ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Artikel  (96)
  • Neueste Artikel (Zeitschrifteninhaltsverzeichnisse / in press)  (53)
  • Artikel: DFG Deutsche Nationallizenzen  (43)
  • American Geophysical Union  (36)
  • International Union of Crystallography (IUCr)  (30)
  • Blackwell Publishing Ltd  (13)
  • Oxford University Press  (11)
  • Arctic Institute of North America  (4)
  • Society for Sedimentary Geology
  • 1990-1994  (71)
  • 1985-1989  (23)
  • 1980-1984
  • 1975-1979
  • 1950-1954  (2)
  • 1991  (28)
  • 1990  (43)
  • 1989  (23)
  • 1952  (1)
  • 1950  (1)
  • Geologie und Paläontologie  (90)
  • Geographie  (5)
  • Mathematik  (5)
Sammlung
  • Artikel  (96)
Datenquelle
  • Neueste Artikel (Zeitschrifteninhaltsverzeichnisse / in press)  (53)
  • Artikel: DFG Deutsche Nationallizenzen  (43)
Verlag/Herausgeber
Erscheinungszeitraum
  • 1990-1994  (71)
  • 1985-1989  (23)
  • 1980-1984
  • 1975-1979
  • 1950-1954  (2)
Jahr
Zeitschrift
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 37 (1989), S. 0 
    ISSN: 1365-2478
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Physik
    Notizen: Ground-penetrating radar is a technique which offers a new way of viewing shallow soil and rock conditions. The need to better understanding overburden conditions for activities such as geochemical sampling, geotechnical investigations, and placer exploration, as well as the factors controlling groundwater flow, has generated an increasing demand for techniques which can image the subsurface with higher resolution than previously possible.The areas of application for ground-penetrating radar are diverse. The method has been used successfully to map ice thickness, water depth in lakes, bedrock depth, soil stratigraphy, and water table depth. It is also used to delineate rock fabric, detect voids and identify karst features. The effective application of the radar for the high-resolution definition of soil stratigraphy and fractures in bedrock is highlighted.The basic principles and practices involved in acquiring high quality radar data in the field are illustrated by selected case histories. One example demonstrates how radar has been used to map the bedrock and delineate soil horizons to a depth of more than 20 m. Two case histories show how radar has been used to map fractures and changes of rock type to 40 m range from inside a mine. Another case history demonstrates how radar has also been used to detect and map the extent of groundwater contamination. The corroboration of the radar results by borehole investigations demonstrates the power and utility of the high-resolution radar method as an aid for interpolation and extrapolation of the information obtained with conventional coring programmes. With the advent of new instrumentation and field procedures, the routine application of the radar method is becoming economically viable and the method will see expanded use in the future.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 27 (1989), S. 0 
    ISSN: 1745-6584
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik , Geologie und Paläontologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 28 (1990), S. 0 
    ISSN: 1745-6584
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik , Geologie und Paläontologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 29 (1991), S. 0 
    ISSN: 1745-6584
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik , Geologie und Paläontologie
    Notizen: This paper examines hydrogeologie effects of proposed diversion of water from the Mediterranean Sea to the Qattara Depression for generation of electricity in northwestern Egypt. The Lower Miocene Moghra aquifer directly underlies the Qattara Depression, extending to the east and dipping beneath younger formations to the north. The Qattara Depression is a sink for ground-water flow from the Nile Delta aquifer in the east, the Mediterranean Sea in the north, and the Nubian artesian aquifer in the south. In this study, a two-dimensional finite-difference model was used in conjunction with available meteorologie, geologic, and hydrologie data to characterize the present ground-water conditions in this aquifer and to make predictions about the water-table rise which could occur as a result of the proposed Qattara Reservoir. Model predictions indicate that creation of the reservoir could cause a 30-meter rise of the Moghra aquifer's water table in the central part of the Qattara Depression. This water-table rise decreases to the north and east. Transient simulations indicate that steady-state conditions in the modeled area of the Moghra aquifer are not likely to be reached during the expected 100-year lifetime of the reservoir.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 28 (1990), S. 0 
    ISSN: 1745-6584
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Energietechnik , Geologie und Paläontologie
