Seismic traveltime inversion, traveltime tomography and seismic reflection techniques have been applied for two dimensional (2D) and three dimensional (3D) data acquired in conjunction with site characterization and monitoring aspects at a carbon dioxide (CO2) geological storage site at Ketzin, Germany (the CO2SINK project). Conventional seismic methods that focused on investigating the CO2 storage and caprock formations showed a poor or no image of the upper 150 m. In order to fill this information gap, an effort on imaging the shallow subsurface at a potentially risky area at the site is the principal goal of this thesis. Beside this objective, a seismic source comparison from a 2D pilot study for acquisition parameter testing at the site found a weight drop source suitable with respect to the signal penetration, frequency content of the data and minimizing time and cost for 3D data acquisition. For the Ketzin seismic data, the ability to obtain high-quality images is limited by the acquisition geometry, source-generated noise and time shifts due to near-surface effects producing severe distortions in the data. Moreover, these time shifts are comparable to the dominant periods of the reflections and to the size of structures to be imaged. Therefore, a combination of seismic refraction and state-of-the-art processing techniques, including careful static corrections and more accurate velocity analysis, resulted in key improvements of the images and allowed new information to be extracted. The results from these studies together with borehole information, hydrogeologic models and seismic modeling have been combined into an integrated interpretation. The boundary between the Quaternary and Tertiary unit has been mapped. The internal structure of the Quaternary sediments is likely to be complicated due to the shallow aquifer/aquitard complex, whereas the heterogeneity in the Tertiary unit is due to rock alteration associated with fault zones. Some of the major faults appear to project into the Tertiary unit. These findings are important for understanding the potentially risky anticline crest and can be used as a database for the future monitoring program at the site.

Multiple geophysical and geological data sets were compiled, reprocessed, and interpreted using state-of-the-art signal processing and modeling algorithms to characterize the complex post-Paleozoic geology that overlies the southwestern projection of the Fluorspar Area Fault Complex (FAFC) in western Kentucky. Specific data included 21.5 km of SH-wave seismic reflection, 1.5 km of P-wave seismic reflection, 2 km of electrical resistivity, vertical seismic profiles, Vp and Vs sonic-suspension logs, and 930 lithologic borehole logs. The resultant model indicates three general northeast–southwest-oriented fault zones pass through the study area as southwestern extensions of parts of the FAFC. These fault zones form two significant subparallel grabens with ancillary substructures. The geometry of the interpreted fault zones indicates that they have undergone episodic tectonic deformation since their first formation. Evidence of thickening and steeply dipping reflectors within Tertiary and Quaternary sediment in the downthrown blocks indicate syndepositional movement. Subtle thickening and lack of steeply dipping intraformational reflectors in the Cretaceous suggest a more quiescent period, with sediment deposition unconformably draping and filling the earlier Paleozoic structural surface. There is also evidence that the Tertiary and early Quaternary reactivation was associated with an extensional to compressional regional stress reversal, as manifested by the antiformal folds seen in the hanging wall reflectors and the potential small-amplitude force folds in the Quaternary alluvium, as well as a clear displacement inversion along the Metropolis-loess seismic horizon in two high-resolution reflection images. A surface shear-wave splitting experiment proved to be an efficient and effective tool for characterizing shallow subsurface azimuthally anisotropic geologic inclusions in low-impedance water-saturated sediment environments. The measured azimuthal anisotropy across a well-constrained N60ºE-striking fault exhibited a natural coordinate system that had a fast direction coincident with the fault strike and an orthogonal slow direction. This is also one indicator that faults inactive during significant geologic intervals (i.e., Holocene) do not "heal". Integrated shear-wave velocity models and electrical resistivity tomography profiles across the fault zones exhibit lower shear-wave velocities and resistivities within the deformation zones compared with values outside the boundaries. This is additional evidence that the deformed sediment does not reconsolidate or heal, but that the sediment particle configuration remains more loosely packed, providing an increase in the overall porosity (i.e., hydraulic conductivity). This can wholly or in large part explain the anomalous contaminant plume migration path that is coincident with the deformed zones of the regional gravel groundwater aquifer.

