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dc.contributor.advisorMorozov, Igoren_US
dc.creatorZhang, Chaoyingen_US
dc.date.accessioned2009-04-23T14:49:03Zen_US
dc.date.accessioned2013-01-04T04:29:41Z
dc.date.available2010-05-04T08:00:00Zen_US
dc.date.available2013-01-04T04:29:41Z
dc.date.created2009en_US
dc.date.issued2009en_US
dc.date.submitted2009en_US
dc.identifier.urihttp://hdl.handle.net/10388/etd-04232009-144903en_US
dc.description.abstractFrequency-dependent earthquake coda attenuation values are often reported; however such measurements usually depend on the types of the attenuation models employed. In this thesis, I use numerical modeling of Peaceful Nuclear Explosion (PNE) codas at far regional to teleseismic distances to compare two of such models, namely the conventional frequency-dependent attenuation with parameters (Q0, ¦Ç) defined by Qcoda(f) = Q0f¦Ç and frequency-independent effective attenuation (Qe) with geometrical attenuation (¦Ã). The results favour strongly the (¦Ã, Qe) model and illustrate the mechanisms leading to apparent Qcoda(f) dependencies. Tests for variations of the crustal velocity structures show that the values of ¦Ã are stable and related to lithospheric structural types, and the inverted Qe values can be systematically mapped into the true Swave attenuation factors within the crust. Modeling also shows that ¦Ã could increase in areas where relatively thin attenuating layers are present within the crust; such areas could likely be related to younger and active tectonics. By contrast, when interpreted by using the traditional (Q0,¦Ç) approach, the synthetic coda shows a strong and spurious frequency dependence with ¦Ç ¡Ö 0.5, which is also similar to many published observations. Observed Lg codas from two Peaceful Nuclear Explosions located in different areas in Russia show similar values of ¦Ã ¡Ö 0.75¡¤10-2 s-1, which are also remarkably close to the independent numerical predictions in this thesis. At the same time, coda Qe values vary strongly, from 850 in the East European Platform to 2500 within the Siberian Craton. This suggests that parameters ¦Ã and Qe could provide stable and transportable discriminants for differentiating between the lithospheric tectonic types and ages, and also for seismic coda regionalization in nuclear-test monitoring research.en_US
dc.language.isoen_USen_US
dc.subjectseismicen_US
dc.subjectattenuationen_US
dc.subjectscatteringen_US
dc.subjectcodaen_US
dc.subjectmodelingen_US
dc.subjectPeaceful Nuclear Explosionen_US
dc.titleNumerical modelling and observations of nuclear-explosion coda wavefieldsen_US
thesis.degree.departmentGeological Sciencesen_US
thesis.degree.disciplineGeological Sciencesen_US
thesis.degree.grantorUniversity of Saskatchewanen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Science (M.Sc.)en_US
dc.type.materialtexten_US
dc.type.genreThesisen_US
dc.contributor.committeeMemberMerriam, James B.en_US
dc.contributor.committeeMemberKoustov, Alexandre V. (Sasha)en_US
dc.contributor.committeeMemberButler, Samuel L.en_US
dc.contributor.committeeMemberAnsdell, Kevin M.en_US


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