scholarly journals 1881 and 1949 earthquakes at the Chios-Cesme Strait (Aegean Sea) and their relation to tsunamis

2005 ◽  
Vol 5 (5) ◽  
pp. 717-725 ◽  
Author(s):  
Y. Altinok ◽  
B. Alpar ◽  
N. Özer ◽  
C. Gazioglu

Abstract. The most earthquake-prone areas in the eastern central Aegean Sea are the Izmir Bay, the Karaburun peninsula and the island of Chios. The level of seismic activity and tsunami potential are influenced by the presence of normal faults around the region. There have been about 20 moderate-size earthquakes from 496 BC to 1949 AD. Among these earthquakes, the ones on the dates 20 March 1389, 13 November 1856, 19/22 January 1866, 3 April 1881 and 23 July 1949 produced tsunamis. The Chios-Cesme earthquake (1881, Mw 6.5) took place in the South of the Cesme strait while the Chios-Karaburun earthquake (1949, Mw 6.7) occurred in the North. The tsunamis caused by the earthquakes affected the coasts of Chios Island and Cesme. These waves are thought to be associated with the earthquakes and co-seismic underwater failures possibly occurred along the coasts of the Chios Island and Karaburun Peninsula or on the complex subaqueous morphology between these lands. Some sea waves or oscillations observed following the aftershocks are believed to be related to other natural phenomena; e.g. the seiches occurred mainly in open-narrow bays as triggered by the earthquakes.

2004 ◽  
Vol 36 (4) ◽  
pp. 1598 ◽  
Author(s):  
F. Alonso-Chaves ◽  
J. I. Soto ◽  
M. Orozco ◽  
A. A. Kilias ◽  
M. D. Tranos

The Betic (Southern Spain) and the Rif (Morocco) mountain chains, connected through the Gibraltar Strait, shapes a W-E elongated and arcuate Alpine orogenic belt. The Alborân Sea, in continuity to the east with the South Balearic Basin, is located in the inner part of this alpine belt. The Iberian and African continental forelands bound the region as a whole to the north and south, respectively, and to the east it is connected to the oceanic Sardine-Balearic Basin. The peculiarities of these westernmost Mediterranean chains result from: (1) its position between two large convergent plates -Africa and Europe- that have had variable directions of relative motion since the late Cretaceous; and (2) the Neogene westward migration of the orogenic hinterland and its simultaneous "back-arc"-like extension, generating the Alborén Sea basin. The complexes and large paleogeographic terrains traditionally recognized in the Betic and Rif chains belong to four pre-Neogene crustal domains: the South-Iberian and Maghrebian passive continental paleomargins (External Zones of the orogen), the Flysch Units, and the Alborân Crustal Domain composed mainly of a pre- Miocene metamorphosed thrust-stack (Nevado-Filabride, Alpujârride, and Malaguide complexes, from bottom to top). The boundaries between the main metamorphic complexes of the Alborân Domain are extensional detachments, which finally developed under brittle conditions and are commonly sealed by middle-to-late Miocene marine-to-continental sediments. They, nonetheless, are not the most recent structures in the Alborân Domain, because upright, E-W open folds warp the extensional detachments, and finally, high-angle normal faults and strike-slip faults, many of which are still active, offset folds and extensional detachments. The tectonic evolution of the Betic  Alborân orogenic system shows close similarities with the one depicted in other arcuate-shaped, Alpine mountain ranges in the Mediterranean, such as the Hellenic Arc and the Aegean Sea. Like in the westernmost Mediterranean, a thickened (pre Miocene) crust is bounding there a thinned, continental (?) basin. Extension is also formed here in a "back-arc" setting, being developed simultaneously with the N-S convergence between the African and European plates.


Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Paraskevi Nomikou ◽  
Dimitris Evangelidis ◽  
Dimitrios Papanikolaou ◽  
Danai Lampridou ◽  
Dimitris Litsas ◽  
...  

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.


2010 ◽  
Vol 181 (6) ◽  
pp. 477-501 ◽  
Author(s):  
Xavier Le Pichon ◽  
Claude Rangin ◽  
Youri Hamon ◽  
Nicolas Loget ◽  
Jin Ying Lin ◽  
...  