<p>Seismic traveltime inversion, traveltime tomography and seismic reflection techniques have been applied for two dimensional (2D) and three dimensional (3D) data acquired in conjunction with site characterization and monitoring aspects at a carbon dioxide (CO₂) geological storage site at Ketzin, Germany (the CO₂SINK project). Conventional seismic methods that focused on investigating the CO₂ storage and caprock formations showed a poor or no image of the upper 150 m. In order to fill this information gap, an effort on imaging the shallow subsurface at a potentially risky area at the site is the principal goal of this thesis.</p><p>Beside this objective, a seismic source comparison from a 2D pilot study for acquisition parameter testing at the site found a weight drop source suitable with respect to the signal penetration, frequency content of the data and minimizing time and cost for 3D data acquisition.</p><p>For the Ketzin seismic data, the ability to obtain high-quality images is limited by the acquisition geometry, source-generated noise and time shifts due to near-surface effects producing severe distortions in the data. Moreover, these time shifts are comparable to the dominant periods of the reflections and to the size of structures to be imaged. Therefore, a combination of seismic refraction and state-of-the-art processing techniques, including careful static corrections and more accurate velocity analysis, resulted in key improvements of the images and allowed new information to be extracted. The results from these studies together with borehole information, hydrogeologic models and seismic modeling have been combined into an integrated interpretation. The boundary between the Quaternary and Tertiary unit has been mapped. The internal structure of the Quaternary sediments is likely to be complicated due to the shallow aquifer/aquitard complex, whereas the heterogeneity in the Tertiary unit is due to rock alteration associated with fault zones. Some of the major faults appear to project into the Tertiary unit. These findings are important for understanding the potentially risky anticline crest and can be used as a database for the future monitoring program at the site.</p>

Approved for public release, distribution is unlimited / Landmines continue to be a threat to both military and civilian communities throughout the world. Current methods of detection, while better than nothing, could certainly be improved. Seismic SONAR is a promising new technology that may help save countless lives. The goal of this thesis was to advance Seismic SONAR development by introducing a mobile source which could be easily used in practical applications. A small tracked vehicle with dual inertial mass shakers mounted on top was used for a source. The source accurately transmitted the shaker signal into the ground, and its mobility made it a practical choice for field operations. It excited Rayleigh waves, as desired, but also generated undesirable P-waves and was not found to be directional. It proved incapable of finding a target. Improvements, such as a deploying an array of mobile sources and a stronger source, should vastly enhance the performance of such tracked vehicles in seismic SONAR mine detection and should be pursued. / Ensign, United States Navy

Visando estudo do método de sísmica multicomponente (3C) na investigação rasa, foram adquiridos dados em duas áreas urbanas da cidade de São Paulo, Brasil, com características geológicas diferentes: Campus da Universidade de São Paulo (USP), situado na zona oeste do município e área da estrutura de Colônia, situada na região de Parelheiros, na zona periférica do município. Na aquisição foram empregados geofones de 3 componentes com frequência natural de 10 Hz e, como fontes sísmicas, o compactador e o impacto de uma marreta. Para realizar o processamento dos dados foi utilizado o pacote Seismic Unix (CWP/SU). Foi observada uma marcada diferença nas respostas dos subsolos entre os dois sítios. Nos dados adquiridos no Campus da USP foram observadas tanto as ondas PP como as ondas convertidas (PSv), no entanto, nos dados obtidos em área de Colônia, não foi possível visualizar as ondas convertidas. A partir das secções da onda PP e da onda PS foi estimada a razão Vp/Vs assim como o coeficiente de Poisson para a área da USP. / In order to study the multicomponent seismic method (3C) to shallow investigation, two data sets were acquired in urban areas of São Paulo city, Brazil, with different geological characteristics. The area of the Campus of São Paulo University (USP) is located in the western part of the city and the area of the structure of Colônia is located in the region of Parelheiros, a peripheral zone of São Paulo. For the data acquisition, it were employed 3C-geophones of 10 Hz and, as seismic sources, hand-operated surface compactor and sledge hammer. For processing were used the Seismic Unix package (CWP / SU). It was observed a marked difference in the subsoil responses between the two sites. In the data acquired in the Campus of USP, both PP waves and converted waves (PSv) was observed; however, in the data obtainedin the Colônia area, it was not possible to visualize the converted waves. For the USP area, the Vp / Vs ratio and Poisson ratio were estimated.

