ALBERT

Beschreibung: Three-component wide-angle seismic data acquired in southern Tibet during Project INDEPTH show strong P-to-S converted reflections from reflectors that are aligned at a depth of ∼15 kilometers beneath the northern Yadong-Gulu rift. These converted reflections are locally higher in amplitude than the corresponding P-wave reflections. Modeling of reflection mode conversion as a function of incidence angle indicates that this condition obtains for a reflector that is a solid over fluid interface; it is not typical of a solid-solid interface. The likely candidates for a fluid trapped within the crystalline crust of southern Tibet are granitic magma and water (brine).

Beschreibung: In sequence of the GFZ93 high resolution gravity models (Gruber Th., et al, 1993) a new model, named GFZ95A, which is complete to degree and order 360 of a spherical harmonic series was computed. The model is based on new data sets, which were collected during the last months. This new data promises a major step towards a more precise high resolution gravity model. Especially from new available data over CIS (Community of Independent States) major progress can be expected with respect to the former models, which were based on predicted data in this area.

Beschreibung: Fast polarization directions α of split SKS waves in Central Europe change from NE/ENE in the western part to dominatingly E/ESE orientation towards north and east. This coincides strikingly well with the dominating trend of Hercynian deformational crustal features. It hints to frozen anisotropy related to paleo-crustal fabric. But when considering plausible anisotropy values of about 2–3% then only a small fraction (δt 〈 0.3 s) of the rather large observed average delay-times (δt = 0.83 ± 0.31 s) between the two split waves could be attributed to structural anisotropy in the relatively thin Central European crust. Therefore, the main “anisotropy signal” has to be associated with lattice-preferred orientation (LPO) of olivine below the crust. It may be either frozen in the subcrustal lithosphere since Hercynian times or have developed more recently in the asthenosphere. The thickness of the lithosphere varies significantly beneath Europe and the depth contours show systematic changes in trend. The latter varies from dominatingly NE in the southwest to SE in the north and east. The polarization directions α of the fast split SKS waves observed at seismic stations in proximity to the southern and northeastern boundaries of Central Europe are subparallel to the trends of these strong anomalies in lithosphere topography. A causal relationship is assumed and a new model proposed to explain the observations in α and δt. It takes into account the possible effects of paleo-deformational events. They may have produced both anisotropic crustal fabric and probably still preserved and similarly trending frozen LPO in the subcrustal lithosphere. The model also considers the influence of recent absolute motion of the West European lithospheric plate towards NE and the effect of its pronounced lower boundary topography on the formation and trend of LPO in the asthenosphere. Accordingly, the effects of anisotropy of different nature and age at different depth levels but with similar trend may superimpose constructively. This could explain the rather large delay-times observed at Central European stations which are too large to be attributed to frozen anisotropy in the lithosphere alone. The model would even permit the total effect observed to be attributed to asthenosphere flow controlled by absolute plate motion direction and lithosphere-asthenosphere boundary topography.

Beschreibung: Evaluation of numerous data from different methods of measurement and theories applied in high-pressure physics shows that the strain energy of a monophase system, which represents the low- or a high-pressure phase of a hydrostatically compressed substance mostly relevant to planetary physics, approximates to a term proportional to the square of an auxiliary function of the volumetric contraction, the bulk modulus and its successive partial derivatives with respect to pressure at the initial state of the thermodynamical system. From this it follows that new-defined polynomial equations in the initial values of the bulk modulus and its pressure derivatives must be satisfied, which is checked for many elements, halides, oxides, minerals, and rocks. Using a suitably chosen auxiliary function, the strain energy, pressure, bulk modulus and its first pressure derivative at any equilibrium state of the monophase system are represented by approximation functions of the volumetric contraction as well as the initial values of the bulk modulus and its derivatives. The information content of these functional relations called Model N if they include derivatives of the bulk modulus only up to the order N surpasses, already in the cases N = 1 end N = 2, that of other relations hitherto used for interpreting the compressional behaviour of different substances. Model 1 is discussed on the base of more than 70 substances with various compressional properties, among them stishovite and solid hydrogene, proved to be suitable, in particular, for the physics of the interiors of the Earth and of terrestrial planets. Considering the reliability of the data material available, Model 1 is pointed out to predict experimental values from the tested substances for volumetric contractions down to about 0.5 with a relative error between 1 % and 5 %. Model 2, extending the information volume of Model 1, turns out to be appropriate for volumetric contractions less than 0.5 as is the case in the interiors of the Jovian planets. For practical use of both models tables and graphs of sensitivities and errors of significant quantities are presented. In case data from shock-wave experiments on rocks and minerals are available, Model 1 is used for identification of crystal structures of high-pressure phases. As a result, for the majority of high-pressure phases the compressional behaviour differs from that of the corresponding oxide mixtures. For some substances new conclusions on their crystal structures can be drawn.

