Geophysics and Seismology Commons^™

Approaches To Model Non-Uniqueness And Site Complexity For Non-Invasive Shear-Wave Depth Profiling, Christopher Boucher

Electronic Thesis and Dissertation Repository

Shear-wave velocity (VS) depth profiling and associated seismic site classifications were performed at 15 sites across Metro Vancouver, British Columbia using passive seismic and surface wave methods. Inversion model parameters are constrained at each site using nearby geodata in combination with developing regression models of shear-wave velocity with depth for three primary stratigraphic units. Statistical methods such as a Bayesian Information Criterion are applied post-inversion to evaluate models between and within varying parameterizations. Data evaluation metrics, including the use of microtremor horizontal-to-vertical spectral ratios (MHVSRs), are applied to identify two common deviations from the simple case of normally dispersive laterally …

A Transformer-Based Classification System For Volcanic Seismic Signals, Anthony P. Rinaldi, Cindy Mora Stock, Cristián Bravo Roman, Alexander Hemming

Undergraduate Student Research Internships Conference

Monitoring volcanic events as they occur is a task that, to this day, requires significant human capital. The current process requires geologists to monitor seismographs around the clock, making it extremely labour-intensive and inefficient. The ability to automatically classify volcanic events as they happen in real-time would allow for quicker responses to these events by the surrounding communities. Timely knowledge of the type of event that is occurring can allow these surrounding communities to prepare or evacuate sooner depending on the magnitude of the event. Up until recently, not much research has been conducted regarding the potential for machine learning …

Geomechanical Modeling Of A Fault During Fluid Injection, Charles Kw Hulls

Electronic Thesis and Dissertation Repository

The injection of fluid into rock masses as a part of industrial processes, such as hydraulic fracturing, can lead to an increase in seismic activity. The movement of the injected fluid and resulting stresses can be simulated and analyzed. One aspect of this analysis is the predicted rate of seismic activity, obtained via the Dietrich rate-and-state law and the Coulomb Failure Stress. This work produces simulations for two fracturing scenarios in the Duvernay Shale region. Model parameters, such as layer permeability and timing of fault slip, are varied to determine their impact on the model results. The simulated results show …

Examining Κ, The High Frequency Spectral Decay Parameter, In Eastern Canada, Samantha M. Palmer

Electronic Thesis and Dissertation Repository

This thesis examines the ground motion modeling parameter kappa (κ) in the stable continental region of eastern Canada. Kappa characterizes the decay of spectral amplitudes at high frequencies due to near-surface material de-amplification and is important in seismic hazard assessments. Kappa has significant economic and seismic safety implications for critical infrastructure such as nuclear power plants and dams.

To examine kappa in eastern Canada, a database of ground motions to analyze near-source ground motion characteristics is developed. The database consists of ground motion records from 3357 earthquakes of moment magnitude (M) ≥1.5 recorded within 150 km of 25 …

Testing Aftershock Forecasts Using Bayesian Methods, Elisa Dong

Electronic Thesis and Dissertation Repository

The presence of strong aftershocks can increase the seismic hazard following a large earthquake and should be considered for operational earthquake forecasting and risk management. Aftershock forecasts are generated from seismicity models during the evolution of the aftershock sequence. This work compares quantitative test results of the forecasting abilities for three competing aftershock rate models - the modified Omori law, the Epidemic Type Aftershock Sequence model, and the compound Omori law - to identify the best performing model for forecasting the largest aftershock during the early aftershock sequence. Forecasts of large aftershock probabilities are generated by either the Extreme Value …