AbstractWe investigate the geodynamics of the Southeast Basin with the help of maps of the basement and of major sedimentary horizons based on available seismic reflection profiles and drill holes. We also present a study of the seismicity along the Middle Durance fault. The present seismic activity of the SE Basin cannot be attributed to the Africa/Eurasia shortening since spatial geodesy demonstrates that there is no significant motion of Corsica-Sardinia with respect to Eurasia and since gravitational collapse of the Alps has characterized the last few millions years. Our study demonstrates that the basement of this 140 by 200 km Triassic basin has been essentially undeformed since its formation, most probably because of the hardening of the cooling lithosphere after its 50% thinning during the Triassic distension. The regional geodynamics are thus dominated by the interaction of this rigid unit with the surrounding zones of active deformation. The 12 km thick Mesozoic sediment cover includes at its base an up to 4 km thick mostly evaporitic Triassic layer that is hot and consequently highly fluid. The sedimentary cover is thus decoupled from the basement. As a result, the sedimentary cover does not have enough strength to produce reliefs exceeding about 500 to 750 m. That the deformation and seismicity affecting the basin are the results of cover tectonics is confirmed by the fact that seismic activity in the basin only affects the sedimentary cover. Based on our mapping of the structure of the basin, we propose a simple mechanism accounting for the Neogene deformation of the sedimentary cover. The formation of the higher Alps has first resulted to the north in the shortening of the Diois-Baronnies sedimentary cover that elevated the top of Jurassic horizons by about 4 km with respect to surrounding areas to the south and west. There was thus passage from a brittle-ductile basement decollement within the higher Alps to an evaporitic decollement within the Diois-Baronnies. This shortening and consequent elevation finally induced the southward motion of the basin cover south of the Lure mountain during and after the Middle Miocene. This southward motion was absorbed by the formation of the Luberon and Trévaresse mountains to the south. To the east of the Durance fault, there is no large sediment cover. The seismicity there, is related to the absorption of the Alps collapse within the basement itself. To the west of the Salon-Cavaillon fault, on the other hand, gravity induces a NNE motion of the sedimentary cover with extension to the south and shortening to the north near Mont Ventoux. When considering the seismicity of this area, it is thus important to distinguish between the western Basin panel, west of the Salon-Cavaillon fault affected by very slow NNE gliding of the sedimentary cover, with extension to the south and shortening to the north; the central Basin panel west of the Durance fault with S gliding of the sedimentary cover and increasing shortening to the south; and finally the basement panel east of the Durance fault with intrabasement absorption of the Alps collapse through strike-slip and thrust faults.


2020 ◽  
Author(s):  
Berrocoso Manuel ◽  
Del Valle Arroyo Pablo Emilio ◽  
Colorado Jaramillo David Julián ◽  
Gárate Jorge ◽  
Fernández-Ros Alberto ◽  
...  

<p>The northwest of South America is conformed by the territories of Ecuador, Colombia and Venezuela. Great part of these territories make up the Northern Andes Block (BAN). The tectonic and volcanic activity in the northwest of South America is directly related to the interaction of the South American plate, and the Nazca and Caribbean plates, with the Maracaibo and Panama-Chocó micro plates. The high seismic activity and the high magnitude of the recorded earthquakes make any study necessary to define this complex geodynamic region more precisely. This work presents the velocity models obtained through GNSS-GPS observations obtained in public continuous monitoring stations in the region. The observations of the Magna-eco network (Agustín Codazzi Geographic Institute) are integrated with models already obtained by other authors from the observations of the GEORED network (Colombian Geological Service). The observations have been processed using Bernese software v.52 using the PPP technique; obtaining topocentric time series. To obtain the speeds, a process of filtering and adjustment of the topocentric series has been carried out. Based on this velocity model, regional structures have been defined within the Northern Andes Block through a differentiation process based on the corresponding speeds of the South American, Nazca and Caribbean tectonic plates. Local geodynamic structures within the BAN itself have been established through cluster analysis based on both the direction and the magnitude of each of the vectors obtained. Finally, these structures have been correlated with the most significant geodynamic elements (fractures, faults, subduction processes, etc.) and with the associated seismic activity.</p>


2003 ◽  
Vol 140 (1) ◽  
pp. 45-61 ◽  
Author(s):  
IOANNIS K. KOUKOUVELAS ◽  
SOTIRIOS KOKKALAS