    Notizen: Ground water in the immediate vicinity of an area previously used for the disposal of charcoal manufacturing wastes has been shown to contain low levels of phenolic and polycyclic compounds. Based on the analysis of samples obtained from monitoring wells, the levels of the organic contaminants are reduced to near or below the detection limit within a distance of 100 meters downgradient of the fill. Examination of the ground-water chemistry indicated that the aquifer is essentially aerobic across the site, except in the immediate vicinity of the fill. At this point, dissolved oxygen is apparently depleted due to the biodegradation of organic contaminants introduced into the ground water, with a concomitant increase in the inorganic carbon concentration. Laboratory microcosm experiments demonstrated that the naturally occurring microorganisms can readily degrade a mixture of the predominant organic contaminants. Half-lives for biodegradation were in the range of 3 to 8 days for phenolic substrates, and 11 to 18 days for naphthalene. Computer model simulations indicated that the attenuation observed in the aquifer cannot be explained in terms of physical processes such as adsorption or dispersion, but is consistent with biological degradation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 102 (1990), S. 0 
    ISSN: 1365-246X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: Multipenetration heat flow measurements have been made at four sites in deep basins of the west-central Pacific Ocean: the West Mariana Basin, Central Mariana Basin, Nauru Basin and Central Pacific Basin. The final heat flows are, respectively, 46.6 /pm 0.5, 49.4 /pm 0.2, 44.2 /pm 0.9 and 49.5 /pm 1.1 mW m-2. Each site was surveyed by single-channel seismic reflection profiling, and provided a gravity core. The instrument measured thermal conductivity in situ over the entire depth intervals used for determination of the gradients, and the reduction scheme iterated conductivity and heat-capacity changes into the fitting procedure, both of entry frictional decays and of conductivity heat pulse decays. The absolute accuracy of the instrument should approach 2 per cent and the first site would make a good intercalibration standard for heat flow measurement. The heat flow variation between the sites is real, and there is also a significant variation in the isostatically reduced depths of the sites. There is no age progression of either depth or heat flow, and, when five other good multidata points are included, the relationship between depth and heat flow conforms to that expected from simple cooling models only in an average sense for the whole group. The most plausible explanation for the variations is that heat flow and thermal elevation are dependent on different levels of deep lithosphere reheating at different times between 70 and 120 Myr ago. It is suggested that additional topographic variation is caused by the different accumulations of sediment and lava flows at each site, and to errors in the isostatically reduced depths due to incomplete knowledge of the stratigraphy down to the crust-mantle interface. These explanations of the topographic variation could be tested by seismic refraction measurements.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 102 (1990), S. 0 
    ISSN: 1365-246X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: Examples of Gräfenberg-array data showing anomalous P-waves which typically arrive 3–5 s after the direct P-wave and which have a slowness 0.7–0,8 s deg-1 smaller than direct P are presented. This additional phase is most frequently observed for events located in the NE portion of the southern Kurile Island subduction zone 73°-80° from Gräfenberg, but systematically disappears for events in the SW portion of this zone.Because of the magnitude of the slowness difference, these observations cannot be attributed to a complex source rupture process nor to multipathing through the descending slab. Likewise, they may not be accounted for by near-receiver structure because these phases are not seen for all Kurile events. If present they appear at all stations of the array but they follow direct P too closely to be a multiple from the Mono. Therefore, we conclude they are very likely caused by lower mantle velocity structure.The most likely explanation is the presence of a P velocity jump of about 3 per cent approximately 290km above the core-mantle boundary, since such a reflector in the lowermost mantle not only gives a good fit of traveltimes and slowness but is also able to model the waveform and the amplitudes of this additional P phase. the distribution of bounce points on this reflector for the Kurile events indicates a lateral extension of this velocity anomaly under northern Siberia of about 150 km by at least 200 km. the best fitting S-wave model has a reflector in the same depth, but the velocity contrast seems to be only about 2 per cent suggesting a different behaviour of the P and S velocity in D″.Few events from other regions in this distance range are suitable for a definitive analysis of this kind. From among this group some observations indicate a lower mantle anomaly under the Lomonosow Ridge and under northern Greenland; but since the lower mantle under western Siberia, northern Novaya Zemlya, the Azores Islands region and the USSR-Afghanistan border region does not produce an additional phase in the Gräfenberg recordings it is very unlikely that such a velocity anomaly in the lowermost mantle is a global feature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 106 (1991), S. 0 
