Geophysics and Seismology Commons^™

New Gps Time Series Analysis And A Simplified Model To Compute An Accurate Seasonal Amplitude Of Tropospheric Delay, Hadis Samadi Alinia

Electronic Thesis and Dissertation Repository

Horizontal and vertical deformation of the Earth’s crust is due to a variety of different geophysical processes that take place on various spatiotemporal scales. The quality of the observations from spaced-based geodesy instruments such as Global Positioning System (GPS) and differential interferometric synthetic aperture radar (DInSAR) data for monitoring these deformations are dependent on numerous error sources. Therefore, accurately identifying and eliminating the dominant sources of the error, such as troposphere error in GPS signals, is fundamental to obtain high quality, sub-centimeter accuracy levels in positioning results.

In this work, I present the results of double-differenced processing of five years …

A Comparison Of Ground Motion Characteristics From Induced Seismic Events In Alberta With Those In Oklahoma, Krista M. Kaski

Electronic Thesis and Dissertation Repository

Ground motions from potentially-induced seismic events in Alberta of magnitude (M) > 3, recorded within 100 km, are empirically characterized in terms of their response spectral shapes and amplitudes. Ground motions are compared statistically to those from induced events in Oklahoma, as well as to three benchmark ground motion prediction equations (GMPEs), derived from natural events. Discrepancies between Alberta and Oklahoma events appear to be magnitude-dependent, and distance-independent. For events greater than M~4, the ground motions appear equivalent in the two regions. High-frequency motions from M< 3.5 events in Alberta are weaker than those of natural events, even those at shallow focal depths. For larger magnitudes, the residuals between the Alberta motions and benchmark GMPEs (Yenier and Atkinson, 2015; Atkinson, 2015; Abrahamson et al., 2014) suggest that observations are in reasonable accord with the models. These results provide a further understanding of ground motions from induced events in Alberta.

Assessment Of Earthquake Site Amplification And Application Of Passive Seismic Methods For Improved Site Classification In The Greater Vancouver Region, British Columbia, Frederick Andrew Jackson

Electronic Thesis and Dissertation Repository

There is renewed interest to improve seismic microzonation mapping in Greater Vancouver, British Columbia (BC). We investigate local geology as the cause of observed variable ground shaking from the 2015 M 4.7 Vancouver Island earthquake. We observe high amplification at 4-6 Hz on thick sediment and the northern edge of the Fraser River delta, and disparities with current regional seismic microzonation mapping. Site amplification and shear-wave velocity (V_S) are assessed from the first borehole earthquake recordings in BC. We also perform ambient vibration analyses at 13 new locations in southwest BC to highlight suitability of passive seismic methods …

Petrophysical Investigations Of The Marathon Cu-Pge Deposit, Marathon, On, Hiruni Gunawardana

Electronic Thesis and Dissertation Repository

Drill core samples obtained from four mineralized zones of the Marathon Cu-PGE deposit in the Coldwell igneous complex have been investigated for their petrophysical characteristics. Remanent magnetization was used as a possible tool to reorient core samples but a drilling induced overprint magnetization dominated the record. Anisotropy of magnetic susceptibility was measured to provide a proxy for the petrofabric of samples obtained from oriented drill cores; a well-defined planar fabric was found to strike 177 and dip 25°W, with down-dip lineation, in excellent agreement with inferred magmatic flow direction based on 3D modeling of mineralized footwall troughs. Magnetite rich lithologies …

The First Earthquake Site Assessments In Alberta, Canada, Joseph J. Farrugia

Electronic Thesis and Dissertation Repository

A thorough characterization of the site conditions at Alberta seismic stations is a vital component in assessing seismic hazard in the province. This thesis provides the first earthquake site characterizations in Alberta, including shear-wave velocity (V_S) depth profiles, estimates of the average shear-wave velocity in the upper 30 m (V_S30) and peak frequency (f_peak), and their validation for prediction of earthquake site amplification. National Building Code of Canada site classes are limited to C and D based on V_S30 estimates, with D being the predominant site class. Three …

Using Bolide Airwaves To Estimate Meteoroid Source Characteristics And Window Damage Potential, Nayeob Gi

Electronic Thesis and Dissertation Repository

We examined the far-field infrasonic signals produced by 78 bolides simultaneously detected by U.S. government sensors to determine the mechanisms responsible for interstation spreads in infrasound signal period. These signal period spreads lead to large variances in source energy estimates. Our analysis suggests that while acoustic source height contributes to some extent to the variance in signal periods, the range from the source to the station and in particular station noise plays a more significant role.