Synmagmatic and solid-state structures within the Naxos pluton and its rim may provide insight into the interplay between plutonism and regional deformation at upper-crustal level. Within the hornblende–biotite granite of western Naxos, synmagmatic foliations display two distinct patterns, onion-skin in the north and tangential to the rim in the south. The two areas are separated by the NE-trending Glinadon fault. Deformed mafic enclaves in the pluton are prolate, with their long axes parallel to the synmagmatic lineation. In contrast, phenocryst distribution analysis, using the Fry method, defines an apparent oblate strain with a horizontal stretching lineation. Planar markers within the pluton progressively steepen through the vertical at the east pluton border. Several lines of evidence, such as dykes intruding axial areas of rim-parallel folds, foliated or folded aplite veins, folds and spaced cleavage in the mollase, and inverted stratigraphy, suggest pluton emplacement and deformation during transpressional deformation. A northward divergent flow regime with magma spreading out mainly from the Naxos fault, and the deflection of both the synmagmatic foliation pattern and the flow lines at the Glinadon fault, suggest that the NE–SW- and N–S-trending faults were active during pluton formation. In the south the pluton has grown by the expansion of dykes occupying P-shear positions with respect with the Naxos fault; in the north a piecemeal block down-drop complements this process and favours voluminous magma concentration. During the late evolutionary stages of pluton construction, the magma chamber was compartmentalized into NE-trending sectors affected by block rotation in an anticlockwise manner. Understanding the role of faults in the emplacement of the Naxos pluton is important for understanding emplacement of other plutons in the Aegean Sea region, since most of them are controlled by N–S- (Ikaria pluton) or NE- (Tinos, Serifos and Delos plutons) trending faults.


2017 ◽  
Vol 43 (1) ◽  
pp. 32 ◽  
Author(s):  
J. Makris

By constraining gravity modelling by Deep Seismic Soundings (DSS) and the Bouguer gravity field of Greece a 3-D density-velocity model of the crust and upper mantle was developed. It was shown that in the north Aegean Trough and the Thermaikos Basins the sediments exceed 7 km in thickness. The basins along the western Hellenides and the coastal regions of western Greece are filled with sediments of up to 10 km thickness, including the Prepulia and Alpine metamorphic limestones. The thickest sedimentary series however, were mapped offshore southwest and southeast of Crete and are of the order of 12 to 14 km. The crust along western Greece and the Peloponnese ranges between 42 and 32 km thickness while the Aegean region is floored by a stretched continental crust varying between 24 to 26 km in the north and eastern parts and thins to only 16 km at the central Cretan Sea. The upper mantle below the Aegean Sea is occupied by a lithothermal system of low density (3.25 gr/cm³) and Vp velocity (7.7 km/s), which is associated with the subducted Ionian lithosphere below the Aegean Sea. Isostasy is generally maintained at crustal and subcrustal levels except for the compressional domain of western Greece and the transition between the Mediterranean Ridge and the continental backstop. The isotherms computed from the Heat Flow density data and the density model showed a significant uplift of the temperature field below the Aegean domain. The 400°C isotherm is encountered at less than 10 Km depth. Tectonic deformation is controlled by dextral wrench faulting in the Aegean domain, while western Greece is dominated by compression and crustal shortening. Strike-slip and normal faults accommodate the western Hellenic thrusts and the westwards sliding of the Alpine napes, using the Triassic evaporates as lubricants.


2018 ◽  
Vol 5 ◽  
pp. 131-165 ◽  
Author(s):  
Valentin Zuchuat ◽  
Arve R.N. Sleveland ◽  
Douglas A. Sprinkel ◽  
Algirdas Rimkus ◽  
Alvar Braathen ◽  
...  

