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杨新军 《地理与地理信息科学》1997,(3)
中国导游翻译第一人王连义教授杨新军（北京大学城市与环境学系北京：１００８７１）王连义教授是我国著名的旅游接待管理、导游专家，现任国旅培训中心主任，曾任历届中国导游大赛裁判长。他在国旅总社从事旅游翻译、导游工作多年，对我国导游事业的兴起与发展作出了重大... 相似文献
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Continental collisions and seismic signature 总被引：6，自引：0，他引：6
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Rock as a critical-point system and the inherent implausibility of reliable earthquake prediction 总被引：1，自引：0，他引：1
P. C. Leary 《Geophysical Journal International》1997,131(3):451-466
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Variations in the crustal structure beneath western Turkey 总被引：6，自引：0，他引：6
Paul Saunders Keith Priestley & Tuncay Taymaz 《Geophysical Journal International》1998,134(2):373-389
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Magnetic fields originating from magnetized crustal rocks dominate the geomagnetic spectrum at wavelengths of 0.1–100 km. It is not known whether the magnetization is predominantly induced or remanent, and static surveys cannot discriminate between the two. Long‐running magnetic observatories offer a chance, in principle, of separating the two sources because secular variation leads to a change in the main inducing field, which in turn causes a change in the induced part of the short‐wavelength crustal field. We first argue that the induced crustal field, b I ( t ), is linearly related to the local core field, B ( t ), through a symmetric, trace‐free matrix A : b I ( t )= A B ( t ). We then subtract a core field model from the observatory annual means and invert the residuals for three components of the remanent field, b R ( t ), and the five independent elements of A . Applying the method to 20 European observatories, all of which have recorded for more than 50 years, shows that the most difficult task is to distinguish b R from the steady part of b I . However, for nine observatories a time‐dependent induced field fits the data better than a steady remanent field at the 99 per cent confidence level, suggesting the presence of a significant induced component to the magnetization. 相似文献
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Recent seismic field work has revealed high lower-crustal velocities under Ninetyeast Ridge, Indian Ocean, indicating the presence of crustal underplating ( Grevemeyer et al . 2000 ). We used results from Ocean Drilling Program (ODP) drill cores and cross-spectral analysis of gravity and bathymetric data to study the impact of the underplating body on the subsidence history and the mode of isostatic compensation along Ninetyeast Ridge. Compared with the adjacent Indian basin, the subsidence of Ninetyeast Ridge is profoundly anomalous. Within the first few millions of years after crustal emplacement the ridge subsided rapidly. Thereafter, however, subsidence slowed down significantly. The most reliable model of isostasy suggests loading of a thin elastic plate on and beneath the seafloor. Isostatic compensation of subsurface loading occurs at a depth of about 25 km, which is in reasonably good agreement with seismic constraints. Subsurface loading is inherently associated with buoyant forces acting on the lithosphere. The low subsidence may therefore be the superposition of cooling of the lithosphere and uplift due to buoyant material added at the base of the crust. A model including prolonged crustal growth in the form of subcrustal plutonism may account for all observations. 相似文献
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