imaging the tectonic components under the Eastern Mediterranean and Black Sea with gravity (satellite) data

Tectonic structures in the Black Sea and the Levantine Sea were mapped using satellite gravity data. The relationship between Antalya and Cyprus arcs is revealed by the deformation traces of the arc formation. The Cyprus arc which over the slice that disappears from the South of the Anaximander seamounts to the Northeast, can traceable at the western end of the Antalya Bay. The distinction of western and eastern basins in the Black Sea is also mapped. Due to the low spatial resolution, additional studies with higher resolution are required.

The assessment of local site effects and dynamic behaviour in Nicosia, Cyprus

Single-station microtremor measurements were conducted to investigate earthquake and soil behaviour for the first time in Nicosia, Cyprus. Cyprus is located in a tectonically complex area in the Eastern Mediterranean where three plates meet. The study area was chosen to cover the areas to be opened for new development. Nicosia, the capital of Cyprus, is also the island's most important cultural, industrial, commercial, and transportation centre. The study creates base maps for the soil to assess earthquake resistance crucial for construction. Microtremor Method was applied at 100 stations and the Multi-Channel Analysis of Surface Waves (MASW) method was used at 52 stations. Also, RefractionMicrotremor (Re-Mi) and L-Shaped Spatial Autocorrelation (L-SPAC) methods were carried out at 17 stations to substantiate the research. The results of the microtremor method indicate that the predominant soil period values have an average of 1 second and pre-dominant peak period values are generally found between 0.1 to 5 s at the study area. Peak amplitude values are observed between 1 and 2.4. The Vulnerability Index Parameter (Kg) exceeded 20 at the central and the southern stations, and Kg values change between 7 and 54 units. The Kg values were found to be higher than 20 in soils where shear wave velocity is lower than 760 m/s. At the same time, the values of the predominant peak period were greater than 1 second. Cyprus is located in the Alpine Himalayan earthquake zone. The Cyprus Arc is known as the main seismic source of the island, It constitutes the tectonic border among African and Eurasian lithospheric plates in the region. During an earthquake in Nicosia, seismic waves will be amplified by an average of 1.5 times and soil deformation will occur due to the exceeding elastic limits. The results provided important insight into soil behaviour and indicated its reactions in a potential earthquake.

A New Look at the Nature of the Cyprus Arc and Sinai Plate Based on the Wide-Angle Seismic Data of the USSR Academy of Sciences

A New Look at the Nature of the Cyprus Arc and Sinai Plate Based on the Wide-Angle Seismic Data of the USSR Academy of Sciences

The May 11 Paphos, Cyprus, earthquake: implications for stress regime and tsunami modelling for the Eastern Mediterranean shorelines

The paper deals with the analysis of the propagation, heights, and arrival times of a tsunami that may occur on the coastal areas of Cyprus and Eastern Mediterranean in the case of an earthquake in southern Cyprus. Following a review of the seismic risk and historical earthquakes which occurred in southern Cyprus, it was concluded that this region may be subject to high vulnerability if a tsunami occurs. A study was conducted on the numerical modelling of a possible tsunami generated by movement along the fault of the 1222 Paphos earthquake. The region where the earthquake occurred can be attributed to the Cyprian Arc in the southwest of Cyprus. This arc is one of the most active seismic zones in the Mediterranean, which has led to the occurrence of earthquakes from submerged seismogenic sources. A methodology is used to simulate tsunami wave propagation for the Eastern Mediterranean coastal areas which requires the initial wave due to fault parameters as well as the bathymetry data. The GEBCO30 bathymetry data are used which have a grid spacing of 0.30 arc min. The fault parameters are deduced from the maximum stress directions and source geometry of the region from the moment tensor solutions derived from analyzing of earthquake waveforms. The numerical tsunami propagation model was performed by using SWAN code. The simulated highest tsunami heights were 4.02 m in Kouklia (Cyprus); 2.85 m in Paphos Ktima (Cyprus); 2.58 in Episkopi (Cyprus); 2.06 in Peyia (Cyprus); 1.76 in Yennadhi, Rhodes (Greece); 1.53 in Burg Migheizil (Egypt); 1.46 m in Tarabulus (Lebanon); 1.39 m in Bur Said (Egypt); 1.28 in Al-Burj (Egypt); and 0.60 in Mugla-Aksaz (Turkey). The results of the model outline the extent of the tsunami waves of damaging size, but destructive event in the region.

