共查询到20条相似文献，搜索用时 609 毫秒
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Global patterns of azimuthal anisotropy and deformations in the continental mantle 总被引：23，自引：0，他引：23
L. P. Vinnik L. I. Makeyeva A. Milev A. Yu. Usenko 《Geophysical Journal International》1992,111(3):433-447
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C. Plattner R. Malservisi T. H. Dixon P. LaFemina G. F. Sella J. Fletcher F. Suarez-Vidal 《Geophysical Journal International》2007,170(3):1373-1380
We present a new surface velocity field for Baja California using GPS data to test the rigidity of this microplate, calculate its motion in a global reference frame, determine its relative motion with respect to the North American and the Pacific plates, and compare those results to our estimate for Pacific–North America motion. Determination of Pacific Plate motion is improved by the inclusion of four sites from the South Pacific Sea Level and Climate Monitoring Project. These analyses reveal that Baja California moves as a quasi-rigid block but at a slower rate in the same direction, as the Pacific Plate relative to North America. This is consistent with seismic activity along the western edge of Baja California (the Baja California shear zone), and may reflect resistance to motion of the eastern edge of the Pacific Plate caused by the 'big bend' of the San Andreas fault and the Transverse Ranges in southern California. 相似文献
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Seismotectonics of the Cyprian Arc 总被引：1，自引：0，他引：1
Shimon Wdowinski Zvi Ben-Avraham Ronald Arvidsson Goran Ekström 《Geophysical Journal International》2006,164(1):176-181
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C. R. B. Lister 《Geophysical Journal International》1989,96(2):191-201
Summary. The elegant geometrical rules of plate tectonics do not allow for a gradual shift in plate motion directions, or the gradual, as opposed to sudden, cessation of subduction. At the scale of the small plates in the NE Pacific, imperfections in boundary processes have a large effect on the net torque on the plates, and heavily influence the evolution of the geometry. In this area, the rotation of the spreading directions and the diminution of true subduction along the southern Canadian coast has not occurred by the sudden switching of plate motions from one stable condition to another. Instead, it appears as if the dominant factor for the evolution is the resistance of the ocean floor to formation of new, smoothly slipping transform faults. Compressive deformation of even young lithosphere is not only mechanically unlikely, but is not helpful to the particular configurations found in this area. Instead, a migrating shear zone and an episode of highly en echelon spreading along a new axis nearly perpendicular to the present Juan de Fuca ridge have resulted: the present Sovanco ridge was never a transform fault. Neither is the Nootka fault a shear zone, but the locus of stretching between plates whose motions are congruent at the Juan de Fuca ridge, but diverge toward the continental margin. 相似文献
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Global heat budget, plate tectonics and climatic change 总被引：1，自引：0，他引：1
For the past 2000 Ma, the temperature of the Earth's surface has fluctuated around a mean similar to that of today, although individual locations have undergone long-term changes of ∼30°C at different times in different places. Water bodies absorb at least five times as much solar radiation as land surfaces, and ocean currents transport the excess heat absorbed in the tropics towards the poles. Changes in the distribution of land and sea due to plate tectonics explain the major temperature fluctuations (>25°C) around the globe in the last 350 Ma, and are first-order controls. Large-scale changes in ocean currents and thermohaline circulations are probably second-order controls (15–25°C). The Milankovitch orbital cycles are third-order controls producing variations in air temperature of the order of 10°C, while massive volcanic eruptions and changes in carbon dioxide are amongst the fourth-order controls producing minor perturbations (<5°C). The major climatic fluctuations are continuous but regional in effect and not global. Extraterrestrial factors may not cause major changes in climate when viewed from a geological perspective. 相似文献
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GPS constraints on Africa (Nubia) and Arabia plate motions 总被引：16，自引：0，他引：16
S. McClusky R. Reilinger S. Mahmoud D. Ben Sari A. Tealeb 《Geophysical Journal International》2003,155(1):126-138