Combination of historical maps and satellite images of the Banat region—Re-appearance of an old wetland area

The area of Banat, a historical region shared by Romania and Serbia, has been hit by a centennial flood event in spring 2005. The Temes (Tamiš/Timiş) River flooded several hundred km², with many settlements. The extent of the flood was partly unexpected, especially in positional sense. In order to achieve a better understanding of the phenomenon, we analysed the SRTM digital elevation model as well as historical maps. Several historical maps, dating back to the 16th century, indicate marshland or even a large lake in the area, not existing today but almost exactly coinciding with the extent of the 2005 flood.The historical and archive maps document the water regulation measures taken since the early 19th century. The actual flood is found to be a sort of a restoration of the original natural conditions. Via the analysis of the DEM and historical maps the unexpected extent of the flood scenario can be explained and understood. We suggest that an analysis of historical and archive maps, combined (geo-referenced) with high-resolution DEMS in other flood-endangered areas, should be used in order to be better prepared for decadal or centennial flood events induced by climatic change.     

Poisson's ratio of eclogite: Implications for lower crustal delamination of orogens

Eclogite is essentially a bi-mineralogic high-grade metamorphic rock consisting of garnet and omphacite and is the product of high-to-ultrahigh pressure metamorphism of basaltic rocks due to the subduction of oceanic crust or the thickening/subduction of …     

Über Beanspruchung und Verformung von Gesteinen

7 coaxial (p ₁>p ₂=p ₃) and 6 real triaxial (p ₁>p ₂>p ₃) compression tests (0,5 to 6 hours duration) on cubic samples of homogeneous, statistically low anisotropic marble from Auerbach (Germany) were made at room temperature and different ratios of the main pressures and rates of loading. 3 samples of strong anisotropic marble of Drama (Greece) were deformed at p ₁p ₂p ₃=841 and constant rate of loading in the three orientations: parallel, at 45° and perpendicular to the foliation (12 hours duration). As can be deduced from the orientation diagrams, the deformation proceeds mainly by twin gliding. In most of the tests reported here the symmetry of the external loading (coaxial or orthorhombic) can be correlated with the symmetry of the orientation diagrams. Real triaxial deformation (P ₁Nep ₂Nep ₃) produces two sets of planes ± perpendicular to each other as B B. In the tests with the strong anisotropic material the strain was measured in the three main directions and plotted as strain-time curves. When the foliation is oriented perpendicularly or even obliquely to p ₁ compression dominates at the beginning in the direction of the intermediate loading p ₂ producing preferred orientation of the twin lamellae. Later on there is compression in p ₁ and extension in p ₂ and p ₃. This phase of deformation is characterized by brittle fracture and increase of volume.     

Über Beanspruchung und Verformung von Gesteinen

A new real triaxial deformation apparatus for p ₁p ₂p ₃ tests and temperatures up to 700° C has been developed. In five creep tests over 8 hours the strain-time curves at 650° C for axial and orthorhombic symmetry of stress are plotted in the three main directions and compared with the petrofabric diagrams of the deformed material. In all tests the symmetry of the petrofabrics can be correlated with the symmetry of the external loading. From the strain-time curves it can be deduced that the intermediate loading p ₂ is of great influence in the stress-strain behavior.Syntectonic recrystallization is found to be common for all tests in the form of broad lensoid and irregular defined {01¯12} lamellae oriented favorably for twinning. Measurements of c-axes in newly recrystallized grains show preferential alingnement subparallel to the axis of maximum principal loading.

---

---

Der Deutschen Forschungsgemeinschaft sei für die finanzielle Unterstützung der Untersuchungen besonders gedankt.     

The effect of a deviatoric stress on physical rock properties

Petrophysical measurements were carried out on dry specimens of mica-gneiss, amphibolite and serpentinite from KTB core samples and samples of surface outcrops in order to determine the effect that a deviatoric stress field, as observed at the KTB area, may have on the in-situ rock properties. Simulating the variation of the actual principal stresses and temperature with depth, seismic wave velocities, densities, linear and volumetric strain (porosity) have been measured, taking into account the overall spatial orientation of the foliation at the KTB area with respect to the principal stress axes. Comparison with respective data evaluated for lithostatic pressure conditions revealed that the stress-related (crack-related) effect on wave velocities respectively on velocity anisotropy is in the range 1–3%, due to microcracks which are selectively closed or kept open by the deviatoric stress. The effect of the deviatoric stress is particularly documented by shear wave splitting due to microfractures that are oriented normal to the minimum principal stress axis.     