    ISSN: 1365-246X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: We derive the elastostatic field arising from the introduction of a 2-D dipping antiplane crack at the surface of an elastic half-space having a pre-existing uniform field. The problem is equivalent to that of two identical, joined, antiplane cracks in an infinite, uniformly strained medium; each crack is inclined by the same amount from the axis of symmetry, giving rise to a bent crack. For cracks with the same depth of crack tip beneath the surface, the amount of elastic energy released increases with the angle from the vertical. However, the rate of energy release with increasing angle is less than the rate of increase of surface energy. Plane, vertical cracks are favoured energetically in infinite, homogeneous media, while bent cracks are favoured in heterogeneous media where a crack must deviate from straight line growth in order to bypass a high-strength barrier. We compare the trade-offs in total energy of bent cracks with barrier energies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 104 (1991), S. 0 
    ISSN: 1365-246X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: This paper investigates several aspects of synthetic catalogue generation and aftershock identification schemes. First, we introduce a method for generating synthetic catalogues of earthquakes. This method produces a catalogue which has the geographic appearance of an actual catalogue when the hypocentres are plotted in map view, but allows us to vary the spatial and temporal relationships between pairs of close events. Second, we discuss six statistics to measure certain characteristics of synthetic and actual catalogues. These include four new statistics So, Bo, S1 and B1 which evaluate the distributions of link lengths between events in space and space-time as computed by single-link cluster analysis (SLC). Third, we develop a new scheme for identifying aftershocks in which a group of events forms an aftershock sequence if each event is within a space-time distance D of at least one other event in the group. We define the space-time separation of events by dst=√(d2+C2τ2), where d is the spatial separation of events, τ is the time separation, and C= 1km day-1. Our experience with several synthetic catalogues suggests that an appropriate trial value for D is 9.4 km1/2 (√S1) - 25.2 km. Here, S1, is the median link length using SLC with the metric dsT. Fourth, we generate synthetic catalogues resembling both teleseismic and local network catalogues to evaluate the validity and reliability of this aftershock identification scheme, as well as other schemes proposed by Gardner & Knopoff (1974), Shlien & Toksöz (1974), Knopoff, Kagan & Knopoff (1982), and Reasenberg (1985). Using a simple scoring method, we find that the SLC method compares favourably with other aftershock identification algorithms described in the literature.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical journal international 99 (1989), S. 0 
    ISSN: 1365-246X
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie
    Notizen: Observations of underside P-wave reflections from discontinuities deep within the upper mantle which precede the P'P’ phase have provided important constraints on the existence and physical properties of these dynamically critical features. In this study, we extend earlier work by examining for the first time, broad-band recordings of those earthquakes for which one would expect to observe P'P’ and its associated precursors P'dP’. An exhaustive search of 20 yr of Carnegie data and 11 yr of Gräfenberg data uncovered a number of fine P‘P’ observations, but in only one or perhaps two instances are there evidence of a precursor from near 670 km depth. These null results are consistent with what has been reported in earlier studies and provide us with an opportunity to estimate the variability of P velocity near 670 km or, alternatively, the scale length of discontinuity topography which acts to defocus the precursor. This has been done by using the reflectivity and Gaussian beam methods to compute synthetic seismograms for a suite of 1-D and 2-D earth models which vary slightly from PREM. We find that the null data may be satisfied either by (i) reducing the PREM impedance jump at 670 km from 8.5 to 4-5 per cent; (ii) smoothing this 8.5 per cent jump linearly over a zone 15-30 km thick or (iii) imposing deformations in the 670 km discontinuity as small as 10 km in amplitude and 300 km in wavelength. For the one case of an observed precursor, the relative size of the underside reflection and main P‘P’ phase suggests that, in this instance, the precursor's amplitude is correctly predicted by PREM.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...