Showing papers in "Tectonophysics in 1983"

TL;DR: A review of recent work on microcracks in rock can be found in this paper, with a focus on the morphogenesis, kinematics, dynamics, population statistics and observational techniques.

TL;DR: In this paper, the authors reconstruct the motion of the continents over hotspots for the past 200 million years and find that the relative motions of the plates are determined from magnetic anomaly isochrons in the oceans.

TL;DR: In this paper, the authors show that the discontinuity in the river profiles and the other features are controlled by a major tectonic boundary between the rising High Himalayas and the Lesser Himalaysas.

TL;DR: In this paper, the authors discuss the partitioning of deformation in a flowing rock mass and discuss the factors that affect flow partitioning (e.g., spin versus non-coaxial deformation).

TL;DR: In this article, the authors compute the elastic displacements and stresses in a homogeneous, two-dimensional half-space driven by a pressurized crack that may breach the surface.

TL;DR: In this paper, the authors examined relations between different magnitude scales with an emphasis on the difference in the period of the waves used for the magnitude determination, and used the moment magnitude to quantify both shallow and deep earthquakes.

TL;DR: In this article, a model for the faulting of rocks in a three-dimensional strain field is derived and the orientations of these theoretically preferred faults are derived, and compared with the experimental results of Part I (Reches and Dieterich, 1983).

TL;DR: A review of the fundamental flow properties and processes in experimentally deformed natural and synthetic halite single crystals and polycrystalline aggregates is presented in this article, where a representative steady-state flow law determined for natural aggregates and maximum natural deviatoric stresses deduced from subgrain sizes are applied briefly to considerations of creep in waste repositories and of salt dome dynamics.

TL;DR: In this paper, six stages of crenulation cleavage development during a single deformation event (D2) can be recognized in both matrix and porphyroblast inclusion trails in the Robertson River Formation, N.E. Australia.

TL;DR: In this article, a model of seismic coupling is proposed, where the horizontal compressive stress between the two plates is proportional to the ratio of the summed asperity area to the total area of the contact surface.

TL;DR: In this paper, an analysis of crack-sealure fiber growth mechanisms has shown two important implications of the crackseal process for the interpretation of microstructures in low-grade metamorphic rocks: 1) the ability of fibre growth to track the incremental separation history of crack walls depends on details of the nucleation and growth mechanisms.

TL;DR: In this article, conditions favoring this sort of tectonic response are shown to be 1) a high angle of oblique convergence, 2) a low angle of subduction, and 3) relative thermal softening of the magmatic arc.

TL;DR: In this paper, the main central thrust zone is divided geologically by the Main Central Thrust zone into the underlying Midland metasediment zone (Lower Himalayas) in the south and the overlying Himalayan gneiss zone (Higher Himalaysas) (HG-HMS), and the latter zone consists of high-grade crystalline rocks with a north-dipping homoclinal structure and is further overlain by the Tethys Himalayis, composed of non- or slightly metamorphosed Tethyan sediments.

TL;DR: In this article, a regional compilation of published and unpublished gravity data for Central Africa is presented and reveals the presence of a major rift system, called here, the Central African Rift System, which is considered to be structurally similar to the early stages of passive margin development and thus reflect more closely the initial processes of continental fragmentation than the structures associated with rifting in East Africa.

TL;DR: In this article, the authors used an extensive seismic refraction survey of the northern Mississippi Embayment to support a rifting hypothesis and showed that the seafloor structure of the Mississippi is characterized by six primary layers that correspond geologically to unconsolidated Mesozoic and Tertiary sediments (1.8 km/s), Paleozoic carbonate and clastic sedimentary rocks (5.9 km/m), a low-velocity layer, crystalline upper crust, lower crust, modified lower crust and mantle), and a 7.3 km/

TL;DR: In this article, it was shown that it takes 50-75 million years to thin the continental lithosphere to the base of the crust; the long length of time required appears to rule out this lithospheric erosion mechanism as a viable mechanism for complete lithosphere thinning.

TL;DR: In this paper, two main clear-cut groups of granulites of the Variscan median Europe are distinguished based on differences in structural, petrological and radiometric features: Group I comprises lenses of eclogite-granulite scattered in the internal zones of the Hercynian belt; Group II includes granulitic slices related to deep-seated Alpine lineaments and xenoliths scavenged by recent volcanoes.

TL;DR: In this paper, it is suggested that the grabens provide void spaces within the surface of the subducting plate, below the plane of subduction, into which the trench sediments are tectonically displaced and thus subducted.

TL;DR: In this paper, the dependence of the number of sets of faults and their orientation on the intermediate strain axis is investigated through polyaxial tests, reported here, and theoretical analysis, reported in an accompanying paper.

TL;DR: In this article, the authors proposed that the deformational structures were formed by earthquake-induced liquefaction and interpreted them to represent five recent seismic events of probable irregular recurrence interval.

TL;DR: In this article, the authors proposed a method to estimate the strain from the preferred orientation of platy phyllosilicate grains, taking strain to be homogeneous from a pragmatic point of view, although numerous theoretical objections to this procedure can be and have been raised.

TL;DR: In this article, the authors made a study of about 700 dykes in eastern Iceland and found that the average thickness of the dykes is about 4.1 m, and the thickness does not change notably along the Alftafjordur swarm.

TL;DR: Rubie et al. as mentioned in this paper showed that reaction-enhanced ductility occurs when reaction boundaries are crossed during underthrusting rather than during the thermal readjustments of a perturbed geotherm following crustal thickening, or during uplift.

TL;DR: In this article, the authors investigated the space-time distribution of earthquakes along the Himalayan plate boundary with a view to discerning fluctuations in seismicity rates associated with great earthquakes, the possibilities of epicentre migration and gaps in seismic activity.

TL;DR: Urai et al. as mentioned in this paper used water assisted dynamic recrystallization and weakening in polycrystalline bischofite to solve the problem of weakening of bischoffite.

TL;DR: In this paper, the implications of heat flow data available from five major Cenozoic continental rift systems for the processes of continental rifting are discussed, and simple thermal models of lithospheric thinning which predict uplift are used to further constrain the thermal processes in the lithosphere during rifting.

TL;DR: The relationship among the anisotropy of magnetic susceptibility, the finite strain and the characteristic remanent magnetization (ChRM) have been investigated in deformed red sediments from the Alpes Maritimes in southeast France.

TL;DR: For example, Anderson et al. as mentioned in this paper found that the fine-grained matrix of the San Gabriel cataclasite is composed of a mosaic of equidimensional, interlocking grains.

TL;DR: The Wologorong batholith as discussed by the authors has two gneissic foliations (S 1 ) and S 2 ) formed oblique (up to 30°) to S 1, in order to accommodate an imposed shear component of the strain in strongly deformed parts of the batholith.