Gravity collapse structures in the Central Precordillera fold-andthrust belt, Argentina

Several landforms found in the fold-and-thrust belt area of Central Precordillera, Pre-Andes of Argentina, which were often associated with tectonic efforts, are in fact related to non-tectonic processes or gravitational superficial structures. These second-order structures, interpreted as gravitational collapse structures, have developed in the western flank of sierras de La Dehesa and Talacasto. These include rock-slides, rock falls, wrinkle folds, slip sheets and flaps, among others; which together constitute a monoclinal fold dipping between 30º and 60º to the west. Gravity collapse structures are parallel to the regional strike of the Sierra de la Dehesa and are placed in Ordovician limestones and dolomites. Their sloping towards the west, the presence of bed planes, fractures and joints; and the lithology (limestone interbedded with incompetent argillaceous banks) would have favored their occurrence. Movement of the detached structures has been controlled by lithology characteristics, as well as by bedding and joints. Detachment and initial transport of gravity collapse structures and rockslides in the western flank of the Sierra de la Dehesa were tightly controlled by three structural elements: 1) sliding surfaces developed on parallel bedded strata when dipping >30° in the slope direction; 2) Joint’s sets constitute lateral and transverse traction cracks which release extensional stresses and 3) Discontinuities fragmenting sliding surfaces.  Some other factors that could be characterized as local (lithology, structure and topography) and as regional (high seismic activity and possibly wetter conditions during the postglacial period) were determining in favoring the steady loss of the western mountain side in the easternmost foothills of Central Precordillera.

Energy transfer rates and population inversion investigation of sup(1)Gsub(4) and sup(1)Dsub(2) excited states of Tmsup(3+) in Yb:Tm:Nd:KYsub(3)Fsub(10) crystals

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Population inversion between the sup(3)Hsub(4) and the sup(3)Fsub(4) excited states of Tmsup(3+) investigated by means of numerical solutions of the rate equations system in Tmsup(3+)-doped and Tmsup(3+), Hosup(3+)-codoped fluoride glasses

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Energy transfer rates and population inversion of sup(4)Isub(11/2) excited state of Ersup(3+) investigated by means of numerical solutions of the rate equations system in Er:LiYFsub(4) crystal

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Politisations différentielles et acculturations mutuelles en contexte autoritaire : ethnographie d'une inversion du cens électoral

Français L'observation ethnographique des politisations différentielles pendant une campagne électorale en contexte autoritaire changeant est un analyseur privilégié de plusieurs processus. Sur un plan empirique, elle donne à voir les modalités diversifiées d'appropriation du moment électoral par les acteurs, les tentatives d'ajustement d'une partie de la gauche marocaine à la perte de son électorat de granit et aux transformations du marché électoral, mais également un mouvement de fond : celui de l'inversion ponctuelle du principe censitaire, en lien avec la désertion des urnes par les plus dotés culturellement et matériellement et avec la mutation du vote urbain populaire. Sur un plan théorique, l'examen des tâtonnements en oeuvre - avant leur naturalisation - permet de poursuivre le dialogue entre les travaux sur le clientélisme politique et sur la politisation, au croisement des approches socio-historiques et de sociologie politique, en contextes autoritaires et démocratiques. Il montre l'intérêt de dépasser les oppositions entre conceptions restrictives et extensives de la politisation, pour se saisir processuellement et in situ des politisations différentielles des acteurs, des registres et des pratiques. English Differential Forms of Politicization and Mutual Acculturation in an Authoritarian ContextThe ethnographic observation of differential forms of politicization during an electoral campaign in a changing authoritarian context is an ideal means of analyzing a number of processes. Empirically, it enables us to observe the actors' diverse ways of appropriating the electoral moment, a Moroccan leftist party's attempts to adjust to the loss of its electoral base and the transformations of the electoral market. It also enables us to observe a one-time reversal of the symbolic voting restrictions, in correlation with the desertion of the polls by the those best equipped to participate, both culturally and materially, and with the transformation of the urban popular vote. In theoretical terms, examination of such ongoing processes - before their stabilization - allows us to follow the interplay between the work on political clientelism and on politicization, at the intersection of sociohistorical and political sociological approaches, in authoritarian and democratic contexts. It demonstrates the value of moving beyond the opposition between restrictive and extensive conceptions of politicization, to grasp the process in situ of differential forms of the politicization of actors, registers and practices.

Geologie und Hydrogeologie im Raum Bad Pyrmont unter besonderer Berücksichtigung des Quellensystems

The hydrodynamics and hydrochemistry of salt and fresh water from solid rock aquifer systems in the Pyrmont area are described and interpreted on the basis of recent investigations including geoelectrics, isotope hydrology, soil air analysis. Theories on the source of the springs in this area are developed, which explain the different compositions of the springs and make it possible to protect them. Data from new and re-interpretated drill holes, borehole logs and outcrops suggest a revision of the geological structure of the Pyrmont dome. Bad Pyrmont is situated on a wide dome of Triassic rocks in the southern part of the Lower Saxony uplands. Inversion of the relief has caused the development of an erosional basin surrounded by prominent ridges. Deep faults developed at the crest of the dome as this part of the structure was subjected to the strongest tectonic stress. Subrosion of the Zechstein salts in the western part of the dome has caused the main salt bed to wedge out below the western part of the dome along a N-S striking structure; this structure is refered to as the „Salzhang“ (salt slope). West of the „Salzhang“, where subrosion has removed the salt bed that prevents gas rising from below, carbon dioxide of deep volcanic origin can now rise to the surface. Hydraulic cross sections illustrate the presence of extensive and deep-seated groundwater flow within the entire Pyrmont dome. While groundwater flow is directed vertically downwards in the ridges surrounding the dome, centripetal horizontal flow predominates the intermediate area. In the central part of the dome, groundwater rises to join the River Emmer, which is the main receiving water course in the central part of the eroded basin. The depth of the saltwater/freshwater interface is determinated by the weight of the superimposed freshwater body. Hydrochemical cross sections show the shape and position of the interface and document a certain degree of hydrochemical zonation of the gently mineralized fresh water. Genetic relationships between the two main water types and the hydrochemical zones of the freshwater body are discussed. The knowledge of the hydrogeological relationship in the Bad Pyrmont aquifer systems permits a spatially narrow coexistence of wells withdrawing groundwater for different purposes (medicinal, mineral, drinking and industrial water).

