Trench triple junction off Central Japan—preliminary results of French-Japanese 1984 Kaiko cruise, Leg 2     

Vincent Renard  Kazuaki Nakamura  Jacques Angelier  Jacques Azema  Jacques Bourgois  Christine Deplus  Kantaro Fujioka  Yozo Hamano  Philippe Huchon  Hajimu Kinoshita  Pierre Labaume  Yujiro Ogawa  Tetsuzo Seno  Akira Takeuchi  Manabu Tanahashi  Akinori Uchiyama  Jean-Louis Vigneresse 《Earth and Planetary Science Letters》1987,83(1-4)

Leg 2 of the French-Japanese 1984 Kaiko cruise has surveyed the trench triple junction off central Japan, where the Japan, Izu-Bonin and Sagami Trenches intersect. The Izu-Bonin Trench is deeper than the Japan Trench and filled by a thick turbiditic series. Its anomalous depth is explained by the westward retreat of the edge of the northwestward moving Philippine Sea plate. On the contrary to what happens in the Japan Trench, horst and graben structures of the Pacific plate obliquely enters the Izu-Bonin Trench, suggesting that the actual boundary between these two trenches is located to the north of the triple junction. The inner wall of the Izu-Bonin Trench is characterized in the triple junction area by a series of slope basins whose occurrence is related to the dynamics of this area. The northernmost basin is overthrust by the edge of the fore-arc area of the Northeast Japan plate. The plate boundary is hardly discernible further east, which makes it impossible to locate precisely the triple junction itself. These features suggest that large intra-plate deformation occurs there due to the interaction of the plates involved in the triple junction and the weak mechanical strength of the wedge-shaped margin of the overriding plates.  相似文献   

Intense hydrothermal activity at the axis of the east pacific rise near 13°N: Sumbersible witnesses the growth of sulfide chimney     

R. Hekinian  J. Francheteau  V. Renard  R. D. Ballard  P. Choukroune  J. L. Cheminee  F. Albarede  J. F. Minster  J. L. Charlou  J. C. Marty  J. Boulegue 《Marine Geophysical Researches》1983,6(1):1-14

A submersible study of a fast spreading (12 cm yr^-1) Mid-Ocean ridge segment (East Pacific Rise near 12°50′ N) led to the discovery of intense hydrothermal activity. Twenty four sites with active vents and sixty inactive hydrothermal deposits were found within a narrow graben averaging about 300 m in width along a 20 km long segment of the ridge crest. The graben is floored with fresh basaltic sheet flows including collapsed pits or lava lake structures. From both deep towed camera stations and manned submersible observations, it is estimated that the average spacing between the ridge axis hydrothermal deposits averaging in size 10–50 m in diameter lies between 100 to 200 m. The hydrothermal deposits found in the central graben are believed to have formed rapidly (on the order of a few decades). Detailed investigations of one active site have enabled us to witness the growth of an active chimney which increased its height by 40 cm in 5 days i.e. 8 cm per day. Extensive hydrothermal deposits were discovered on an off-axis seamount located 6 km East of the ridge axis. The hydrothermal deposits found on both the ridge axis and on the seamount are similar in composition and consist essentially of zinc, copper and iron mineral phases. Chemical studies conducted on the venting fluids (320°C) showed that the concentration of the dissolved major metal ions (Fe, Mn, and Zn) is about 0.10–0.13 gl^-1. If we accept an average flow rate of 10ls^-1 based on visual observations the mass of metallic products spewing out from an active chimney must be about 100 kg per day.  相似文献   

A survey of groundwater quality in Tulum region,Yucatan Peninsula,Mexico     

Renaud Saint-Loup  Théo Felix  Axaycatl Maqueda  Arnulf Schiller  Philippe Renard 《Environmental Earth Sciences》2018,77(18):644

