Geomorphology, Geological Structure, Active Tectonics, and Basin Formation in the Aegean Sea

2021 ◽  
Author(s):  
D. Sakellariou ◽  
G. Rousakis ◽  
P. Drakopoulou ◽  
K. Tsampouraki-Kraounaki ◽  
I. Morfis ◽  
...  
Keyword(s):  
Active Tectonics ◽  
Aegean Sea ◽  
Geological Structure ◽  
Basin Formation

scholarly journals Morphotectonic Analysis along the Northern Margin of Samos Island, Related to the Seismic Activity of October 2020, Aegean Sea, Greece

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitrios Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  
Keyword(s):  
Fault Zone ◽  
Seismic Activity ◽  
Volcanic Rocks ◽  
Active Tectonics ◽  
Normal Fault ◽  
Aegean Sea ◽  
Northern Margin ◽  
The North ◽  
Eastern Aegean ◽  
Half Graben

On 30 October 2020, a strong earthquake of magnitude 7.0 occurred north of Samos Island at the Eastern Aegean Sea, whose earthquake mechanism corresponds to an E-W normal fault dipping to the north. During the aftershock period in December 2020, a hydrographic survey off the northern coastal margin of Samos Island was conducted onboard R/V NAFTILOS. The result was a detailed bathymetric map with 15 m grid interval and 50 m isobaths and a morphological slope map. The morphotectonic analysis showed the E-W fault zone running along the coastal zone with 30–50° of slope, forming a half-graben structure. Numerous landslides and canyons trending N-S, transversal to the main direction of the Samos coastline, are observed between 600 and 100 m water depth. The ENE-WSW oriented western Samos coastline forms the SE margin of the neighboring deeper Ikaria Basin. A hummocky relief was detected at the eastern margin of Samos Basin probably representing volcanic rocks. The active tectonics characterized by N-S extension is very different from the Neogene tectonics of Samos Island characterized by NE-SW compression. The mainshock and most of the aftershocks of the October 2020 seismic activity occur on the prolongation of the north dipping E-W fault zone at about 12 km depth.

Deep Structure and Active Tectonics of the South Aegean Volcanic Arc

Elements ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 153-158 ◽  
Author(s):  
Costas B. Papazachos
Keyword(s):  
Deep Structure ◽  
Active Tectonics ◽  
Aegean Sea ◽  
Low Velocity ◽  
Volcanic Arc ◽  
High Attenuation ◽  
Global Positioning ◽  
Back Arc ◽  
The Impact ◽  
Subducting Slab

The seismotectonic setting of the Aegean Sea, based on information from seismicity, neotectonics and global positioning system studies, is characterized by a sharp transition from a compressional outer arc to a complex back-arc, with an approximate north–south extension along the volcanic arc. Seismicity and 3-D tomography studies reveal the geometry of the subducting slab and image the low-velocity/high-attenuation mantle wedge at depths of 50–80 km beneath the volcanic arc where magma is generated. The 1956 Amorgos M7.5 earthquake and the impact from its seismic shaking and landslide-triggered tsunamis are discussed in the context of the regional seismotectonic setting.

Numerical Simulation on Forming Dynamics Mechanism and Stress State of Qianning Basin

2012 ◽  
Vol 226-228 ◽  
pp. 1458-1461
Author(s):  
Sheng Rui Su ◽  
Ying Zhang ◽  
Hu Jun He ◽  
Xiao Jian Wang
Keyword(s):  
Control Function ◽  
High Stress ◽  
Element Model ◽  
Tectonic Stress ◽  
Geological Structure ◽  
Rock Body ◽  
High Stress Concentration ◽  
Basin Formation ◽  
Fault Belt ◽  
Rock Mechanical Properties

