Disrupting biogeochemical cycles - Consequences of damming   总被引：12，自引：0，他引：12  

Gabriela Friedl  Alfred Wüest 《Aquatic Sciences - Research Across Boundaries》2002,64(1):55-65

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Textural evidence for recent co-seismic circulation of fluids in the Nojima fault zone, Awaji island, Japan     

Anne-Marie Boullier  Koichiro Fujimoto  Tomoyuki Ohtani  Gabriela Roman-Ross  ric Lewin  Hisao Ito  Philippe Pezard  Benoît Ildefonse 《Tectonophysics》2004,378(3-4):165

The Hirabayashi borehole (Awaji Island, Japan) was drilled by the Geological Survey of Japan (GSJ) 1 year after the Hyogo-ken Nanbu (Kobe) earthquake (1995, M_JMA=7.2). This has enabled scientists to study the complete sequence of deformation across the active Nojima fault, from undeformed granodiorite to the fault core. In the fault core, different types of gouge and fractures have been observed and can be interpreted in terms of a complex history of faulting and fluid circulation. Above the fault core and within the hanging wall, compacted cataclasites and gouge are cut by fractures which show high apparent porosity and are filled by 5–50 μm euhedral and zoned siderite and ankerite crystals. These carbonate-filled fractures have been observed within a 5.5-m-wide zone above the fault, but are especially abundant in the vicinity (1 m) of the fault. The log-normal crystal size distributions of the siderite and ankerite suggest that they originated by decaying-rate nucleation accompanied by surface-controlled growth in a fluid saturated with respect to these carbonates. These carbonate-filled fractures are interpreted as the result of co-seismic hydraulic fracturing and upward circulation of fluids in the hanging wall of the fault, with the fast nucleation of carbonates attributed to a sudden fluid or CO₂ partial pressure drop due to fracturing. The fractures cut almost all visible structures at a thin section scale, although in some places, the original idiomorphic shape of carbonates is modified by a pressure-solution mechanism or the carbonate-filled fractures are cut and brecciated by very thin gouge zones; these features are attributed to low and high strain-rate mechanisms, respectively. The composition of the present-day groundwater is at near equilibrium or slightly oversaturated with respect to the siderite, calcite, dolomite and rhodochrosite. Taken together, this suggests that these fractures formed very late in the evolution of the fault zone, and may be induced by co-seismic hydraulic fracturing and circulation of a fluid with a similar composition to the present-day groundwater. They are therefore potentially related to recent earthquake activity (<1.2 Ma) on the Nojima fault.  相似文献   

The impact of heat waves on surface urban heat island and local economy in Cluj-Napoca city,Romania     

Ioana?Herbel  Adina-Eliza?CroitoruEmail author  Adina?Viorica?Rus  Cristina?Florina?Ro?ca  Gabriela?Victoria?Harpa  Antoniu-Flavius?Ciupertea  Ionu??Rus 《Theoretical and Applied Climatology》2018,133(3-4):681-695

The association between heat waves and the urban heat island effect can increase the impact on environment and society inducing biophysical hazards. Heat stress and their associated public health problems are among the most frequent. This paper explores the heat waves impact on surface urban heat island and on the local economy loss during three heat periods in Cluj-Napoca city in the summer of 2015. The heat wave events were identified based on daily maximum temperature, and they were divided into three classes considering the intensity threshold: moderate heat waves (daily maximum temperature exceeding the 90th percentile), severe heat waves (daily maximum temperature over the 95th percentile), and extremely severe heat waves (daily maximum temperature exceeding the 98th percentile). The minimum length of an event was of minimum three consecutive days. The surface urban heat island was detected based on land surface temperature derived from Landsat 8 thermal infrared data, while the economic impact was estimated based on data on work force structure and work productivity in Cluj-Napoca derived from the data released by Eurostat, National Bank of Romania, and National Institute of Statistics. The results indicate that the intensity and spatial extension of surface urban heat island could be governed by the magnitude of the heat wave event, but due to the low number of satellite images available, we should consider this information only as preliminary results. Thermal infrared remote sensing has proven to be a very efficient method to study surface urban heat island, due to the fact that the synoptic conditions associated with heat wave events usually favor cloud free image. The resolution of the OLI_TIRS sensor provided good results for a mid-extension city, but the low revisiting time is still a drawback. The potential economic loss was calculated for the working days during heat waves and the estimated loss reached more than 2.5 mil. EUR for each heat wave day at city scale, cumulating more than 38 mil. EUR for the three cases considered.  相似文献   

