Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 23 for “"Stress Drop"”.
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Moment-radius-stress drop relations and temporal changes in the regional stress from the analysis of small earthquakes in the Matsushiro region, southwest Honshu, Japan
Moment-radius-stress drop relations and composite focal mechanisms were determined for 33 small, shallow, strike slip earthquakes (1.7$MLS4.3) in the Matsushiro region of southwest Honshu, Japan during the period August 1971 through September 1974. Estimates of the scalar moment derived from …
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Laboratory analysis of restrenghtening on simulated faults
Seismic data show that stress drop increases with the logarithm of earthquake recurrence interval (1-5 MPa per decade time). If stress drop is taken as a proxy for fault strength, then the data suggest that faults restrengthen during the quiescent period of the earthquake cycle. Seismic surveys …
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Apparent Stress Estimates of Seismic Events Associated with Underground Mining Operations in Sedimentary Rock Units: Implications for Improving Underground Roof Collapse Warning Systems
… effects and bandwidth limitations. The apparent stress, which provides an estimate of the stress drop (or stress release) associated with a seismic event, is then determined from the product between the modulus of rigidity and the ratio between the radiated seismic energy and static seismic …
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ΧΑΡΑΚΤΗΡΙΣΤΙΚΕΣ ΠΑΡΑΜΕΤΡΟΙ ΣΕΙΣΜΙΚΗΣ ΠΗΓΗΣ ΜΕ ΤΗ ΜΕΘΟΔΟ ΤΗΣ ΑΝΤΙΣΤΡΟΦΗΣ ΤΩΝ ΚΥΜΑΤΩΝ ΧΩΡΟΥ: ΕΛΛΑΔΑ ΚΑΙ Η ΕΥΡΥΤΕΡΗ ΠΕΡΙΟΧΗ ΤΗΣ
… DURATION, RAPTURE COMPLEXITY, SEISMIC MOMENT AND STRESS DROP. FIVE AREAS HAVE BEEN RECOGNIZED IN THE GREEK REGION WITH SEPARATE SOURCE PROPERTIES. EARTHQUAKES CAUSED BY NORMAL FAULTING HAVE RELATIVELY SIMPLE RAPTURE PROCESS COMPARED TO THE ONES DUE TO TRANSFORM FAULTS AND DURATION OF THE SOURCE …
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Defects and Rearrangements in Disordered Solids
… procedure that classifies events by stress drop, energy drop, and reversibility under two protocols. Somewhat surprisingly, we find a large population of contact change events that have no associated stress drop. Reversible events become more common at high pressures above a packing …
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Crustal heterogeneities and complexities of fault processes
… medium in a transform domain with a deviatoric stress field imposed at remote distances (compressive NE − SW, tensile NW − SE). An isotropic compressive stress component is induced outside the asperity, in the direction of the compressive stress axis, and a tensile component in the direction of …
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Characterizing microearthquakes and shallow structure with dense array and optical fibers
… small earthquakes, such as source dimension and stress drop, help us to constrain source physics and assess seismic hazards. Small events carry information about the stress state in the subsurface. They also help us predict the behavior of larger earthquakes. However, the source properties of …
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Source studies over a wide range in earthquake magnitude
… over the range 10²² to 10²⁵ dyne-cm. Log Brune stress drop was found to be linearly correlated with log moment with a slope of approximately unity below 10²¹ dyne-cm, and highly correlated but with a slightly smaller slope above that point. For lower moments, stress drops increase with moment …
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Quantitative Analysis of Acoustic Emission From Rock Fracture Experiments
… Using the calibration information, magnitude, stress drop, dimension and energy were successfully estimated for 21 AE events recorded in the tensile region of the tunnel wall. Magnitudes were in the range -7.5
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Bauschinger effect in Nb and V microalloyed line pipe steels
… (more than 400 mm) welded pipes the strength drop from plate to pipe, as a result of reverse deformation (the Bauschinger effect), depends on steel grade, namely microalloying element content, and processing. In this project the microstructure of two Nb- and V-microalloyed steels has been …
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Kinetics of Plastic Flow in Polycrystal Plasticity
… are based on the isotropic mechanical threshold stress continuum model. A modified power law is used to determine slip system activity without introducing artificial strain rate sensitivity. In addition, a slip system hardening law is introduced that is capable of modeling stage IV hardening. The …
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Earthquake nucleation and rupture at a range of scales : laboratories, gold mines, and subduction zones
… of fresh-fracturing seismicity in that apparent stress decreases with magnitude and stress drop increases with magnitude.
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Statistics of slip avalanches in sheared amorphous materials based on atomistic simulation
… distribution of the magnitude of serrations in stress-strain curves. Mesoscale models of amorphous plasticity, depending on assumptions of the interaction between slipped sites, give different predictions of scaling exponents. Atomistic simulation, which does not rely on such assumptions, offers …
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LES of pulsatile flow in the models of arterial stenosis and aneurysm
… In the additive case the upper wall pressure drop is larger than the non-additive case. Due to the large amplitude of the oscillation, transition happens earlier and the peak turbulent kinetic energy occurs at the post-lip of the stenosis. The intensity of the turbulent kinetic energy is …
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Poroelastic modeling of groundwater and hydrocarbon reservoirs : investigating the effects of fluid extraction on fault stability
… of poroelasticity was used to calculate the stress changes resulting from fluid flow. Then, the resulting fault stability was evaluated with the the Coulomb Failure Function ([Delta]CFF). A COMSOL and MATLAB workflow was used to derive the results. Two applications were completed. The primary …
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Understanding the Yield Behaviour of Single Crystal Ni-based Superalloys
… creep were observed which was associated with a drop in the stress. The stress drop is associated with the formation of stacking fault shear and was dependent on the composition of the alloy. The fault structure is the same as those observed in post-creep samples. Chromium and cobalt were also …
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The role of roughness in earthquake source physics
… geometric asperities and a locally heterogeneous stress field, which affect the nucleation and propagation of shear rupture. I study this effect numerically at the scale of small earthquakes, in which realistic geometry and friction law parameters can be incorporated in the model. The numerical …
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Analysis of seismo-acoustic emission from ice fracturing events during SIMI’94
… because it allows one to identify areas of high stress concentration and "hot spots" in ridge building process. The identification of source mechanisms is based on the radiation patterns of the events. This identification was carried out through the analysis of the seismo-acoustic emission of …
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Seismic Source and Attenuation Studies in the Central and Eastern United States
… of the aftershock sequence, and the Coulomb stress modeling that explains the triggering mechnanism of those aftershocks. Second, I examine the S-wave attenuation at critical short hypocentral distances (< 60 km) using the aftershock data. The observed S-wave amplitudes decay as a function of …
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Caracterización de sismicidad intraplaca de profundidad intermedia en la zona de subducción chilena
… A partir de esto se obtienen los valores de stress drop que se condicen con lo esperado para la sismicidad intraplaca de profundidad intermedia. Utilizando Template Matching se buscan réplicas de los sismos. Así se consigue caracterizar la fragilidad de la zona y el proceso de deshidratación …
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