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2021 ◽  
Author(s):  
◽  
Ilma Del Carmen Juarez Garfias

<p><b>The Alpine Fault is a major active continental transform fault that is late in its typical cycle of large earthquakes. Extensive paleoseismic research has revealed that the central segment of the Alpine Fault ruptures in M7+ earthquakes every 291±23 years and last ruptured in 1717 AD. The paleoseismic results also reveal that some places along the fault, which coincide with pronounced along-strike changes in fault characteristics, act as conditional barriers to rupture. The geometry, seismicity rates and geology of the Alpine Fault change along three principal segments (North Westland, Central and South Westland segments) but it is unclear whether source properties (e.g. stress drop) of near-fault seismicity also vary between those fault segments, and whether these properties have some influence on conditional segmentation of the Alpine Faultduring large earthquake rupture.</b></p> <p>To examine whether source properties of earthquakes can influence or elucidate the conditional segmentation of Alpine Fault earthquakes, we have computed stress drops of moderate-magnitude earthquakes occurring on and close to the Alpine Fault. We use an empirical Green’s function (EGF) approach and require each EGF earthquake to be highly correlated (cross-correlation ≥0.8) with its respective mainshock. We use data from dense, temporary seismometer networks, including DWARFS (Dense WestlandArrays Researching Fault Segmentation), a new two-part network designed to constrain seismogenic behaviour near key transitional boundaries. Our results investigate the spatial variability of these source properties along the length of the Alpine Fault, focusing on whether earthquakes at the rupture segment boundaries behave differently to those in the middle of previously identified rupture segments.</p> <p>We analyse individual P- and S-wave measurements of corner frequency and stress drop for 95 earthquakes close to (within 5 km) and on the Alpine Fault. Overall, the calculated stress drops range between 1–352 MPa and show good agreement with other studies both within New Zealand and worldwide. The stress drop values obtained for the three Alpine segment are: 1–143 MPa (median values of 8 and 9 MPa for P- and S-waves, respectively) for the South Westland/Central segment boundary zone, 2–309 MPa (median values of 17 and 39 MPa for P- and S-waves, respectively) for the Central segment and 1–352 MPa (median values of 15 and 19 MPa for P- and S-waves, respectively) for the North Westland/Central segment boundary zone. There are no marked differences in stress drop values along the North Westland and Central segments, but those values are slightly higher than along the South Westland segment.</p> <p>This may indicate a bigger difference in fault geometry, slip and seismicity rate compare with other segments, or that the South Westland segment is weaker than the other segments. We see no clear dependence of stress drop values on depth, magnitude or focal mechanism.</p>


2021 ◽  
Author(s):  
Ilma Del Carmen Juarez Garfias

<p><b>The Alpine Fault is a major active continental transform fault that is late in its typical cycle of large earthquakes. Extensive paleoseismic research has revealed that the central segment of the Alpine Fault ruptures in M7+ earthquakes every 291±23 years and last ruptured in 1717 AD. The paleoseismic results also reveal that some places along the fault, which coincide with pronounced along-strike changes in fault characteristics, act as conditional barriers to rupture. The geometry, seismicity rates and geology of the Alpine Fault change along three principal segments (North Westland, Central and South Westland segments) but it is unclear whether source properties (e.g. stress drop) of near-fault seismicity also vary between those fault segments, and whether these properties have some influence on conditional segmentation of the Alpine Faultduring large earthquake rupture.</b></p> <p>To examine whether source properties of earthquakes can influence or elucidate the conditional segmentation of Alpine Fault earthquakes, we have computed stress drops of moderate-magnitude earthquakes occurring on and close to the Alpine Fault. We use an empirical Green’s function (EGF) approach and require each EGF earthquake to be highly correlated (cross-correlation ≥0.8) with its respective mainshock. We use data from dense, temporary seismometer networks, including DWARFS (Dense WestlandArrays Researching Fault Segmentation), a new two-part network designed to constrain seismogenic behaviour near key transitional boundaries. Our results investigate the spatial variability of these source properties along the length of the Alpine Fault, focusing on whether earthquakes at the rupture segment boundaries behave differently to those in the middle of previously identified rupture segments.</p> <p>We analyse individual P- and S-wave measurements of corner frequency and stress drop for 95 earthquakes close to (within 5 km) and on the Alpine Fault. Overall, the calculated stress drops range between 1–352 MPa and show good agreement with other studies both within New Zealand and worldwide. The stress drop values obtained for the three Alpine segment are: 1–143 MPa (median values of 8 and 9 MPa for P- and S-waves, respectively) for the South Westland/Central segment boundary zone, 2–309 MPa (median values of 17 and 39 MPa for P- and S-waves, respectively) for the Central segment and 1–352 MPa (median values of 15 and 19 MPa for P- and S-waves, respectively) for the North Westland/Central segment boundary zone. There are no marked differences in stress drop values along the North Westland and Central segments, but those values are slightly higher than along the South Westland segment.</p> <p>This may indicate a bigger difference in fault geometry, slip and seismicity rate compare with other segments, or that the South Westland segment is weaker than the other segments. We see no clear dependence of stress drop values on depth, magnitude or focal mechanism.</p>