Impacts of river impoundment on dissolved heavy metals in floodplain soils of the Lahn River (Germany)     

Jens Hahn  Christian Opp  Nina Zitzer  Gabriela Laufenberg 《Environmental Earth Sciences》2016,75(15):1141

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Sedimentary facies,depositional processes and climatic controls in a Triassic Lake,Tanzhuang Formation,western Henan Province,China     

María Gabriela Mángano  Luis Alberto Buatois  Xiantao Wu  Junmin Sun  Guocheng Zhang 《Journal of Paleolimnology》1994,11(1):41-65

The Middle to Upper Triassic Tanzhuang Formation represents part of the infill of the early Mesozoic Jiyuan-Yima Basin. The upper part of this stratigraphic unit records deposition within prevailing shallow lake conditions. Well-developed sequences crop out near Jiyuan, western Henan Province, central China. Six sedimentary facies clustered into two facies assemblages were recognized in the lacustrine section. Facies assemblage 1 consists of stacked coarsening-upward sequences composed, from base to top, of organic-rich shales (facies E, type I), laminated siltstones (facies A) and current-rippled laminated sandstones (facies B). Units of assemblage 1 record progradation of small mouth-bar deltas within a perennial open lacustrine system under temperate and humid conditions. Facies assemblage 2 lacks a clear vertical pattern and consists of interbedded fine-grained carbonates and siltstones (facies C); deformed and wave-reworked sandstones (facies D); organic-rich shales (facies E, type II) and clayey mudstones (facies F). The assemblage also represents a perennial, hydrologically-open, shallow lacustrine system, but characterized by strong seasonal climatic control. Water stratification probably occurred in several periods of the lake history. Pangaean megamonsoonal influence is envisaged to explain the strong seasonality imprint evidenced toward the upper part of the Tanzhuang lacustrine column.This is the fourth paper in a series of papers published in this issue on Climatic and Tectonic Rhythms in Lake Deposits.  相似文献   

Landslide databases in the Geological Surveys of Europe     

Gerardo Herrera  Rosa María Mateos  Juan Carlos García-Davalillo  Gilles Grandjean  Eleftheria Poyiadji  Raluca Maftei  Tatiana-Constantina Filipciuc  Mateja Jemec Auflič  Jernej Jež  Laszlo Podolszki  Alessandro Trigila  Carla Iadanza  Hugo Raetzo  Arben Kociu  Maria Przyłucka  Marcin Kułak  Michael Sheehy  Xavier M. Pellicer  Charise McKeown  Graham Ryan  Veronika Kopačková  Michaela Frei  Dirk Kuhn  Reginald L. Hermanns  Niki Koulermou  Colby A. Smith  Mats Engdahl  Pere Buxó  Marta Gonzalez  Claire Dashwood  Helen Reeves  Francesca Cigna  Pavel Liščák  Peter Pauditš  Vidas Mikulėnas  Vedad Demir  Margus Raha  Lídia Quental  Cvjetko Sandić  Balazs Fusi  Odd Are Jensen 《Landslides》2018,15(2):359-379

Landslides are one of the most widespread geohazards in Europe, producing significant social and economic impacts. Rapid population growth in urban areas throughout many countries in Europe and extreme climatic scenarios can considerably increase landslide risk in the near future. Variability exists between European countries in both the statutory treatment of landslide risk and the use of official assessment guidelines. This suggests that a European Landslides Directive that provides a common legal framework for dealing with landslides is necessary. With this long-term goal in mind, this work analyzes the landslide databases from the Geological Surveys of Europe focusing on their interoperability and completeness. The same landslide classification could be used for the 849,543 landslide records from the Geological Surveys, from which 36% are slides, 10% are falls, 20% are flows, 11% are complex slides, and 24% either remain unclassified or correspond to another typology. Most of them are mapped with the same symbol at a scale of 1:25,000 or greater, providing the necessary information to elaborate European-scale susceptibility maps for each landslide type. A landslide density map was produced for the available records from the Geological Surveys (LANDEN map) showing, for the first time, 210,544 km² landslide-prone areas and 23,681 administrative areas where the Geological Surveys from Europe have recorded landslides. The comparison of this map with the European landslide susceptibility map (ELSUS 1000 v1) is successful for most of the territory (69.7%) showing certain variability between countries. This comparison also permitted the identification of 0.98 Mkm² (28.9%) of landslide-susceptible areas without records from the Geological Surveys, which have been used to evaluate the landslide database completeness. The estimated completeness of the landslide databases (LDBs) from the Geological Surveys is 17%, varying between 1 and 55%. This variability is due to the different landslide strategies adopted by each country. In some of them, landslide mapping is systematic; others only record damaging landslides, whereas in others, landslide maps are only available for certain regions or local areas. Moreover, in most of the countries, LDBs from the Geological Surveys co-exist with others owned by a variety of public institutions producing LDBs at variable scales and formats. Hence, a greater coordination effort should be made by all the institutions working in landslide mapping to increase data integration and harmonization.  相似文献   

