SEISMIC PROSPECTING

Author: IRIZARRY PADILLA JANIRA.
Year: 2003.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: Aula seminari Dept. D2. Segona planta.
Place of preparation: EDIFICI D2 Campus NORD.

Summary: During this work three principal parts had been developed: a seismic hazard assessment for Catalonia and Barcelona in particular, a vulnerability evaluation of the principal monuments of Barcelona city and the exposure analysis of its urban system. Seismic hazard was evaluated in terms of intensity for the deterministic approach and spectral acceleration for both the deterministic and probabilistic approaches by applying the spectral acceleration attenuation relationship. Site effects were also included. Then seismic hazard maps, acceleration response and demand spectra with soil effects were obtained for the city of Barcelona. The vulnerability assessment for the principal monuments in the city of Barcelona was carried out in two levels. Those monuments with the highest level of protection due to their heritage value (a total of 68 out of over 3000) were analyzed using the vulnerability index method. Then, the vulnerability of a representative monument, the Santa María del Mar church, was evaluated using capacity spectrum method. The capacity curve of the Santa Maria del Mar church was obtained dividing the church in macroelements. The capacity curve was evaluated for the most vulnerable of the macroelements using finite element analysis and equilibrium limit analysis. The expected damages were obtained using the probabilistic and deterministic scenarios in terms of spectral acceleration and then were compared to the historical seismic damage suffered by the church. Finally an urban exposure analysis was carried out for the city of Barcelona based on the available information at the time of this work. The exposure of the following elements was analyzed: residential area, economical activities, commercial activities, industrial activities, tourism activities, hospital services, educational facilities, and some emergency resources. Zones that are critical, important or secondary for the well functioning of these elements at risk were defined within the city. A global exposure analysis was performed for the urban system of the city according to the elements at risk considered. Critical, important and secondary zones were also defined for the well functioning of the city during all the stages of an emergency. Then these results are compared to the expected damages from the probabilistic scenario in order to evaluate the impact of this scenario on the urban system of the city of Barcelona and then identify the areas of the city that would require more attention during the emergency management and the elaboration of seismic action plans.

Author: BONETT DIAZ RICARDO LEON.
Year: 2003.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of preparation: D2 CAMPUS NORD UPC.

Summary: New trends in Earthquake Engineering recognize the need to evaluate the vulnerability of buildings in urban settings. In fact, it is there where the bulk of the world's population, infrastructure and services. Thus, the behavior of the buildings before the occurrence of strong earthquakes, is responsible for avoiding real seismic disasters, such as those to date, still leaving billions in economic losses and an unacceptable number of fatalities. From the foregoing, it appears the motivation of this work has been structured into three major blocs. In the first, have discussed the conceptual and methodological aspects related to the vulnerability assessment and risk seismic buildings in urban settings. In the second part, has been analyzed in detail, comprotamiento seismic expected buildings porticados reinforced concrete located in the city of Manizales (Colombia), characterized by high seismic threat. The development and application of methods and advanced techniques for analyzing the performance vulnerability and fragility of the buildings, has helped establish, in a quantitative manner, the importance, for the minoración earthquake risk, has the design and construction sismo-resistente. The third part is devoted to analysis of seismic risk in the city of Barcelona (Spain), which found in an environment of moderate seismic threat and low, it has not incorporated into their customs and habits constructive, no conscience nor caution seismic, which has resulted in a high vulnerability and fragility of their buildings and therefore a significant risk. The methodologies used in this study were developed from considerations stochastic, which allow to take into account, naturally, uncertainties in the dynamic action in the material and structural features of buildings and consequently, in the results . Various sensitivity analysis has allowed note once again the importance of a correct and tight definition of seismic action, which, if possible, be based on acelerogramas recorded in the study area. The city of Manizales in Colombia, has been one of the scenarios that has resulted in a clear application of the importance of preferring spectra consistent with real actions on other spectra general averaged a wealth of information and finally, might not be representative in any, as is the case even in the response spectra provide streamlined regulations and codes for seismic design. This high sensitivity of the results to the characteristics of the action has also been evident in the other scenario elected Barcelona. Finally, the results show how taking some simple steps seismic protection could reduce up to a degree the damage expected, while the absence of seismic memory, carelessly and abandonment of some minimal precautions, it can increase by grade.