By simulating the near-field weak shocks from a suite of well-observed energetic fireballs, we have empirically estimated how often fireball shocks produce overpressure ( …

Developing And Testing A Model Of Site Amplification For Southern Ontario, Sebastian Braganza

Electronic Thesis and Dissertation Repository

Commonly-applied methods to estimate ground-motion amplification for earthquake hazard applications in southern Ontario are highly generalized. Site amplification effects have typically been estimated by a parameter that is not well-known in the region, the time-averaged shear-wave velocity in the top 30 metres of soil; V_S30. Moreover, V_S30 is not well correlated with site amplification in this region. This study develops a model that can better estimate ground motions and shaking intensities in southern Ontario based on readily-available information. The model is based on a site’s peak response frequency (f_peak), which can be estimated from depth-to-bedrock. …

Full-Waveform Inversion With Scaled-Sobolev Preconditioning Applied To Vibroseis Field Data, Benjamin Paul Consolvo

Electronic Thesis and Dissertation Repository

I present an application of a high-resolution subsurface imaging technique known as “full-waveform inversion” (FWI) to a vibroseis seismic dataset from eastern Ohio, USA. The data were collected over a crooked line with rough topography, 3.5 km maximum offsets, and no significant frequency content below 12 Hz. These parameters present challenges to obtaining quality images from FWI. The use of a preconditioner–the ‘scaled-Sobolev preconditioner’ (SSP - Zuberi and Pratt, 2017)–on the gradient of the misfit functional was key to obtaining low wavenumbers without discarding high wavenumbers. The results represent the first successful application of FWI with the SSP to a …

The Application Of Geophysical Inversion Techniques To The Nechalacho Rare Earth Element Deposit, Nt, Derek W. Kouhi

Electronic Thesis and Dissertation Repository

The Nechalacho deposit is a world-class rare earth element deposit located in the Thor Lake region approximately 100 kilometers southwest of Yellowknife, NT, Canada. Located within the Blatchford Lake Intrusion Complex, this deposit has the potential to be a large-scale economic asset due to its relatively shallow and sub-horizontal geometry. In this study, geophysical inversion techniques are used to model subsurface magnetic susceptibility and density in order to delineate the deposit. Isolated and joint inversion of both magnetic and gravity data provides similar models. Each inversion procedure delineates a shallow, sub-horizontal layer of high susceptibility and density in approximately the …

Using Physical And Social Sensors In Real-Time Data Streaming For Natural Hazard Monitoring And Response, Yelena Kropivnitskaya

Electronic Thesis and Dissertation Repository

Technological breakthroughs in computing over the last few decades have resulted in important advances in natural hazards analysis. In particular, integration of a wide variety of information sources, including observations from spatially-referenced physical sensors and new social media sources, enables better estimates of real-time hazard. The main goal of this work is to utilize innovative streaming algorithms for improved real-time seismic hazard analysis by integrating different data sources and processing tools into cloud applications. In streaming algorithms, a sequence of items from physical and social sensors can be processed in as little as one pass with no need to store …

Anisotropic Waveform Tomography: Application To Crosshole Data For Transversely Isotropic Media, Shaun Michael Hadden

Electronic Thesis and Dissertation Repository

Anisotropic Traveltime Tomography and Full Waveform Inversion were applied first to synthetic and then to real data following the development of a transversely isotropic model for handling anisotropy. Best-fitting models of seismic velocity and Thomsen's anisotropy parameters were initially obtained from traveltime tomography, and then used as the starting models for Full Waveform Inversion. The use of a Laplace transform approach effectively damps late arriving S-wave artifacts that introduce errors into the modelling process. The results of the synthetic study highlights the tradeoffs in resolution between the two parameter classes, but verify anisotropic traveltime tomography as a valid method for …

Ground-Motion Prediction Equations For Central And Eastern North America, With Emphasis On Site Effects, Behzad Hassani

Electronic Thesis and Dissertation Repository

The works presented in this thesis are aimed at understanding and modeling earthquake ground motions in central and eastern North America (CENA), with an emphasis on the modeling of site effects. A number of approaches are taken, beginning with analysing of the observed ground-motion amplitudes with respect to a ground-motion prediction equation model (GMPE) of a well recorded region (California) (referenced empirical approach). In this work, we show that the ground-motion amplitudes of CENA earthquakes are very similar to the equivalent California values of Boore et al. (2014; BSSA14) at close distances, at low to moderate frequencies. At regional distances …

