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61.
新型超导重力仪已被证实在频率低于1 mHz的情况下优于最好的地震仪STS-1, 因而新型超导重力仪可作为极低噪音的地震仪, 观测长周期地球自由振荡. 具有良好窄带频率响应的小波滤波器非常有助于消除大气压波动对重力变化的影响. 用小波滤波器处理2004年12月26日苏门答腊大地震后的超导重力仪的观测数据, 清楚地检测到了1.5 mHz以下, 除0T5, 0T7, 1T1外所有的环形自由振荡的耦合现象, 并检测到了环形自由振荡1T2, 1T3的耦合现象. 此外, 还利用单台超导重力仪的观测数据清楚地检测到了球形自由振荡2S1的3个分裂谱峰. 相似文献
62.
We have performed holographic interferometry measurements of the dissolution of the (0 1 0) plane of a cleaved gypsum single crystal in pure water. These experiments have provided the value of the dissolution rate constant k of gypsum in water and the value of the interdiffusion coefficient D of its aqueous species in water. D is 1.0 × 10−9 m2 s−1, a value close to the theoretical value generally used in dissolution studies. k is 4 × 10−5 mol m−2 s−1. It directly characterizes the microscopic transfer rate at the solid-liquid interface, and is not an averaged value deduced from quantities measured far from the surface as in macroscopic dissolution experiments. It is found to be two times lower than the value obtained from macroscopic experiments. 相似文献
63.
The Zagros fold-and-thrust belt of SW-Iran is among the youngest continental collision zones on Earth. Collision is thought to have occurred in the late Oligocene–early Miocene, followed by continental shortening. The High Zagros Belt (HZB) presents a Neogene imbricate structure that has affected the thick sedimentary cover of the former Arabian continental passive margin. The HZB of interior Fars marks the innermost part of SE-Zagros, trending NW–SE, that is characterised by higher elevation, lack of seismicity, and no evident active crustal shortening with respect to the outer (SW) parts. This study examines the brittle structures that developed during the mountain building process to decipher the history of polyphase deformation and variations in compressive tectonic fields since the onset of collision. Analytic inversion techniques enabled us to determine and separate different brittle tectonic regimes in terms of stress tensors. Various strike–slip, compressional, and tensional stress regimes are thus identified with different stress fields. Brittle tectonic analyses were carried out to reconstruct possible geometrical relationships between different structures and to establish relative chronologies of corresponding stress fields, considering the folding process. Results indicate that in the studied area, the main fold and thrust structure developed in a general compressional stress regime with an average N032° direction of σ1 stress axis during the Miocene. Strike–slip structures were generated under three successive strike–slip stress regimes with different σ1 directions in the early Miocene (N053°), late Miocene–early Pliocene (N026°), and post-Pliocene (N002°), evolving from pre-fold to post-fold faulting. Tensional structures also developed as a function of the evolving stress regimes. Our reconstruction of stress fields suggests an anticlockwise reorientation of the horizontal σ1 axis since the onset of collision and a significant change in vertical stress from σ3 to σ2 since the late stage of folding and thrusting. A late right-lateral reactivation was also observed on some pre-existing belt-parallel brittle structures, especially along the reverse fault systems, consistent with the recent N–S plate convergence. However, this feature was not reflected by large structures in the HZB of interior Fars. The results should not be extrapolated to the entire Zagros belt, where the deformation front has propagated from inner to outer zones during the younger events. 相似文献
64.
Aspects of GLONASS Carrier-Phase Differencing 总被引:2,自引:0,他引:2
65.
Jacques Lévy 《GeoJournal》1998,46(4):279-283
The paper initially describes some of the most important historical processes that have conditioned France's geopolitical position in the contemporary world. It discusses the current changes in France's geopolitics as a changing reality of international relations and as a changing discourse of scholars and experts, that reflects those real world changes. The paper focuses on French politics in Africa and on France's policy in Europe after the end of the Cold War. In Africa the French post-colonial empire with its close ties between domestic regimes, French business interests and the French state becomes unsustainable after the bipolar rivalry has been suspended. In Europe French policy can no longer be presented as either an independent view among a series of others (Europe des patries) nor as a successful effort to press French views by way of a larger European entity. The paper presents an overview of geopolitical literature written in France as a reflection of these conditions. 相似文献
66.
