In-Situ Electrical Conductivity and Permeability of Mid-Crustal Rocks from the Ktb Drilling: Consequences for High Conductive Layers in the Earth Crust   总被引：2，自引：0，他引：2  

G. Nover  S. Heikamp  H.J. Meurer  D. Freund 《Surveys in Geophysics》1998,19(1):73-85

Freshly cored samples from a microprofile (7011–7013m in depth) of the German Continental Deep Drilling Project (KTB) were taken to measure the complex electrical conductivity (1 kHz up to 1 MHz), porosity, BET-surface, permeability and density. The porosity ranged about 1 vol%, while the permeability k varied from 16.05 µD to > 0.01 µD for in-situ pressure conditions. The permeability decreased about 2 orders in magnitude up to pressures of 200 MPa. Conductivity was measured in the same pressure range on 1 M NaCl saturated samples. Thin sections and SEM analysis revealed an enrichment of carbon and ilmenite (about 1 vol%) on inner cleavage cracks of mica, thus causing an unusual high (ranging from 4.2 × 10^-3 S/m to 67 × 10^-3 S/m) being orders of magnitude higher than normally measured on such types of rocks (about 300 × 10^-6 S/m). An inverse pressure dependence of was detected on some of the samples. Electronic conduction was confirmed by least-squares-fits of model data to the frequency dispersion of the conductivity and by measuring the time dependence of the volume conductivity and its frequency dispersion. Thus the dominating role of the reconnected network of carbon and ilmenite on the enhanced volume conductivity was proved. An increase of the conductivity due to hydrofracturing by high pore fluid pressures plays a less important role.  相似文献   

Can silicon monoxide grains be responsible for the interstellar 9.7 micrometer absorption band?     

J. Gürtler  Regina Schmidt  J. Dorschner  C. Friedemann 《Astrophysics and Space Science》1981,80(1):249-255

In this paper results of an experimental investigation of the spectra of submicrometersized silicon monoxide grains are presented. The grains manufactured from commercial SiO were prepared according to the Jena IR spectroscopy program for particulates of cosmic importance. The comparison of the laboratory spectra with those derived by means of Mie calculations using published refractive indices of bulk SiO revealed a fundamental discrepancy concerning the number and the positions of the bands. Therefore, the experimental SiO grains are suggested to change their internal structural state by the heating connected with the pressing of the KBr pellets, where the grains are embedded in. This sensitivity against heating by some hundred K rules out that SiO grains can be responsible for the 9.7 m circumstellar as well as interstellar spectral feature.  相似文献   

A semi-probabilistic procedure for developing societal risk function     

Hing-Ho Tsang  James E. Daniell  Friedemann Wenzel  Amelie C. Werner 《Natural Hazards》2018,90(2):943-974

Among the coastal districts of mega city Istanbul, Bakirkoy is one of the most critical one with the importance of air and marine transportation and presence of many other coastal facilities and structures that are prone to suffer from marine hazards. In the history, the Sea of Marmara has experienced numerous earthquake and landslide events and associated tsunamis. Therefore, tsunami risk assessment is essential for all coastal districts of Istanbul, including Bakirkoy district. In this study, a further developed methodology for tsunami human vulnerability and risk assessment Metropolitan Tsunami Human Vulnerability Assessment (MeTHuVA) is applied for Bakirkoy district of Istanbul, considering earthquake generated tsunamis. High-resolution tsunami hazard analysis is performed with the integration of coastal inundation computation with tsunami numerical tool NAMI DANCE and tsunami human vulnerability assessment with GIS-based multi-criteria decision analysis methods (MCDA). Using analytical hierarchy process method of MCDA, a hierarchical structure is established, composed of two main elements of tsunami human vulnerability: Vulnerability at Location and Evacuation Resilience. Tsunami risk assessment for Bakirkoy district is calculated by integrating result of hazard and vulnerability assessments with a risk relation that includes a parameter (n), which represents the preparedness and awareness level of the community. Tsunami simulations revealed that the maximum inundation distance is over 350 m on land and water penetrates almost 1700 m along Ayamama stream. Inundation is observed in eleven neighborhoods of Bakirkoy district. In the inundation zone, maximum flow depth is found to be over 5.7 m. The inundated area forms 4.2% of whole Bakirkoy district, and 62 buildings are located in the inundation zone. Hazard, vulnerability and risk assessment results for different neighborhoods of Bakirkoy district are presented and discussed.  相似文献   

Fluctuations of electrical conductivity as a natural tracer for bank filtration in a losing stream     

Tobias Vogt  Eduard Hoehn  Philipp Schneider  Anja Freund  Mario Schirmer  Olaf A. Cirpka 《Advances in water resources》2010

