Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 31 for “"Hypocenter"”.
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Joint hypocenter-velocity inversion of local earthquake arrival time data in two geothermal regions
Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1991.
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Relocation study of Virginia earthquakes (1959-1981) using the Joint Hypocenter Determination and Joint Epicenter Determination methods
… using a variation (JED/SE77) of the Joint Hypocenter Determination (JHD) method. Joint Epicenter Determinations (JED) were used in conjunction with a companion single event location program (SE77) to relocate hypocenters from data sets in the Giles County seismic zone (GCSZ) in southwestern …
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An Assessment of Hypocenter Errors Associated with the Seismic Monitoring of Induced Hydro-fracturing in Hydrocarbon Reservoirs
… treatments could provide more accurate hypocenter locations and seismic velocities, improving general reservoir characterization. However, for the real, two-well data set obtained for this project, only S-wave picks were available, and testing resulted in anomalous hypocenter location …
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Hypocenter Locations and Focal Mechanism Solutions of Earthquakes in the Epicentral Area of the 1886 Charleston, SC, Earthquake
… was designed to better constrain earthquake hypocenter locations and focal mechanisms. Hypocenter locations of 134 earthquakes indicate a south-striking, west-dipping seismogenic zone in the upper 12 km of the crust. Over 40% of the 66 well-constrained focal mechanisms show reverse faulting …
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Relocation of Eastern Tennessee Earthquakes Using hypoDD
… algorithm is used to calculate accurate relative hypocenter locations by removing the effects of un-modeled velocity structure. The study examines the earthquake hypocenter relocations in an effort to resolve fault orientations and thereby gain insights into the tectonics of the seismic zone. The …
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Local Earthquake Tomography at Mt. Pinatubo, Philippines
… solve separately for both velocity structure and hypocenter locations. Several inversions performed with different initial parameters and convergence schemes, and synthetic checkerboard reconstructions indicate a horizontal spatial resolution of velocity perturbations near 4 km. However, the …
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Geophysical imaging methods for analysis of the Krafla Geothermal Field, NE Iceland
… event locations were determined from the Joint Hypocenter Determination method. Absolute and relative arrival times were used for the two tomographic inversions to jointly invert for event hypocenter locations and velocity structure. Finally, we compared the final velocity structures with a …
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Seismic Source and Attenuation Studies in the Central and Eastern United States
… Mineral, Virginia earthquake. It involves the hypocenter locations of ~3000 earthquakes, ~400 focal mechanism solutions, statistics of the aftershock sequence, and the Coulomb stress modeling that explains the triggering mechnanism of those aftershocks. Second, I examine the S-wave attenuation …
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Determining the focal mechanisms of earthquakes by full waveform modeling
… given an initial estimate of the earthquake's hypocenter, the locations of the seismic recording stations, and the velocity model of the region for a series of depths with intervals of 1 km. Then, we calculate the moment tensor for 6840 different combinations of strikes, dips, and rakes for …
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The New York-Alabama Magnetic Lineament: its reflection character and relationship to the Grenville front
… NYAML and the ETSZ is not clear. More accurate hypocenter locations are necessary to clarify whether the earthquakes are restricted to the region of the crust typified by west dip. If not, the relationship between the earthquakes and the NYAML might be coincidental. A velocity model that …
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Focal mechanisms for eastern Tennessee earthquakes, 1981-1983
… acceptable within pre-set error limits. Hypocenter locations, azimuth and departure angles are taken from locations obtained by the Tennessee Earthquake Information Center (TEIG) with a four layer velocity model (GCOl). A second velocity model (STEP2), developed to improve focal depth …
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Imaging the Soultz Enhanced Geothermal Reservoir using double-difference tomography and microseismic data
… starting event locations obtained using Joint Hypocenter Determination and Collapsing methods. The stimulations produced over 12000 microseismic events of which we chose 8930 for further analysis. We obtained high accuracy cross-correlation differential times and then performed a …
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Analysis and interpretation of clustered microseismicity at geothermal and petroleum reservoirs
… and Injection project demonstrated "real-time" hypocenter modeling for hydraulic fracture diagnostics. The injection produced a hydraulic fracture that exhibited strong spatial asymmetry. Analysis of the results suggest that the phenomenon of "screenout" may be one mechanism contributing to the …
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Fault plane structure of the 1995 Antofagasta Earthquake (Chile) derived from local seismological parameters
… increased significantly the precision of hypocenter determinations. They were distributed mainly on the fault plane itself around the city of Antofagasta and Mejillones Peninsula. The asperity structures were recognized here by the spatial variations of local seismological parameters; at …
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New technologies for unconventional reservoir characterization: Seismic inversion, focal-time estimation, and signal processing to improve reservoir imaging
… enable more accurate positioning of microseismic hypocenters by incorporating seismic reflection data. Signal-processing techniques used in seismic reflection processing are employed in this thesis to enhance the detection quality and quality of induced seismic events. Structural interpretation …
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Continental Tectonics from Dense Array Seismic Imaging: Intraplate Seismicity in Virginia and a Steep Cratonic Margin in Idaho
… surfaces, and calculating high-resolution hypocenter locations. The two regions presented here include an intraplate seismogenic fault zone in Virginia and a steep cratonic margin in eastern Oregon and Idaho. The intraplate seismicity study in Virginia consisted of using 201 short-period …
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Uncertainty Quantification in Earth System Models Using Polynomial Chaos Expansions
… The PC statistical analysis suggests that the hypocenter location plays a dominant role in earthquake ground motion responses (in terms of peak ground velocities, PGVs), while elliptical patch properties only show secondary influence. In addition, Our PC based Bayesian analysis successfully …
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Microseismic observations in the Ceres-Tulbagh aftershock zone, Western Cape, South Africa, and their tectonic implications
… times of these events were used for coupled hypocenter-velocity inversion to produce a one dimensional velocity model with station corrections. The hypocenters of recorded events were relocated using the velocity model and local magnitude was empirically derived for all 168 events. P- and …
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The tectonics and three-dimensional structure of spreading centers--microearthquake studies and tomographic inversions
… of instruments by acoustic ranging, the hypocenter location method, and the treatment of arrival time data are described. Moreover, hypocentral parameters of the 26 largest microearthquakes are reported; 18 of these events have epicenters and focal depths which are resolvable to within ±1 …
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Quantification of ground motions by broadband simulations
… by diminishing directivity effects, while hypocenter location and rupture velocity more strongly influence the variability. The uncertainty in energy magnitude, however, leads to the largest differences of ground motion amplitude between different events, resulting in a variability which is …
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