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dc.contributor.advisorThomas H. Jordan.en_US
dc.contributor.authorRichardson, Eliza Bonham, 1974-en_US
dc.contributor.otherMassachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.en_US
dc.date.accessioned2005-08-24T20:02:06Z
dc.date.available2005-08-24T20:02:06Z
dc.date.copyright2002en_US
dc.date.issued2002en_US
dc.identifier.urihttp://hdl.handle.net/1721.1/8062
dc.descriptionThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2002.en_US
dc.descriptionIncludes bibliographical references (p. 181-200).en_US
dc.description.abstractWe measured spectral and time-domain properties of seismic events over a size range that spans magnitudes M [approx.] -2 to 8 in order to study earthquake source processes. In addition, we conducted laboratory experiments to study interseismic behaviors that can influence earthquake nucleation and we developed a model of eathquake rupture to explain the scaling behaviors we observe. To bridge the scale gap between laboratory data and global seismic observations, we studied data from five deep gold mines in the Far West Rand region of South Africa. These mines are seismically active due to daily underground blasting and record [approx.] 1000 events per day from -2 =/< M =/< 3+ close to their sources. Frequency-magnitude relations, spatio-temporal clustering relations and observations of seismic spectra provide evidence that there are two types of events that occur in these mines, which we designate as Type A and Type B. Type-A events are fracture-dominated ruptures of previously intact rock and show an upper magnitude cutoff at M [approx.] 0.5. They are tightly clustered in space and time and occur close to active stope faces. They have scaling properties that agree with other studies of fresh-fracturing seismicity in that apparent stress decreases with magnitude and stress drop increases with magnitude.en_US
dc.description.abstractIn contrast, Type-B events are temporally and spatially distributed throughout the active mining region. They have a lower magnitude cutoff at M [approx.] 0. From frictional scaling laws and observations of source spectra, we deduce that that this lower magnitude cutoff represents the critical patch size for earthquake nucleation in this mining environment. We find that the critical patch size is on the order of 10 m with a critical slip distance on the order of 10-4 m. Type-B events have scaling properties that match extrapolations from tectonic earthquakes. For example, apparent stress and particle velocity increase with magnitude. We develop a kinematic model of increasing rupture velocity with increasing source size to account for the observed scaling of frictional shear events.en_US
dc.description.statementofresponsibilityby Eliza Bonham Richardson.en_US
dc.format.extent200 p.en_US
dc.format.extent12696711 bytes
dc.format.extent12696468 bytes
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/pdf
dc.language.isoengen_US
dc.publisherMassachusetts Institute of Technologyen_US
dc.rightsM.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.en_US
dc.rights.urihttp://dspace.mit.edu/handle/1721.1/7582
dc.subjectEarth, Atmospheric, and Planetary Sciences.en_US
dc.titleEarthquake nucleation and rupture at a range of scales : laboratories, gold mines, and subduction zonesen_US
dc.typeThesisen_US
dc.description.degreePh.D.en_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
dc.identifier.oclc51043638en_US


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