Evaluation of seismic hazard with probabilistic approach for Antakya Province (Turkey)

Antakya province is tectonically affected by Dead Sea and East Anatolian faults and the Cyprus arc. Although there had been major and devastating earthquakes in the historical period, the fact that there is no major earthquake in the instrumental period increases the risk of seismic hazard of the region. In this study, it is aimed to perform a probabilistic seismic hazard analysis application for Antakya province, Turkey. For this purpose, the earthquakes (Mw ≥ 4) which occurred between 1900 and 2017 were used. Nine seismic source zones that could affect the Antakya province were identified and the seismic hazard parameters calculated for each zone. Peak ground acceleration (PGA) values that can occur in a possible earthquake were obtained according to a recurrence period of 475 yrs by using two different attenuation relationships and presented with iso-acceleration maps. The calculated PGA values in the study area are found as between 0.32 and 0.57 g for both attenuation relationships. The areas located on the north of Kirikhan district have the highest risk of seismic hazard in the study area according to determined PGA values.

New insights on the Neogene tectonic evolution of the Aksu Basin (SE Turkey) from the Anisotropy of Magnetic Susceptibility (AMS) and paleostress data

The junction between the Aegean and Cyprus arc in the southern Turkey forms a triangular-shaped morphological structure so-called Isparta Angle (IA). In Neogene time, the inner part of the Isparta Angle became overlain by sedimentary basins including Manavgat, Köprüçay and Aksu, characterized by marine clastics and carbonates.Aksu Basin, one of these marine basins, provides geological records about the Neogene crustal deformation and stress field in the Eastern Mediterranean region. Therefore, we kinematically assess if and when tectonic stress fields affected the Aksu basin in early Miocene to recent times. For this purpose, Anisotropy of Magnetic Susceptibility (AMS) data (AMS) of cored samples and fault-slip data from the brittle mesoscopic faults were collected. The ~490 oriented samples for Anisotropy of Magnetic Susceptibility measurements were analyzed and two different maximum magnetic lineation's directions are recognized; 1) N–S magnetic lineation in Pliocene and 2) from N–S to NW-SE magnetic lineation in the Miocene. The results inferred from more than 1000 fault-slip data collected from 83 different sites combined with AMS results demonstrate that the Aksu Basin developed under four different tectonic phases; 1) ~E-W extensional phase (related to basin formation), 2) ~N–S compressional (Lycian) phase, 3) ~(N)E-(S)W compressional (Aksu) phase and 4) N–S extensional (Recent) phase.

Tectonic characteristics of the Eratosthenes Seamount and its periphery: Implications for evolution of the eastern Mediterranean

A comprehensive tectonic analysis of the Eratosthenes Seamount (ESM) and its surrounding domains covered by our seismic data, contributes to better understanding of the evolution of the eastern Mediterranean. Tectonic origins of the ESM and the Zohr-like sub-Messinian salt highs between the ESM and the Nile delta are both continental fragments detached from the African-Arabian plate. These continental fragments form a NE-SW striking tectonic belt acting as the western margin of the Levant basin. After the Neotethyan rift, isolated carbonate platforms grew on these continental fragments and existed until the Miocene with alternations of shallow-water and deep-water carbonates caused by sea-level variation in the eastern Mediterranean. The subduction beneath the Cyprus arc beginning in the Early Miocene triggered onset of tectonic inversion of the deep-water area of the eastern Mediterranean. The ESM shielded the Zohr-like platforms from deforming by assimilating compressional stress from the Miocene subduction and the Messinian-present collision through its own folding, which led to tectonic evolutionary discrepancy between the Eratosthenes and the Zohr-like platforms since the Early Miocene. In addition, syn-sedimentary folding deformations related to the subduction were recognized in the southern Levant basin, the Herodotus eastern sub-basin, and the Cyprus arc. These deformations were all intense in the Early Miocene, attenuated gradually in the Middle and Late Miocene, and terminated at the very beginning of the Messinian. The weakening of these deformations could be associated with an increase in the subduction angle which also induced the development of the Mid-Late Miocene normal faults in the northern Levant basin. The initial African–Eurasian collision in the Messinian terminated these subduction-related deformations. Finally, we proposed a new evolutionary model of the deep-water area of the eastern Mediterranean, consisting of four stages, i.e. the Neotethyan rift stage from the Late Permian to the Early Jurassic, the post-rift tectonic stability stage from the Middle Jurassic Bajocian to the Oligocene, the subduction-related compression stage during the Miocene, and the collision-related compression-transpression stage from the Messinian to the present.