Beschreibung: 1. Introduction 2. Basic relations 3. Approximations for the equation of state 4. The conditions of the auxiliary variable 5. Development of Model 1 and Model 2 6. Practical analysis of the models 6. 1. Preliminaries 6.2. The parameters "0 and "1 6.3. Intercomparison of different forms of the equation of state 6.4. The parameter n2 6.5. Problems of accuracy 6.6. Discussion of [x,P]-data of elements 6.7. Discussion of [x,P]-data of halides 6.8. Discussion of [x,P]-data of oxides, minerals, and rocks 6.9. On the "interpolating equations of state" 7. Conclusion 8. Tables and Figures References

Beschreibung: A major problem in geodynamics with seismic data is discussed: How deeply do the continents penetrate into the mantle? Differential travel times of underside reflections from mantle discontinuities that appear as precursors to SS, in large parts of the globe, show a clear correlation with oceans and continents. They are significantly larger beneath the Asian and North American continents than underneath the neighbouring Pacific. From this observation we conclude that the Asian and North American continents affect the mantle well below 410 km. Changes in the thickness of the transition zone can explain our observations, which are in agreement with the hypothesis of petrological phase changes causing the 410 km and 660 km seismic discontinuities. Average thickness of the transition zone underneath continents is about 14 kim thicker than beneath oceans. Moreover, our findings imply temperature variations about 100–200 K in the mantle transition zone. Weak reflections from 520 km depth corresponding to an impedance contrast of about 2% can be observed only in some areas of the Earth, while observations from other locations definitively show no signal from this depth. Therefore, we propose that the 520 km reflector is only a regional feature.

Beschreibung: Local seismic network in Northern Chile, Southern Bolivia. (Grant-number: GIPP199604) Waveform data is available from the GEOFON data centre. License: “Creative Commons Attribution-ShareAlike 4.0 International License” (CC BY-SA).

Beschreibung: The vibroseis reflection profiling component of the URSEIS '95 experiment provides a high-resolution crustal-scale image of the unextended southern Uralide orogen. A marked lateral and vertical variation of reflectivity throughout the entire crust differentiates the former margin of the East European craton to the west from accreted terranes to the east. Between these regions is a less reflective zone corresponding to the Magnitogorsk volcanic arc and the crustal root zone. Continuous reflections and reflective domains that correlate at the surface with major tectonic features define a bivergent orogen in which the Paleozoic collisional structure has been largely preserved.

Beschreibung: Explosive-source deep seismic reflection data from the southern Ural Mountains of central Russia provided a lithosphere-scale image of the central Eurasian plate that reveals deep reflections (35 to 45 seconds in travel time; ∼130 to 170 kilometers deep) from the mantle. The data display laterally variable reflectivity at the base of the crust that deepens beneath the central part of the profile, documenting a crustal thickness of ∼55 to 60 kilometers beneath the axis of the orogen. These data provide an image of the structure of the crust and underlying mantle lithosphere in a preserved collisional orogen, perhaps to the base of the lithosphere.

Beschreibung: Analyses of magnetotelluric (Mn and magnetovariational (MV) data from 20 sites spanning southe~ Kenya has revealed significant three-dimensional effects. Consideration of both regional geology and induction arrow transfer functions implies the importance of two principal strike directions : One delineated by the N-S trending rift, the other controlled by a continental scale, Protorozoic , NW-SE striking , fault fabric. The hypothesis that the induction arrows might be explicable in terms of the near-surface expression of the conductive infill of the rift, together with a deep-seated , NW-SE striking conductor extending into the upper mantle is borne out by three-dimensional modelling . Spatially and directionally , the mantle conductor may correspond with a low velocity zone modelled from teleseismic data and both geophysical signatures may relate to a major, NW-SE striking shear zone system which has been mapped at the surface. A low velocity zone modelled from seismic refraction data recorded along a profile which crosses the rift at the same latitude as the MT measurements has been speculatively attributed to a few percent partial melt in the mantle directly below the rift. No support for this interpretation is provided by the MV data.