Two-dimensional finite element model of Qianning basin was built on the basis of depth study on geological structure conditions and of rock mechanical properties in Qianning basin, tectonic stress field characteristics of Qianning fault belt and Qianning basin formation mechanism were inversed. The results show that: (1)A remarkable low stress region is come into being in the central part of Qianning basin, the low stress environment in the strike-slip fault zone has a very important control function for the basin formation. (2)in the rock bridge area of secondary fault belt sinistral right order, high stress concentration zone are formed, rock body subject to extrusion, which often forms pushing structure, the surface morphology appears landforms phenomenon such as surface uplift, drum kits etc.

scholarly journals Seismicity and active tectonics at Coloumbo Reef (Aegean Sea, Greece): Monitoring an active volcano at Santorini Volcanic Center using a temporary seismic network

2009 ◽  
Vol 465 (1-4) ◽  
pp. 136-149 ◽  
Author(s):  
I. Dimitriadis ◽  
E. Karagianni ◽  
D. Panagiotopoulos ◽  
C. Papazachos ◽  
P. Hatzidimitriou ◽  
...  
Keyword(s):  
Active Tectonics ◽  
Aegean Sea ◽  
Active Volcano ◽  
Seismic Network ◽  
Volcanic Center

scholarly journals Hydrochemical characteristics of the Gallikos River water, Prefecture of Kilkis, Greece

2013 ◽  
Vol 9 (3) ◽  
pp. 251-258
Keyword(s):  
Water Quality ◽  
River Water ◽  
River Basin ◽  
Major Ions ◽  
Groundwater Resources ◽  
Aegean Sea ◽  
Geological Structure ◽  
Quaternary Deposits ◽  
North Aegean Sea ◽  
Water Quality Deterioration

The Gallikos river basin is located in the northern part of Greece and discharges into the Thermaikos Gulf, North Aegean sea. Three main tributaries contribute to the river, the basin of which has a total areal extent of 930 km2. The basin of Gallikos river is formed of metamorphic rocks, limestones, Neogene and Quaternary deposits. Groundwater resources are mainly located within the carbonate rocks and the quaternary deposits. Water quality deterioration is documented based on the performed hydrochemical analyses of samples collected along the river course and its tributaries during the end of the wet and the dry seasons of year 2004. Results were correlated to the groundwater quality as this is reflected by analyses conducted on samples collected from wells adjacent to the river over the same periods. Samples were analyzed for major ions, nitrates, BOD5, COD, heavy metals and boron, whilst in situ measurements of pH, electrical conductivity and water temperature were performed. River water quality is related to the flow regime and is influenced by the geological structure, agricultural activities, as well as by untreated waste effluent that is discharged from villages and small industrial units that are scattered along the river basin.

Beachrock formation on the coast of Gökçeada Island and its relation to the active tectonics of the region, northern Aegean Sea, Turkey

2016 ◽  
Vol 401 ◽  
pp. 141-152 ◽  
Author(s):  
Mustafa Avcıoğlu ◽  
Erdinç Yiğitbaş ◽  
Ahmet Evren Erginal
Keyword(s):  
Active Tectonics ◽  
Aegean Sea ◽  
Northern Aegean Sea

scholarly journals A CONTRIBUTION TO THE GEOLOGICAL STRUCTURE OF CHIOS ISLAND, EASTERN AEGEAN SEA

2017 ◽  
Vol 43 (1) ◽  
pp. 379
Author(s):  
V. Tselepidis ◽  
Th. Rondoyanni
Keyword(s):  
Aegean Sea ◽  
Lower Triassic ◽  
Geological Structure ◽  
Eastern Aegean ◽  
Tectonic Contact ◽  
Paleozoic Rocks ◽  
Geological Units ◽  
Local Deposition ◽  
Tectonic Relationship ◽  
Eastern Aegean Sea

