Understanding Time-Variant Stress-Strain in Turkey: A Numerical Modeling Approach

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dc.contributor.authorNowak, Stephanie Bethen
dc.contributor.committeechairCoruh, Cahiten
dc.contributor.committeememberChapman, Martin C.en
dc.contributor.committeememberPeavy, Samen
dc.contributor.committeememberKriz, Ronald D.en
dc.contributor.committeememberSpotila, James A.en
dc.contributor.departmentGeosciencesen
dc.date.accessioned2014-03-14T20:07:00Zen
dc.date.adate2005-08-04en
dc.date.available2014-03-14T20:07:00Zen
dc.date.issued2004-11-23en
dc.date.rdate2006-08-04en
dc.date.sdate2005-01-30en
dc.description.abstractOver the past century, a series of large (> 6.5) magnitude earthquakes have struck along the North Anatolian Fault Zone (NAFZ) in Turkey in a roughly East to West progression. The progression of this earthquake sequence began in 1939 with the Ms 8.0 earthquake near the town of Erzincan and continued westward, with two of the most recent ruptures occurring near the Sea of Marmara in 1999. The sequential nature of ruptures along this fault zone implies that there is a connection between the location of the previous rupture and that of the future rupture zones. This study focuses on understanding how previous rupture events and tectonic influences affect the stress regime of the NAFZ and how these stress changes affect the probability of future rupture along any unbroken segments of the fault zone using a two dimensional finite element modeling program. In this study, stress changes due to an earthquake are estimated using the slip history of the event, estimations of rock and fault properties along the fault zone (elastic parameters), and the far-field tectonic influence due to plate motions. Stress changes are not measured directly. The stress regime is then used to calculate the probability of rupture along another segment of the fault zone. This study found that when improper estimates of rock properties are utilized, the stress changes may be under- or over- estimated by as much as 350% or more. Because these calculated stress changes are used in probability calculations, the estimates of probability can be off by as much as 20%. A two dimensional model was built to reflect the interpreted geophysical and geological variations in elastic parameters and the 1939 through 1999 rupture sequence was modeled. The far-field tectonic influence due to plate motions contributed between 1 and 4 bars of stress to the unbroken segments of the fault zone while earthquake events transferred up to 50 bars of stress to the adjacent portions of the fault zone. The 1999 rupture events near Izmit and Düzce have increased the probability of rupture during the next ten years along faults in the Marmara Sea to 38% while decreasing the probability of rupture along the faults near the city of Bursa by ~6%. Large amounts of strain accumulation are interpreted along faults in the Marmara Sea, further compounding the case for a large rupture event occurring in that area in the future.en
dc.description.degreePh. D.en
dc.identifier.otheretd-01302005-161019en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-01302005-161019/en
dc.identifier.urihttp://hdl.handle.net/10919/26072en
dc.publisherVirginia Techen
dc.relation.haspartSNowakDissertation1.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectStress Transferen
dc.subjectFinite Element Modelingen
dc.subjectRupture Probability Analysisen
dc.subjectNorth Anatolian Fault Zoneen
dc.subjectTurkeyen
dc.titleUnderstanding Time-Variant Stress-Strain in Turkey: A Numerical Modeling Approachen
dc.typeDissertationen
thesis.degree.disciplineGeosciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.leveldoctoralen
thesis.degree.namePh. D.en

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