Researches concerning the Quaternary sedimentary dynamics in the European Alps have become of increasing interest in the late decades, producing a large volume of literature. This thesis uses high-resolution seismic reflection data and seismic stratigraphic methods to examine the formation and evolution of a major alluvial/glacial fan in the eastern Italian Alps. Alluvial fan environments, often pose significant challenges for high-resolution seismic exploration, due to high heterogeneity of deposits and rugged topography. Using both non-conventional field (dense wide aperture array) and processing techniques (Common Reflection Surface stack), we were able to obtain high-quality seismic reflection and refraction images across a representative transect of Venosta Valley. By using stratigraphic, geophysical and morphologic data this work characterizes the fan and valley deposits and their evolution throughout post-glacial times. Using this information, we model the evolution of the valley fill in the framework of post-glacial climate fluctuations. The results provide an understanding of the landscape geomorphic evolution in response to the main climatic changes and also can represent a tool in policy decision regarding natural hazards.

No description available.

Il lavoro è incentrato sull’applicazione ed integrazione di differenti tecniche di indagine geofisica in campo ambientale e ingegneristico/archeologico. Alcuni esempi sono stati descritti al fine di dimostrare l’utilità delle metodologie geofisiche nella risoluzione di svariate problematiche. Nello specifico l’attenzione è stata rivolta all’utilizzo delle tecniche del Ground Penetrating Radar e del Time Domain Reflectometry in misure condotte su un corpo sabbioso simulante una Zona Insatura. L’esperimento è stato realizzato all’interno di un’area test costruita presso l’azienda agricola dell’Università La Tuscia di Viterbo. Hanno partecipato al progetto le Università di Roma Tre, Roma La Sapienza, La Tuscia, con il supporto tecnico della Sensore&Software. Nello studio è stato condotto un approccio definito idrogeofisico al fine di ottenere informazioni da misure dei parametri fisici relativi alla Zona Insatura simulata nell’area test. Il confronto e l’integrazione delle due differenti tecniche di indagine ha offerto la possibilità di estendere la profondità di indagine all’interno del corpo sabbioso e di verificare l’utilità della tecnica GPR nello studio degli effetti legati alle variazioni del contenuto d’acqua nel suolo, oltre a determinare la posizione della superficie piezometrica per i differenti scenari di saturazione. Uno specifico studio è stato realizzato sul segnale radar al fine di stabilire i fattori di influenza sulla sua propagazione all’interno del suolo. Il comportamento dei parametri dielettrici nelle condizioni di drenaggio e di imbibizione del corpo sabbioso è stato riprodotto attraverso una modellizzazione delle proprietà dielettriche ed idrologiche sulla base della dimensione, forma e distribuzione dei granuli di roccia e pori, nonché sulla base della storia relativa alla distribuzione dei fluidi di saturazione all’interno del mezzo. La modellizzazione è stata operata sulle basi concettuali del Differential Effective Medium Approximation.

No description available.

No description available.