Climatic Cycles Recorded In Glacially Influenced Rhythmites Of The Gowganda Formation, Huronian Supergroup, Tim S. Howe, Patricia L. Corcoran, Fred Longstaffe, Elizabeth A. Webb, R Gerhard Pratt

Earth Sciences Publications

The Gowganda Formation of the 2.45–2.2 Ga Huronian Supergroup contains glacially-induced, varve-like rhythmites that potentially preserve a detailed record of climatic conditions during the Paleoproterozoic Era. Four rhythmic couplet thickness records were measured at two outcrops near Wharncliffe, Ontario for the purpose of time-series analysis. The couplets, which range from 1 to 32 mm thick, are composed of alternating layers of siltstone and claystone. Time-series analysis of the couplet thickness records using the MTM Toolkit of Mann and Lees (1996) consistently revealed periodicities in the range of 2.2–2.9 couplets per cycle, which is consistent with climatic cycles such as the …

Characterizing Seismicity In Alberta For Induced-Seismicity Applications, Luqi Cui

Electronic Thesis and Dissertation Repository

This report documents the compilation of a high-quality catalog of earthquakes in Alberta and the surrounding region: the Composite Alberta Seismicity Catalog (CASC). It currently includes events through July 2015. The catalog and its documentation are available for download at www.inducedseismicity.ca. For the determination of the magnitude of completeness (M_c) of the catalog, we map M_c (x_i, y_i, t) across a grid of the region, where x_i and y_i represent the longitude and latitude of center nodes in the grid and t indicates time period. The empirical …

Strength Study Of Zircon Under High Pressure, Ievgeniia Morozova

Electronic Thesis and Dissertation Repository

Zircon (ZrSiO₄) is a strong accessory mineral that can retain U, Th and Hf within its structure. This makes zircon an important material in geochemical and geochronological studies. In addition, the strong thermal shock resistance of zircon allows for dating the formations of melt and impact events and to separate shocked and potentially shocked country rocks. However, the deformation mechanism and microstructure behavior of zircon at high pressure is poorly understood. Therefore, this work aims to study the deformation and texture of zircon in situ at high pressure and room temperature, and also to examine the microstructure of …

Regionally-Adjustable Generic Ground-Motion Prediction Equation, Emrah Yenier

Electronic Thesis and Dissertation Repository

We develop a simulation-based generic ground-motion prediction equation (GMPE) that can be adjusted for use in any region by simple modifications to its key modeling parameters.

First, we determine how to treat ground-motion saturation effects observed at close distances to large magnitude earthquakes in a point-source sense. We model the source and attenuation attributes of well-recorded M ≥ 6 events, considering ground motions originate from an equivalent point source placed at an overall effective distance such that the empirically-observed saturation effects are successfully reproduced. We investigate the trade-offs between source and attenuation modeling parameters through analysis of Fourier amplitudes for …

Seismicity Processes In The Charlevoix Seismic Zone, Eastern Canada, Azadeh Fereidoni

Electronic Thesis and Dissertation Repository

The Charlevoix Seismic Zone (CSZ) is the most seismically active region in eastern Canada, based on the historical and current rate of activity. Several papers contend that the current seismicity in the CSZ represents long-lived aftershock sequences of the 1663 M~7 earthquake, in which the aftershock activity has persisted for hundreds of years. The aim of this thesis is to explore the influence of the 1663 earthquake on the current seismicity in the CSZ. The first part of the thesis has focused on developing a comprehensive earthquake database required for analysis of seismicity. The second part of the thesis has …

Magnitude Estimation For Earthquake And Tsunami Early Warning Systems, Attieh Eshaghi

Electronic Thesis and Dissertation Repository

In this study, different magnitude estimation methods were investigated for application to earthquake early warning (EEW) and tsunami early warning systems. This integrated study is divided into two main parts. First, I used strong motion accelerograms recorded by borehole and surface stations from the Kiban Kyoshin network (KiK-net) for Japanese earthquakes with moment magnitude (M) ≥ 5.0 in order to develop ground motion prediction equations (GMPEs). I developed new GMPEs for peak ground acceleration (PGA) and peak ground velocity (PGV) using two different catalogs. The first catalog included earthquakes with 5.0 ≤ M ≤ 8.1 from 1998-2010. In …

