Elastic anisotropy is present where the speed of a seismic wave depends on its direction. In Earth's mantle, elastic anisotropy is induced by minerals that are preferentially oriented in a directional flow or deformation. Earthquakes generate two seismic wave types: compressional (P) and shear (S) waves, whose coupling in anisotropic rocks leads to scattering, birefringence, and waves with hybr...

The recent evolution of induced seismicity in Central United States calls for exhaustive catalogs to improve seismic hazard assessment. Over the last decades, the volume of seismic data has increased exponentially, creating a need for efficient algorithms to reliably detect and locate earthquakes. Today's most elaborate methods scan through the plethora of continuous seismic records, searching ...

Measurements of the transmission of seismic survey signals in Australian waters are presented. The measured transmission loss showed: high variability of received signal sound exposure level at similar ranges when comparing all surveys (mean of standard deviation across ranges of 3-12 dB); high variability within a seismic survey (mean of standard deviation at any range of 2-4 dB); typical shot...

Thirteen seismic profiles totaling 242 km were reprocessed in the Mackenzie Delta area in order to map the shallow gas hydrated deposits and to map detail structure around the proposed drill site for the gas hydrate research program. Seismic data were acquired for conventional oil exploration purposes in this area in the middle of 1980, so the field parameters were not optimum for the shallow s...

1 T a b l e o f C o n t e n t s Abstract i i Acknowledgments viii Problem and Thesis Objective I Review of Previous Work 2 Multi-Criteria Optimal Design 2 Reliability-Based Design Earthquake Identification 6 A Time Variant Approach to Performance-Based Engineering 9 Seismic Performance Evaluation For Steel Moment Frames 10 Optimal Probabilistic Seismic Demand Models For Typical Highway Overpass...

D analyses of structures responding elastically to ground motions recorded during severe earthquakes have shown that the theoretical response inertia loads are generally significantly greater than the static design lateral loads recommended by codes. Hence, structures designed for the lateral earthquake loads recommended by codes can only survive severe earthquakes if they have sufficient ducti...

Seismic interferometry processing is applied to an active seismic survey collected on ocean bottom seismometers (OBS) deployed at 900-m water depth over a carbonate/ hydrates mound in the Gulf of Mexico. Common midpoint processing and stacking of the extracted Green’s function gives the subsurface PP reflectivity, with a horizontal resolution of half the receiver spacing. The obtained seismic s...

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Setting, planning, and goals. . . . . . . . . . . . . . . 1 Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Results and discussion. . . . . . . . . . . . . . . . . . . . 7 Summary and conclusions. . . . . . . . . . . . . . . . 15 Acknowledgments. . . . . . . . . . . . . . . . . . . . . . 16 References . . . . . ...

This paper compares three unsupervised projection methods: Principal Component Analysis (PCA), which is linear, Self-Organizing Map (SOM) and Curvilinear Component Analysis (CCA), which are both nonlinear. Performance comparison of the three methods is made on a set of seismic data recorded on Stromboli that includes three classes of signals: explosion-quakes, landslides, and microtremors. The ...

Relating sedimentary records to seismic data is a major challenge. By shifting focus to a scale-invariant sharpness characterization for the reflectors, we develop an attribute that can capture and categorize the main reflector features, without being sensitive to amplitudes. Sharpness is defined by a scale exponent, which expresses singularity order and determines the reflection signature/wave...