Understanding the complex relationships between quantities measured by volcanic monitoring network and shallow magma processes is a crucial headway for the comprehension of volcanic processes and a more realistic evaluation of the associated hazard. This question is very relevant at Campi Flegrei, a volcanic quiescent caldera immediately north-west of Napoli (Italy). The system activity shows a high fumarole release and periodic ground slow movement (bradyseism) with high seismicity. This activity, with the high people density and the presence of military and industrial buildings, makes Campi Flegrei one of the areas with higher volcanic hazard in the world. In such a context my thesis has been focused on magma dynamics due to the refilling of shallow magma chambers, and on the geophysical signals detectable by seismic, deformative and gravimetric monitoring networks that are associated with this phenomenologies. Indeed, the refilling of magma chambers is a process frequently occurring just before a volcanic eruption; therefore, the faculty of identifying this dynamics by means of recorded signal analysis is important to evaluate the short term volcanic hazard. The space-time evolution of dynamics due to injection of new magma in the magma chamber has been studied performing numerical simulations with, and implementing additional features in, the code GALES (Longo et al., 2006), recently developed and still on the upgrade at the Istituto Nazionale di Geofisica e Vulcanologia in Pisa (Italy). GALES is a finite element code based on a physico-mathematical two dimensional, transient model able to treat fluids as multiphase homogeneous mixtures, compressible to incompressible. The fundamental equations of mass, momentum and energy balance are discretised both in time and space using the Galerkin Least-Squares and discontinuity-capturing stabilisation technique. The physical properties of the mixture are computed as a function of local conditions of magma composition, pressure and temperature.The model features enable to study a broad range of phenomenologies characterizing pre and sin-eruptive magma dynamics in a wide domain from the volcanic crater to deep magma feeding zones. The study of displacement field associated with the simulated fluid dynamics has been carried out with a numerical code developed by the Geophysical group at the University College Dublin (O’Brien and Bean, 2004b), with whom we started a very profitable collaboration. In this code, the seismic wave propagation in heterogeneous media with free surface (e.g. the Earth’s surface) is simulated using a discrete elastic lattice where particle interactions are controlled by the Hooke’s law. This method allows to consider medium heterogeneities and complex topography. The initial and boundary conditions for the simulations have been defined within a coordinate project (INGV-DPC 2004-06 V3_2 “Research on active volcanoes, precursors, scenarios, hazard and risk - Campi Flegrei”), to which this thesis contributes, and many researchers experienced on Campi Flegrei in volcanological, seismic, petrological, geochemical fields, etc. collaborate. Numerical simulations of magma and rock dynamis have been coupled as described in the thesis. The first part of the thesis consists of a parametric study aimed at understanding the eect of the presence in magma of carbon dioxide in magma in the convection dynamics. Indeed, the presence of this volatile was relevant in many Campi Flegrei eruptions, including some eruptions commonly considered as reference for a future activity of this volcano. A set of simulations considering an elliptical magma chamber, compositionally uniform, refilled from below by a magma with volatile content equal or dierent from that of the resident magma has been performed. To do this, a multicomponent non-ideal magma saturation model (Papale et al., 2006) that considers the simultaneous presence of CO2 and H2O, has been implemented in GALES. Results show that the presence of CO2 in the incoming magma increases its buoyancy force promoting convection ad mixing. The simulated dynamics produce pressure transients with frequency and amplitude in the sensitivity range of modern geophysical monitoring networks such as the one installed at Campi Flegrei . In the second part, simulations more related with the Campi Flegrei volcanic system have been performed. The simulated system has been defined on the basis of conditions consistent with the bulk of knowledge of Campi Flegrei and in particular of the Agnano-Monte Spina eruption (4100 B.P.), commonly considered as reference for a future high intensity eruption in this area. The magmatic system has been modelled as a long dyke refilling a small shallow magma chamber; magmas with trachytic and phonolitic composition and variable volatile content of H2O and CO2 have been considered. The simulations have been carried out changing the condition of magma injection, the system configuration (magma chamber geometry, dyke size) and the resident and refilling magma composition and volatile content, in order to study the influence of these factors on the simulated dynamics. Simulation results allow to follow each step of the gas-rich magma ascent in the denser magma, highlighting the details of magma convection and mixing. In particular, the presence of more CO2 in the deep magma results in more ecient and faster dynamics. Through this simulations the variation of the gravimetric field has been determined. Afterward, the space-time distribution of stress resulting from numerical simulations have been used as boundary conditions for the simulations of the displacement field imposed by the magmatic dynamics on rocks. The properties of the simulated domain (rock density, P and S wave velocities) have been based on data from literature on active and passive tomographic experiments, obtained through a collaboration with A. Zollo at the Dept. of Physics of the Federici II Univeristy in Napoli. The elasto-dynamics simulations allow to determine the variations of the space-time distribution of deformation and the seismic signal associated with the studied magmatic dynamics. In particular, results show that these dynamics induce deformations similar to those measured at Campi Flegrei and seismic signals with energies concentrated on the typical frequency bands observed in volcanic areas. The present work shows that an approach based on the solution of equations describing the physics of processes within a magmatic fluid and the surrounding rock system is able to recognise and describe the relationships between geophysical signals detectable on the surface and deep magma dynamics. Therefore, the results suggest that the combined study of geophysical data and informations from numerical simulations can allow in a near future a more ecient evaluation of the short term volcanic hazard.

In this thesis Marsili back-arc basin and Palinuro Volcanic Complex (Southern Tyrrhenian Sea) have been investigated by using magnetic, bathymetric and gravimetric data. A new velocity model of opening of the Marsili basin has been proposed, highlighting the transition from the horizontal spreading of the back-arc to the vertical accretion of the Marsili seamount. Introducing gravity data, Marsili's internal structure has been modeled and a huge portion of the volcano with low density and vanishing magnetization has been detected. Forward modeling of Palinuro Volcanic Complex showed as Palinuro represents the shallowest evidence of a deep tectonic discontinuity and the possible transition domain between the oceanic crust of Marsili Basin and the continental crust related to the Appenninic chain.