Visando estudo do método de sísmica multicomponente (3C) na investigação rasa, foram adquiridos dados em duas áreas urbanas da cidade de São Paulo, Brasil, com características geológicas diferentes: Campus da Universidade de São Paulo (USP), situado na zona oeste do município e área da estrutura de Colônia, situada na região de Parelheiros, na zona periférica do município. Na aquisição foram empregados geofones de 3 componentes com frequência natural de 10 Hz e, como fontes sísmicas, o compactador e o impacto de uma marreta. Para realizar o processamento dos dados foi utilizado o pacote Seismic Unix (CWP/SU). Foi observada uma marcada diferença nas respostas dos subsolos entre os dois sítios. Nos dados adquiridos no Campus da USP foram observadas tanto as ondas PP como as ondas convertidas (PSv), no entanto, nos dados obtidos em área de Colônia, não foi possível visualizar as ondas convertidas. A partir das secções da onda PP e da onda PS foi estimada a razão Vp/Vs assim como o coeficiente de Poisson para a área da USP. / In order to study the multicomponent seismic method (3C) to shallow investigation, two data sets were acquired in urban areas of São Paulo city, Brazil, with different geological characteristics. The area of the Campus of São Paulo University (USP) is located in the western part of the city and the area of the structure of Colônia is located in the region of Parelheiros, a peripheral zone of São Paulo. For the data acquisition, it were employed 3C-geophones of 10 Hz and, as seismic sources, hand-operated surface compactor and sledge hammer. For processing were used the Seismic Unix package (CWP / SU). It was observed a marked difference in the subsoil responses between the two sites. In the data acquired in the Campus of USP, both PP waves and converted waves (PSv) was observed; however, in the data obtainedin the Colônia area, it was not possible to visualize the converted waves. For the USP area, the Vp / Vs ratio and Poisson ratio were estimated.

Conventionally, to speed up scientific or engineering (S&E) computation programs on general-purpose computers, one may elect to use faster CPUs, more memory, systems with more efficient (though complicated) architecture, better software compilers, or even coding with assembly languages. With the emergence of Field Programmable Gate Array (FPGA) based Reconfigurable Computing (RC) technology, numerical scientists and engineers now have another option using FPGA devices as core components to address their computational problems. The hardware-programmable, low-cost, but powerful “FPGA-enhanced computer” has now become an attractive approach for many S&E applications. A new computer architecture model for FPGA-enhanced computer systems and its detailed hardware implementation are proposed for accelerating the solutions of computationally demanding and data intensive numerical PDE problems. New FPGAoptimized algorithms/methods for rapid executions of representative numerical methods such as Finite Difference Methods (FDM) and Finite Element Methods (FEM) are designed, analyzed, and implemented on it. Linear wave equations based on seismic data processing applications are adopted as the targeting PDE problems to demonstrate the effectiveness of this new computer model. Their sustained computational performances are compared with pure software programs operating on commodity CPUbased general-purpose computers. Quantitative analysis is performed from a hierarchical set of aspects as customized/extraordinary computer arithmetic or function units, compact but flexible system architecture and memory hierarchy, and hardwareoptimized numerical algorithms or methods that may be inappropriate for conventional general-purpose computers. The preferable property of in-system hardware reconfigurability of the new system is emphasized aiming at effectively accelerating the execution of complex multi-stage numerical applications. Methodologies for accelerating the targeting PDE problems as well as other numerical PDE problems, such as heat equations and Laplace equations utilizing programmable hardware resources are concluded, which imply the broad usage of the proposed FPGA-enhanced computers.

Thesis (Doctoral)--Universität Karlsruhe, 2000. / Abstract in German. Includes bibliographical references (p. 107-111). Also available via the World Wide Web. Also available via the World Wide Web. http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=2000/physik/1 http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=/2000/physik/2

Thesis (Doctoral)--Universität Karlsruhe, 2000. / Hochschulschrift = Thèse/Mémoire. Also available via the World Wide Web. http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=2001/physik/2

Thesis (Doctoral)--Universität Karlsruhe, 2000. / Abstract in German. Hochschulschrift = Thèse/Mémoire. Also available via the World Wide Web. http://www.ubka.uni-karlsruhe.de/cgi-bin/psview?document=2001/physik/2