Based on a methodic sedimentological analysis, the Late Jurassic (Oxfordian) Curtis Formation unravels the intricate facies variability which occurs in a tide-dominated, fluvially starved, low-gradient, semi-enclosed epicontinental basin. This unit crops out in east-central Utah, between the eolian deposits of the underlying Middle Jurassic (Callovian) Entrada Sandstone, from which it is separated by the J-3 unconformity, and the conformable overlying supratidal Summerville Formation of Oxfordian age. A high-resolution sedimentary analysis of the succession led to the recognition of eight facies associations (FA) with six sub-facies associations. Based on the specific three-dimensional arrangement of these eight facies associations, it is proposed to separate the Curtis Formation into three sub-units: the lower, middle and upper Curtis. The J-3 unconformity defines the base of the lower Curtis, which consists of upper shoreface to beach deposits (FA 2), mud-domi­nated (FA 3a) and sand-dominated heterolithic subtidal flat (FA 3b), sand-rich sub- to supratidal flat (FA 4a) and correlative tidal channel infill (FA 4c). It is capped by the middle Curtis, which coincides with the sub- to intertidal channel-dune-flat complex of FA 5, and its lower boundary corresponds to a transgressive surface of regional extent, identified as the Major Transgressive Surface (MTS). This surface suggests a potential correlation between the middle and the upper Curtis and the neighboring Todilto Member of the Wanakah Forma­tion or Todilto Formation. The upper Curtis consists of the heterolithic upper sub- to intertidal flat (FA 6) and coastal dry eolian dunes belonging to the Moab Member of the Curtis Formation (FA 7), and it conformably overlies the middle Curtis. The spatial distribution of these sub-units supports the distinction of three different sectors across the study area: sector 1 in the north, sector 2 in the south-southwest, and sector 3 in the east. In sector 1, the Curtis Formation is represented by its three sub-units, whereas sector 2 is dominated by the middle and upper Curtis, and sector 3 encompasses the extent of the Moab Member of the Curtis Formation. This study also highlights the composite nature of the J-3 unconformity, which was impacted by various processes occurring before the Curtis Formation was deposited, as well as during the development of the lower and middle Curtis. Local collapse features within the lower and middle Curtis are linked to sand fluid over­pressure within a remobilized sandy substratum, potentially triggered by seismic activity. Furthermore, the occurrence of a sub-regional angular relationship between the middle Curtis and substratum implies that the area of study was impacted by a regional deformational event during the Late Jurassic, before the deposition of the middle Curtis. The spatial distribution of these sub-units supports the distinction of three different sectors across the study area: sector 1 in the north, sector 2 in the south-southwest, and sector 3 in the east. In sector 1, the Curtis For­mation is represented by its three sub-units, whereas sector 2 is dominated by the middle and upper Curtis, and sector 3 encompasses the extent of the Moab Member of the Curtis Formation. This study also highlights the composite nature of the J-3 unconformity, which was impacted by various processes occurring before the Curtis Formation was deposited, as well as during the development of the lower and middle Curtis. Local collapse features within the lower and middle Curtis are linked to sand fluid over­pressure within a remobilized sandy substratum, potentially triggered by seismic activity. Furthermore, the occurrence of a sub-regional angular relationship between the middle Curtis and substratum implies that the area of study was impacted by a regional deformational event during the Late Jurassic, before the deposition of the middle Curtis.


Author(s):  
Kristian Svennevig ◽  
Peter Alsen ◽  
Pierpaolo Guarnieri ◽  
Jussi Hovikoski ◽  
Bodil Wesenberg Lauridsen ◽  
...  

The geological map sheet of Kilen in 1:100 000 scale covers the south-eastern part of the Carboniferous– Palaeogene Wandel Sea Basin in eastern North Greenland. The map area is dominated by the Flade Isblink ice cap, which separates several minor isolated landmasses. On the semi-nunatak of Kilen, the map is mainly based on oblique photogrammetry and stratigraphical field work while in Erik S. Henius Land, Nordostrundingen and northern Amdrup Land the map is based on field data collected during previous, 1:500 000 scale regional mapping. Twenty-one Palaeozoic–Mesozoic mappable units were identified on Kilen, while the surrounding areas comprise the Late Cretaceous Nakkehoved Formation to the north-east and the Late Carboniferous Foldedal Formation to the south-west. On Kilen, the description of Jurassic–Cretaceous units follows a recently published lithostratigraphy. The Upper Palaeozoic–lowermost Cretaceous strata comprise seven formations and an informal mélange unit. The overlying Lower–Upper Cretaceous succession comprises the Galadriel Fjeld and Sølverbæk Formations, which are subdivided into six and five units, respectively. In addition, the Quaternary Ymer Formation was mapped on south-east Kilen. The Upper Palaeozoic to Mesozoic strata of Kilen are faulted and folded. Several post-Coniacian NNW–SSE-trending normal faults are identified and found to be passively folded by a later N–S compressional event. A prominent subhorizontal fault, the Central Detachment, separates two thrust sheets, the Kilen Thrust Sheet in the footwall and the Hondal Elv Thrust Sheet in the hanging wall. The style of deformation and the structures found on Kilen are caused by compressional tectonics resulting in post-extensional, presumably Early Eocene, folding and thrusting and basin inversion. The structural history of the surrounding areas and their relation to Kilen await further studies.