Author: MARTÍNEZ ARÉVALO CARMEN.
Year: 2004.
University: GRANADA [www.ugr.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The objective of this thesis is to study the structure of attenuation in the range of the short period when the volcano Deception Island (Antarctica) and Mount Etna (Italy). The distribution of stations and earthquakes will determine the kind of analysis. So for Deception Island has been estimated the average value of Q factor applying different methods for different types of waves. Thus, for the P waves have been calculated using the Q factor method of spectral decay for frequencies lower than the corner frequency (Qpesp) and the method for the duration of the set (QPpul). The Q factor for the S waves has been estimated by two methods, the method of spectral decay for frequencies lower than the corner frequency (Q esp) and the method of standardization of the coda (Qd). The decay of the coda waves has been estimated by applying the model of the Single Back Scattering (Qc). Based on the values of Q esp Qc, and applying the method of Wennerberg, it has been possible to know Qi and Qs that characterize the contribution of intrinsic attenuation and scattering attenuation to the total. The study conducted attenuation reveals that the structure of the surface area closed bay Fumarolas and 3 km inland from Port pair Foster and a depth less than 2 km is highly atenuativa, varies considerably, with a high degree of fracturing present gas and volcanic or hydrothermal fluids and high temperatures. To study effects of other heterogeneities in the wave fronts, it has investigated the presence of volumes anisótropos. The analysis confirms the existence of anisotropy heterogeneities that might be filled fluid, preferably aligned in the EW direction and WNW-ESE, with a greater concentration in the first 1.4 kilometers. Moreover, the distribution of earthquakes and stations in the volcano. Etna has allowed the determination of a three dimensional structure of wave attenuation P, using the technique of seismic tomography to attenuation and investing the residue factor * t (t *= t / Q). The data used in this analysis are in the seismic crisis occurred in the days prior to the eruption of July-August 2001. The structure 3-D obtained shows the status of eruptive volcano. Anomalies attenuation most notable are: 1-A anomaly high attenuation under the central crater that corresponds to a zone of normal to slightly lower speed of the wave P. Values of P-wave velocity indicates the presence in the area trajectories of magma eruptions earlier. The high attenuation is found due to magma that rose through these channels. The absence of seismicity in this area is due to magma eruption that fueled Central rose by existing pipelines. 2-An anomaly high attenuation south of the central crater. In this area also have found low values of the speed of the P waves of reason vP / vS. The features of this anomaly corresponds to the dam peripheral that fueled the eruption side. The uptrend of this dam deformation occurred, fracturing, seismicity and rising temperatures. 3-An anomaly of low attenuation in the valley of Bove. This anomaly corresponds to a zone of high speed of the P wave of reason vP / vS. Values of P-wave velocity indicate that this anomaly corresponds to a cold magmatic intrusion from other rashes, while the values of vP / vS show that this structure is porous and / or fractured with the presence of gases or volcanic products. A structure of these feature 8 s deberí 6a2 to have high attenuation values. However, the results show low attenuation values. This result can be explained taking into account mechanisms that are triggered in an eruption. The dam peripheral could ascend to lead to increased pressure in the area and / or a release of gas that resulted in a closure or sealing the pores, reducing the attenuation in the area. 4-An anomaly of low attenuation west of the central crater. This anomaly has values of the speed of the P wave of normal to slightly high, and the reason vP / vS slightly low. Therefore, it is a body magmatic from previous eruptions, fractured and fragile areas as shown in the presence of seismicity. It must be emphasized that this is the first time that takes place tomography attenuation of a volcano in a state Eruptive, becoming apparent physical mechanisms that take place during an eruption that are not revealed by tomography speed. It is also important to stress the importance of making tomography attenuation environments volcanic earthquakes that correspond to a single state of the volcano, because in this way you can get the temporal evolution of the volcano, namely its dynamics.

Author: DURÁN GALLEGO RUTH.
Year: 2004.
University: VIGO [www.uvigo.es].
Place of defense: FACULTAD DE CIENCIAS DEL MAR, UNIVERSIDAD DE VIGO.
Place of preparation: FACULTAD DE CIENCIAS DEL MAR, UNIVERSIDAD DE VIGO..

