scholarly journals GEOLOGICAL, GEOMORPHOLOGICAL AND TECTONIC STRUCTURE OF NE ATTICA AND SEISMIC HAZARD IMPLICATIONS FOR THE NORTHERN EDGE OF THE ATHENS PLAIN

2018 ◽  
Vol 40 (1) ◽  
pp. 425 ◽  
Author(s):  
D. Papanikolaou ◽  
I. Papanikolaou
Keyword(s):  
Cross Sections ◽  
Slip Rate ◽  
Normal Faults ◽  
Tectonic Block ◽  
Drainage Basins ◽  
Seismicity Pattern ◽  
The North ◽  
Northern Edge ◽  
Zone Ii ◽  
Flow Directions

A synthesis of geology, geomorphology and tectonics has been compiled regarding the NE part of Attica. This synthesis helps us clarify how old and new structures interrelate and interact to provide the present day setting. Geological, geomorphological maps, and cross-sections are provided to help us depict and extract data. The region of NE Attica forms a tilted tectonic block bounded by the Afidnai fault to the south and the Oropos fault to the north that rotates to the S-SW. This tilt produces southern trending flow directions draining the footwall within the block. Drainage basins are highly asymmetric due to the presence of active normal faults producing a combination of fault parallel and fault perpendicular flow directions. This block is also divided by a NNE-SSW detachment fault that separates the metamorphic units to the east from the unmetamorphic units to the west. It was active in Late Miocene-Early Pliocene and produced several hundred meters of debris-flow deposits. This detachment influences the geometry, style and intensity of deformation, but also the seismicity pattern. In particular, this detachment coincides with the line separating zone I (lowest category of seismic risk) from zone II of the national seismic building code. Finally, the Athens plain is bounded northwards by the active, but low slip-rate E-W trending, 14 km long, Afidnai fault.

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 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.

Neogene kinematics and structural evolution of the Giudicarie Belt and eastern Southern Alpine orogenic front (Northern Italy)

2020 ◽  
Author(s):  
Vincent Verwater ◽  
Mark R. Handy ◽  
Eline Le Breton ◽  
Vincenzo Picotti ◽  
Azam Jozi Najafabadi ◽  
...  
Keyword(s):  
Cross Sections ◽  
Hanging Wall ◽  
Structural Evolution ◽  
Leading Edge ◽  
Strike Slip ◽  
Southern Alps ◽  
Normal Faults ◽  
Strain Partitioning ◽  
The North ◽  
Thickness Variations

<p>The eastern Southern Alps are part of the deformed leading edge of the Adriatic plate indenting the European plate to the north. Neogene deformation in the eastern Southern Alps is partitioned into three, kinematically linked fold-and-fault systems: (1) The Giudicarie Belt, (2) the Valsugana Thrust System and (3) the external fold-and-thrust systems of the orogenic front, including the strike-slip Schio-Vicenza Fault. We aim to constrain fault kinematics from the Southern Alpine orogenic front to the Northern Giudicarie Fault to better understand deformation of the Adriatic indenter since Miocene time.</p><p>The Giudicarie Belt is a sinistral transverse zone characterized by NNE-oriented faults. Some of these faults originated in the Mesozoic as NNE-SSW trending normal faults, which were inverted during Alpine orogeny. Most of the Mesozoic normal faults are oriented oblique to sub-parallel to the main Neogene shortening direction, which led to strain partitioning between thrust and strike-slip faults. This significant strike-slip component complicates kinematic and structural restoration of geological cross-sections in 2-D because rock units moved into and out of the section trace, distorting in-section shortening estimates.</p><p>To assess lateral variations in shortening and quantify strain partitioning along and across the strike of the Giudicarie Belt, we constructed and balanced a network of closely spaced cross-sections perpendicular to the main structural trend. Seven 2-D NNW-SSE cross-sections from the Northern Giudicarie Fault to the Southern Alpine orogenic front reveal that the amount of Neogene NNW-SSE shortening varies from 11 km in the vicinity of the Adige embayment to 27 km further NE, with most shortening (20 to 26 km) accommodated within the Valsugana and Giudicarie systems. Shortening differs on either side of the Trento-Cles, Schio-Vicenza (4 km difference) and Ballino-Garda (7 km difference) strike-slip faults. These faults are inherited Mesozoic faults that coincide with significant stratigraphic thickness variations, which we constrained along orogen-parallel cross-sections. The SW-NE variation in shortening is inferred to have been taken up by these sinistral strike-slip faults, but also including the Northern Giudicarie Fault, for which we estimate the minimum amount of slip to be 19 km.</p><p>Exposure of Pre-Permian basement in the hanging wall of thrusts indicates a thick-skinned style of deformation. Forward modelling using the MOVE Suite Software indicates that the depth of the detachments within the Pre-Permian basement is no greater than 20 km. A recently located cluster of minor seismic events (2017-2018) within the study area is aligned between 5 and 15 km along the modelled detachments. These earthquake clusters occur within the external fold-and-thrust systems of the orogenic front, suggesting that ongoing shortening is taken up within this system and that the Valsugana and Giudicarie systems are inactive today.</p>

