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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Improved teleseismic Green's functions and western Canada mantle structure and evolution

Mercier, Jean-Philippe 05 1900 (has links)
The present thesis is divided into three distinct parts and focuses both on the improvement of deconvolution technique in a teleseismic context for crustal and upper-mantle studies and on the understanding of western Canada structure and evolution through seismic imaging. The first part presents estimates of the P-component of the teleseismic-P Green's functions for three stations of the Canadian National Seismic Network (CNSN) obtained using a new deconvolution technique. Our results show evidence of the principal, first-order scattered Moho phases and, in particular, the Pp_Mp. The second part presents teleseismic receiver functions from 20 broadband three-component seismometers deployed along the MacKenzie-Liard Highway in Canada's Northwest Territories as part of the joint Lithoprobe-IRIS CAnadian NOrthwest Experiment (CANOE). These stations traverse a Paleoproterozoic suture and subduction zone that has been previously documented in detail to mantle depths using seismic reflection profiling. Our results reveal the response of the ~1.8 Ga subduction zone on both the radial and transverse component. The identification of this structure and its comparison with fine-scale mantle layering below the adjacent Slave province and from a range of Precambrian terranes provides an unambiguous connection between fossil subduction and fine-scale, anisotropic mantle layering found beneath cratons. Previous documentation of similar layering below the adjacent Slave province provides strong support for the thesis that early cratonic blocks were stabilized through processes of shallow subduction. The last part presents P- and S wave velocity models for western Canada. In this part, we focus our attention on two distinct features: 1) the transition from Phanerozoic to cratonic mantle in northwestern Canada and 2) the complex tectonic environment at the northern terminus of the Cascadia subduction zone where the plate boundary changes from convergent to transform. We find that the main transition from Phanerozoic to cratonic mantle in northwestern Canada occurs at the Cordilleran deformation front. In northern Cascadia, we have imaged and characterized the signature of the subducting Juan de Fuca plate and observed evidence of subduction beyond the northern edge of the slab. Our result show that the Anahim hotspot track is underlain by a -2% low-velocity zone.
2

Improved teleseismic Green's functions and western Canada mantle structure and evolution

Mercier, Jean-Philippe 05 1900 (has links)
The present thesis is divided into three distinct parts and focuses both on the improvement of deconvolution technique in a teleseismic context for crustal and upper-mantle studies and on the understanding of western Canada structure and evolution through seismic imaging. The first part presents estimates of the P-component of the teleseismic-P Green's functions for three stations of the Canadian National Seismic Network (CNSN) obtained using a new deconvolution technique. Our results show evidence of the principal, first-order scattered Moho phases and, in particular, the Pp_Mp. The second part presents teleseismic receiver functions from 20 broadband three-component seismometers deployed along the MacKenzie-Liard Highway in Canada's Northwest Territories as part of the joint Lithoprobe-IRIS CAnadian NOrthwest Experiment (CANOE). These stations traverse a Paleoproterozoic suture and subduction zone that has been previously documented in detail to mantle depths using seismic reflection profiling. Our results reveal the response of the ~1.8 Ga subduction zone on both the radial and transverse component. The identification of this structure and its comparison with fine-scale mantle layering below the adjacent Slave province and from a range of Precambrian terranes provides an unambiguous connection between fossil subduction and fine-scale, anisotropic mantle layering found beneath cratons. Previous documentation of similar layering below the adjacent Slave province provides strong support for the thesis that early cratonic blocks were stabilized through processes of shallow subduction. The last part presents P- and S wave velocity models for western Canada. In this part, we focus our attention on two distinct features: 1) the transition from Phanerozoic to cratonic mantle in northwestern Canada and 2) the complex tectonic environment at the northern terminus of the Cascadia subduction zone where the plate boundary changes from convergent to transform. We find that the main transition from Phanerozoic to cratonic mantle in northwestern Canada occurs at the Cordilleran deformation front. In northern Cascadia, we have imaged and characterized the signature of the subducting Juan de Fuca plate and observed evidence of subduction beyond the northern edge of the slab. Our result show that the Anahim hotspot track is underlain by a -2% low-velocity zone.
3