Summary: The application of geophysical techniques (seismic high-resolution side-scan sonar and echo sounding) has helped reconstruct the evolution of sedimentary filling of the Ria de Pontevedra since the Last Glacial Maximum (approx. 18 ka BP), introducing special attention to the current fund . It defines a seismic sequence from the Last Glacial Maximum deposited directly onto the basement of the river and / or unit oldest identified. The basement which is the estuary shows a configuration in blocks determined by three systems of fractures (NS NE-SO and NNE-SSO). In the depressions of the basement this unit is deposited old age Pleistocena. The roof of these sediments is trucando by a surface highly erosive, incised channel presence, which represents exposure subaérea across the river during the fall of the sea level at the Last Glacial Maximum. On this surface develops a sequence of 5 Order consists of a Courting Sedimentario Transgresivo, in turn formed by a set of units retrogradantes and Courting Sedimentario High Level. The curve of variation in sea level relative obtained from the analysis sísmico-secuencial shows a transgression of pulses interrupted by small stabilization and cooling sea level. Finally, the map morfosedimentario fund's current reflects the importance of structural recent sedimentation in the estuary. Fields sedimientos thick sedimentary forms of transport load fund are located in areas of greatest influence in waves.

Author: Jiménez Lloret Abigail.
Year: 2005.
University: ALMERÍA [www.ual.es].
Place of defense: D.de Física Aplicada.
Place of preparation: Departamento de Física Aplicada.

Summary: It introduces the problem of seismicity from a broad viewpoint, the complex systems, which is so important to describe the individual processes as global processes or interaction. Wanted defining pattern and seismic modeling of the evolution of the pattern over time. It means a pattern emerging property or any regularity in the system, which can be used to reduce the evolution of complex system with a problem of low dimensionality effective, and therefore, a more manageable. The model of evolution implemented using a standard definition of seismic data location and magnitude, which could be expanded definition data attenuation factor and the source parameters in the future. In chapter 3 we calculated attenuation from waves coda at the station Adra (Almeria), also developed and used with data belonging to the basin of Grenada, a technique for the simultaneous achievement of the attenuation factor and parameters and spectral source, based on Genetic Algorithms (Jimenez et al., 2005). The methodological bases for addressing the evolution of seismic patterns are well established in Chapter 4. You can idealize the seismicity as a series of discrete patterns in three ways, the spatial, temporal and energy through a process of mesh. This representation allows the use of the Theory of PLCs for modeling and facilitates obtaining a function of changing them using the concepts of Information Theory. The method of analysis of changes in the patterns of seismic proposed in this Doctoral Thesis provides maps of Probabilistic Seismic Endangerment (GIPA) for each energy level (scale) considered. Information Mutual represents the expected value of the gain information to make a distribution of past and present statements dependent rather than make a distribution of independent states. At maximizarla is obtained, then, the maximum dependency between past and future states. The discretization of the problem can be evaluated easily makes the mistakes of the model by Hamming distance. This methodology was applied to a catalog of earthquakes that occurred in the Iberian Peninsula from 1970 to 2001 (provided by IGN), another for Béticas between 1985 and 1999 (IAG), a catalog for region Pirenáico-Catalana from 1970 to 2001 (CBI ) and another for the area of the Gulf of Cadiz (IGN), giving Maps Probabilistic Seismic Endangerment, GIPA, for each of these regions. In chapter 5 adopted a viewpoint mecano-estadístico for describing the evolution of seismic patterns. The analysis Karhunen-Loève (Tiampo, 2000) was used in the catalog seismic used to the Iberian Peninsula. Each of these patterns represents, in order of importance, the various interactions found in the system. The calculation of the parameters of the law Gutenberg-Richter from its experimental probability function provides a better assessment of the magnitude of court from which this law is met. There are physical basis for proposing a especie-área, similar to that known in Ecology, among registered magnitudes and the area analyzed. You can use the formalism of Statistical Mechanics to study the seismicity. The approximate field average (index IP) is useful for the evaluation of the seismic hazard in a region. The discrete seismic patterns can be described by an Ising model. That 8 model t 6b4 ambién used with success in obtaining maps of Probabilistic Seismic Endangerment, and the rules of transition following best describes the seismicity that the models obtained in chapter 4. The gain is greater information, especially large quantities, more useful for the prevention of seismic disasters, the same way as the Hamming distance average (error) decreases. The index is equivalent to IP Ising model proposed when using the same approach to the activity of cells, as well as the same cell sizes and temporal intervals. The use of criteria for activating the cells based on the number of earthquakes is based on the persistence found in the signals, with Hurst exponent close to 1. It prefers the Ising model (for the slippage of the fault, whose behavior is persistent, with Hurst exponent of greater than 0.5), because it sets a threshold magnitude of activity and determine a specific time of validity of the map. The rules describe a transition from paramagnetic behavior.

