scholarly journals LATE QUATERNARY AND HOLOCENE FAULTS OF THE NORTHERN GULF OF CORINTH RIFT, CENTRAL GREECE

2017 ◽  
Vol 50 (1) ◽  
pp. 164 ◽  
Author(s):  
S. Valkaniotis ◽  
S. Pavlides
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Geological Mapping ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Central Greece ◽  
The North ◽  
Gulf Of Corinth ◽  
Area Of Study

New results for the recent tectonic activity in the northern part of the Gulf of Corinth rift are presented. Geological mapping and morphotectonic study re populate the area of study with numerous active and possible active faults. The area is dominated by individual and segmented normal faults along with major structures like Marathias and Delphi-Arachova faults. The results are in accordance with recent studies that reveal a more complex and wider structure of Corinth Rift to the north.

scholarly journals IDENTIFYING FAULT ACTIVITY IN THE CENTRAL EVOIKOS GULF (GREECE)

2018 ◽  
Vol 40 (1) ◽  
pp. 439 ◽  
Author(s):  
Th. Rondoyanni ◽  
D. Galanakis ◽  
Ch. Georgiou ◽  
I. Baskoutas
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Point Of View ◽  
Geological Mapping ◽  
Normal Faults ◽  
Geophysical Research ◽  
Alluvial Deposits ◽  
Moderate Seismicity ◽  
Limestone Bedrock ◽  
Topographic Relief

Geological mapping on a 1:5.000 scale and a tectonic analysis in the wider Chalkida region of the Island of Evia and the adjacent Drossia area of Central Greece, have allowed the identification of a number of active and potentially active normal faults. These faults have been formed or reactivated during the Late Quaternary, since they affect Pleistocene brackish and terrestrial deposits. Some of the faults affect the contact of the limestone bedrock with the Quaternary formations, presenting characteristic polished surfaces. The faults, in places covered by the alluvial deposits of the Chalkida plain, are also detected by geophysical research. Among the identified faults, the most important are considered the Aghios Minas- Chalkida, the Avlida and the Lefkadi active faults. The first one extends from Drossia to the Chalkida area, crossing the sea straights, and has an ENE-WSW direction and a south dip. The other two, are parallel antithetic faults oriented WNW-ESE, and bound the South Evoikos Gulf on the Greek mainland and the Evia Island respectively. The mapping and evaluation of active faults in this region of moderate seismicity, with low topographic relief and consequent absence of morphotectonic features, is especially important from a seismic hazard point of view.

scholarly journals Structural cross sections through the Corinth-Patras detachment fault-system in Northern Peloponnesus (Aegean Arc, Greece)

2001 ◽  
Vol 34 (1) ◽  
pp. 235 ◽  
Author(s):  
N. FLOTTÉ ◽  
D. SOREL
Keyword(s):  
Cross Sections ◽  
Detachment Fault ◽  
Fault System ◽  
Normal Faults ◽  
Field Observations ◽  
Structural Mapping ◽  
The North ◽  
Gulf Of Corinth ◽  
Aegean Arc

Structural mapping in northern Peloponnesus reveals the emergence of an E-W striking, more than 70km long, low angle detachment fault dipping to the north beneath the Gulf of Corinth. This paper describes four north-south structural cross-sections in northern Peloponnesus. Structural and sedimentological field observations show that in the studied area the normal faults of northern Peloponnesus branch at depth on this major low angle north-dipping brittle detachment. The southern part of the detachment and the related normal faults are now inactive. To the north, the active Helike and Aigion normal faults are connected at depth with the seismically active northern part of the detachment beneath the Gulf of Corinth.

scholarly journals Topographic Anaglyphs from Detailed Digital Elevation Models Covering Inland and Seafloor for the Tectonic Geomorphology Studies in and around Yoron Island, Ryukyu Arc, Japan

Geosciences ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 363 ◽  
Author(s):  
Hideaki Goto ◽  
Kohsaku Arai ◽  
Taichi Sato
Keyword(s):  
Late Quaternary ◽  
Active Faults ◽  
Aerial Photographs ◽  
Stress Axis ◽  
Tectonic Geomorphology ◽  
Surface Model ◽  
The North ◽  
Digital Elevation ◽  
Ryukyu Arc ◽  
Island Shelf

Anaglyphs produced using a digital elevation model (DEM) are effective to identify the characteristic tectono–geomorphic features. The objective of this study is to reinvestigate the tectonic geomorphology and to present novel tectonic maps of the late Quaternary in and around the Yoron island based on the interpretation of extensive topographical anaglyphs along the map areas that cover the inland and seafloor. Vintage aerial photographs are used to produce the 3-m mesh inland digital surface model (DSM); further, the 0.6-s to 2-s-mesh seafloor DEM is processed using the cloud point data generated through previous surveys. Thus, we identify anticlinal deformation on both the Pleistocene marine terrace and the seafloor to the north of the island. The deformation axis extends in a line and is parallel to the general trend of the island shelf. The Tsujimiya fault cuts the marine terraces, which extend to the Yoron basin’s seafloor. If we assume that the horizontal compressive stress axis is perpendicular to the island shelf, these properties can easily explain the distribution and style of the active faults and deformation. This study presents an effective methodology to understand the island arc tectonics, especially in case of small isolated islands.