The city of Tulum, in the state of Quintana Roo (Mexico) depends almost exclusively on groundwater for water supply. The groundwater is exploited from a coastal aquifer which contains a karst network that is considered as one of the largest ones on earth. Given the nature of karst aquifers, the whole area is very sensitive to contaminants and bacteria transport, because flow paths, residence time and degradation rates differ significantly from what can be observed in the porous aquifer. The present study focuses on isotopes (¹⁸O and ²H), dissolved ions’ concentration and Escherichia coli (E. coli). The result of our survey points out the anthropic impact on groundwater quality. Furthermore, the chloride concentrations illustrate the influence of seawater mixing and geological heterogeneity over the study area. Due to an exponential growth of the tourism industry, the needs in terms of water supply and water treatment increase significantly. Tulum is a coastal city, facing a coral reef and is bordered by the Sian Ka’an biosphere reserve, therefore, an environmental issue is added to the sanitary issue, both being the basis of the local economic development. Our results show that E. coli remains a major issue, as several samples tested were contaminated, in particular those in the city center. Ions’ survey shows an anthropic impact through nitrate, phosphate and fluoride concentrations, but the obtained values are not alarming. Considering the saline intrusion, chloride concentrations indicate that the area below the Tulum city center seems to be less permeable (and maybe less karstified) than the surrounding areas, as groundwater is less subject to seawater mixing than other sampling sites at similar distance to the coast.  相似文献   

Integrating aerial geophysical data in multiple-point statistics simulations to assist groundwater flow models     

Neil E. M. Dickson  Jean-Christophe Comte  Philippe Renard  Julien A. Straubhaar  Jennifer M. McKinley  Ulrich Ofterdinger 《Hydrogeology Journal》2015,23(5):883-900

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A pseudo-genetic stochastic model to generate karstic networks     

Andrea Borghi  Philippe Renard  Sandra Jenni 《Journal of Hydrology》2012

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Characterization of Fault Roughness at Various Scales: Implications of Three-Dimensional High Resolution Topography Measurements     

Thibault Candela  François Renard  Michel Bouchon  Alexandre Brouste  David Marsan  Jean Schmittbuhl  Christophe Voisin 《Pure and Applied Geophysics》2009,166(10-11):1817-1851

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Random partitioning and adaptive filters for multiple-point stochastic simulation     

Mansoureh?SharifzadehlariEmail authorView author&#;s OrcID profile  Nader?Fathianpour  Philippe?Renard  Rassoul?Amirfattahi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(5):1375-1396

Multiple-point geostatistical simulation is used to simulate the spatial structures of geological phenomena. In contrast to conventional two-point variogram based geostatistical methods, the multiple-point approach is capable of simulating complex spatial patterns, shapes, and structures normally observed in geological media. A commonly used pattern based multiple-point geostatistical simulation algorithms is called FILTERSIM. In the conventional FILTERSIM algorithm, the patterns identified in training images are transformed into filter score space using fixed filters that are neither dependent on the training images nor on the characteristics of the patterns extracted from them. In this paper, we introduce two new methods, one for geostatistical simulation and another for conditioning the results. At first, new filters are designed using principal component analysis in such a way to include most structural information specific to the governing training images resulting in the selection of closer patterns in the filter score space. We then propose to combine adaptive filters with an overlap strategy along a raster path and an efficient conditioning method to develop an algorithm for reservoir simulation with high accuracy and continuity. We also combine image quilting with this algorithm to improve connectivity a lot. The proposed method, which we call random partitioning with adaptive filters simulation method, can be used both for continuous and discrete variables. The results of the proposed method show a significant improvement in recovering the expected shapes and structural continuity in the final simulated realizations as compared to those of conventional FILTERSIM algorithm and the algorithm is more than ten times faster than FILTERSIM because of using raster path and using small overlap specially when we use image quilting.  相似文献   

Estimating the uncertainty of video-based flow velocity and discharge measurements due to the conversion of field to image coordinates     

Jérôme Le Coz  Benjamin Renard  Vincent Vansuyt  Magali Jodeau  Alexandre Hauet 《水文研究》2021,35(5):e14169