Author(s):  
Dr. Jayant Sinha

The Lodhma area, in the Ranchi district, constitutes the central segment of Chotanagpur Granite Gneissic Complex ( CGGC) and falls in the northeastern segment of Survey of India toposheet number 73E/4. The CGGC is mainly composed of variants of granitic rocks, amphibolites and metasedimentaries. The granitic rocks find good exposure in the area. They comprise predominantly of granite gneisses, crystalline massive granites and migmatites showing noticeable variations in mineralogy, texture, structure and associations. The regional strike of the lithounits of the area show almost E-W trend. However ambient structural controls have brought about local changes in the strike direction. The area has witnessed at least three phases of deformations which is reflected by three generations of folds, which are generally isoclinals. Petrogenetic characterization of granitic rocks and its variants in the area has been attempted using various geochemical tools involving major/ trace element studies and Niggli values. S –type parentage of these Granites have been established on the basis of distribution behavior of various chemical components present in it, thereby indicating role of pelitic schists in the generation of anatectic melt, which ultimately crystallized into granites. S-type lineage of these granites has also been further cemented with the help of several well established binary and ternary variation diagrams


2021 ◽  
Vol 9 ◽  
Author(s):  
Lei Sun ◽  
Paul Mann

The area of southeastern Papua New Guinea includes three active microplates – the Trobriand, Woodlark, and Solomon Sea plates – that are being deformed by regional convergence between the much larger Pacific and Australian Plates. The landward extent of the plate boundary between the Trobriand and Australian Plates corresponds to the Owen-Stanley Fault Zone (OSFZ), an onland and continuous 510 km-long left-lateral strike-slip fault that forms a linear, intermontane valley within the elongate Owen-Stanley Range (OSR) and continues as a 250 km-long low-angle normal fault along the margins of Goodenough and Woodlark basins. GPS geodesy reveals that the Trobriand microplate has undergone rapid counter-clockwise rotation since the Late Miocene (8.4 Ma) and that this rotation about a nearby pole of rotation predicts transpressional deformation along the 250 km-long northwestern segment of the OSFZ, strike-slip motion along a 100 km-long central segment, and transtension along the 270 km-long ESE-trending southeastern segment of OSFZ. In order to illustrate the along-strike variations in neotectonic uplift resulting from the changing structure of the OSFZ, we delineated 3903 river segments in the northeastern side of the OSR drainage divide and derived river longitudinal profiles along each river segment. Normalized steepness indices (ksn) and knickpoint clusters are the highest and most concentrated, respectively, for the northwestern transpressional segment of the OSR, moderately high and concentrated along the southeastern segment of the OSR, and the lowest and least concentrated along the central strike-slip segment. These geomorphological indices indicate that most of the plate boundary uplift occurs along the transpressional and transtensional segments that are connected by the central strike-slip zone. Within this overall pattern of structural variation, abrupt changes in the azimuth of the OSFZ create more localized anomalies in the geomorphological indices.


Author(s):  
P. Z. Mammadov ◽  
R. Y. Ganiyevа

The paper considers sedimentation process and objects of lateral development in deep-water uncompensated and shallow-water – epicontinental paleobasins developed at various evolution stages of South- Caspian and Middle-Caspian basins. The South Caspian megabasin is a great tectonic crustal element and a highly prospective sedimentary basin in the central segment of the Alpine-Himalayan mobile belt. The role of boundary structures of Scythian-Turan platform in the Middle Caspian (such as South-Caspian land and Karaboghaz arc) and avalanche sedimentation on the continental shelf in development of sedimentation units and specific shape objects of lateral development in many kilometers long sedimentary cover of South-Caspian basin has been shown. According to interpretation of seismo-stratigraphic data the inflow of paleodeltaic, avandelatic and turbidite objects of lateral development for infill of the Early Pliocene basin has been proved. Seismo-stratigraphic analysis, using other analyses (e.g. study of morphostructure of palaeorelief and thicknesses of the units and formations) and GSW, enabled the genesis of deposits in the underlying PS formations to be clarified from a new perspective and the favou- rable zones of formation of large lithological and stratigraphic traps for oil and gas accumulations to be identified.


