The sequence of moderate-size earthquakes at the junction of the Ligurian basin and the Corsica margin (western Mediterranean): The initiation of an active deformation zone revealed?

2016 ◽  
Vol 676 ◽  
pp. 135-147 ◽  
Author(s):  
Christophe Larroque ◽  
Bertrand Delouis ◽  
Françoise Sage ◽  
Marc Régnier ◽  
Nicole Béthoux ◽  
...  
Keyword(s):  
Deformation Zone ◽  
Western Mediterranean ◽  
Active Deformation ◽  
Moderate Size ◽  
Ligurian Basin

GPS Constraints on the Active Deformation in Tunisia: Implications on the Geodynamics of the Western Mediterranean

2020 ◽  
Author(s):  
Frédéric Masson ◽  
Mustapha Meghraoui ◽  
Najib Bahrouni ◽  
Mohammed Saleh ◽  
Maamri Ridha ◽  
...  
Keyword(s):  
Velocity Field ◽  
Plate Boundary ◽  
Western Mediterranean ◽  
African Plate ◽  
Active Deformation ◽  
Crustal Motion ◽  
Plate Convergence ◽  
Atlas Mountains ◽  
Tunisian Atlas ◽  
Geodetic Strain

<p>The plate boundary in the western Mediterranean includes the Tunisian Atlas Mountains. We study the active deformation of this area using GPS data collected from 2014 to 2018. WNW to NNW trending velocities express the crustal motion and geodetic strain field from the Sahara platform to the Tell Atlas, consistent with the African plate convergence. To the south, the velocities indicate a nearly WNW-ESE trending right-lateral motion of the Sahara fault-related fold belt with respect to the Sahara Platform. Further north and northeast, the significant decrease in velocities between the Eastern Platform and Central – Tell Atlas marks the NNW trending shortening deformation associated with local ENE – WSW extension visible in the Quaternary grabens. The velocity field and strain distribution associated with the active E-W trending right-lateral faulting and NE-SW fault-related folds sustain the existence of three main tectonic blocks and related transpression tectonics. The velocity field and pattern of active deformation in Tunisia document the oblique plate convergence of Africa towards Eurasia. </p>

Chronostratigraphy and paleomagnetism of Oligo-Miocene deposits of Corsica (France) : geodynamic implications for the liguro-provençal basin spreading

2003 ◽  
Vol 174 (4) ◽  
pp. 357-371 ◽  
Author(s):  
Jean Ferrandini ◽  
Jérôme Gattacceca ◽  
Michelle Ferrandini ◽  
Alan Deino ◽  
Marie-Christine Janin
Keyword(s):  
Short Interval ◽  
Western Mediterranean ◽  
Early Miocene ◽  
Paleomagnetic Data ◽  
Tyrrhenian Sea ◽  
Anticlockwise Rotation ◽  
Paleomagnetic Study ◽  
Sedimentary Succession ◽  
Two Stages ◽  
Ligurian Basin

Abstract In a context of convergence between Africa and Europe, the western Mediterranean domain is characterized by the opening of the Liguro-Provençal ocean in the early Miocene and of the Tyrrhenian Sea since the middle Miocene. These openings are preceded by an Oligocene rifting episod. New biostratigraphic, geochronologic and paleomagnetic data allow to propose an integrated stratigraphy sketch for the Oligo-Miocene period in Corsica. The continental syn-rift deposits, in the region of Ajaccio, have been dated as late Chattian from the presence of a mammal, Pomelomeryx boulangeri. Their paleomagnetic study indicates an anticlockwise rotation of 44 ±4° with regard to the stable Europe. The early Miocene succession was deposited on a contrasted topography inherited from the Oligocene glyptogenesis period. The lowermost Miocene deposits are represented by 4 pyroclastic flow deposits in southern Corsica. New 40Ar-39Ar datings on plagioclase concentrates give ages between 21.3 and 20.6 Ma (late Aquitanian). Paleomagnetic directions indicates that the rotation of Corsica had probably begun at this time. The Miocene marine sediments of the Bonifacio basin are divided in two formations. At the base, the Cala di Labra formation, that comprises 3 reef formations in coastal onlap (R1, R2, R3), is attributable to the Globigerinoides trilobus zone. In the environment of R1, miogypsin population includes mainly Miogypsina intermedia with a few M. globulina and M. cushmani. The absence of the less evolved forms (10 < V < 35) let us suppose that at least the lower Burdigalian is absent at Bonifacio because the region was emerged. R2 reef has a similar population (42 < V < 70), which suggests a rather short interval of time between the two stages of reef construction. On the other hand the R3 population contains only evolved forms (M. mediterranea) suggesting a late Burdigalian age. The end of the sedimentary succession (Bonifacio formation) is essentially represented by a pile of hydraulic dunes. The absence of Orbulina shows that this upper unit is older than late Langhian (biozone N9). Miocene sediments from Saint-Florent are divided into 3 marine formations bracketed by two continental ones. At the base, the continental formation of Fium’Albinu (equivalent to the Cala di Labra formation) is surmounted by the Torra formation attributed to Late Burdigalian based on the presence of G. trilobus and G. bisphericus. The Sant’Angelo formation (equivalent to the Bonifacio formation) developed from latest Burdigalian to late Langhian. The Farinole formation represents early Serravallian (base of the Globoquadrina altispira altispira zone). Despite the large number of studied sites in this study and others, the only reliable Oligo-Miocene paleomagnetic results in Corsica are the following ones : – the Vazzio formation indicates a rotation of 44 ± 4° after the late Oligocene, – the southern volcanic flows show that the rotation was in progress around 20.7 Ma (late Aquitanian), – the Fium’Albinu formation indicates a rotation of 30 ± 12° after early Burdigalian, – site B from Vigliotti and Kent [1990] gives a rotation of about 11 ± 5° after early Langhian. Our paleomagnetic data, together with the existing ones, associated to the biostratigraphic and geochronologic ages show that the opening of the Ligurian basin coincides with an anticlockwise rotation of 45° of Corsica, which begins between 23 and 21 Ma and ends around 15 Ma. This is in agreement with the idea of Sardinia and Corsica rotating as a single almost rigid block during Miocene times.