Made available in DSpace on 2014-06-11T19:26:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-10-25Bitstream added on 2014-06-13T18:29:46Z : No. of bitstreams: 1 demario_afg_me_rcla.pdf: 2466919 bytes, checksum: 86b229ab00f7afbb9a69e932288cdeb7 (MD5) / Este trabalho discute o emprego dos métodos geofísicos no estudo de águas subterrâneas no município de Araçariguama-SP na área do Condomínio Residencial Villa Verde que está geologicamente localizado sobre o Granitóide São Roque e os metassedimentos da Formação Serra do Itaberaba (xistos argilosos). Diante deste contexto geológico o modelo de aqüífero considerado na área do condomínio é o fraturado, tornando-se importante a caracterização estrutural do maciço rochoso com ênfase nas descontinuidades. No condomínio Villa Verde existem dois poços artesianos, sendo que o primeiro foi feito durante a construção do condomínio e o segundo poço foi perfurado em 2002, quando o consumo de água do condomínio se tornou maior que a capacidade de produção do primeiro poço. Após a realização de um estudo geológico e geofísico para determinar a melhor localização do poço na área do condomínio, ele foi locado e perfurado, mas o poço não produziu água. Visando a problemática da água na região e as dificuldades de exploração em ambiente de aqüífero fraturado, este trabalho buscou integrar estudos geológicos e estruturais com dados de poços perfurados na região, com o intuito de dar suporte à programação e interpretação dos ensaios geofísicos. Os estudos desenvolvidos neste trabalho tiveram um foco prático e voltado para a definição de estruturas com potencial para abrigar um aqüífero do tipo fraturado, utilizando a geofísica como ferramenta para investigar essas estruturas em subsuperficie, auxiliando na avaliação de viabilidade do alvo definido que, para este estudo, foi o Condomínio Villa Verde / This work discuss the use of geophysics methods in the study of groundwater in the city of Araçariguama – SP, specifically in the area of Condomínio Residencial Villa Verde that is geologically located over the São Roque granitoid and the shales of Serra do Itaberaba Formation. Because of this geological context, the considered aquifer model is fractured, making important emphasize the descontinuity in the structural characterization of bedrock. There are in the Villa Verde two boreholes, the first one was done during the construction of Villa Verde and the second one was drilled in 2002 when the first borehole could not support the demand for water in Villa Verde anymore. After a geological and geophysical study in the area to determine the best location for the borehole, it was perforated but did not produced water. Considering the problems with water in this area and the exploration difficulties of fractured aquifers, this work seeks the integration of geological and structural studies with dates boreholes in the region where the area is located. The aim is support the interpretation and program of geophysical survey. This study had a practical focus that aimed the definition of potential structures able to have a fractured aquifer. The use here of geophysics as a resource to investigate these structures in the ground intend to be an auxiliary to evaluate the viability of defined target, which for this study were the “Condomínio Villa Verde”

