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.
Results
Showing 1 to 19 of 19 for “"seismic attenuation"”.
-
AN INVESTIGATION OF SEISMIC ATTENUATION IN MARINE SEDIMENTS
… have been relatively few investigations into the attenuation properties of unconsolidated sediments using marine surface seismic data. Several methods of measuring attenuation were assessed for reliability in a noise-free case and with the addition of noise using a set of synthetically absorbed …
-
The seismic attenuation structure of the East Pacific Rise
Studies of seismic propagation through oceanic crust have contributed enormously to our understanding of the generation and evolution of oceanic crust However, such work has largely been confined to the seismic velocity structure. In this thesis we present results from a study of seismic …
-
The seismic attenuation structure of the East Pacific Rise
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1992.
-
Determination of seismic attenuation using observed phase shift in sedimentary rocks
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1982.
-
Constraining the Radial Structure of Seismic Attenuation using Multiple S-Wave Datasets
Seismic attenuation, quantified by the quality factor Q, provides crucial constraints on Earth's thermal and chemical structure due to its strong sensitivity to temperature and presence of volatiles. This study investigates the radial Q structure of Earth's mantle using amplitude measurements from …
-
Seismic attenuation of regional phases in the northern Middle East and the Tibetan Plateau
… AT AUTHOR'S REQUEST.] I study the regional seismic phase attenuation to (1) infer rheology and temperature of the crust and uppermost mantle and to (2) develop reliable and transportable nuclear discriminants. The methods used in my research have advantages over other methods by eliminating …
-
A Study of Mine-Related Seismicity in a Deep Longwall Coal Mine
This study involves seismic monitoring of a deep coal mine. The purpose is to examine the processes responsible for induced seismicity. A seismic network consisting of five three-component short-period seismometers located above the mine recorded the seismic data. The events discussed here occurred …
-
Seismic Tomography at Volcanic Rift Zones and Transpressional Plate Boundaries Askja Caldera and Macquarie Island
… thesis consists of two main parts: imaging the seismic structure beneath Askja caldera, Iceland, located in a divergent tectonic setting, and Macquarie Island, south-west Pacific, that sits within an intra-oceanic transpressive regime. For decades, the presence or absence of a shallow magma body …
-
Teleseismic P Wave Attenuation in the Upper Mantle Beneath the United States
… wave amplitude spectra were analyzed to examine seismic attenuation patterns in the upper mantle. 2.5 million inter-station P wave spectral ratios were inverted for maps of relative t* variations across the United States in multiple frequency bands between 0.08 and 2 Hz. Broader frequency bands …
-
A fault-controlled geothermal system in Tarutung (North Sumatra, Indonesia)investigated by seismological analysis
The seismic structure (Vp, Vp/Vs, and Qp anomalies) contributes to the physical properties and the lithology of rocks and possible fluid distribution in the region. The Vp model images the geometry of the Tarutung and the Sarulla basins. Both basins have a depth of around 2.0 km. High Vp/Vs and …
-
Viscoelastic full-waveform inversion: treating attenuation uncertainty, characterizing cross-talk, and quantifying confidence in inversion results
… the subsurface properties which affect seismic wave propagation but it is often limited by simplistic treatment of wave propagation physics. In particular, attenuation and dispersion, which play major roles in most seismic experiments, are commonly neglected. This omission often occurs …
-
Seismic Imaging of the Global Asthenosphere using SS Precursors
… While this layer is often characterized by low seismic velocity and high seismic attenuation, the global structure of the asthenosphere remains poorly understood. In this dissertation, twelve years of SS precursors reflected off the top and bottom of the asthenosphere, namely, the LAB and the …
-
Characterizing intrinsic and stratigraphic Q in VSP data with information measures
… in finely layered geological media modify a seismic pulse as it propagates. This effect, called stratigraphic filtering, or extrinsic attenuation, is characterized by strong attenuation and dispersion of seismic amplitudes. It is similar to, and in fact very difficult to distinguish from, the …
-
Modeling, imaging and waveform-inversion in attenuative anisotropic media
Seismic attenuation, which is often anisotropic, has a profound influence on wave propagation and seismic processing. In addition to application of attenuation coefficients in lithology and fluid discrimination, compensation for angle-dependent attenuation and velocity dispersion is critically …
-
Seismic studies of 3-D elastic and anelastic structure of crust and upper mantle in Western China
… Indian-Eurasian continental collision. It is seismically very active even in some populous regions. Therefore, it is important to study the crustal and upper mantle structure beneath western China to understand the tectonics of the region and provide constraint for earthquake hazards. There …
-
URBAN SEISMIC AMBIENT NOISE ANALYSIS: INNOVATIONS AND APPLICATIONS
Seismic ambient noise generated by human activities provides an opportunity to monitor aboveground human activities without intruding on privacy. However, extracting specific signals from noisy seismic noise is challenging. Seismic ambient noise also contains information about the underground …
-
Surface wave propagation in 3-D anelastic media
… dispersion becomes more important than wave attenuation in longer period surface waves. In tomography studies, ray theory breaks down and finite frequency effects become important when the length scale of heterogenities are smaller than seismic wavelength. Finite frequency effects in 3-D …
-
Numerical modelling and observations of nuclear-explosion coda wavefields
Frequency-dependent earthquake coda attenuation values are often reported; however such measurements usually depend on the types of the attenuation models employed. In this thesis, I use numerical modeling of Peaceful Nuclear Explosion (PNE) codas at far regional to teleseismic distances to compare …