The Experts below are selected from a list of 270786 Experts worldwide ranked by ideXlab platform
Chengjie Xiong - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a simple step-Stress life test with a random Stress-Change time
IEEE Transactions on Reliability, 2006Co-Authors: Chengjie Xiong, Kejun ZhuAbstract:This paper studies a variation of a simple step-Stress life testing in which the Stress Change time is random, and the test is subject to type II censoring. We assume that only two order statistics from the test are observed. The first observed order statistic is the Stress Change time from a low level Stress to a high level Stress during the testing, and the second observed order statistic is the final failure time when the test is censored. We first present the joint probability distribution of the two order statistics observed from the simple step-Stress accelerated life test. Maximum likelihood estimates, and the method of moment estimates for model parameters based on the joint distribution are considered. We also present the exact confidence interval estimates for the model parameters based on various pivotal quantities, and demonstrate the estimation procedure by a simulated example.
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Step-Stress life-testing with random Stress-Change times for exponential data
IEEE Transactions on Reliability, 1999Co-Authors: Chengjie Xiong, G.a. MillikenAbstract:This paper studies statistical models in step-Stress accelerated life-testing when the Stress-Change times are random. The marginal lifetime distribution of a test unit under a step-Stress test plan when the Stress Change times are random variables is presented. Maximum likelihood estimates for model parameters based on both the marginal and conditional life distributions are considered. An optimum test plan is explored for simple step-Stress test when the Stress Change time is an order statistic from the exponential lifetime under the low-Stress level.
Kejun Zhu - One of the best experts on this subject based on the ideXlab platform.
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Analysis of a simple step-Stress life test with a random Stress-Change time
IEEE Transactions on Reliability, 2006Co-Authors: Chengjie Xiong, Kejun ZhuAbstract:This paper studies a variation of a simple step-Stress life testing in which the Stress Change time is random, and the test is subject to type II censoring. We assume that only two order statistics from the test are observed. The first observed order statistic is the Stress Change time from a low level Stress to a high level Stress during the testing, and the second observed order statistic is the final failure time when the test is censored. We first present the joint probability distribution of the two order statistics observed from the simple step-Stress accelerated life test. Maximum likelihood estimates, and the method of moment estimates for model parameters based on the joint distribution are considered. We also present the exact confidence interval estimates for the model parameters based on various pivotal quantities, and demonstrate the estimation procedure by a simulated example.
G.a. Milliken - One of the best experts on this subject based on the ideXlab platform.
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Step-Stress life-testing with random Stress-Change times for exponential data
IEEE Transactions on Reliability, 1999Co-Authors: Chengjie Xiong, G.a. MillikenAbstract:This paper studies statistical models in step-Stress accelerated life-testing when the Stress-Change times are random. The marginal lifetime distribution of a test unit under a step-Stress test plan when the Stress Change times are random variables is presented. Maximum likelihood estimates for model parameters based on both the marginal and conditional life distributions are considered. An optimum test plan is explored for simple step-Stress test when the Stress Change time is an order statistic from the exponential lifetime under the low-Stress level.
F. Masson - One of the best experts on this subject based on the ideXlab platform.
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Seismic cycle Stress Change in western Taiwan over the last 270 years
Geophysical Research Letters, 2010Co-Authors: M. Mouyen, R. Cattin, F. MassonAbstract:[1] The island of Taiwan is affected by intense seismic activity, which includes large events as the disastrous 1999 Chi‐Chi earthquake. To improve seismic hazard assessment in this area, we estimate the effect of both interseismic loading and major events since 1736 on the state of Stress of major active faults. We focus our approach on western Taiwan, which is the most densely populated part of Taiwan. We pay a specific attention to faults geometry and to both interseismic and coseismic slip distributions. Our results suggest that both earthquakes and interseismic loading before 1999 increase the Coulomb Stress in the north‐western part of the Chelungpu fault, a region which experienced the highest coseismic slip during the Chi‐Chi earthquake. More importantly our results reveal a Coulomb Stress increase in the southern part of the Changhua thrust fault, below a densely populated area. Citation: Mouyen, M., R. Cattin, and F. Masson (2010), Seismic cycle Stress Change in western Taiwan over the last 270 years, Geophys. Res. Lett., 37, L03306,
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Seismic cycle Stress Change in western Taiwan over the last 270 years
Geophysical Research Letters, 2010Co-Authors: M. Mouyen, Rodolphe Cattin, F. MassonAbstract:The island of Taiwan is affected by intense seismic activity, which includes large events as the disastrous 1999 Chi-Chi earthquake. To improve seismic hazard assessment in this area, we estimate the effect of both interseismic loading and major events since 1736 on the state of Stress of major active faults. We focus our approach on western Taiwan, which is the most densely populated part of Taiwan. We pay a specific attention to faults geometry and to both interseismic and coseismic slip distributions. Our results suggest that both earthquakes and interseismic loading before 1999 increase the Coulomb Stress in the north-western part of the Chelungpu fault, a region which experienced the highest coseismic slip during the Chi-Chi earthquake. More importantly our results reveal a Coulomb Stress increase in the southern part of the Changhua thrust fault, below a densely populated area.
Jeanne L Hardebeck - One of the best experts on this subject based on the ideXlab platform.