Τhe island of Chios, in the eastern Aegean Sea, is of great geological interest due to the outcrops of the oldest Paleozoic rocks of the Hellenides. Three main geological units of Paleozoic and Mesozoic age dominate, that have a tectonic relationship: the Autochthonous unit is overthrusted by the Parautochthonous unit, which in turn is overthrusted by the Allochthonous unit. In this work, new geological and tectonic data concerning the Autochthonous unit and especially its part of the Paleozoic - Mesozoic transition are presented and evaluated. Due to the rare outcrops of this transition and the lack of sufficient palaeontological data, there are various and contradictory opinions concerning its normal or discordant character. Based on our field data and lithostratigraphic correlations, we can draw the following main results: Considering the Autochthonous unit, the transition of the Paleozoic formations to the Mesozoic ones is characterized by an angular unconformity as well as by a basal conglomerate. In some places there is a tectonic contact between them, this of a thrust fault. The Lower Triassic formations of the Parautochthonous unit belong to the Autochthonous unit, since they present similar palaeogeographic conditions. Moreover, the presence of the “Hallstatt” limestones in the Autochthonous unit can be explained by their local deposition in lenticular form.

scholarly journals Seismic intensity assignments for the 2008 Andravida (NW Peloponnese, Greece) strike-slip event (June 8, Mw=6.4) based on the application of the Environmental Seismic Intensity scale (ESI 2007) and the European Macroseismic scale (EMS-98)

2014 ◽  
Vol 56 (6) ◽  
Author(s):  
Spyridon D. Mavroulis ◽  
Ioannis G. Fountoulis ◽  
Emmanuel N. Skourtsos ◽  
Efthymis L. Lekkas ◽  
Ioannis D. Papanikolaou
Keyword(s):  
Structural Damage ◽  
Surface Deformation ◽  
Active Tectonics ◽  
Geological Structure ◽  
Seismic Intensity ◽  
Strike Slip ◽  
Masonry Buildings ◽  
Small Surface ◽  
Geotechnical Characteristics ◽  
Slip Event

On June 8, 2008, a strike-slip earthquake (Mw=6.4) was generated NE of the Andravida town (NW Peloponnese, western Greece) due to the activation of the previously unknown western Achaia strike-slip fault zone (WAFZ). Extensive structural damage and earthquake environmental effects (EEE) were induced in the NW Peloponnese, offering the opportunity to test and compare the ESI 2007 and the EMS-98 intensity scales in a moderate strike-slip event. No primary EEE were induced, while secondary EEE including seismic fractures, liquefaction phenomena, slope movements and hydrological anomalies were widely observed covering an area of about 800 km<sup>2</sup>. The lack of primary effects and the relatively small surface deformation with respect to the earthquake magnitude is due to the thick Gavrovo flysch layer in the affected area that isolated and absorbed the subsurface deformation from the surface. According to the application of the EMS-98 scale, damage to masonry buildings ranged from grade 3 to 5, while damage in most of R/C buildings ranged from grade 1 to 3. A maximum ESI 2007 intensity VIII-IX is recorded, while the maximum EMS-98 intensity is IX. For all the sites where intensity VIII has been recorded the ESI 2007 and the EMS-98 agree, but for others the ESI 2007 intensities values are lower by one or two degrees than the corresponding EMS-98 ones, as it is clearly concluded from the comparison of the produced isoseismals. An exception to this rule is the Valmi village, where considerable structural damage occurs (IX<sub>EMS-98</sub>) along with the lack of significant EEE (V<sub>ESI 2007</sub>). This variability between the ESI 2007 and the EMS-98 intensity values is predominantly attributed to the vulnerability of old masonry buildings constructed with no seismic resistance design. Correlation of all existing data shows that the geological structure, the active tectonics, and the geotechnical characteristics of the alpine and post-alpine formations along with the construction type of buildings were of decisive importance in the damage and the EEE distribution.

Active tectonics and Quaternary basin formation along the Vienna Basin Transform fault

2005 ◽  
Vol 24 (3-4) ◽  
pp. 305-320 ◽  
Author(s):  
K DECKER ◽  
H PERESSON ◽  
R HINSCH
Keyword(s):  
Active Tectonics ◽  
Transform Fault ◽  
Vienna Basin ◽  
Basin Formation
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