Probability that another Intensity X Event could occur in the SE during a 200 year period

Ormsby, Marka Robin 08 1900 (has links)
No description available.
4

Earthquake catastrophe risk management :

Tong, Canon Unknown Date (has links)
Thesis (PhD) -- University of South Australia, 1999
5

Deconvolution of seismic response for linear systems /

Reimer, Richard B. January 1973 (has links)
Also Reimer's dissertation (Ph. D. in Engineering)--University of California, Berkeley, June 1973. / "October 1973." Includes bibliographical references.
6

Structural Response Including Vertical Component of Ground Motion

Piolatto, Alex Joseph 01 December 2009 (has links)
Evidence indicates that the vertical component of ground motion is more significant than previously thought, especially for near fault events. However, many design codes do not reflect the importance of the vertical component of ground motion. Therefore, the purpose of this thesis is to determine what effects the vertical component of ground motion has on a structure by way of comparison. Specifically, structural response due to the lateral components of ground acceleration is compared to structural response due to all three components of ground acceleration. Structural response includes the following parameters: story drift; axial force; shear; torsion; and bending moment. Variables are fundamental period of vibration, ground motion record, and presence of cross-bracing. Through nonlinear dynamic time history analysis, it is shown that the vertical component of ground motion greatly affects axial force response for these short-period frames. However, the story drift is unaffected for the short, medium, and long-period frames. Other parameters show varying degrees of dependence or independence in relation to the vertical component of ground motion.
7

Improved teleseismic Green's functions and western Canada mantle structure and evolution

Mercier, Jean-Philippe 05 1900 (has links)
The present thesis is divided into three distinct parts and focuses both on the improvement of deconvolution technique in a teleseismic context for crustal and upper-mantle studies and on the understanding of western Canada structure and evolution through seismic imaging. The first part presents estimates of the P-component of the teleseismic-P Green's functions for three stations of the Canadian National Seismic Network (CNSN) obtained using a new deconvolution technique. Our results show evidence of the principal, first-order scattered Moho phases and, in particular, the Pp_Mp. The second part presents teleseismic receiver functions from 20 broadband three-component seismometers deployed along the MacKenzie-Liard Highway in Canada's Northwest Territories as part of the joint Lithoprobe-IRIS CAnadian NOrthwest Experiment (CANOE). These stations traverse a Paleoproterozoic suture and subduction zone that has been previously documented in detail to mantle depths using seismic reflection profiling. Our results reveal the response of the ~1.8 Ga subduction zone on both the radial and transverse component. The identification of this structure and its comparison with fine-scale mantle layering below the adjacent Slave province and from a range of Precambrian terranes provides an unambiguous connection between fossil subduction and fine-scale, anisotropic mantle layering found beneath cratons. Previous documentation of similar layering below the adjacent Slave province provides strong support for the thesis that early cratonic blocks were stabilized through processes of shallow subduction. The last part presents P- and S wave velocity models for western Canada. In this part, we focus our attention on two distinct features: 1) the transition from Phanerozoic to cratonic mantle in northwestern Canada and 2) the complex tectonic environment at the northern terminus of the Cascadia subduction zone where the plate boundary changes from convergent to transform. We find that the main transition from Phanerozoic to cratonic mantle in northwestern Canada occurs at the Cordilleran deformation front. In northern Cascadia, we have imaged and characterized the signature of the subducting Juan de Fuca plate and observed evidence of subduction beyond the northern edge of the slab. Our result show that the Anahim hotspot track is underlain by a -2% low-velocity zone. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
8

