Percival, Donald BDucellier, Ariane2022-01-262022-01-262022-01-262022-01-262022-01-262021Ducellier_washington_0250O_23746.pdfhttp://hdl.handle.net/1773/48334Thesis (Master's)--University of Washington, 2021Low-frequency earthquakes (LFEs) are small magnitude (less than 2) earthquakes, with reduced amplitudes at frequencies greater than 10 Hz relative to ordinary small earthquakes. They are usually grouped into families of events, with all the earthquakes of a given family originating from the same small patch on the plate interface and recurring more or less episodically in a bursty manner. In this thesis, I analyze catalogs of events from several LFE families located in Cascadia, Mexico, and the San Andreas Fault. First, for each given family of LFEs, I translate the catalog into a continuous time series defined by the number of events per unit of time. Long-range dependence is a phenomenon that may arise in the statistical analysis of time series data. It relates to the slow rate of decay of the statistical dependence between two points with increasing time interval between the points. I look for evidence of long-range dependence in the time series by analyzing them with several graphical methods. Second, I consider all the LFEs associated with a single family as a point process (a marked point process if magnitude is available). I then model this point process with an Epidemic-Type Aftershock Sequence (ETAS) model and fit the parameters of the model for each LFE family. Finally, I generate synthetic ETAS models using the fitted parameters, in order to verify whether this type of models can produce apparent long-range dependence as observed in the first part of this thesis. The statistical characterization of LFE occurrence could provide important constraints on future mechanical models of LFE generation.application/pdfen-USnoneStatisticsStatisticsThesis