A key parameter used in the assessment of bank filtration is the travel time of the infiltrated river water during the passage through groundwater. We analyze time series of electrical conductivity (EC) in the river and adjacent groundwater observation wells to investigate travel times of young hyporheic groundwater in adjoining channelized and restored sections of River Thur in North-East Switzerland. To quantify mixing ratios and mean residence times we perform cross-correlation analysis and non-parametric deconvolution of the EC time series. Measurements of radon-222 in the groundwater samples validate the calculated residence times. A simple relationship between travel time and distance to the river has not been observed. Therefore, we speculate that the lateral position and depth of the thalweg as well as the type of bank stabilization might control the infiltration processes in losing rivers. Diurnal oscillations of EC observed in the river and in nearby observation wells facilitate analyzing the temporal variation of infiltration. The diurnal oscillations are particularly pronounced in low flow situations, while the overall EC signal is dominated by individual high-flow events. Differences in travel times derived from diurnal and overall EC signals thus reflect different infiltration regimes.  相似文献   

The interstellar 217 nm band: a third catalogue of equivalent widths     

C. Friedemann  U.-K. Rder 《Astronomische Nachrichten》1987,308(1):41-61

Using the data obtained with the ultraviolet photometer in the Astronomical Netherlands Satellite the equivalent widths of the interstellar 217 nm band as well as other parameters characterizing the behaviour of the continuous interstellar extinction in the wavelength region of the band have been derived for 790 O, B stars with colour excesses E(B - V) ≥ 0·4 mag.  相似文献   

Basin modeling meets rift analysis – A numerical modeling study from the Jeanne d'Arc basin,offshore Newfoundland,Canada     

Friedemann Baur  Ralf Littke  Hans Wielens  Carolyn Lampe  Thomas Fuchs 《Marine and Petroleum Geology》2010

The Jeanne d'Arc basin, on the Grand Banks offshore Newfoundland, is a confined, failed-rift basin. Its initial development and burial history were controlled by crustal stretching and thinning. This study provides a detailed analysis of the heat flow-, tectonic subsidence-, stretching factor-, maturation- and temperature history, based on 44 1D models- and one full 4D (space and time) model.  相似文献   

A Catalogue of Extremely Young,Massive and Compact Infrared Objects (Mitteilungen der Universitäts-Sternwarte zu Jena Nr. 165)     

Th. Henning  C. Friedemann  J. Gürtler  J. Dorschner 《Astronomische Nachrichten》1984,305(2):67-78

Starting from the Becklin-Neugebauer Object in Orion as a prototype, a class of compact infrared sources thought to be young massive stars surrounded by optically thick dust shells is identified by means of a wide range of their observable features. A catalogue of 34 such objects is compiled, providing comprehensive information such as infrared and radio spectra, maser sources, and outflow phenomena.  相似文献   

Discussion of "A Comparison of Ground Water Monitoring Data from CERCLA and RCRA Sites," by Russell H. Plumb, Ground Water Monitoring Review, pg. 94, Fall 1987.     

Jerry R. Garman  Vernon B. Myers  chief  Thomas Freund  chemist 《Ground Water Monitoring & Remediation》1988,8(3):166-167

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A search for extremely red stars on the palomar observatory sky survey. II. Examination for light variability     

C. Friedemann  J. Gürtler  W. Pfau 《Astronomische Nachrichten》1977,298(6):327-329

The extremely red stars discovered on some Palomar Sky Survey prints in an earlier paper were investigated for variability. Four certain and one probable variables were found.  相似文献   

Carbon in olivine single crystals analyzed by the ¹²C(d,p)¹³C method and by photoelectron spectroscopy     

Gert Oberheuser  Hendrik Kathrein  Guy Demortier  Horst Gonska  Friedemann Freund 《Geochimica et cosmochimica acta》1983,47(6):1117-1129

Carbon subsurface concentration profiles in olivine single crystals from San Carlos, Arizona, and the Sergebet Island. Red Sea, containing total carbon between 60–180 wt.-ppm, were analyzed by means of the ¹²C(d. p)¹³C nuclear reaction and by x-ray induced photoelectron spectroscopy (XPS) in combination with acid etching and with Ar⁺ ion sputtering respectively, between 200–930 K. The (d, p) analysis reveals equilibrium subsurface C profiles extending 1–2 μm or more into the bulk. Their steepness is a function of temperature. Typical mean C concentrations at 300 K in the resolvable layers, 0–0.6, 0.6–1.2, and 1.2–1.8 μm. are 1.8, and 0.6 wt.-%, corresponding to enrichment factors over the mean bulk C concentration of the order of 100, 40 and 30 respectively. In the topmost atomic layers analyzed by XPS the carbon is enriched by a factor of the order of 1000, decreasing with increasing temperature. The results suggest that the carbon is in a truly dissolved state and highly mobile, subject to a reversible subsurface segregation. Most probably local lattice strain associated with the solute C species provide the driving force for this diffusional process. The C diffusion coefficient was determined from the (d, p) data below 300 K: D= 10^?13 exp(?7.8/RT) [m²· sec^?1; KJ · mole^?1] and from XPS data between 450–925 K: D = 10^?14 exp(-6/RT) [m² · sec^?1; KJ · mole^?1] The estimated error of the preexponential factors is ± one order of magnitude, that of the activation energies ±3.5 and ±2 KJ mole^?1 respectively.  相似文献