Depositional environments and paleogeography in the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines formations, Alberta

1984 ◽  
Vol 21 (6) ◽  
pp. 698-714 ◽  
Author(s):  
David R. Taylor ◽  
Roger G. Walker
Keyword(s):  
Brackish Water ◽  
Late Jurassic ◽  
Major Change ◽  
Depositional Environments ◽  
Fluvial Deposits ◽  
Maximum Thickness ◽  
The North ◽  
Major Exception ◽  
Flow Directions ◽  
Sand Bodies

The marine Moosebar Formation (Albian) has a currently accepted southerly limit at Fall Creek (Ram River area). It consists of marine mudstones with some hummocky and swaley cross-stratified sandstones indicating a storm-dominated Moosebar (Clearwater) sea. We have traced a tongue of the Moosebar southward to the Elbow River area (150 km southeast of Fall Creek), where there is a brackish-water ostracod fauna. Paleoflow directions are essentially northwestward (vector mean 318°), roughly agreeing with turbidite sole marks (329°) in the Moosebar of northeastern British Columbia.The Moosebar sea transgressed southward over fluvial deposits of the Gladstone Formation. In the Gladstone, thick channel sands (4–8 m) are commonly multistorey (up to about 15 m), with well developed lateral accretion surfaces. The strike of the lateral accretion surfaces and the orientation of the walls of channels and scours indicate northwestward flow (various vector means in the range 307–339°). The Moosebar transgression was terminated by construction of the Beaver Mines floodplain, with thick, multistorey sand bodies up to about 35 m thick. Flow directions are variable, but various vector means roughly cluster in the north to northeast segment. This indicates a major change in dispersal direction from the Gladstone and Moosebar formations.A review of many Late Jurassic and Cretaceous units shows a dominant dispersal of sand parallel to regional strike. This flow is mostly north-northwestward (Passage beds, Cadomin, Gladstone, Moosebar, Gates, Chungo), with the southeasterly dispersal of the Cardium being the major exception. Only at times of maximum thickness of clastic input (Belly River and higher units, and possibly Kootenay but there are no published paleocurrent data) does the sediment disperse directly eastward or northeastward from the Cordillera toward the Plains.

scholarly journals Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum

2016 ◽  
Vol 4 (4) ◽  
pp. 831-869 ◽  
Author(s):  
Andrew D. Wickert
Keyword(s):  
North American ◽  
Drainage Basin ◽  
Ice Sheets ◽  
Glacial Isostatic Adjustment ◽  
Drainage Basins ◽  
Last Glacial ◽  
Isostatic Adjustment ◽  
The North ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract. Over the last glacial cycle, ice sheets and the resultant glacial isostatic adjustment (GIA) rearranged river systems. As these riverine threads that tied the ice sheets to the sea were stretched, severed, and restructured, they also shrank and swelled with the pulse of meltwater inputs and time-varying drainage basin areas, and sometimes delivered enough meltwater to the oceans in the right places to influence global climate. Here I present a general method to compute past river flow paths, drainage basin geometries, and river discharges, by combining models of past ice sheets, glacial isostatic adjustment, and climate. The result is a time series of synthetic paleohydrographs and drainage basin maps from the Last Glacial Maximum to present for nine major drainage basins – the Mississippi, Rio Grande, Colorado, Columbia, Mackenzie, Hudson Bay, Saint Lawrence, Hudson, and Susquehanna/Chesapeake Bay. These are based on five published reconstructions of the North American ice sheets. I compare these maps with drainage reconstructions and discharge histories based on a review of observational evidence, including river deposits and terraces, isotopic records, mineral provenance markers, glacial moraine histories, and evidence of ice stream and tunnel valley flow directions. The sharp boundaries of the reconstructed past drainage basins complement the flexurally smoothed GIA signal that is more often used to validate ice-sheet reconstructions, and provide a complementary framework to reduce nonuniqueness in model reconstructions of the North American ice-sheet complex.