scholarly journals Recent active faults in Belgian Ardenne revealed in Rochefort Karstic network (Namur Province, Belgium)

2001 ◽  
Vol 80 (3-4) ◽  
pp. 297-304 ◽  
Author(s):  
S. Vandycke ◽  
Y. Quinif
Keyword(s):  
Stress Field ◽  
Active Faults ◽  
Ground Surface ◽  
Local Stress ◽  
Tectonic Activity ◽  
Normal Faults ◽  
Regional Stress ◽  
Bedding Planes ◽  
Local Modification ◽  
A Minor

AbstractThis paper presents observations of recent faulting activity in the karstic network of the Rochefort Cave (Namur Province, Belgium, Europe). The principal recent tectonic features are bedding planes reactivated as normal faults, neo-formatted normal faults in calcite flowstone, fresh scaling, extensional features, fallen blocks and displacement of karstic tube. The seismo-tectonic aspect is expanded by the presence of fallen blocks where normally the cavity must be very stable and in equilibrium. Three main N 070° fault planes and a minor one affect, at a decimetre scale, the karst features and morphology. The faults are still active because recent fresh scaling and fallen blocks are observable. The breaking of Holocene soda straw stalactites and displacements of artificial features observed since the beginning of the tourist activity, in the last century, also suggest very recent reactivation of these faults. This recent faulting can be correlated to present-day tectonic activity, already evidenced by earthquakes in the neighbouring area. Therefore, karstic caves are favourable sites for the observation and the quantification of recent tectonic activity because they constitute a 3-D framework, protected from erosion. Fault planes with this recent faulting present slickensides. Thus a quantitative analysis in term of stress inversion, with the help of striated faults, has permitted to reconstruct the stress tensor responsible for the brittle deformation. The principal NW-SE extension (σ3 horizontal) is nearly perpendicular to that of the present regional stress as illustrated by the analysis of the last strong regional earthquake (Roermond, The Netherlands) in 1992. During the Meso-Cenozoic, the main stress tectonics recorded in this part of the European platform is similar to the present one with a NE-SW direction of extension.The discrepancy between the regional stress field and the local stress in the Rochefort cave can be the result of the inversion of the σ2 and σ3 axes of the stress ellipsoid due to its symmetry or of a local modification at the ground surface of the crustal stress field as it has been already observed in active zones.

Faulting in Mars Polar Layered deposits modeled by HCA method

2020 ◽  
Author(s):  
Paola Cianfarra ◽  
Costanza Rossi ◽  
Francesco Salvini ◽  
Laura Crispini
Keyword(s):  
Cross Section ◽  
Hydrothermal Activity ◽  
Geological Mapping ◽  
Normal Faults ◽  
Natural Material ◽  
Shallow Subsurface ◽  
Ice Caps ◽  
The North ◽  
Wide Range ◽  
Polar Layered Deposits

<p>The polar layered deposits (PLD) of Mars constitute the water ice stratigraphy of polar spiral troughs up to several kilometers thick (Phillips et al., 2011; Smith et al. 2015). PLD cross section profiles from the Shallow Subsurface Radar (SHARAD) instrument on NASA’s Mars Reconnaissance Orbiter, show the presence of internal discontinuities within these layers (Foss et al., 2017; Putzig et al., 2017). The mechanisms responsible for these deformations are still an open issue (Guallini et al., 2017) and this work represents the contribution of stress-related deformations. Layered ice is simulated by a mesh of cells within a HCA grid build replicating the physical properties and preserving volumes following balanced cross-section principles. Three major types of link exist among adjacent cells: 1. intra-layer relations link cells belonging to the same layer; 2. inter-layer relations regulate the relationships among adjacent layers; 3. discontinuity relations correspond to the presence of ruptures such as faults (Salvini et al., 2001). The HCA method allows to replicate the natural material anisotropies, such as rocks and ice sheet internal layering, and to simulate complex tectonic evolutionary paths (Cianfarra and Salvini, 2016; Cianfarra and Maggi, 2017). The models allow simulating the kinematics of the internal architecture of the layered deposits from both the north and the south Martian ice caps. In particular the observed stratigraphy (geometries and thickness of the ice layers) is replicated as resulting from the relative, normal movement among blocks separated by listric shaped normal faults and minor inversions.</p><p>The used HCA numerical methodology revealed an effective tool to support planetary geological mapping and 3D subsurface geological reconstructions. Through the integration of a net of spatially distributed along- and across- strike (balanced) sections it is possible to simulate the 4D (3D plus time) geological evolution of buried and/or topographic structures. Results have a wide range of applications including the optimal selection of landing sites for scheduled and future planetary exploration missions, as well as unravelling the geological and structural setting of enigmatic features on the planetary surfaces affected, for example, by salt tectonism, volcano-tectonics, tectonically-related hydrothermal activity, fluid storage and release, and ice tectonics.</p>