scholarly journals STUDI AWAL POLA STRUKTUR BUSUR MUKA ACEH, SUMATRA BAGIAN UTARA (INDONESIA): Penafsiran dan Analisis Peta Batimetri

2016 ◽  
Vol 8 (3) ◽  
pp. 105
Author(s):  
Haryadi Permana ◽  
L. Handayani
Keyword(s):  
Subduction Zone ◽  
Deformation Zone ◽  
Thrust Fault ◽  
Middle Part ◽  
Strike Slip ◽  
Strike Slip Fault ◽  
Zone Structure ◽  
Structural Pattern ◽  
Active Deformation ◽  
Plate Subduction

Analisis morfostruktur daerah penelitian menunjukan tiga unit struktur geologi yang berbeda, antara lain zona penunjaman, zona deformasi aktif dan busur muka termasuk didalamnya tinggian busur muka dan cekungan busur muka. Struktur geologi zona penunjaman lempeng teramati sepanjang Palung Sunda paralel dengan zona deformasi aktif. Struktur geologi pada Tinggian Busur Muka membentuk sistim prisma akresi yang disusun oleh sesar anjak, sesar geser, perlipatan dan perlipatan naik. Pola kelurusan struktur umumnya berarah berarah utara baratlaut-selatan tenggara di sebelah utara lintang 5°U, arah baratlaut-tenggara pada posisi 3°-5°U, kelurusan kemudian berbelok hampir barat-timur di sekitar 2°-3°U. Perubahan arah pola kelurusan struktur tersebut ditafsirkan sebagai jawaban terhadap naiknya tingkat kemiringan penunjaman lempeng dari daerah Simeulue ke arah Lintang 5°U -7°U atau secara umum dari selatan Sumatra ke arah utara Sumatra. Di bagian tengah daerah telitian berkembang kelurusan patahan berarah utara-selatan yang memotong kelurusan berarah baratlaut-tenggara. Kelurusan tersebut ditafsirkan sebagai patahan geser dekstral dan kemungkinan masih aktif. Kata Kunci: Analisis morfostruktur, zona penunjaman, zona deformasi aktif, busur muka, kelurusan, sesar anjak, sesar geser, perlipatan, perlipatan naik, kemiringan penunjaman lempeng Morphostructure analyses of study area demonstrate three different units of geological structures: subduction zone, active deformation zone and fore-arc region, which include Fore Arc High and Fore Arc Basin. The plate subduction zone observes along Sunda Trench parallel with active deformation zone. Structure geology in Fore Arc High builds an accretionary prism system. It was composed by thrust fault, strike slip fault, folding and thrust fold. General trend of structural pattern is NNE-SSE at the north of 5°N, NW-SE direction at around 3°-5°N and changed in direction relative to E-W at about 2°-3°N. This direction variation of structural pattern trend was interpreted as a response to increase of obliquity degree of subducted plate from Simeulue area to 5° -7°N, or in general, from southern of Sumatra to north of Sumatra. NS trend lineament has developed in the middle part of study area that also sliced the NW-SE main structural direction. These structural lineaments interpreted as dextral strike slip fault and it is possibly still active. Keywords: morphostructure analyses, subduction zone, active deformation zone, fore-arc lineament, thrust fault, strike slip, folding, thrust fold, plat, plate subduction obliquity

scholarly journals Recent and active deformation pattern off the easternmost Algerian margin, Western Mediterranean Sea: New evidence for contractional tectonic reactivation