Video-based hydrometry continues to develop for contactless discharge measurements, automated flood gauging stations and the use of crowd-sourced flood videos for discharge reconstruction. Irrespective of the velocimetry algorithm used (LSPIV, STIV, PTV…), orthorectification of the images is necessary beforehand, so that each pixel has the same known physical size. Most times, the orthorectification transformation is a plane-to-plane projection from the water surface to the camera sensor. Two approaches are typically used to compute the coefficients of this transformation: their calibration from ground reference points (GRPs) with known image and real-world coordinates (“implicit calibration”) or their calculation from the values of the intrinsic (focal length, sensor size) and extrinsic (position, angles) parameters of the camera (“explicit calibration”). In this paper, we develop a Bayesian method which makes it possible to combine the implicit and explicit approaches in a probabilistic framework. The Bayesian approach can be used from situations suitable for the implicit approach (plenty of GRPs) to situations propitious to the explicit approach (well-known camera parameters). The method is illustrated using synthetic views of a typical streamgauging scene with known true values of the parameters and GRP coordinates. We show that combining observational and prior information is generally beneficial to get precise estimates. Further tests carried out with a real scene of the Arc River at Randens, France, in flood conditions illustrate the impact of the number, uncertainty and spatial distribution of GRPs on the final uncertainty of flow velocity and discharge.  相似文献   

Effect of Surface Morphology on the Dissipation During Shear and Slip Along a Rock–Rock Interface that Contains a Visco-elastic Core     

Luiza Angheluta  Thibault Candela  Joachim Mathiesen  François Renard 《Pure and Applied Geophysics》2011,168(12):2335-2344

High resolution topography measurements of the Vuache–Sillingy fault (Alps, France) reveal a characteristic roughness of the fault zone. We investigate the effect of roughness on the rheology of a planar shear configuration by using a model system consisting of a visco-elastic layer embedded into a rigid solid. The model is discussed in the context of several geological cases: a damage fault zone, a fault smeared with a clay layer, and a shear zone with strain weakening. Using both analytical approaches and finite element simulations, we calculate to linear order the relation between wall roughness and the viscous dissipation in the fault zone as well as the average shear rate.  相似文献   

Imaging the heart of astrophysical objects with optical long-baseline interferometry     

J.-P. Berger  F. Malbet  F. Baron  A. Chiavassa  G. Duvert  M. Elitzur  B. Freytag  F. Gueth  S. H?nig  J. Hron  H. Jang-Condell  J.-B. Le Bouquin  J.-L. Monin  J. D. Monnier  G. Perrin  B. Plez  T. Ratzka  S. Renard  S. Stefl  E. Thiébaut  K. R. W. Tristram  T. Verhoelst  S. Wolf  J. Young 《Astronomy and Astrophysics Review》2012,20(1):1-55

The number of publications of aperture-synthesis images based on optical long-baseline interferometry measurements has recently increased due to easier access to visible and infrared interferometers. The interferometry technique has now reached a technical maturity level that opens new avenues for numerous astrophysical topics requiring milli-arcsecond model-independent imaging. In writing this paper our motivation was twofold: (1) review and publicize emblematic excerpts of the impressive corpus accumulated in the field of optical interferometry image reconstruction; (2) discuss future prospects for this technique by selecting four representative astrophysical science cases in order to review the potential benefits of using optical long-baseline interferometers. For this second goal we have simulated interferometric data from those selected astrophysical environments and used state-of-the-art codes to provide the reconstructed images that are reachable with current or soon-to-be facilities. The image-reconstruction process was ??blind?? in the sense that reconstructors had no knowledge of the input brightness distributions. We discuss the impact of optical interferometry in those four astrophysical fields. We show that image-reconstruction software successfully provides accurate morphological information on a variety of astrophysical topics and review the current strengths and weaknesses of such reconstructions. We investigate how to improve image reconstruction and the quality of the image possibly by upgrading the current facilities. We finally argue that optical interferometers and their corresponding instrumentation, existing or to come, with six to ten telescopes, should be well suited to provide images of complex sceneries.  相似文献