scholarly journals Evaluation of the Moisture Sources in two Extreme Landfalling Atmospheric River Events using an Eulerian WRF-Tracers tool

2017 ◽  
Author(s):  
Jorge Eiras-Barca ◽  
Francina Dominguez ◽  
Huancui Hu ◽  
A. Daniel Garaboa-Paz ◽  
Gonzalo Miguez-Macho
Keyword(s):  
Cross Sections ◽  
North Atlantic ◽  
Cold Front ◽  
Wrf Model ◽  
Atmospheric River ◽  
The North ◽  
Northern Latitudes ◽  
The Pacific ◽  
Low Level Jet ◽  
Tropical Moisture

Abstract. A new 3D Tracer tool is coupled to the WRF model to analyze the origin of the moisture in two extreme Atmospheric River (AR) events: the so-called Great Coast Gale of 2007 in the Pacific Basin, and the Great Storm of 1987 in the North Atlantic. Results show that between 80 % and 90 % of the moisture advected by the ARs, as well as between 70 % and 80 % of the associated precipitation have a tropical or subtropical origin. Local convergence transport is responsible for the remaining moisture and precipitation. The ratio of tropical moisture to total moisture is maximized as the cold front arrives to land. Vertical cross sections of the moisture suggest that the maximum in humidity does not necessarily coincide with the Low-Level Jet (LLJ) of the extratropical cyclone. Instead, the amount of tropical humidity is maximized in the lowest atmospheric level in southern latitudes, and can be located above, below or ahead the LLJ in northern latitudes in both analyzed cases.

scholarly journals A 60 000 year Greenland stratigraphic ice core chronology

2008 ◽  
Vol 4 (1) ◽  
pp. 47-57 ◽  
Author(s):  
A. Svensson ◽  
K. K. Andersen ◽  
M. Bigler ◽  
H. B. Clausen ◽  
D. Dahl-Jensen ◽  
...  
Keyword(s):  
North Atlantic ◽  
Time Scale ◽  
Ice Core ◽  
Ice Cores ◽  
The North ◽  
Annual Layer ◽  
Zone Ii ◽  
Absolute Age ◽  
Age Estimates ◽  
New Time

Abstract. The Greenland Ice Core Chronology 2005 (GICC05) is a time scale based on annual layer counting of high-resolution records from Greenland ice cores. Whereas the Holocene part of the time scale is based on various records from the DYE-3, the GRIP, and the NorthGRIP ice cores, the glacial part is solely based on NorthGRIP records. Here we present an 18 ka extension of the time scale such that GICC05 continuously covers the past 60 ka. The new section of the time scale places the onset of Greenland Interstadial 12 (GI-12) at 46.9±1.0 ka b2k (before year AD 2000), the North Atlantic Ash Zone II layer in GI-15 at 55.4±1.2 ka b2k, and the onset of GI-17 at 59.4±1.3 ka b2k. The error estimates are derived from the accumulated number of uncertain annual layers. In the 40–60 ka interval, the new time scale has a discrepancy with the Meese-Sowers GISP2 time scale of up to 2.4 ka. Assuming that the Greenland climatic events are synchronous with those seen in the Chinese Hulu Cave speleothem record, GICC05 compares well to the time scale of that record with absolute age differences of less than 800 years throughout the 60 ka period. The new time scale is generally in close agreement with other independently dated records and reference horizons, such as the Laschamp geomagnetic excursion, the French Villars Cave and the Austrian Kleegruben Cave speleothem records, suggesting high accuracy of both event durations and absolute age estimates.

Age and growth of the Patagonian lizard Phymaturus patagonicus

2006 ◽  
Vol 27 (3) ◽  
pp. 385-392 ◽  
Author(s):  
Carla Piantoni ◽  
Victor Cussac ◽  
Nora Ibargüengoytía
Keyword(s):  
Body Length ◽  
Cross Sections ◽  
Growth Dynamics ◽  
Strong Relationship ◽  
Age And Growth ◽  
Adult Males ◽  
Patagonian Steppe ◽  
The North ◽  
Sigmoidal Curve ◽  
Reproductive Cycles

AbstractThe growth dynamics of Phymaturus patagonicus, a diurnal, herbivorous and viviparous lizard from the Argentinean Patagonian steppe, was studied using eight juveniles (two born in the laboratory), 11 adult females and eight adult males. Histological cross sections of femoral bones were analysed to determine if individuals show osseous growth marks and if these marks provide useful age estimates. Individual ages were assessed after estimating the reabsorbed rings in relation to snout-vent length. There was a strong relationship between body length and estimated age, modelled by a sigmoidal curve. Sexual maturity was found to be reached at seven years in females and nine in males and the maximum life span was estimated to be 16 years. No difference in body length was observed between the same-age females and males. We postulate that severe environments such as the north Patagonian steppe play a significant role in the selection of not only modes of reproduction but also delayed maturity and prolonged reproductive cycles, a combination that results in low fecundity.