Author: RUEDA NÚÑEZ JUAN JOSÉ.
Year: 2005.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS AGRÓNOMOS.

Summary: This thesis deals with discrimination seismic remote region. This study processes that relate to the source and spread of different explosions and earthquakes using data from the device of Donseca and Seismic Network of broadband National Geographic Institute. The goal is discrimination of large explosions such as nuclear, but also chemical explosions lesser magnitude that occur daily and that its misclassification leads to pollution of seismic catalog.

Author: MANCILLA PEREZ FLOR DE LIS.
Year: 2005.
University: GRANADA [www.ugr.es].
Place of defense: Facultad de Ciencias.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This work is a contribution to knowledge of the characteristics of propagation of seismic waves in the south of the Iberian Peninsula and Alboran Sea, within the frequency range of interest to the seismic hazard. They have looked at all the digital seismograms from the year 1999 until the year 2005 recorded by the seismic stations, both in the short term as broadband, belonging to the Andalusian Institute of Geophysics. These stations are deployed in southern Spain. With these tests have been able to characterize the properties atenuativas of the study area and have obtained average measures that allow us to quantify and predict the movement of seismic ground is expected in this area in terms of the magnitude of the earthquake and distance to his hipocentro. These laws empirical regional climbed the movement of soil are an average of the characteristics of the medium in which the waves propagate from the source to the recipient of the seismic sources occurring in the study area and the site where record waves. In this work we have obtained the scaling laws of the spectral amplitude RMS and peak amplitude depending on the size of the earthquake and distance for eight narrow bands of frequency, focusing in [1, 2, 3, 4, 6, 8, 10 and 12] Hz. This has been done through a recursive least squares regression of the observations of spectral amplitudes RMS and peak amplitudes. Moreover, in these frequency bands, have been measured durations of the window more energy sismograma and have obtained some functions average duration with the distance. Due to the nature and configuration of the seismic networks used in this work and heterogeneity of the study area in which propagate seismic signals are grouped and analyzed individually different datasets. This has highlighted the differences in the characteristics atenuativas from the bark of Alboran Sea and the Béticas. In addition to obtaining empirical these laws have shown that the theory of random vibration (RVT) works, allowing reproduce the most important features of the movement of soil in the time domain using the spectral amplitude and duration of the RMS movement.

Author: GARCÍA JIMÉNEZ DANIEL.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS FÍSICA - UNIVERSIDAD COMPLUTENSE DE MADRID.
Place of preparation: FACULTAD DE CIENCIAS FÍSICAS, UNIV. COMPLUTENSE DE MADRID.

Summary: The Pacific coast of Mexico is in a margin of subduction in the seismic hazard is associated basically two types of earthquakes: interplaca, generated by low-angle reverse faults near the coast (H 10-30 km) and intraslab, which take place in the interior dela plate subduction, in favor of normal faults at a certain depth (H 40-150 km). Both types of earthquake historically have generated great human and material damage in the area. The improvement in the local and regional seismic networks has allowed in the last twenty years collecting large amount of strong motion records for both kinds of earthquake. These endeavors have made major advances in understanding the movement caused by the seismicity interplaca, and has begun studying the less frequent seismicity intraslab. This thesis is intended to cover two main objectives: 1, - complete some of the gaps in current knowledge of earthquakes interplaca. 2, - study intensely in the understanding of the movement of soil generated by earthquakes intraslab. To achieve these goals has been used an extensive database of strong movement covering the last twenty years (1985-2005) and significantly improve the foundations employed so far. This collection has been supplemented by a detailed review dela literature and the relocation of a portion of the earthquakes. These data have led on the one hand, to characterize the functions of attenuation of both kinds of earthquakes, as well as propose an empirical model for the Fourier spectrum of the source of earthquakes intraslab. The results suggest that these events show a drop efforts significantly higher than that of interplaca, which explains the higher movements observed in the epicentral area for the former. They have also shown that the relaxation of the movement for earthquakes interplaca is greater for paths along the coast into the interior of the continent, due to the marked heterogeneity in the cortical structure. For earthquakes intraslaba Instead, the decay with distance from the movement seems to be simpler and more rapid than those interplaca. Moreover were determined equations of motion for estimating strong movement expected for both types of earthquake. The equations have been developed for the spectrum of response pseudoaceleración (PSA), the peak acceleration (PGA) and the maximum speed (LG) and the maximum speed (LG). These results suggest that the movement in the epicentral area of an earthquake intraslab large exceeds that of a interplaca, especially at high frequencies. By contrast, under increasing distance from the source movement for a interplaca exceeds progressively a intraslab, mainly intermediate frequencies, which for the first will be expected damage to buildings for greater distances and higher note. These results show a reasonable agreement with those by other authors for several subduction zones in the world.