From Corinth gulf extension to Ionian subduction/collision (W. Greece): micro-seismicity survey to constrain local tectonics and regional geodynamics

2020 ◽  
Author(s):  
Valentine Lefils ◽  
Alexis Rigo ◽  
Efthimios Sokos
Keyword(s):  
Seismic Velocity ◽  
Deformation Mode ◽  
Velocity Model ◽  
Fault System ◽  
Normal Faults ◽  
Corinth Gulf ◽  
National Network ◽  
The North ◽  
Gulf Of Corinth ◽  
Seismological Network

<p>The North-Eastern zone of the Gulf of Corinth in Greece is characterized by the rotation of a micro-plate in formation. The Island Akarnanian Block (IAB) have been progressively individualized since the Pleistocene (less than ~ 1.5 My ago). This micro-plate is the result of a larger-scale tectonic context with, on one side the N-S extension of the Gulf of Corinth to the East, and on the other side the Hellenic subduction to the South and the Apulian collision to the West. To the Northeast, the IAB micro-plate is bounded by a large North-South sinistral strike-slip fault system, the Katouna-Stamna Fault (KSF) and by several normal faults. To the North, normal faults reach the limit between Apulian and Eurasian plates and to the East, they form the East-West graben of Trichonis lake.</p><p>Although the structures and dynamics behind the Gulf of Corinth extension are today relatively known, nevertheless, the set of faults linking the Gulf of Corinth to the Western subduction structures remain poorly studied. The seismicity recorded by the Greek national network shows discrepancies regarding to the faults mapped on the surface.</p><p>At the end of 2015, a new micro-seismicity campaign started with the deployment of a temporary seismological network in an area ranging from the Gulf of Patras to the Amvrakikos Gulf toward the North. This network includes 17 seismic stations, recording continuously, added to the permanent stations of the Corinth Rift Laboratory (CRL) and of the Hellenic Unified Seismic Network (HUSN).</p><p>The analysis of the seismological records is still in process for the 2016 and 2017 years. Our study consists first in picking the <em>P</em>- and <em>S</em>- waves, and then to precisely localize the seismic events recorded by our temporary seismological network combined with the permanent ones. We will present here the event location map obtained for the 2016-2017 period, a new seismic velocity model, and focal mechanisms. The seismic activity including thousands of events, is characterized by the presence of numerous clusters of few days to few weeks duration. The clusters are analysed in detail by relative relocations in order to appraise their physical processes and their implications in the fault activity. We will discuss the deformation mode of the region and build a seismotectonic model consistent with the regional geodynamics and observations.</p>

scholarly journals The Subsurface Geology and Landscape Evolution of the Volturno Coastal Plain, Italy: Interplay between Tectonics and Sea-Level Changes during the Quaternary

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3386
Author(s):  
Giuseppe Corrado ◽  
Sabrina Amodio ◽  
Pietro P. C. Aucelli ◽  
Gerardo Pappone ◽  
Marcello Schiattarella
Keyword(s):  
Cross Sections ◽  
Coastal Plain ◽  
Late Quaternary ◽  
Slip Rate ◽  
Tectonic Activity ◽  
Paleoenvironmental Reconstruction ◽  
Sea Level Changes ◽  
Plan View ◽  
North West ◽  
The North

The Volturno alluvial-coastal plain is a relevant feature of the Tyrrhenian side of southern Italy. Its plan-view squared shape is due to Pliocene-Quaternary block-faulting of the western flank of the south-Apennines chain. On the basis of the stratigraphic analysis of almost 700 borehole logs and new geomorphological survey, an accurate paleoenvironmental reconstruction before and after the Campania Ignimbrite (CI; about 40 ky) eruption is here presented. Tectonics and eustatic forcing have been both taken into account to completely picture the evolution of the coastal plain during Late Quaternary times. The upper Pleistocene-Holocene infill of the Volturno plain has been here re-organized in a new stratigraphic framework, which includes seven depositional units. Structural analysis showed that two sets of faults displaced the CI, so accounting for recent tectonic activity. Yet Late Quaternary tectonics is rather mild, as evidenced by the decametric vertical separations operated by those faults. The average slip rate, which would represent the tectonic subsidence rate of the plain, is about 0.5 mm/year. A grid of cross sections shows the stratigraphic architecture which resulted from interactions among eustatic changes, tectonics and sedimentary input variations. On the basis of boreholes analysis, the trend of the CI roof was reconstructed. An asymmetrical shape of its ancient morphology—with a steeper slope toward the north-west border—and the lack of coincidence between the present course of the Volturno River and the main buried bedrock incision, are significant achievements of this study. Finally, the morpho-evolutionary path of the Volturno plain has been discussed.

