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Showing 1 to 20 of 66 for “"seismic velocity"”.
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Seismic velocity and attenuation from full waveform acoustic logs
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1983.
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Towards monitoring volcanoes in Iceland and Hawai’i with seismic velocity variations
Seismic noise interferometry is an exciting technique for studying volcanoes because it provides a continuous measurement of relative seismic velocity (dv/v), which is sensitive to magmatic processes that affect the physical properties of the surrounding crust. However, understanding the causal …
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Monitoring and Imaging Seismic Velocity Changes Across Temporal and Spatial Scales
Relative changes in seismic velocity (dv/v) are associated with changes in mechanical properties of crustal materials, and can reflect the perturbations in stress fields, rock damage, and fluid content. Interferometry of seismic ambient noise enables the continuous monitoring of dv/v. In this …
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Crustal seismic velocity structure of the intermontane and coastal belts, southwestern Canadian Cordillera
One phase of LITHOPROBE's seismic program for the Southern Cordillera included a seismic refraction experiment (SCoRE '89) focussing on the Coast and Intermontane Belts of the Southern Canadian Cordillera. Primary objectives of the refraction program include; i) determining 2-D velocity structure …
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Time-lapse Passive Seismic Velocity Tomography of Longwall Coal Mines: A Comparison of Methods
Time-lapse passive seismic velocity tomography was conducted utilizing data from three underground longwall coal mines to produce a better understanding of the processes that lead to ground failure in mines, especially large, violent failures, such as bumps. Two of the datasets, US Western I and US …
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Quantitative Comparison of Seismic Velocity Tomography With Seismic Activity Around a Deep Coal Longwall Panel
Mining induced seismicity can lead to bumps which cause problems at many mines within the United States and around the world. This seismicity, often referred to as bumps or bursts, can result in injuries, fatalities, and expensive capital damage and production interruptions. There are many factors …
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Modeling of the effects of wave-induced fluid motion on seismic velocity and attenuation in porous rocks
… of the effects of wave-induced fluid motion on seismic velocity and attenuation in porous rocks. In numerical modeling, it is possible to control the factors and inputs that are hard to accomplish in laboratory measurements and isolate those of interest that have significant impact on the …
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SEISMIC VELOCITY, RADIAL ANISOTROPY IN THE CRUST AND UPPER MANTLE OF NORTHEASTERN TIBETAN PLATEAU FROM SURFACE WAVE TOMOGRAPHY
… Plateau using surface wave tomography from teleseismic data recorded at the 36 seismic stations of NorthEast Tibet Seismic (NETS) array. The first part of this dissertation is to construct a 3-D SV velocity (VSV) model using Rayleigh wave data in the NE Tibetan Plateau. The average and 2-D …
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Seismic Velocity and Radial Anisotropy in the Crust and Upper Mantle of the South Central United States from Surface Wave Tomography
… the USArray Transportable Array. 3-D shear-wave velocity and radial anisotropy models were derived from the phase velocities for the Gulf Coast region from Texas to Alabama. In the shallow crust, low velocity appears in the coastal plain to the south of the Ouachita front due to thick sediments. …
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Surface Wave Inversion of the Upper Mantle Velocity Structure in the Ross Sea Region, Western Antarctica
… during Cretaceous to Paleogene rifting. Several seismic studies along the Transantarctic Mountains and Victoria Land Basin’s Terror Rift have shown a general pattern of fast seismic velocities in East Antarctica and slow seismic velocities in West Antarctica. This study focuses on the mantle …
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Seismic Wave Velocity Variations in Deep Hard Rock Underground Mines by Passive Seismic Tomography
… of the rock mass associated with mining-induced seismicity is poorly-understood. Passive seismic tomography is a tool with which the performance of a rock mass can be monitored in a timely manner. Using the tool of passive seismic tomography, the advance rate of operation and mining designs can …
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Ultrasonic velocity measurements of simulated lunar regolith with variable ice content: a laboratory and modeling investigation with implications for geophysical lunar resource exploration
… ice deposit. Geophysical techniques such as seismic methods are routinely used on Earth to extrapolate information from samples over tens of meters to thousands of kilometers and are suitable to do the same for extraterrestrial bodies. This study aims to advance our understanding of how …
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Fluid content effect on acoustic impedance and limits of direct detection capability : illustrated on an offshore prospect
… and oil in some sand formations decreases the seismic velocity and density to such an extent that anomalously large reflections coefficients are encountered at fluid contacts. Geerstma and Gassmann's theories are equivalent and provide a good way to study the physical properties that affect the …
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Continental Tectonics from Dense Array Seismic Imaging: Intraplate Seismicity in Virginia and a Steep Cratonic Margin in Idaho
Dense array seismic techniques can be applied to multiple types of seismic data to understand regional tectonic processes via analysis of crustal velocity structure, imaging reflection surfaces, and calculating high-resolution hypocenter locations. The two regions presented here include an …
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Seismic Imaging of a Granitoid-Greenstone Boundary in the Paleoarchean Pilbara Craton
… bodies. Australian scientists acquired deep seismic reflection data crossing a granitoid-greenstone boundary. Their processing did not image the geologically mapped steep dip of the boundary because standard methods limit the maximum dip. A 37-km section of these data were reprocessed using …
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Velocity Studies in the Deepwater Gulf of Mexico: Keathley Canyon and Walker Ridge Areas
Two different, yet related, velocity studies were undertaken in and around the Keathley Canyon and Walker Ridge areas of the Gulf of Mexico. The first is a compilation of wellbore-salt-body interval velocities (Vint) from 55 wells exhibiting interval compressional-wave velocity variation from …
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Seismic waveform tomography with multicomponent data at a groundwater contamination site
… waveform tomography, to a multicomponent seismic data set acquired over a shallow contaminated aquifer at Hill Air Force Base, Utah. The study combines the high resolution provided by waveform tomography with inherent advantages of SH-wave imaging, such as reduced seismic velocity and …
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Seismic tomographic imaging reveals possible lithospheric erosion beneath Trans-Pecos Texas and Southeastern New Mexico.
… the 1999-2001 La Ristra array revealed a fast seismic velocity anomaly beneath the Rio Grande rift, attributed to a lithospheric "drip" into the mantle, perhaps due to edge-driven convection. To investigate this anomaly, the Seismic Investigation of Edge-Driven Convection Associated with the …
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