An energy method for the analysis of structures subjected to earthquakes

McKevitt, William Edward January 1980 (has links)
Work toward developing a simple method for the aseismic design of structures considering energy dissipation as the prime design parameter is reported. Viscous damping is used to represent the non-structural energy dissipating elements in the system, and hysteretic energy dissipation is considered explicitly. A detailed parametric study of the energy dissipation characteristics of single degree of freedom systems is reported first. Here the amount of energy dissipated by both hysteretic and viscous damping mechanisms in each system is determined for various ground motions, viscous damping values, system strengths etc. The results of this study are presented in the form of spectra, relating total energy dissipated, and energy distribution between mechanisms to known system properties. The results and insights gained from the parametric study are incorporated into a design method which accounts explicitly for energy dissipation. The inclusion of a system strength parameter in the input of the proposed method is found to he most useful in terms of the limit state philosophy employed in the most recent editions of building codes. Also if special damping devices are to he built into the structure, this method will facilitate such design. Finally a preliminary study of the energy dissipation characteristics of multi-degree of freedom systems is reported. Here the distribution of energy dissipated by viscous damping and hysteresis, together with the location of the effective dissipating mechanisms within the structure, is studied. In particular the possibility of extrapolation from single degree of freedom spectra to the multi-degree of freedom systems is investigated and shown to give encouraging results. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
9

A method for simulating and representing strong ground motion

Jurkevics, Andrejs January 1978 (has links)
A method for representing and synthesizing strong motion accelerograms is proposed in this thesis. The procedure models an acceleration time-history as a non-stationary second order autoregressive (AR) process. Three AR parameters are determined from the data in a time-adaptive manner. They provide a quantitative description of the time-varying spectral content of the recording. The AB parameters may also be utilized as prediction filter coefficients, enabling one to generate a suite of artificial accelerograms, each having the same time-dependent spectral content as the target record. The simulated time-histories may be used for computing structural response in earthquake-prone areas. This analysis has been extended to include a number of recordings obtained during earthquakes of various magnitudes (M) at a variety of epicentral distances (D). As a result, 'type curves' representing the empirical behaviour of the three AB parameters have been determined. Although incomplete, this information may be used to generate artificial accelerograms for arbitrary combinations of M and D. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate
10

Evaluation, Modeling, and Retrofit of Flat-Slab Buildings subjected to Seismic Loading

January 1995 (has links)
Flat-slab buildings designed and detailed for gravity loads only typically do not have the ability to resist moderate earthquakes without experiencing severe damage. The damage potential of such seismically deficient buildings therefore needs to be assessed and strategies developed to improve their seismic resistance. Punching failure at slab-column connections in non-ductile flat-slab buildings during earthquakes can trigger progressive collapse of floor slabs. Based on the test results of a large number of interior and exterior connections, a methodology is developed to predict shear and unbalanced moment-transfer capacities of connections under combined gravity and lateral loads. Furthermore, a frame analysis procedure is developed based on the equivalent frame concept which targets both the moment-transfer capacity as well as stiffness of the interior and exterior slab-column connections. The approach employs a parametric hysteretic model and is based on the effective slab-width concept. The proposed procedure for evaluating the seismic capacity of flat-slab connections and frames is verified by comparing the calculated and measured responses of two-bay flat-slab subassemblies tested under earthquake-type loading. Seismic reliability against punching failure of slab-column connections in flat-slab buildings designed for gravity loads was investigated using the proposed equivalent frame approach. The reliability analysis indicated that the flat-slab buildings constructed prior to the 1960's could experience significant damage during moderate intensity earthquakes. By limiting the gravity load on floor slabs and by controlling the lateral drift, the potential for punching failure in flat-slab buildings can be minimized. The seismic resistance of older flat-slab buildings can be improved by retrofitting interior connections to protect against progressive collapse and by utilizing infill walls to control lateral drift. An economical connection retrofit scheme is proposed and verified experimentally. The equivalent strut concept is used to model masonry infills whose effectiveness in controlling the lateral drift is demonstrated through theoretical analysis of typical flat-slab frames.

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