2017 ◽  
Vol 47 (2) ◽  
pp. 498
Author(s):  
K.E. Bradley ◽  
E. Vassilakis ◽  
B.P. Weiss ◽  
L.H. Royden

Consistently shallow paleomagnetic inclinations measured in Early to Middle Miocene lacustrine and dacitic volcanic rocks of the Kymi-Aliveri basin have been cited as evidence for an anomalous geomagnetic field geometry or northward drift of the Aegean Sea region. We present new paleomagnetic data from the lacustrine beds that are instead not anomalously shallow and consistent with deposition near their present-day latitude as predicted by global apparent polar wander paths. Anomalously shallow inclinations and easterly declinations reported from the Oxylithos volcanics are an artifact of an inappropriate tilt correction. The excessively shallow paleomagnetic inclinations reported from the deformed Middle Miocene plutons on Mykonos and Naxos are consistent with reorientation of an original thermoremanent magnetization acquired during cooling below 580°C by subsequent ductile strain at temperatures of 400-500°C. Magnetization overprints observed in these rocks may reflect the acquisition of a stable chemical remanent magnetization lying parallel to the transposed high-temperature magnetization as the result of low-temperature (<350°C) maghemitization. We therefore find no convincing evidence for an anomalous Middle Miocene field geometry, northward drift of the Aegean, or back-tilting of the low-angle normal faults that constitute the North Cycladic Detachment System.


Author(s):  
Kristian Svennevig ◽  
Peter Alsen ◽  
Pierpaolo Guarnieri ◽  
Jussi Hovikoski ◽  
Bodil Wesenberg Lauridsen ◽  
...  

NOTE: This Map Description was published in a former series of GEUS Bulletin. Please use the original series name when citing this series, for example: Svennevig, K., Alsen, P., Guarnieri, P., Hovikoski, J., Wesenberg Lauridsen, B., Krarup Pedersen, G., Nøhr-Hansen, H., & Sheldon, E. (2018). Descriptive text to the Geological map of Greenland, 1:100 000, Kilen 81 Ø.1 Syd. Geological Survey of Denmark and Greenland Map Series 8, 1-29. https://doi.org/10.34194/geusm.v8.4526 _______________ The geological map sheet of Kilen in 1:100 000 scale covers the south-eastern part of the Carboniferous–Palaeogene Wandel Sea Basin in eastern North Greenland. The map area is dominated by the Flade Isblink ice cap, which separates several minor isolated landmasses. On the semi-nunatak of Kilen, the map is mainly based on oblique photogrammetry and stratigraphical field work while in Erik S. Henius Land, Nordostrundingen and northern Amdrup Land the map is based on field data collected during previous, 1:500 000 scale regional mapping. Twenty-one Palaeozoic–Mesozoic mappable units were identified on Kilen, while the surrounding areas comprise the Late Cretaceous Nakkehoved Formation to the north-east and the Late Carboniferous Foldedal Formation to the south-west. On Kilen, the description of Jurassic–Cretaceous units follows a recently published lithostratigraphy. The Upper Palaeozoic–lowermost Cretaceous strata comprise seven formations and an informal mélange unit. The overlying Lower–Upper Cretaceous succession comprises the Galadriel Fjeld and Sølverbæk Formations, which are subdivided into six and five units, respectively. In addition, the Quaternary Ymer Formation was mapped on south-east Kilen. The Upper Palaeozoic to Mesozoic strata of Kilen are faulted and folded. Several post-Coniacian NNW–SSE-trending normal faults are identified and found to be passively folded by a later N–S compressional event. A prominent subhorizontal fault, the Central Detachment, separates two thrust sheets, the Kilen Thrust Sheet in the footwall and the Hondal Elv Thrust Sheet in the hanging wall. The style of deformation and the structures found on Kilen are caused by compressional tectonics resulting in post-extensional, presumably Early Eocene, folding and thrusting and basin inversion. The structural history of the surrounding areas and their relation to Kilen await further studies.


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