Jacques Boulgue 《Journal of Geochemical Exploration》1981,15(1-3)
The interaction of water and sulfide minerals yields dissolved species which can be utilized to trace back the presence of sulfide minerals and associated minerals. Computer modeling and laboratory and field results show that the most characteristic dissolved species are hydrogen sulfide (H2S, HS−), polysulfide ions (Sn2−) and thiosulfate (S2O32−), derived from the hydrolysis of sulfide minerals. Typical concentration ranges are: 10−5 – 10−7 mole/l for hydrogen sulfide, 10−6 – 10−9 mole/l for polysulfides and 10−5 – 10−8 mole/l for thiosulfate. The chemical reactivity of these species at contact with air makes them difficult to assess unless determined immediately after sampling.These sulfur species can be determined rapidly and accurately in field conditions by simultaneous titration with mercuric chloride employing an Ag/Ag2S electrode for the determination of the end points.The application to ore exploration is exemplified by the results of the research on roll-type uranium deposits in the southwest of France. 相似文献
67.
68.
Jacques Fabriès 《Contributions to Mineralogy and Petrology》1979,69(4):329-336
An empirical calibration of the spinel-olivine geothermometer (Evans and Frost, 1975) is attempted and applied to parageneses of lherzolitic rocks. In ultramafic complexes, most of the derived temperature estimates range between 700 ° and 850 °C, and appear generally lower than those given by other geothermometers, based upon Ca or Al contents of coexisting pyroxenes. A comparison of the different thermometric data in two well studied occurrences, the Ronda ultramafic complex and the San Carlos xenolith field, suggests that differential rates of diffusion and recrystalization may account for the large range of temperatures (between 700 ° and 1200 °C) determined by various mineral geothermometers in peridotites. The equilibrium exchange of Mg and Fe between spinel and olivine would be the fastest one and would continue effectively during the cooling down to relatively low temperatures, while other exchange reactions used as geothermometers in peridotites, like partitioning of Ca and Al in coexisting pyroxenes, are blocked at higher temperatures. 相似文献
69.
Xavier Le Pichon Jacques Angelier Jean Aubouin Nicolas Lyberis Serge Monti Vincent Renard Henri Got Ken Hsu¨ Yossi Mart Jean Mascle Drummond Matthews Dimitri Mitropoulos Pandelis Tsoflias Georges Chronis 《Earth and Planetary Science Letters》1979,44(3):441-450
Preliminary results of a multi-narrow beam survey of the Hellenic trench system, in the Eastern Mediterranean, are presented. The southwestern Ionian branch is divided in small basins, partly filled with Pleistocene sediments. The morphology suggests that the basins are deformed by a compressional stress acting roughly perpendicularly to the trench along N50°E. This direction is the direction of the regional slip vector of the shallow thrust-type earthquakes. The structure of the southeastern Pliny-Strabo branch is quite different. Narrow en-e´chelon slots, oriented N40°E, have been mapped within the main troughs oriented N60°E. The regional earthquake slip vector is also oriented along N40°E. We conclude that the Hellenic trench system is an active subduction system, dominated by thrust along the Ionian branch and by transform motion along the Pliny-Strabo branch. 相似文献
70.
Determination of the mean principal directions of stresses for a given fault population 总被引:8,自引:0,他引:8
Jacques Angelier 《Tectonophysics》1979,56(3-4)
New methods of determination of stress axes, from field measurements of the orientations of faults and slickenslides, are discussed. Results show that the approximation which assumes that relative motion along any fault is controlled by a single common mean stress tensor is valid. 相似文献