Beschreibung: Long period magnetotelluric and magnetovariational (MT /MV) measurements in West Bohemia carried out along the profile Cheb- Tachov- Nyrsko, close to the Czech-German border, display a striking similarity with analogous data from the immediate vicinity of the KTB borehole. On the other side, broad band AMT /MT /MV data along the seismic reflection traverse 9HR, measured by the Free Univ. of Berlin and Geofyzika Inc. Brno, show a substan tially more complex geoelectrical structme in the region to the east of the West Bohemian fault zone, indicating a discontinuous geoelectrical character when approaching the western margin of the Bohemian Massif. To assess the large scale geoelectrical changes in the E-W direction, additional long period MT measurements have been carried out at 8 localities in the area between the two basic NW-SE profiles. The new stat ions were arranged along two short profiles, one traversing the West Bohemian faults into the TeplaBarrandien zone and the other running just along the Central Bohemian deep fault. Preliminary analysis of those measurements is presented in this contribution.

Beschreibung: Variations of annual and semiannual oscillations in rotation parameters have been investigated on the basis of length-of-day (LOD) as well as atmospheric-angular-momemtum (AAM) time series. These oscillations were deter- mined using band-pass filters. In order to show the character of variations of seasonal oscillations, amplitudes, phases and periods were computed by a least-squares adjustment with the method of modified harmonic analysis at quarterly intervals. In addition, the seasonal imbalances in LOD and AAM budgets were determined and analysed in a similar way. These discrepancies were corrected for tidally excited effects. The non-atmospheric oscillations without the annual tide effect Sa and the semiannual tide effect Ssa have changeable amplitudes between 0.02 and 0.10 ms.

Beschreibung: Global Seismic Network data were used to image upper-mantle seismic discontinuities. Stacks of phases that precede the PP phase, thought to be underside reflections from the upper-mantle discontinuities at depths of 410 and 660 kilometers, show that the reflection from 410 kilometers is present, but the reflection from 660 kilometers is not observed. A continuous Lamé's constant λ and seismic parameter at the 660-kilometer discontinuity explain the missing underside P reflections and lead to a P-wave velocity jump of only 2 percent, whereas the S-wave velocity and density remain unchanged with respect to previous global models. The model deemphasizes the role of Lamé's constant λ with regard to the shear modulus and constrains the mineralogical composition across the discontinuity.

Beschreibung: The small satellite mission CHAMP was initiated and is primarily funded by the German Space Agency (DARA) as a lead project for the East German space industry. It is defined in its main mission goals by researchers of the GeoForschungsZentrum Potsdam (GFZ), and is conducted under lead of GFZ in cooperation with the German Aerospace Establishment (DLR) and the industry . After completion of an initial feasibility study (Phase A) and of the project's definition/specification phase (Phase B), followed by a two months redesign phase (Phase ~B), CHAMP is supposed to enter into Phase C/D in late 1996. CHAMP as a geoscientific mission with a multi-purpose and complementary payload shall substantially contribute to one of the basic research objectives of studies of planet Earth, that is, to the determination of the composition, structure, and dynamics of the solid planet, its oceans and atmosphere, and its surrounding envelope of charged particles and fields. CHAMP being one element in a timely sequence of Earth observations and platforms, satellites, and mini-satellites could be a contributor to the acquisition of global, synoptic and long-term measurements of global processes through space and ground instrumentation . CHAMP shall fulfil the criteria of a small satellite mission, i.e., only a few years of development time through the usage of existing sensors and commercial spacecraft subsystem components, and reduced costs through protoflight approach, reduced quality standards and test efforts. The most challenging parts of the CHAMP mission are the variety of payload components especially the accelerometer and the magnetometers, each one with demanding environmental requirements. It is designed to observe both the gravitational as well as the magnetic potential from one platform in order to get a complementary scientific payback. The GPS-receiver on-board CHAMP being employed for gravity field recovery, simultaneously will perform atmosphere and ionosphere profiling by Earth limb sounding. It is also for the first time a three-axes accelerometer will be flown to measure with a required accuracy of 10^8m/s2 the non-gravitational forces, e.g. air drag, perturbing the satellite's motion.