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The impact of static Stress Change, dynamic Stress Change, and the background Stress on aftershock focal mechanisms
Journal of Geophysical Research: Solid Earth, 2014Co-Authors: Jeanne L HardebeckAbstract:The focal mechanisms of earthquakes in Southern California before and after four M ≥ 6.7 main shocks provide insight into how fault systems respond to Stress and Changes in Stress. The main shock static Stress Changes have two observed impacts on the seismicity: changing the focal mechanisms in a given location to favor those aligned with the static Stress Change and changing the spatial distribution of seismicity to favor locations where the static Stress Change aligns with the background Stress. The aftershock focal mechanisms are significantly aligned with the static Stress Changes for absolute Stress Changes of ≥ 0.02 MPa, for up to ~20 years following the main shock. The dynamic Stress Changes have similar, although smaller, effects on the local focal mechanisms and the spatial seismicity distribution. Dynamic Stress effects are best observed at long periods (30–60 s) and for metrics based on repeated Stress cycling in the same direction. This implies that dynamic triggering operates, at least in part, through cyclic shear Stress loading in the direction of fault slip. The background Stress also strongly controls both the preshock and aftershock mechanisms. While most aftershock mechanisms are well oriented in the background Stress field, 10% of aftershocks are identified as poorly oriented outliers, which may indicate limited heterogeneity in the postmain shock Stress field. The fault plane orientations of the outliers are well oriented in the background Stress, while their slip directions are not, implying that the background Stress restricts the distribution of available fault planes.
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aftershocks are well aligned with the background Stress field contradicting the hypothesis of highly heterogeneous crustal Stress
Journal of Geophysical Research, 2010Co-Authors: Jeanne L HardebeckAbstract:[1] It has been proposed that the crustal Stress field contains small-length-scale heterogeneity of much larger amplitude than the uniform background Stress. This model predicts that earthquake focal mechanisms should reflect the loading Stress rather than the uniform background Stress. So, if the heterogeneous Stress hypothesis is correct, focal mechanisms before and after a large earthquake should align with the tectonic loading and the earthquake-induced static Stress perturbation, respectively. However, I show that the off-fault triggered aftershocks of the 1992 M7.3 Landers, California, earthquake align with the same Stress field as the pre-Landers mechanisms. The aftershocks occurred on faults that were well oriented for failure in the pre-Landers Stress field and then loaded by the Landers-induced static Stress Change. Aftershocks in regions experiencing a 0.05 to 5 MPa coseismic differential Stress Change align with the modeled Landers-induced static Stress Change, implying that they were triggered by the Stress perturbation. Contrary to the heterogeneous Stress hypothesis, these triggered aftershocks are also well aligned with the pre-Landers Stress field obtained from inverting the pre-Landers focal mechanisms. Therefore, the inverted pre-Landers Stress must represent the persistent background Stress field. Earthquake focal mechanisms provide an unbiased sample of the spatially coherent background Stress field, which is large relative to any small-scale Stress heterogeneity. The counterexample provided by the Landers earthquake is strong evidence that the heterogeneous Stress model is not widely applicable.
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the static Stress Change triggering model constraints from two southern california aftershock sequences
Journal of Geophysical Research, 1998Co-Authors: Jeanne L Hardebeck, Julie J Nazareth, Egill HaukssonAbstract:Static Stress Change has been proposed as a mechanism of earthquake triggering. We quantitatively evaluate this model for the apparent triggering of aftershocks by the 1992 M_W 7.3 Landers and 1994 M_W 6.7 Northridge earthquakes. Specifically, we test whether the fraction of aftershocks consistent with static Stress Change triggering is greater than the fraction of random events which would appear consistent by chance. Although static Stress Changes appear useful in explaining the triggering of some aftershocks, the model's capability to explain aftershock occurrence varies significantly between sequences. The model works well for Landers aftershocks. Approximately 85% of events between 5 and 75 km distance from the mainshock fault plane are consistent with static Stress Change triggering, compared to ∼50% of random events. The minimum distance is probably controlled by limitations of the modeling, while the maximum distance may be because static Stress Changes of <0.01 MPa trigger too few events to be detected. The static Stress Change triggering model, however, can not explain the first month of the Northridge aftershock sequence significantly better than it explains a set of random events. The difference between the Landers and Northridge sequences may result from differences in fault strength, with static Stress Changes being a more significant fraction of the failure Stress of weak Landers-area faults. Tectonic regime, regional Stress levels, and fault strength may need to be incorporated into the static Stress Change triggering model before it can be used reliably for seismic hazard assessment.
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The static Stress Change triggering model: Constraints from two southern California aftershock sequences
Journal of Geophysical Research: Solid Earth, 1998Co-Authors: Jeanne L Hardebeck, Julie J Nazareth, Egill HaukssonAbstract:Static Stress Change has been proposed as a mechanism of earthquake triggering. We quantitatively evaluate this model for the apparent triggering of aftershocks by the 1992 M_W 7.3 Landers and 1994 M_W 6.7 Northridge earthquakes. Specifically, we test whether the fraction of aftershocks consistent with static Stress Change triggering is greater than the fraction of random events which would appear consistent by chance. Although static Stress Changes appear useful in explaining the triggering of some aftershocks, the model's capability to explain aftershock occurrence varies significantly between sequences. The model works well for Landers aftershocks. Approximately 85% of events between 5 and 75 km distance from the mainshock fault plane are consistent with static Stress Change triggering, compared to ∼50% of random events. The minimum distance is probably controlled by limitations of the modeling, while the maximum distance may be because static Stress Changes of