2021 ◽  
Vol 3 ◽  
pp. 100018
Author(s):  
Girish Ch Kothyari ◽  
Raj Sunil Kandregula ◽  
Gaurav Chauhan ◽  
Bhawanisingh G. Desai ◽  
Ajay Kumar Taloor ◽  
...  

Petrology ◽  
2021 ◽  
Vol 29 (2) ◽  
pp. 195-220
Author(s):  
I. K. Kozakov ◽  
V. P. Kovach ◽  
E. B. Salnikova ◽  
A. N. Didenko ◽  
Yu. V. Plotkina ◽  
...  

2020 ◽  
Vol 55 ◽  
Author(s):  
Włodzimierz Wysoczański

The Component “Seven” in Slavic Phraseology and Paremical Units Units with a numeral component are clearly noticeable in phraseo-paremical resources. This is particularly the case of richly represented multiword combinations with the lexeme “seven”. The comparative analysis presented in this article considers the phrases and paremias of Slavic languages with the component “seven”. They manifest a conceptualising numerical dimension in indications of quantity and intensity by reference to the value of seven units of something, and also by variance or opposition within numerical indices with the central segment “seven”. Komponent „siedem” w słowiańskiej frazeologii i paremice W zasobach frazeologiczno-paremicznych wyraźnie zauważalne są jednostki z komponentem liczebnikowym, w szczególności bogato reprezentowane są związki z leksemem „siedem”. W przeprowadzonym badaniu porównawczym analizie poddano frazeologizmy i paremie języków słowiańskich ze składnikiem „siedem”. Ukazują one konceptualizacyjny wymiar liczbowy przejawiający się we wskazaniach na miarę ilości oraz intensywność poprzez odniesienie do wartości siedmiu jednostek czegoś, a także poprzez oboczność bądź przeciwstawność w obrębie odniesień liczbowych z ośrodkowym segmentem „siedem”.


2020 ◽  
Vol 13 (5) ◽  
pp. 36-40
Author(s):  
A.V. Seregin ◽  
◽  
T.R. Indarokov ◽  
N.A. Shustitsky ◽  
A.A. Seregin ◽  
...  

Introduction. Despite the improvement of various methods of surgical and ablative methods of treating kidney cancer, the question remains about the functional state of the kidney after surgical treatment. Along with the achievement of oncological results, the preservation of renal function is the main task in the treatment of tumorous diseases of the kidneys. Aim. To evaluate the functional results of organ-preserving operations with a preventive suture with preserved blood flow, as well as in patients who underwent a resection of the kidney with compression of the renal pedicle, using nephroscintigraphy. Material and Methods. The study included 175 patients in stages pT1a-T2bN0M0, which are divided into 2 groups. Group 1 – 150 patients who underwent organ-preserving options with the use of preventive hemostatic sutures, allowing operations to be performed without clamping the kidney leg. 25 patients underwent a resection of the kidney with compression of the renal pedicle. To assess renal function, patients underwent dynamic nephroscintigraphy. In the first group, the tumor was located in the central segment in 64 patients, in the upper segment in 45 patients, in the lower segment in 41 patients. Stage T1a was established in 74 patients, stage T1b in 53 patients, stage T2a in 4 patients. In 19 patients diagnosed with cystic T1a cancers. In the second group in the central segment – in 10 patients, in the upper segment in 7 patients and in 8 patients in the lower. According to the stages, patients were divided as follows – T1a – 16, T1b – 8, T2a – 1. Results. Organ-preserving operations were performed for all patients. In the first group, in no case did the renal pedicle be pinched. The average time of thermal ischemia in the second group was 13 ± 2 min. The perfusion and renal index for the operated kidney in both groups was comparable, and amounted to 54.13 ± 2% and 53.24 ± 4%. However, after surgical treatment, the indicators were significantly different. In the first group, the perfusion index was 46.82 ± 2.39% against 35 ± 1.52% in the second, the renal index in the first group was 46.82 ± 2.39%, against 39 ± 0.88% in the second. Conclusion. Thus, even short-term thermal ischemia leads to significant impairment of renal function. Preventive suture allows you to remove a tumor from any part of the kidney, while maintaining blood flow, and allows you to protect the renal parenchyma from ischemic damage.


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