Statistical Analysis And Computer Modelling Of Volcanic Eruptions, Laura Anabelle Sanchez

Electronic Thesis and Dissertation Repository

Volcanism is an important mechanism by which internal heat is transported to the Earth's surface and volcanic eruptions are the results of the dynamics of a complex system and are characterized by non-trivial temporal correlations. Understanding the processes involved in volcano formation and magma ascent are crucial to develop better hazard assessment techniques. This study focuses on three main points: understanding caldera formation in the solar system, investigating the global temporal behaviour of volcanic eruptions and understanding the nonlinear interactions taking place in the solid crust which lead to an eruption.

In chapter 2, I first examine the distribution of …

Hydrogeological And Thermal Sustainability Of Geothermal Borehole Heat Exchangers, S. Emad Dehkordi

Electronic Thesis and Dissertation Repository

Assessment of the current approach taken by guidelines and design methods of vertical closed loop heat exchangers shows that often groundwater flow is either disregarded or is not methodically incorporated. The state of scientific research in this arena reveals that overlooking the groundwater flow in the design procedure may not always be a correct assumption. The significance of advective heat transport compared to conduction is defined by the groundwater flux or Darcy velocity which heavily depends on the hydraulic conductivity of the ground, followed by the hydraulic gradient which has a relatively limited range. A sensitivity analysis on ground and …

Spatial Heterogeneities In A Simple Earthquake Fault Model, Javad Kazemian

Electronic Thesis and Dissertation Repository

Natural earthquake fault systems are composed of a variety of materials with different spatial configurations a complicated, inhomogeneous fault surface. The associated inhomogeneities with their physical properties can result in a variety of spatial and temporal behaviors. As a result, understanding the dynamics of seismic activity in an inhomogeneous environment is fundamental to the investigation of the earthquakes processes.

This study presents the results from an inhomogeneous earthquake fault model based on the Olami-Feder-Christensen (OFC) and Rundle-Jackson-Brown (RJB) cellular automata models with long-range interactions that incorporates a fixed percentage of stronger sites, or ‘asperity cells’, into the lattice. These asperity …

Stochastic Simulation Of Multiple-Station Ground Motions And Its Applications, Taojun Liu

Electronic Thesis and Dissertation Repository

Approaches to simulate single- and multiple-component multiple-station ground motion records with target spatial coherency and spatial correlation structures are developed for scenario events in this study. To develop the approaches, spatial correlation of the Fourier amplitude spectrum for a random orientation and for two orthogonal directions is assessed, and empirical equations are suggested. Moreover, spatial coherency of ground motions for two orthogonal horizontal directions is estimated using actual records from seven seismic events. Empirical coherency function is suggested for the components of records in two orthogonal horizontal directions at single and multiple recording stations. It was also found that the …

Estimating Subsurface Anisotropy: Combining Waveform Tomography And Simulated Annealing, Michael Victor Afanasiev

Electronic Thesis and Dissertation Repository

Crosshole seismic tomography has been used by Vale to provide geophysical images of mineralized massive sulphides in the Eastern Deeps deposit at Voisey's Bay. High resolution seismic images are presented by applying acoustic waveform tomography to these data. In waveform tomography, an initial model is required which predicts the first arrival traveltimes to within a half-cycle of the lowest frequency in the data. Because seismic velocity anisotropy can be significant, the initial model must quantify the anisotropy, as well as the velocity, in order to meet the half-cycle criterion.

In our case study, difficulties were encountered in generating an accurate …

Strategies For Visco-Acoustic Waveform Inversion In The Laplace-Fourier Domain, With Application To The Nankai Subduction Zone, Rie Kamei

Electronic Thesis and Dissertation Repository

Waveform inversion is a non-linear and ill-posed inverse problem, with the objective of utilizing the full information content of recorded seismic waveforms. A Laplace-Fourier domain implementation allows a natural `multiscale' approach that mitigates the non-linearity and ill-posedness by inverting low-frequency, early arrival data in the initial stages of inversion. High-frequency components, and late arrivals are incorporated at a later stage. This allows the development of robust inversion strategies capable of handling large wide-angle crustal surveys, leading to reliable, high-resolution velocity and attenuation models of crustal structures. I apply waveform inversion to extract a P-wave velocity model of the active megasplay …

Technique Design To Increase In-Situ Electrical Connections In A Cubic Anvil Press, Marie April Burford

Electronic Thesis and Dissertation Repository

An experimental technique designed to increase in-situ electrical connections in a cubic anvil press has been developed. Two encompassing cell designs (extruded gasket and pre-formed gasket) were tested with several electrical barrier methods: PVD coatings, G-10/FR-4 and Canvas Electrical (C. E.) phenolic, Teflon and Al ceramic tubing.

