Modelling the Mixing Function to Constrain Coseismic Hydrochemical Effects: An Example from the French Pyrénées     

Jean-Paul Toutain  Margot Munoz  Jean-Louis Pinaud  Stéphanie Levet  Matthieu Sylvander  Alexis Rigo  Jocelyne Escalier 《Pure and Applied Geophysics》2006,163(4):723-744

Groundwater coseismic transient anomalies are evidenced and characterized by modelling the mixing function F characteristic of the groundwater dynamics in the Ogeu (western French Pyrénées) seismic context. Investigations of water-rock interactions at Ogeu indicate that these mineral waters from sedimentary environments result from the mixing of deep waters with evaporitic signature with surficial karstic waters. A 3-year hydrochemical monitoring of Ogeu springwater evidences that using arbitrary thresholds constituted by the mean ± 1 or 2σ, as often performed in such studies, is not a suitable approach to characterize transient anomalies. Instead, we have used a mixing function F calculated with chemical elements, which display a conservative behavior not controlled by the precipitation of a mineral phase. F is processed with seismic energy release (E_s) and effective rainfalls (R). Linear impulse responses of F to E_s and R have been calculated. Rapid responses (10 days) to rainwater inputs are evidenced, consisting in the recharge of the shallow karstic reservoir by fresh water. Complex impulse response of F to microseismic activity is also evidenced. It consists in a 2-phase hydrologic signal, with an inflow of saline water in the shallow reservoir with a response delay of 10 days, followed by an inflow of karstic water with a response delay of 70 days, the amount being higher than the saline inflow. Such a process probably results from changes in volumetric strain with subsequent microfracturation transient episodes allowing short inflow of deep salted water in the aquifer. This study demonstrates that groundwater systems in such environments are unstable systems that are highly sensitive to both rainfall inputs and microseismic activity. Impulse responses calculation of F to E_s is shown to be a powerful tool to identify transient anomalies. Similar processing is suggested to be potentially efficient to detect precursors of earthquakes when long time-series (5 years at least) are available in areas with high seismicity.  相似文献   

利用MODIS和ASAR资料估算青藏高原念青唐古拉山脉地区冰雪范围及厚度   总被引：3，自引：1，他引：3  

文军  Dai Mo  王致君  张堂堂  Humbert Louis 《冰川冻土》2006,28(1):54-61

利用可见光和微波卫星遥感资料分析了青藏高原念青唐古拉山脉地区冰雪范围和厚度的季节变化.结果表明:青藏高原念青唐古拉山脉地区冰雪范围的季节变化非常明显,2003年4月上旬、5月中旬、7月下旬和9月下旬的冰雪范围分别占选定研究区域的28.9%、69.9%、11.6%和14.7%.在选定的西布冰川区域,由微波遥感得到的冰雪厚度季节变化也非常明显,5月份厚度的数值最大,7月份最小.由于主动微波观测受地面高程、地形和夏季冰雪融化等因素的影响比较大,主动微波遥感在大面积估算冰雪厚度还有一定困难,有待将来作进一步的深入研究.  相似文献   

Variability of the Gravity-to-Height Ratio Due to Surface Loads     

Caroline de Linage  Jacques Hinderer  Jean-Paul Boy 《Pure and Applied Geophysics》2009,166(8-9):1217-1245

We study the ratio between the gravity variation and vertical displacement on the surface of a self-gravitating earth model when a surface load is applied. We adopt a theoretical and numerical point of view, excluding any observations. First, we investigate the spectral behavior of the ratio of the harmonic components of the gravity variation and vertical displacement. Then, we model the gravity-to-height ratio for different surface loads (continental hydrology, atmospheric pressure, ocean tides) using outputs of global numerical models in order to relate the predicted spatial values to theoretical mean values deduced from the spectral domain. For locations inside loaded areas, the ratio is highly variable because of the Newtonian attraction of the local masses and depends on the size of the load. For the hydrological loading (soil moisture and snow), the mean ratio over the continents is  ?0.87 μGal mm^?1, but increases with decreasing size of the river basins. For the atmospheric loading, assuming an inverted-barometer response of the ocean, the ratio is positive, with larger values for high latitudes (0.49 μGal mm^?1)—particularly on the coasts—than for lower latitudes (0.30 μGal mm^?1). The ratio, however, is much less variable outside the loaded areas: in desert areas such as the Sahara and Arabia, its mean value is  ?0.28 μGal mm^?1. For the ocean tidal loading, we find a mean ratio of  ?0.26 μGal mm^?1 over the continents for the diurnal tidal waves. Both results are close to the theoretical mean value of  ?0.26 μGal mm^?1 combining elastic and remote attraction contributions.  相似文献   

大河流域综合发展的比较研究:以长江和罗讷河为例     

刘慧  蔡宗夏  Thierry Sanjuan 《地理学报(英文版)》2006,16(3):378-382

1 Research background The globalization in process challenges our traditional way of looking at territories. New regional entities are emerging at sub-continental level as it is the case in Western and Central Europe through the growing assertion of Europ…  相似文献   

The current status of deep SCUBA surveys     

Ian Smail  Rob Ivison  Andrew Blain  Jean-Paul Kneib 《Astrophysics and Space Science》1999,266(1-2):279-284

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Determination of the gravimetric factor at the Chandler period from Earth orientation data and superconducting gravimetry observations   总被引：1，自引：0，他引：1  

Sylvain Loyer  Jacques Hinderer  & Jean-Paul Boy 《Geophysical Journal International》1999,136(1):1-7