Fluid–Rock Interactions in Geothermal Reservoirs,Germany: Thermal Autoclave Experiments Using Sandstones and Natural Hydrothermal Brines     

Schäffer  Rafael  Götz  Emilia  Schlatter  Nils  Schubert  Gabriela  Weinert  Sebastian  Schmidt  Stefanie  Kolb  Ute  Sass  Ingo 《Aquatic Geochemistry》2022,28(2):63-110

As renewable energy, geothermal can contribute substantially to the energy transition. To generate electricity or to harvest heat, high-saline fluids are tapped by wells of a few kilometres and extracted from hydrothermal reservoirs. After the heat exchanger units have been passed by, these fluids are reinjected into the reservoir. Due to the pressure and temperature differences between the subsurface and the surface, as well as the cooling of the fluids in the power plant, unwanted chemical reactions can occur within the reservoir, in the borehole, and within the power plant itself. This can reduce the permeability of the reservoir as well as the output of the geothermal power plant. This study aims to simulate real subsurface reactions using batch and leaching experiments with sandstone or sandstone powder as solid phase, and deionised water or natural brine as liquid phase. It is demonstrated that fluid composition changes after only a few days. In particular, calcite, aragonite, clay minerals, and zinc phases precipitate from the natural brine. In contrast, in particular minerals containing potassium, arsenic, barium, and silica are dissolved. Due to the experimental set-up, these mineral reactions mainly took place on the surface of the samples, which is why no substantial changes in petrophysical properties could be observed. However, it is assumed that the observed reactions on the reservoir scale have a relevant influence on parameters such as permeability.

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Hydrogeochemical and nitrate isotopic evolution of a semiarid mountainous basin aquifer of glacial-fluvial and paleolacustrine origin (Lake Titicaca,Bolivia): the effects of natural processes and anthropogenic activities     

Flores Avil&#;s  Gabriela Patricia  Spadini  Lorenzo  Sacchi  Elisa  Rossier  Yvan  Savarino  Joel  Ramos  Oswaldo Eduardo  Duwig  C&#;line 《Hydrogeology Journal》2022,30(1):181-201

Hydrogeology Journal - A hydrogeochemical and stable isotopic ( $${\updelta }^{15}{\mathrm{N}}_{{\mathrm{NO}}_{3}}$$ and $${\updelta }^{18}{\mathrm{O}}_{{\mathrm{NO}}_{3}}$$ ) multitracer approach...  相似文献   

Analytic hierarchy process applied to landslide susceptibility mapping of the North Branch of Argentino Lake,Argentina     

Moragues  Silvana  Lenzano  María Gabriela  Lanfri  Mario  Moreiras  Stella  Lannutti  Esteban  Lenzano  Luis 《Natural Hazards》2021,105(1):915-941

Natural Hazards - In the present study, we achieved the susceptibility mapping to slope instability processes by the implementation of Analytic Hierarchy Process and Weighted Linear Combination...  相似文献   

Accelerating the solution of linear systems appearing in two-phase reservoir simulation by the use of POD-based deflation methods     

Diaz Cortés  Gabriela Berenice  Vuik  Cornelis  Jansen  Jan-Dirk 《Computational Geosciences》2021,25(5):1621-1645

We explore and develop a Proper Orthogonal Decomposition (POD)-based deflation method for the solution of ill-conditioned linear systems, appearing in simulations of two-phase flow through highly heterogeneous porous media. We accelerate the convergence of a Preconditioned Conjugate Gradient (PCG) method achieving speed-ups of factors up to five. The up-front extra computational cost of the proposed method depends on the number of deflation vectors. The POD-based deflation method is tested for a particular problem and linear solver; nevertheless, it can be applied to various transient problems, and combined with multiple solvers, e.g., Krylov subspace and multigrid methods.

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