Orientador: Walter Malagutti Filho / Banca: Antonio Celso de Oliveira Braga / Banca: Alberto Pacheco / Resumo: Este trabalho investigou e mapeou a contaminação por necrochorume da água subterrânea no aqüífero freático do cemitério de Vila Rezende, situado na zona norte do município de Piracicaba - São Paulo, Brasil. Para tanto, foi aplicado o método da eletrorresistividade, por meio das técnicas de sondagem elétrica vertical (SEV) e imageameanto elétrico (2D), arranjos schlumberger e dipolo-dipolo respectivamente, sendo a primeira com objetivo de estudar a distribuição do parâmetro resistividade elétrica verticalmente (1D) e a outra verticalmente e horizontalmente (2D e 3D). Os resultados da SEV indicam uma profundidade do nível freático entre 3,1 e 5,1 m na época de estiagem, com dois sentidos de fluxo subterrâneo, sendo um sentido a SW e o outro a SE. A subsuperfície do cemitério apresenta uma camada pouco espessa de aterro com sedimentos de textura arenosa, predominando logo abaixo sedimentos argilosos da Formação Corumbataí e diabásio das Intrusivas Básicas respectivamente. O cemitério apresenta condições fisico-químicas dos materiais em subsuperfície desfavoráveis para percolação do necrochorume, mas facilita o fenômeno de saponificação dos cadáveres. Os resultados obtidos das linhas de imageamento elétrico (2D) indicam duas prováveis plumas de contaminante em zona não-saturada, uma na direção SW e outra a SE, ambas seguindo a direção do fluxo subterrâneo. Mas em zona saturada predomina uma pluma a SE sob as quadras Q - 08, 04 e 01, e também fora dos limites do cemitério. As áreas com baixa resistividade (anomalia condutiva), apresentadas nas seções geoelétricas e nos mapas de resistividade elétrica, demonstram que a contaminação tem ligação com a profundidade do nível freático e com o tempo de sepultamento. Por meio dos resultados obtidos, como localização e expansão das prováveis plumas, foram locados seis poços de monitoramento. / Abstract: This work investigated and mapped the contamination for necrochorume of the groundwater in the freatic aquifer of Vila Rezende's cemetery, located in the north area from Piracicaba - São Paulo, Brazil. For that, electrical resistivity method was applied using vertical electric sounding (VES) and 2D electrical imaging techniques, schlumberger and dipole-dipole arrays respectively, being the first with the objective to investigate the electric resistivity vertically (1D) and the other vertically and horizontally (2D and 3D). The results of VES indicate a depth of water table among 3,1 and 5,1 m in drought, with two flow directions, being a the SW and another the SE. Cemetery underground presents a fine layer of embankment with sediments of sandy texture, prevailing soon lowers clayey sediments of the Corumbataí Formation and diabase of the Basic Intrusive respectively. The cemetery presents physicalchemistry geological conditions unfavorable for percolation of the necrochorume, but facilitates the phenomenon of human corpse saponification. The obtained results of the lines of electrical imaging (2D) indicate two probable contamination plume in unsaturated zone, a in SW and another to SE direction, both following the groundwater flow. But in saturated zone prevails a plume at SE under the blocks Q - 08, 04 and 01, and also out of the cemetery of the limits. The areas with low resistivity (conductive anomaly), presented in the geoelectrical sections and in the electrical resistivity maps, demonstrate that the contamination has connection with the depth of the water table and time of burial. Through the obtained results, as location and expansion of the probable plumes, were suggested six monitoring wells. The applied methods in this work demonstrated as an important indirect instrument for evaluation of the environmental quality in cemeteries. / Mestre

Orientador: João Carlos Dourado / Banca: Noberto Morales / Banca: José Domingos Faraco Gallas / Resumo: Este trabalho discute o emprego dos métodos geofísicos no estudo de águas subterrâneas no município de Araçariguama-SP na área do Condomínio Residencial Villa Verde que está geologicamente localizado sobre o Granitóide São Roque e os metassedimentos da Formação Serra do Itaberaba (xistos argilosos). Diante deste contexto geológico o modelo de aqüífero considerado na área do condomínio é o fraturado, tornando-se importante a caracterização estrutural do maciço rochoso com ênfase nas descontinuidades. No condomínio Villa Verde existem dois poços artesianos, sendo que o primeiro foi feito durante a construção do condomínio e o segundo poço foi perfurado em 2002, quando o consumo de água do condomínio se tornou maior que a capacidade de produção do primeiro poço. Após a realização de um estudo geológico e geofísico para determinar a melhor localização do poço na área do condomínio, ele foi locado e perfurado, mas o poço não produziu água. Visando a problemática da água na região e as dificuldades de exploração em ambiente de aqüífero fraturado, este trabalho buscou integrar estudos geológicos e estruturais com dados de poços perfurados na região, com o intuito de dar suporte à programação e interpretação dos ensaios geofísicos. Os estudos desenvolvidos neste trabalho tiveram um foco prático e voltado para a definição de estruturas com potencial para abrigar um aqüífero do tipo fraturado, utilizando a geofísica como ferramenta para investigar essas estruturas em subsuperficie, auxiliando na avaliação de viabilidade do alvo definido que, para este estudo, foi o Condomínio Villa Verde / Abstract: This work discuss the use of geophysics methods in the study of groundwater in the city of Araçariguama - SP, specifically in the area of Condomínio Residencial Villa Verde that is geologically located over the São Roque granitoid and the shales of Serra do Itaberaba Formation. Because of this geological context, the considered aquifer model is fractured, making important emphasize the descontinuity in the structural characterization of bedrock. There are in the Villa Verde two boreholes, the first one was done during the construction of Villa Verde and the second one was drilled in 2002 when the first borehole could not support the demand for water in Villa Verde anymore. After a geological and geophysical study in the area to determine the best location for the borehole, it was perforated but did not produced water. Considering the problems with water in this area and the exploration difficulties of fractured aquifers, this work seeks the integration of geological and structural studies with dates boreholes in the region where the area is located. The aim is support the interpretation and program of geophysical survey. This study had a practical focus that aimed the definition of potential structures able to have a fractured aquifer. The use here of geophysics as a resource to investigate these structures in the ground intend to be an auxiliary to evaluate the viability of defined target, which for this study were the "Condomínio Villa Verde" / Mestre