Author: GUINTO HERRERA ESTEBAN ROGELIO.
Year: 2005.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of preparation: EDIFICI D2 205 CAMPUS NORD.

Summary: This study was based on the coefficients of attenuation anelástica experimental mode fundamental Rayleigh waves obtained by applying the method of the two stations for a large number of trains waves, in order to obtain tomography images of the structure anelástica of the basin of the Mediterranean Sea. The study is a continuation of work done by Martinez (1998) and Martinez et al. (200), with respect to the classical structure, so we tried to keep a notation and mathematical formulation which is as close as possible were used data provided by IRIS (Incoporated Research Institutions for Seismology), networks Geofon, Geoscope, IRIS / USG and MedNet, with data to be recorded 24 stations VBB, located in countries of the Mediterranean area the 225 events seismic considered for the period 1990-2002. We have analyzed more than 3000 signs, which delas to avoid inconsistencies in the results and due to a signal / noise insufficient, or failures delos calibration sensors among others, it was decided to use a quarter of them around. With all this, it was possible to have averaged attenuation coefficients for 124 trajectories. The spatial coverage reached with these trajectories is good enough for much of the region under study. At more than 3000 signs, techniques have been applied conventional filtering and were determined coefficients of attenuation anelástica using the method of the two stations density of coverage has advised comprehensive treatment of this information by applying the method Yanovskaya- Ditmar, to obtain local values for coefficients attenuation anelástica According to our region of interest, has been considered a horizontal mesh with a density of 1Â ° longitude by 1Â ° latitude. At each point on the mesh, in-depth, we applied a method investment stochastic (R Software. B. Hermann, Saint. Louis University, 1991), local values for attenuation to obtain models 1-D bearings internal shear waves (Qbeta1). Interpolation of these models allows us to obtain a model 3-D. An analysis of the various results comparing the eastern Mediterranean to the western Mediterranean at depths of 35 to 80 km (lithosphere), highlights some important structural differences. The western Mediterranean presents the greatest values of internal friction coefficients, concentrating them in the area between the blockade Córcega-Cedeña and the Italian peninsula. The high attenuation in that area should be the result of the thinning of their bark and gracious presence of material at the higher levels asthenospheric mantle. For greater depths, the attenuation can be presented in a strip a tan6to uneven stretching from the eastern Mediterranean to northern Italy. It can also be inferred from our results, which has a thinner crust in the western Mediterranean which is consistent with previous studies. The memory of watching thesis is structured in three blocks: The first block (Introduction) is introductory in nature and contains three chapters: 1-Introduction 2-Features seismotectonic 3-elastic structure. The second block (Methodology) provides the tools necessary for the processing of the data from this work and includes two chapters: 4, - Selection of seismograms 5, Methods and techniques of data analysis. The third and final block (Structure enelástica the basin of the Mediterranean Sea) deals with regard to the determination of the structure anelástica in our region of interest and contains four chapters 6-selection data for the study, 7-attenuation coefficients anelástica and coefficients of friction internal 8-tomography images of the internal friction.

Author: CARCOLÉ CARRUBÉ EDUARDO.
Year: 2005.
University: RAMÓN LLULL [www.url.edu].
Place of defense: INSTITUTO UNIVERSITARIO OBSERVATORIO DEL EBRO.
Place of preparation: INSTITUTO UNIVERSITARIO OBSERVATORIO DEL EBRO.

Author: TAPIA JIMENEZ MARIA DEL MAR.
Year: 2006.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: AULA 212, EDIFICI D2.
Place of preparation: EDIFICI D2 205 Campus NORD.