Capillary waves understood by an elementary method

The central physics of capillary waves (or ripples) can be understood by an elementary method which makes use of the balance of static and dynamic pressure differences along the surface streamline between crest and trough, in the steady reference frame, and conservation of mass through vertical cross-sections beneath crest and trough. Basically Einstein’s (1916) model of surface gravity waves is adapted for the purpose of explaining the existence of capillary waves of infinitesimal amplitude. One product of the physical understanding, the phase speed of capillary waves, is derived as a function of the wave length and surface tension and the result agrees exactly with that obtained by the classical mathematical procedure. In the elementary method it is not necessary to assume irrotational flow, upon which the classical theory is founded, nor are perturbation expansions of the nonlinear fluid equations employed. The extension to capillary-gravity waves, by including the acceleration of gravity in the physical model, is straightforward, and the calculated phase speed of these waves is identical to what is found in the text books as well.     

Structure and composition of the continental crust in East China

Crustal structures of nine broad tectonic units in China, except the Tarim craton, are derived from 18 seismic refraction profiles including 12 geoscience transects. Abundances of 63 major, trace and rare earth elements in the upper crust in East China are estimated. The estimates are based on sampling of 11 451 individual rock samples over an area of 950 000 km², from which 905 large composite samples are prepared and analyzed by 13 methods. The middle, lower and total crust compositions of East China are also estimated from studies of exposed crustal cross sections and granulite xenoliths and by correlation of seismic data with lithologies. All the tectonic units except the Tarim craton and the Qinling orogen show a four-layered crustal structure, consisting of the upper, middle, upper lower, and lowermost crusts. P-wave velocities of the bulk lower crust and total crust are 6.8–7.0 and 6_:4–6.5 km/s, respectively. They are slower by 0.2–0.4 km/s than the global averages. The bulk lower crust is suggested to be intermediate with 58% SiO₂ in East China. The results contrast with generally accepted global models of mafic lower crusi. The proposed total crust composition in East China is also more evolved than previous estimates and characterized by SiO₂=64%, a significant negative Eu anomaly (Eu/Eu* = 0.80), deficits in Sr and transition metals, a near-arc magma La/Nd ratio (3.0), and a calculatedμ(²³⁸U/²⁰⁴Pb) value of 5. In addition, it has the following ratios of element pairs exhibiting similar compatibility, which are identical or close to the primitive mantle values: Zr/Hf=37, Nb/Ta=17.5, Ba/Th=87, K/Pb=0.12x10⁴, Rb/Cs=25, Ba/Rb=8.94, Sn/Sm=0.31, Se/Cd=1.64, La/ As=10.3, Ce/Sb=271, Pb/Bi=57, Rb/TI=177, Er/Ag=52, Cu/Au=3.2×10⁴, Sm/Mo=7.5, Nd/W=40, CI/Li=10.8, F/Nd=21.9, and La/B=1.8. Project supported by the National Natural Science Foundation of China (Grant Nos. 49625305, 49573183, 49673184, 49794043), the State Comission of Education, the Ministry of Geology and Mineral Resources of China (Grant No. 850514), the Open Laboratory of Constitution, Interaction and Dynamics of the Crust-Mantle System, and the Alexander-von-Humboldt Foundation of Germany.     

Emergence of an Integrated Softcopy Stereoplotter System to Replace Analogue Stereoplotters

Stereoscopic softcopy photogrammetric systems were originally as expensive as analytical stereoplotters, which prohibited their use in most small production firms. At the lower end of the cost spectrum, the functioning of these systems has previously been somewhat limited. Advances in computing technology and software architecture have now made an economic replacement of analogue stereoplotters a reality. A reasonably priced, high performance, off the shelf production solution is now possible on standard PC hardware. This paper provides a comparison of analogue and digital photogrammetry for a production work flow, commencing after scanning the films and progressing through project set up, orientations, stereodisplay and feature collection, DTM collection and editing, finally ending prior to orthophotography production. The underlying breakthrough software architecture making an effective digital system possible at moderate cost is described in detail and the benefits of such a system compared with analogue plotters are highlighted.     

Pluto's Atmosphere And A Targeted-Occultation Search For Other Bound Kbo Atmospheres

Processes relevant to Pluto's atmosphere are discussed,and our current knowledge is summarized, including results of two stellar occultationsby Pluto that were observed in 2002. The question of whether other Kuiper belt objects (KBOs)may have bound atmospheres is considered, and observational indicators for KBO atmospheresare described. The definitive detection of a KBO atmosphere could be established withtargeted stellar-occultation observations. These data can also establish accurate diametersfor these objects and be used to detect possible nearby companions. Strategies for acquiringoccultation data with portable, airborne, and fixed telescopes are evaluated in terms of thenumber of KBO occultations per year that should be observable. For the sample of 29 currentlyknown KBOs with H ≤ 5.2, (radius ≤ 300 km for a geometricalbedo of 0.04), we expect about 4 events per year would yield good results for a (stationary) 6.5-m telescope. A network of portable0.36-m telescopes should be able to observe 6 events per year, and a 2.5-m airborne telescopewould have about 200 annual opportunities to observe KBO occultations.