Idealized modeling of the role of stability and shear on mesoscale gravity wave evolution

Mesoscale Gravity Waves (MGWs) are large pressure perturbations that form in the presence of a stable layer at the surface either behind Mesoscale Convective Systems (MCSs) in summer or over warm frontal surfaces behind elevated convection in winter. MGWs are associated with damaging winds, moderate to heavy precipitation, and occasional heat bursts at the surface. The forcing mechanism for MGWs in this study is hypothesized to be evaporative cooling occurring behind a convective line. This evaporatively-cooled air generates a downdraft that then depresses the surface-based stable layer and causes pressure decreases, strong wind speeds and MGW genesis. Using the Weather Research and Forecast Model (WRF) version 3.0, evaporative cooling is simulated using an imposed cold thermal. Sensitivity studies examine the response of MGW structure to different thermal and shear profiles where the strength and depth of the inversion are varied, as well as the amount of wind shear. MGWs are characterized in terms of response variables, such as wind speed perturbations (U'), temperature perturbations (T'), pressure perturbations (P'), potential temperature perturbations (Θ'), and the correlation coefficient (R) between U' and P'. Regime Diagrams portray the response of MGW to the above variables in order to better understand the formation, causes, and intensity of MGWs. The results of this study indicate that shallow, weak surface layers coupled with deep, neutral layers above favor the formation of waves of elevation. Conversely, deep strong surface layers coupled with deep, neutral layers above favor the formation of waves of depression. This is also the type of atmospheric setup that tends to produce substantial surface heating at the surface.

Soil characteristics in Doon Valley (north west Himalaya, India) by inversion of H/V spectral ratios from ambient noise measurements

Past and recent observations have shown that the local site conditions significantly affect the behavior of seismic waves and its potential to cause destructive earthquakes. Thus, seismic microzonation studies have become crucial for seismic hazard assessment, providing local soil characteristics that can help to evaluate the possible seismic effects. Among the different methods used for estimating the soil characteristics, the ones based on ambient noise measurements, such as the H/V technique, become a cheap, non-invasive and successful way for evaluating the soil properties along a studied area. In this work, ambient noise measurements were taken at 240 sites around the Doon Valley, India, in order to characterize the sediment deposits. First, the H/V analysis has been carried out to estimate the resonant frequencies along the valley. Subsequently, some of this H/V results have been inverted, using the neighborhood algorithm and the available geotechnical information, in order to provide an estimation of the S-wave velocity profiles at the studied sites. Using all these information, we have characterized the sedimentary deposits in different areas of the Doon Valley, providing the resonant frequency, the soil thickness, the mean S-wave velocity of the sediments, and the mean S-wave velocity in the uppermost 30 m.

AMPLITUDE-VERSUS-ANGLE ANALYSIS AND WIDE-ANGLE-INVERSION OF CROSSWELL SEISMIC DATA IN A CARBONATE RESERVOIR

Crosswell data set contains a range of angles limited only by the geometry of the source and receiver configuration, the separation of the boreholes and the depth to the target. However, the wide angles reflections present in crosswell imaging result in amplitude-versus-angle (AVA) features not usually observed in surface data. These features include reflections from angles that are near critical and beyond critical for many of the interfaces; some of these reflections are visible only for a small range of angles, presumably near their critical angle. High-resolution crosswell seismic surveys were conducted over a Silurian (Niagaran) reef at two fields in northern Michigan, Springdale and Coldspring. The Springdale wells extended to much greater depths than the reef, and imaging was conducted from above and from beneath the reef. Combining the results from images obtained from above with those from beneath provides additional information, by exhibiting ranges of angles that are different for the two images, especially for reflectors at shallow depths, and second, by providing additional constraints on the solutions for Zoeppritz equations. Inversion of seismic data for impedance has become a standard part of the workflow for quantitative reservoir characterization. Inversion of crosswell data using either deterministic or geostatistical methods can lead to poor results with phase change beyond the critical angle, however, the simultaneous pre-stack inversion of partial angle stacks may be best conducted with restrictions to angles less than critical. Deterministic inversion is designed to yield only a single model of elastic properties (best-fit), while the geostatistical inversion produces multiple models (realizations) of elastic properties, lithology and reservoir properties. Geostatistical inversion produces results with far more detail than deterministic inversion. The magnitude of difference in details between both types of inversion becomes increasingly pronounced for thinner reservoirs, particularly those beyond the vertical resolution of the seismic. For any interface imaged from above and from beneath, the results AVA characters must result from identical contrasts in elastic properties in the two sets of images, albeit in reverse order. An inversion approach to handle both datasets simultaneously, at pre-critical angles, is demonstrated in this work. The main exploration problem for carbonate reefs is determining the porosity distribution. Images of elastic properties, obtained from deterministic and geostatistical simultaneous inversion of a high-resolution crosswell seismic survey were used to obtain the internal structure and reservoir properties (porosity) of Niagaran Michigan reef. The images obtained are the best of any Niagaran pinnacle reef to date.