2009 ◽  
Vol 261 (1-4) ◽  
pp. 17-32 ◽  
Author(s):  
Abdelaziz Kherroubi ◽  
Jacques Déverchère ◽  
Abdelkarim Yelles ◽  
Bernard Mercier de Lépinay ◽  
Anne Domzig ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Deformation Pattern ◽  
Active Deformation ◽  
Western Mediterranean Sea ◽  
New Evidence

Constraint of active deformation and transpression tectonics along the plate boundary in North Africa

2020 ◽  
Author(s):  
Mustapha Meghraoui ◽  
Frederic Masson ◽  
Nejib Bahrouni ◽  
Abdelilah Tahayt ◽  
Mohamed Saleh ◽  
...  
Keyword(s):  
North Africa ◽  
Plate Boundary ◽  
Western Mediterranean ◽  
Published Data ◽  
Strain Partitioning ◽  
Block Rotation ◽  
Tectonic Structures ◽  
Active Deformation ◽  
Moment Tensors ◽  
Plate Convergence

<p>The Maghrebian tectonic domain in North Africa is here examined in the light of the recent GPS and seismotectonic results. The region includes the plate boundary in the western Mediterranean previously characterized by transpression and block rotation. The crustal deformation is documented along the Atlas Mountains in terms of the displacement field, with strain partitioning largely controlled by plate motions. The tectonic and seismotectonic analysis is based on our published data on shortening directions of Quaternary faulting and folding compared with present-day seismotectonic characteristics (earthquake moment tensors) of significant seismic events that allow an estimate of local and regional deformation rates in North Africa. Shortening directions oriented NE-SW to NW-SE for the Pliocene and Quaternary, respectively, and the S shape of the Quaternary anticline axes are in agreement with the 2°/Myr to 4°/Myr clockwise rotation obtained from paleomagnetic results on small tectonic blocks in the Tell Atlas. The continuous GPS data and results are obtained from the network in Morocco operative 1999 to 2006, the REGAT network in Algeria since 2007, and the network in Tunisia with data collected from 2014 to 2018. In addition, we add the most recent GPS results in southern Spain and southern Italy. The NW-SE to NNW-SSE 5 ±1.5 mm/yr convergence velocity and strain distribution of the Maghrebian tectonic domain is controlled by crustal block tectonics driven by E-W trending right-lateral faulting and NE-SW thrust-related folding. The correlation between the active transpression tectonic structures and velocity field shows a geodynamic framework consistent with the oblique plate convergence of Africa towards Eurasia. </p>

Pollutant lad sources and deposition in the Western Mediterranean

2003 ◽  
Vol 107 ◽  
pp. 875-878 ◽  
Author(s):  
J. Miralles ◽  
O. Radakovitch ◽  
A. Véron ◽  
J. K. Cochran ◽  
P. Masqué ◽  
...  
Keyword(s):  
Western Mediterranean

Simulation of vibration piercing of pipe blank at press

2020 ◽  
Vol 76 (11) ◽  
pp. 1128-1138
Author(s):  
S. R. Rakhmanov
Keyword(s):  
High Frequency ◽  
Deformation Zone ◽  
Pipe Blank ◽  
Equipment Operation ◽  
Metal Deformation ◽  
Technological Tool ◽  
High Frequency Vibrations ◽  
Pipe Blanks ◽  
Wave Phenomena

In some cases, the processes of piercing or expanding pipe blanks involve the use of high-frequency active vibrations. However, due to insufficient knowledge, these processes are not widely used in the practice of seamless pipes production. In particular, the problems of increasing the efficiency of the processes of piercing or expanding a pipe blank at a piercing press using high-frequency vibrations are being solved without proper research and, as a rule, by experiments. The elaboration of modern technological processes for the production of seamless pipes using high-frequency vibrations is directly related to the choice of rational modes of metal deformation and the prediction resistance indicators of technological tools and the reliability of equipment operation. The creation of a mathematical model of the process of vibrating piercing (expansion) of an axisymmetric pipe blank at a piercing press of a pipe press facility is an actual task. A calculation scheme for the process of piercing a pipe plank has been elaborated. A dependence was obtained characterizing the speed of front of plastic deformation propagation on the speed of penetration of a vibrated axisymmetric mandrel into the pipe workpiece being pierced. The dynamic characteristics of the occurrence of wave phenomena in the metal being pierced under the influence of a vibrated tool have been determined, which significantly complements the previously known ideas about the stress-strain state of the metal in the deformation zone. The deformation fields in the zones of the disturbed region of the deformation zone were established, taking into account the high-frequency vibrations of the technological tool. It has been established that the choice of rational parameters (amplitude-frequency characteristics) of the vibration piercing process of a pipe blank results in significant increase in the efficiency of the process, the durability of the technological tool and the quality of the pierced blanks.

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