Many variations of techniques were attempted and each (n)^th attempt was founded on the experience from/observation of the results obtained with the (n-1)^thtechnique variation. Eighteen pressure cell configurations were designed and tested. The cells with self-extruded gaskets were unsuccessful due to the destructive nature of the extruding gaskets on the …

An Investigation Into Earthquake Ground Motion Characteristics In Japan With Emphasis On The 2011 M9.0 Tohoku Earthquake, Hadi Ghofrani

Electronic Thesis and Dissertation Repository

In this integrated study, ground-motion characteristics of one of the most devastating earthquakes in history, the 11^th March 2011 Tohoku-oki earthquake (moment magnitude (M) 9.0), are investigated. The investigation centers on developing empirical and simulated-based ground-motion prediction models for this earthquake. These models allow prediction of expected ground motions from large interface (mega-thrust) earthquakes and estimation of their variability due to variability in input parameters, specifically source characteristics (e.g. slip distributions), propagation path, and site effects.

This research work can be divided into two main parts. In the first part, the influence of regional geologic structure, in …

Studies Of Aftershock Sequences Of Large Subduction Zone Earthquakes, Armick Ivanian

Electronic Thesis and Dissertation Repository

Amongst the different types of earthquakes, it is observed that the mega-thrust earthquakes, which occur in subduction zones, are the most devastating. The aftershock sequences following the mega-thrust earthquakes can also increase the level of seismic hazard, even in remote areas away from the mainshock fault zone. This thesis examines the statistical parameters of aftershock sequences of large subduction zone earthquakes that have occurred in the western and eastern Pacific Ocean. These parameters are vital for seismic hazard assessment of regions located near subduction zones. The results show that, on average, the Gutenberg-Richter exponent—the b-value—is markedly higher in the …

Relationships Between Earthquake Ground Motions And Modified Mercalli Intensity, Andrea Sweny

Electronic Thesis and Dissertation Repository

With widespread Internet use, web-based earthquake reports are a valuable source of felt intensitydata with broad geographical coverage. Paired with ground motion data, Internet surveys like theUSGS Did You Feel It? (DYFI) website can be used to derive relationships between ground motionparameters and Modified Mercalli Intensity (MMI). These are particularly important for regionswith sparse seismographic coverage where the quality and density of intensity data may be superiorto ground motion data. MMI-ground motion relationships are also needed to infer ground motionsof historical earthquakes.

Using well-documented earthquakes in across North America, we analyze correlations betweenfelt intensity and ground motions, including peak ground …

Seismic Microzonation Of Great Toronto Area And Influence Of Building Resonances On Measured Soil Responses, Dimitar Genchev Mihaylov

Electronic Thesis and Dissertation Repository

A pilot seismic microzonation of the Greater Toronto Area (GTA) is used to establish the conditions and limitations of geophysical methods for site response investigations in city conditions. Maps of fundamental soil resonant frequencies, amplifications at these frequencies and interpolated average shear wave velocity of top 30 m of soil profile (VS- 30) used in soil classification were compared to the maps of drift thickness and surficial geology for the GTA. The non-applicability of the interpolated VS-30 map for site classification between measured test points is indicated. It is also shown that the soil response cannot be estimated properly using …

Ergodicity And Seismicity Clustering With Applications In Statistical Seismology, Nelson Cho

Electronic Thesis and Dissertation Repository

The implications of understanding fault networks as ergodic systems are addressed here by using the Thirumalai-Mountain metric that identifies effective ergodic periods, when long but finite time intervals are considered. This framework was proven to be useful in statistical seismology studies. Initially, it was established that that the metric can be used to quantify seismicity clustering. Periods of effective ergodicity were characterized by the occurrence of declustered seismicity. This interpretation was implemented for synthetic and seismic data from southern California and Canadian mines.

Next, methods used in the estimation of regional seismic hazard were applied to mining induced seismicity. The …