scholarly journals Morphological analysis of hummocks in debris avalanche deposits around Mt Erciyes, central Turkey

2017 ◽  
Author(s):  
Yuichi S. Hayakawa ◽  
Hidetsugu Yoshida ◽  
Hiroyuki Obanawa ◽  
Ryutaro Naruhashi ◽  
Koji Okumura ◽  
...  
Keyword(s):  
Cross Sections ◽  
Flow Direction ◽  
Debris Avalanche ◽  
Caldera Wall ◽  
High Definition ◽  
Sector Collapse ◽  
Initial Flow ◽  
The North ◽  
Aircraft System ◽  
Central Turkey

Abstract. Debris avalanche caused by the sector collapse of a volcanic mountain often forms characteristic depositional landforms including hummocks. Not only sedimentological but also geomorphological analyses of debris avalanche deposits (DAD) are crucial to clarify the size, mechanisms, and processes of the debris avalanche. We investigate the morphology of hummocks newly identified in the DAD at the north-eastern flank of Mt. Erciyes in Kayseri, central Turkey, likely formed in the late Pleistocene. Using a remotely piloted aircraft system (RPAS) and the structure-from-motion multi-view stereo photogrammetry (SfM), we obtained high-definition digital elevation model (DEM) and orthorectified image of the DAD surface with hummocks. Detailed geometric features of the hummocks are investigated using the RPAS-derived high-definition DEM. The source volume of the DAD was also estimated by reconstructing the original shape of the mountain body using a lower-resolution satellite-based DEM. For this, topographic cross sections are examined based on the slopes around the scar that are regarded as the remnant topography preserved since the sector collapse. The spatial distribution of hummocks shows an unusual pattern regarding the distance-size relationships, i.e., anomalously concentrated in a certain distance from the source. The hummocks are found to be aligned toward the flow direction of the debris avalanche, suggesting the extensional regime of the debris avalanche. These facts indicate that this debris avalanche did not follow the typical flow type of debris avalanches observed in the other cases. Instead, the topographic constraints by former caldera wall and fault-induced lineaments could have strongly affected the flow course and pattern in this particular case: The pre-existing caldera wall topography could have acted as the topographic barriers for the debris avalanche to force the initial flow to turn northward, and the flow regime to be once compressional followed by extensional at the narrow and steepened outlet valley. Also, the estimated volume of the DAD 12–15 × 108 m3 gives its mean thickness of 60–75 m, which is much deeper than the reported cases of other DADs. This suggests that the debris avalanche could have flown down to the far downstream areas from the presently-observed limit of the DAD extent. Assessments of the DAD including the results of this study can provide further insights into the risk and mitigation of potential disasters in the study area.

Late Pleistocene extension and strike-slip in the Dead Sea Basin

2004 ◽  
Vol 141 (5) ◽  
pp. 565-572 ◽  
Author(s):  
YUVAL BARTOV ◽  
AMIR SAGY
Keyword(s):  
Internal Structure ◽  
Slip Rate ◽  
Dead Sea ◽  
Strike Slip ◽  
Normal Faults ◽  
Small Scale ◽  
Dead Sea Basin ◽  
Pull Apart Basin ◽  
Western Border ◽  
The Dead

A newly discovered active small-scale pull-apart (Mor structure), located in the western part of the Dead Sea Basin, shows recent basin-parallel extension and strike-slip faulting, and offers a rare view of pull-apart internal structure. The Mor structure is bounded by N–S-trending strike-slip faults, and cross-cut by low-angle, E–W-trending normal faults. The geometry of this pull-apart suggests that displacement between the two stepped N–S strike-slip faults of the Mor structure is transferred by the extension associated with the normal faults. The continuing deformation in this structure is evident by the observation of at least three deformation episodes between 50 ka and present. The calculated sinistral slip-rate is 3.5 mm/yr over the last 30 000 years. This slip rate indicates that the Mor structure overlies the currently most active strike-slip fault within the western border of the Dead Sea pull-apart. The Mor structure is an example of a small pull-apart basin developed within a larger pull-apart. This type of hierarchy in pull-apart structures is an indication for their ongoing evolution.

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