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Swiss and Alpine geologists between two tectonic revolutions. Part 1: from the discovery of nappes to the hypothesis of continental drift     

Jean-Paul Schaer 《Swiss Journal of Geoscience》2010,103(3):503-522

At the advent of the twentieth century, geologists believed that folded continental mountain chains like the Alps were due to horizontal compression, resulting from contractions of the Earth’s crust as it cooled. In 1918, Albert Heim defended this point of view and illustrated it with a geological section across Switzerland. In 1915, however, and in short notes as early as 1912, Alfred Wegener in Die Entstehung der Kontinente und Ozeane (The Origin of Continents and Oceans) proposed that mountains were the result of collisions between light continents drifting and floating on denser formations of the Earth’s interior, also present at the bottom of the oceans. Before this (1906), Otto Ampferer had already proposed the association of folds with active movements of material inside the Earth. Wegener used numerous morphological, geological, and gravimetric data to justify his theory. He was innovative in his successful use of paleogeographic and paleoclimatologic reconstitutions. Although very popular, his theory only received reserved approval from the active scientific community. Alpine geologists found it too audacious and too far removed from the field data. In the first critical analysis written in French (1922), Elie Gagnebin welcomed it as a working hypothesis, but was very reserved regarding the arguments of a geophysicist who, in his opinion, was not sufficiently versed in structural geology. In contrast, Emile Argand integrated Wegener’s theory into his conception of the evolution of the Alps already in 1916. At that time, he judged the Alpine orogeny to have been the result of permanent compression and proposed that its whole history had been dominated by what he called embryonic tectonics, a compressional concept which he illustrated so admirably that it had an incomparable and lasting success. However, he himself abandoned it in his major work, La Tectonique de l’Asie (The Tectonics of Asia), in favour of an evolution that first originated in an extension regime, finally leading to the splitting of the continental crust, with local emergence of basic rocks, constituting the bottom of new oceanic floors. It is at the slope of these continental margins, and at their foot, that geosynclines are formed by the large accumulation of sediments transported by submarine slumping. During the following compressive stage, slices of basic ocean floor are transported upwards between overlapping continental masses, forming extensive ophiolitic zones. Although admired for his enormous accomplishment, La Tectonique de l’Asie remained ignored for its most innovative propositions, which clearly foreshadow plate tectonics. After this work, Argand practically abandoned geology. His last publication (1934), Guide géologique de la Suisse: la zone pennique (Geological Guide to Switzerland: the Pennine Zone), revived his argument of the early evolution of the geosyncline in a context of extension, followed by thrusts involving the ocean floor. Unfortunately, the concept had no greater success than at its first appearance.  相似文献   

Herschel SPIRE FTS relative spectral response calibration     

Trevor Fulton  Rosalind Hopwood  Jean-Paul Baluteau  Dominique Benielli  Peter Imhof  Tanya Lim  Nanyao Lu  Nicola Marchili  David Naylor  Edward Polehampton  Bruce Swinyard  Ivan Valtchanov 《Experimental Astronomy》2014,37(2):381-395

Herschel/SPIRE Fourier transform spectrometer (FTS) observations contain emission from both the Herschel Telescope and the SPIRE Instrument itself, both of which are typically orders of magnitude greater than the emission from the astronomical source, and must be removed in order to recover the source spectrum. The effects of the Herschel Telescope and the SPIRE Instrument are removed during data reduction using relative spectral response calibration curves and emission models. We present the evolution of the methods used to derive the relative spectral response calibration curves for the SPIRE FTS. The relationship between the calibration curves and the ultimate sensitivity of calibrated SPIRE FTS data is discussed and the results from the derivation methods are compared. These comparisons show that the latest derivation methods result in calibration curves that impart a factor of between 2 and 100 less noise to the overall error budget, which results in calibrated spectra for individual observations whose noise is reduced by a factor of 2–3, with a gain in the overall spectral sensitivity of 23 % and 21 % for the two detector bands, respectively.  相似文献   

A Hubble Space Telescope lensing survey of X-ray luminous galaxy clusters – IV. Mass, structure and thermodynamics of cluster cores at z= 0.2     

Graham P. Smith  Jean-Paul Kneib  Ian Smail  Pasquale Mazzotta  Harald Ebeling  Oliver Czoske 《Monthly notices of the Royal Astronomical Society》2005,359(2):417-446

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法国罗纳河及其流域整治     

让-保罗·布拉瓦尔  蔡宗夏 《世界地理研究》2015,(1):11-18

罗纳河历史上曾经是欧洲的一条典型的"野性"河流,洪水汹涌,桀骜不驯。后来,它又成了一条为法国近代的工业革命和现代经济发展作出重大贡献的"驯服"的河流。在500多公里的河段,建造了20多座水电站,为河流水电站梯级开发之"世界之最"。然而,自从1980年代以来,随着法国能源政策转向大力发展核电,水电站梯级开发时代的结束,环境保护的呼声日益高涨,罗纳河的整治逐渐进入以自然生态环境的恢复和保护为中心的持续发展时代。人们开始拆除水坝和河堤,恢复河漫滩湿地,等等。在这人与河流复杂的相互关系的历史中,河流流域整治的观念,政策都发生了巨大的变化,整治的科技手段也有了很大的进步。罗纳河流域整治以"健康河流"和"河流健康"为中心的发展战略,为中国河流流域整治提供了值得借鉴的经验。  相似文献