The evolution of the Lansarine–Baouala salt canopy in the North African Cretaceous passive margin in Tunisia

2013 ◽  
Vol 150 (5) ◽  
pp. 835-861 ◽  
Author(s):  
AMARA MASROUHI ◽  
OLIVIER BELLIER ◽  
HEMIN KOYI ◽  
JEAN-MARIE VILA ◽  
MOHAMED GHANMI
Keyword(s):  
Geological Mapping ◽  
Passive Margin ◽  
Normal Faults ◽  
North African ◽  
The North ◽  
Extensional Tectonic ◽  
Two Factors ◽  
Salt Structure ◽  
Differential Sedimentation ◽  
Cretaceous Period

AbstractDetailed geological mapping, dating, and gravimetric and seismic data are used to interpret the Lansarine–Baouala salt structure (North Tunisia) as a salt canopy emplaced during the Cretaceous Period. The extensional tectonic regime related to the Cretaceous continental margin offered at least two factors that encouraged buried Triassic salt to extrude onto the sea floor and flow downslope: (i) extension induced normal faults that provided routes to the surface, and led to the formation of sub-marine slopes along which salt could flow; (ii) this structural setting led to differential sedimentation and consequently differential loading as a mechanism for salt movement. The present 40-km-long Lansarine–Baouala salt structure with its unique mass of allochthonous Triassic salt at surface was fed from at least four stems. The salt structure is recognized as one of the few examples worldwide of a subaerial salt canopy due to the coalescence of submarine sheets of Triassic salt extruded in Cretaceous times.

Design and implementation of the seismotectonic Atlas of Greece v1.0

2020 ◽  
Author(s):  
Ioannis Kassaras ◽  
Vasilis Kapetanidis ◽  
Athanassios Ganas ◽  
Andreas Tzanis ◽  
Panayotis Papadimitriou ◽  
...  
Keyword(s):  
Crustal Deformation ◽  
Eastern Mediterranean ◽  
Active Faults ◽  
Active Tectonics ◽  
Geological Mapping ◽  
Geospatial Information ◽  
African Plate ◽  
Digital Version ◽  
Gulf Of Corinth ◽  
Of Greece

<p>Knowledge of the present-day relationships between earthquakes, active tectonics, and crustal deformation is a key for understanding the geodynamics, ongoing surface processes (i.e. erosion, sedimentation, etc.) and is also essential for the risk assessment and management of geo-reservoirs for energy and waste.</p><p>Greece is characterized by the most tectonically active regime in the eastern Mediterranean, involving (a) intense crustal deformation and thickening, with an uplift rate of a few mm/yr along the Hellenic Arc due to accretion of sediments of the African plate beneath the overriding Aegean plate, (b) wide-spread extension in the back-arc region (for example in the Gulf of Corinth) due to retreat of the African slab and (c) significant strike-slip motions due to offset between oceanic-continental subduction in the west and the westward propagation of Anatolia in the east. Study of the complexity of the contemporary Greek tectonics has been the subject of intense efforts of our working group during the last decade, employing multidisciplinary state-of-the-art methodologies regarding geological mapping, seismological and geodetic surveying and numerical analyses at various scales. The products of these studies are the pieces of a puzzle that we aim to merge with existing data (topography, bathymetry, land-use, etc) in order to compose the digital version of the modern Seismotectonic Atlas of Greece.</p><p>It has been over 30 years since the first edition of the seismotectonic map was published by Greece's Geological Institute in 1989, which emerges the need for an update, as soon as dozens of strong earthquakes have occurred both on mainland and offshore, whose locations and fault kinematics have been studied and this information has to be taken into account in city and infrastructure planning. Moreover, the patterns of active tectonics and stress, the tectonic strain distribution, the annual ratio between seismic and geodetic moment release, the precise location of onshore active faults and the slip-rates of major faults are much better known today than they were 30 years ago.</p><p>Open-source mapping software and GIS tools are being used to showcase important up-to-date seismotectonic features together with critical geospatial information (motorways, railways, gas pipelines, electricity plants, etc) at a nationwide scale of 1:500,000. This updated product aims to reveal a comprehensive image of the regional crustal deformation in a useful manner for scientists, students, and stakeholders to obtain a first-order perception of seismic risk in the Greek territory, but, also, to be used as a basis for other applications in Geosciences.</p>

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