Shape analysis and multispectral classification in geological remote sensing

This paper discusses the usage of mathematical morphology in image processing of remotely-sensed data for geologic interpretation. Particular attention is given to noise-reducing transformations of spectral bands before and after different methods of classification, and to the usage of textural context. The development of a viable processing strategy requires a multidisciplinary approach and expert knowledge in different areas: (a) geology, geomorphology, and vegetation in a study area, (b) properties of the sensor for imagery photointerpretation, (c) spectral/spatial properties of the digital data within an integrated dataset (remote sensing and ancillary data), and (d) data-processing tools including mathematical morphology theory. Examples of geometric characterization of Canadian LANDSAT scenes are described in which shape measurements are obtained using a PC-based hybrid image-processing and geographic information system, termed ILWIS, which was developed at ITC, in the Netherlands. Classes from supervised and unsupervised classification are compared to guide in geological mapping. Classes over individual occurrences of broad vegetation-landform units are studied to aid in environmental mapping. Field knowledge is the context necessary to construct expert procedures to drive sequences of data-processing steps toward a target result such as optimal classification, enhancement, or feature extraction. The interaction between expert rules and the image-processing steps can be based on synthetic measurements of shape to quantize the information either spatially or spectrally. Many useful geometrical transformations of spatially-distributed data are extensions or generalizations of spatial analysis functions typical of geographic information systems.     

A Geostatistical Simulation Approach to a Pollution Case in Northeastern Italy

The study zone is located in the city of Padova (the Veneto region, NE Italy). The industrial activities present in this area since 1950 have produced very high concentrations of Pb, Zn, Cu, Pcb and oils until a depth of 7 m. The unsaturated and the saturated zones are both polluted. Because of the abundance of Pb values it was decided to analyze the lead distribution in the studied zone. In many studies of the polluted sites, the geometry of the investigated volume is highly anisotropic. Generally we have an extension of some hectares in the horizontal plane and of a few meters in depth. It is likely that different horizontal spatial continuity structures in pollution distribution are found at different depths both for the layered nature of the medium and for the transition between unsaturated and saturated conditions. In such conditions the decision to divide a 3D problem into 1D and 2D problems can be useful. Initially the studied volume was divided into seven layers up to 5 m in depth; the study was then approached in two phases. First, the Pb values in the vertical direction were analyzed, considering a derive along z, and estimating the values using the Kriging with Trend (KT) method. Thus it was possible to increase the data in the z direction, especially in the deeper layers. Second, 500 realizations of the Pb distribution for each of the seven layers were simulated using the simulated annealing procedure. Finally, results were presented and discussed for each layer in terms of median and probability maps.     

Galactic halos,globular clusters and massive neutrinos

Within the framework of a Gamow cosmology with massive neutrinos a scenario is proposed in which both galactic halos and globular clusters are formed due to the existence of a critical injection mass. Galactic halos are formed at red shift z10–100 by self-gravitating neutrinos, and globular clusters atz10³ by a critical injection mass of primordial plasma (Gamow's Ylem).     

Critical evaluation of an intercalibration exercise undertaken in the framework of the MED POL biomonitoring program.

The results of an intercalibration exercise among the laboratories participating in the MED POL program for monitoring biological effects of pollutants along the Mediterranean coasts are presented. Three established biomarkers, i.e. lysosomal membrane stability, metallothionein concentration and ethoxyresorufin-O-deethylase (EROD) activity, were intercalibrated. The stability of lysosomal membranes in mussels (Mytilus galloprovincialis Lam.) was assessed with a cytochemical method. The four participating laboratories were able to discriminate between control animals (membrane labilization times ranging from 21 to 35 min) and Cu-exposed animals (40 micrograms/l Cu for 3 days) (labilization times ranging from 4.5 to 7.4 min). The metallothionein concentration was evaluated in digestive gland homogenates of control mussels and of animals exposed to 200 micrograms/l Cd for 7 days. The eight participating laboratories were able to discriminate between controls and treated samples using a spectrophotometric method. The EROD activity was evaluated by 11 laboratories. All laboratories were able to discriminate between liver microsomal preparations obtained from control and from benzo-a-pyrene exposed fish (Dicentrarchus labrax), with values ranging from 0.5 to 15.88 pmol/min/mg protein in controls and from 5.41 to 165.13 pmol/min/mg protein in treated animals. Using S9 fractions, it was possible to correctly identify control and treated fish, with a variation similar to that found using microsomal fractions, albeit with an inevitable difference in specific activity. As a corollary, all laboratories involved produced comparable data and were able to identify pollutant-induced stress syndromes in sentinel organisms. Thus, intercalibration enables the use of biomarkers in large biomonitoring programs.     

Spectrum of the Sunyaev-Zel'dovich effect for high electron temperatures

We analyse in detail the spectral shape of the Sunyaev-Zel'dovich effect in the cosmic background radiation, taking into account the relativistic corrections for a hot electron gas. We calculate the displacement of the zero-signal frequency, which is especially informative in a new method for measuring the millimetric temperature of the background radiation; we also present a simple analytical expression, to be used to fit the experimental data in spectral measurements of the effect in very hot cluster gases.     

Pseudotachylytes in the Balmuccia peridotite (Ivrea Zone) as markers of the exhumation of the southern Alpine continental crust

Two types of pseudotachylytes are observed in the Balmuccia peridotite of the Ivrea zone (Southern Alps, Italy). A-type pseudotachylytes correspond to previously studied occurrences and were formed under temperatures comprising between 550 and 900 °C and pressures comprising between 0.6 and 1.2 GPa. These conditions were met in the Ivrea crust between 350 and 270 Ma, suggesting that A-type pseudotachylytes were formed during Variscan tectonics or Permian transtensional tectonics. B-type pseudotachylytes post-date A-type pseudotachylytes. Textural characteristics of B-type veins suggest a formation in the upper continental crust, at depths of about 5–10 km or less. Petrological constraints indicate that the exhumation of the Ivrea crust at such shallow depths was achieved later than c.  70 Ma, thus providing a maximum age of 70 Ma for B-type veins. Pseudotachylytes appear as markers of the poly-orogenic evolution of the Alpine belt.     

Contents of Volume 30

Volume Contents

Contents of Volume 30