GEOPHYSICS

Author: NUÑEZ AGUILAR JUAN IGNACIO.
Year: 2004.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.

Summary: With this Doctoral Thesis opens a new line of research in Spain: arqueomagnetismo. This is based on the study of magnetism termorremanente in archaeological materials to investigate the Secular Variation in declination and inclination of the Earth Magnetic Field in historical period. The main objective of the work is thus creating a first curve Secular Variation of the past millenniums to the Peninsula and referring to Madrid. To achieve this goal have been investigated 25 structures (furnaces, hot springs and buildings burned) from archaeological sites on the Peninsula with chronologies between Century 1 BC The sixteenth century AD On the other hand there has been a data collection, imposing certain quality criteria, previous studies of southern France and northern Morocco in the region where you can still considered valid approximate Dipolar field Geomagnético. Also included are the results of the only three work in our country. In total we have obtained 84 data for obtaining the curve. For the most recent period, have also added data from the measures instrumentation is available from the mid-nineteenth century on the Peninsula. In addition to the contributions to the field of Geophysics this work lays the groundwork for the introduction of a new dating technique of archaeological sites on the Peninsula. This technique is being used for more than a decade in neighboring countries such as France or Britain which have curves Secular Variation, revised several times, for years.

Author: CESCA SIMONE.
Year: 2004.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS FISICAS.
Place of preparation: FACULTAD DE CIENCIAS FISICAS , UCM.

Summary: The aim of the thesis is to obtain the moment tensor for earthquakes surface (H MORE 40KM) from rigistros seismic broadband regional distances (* greater 400km). Resolving the issue directly has been divided into two stages: generation delas functions green and convolution of the tensor components withthe moment sísmico.La inversion of seismic moment tensor is performed by adjusting the amplitude spectra, from the records relating to the airwaves internas.La application of the method in cases theoretical reveals the characteristic features of green and displacement theory, the variasr some parameters delmodelo, and study the stability of the investment by introducing errors in the model used (stratification of the earth model, depth of focus and length the function of time). Comparing the investment in time and frequency domain shows the mayro stability is the second técnica.Posteriormente applies the method developed TO 4 earthquakes in Spain, with different characteristics, using records of seismic stations broadband Spain in each study determines the focal mechanism for different focal depths as great a mechanism and a pair of dual component compensated linear vector dipole obtained together is the seismic moment tensor qu the profundida of fuente.Los results are compared with solutions obtained with other methods of investment and with the polarities observadas.La application to earthquakes observed reveals and interpretgar identifying solutions ambiguous, and relate it to imprecision in the definition of the model tierra.El method developed is complemented by the description of a methodology for the generation and use of database functions green, which makes it possible to reduce the time of calculation.

Author: ARANGO GALVÁN CLAUDIA.
Year: 2004.
University: BARCELONA.
Place of defense: FACULTAD DE GEOLOGÍA.
Place of preparation: FACULTAD DE GEOLOGÍA.

Summary: To the south of the town of Llucmajor (Mallorca) appear some evidence of local spas, expressed as a temperature anómalamente high water extracted in some wells. The method audiomagnetotelúrico (AMT) has proved to be a suitable technique and increasing interest someros to conduct geological and hydrogeological studies (eg Hautot et al., 2002) and especially in geothermal problems. Its use has increased in the last fifteen years as a result of improved instrumentation and processing. However this technique presents a difficulty inherent in exploration mangetotelúricas a cursory: the signal used as a natural source shows a minimum around the high frequencies. This thesis focuses on two aspects of the method audiomagnetotelúrico: a methodology where we propose a new scheme processing that responds to the problem of gang dead and another applied to obtain the structure geoeléctrica 3D corresponding to the area of Llucmajor (Majorca). The first goal is to develop an algorithm for data processing magnetotelúricos based on Transformed Ondicular (wavelet transform). The technique is based on the ability of this transformed to decompose the signal into its contributions both in the spectral domain as in the storm, which facilitates the detection of those segments in which the temporary signal has a greater extent. Finally, to evaluate the effectiveness of the method, provides a comparison with the basic outline of estimating tensor impedances. The objective pursued is the development of a model geoeléctrico dimensional from an area south of the town of Llucmajor to characterize the aquifer that provides the geothermal anomaly. In building the model has been used as answers magnetotelúricas curves apparent resistivity and decisive phase of the tensor impedances. In short, this thesis deals with two innovative aspects of the interpretation magneotelúrica. On one side is the improvement in the processing of data magnetotelúricos and on the other, three-dimensional modeling and interpretation.

Author: RUIZ PÉREZ JAVIER.
Year: 2005.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS GEOLÓGICAS.
Place of preparation: FACULTAD DE CIENCIAS GEOLÓGICAS.

Summary: The investigation of the dynamics of the lithosphere of the planets and satellites in the solar system is itself the highest interest, but also brings a new perspective to our understanding of the forces acting on the Earth itself. In this thesis is the study of the thermal state of the lithosphere and the satellites of Mars' ice outer Solar System, its relations with the mechanical structure of the lithosphere, and the application of methods developed to the study of lithosphere of the earth. The results for the case of Mars suggests strongly that his bark is differentiated can make out a top layer, rich in radioactive elements producing heat, a lower crust, with little heat sources, a result consistent with results based on some arguments geochemical. Moreover, the study of the relatively low distortion of an ancient coastlines suggests the lithosphere of Mars has not experienced global events for at least three billion years. The study of Europe, satellite of Jupiter, has provided clear evidence that most of the dissipated thermal flux by warming tidal originates in a layer relatively warm and active convection, located toward the bottom of the crust of ice. The total thickness of the crust must be between 15 and 50 km. The 2-6km above correspond to a layer and cold convectivamente immobile, which it can be considered roughly equivalent to the mechanical lithosphere and the rest of the crust is actively involved dela convection. The presence of internal oceans can be a common phenomenon in satellites and icy worlds in the solar system outside, which would be a natural consequence of the physical properties of ice water, until now treated in an overly simple manner, which would result in greater resistance cooling, thereby preventing their freezing. Finally, the application of the methodology developed in this allows the Earth to discuss issues such as the upper mantle rheology of their contribution to the total resistance of the lithosphere. Thus, one of the most important results achieved with the realization of this thesis is that the investigation of other planetary bodies, develops simultaneously with the Earth, it can provide a much broader vision of the concept of the lithosphere.