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Article
Numerical Simulation of M9 Megathrust Earthquakes in the Cascadia Subduction Zone
We estimate ground motions in the Pacific Northwest urban areas during M9 subduction scenario earthquakes on the Cascadia megathrust by simulating wave propagation from an ensemble of kinematic source descript...
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Chapter
Quantification of Fault-Zone Plasticity Effects with Spontaneous Rupture Simulations
Previous studies have shown that plastic yielding in crustal rocks in the fault zone may impose a physical limit to extreme ground motions. We explore the effects of fault-zone nonlinearity on peak ground velo...
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Article
Quantification of Fault-Zone Plasticity Effects with Spontaneous Rupture Simulations
Previous studies have shown that plastic yielding in crustal rocks in the fault zone may impose a physical limit to extreme ground motions. We explore the effects of fault-zone non-linearity on peak ground vel...
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Article
Noble gas migration experiment to support the detection of underground nuclear explosions
A Noble Gas Migration Experiment injected 127Xe, 37Ar, and sulfur hexafluoride into a former underground nuclear explosion shot cavity. These tracer gases were allowed to migrate from the cavity to near-surface a...
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Article
Measurement of Fukushima aerosol debris in Sequim and Richland, WA and Ketchikan, AK
Aerosol collections were initiated at several locations by Pacific Northwest National Laboratory (PNNL) shortly after the Great East Japan earthquake of May 2011. Aerosol samples were transferred to laboratory...
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Article
Underground sources of radioactive noble gas
It is well known that radon is present in relatively high concentrations below the surface of the Earth due to natural decay of uranium and thorium. However, less information is available on the background lev...
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Article
Determination of plutonium isotope ratios at very low levels by ICP-MS using on-line electrochemically modulated separations
Electrochemically modulated separations (EMS) are shown to be a rapid and selective means of extracting and concentrating Pu from complex solutions prior to isotopic analysis by inductively coupled plasma mass...
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Article
Environmental applications of stable xenon and radioxenon monitoring
Characterization of transuranic waste is needed for decisions about waste site remediation. Soil-gas sampling for xenon isotopes can be used to define the locations of spent fuel and transuranic waste. Radioxe...
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Article
Analysis of IAEA environmental samples for plutonium and uranium by ICP/MS in support of international safeguards
A method for the separation and determination of total and isotopic uranium and plutonium by ICP/MS was developed for IAEA samples on cellulose-based media. Preparation of the IAEA samples involved a series of...
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Article
A Condition for Super-shear Rupture Propagation in a Heterogeneous Stress Field
— We have used numerical simulations with the boundary integral equation method to investigate a mechanism to excite super-shear rupture velocities in a homogeneous stress field including an asperity of increa...
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Article
Criticality of Rupture Dynamics in 3-D
—We study the propagation of seismic ruptures along a fault surface using a fourth-order finite difference program. When prestress is uniform, rupture propagation is simple but presents essential differences w...
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Article
Constraints on Stress and Friction from Dynamic Rupture Models of the 1994 Northridge, California, Earthquake
—We have simulated several scenarios of dynamic rupture propagation for the 1994 Northridge, California, earthquake, using a three-dimensional finite-difference method. The simulations use a rate- and slip-wea...
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Article
Detection of thiophenes in the offgas condensate of an oil shale retort by a GC-microwave induced helium plasma detector
A series of alkylthiophenes and dimethyl disulfide were tentatively identified in an oil shale retort gas condensate from a 6-kg bench-scale retort using gas chromatography with a microwave-induced helium plas...