Beschreibung: The goal of the BEECD project is to prepare a basic parametric earthquake catalogue of Europe and a database of primary data, with special reference to long-term seismicity. This paper discusses the background of the project, with special reference to the reasons and the procedures according to which the catalogue and the database will be compiled. In the following the first results of the project are presented: first, procedures and problems in the compilation of the working file, including the analysis of the input catalogues; next, the definition of a tool for classifying the supporting data sets and its application to the entries of the input catalogue for the time-window before 1990, which shows that the average quality of the supporting data is rather poor; finally, some results of earthquake investigation, some potential use and the expected results.

Beschreibung: In the discourse about sustainable development, "constant natural capital" is frequently referred to as a criterion for ecological sustainability. But what is "natural capital"? The concept will be analyzed by presenting arguments in favour of using the term and different versions of sustainability (strong and weak). Subsequently, a critique of the "natural capital" concept is brought forward, from an ecological as well as from an economic perspective. Following this critique, the use of material inputs and the material input per unit of service (MIPS) as a measure for the environmental impact potential is suggested. Dematerialisation is understood to be an alternative management rule for sustainability. In conclusion, a change of perspective is proposed. Due to the conceptual and measurement problems associated with the "constant-natural-capital" criterion (which refers to a stock), it seems more reasonable from a scientific as well as from a practical perspective to add flows (i.e. material inputs) to a decision criterion for whether a development is sustainable or not.

Beschreibung: Sustainable development, as it emerged in Agenda 21 from the Rio conference in 1992, will only be meaningful when it touches the lives of ordinary people; then it becomes a reality. Local Agenda 21 (LA21) seeks to achieve that objective. This article assesses the origins of LA21, reviews its social and political significance, and considers its prospects in the light of case study experience emerging from the UK, Germany and Norway, focusing on the role of local government as a major stakeholder in Agenda 21 (A21). The range of response to LA21 has proved to be varied. A successful transformation to a more sustainable world will require visionary political leadership, supportive administrations, networks of experience sharing, alliances with non‐governmental organisations and local industry, and effective community mobilisation. All of that, in turn, requires equally supportive economic and social policy backing from national governments. This article will indicate that, not surprisingly, it is the domestic political context, nationally and locally, which in the main determines the speed and nature of response to LA21, now and in the future. By understanding and being aware of these contexts, factors impeding progress towards LA21 may be addressed, whilst at the same time retaining the diversity of response which is an essential part of local sustainability.

Beschreibung: This paper compares the one-sector neoclassical (Solow) growth model with a neo-Austrian growth model. The solutions of the neoclassical growth model in terms of the golden rule of accumulation and the Ramsey rule are well known, and these conditions are compared with the outcomes of the neo-Austrian growth model, which we derive using a basic three-process model.

Beschreibung: The main focus of this paper is on freight transportation and food supply in the United States and in Europe especially in Germany. Organic, resp. healthy and safe food is a growing demand in both countries. People who consume organic food often believe that this contributes to an environmentally sound behaviour. But transportation issues are not or rarely taken into consideration so far, although long distance transport not only needs energy, it as well influences quality, freshness and taste of food. On both sides of the Atlantic, in freight transportation and food supply can be found a lot of differences as well as similarities. Main differences to the U.S. from the European standpoint are e.g. the bigger land area and larger and much more concentrated economic units. Quite naturally one can find a higher volume of long distance freight transport than in Europe. Similarities can be observed, but very often they present themselves in another extent, e.g. the trend towards privatisation and liberalisation, to more extended suburbanisation or to an unreflected way of consumer behaviour. In addition, this report raises some new questions: is the ’technological solution’ of environmental problems the only way? What can be done to include lifestyles and consumer behaviour into a new strategy?