Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Geophysics

Supervisor

Dr. Robert Shcherbakov

Abstract

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 western Pacific regions compared to the eastern Pacific regions. It is also observed that, on average, the exponent of the modified Omori law—the p-value—in the eastern Pacific regions is higher than in the western Pacific regions. Additionally, it was found that there is no significant change in b-values with an increase in magnitude. A positive correlation was found, however, between p-values and magnitude. It is proposed that the spatial heterogeneity of materials on the fault zone has an effect on the variation of the values of these statistical parameters.


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