Within the scope of the International Decade ofNatural Disaster Reduction (IDNDR), cause-effectmodels of large landslides are being developed toestimate hazard. This work is based on a structuralexploration of the landslide areas mainly by seismicmethods. Information about the status of deformationis obtained by comparison of the actual topographywith a reconstruction of the original topography, byGPS, and by SAR interferometry. Geologic andgeomorphological evidence, as well as relevantinformation from other geo-scientific disciplines, isconsidered. The Finite Element Method is used to modelthe initial phase of a mass movement. Later on thismodeling will be extended to the quasi-stationarycreep phase and the transition from creeping to rapidsliding.Four large landslides within the crystalline rocks ofthe Eastern Alps have been investigated since 1997.Two of them are evaluated so far, and are presented inthis paper. The largest one is the Köfelslandslide with a total volume of 3.9 km3 and apotential energy release of 5 × 1016 Joule.Refraction and reflection multi-component seismictechniques were used to resolve structure and elasticparameters of the landslide masses. For the modelingof the initial phase of the landslides by the FiniteElement Method a strain softening behavior of the rockmass has been assumed. The development of softened orfractured zones was successfully simulated, inagreement with the structures obtained by the seismicmeasurements. 相似文献
The need for storage caverns for oil and gas, and repositories for toxic chemical waste is increasing world-wide. Rock salt formations are particularly suitable for the construction of cavities for such purposes. Owing to its favourable geomechanical properties, rock salt remains stable over long periods of time without support, and it can be shown that the geological barrier of the host rock remains intact for a remarkably long time.
Safety analysis must be made for each proposed site based on site-specific data. The methods of doing this are well known and related technical recommendations exist in Germany. These recommendations apply to the planning, construction, operation and post-operational management of salt caverns used for the underground disposal of hazardous wastes. In particular, geotechnical site-specific safety verification, as required by the government's technical regulations on wastes (TA-Abfall) under the section “Underground Disposal”, is required. This safety verification must cover the entire system comprising the waste, the cavern and the surrounding rocks. For this purpose geomechanical models have to be developed. The steps which must be taken when carrying out geological engineering site explorations and when determining geotechnical parameters are discussed. In addition, recommendations are made for the design and construction of underground repositories.
For liquid-filled caverns, long-term sealing from the biosphere is of particular interest. In this instance it must be shown that the natural increase in pressure in the closed cavity due to long-term convergence does not exceed the fracture pressure. A special filled test (scale 1:1) has been performed to study this. 相似文献
Cross-line recording formed a companion experiment of the TRANSALP seismic reflection transect through the Eastern Alps, conducted by partner institutions from Austria, Germany and Italy in three field campaigns in the period fall 1998 to fall 1999. Besides of the originally expected three-dimensional control for the north–south running main transect, additional information on seismic anisotropy and alternative images of crucial parts of the main transect could be gained.Conventionally processed sections along N–S running common-midpoint (CMP) binning lines confirm and strengthen the predominance of midcrustal reflective structures of the ‘Sub-Tauern-Ramp’ beneath and south of the Tauern Window. Velocity analysis of the first arrivals exhibit about 10% higher velocities in east–west propagating P-waves, compatible with texture-dominated rock anisotropy, recorded on cross-lines at the Tauern Window. Pre-stack depth migration of cross-line recordings shows dominant south dip of the Sub-Tauern-Ramp with easterly dip components and a sub-horizontal root zone of the Sub-Dolomites-Ramp. 相似文献
Global carbon stocks in forest biomass are decreasing by 1.1 Gt of carbon annually, owing to continued deforestation and forest
degradation. Deforestation emissions are partly offset by forest expansion and increases in growing stock primarily in the
extra-tropical north. Innovative financial mechanisms would be required to help reducing deforestation. Using a spatially
explicit integrated biophysical and socio-economic land use model we estimated the impact of carbon price incentive schemes
and payment modalities on deforestation. One payment modality is adding costs for carbon emission, the other is to pay incentives
for keeping the forest carbon stock intact. 相似文献
During the eighties, microgravity research focussed predominantly on the investigation of fundamental phenomena, often with
limited industrial support. Although this approach led to some rather impressive breakthroughs in terms of new theoretical
insights and microgravity experimentation, the need for increased co-ordination and interest from industry became increasingly
apparent. In this decade, a user-driven research strategy has been instigated by ESA to promote microgravity research. The objective is to coordinate ESA, national
activities and industry into an overall European strategy, which will allow valuable application-oriented microgravity research
to be performed aboard the International Space Station (ISS). On this basis, it is expected that scientific progress will
evolve even more rapidly due to the easier planning, regular access and longer experiment-durations associated with the ISS.
This paper highlights the wealth of microgravity research being co-ordinated by ESA in the field of physical sciences. A number of key areas of research under microgravity conditions are currently being explored such as alloy solidification,
crystal growth,measurement of thermophysical properties, combustion mechanisms, fluid flow, cold atom physics and complex
plasmas, to name but a few. The following sections will provide background information relating to the various ESA research
programmes, as well as emphasising their microgravity relevance.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
The influence of pressure on the OH-stretching vibration of zoiste has been studied by single crystal high pressure infrared spectroscopy. A band related to the OH-stretching vibration displayed a linear shift from 3170 cm?1 at 1 bar to 2795 cm?1 at 116 kbar. The half-band width increased linearly with respect to pressure from 60 cm?1 at 1 bar to 500 cm?1 at 116 kbar. The strength of the absorption of this band is strongly frequency dependent. The high-energy shift of a band at around 2200 cm?1 on pressure increase indicates that this band is not due to a second OH-stretching vibration as previously suggested by Langer and Lattard (1980). 相似文献
The eclipse mosaic (PIA08329) of the Saturn system, taken on September 15, 2006 when Cassini was in Saturn’s shadow, contains numerous color images of the Enceladus plume and the E ring at phase angles ranging from 173° to 179°. These forward-scattering observations sample the diffraction peak for particle radii in the 1–5 μm range. The phase angle dependence and total brightness are sensitive indicators of the total mass of solid material in the plume. We fit the data with a variety of particle shapes and size distributions, and find that the median radius of the equivalent-volume sphere is 3.1 μm, with an uncertainty of ±0.5 μm. The total mass of particles in the plume is (1.45 ± 0.5) × 105 kg. We have not considered variations with altitude in the particle size and shape distribution, and we leave that for another paper. We find that the brightness of the E ring varies with position in the orbit, not only because of the viewing geometry, e.g., variations in phase angle, but also because of some unknown intrinsic variability. The total mass of solid material in the E ring is (12 ± 5.5) × 108 kg. For the plume, the production rate of particles – the mass per unit time leaving the vents is 51 ± 18 kg s−1. We estimate that 9% of these particles are escaping from Enceladus, implying lifetimes of ∼8 years for the E ring particles. Based on three comparisons with vapor amounts from ultraviolet spectroscopy, the ice/vapor ratio is in the range 0.35–0.70. This high ratio poses a problem for theories in which particles form by condensation from the gas phase, and could indicate that particles are formed as spray from a liquid reservoir. 相似文献