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At least 1,099 records · Page 61
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Improvement of Design Codes to Account for Accident Thermal Effects on Seismic Performance

This report summarizes the results of experimental and numerical studies conducted to evaluate the effect of accident thermal loads on the seismic response of steel-plate composite (SC) walls and reinforced concrete (RC) walls and beams. The research was sponsored by U.S. Department of Energy through the Nuclear Energy University Program (NEUP), Award Number DE-NE0008256. Summary and conclusions of the research conducted are presented in this report. Based on the observations, analysis and design recommendations for SC and RC structures are also summarized

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2018

Generalized and High-Order Multiscale Finite-Element Methods for Seismic Wave Propagation [Slides]

We have developed a series of multiscale finite-element methods for simulating seismic wave propagation in complex media. The most important feature of multiscale finite-element methods is using medium- and mesh-dependent multiscale basis functions. For different wave equations, or for wave equation modeling in different domains, we design different local spectral/linear problems to compute multiscale basis functions. Multiscale basis functions can accurately capture the fine-scale medium information for coarse-scale modeling problems. Numerical examples have demonstrated the efficiency and accuracy of our multiscale finite-element method framework for wave equation modeling. Future works aim at further improving the efficiency using more levels of information encapsulation, and address more realistic physics problems.

58 GEOSCIENCES↗
DOE OSTI2019

A Traditional Look at SPE Phase 1 Surface Seismic Data: Far-Field Instruments, Measurements, and Analysis

We visually examined surface seismic data from the Source Physics Experiment (SPE) Phase-1 chemical explosions in preparation for waveform analysis and interpretation. Recording stations included far-field (near source) geophone lines, and both permanent network, reoccupied USArray, and temporary stations at local and regional distances. We found that near-source waveforms are dominated by broad band compressional (P), and band limited surface wave (Rg) (< 10 Hz) phases. Distinct, consistent shear (S) phases are difficult to observe visually even with a comprehensive bank of frequency bands. Secondary phases are indistinct at near-local distances, unlike for earthquake sources, especially at the high frequencies of interest for discrimination (e.g. 4-8 Hz), likely due to intense near surface scattering. S phases begin to emerge from the scattered background at and beyond 100 km. We identified regional Pn, Pg and Lg phases to 446 km for SPE-5. The data set is, unfortunately, plagued by poorly recorded instrument responses, or, possibly, time varying site amplification due to human interaction with sensors. Instrument response issues should be fixable, and this should be attempted to make this a truly, high-quality data set for use by the monitoring community.

58 GEOSCIENCES↗
DOE OSTI2019

Seismic Moment Tensor Screening on the Hypersphere

Source type screening based on the seismic moment tensor is investigated on the hypersphere, specifically the 5-sphere S 5 of 6-degree unit vectors representing the normalized symmetric moment tensor. The sample of moment tensors from an explosion dataset is unimodal in S 5 and can be parameterized by the von Mises - Fisher distribution. Screening is then framed using the confidence region of the explosion population mean unit vector. A conservative screen using the 99.9% confidence region is proposed such that an event with an angle on the hypersphere greater than 30.57° from the mean unit moment tensor is screened out. We apply the screen to the September 2017 DPRK explosion and subsequent collapse, and show that the collapse screens out.

58 GEOSCIENCES↗
DOE OSTI2019

Paraniso 1.0: 3-D Full Waveform Seismic Simulation in General Anisotropic Media

Many geologic materials and minerals are seismically anisotropic, with the most general anisotropic material having up to 21 independent elastic coefficients. This report outlines the development of a 3-D, generally anisotropic, linear elastic full waveform finite-difference solver. First, a mathematical description of the solution equations will be described. The finite-difference implementation of these equations will then be shown. Finally, a comparison of results from this new solver to other solutions will be provided as verification that the new algorithm can accurately replicate these solutions.

58 GEOSCIENCES↗
DOE OSTI2016

Geospatial-Temporal Semantic Graph Evaluation for Induced Seismicity Analysis

We assess how geospatial-temporal semantic graphs and our GeoGraphy code implementation might contribute to induced seismicity analysis. We focus on evaluating strengths and weaknesses of both 1) the fundamental concept of semantic graphs and 2) our current code implementation. With extensions and research effort, code implementation limitations can be overcome. The paper also describes relevance including possible data input types, expected analytical outcomes and how it can pair with other approaches and fit into a workflow.

58 GEOSCIENCES↗
DOE OSTI2020

Evaluation the Geotech GS-13BH Borehole Seismic Sensor

Sandia National Laboratories has tested and evaluated the Geotech GS-13BH borehole sensor. The sensor provides a response similar to that of the standard GS-13 short-period seismic sensor intended for pier-installations in a borehole package. The purpose of this seismometer evaluation was to determine a measured sensitivity, amplitude and phase response, self-noise and dynamic range, passband and acceleration response of its calibration coil.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Synthesis of Seismic Methods in Southern Kansas (Milestone G)

We proposed to conduct the following activities in Budget Period 2 with respect to Task 2.1 of the overall project management plan: 1) Local SWS using microseismicity catalog. 2) Continuation of VSM analysis. 3) Synthesis of seismic data and uncertainty analyses. Milestone G: Apply ANT, VSM, and SWS methods to Kansas microseismicity catalog. Calculate 3D model and moment tensor elements and meet milestone E.

58 GEOSCIENCES↗
DOE OSTI2019

Pobabilistic Seismic Hazards Update for LLNL: PSHA Results Report

This document contains a summary of the results from the 2016 LLNL Probabilistic Seismic Hazards Analysis (PSHA) prepared as part of the 10- year Natural Phenomena Hazards (NPH) assessment of Building 332. Revision 3 adds Foundation Input Response Spectra (FIRS) for Increment 3.

58 GEOSCIENCES↗
DOE OSTI2020

Time-Lapse Vertical Seismic Profiling (VSP) for CO 2 Storage in a Depleted Oil Field in Northern Michigan

The goal of the Dover 33 VSP study was to test the effectiveness of time-lapse VSP for detecting and delineating a plume of more than 271,000 tonnes of CO 2 injected into the Brown Niagaran and A-1 Carbonate formations within the Dover 33 reef between March 2013 and September 2016. Five 2D walkaway VSP (WVSP) source lines were acquired by SIGMA3 in September 2016 to investigate the possible time-lapse response in both P-wave and PS-wave seismic data. The data was compared to the same survey geometry acquired in March 2013 by SR2020.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

An efficient method to estimate the probability density of seismic Green's functions

We present a computationally efficient method to approximate the probability distribution of seismic Green's functions given the uncertainty of an Earth model. The method is based on the Karhunen-Loève (KL) theorem and an approximation of the Green's function (or seismogram) covariance. Using Monte Carlo (MC) simulations as a control case, we demonstrate that our KL-based method can accurately reproduce a probability distribution of seismograms that results from an uncertain Earth model for a MC-derived seismogram covariance. We then describe a method to estimate the covariance of the seismograms resulting from those Earth models that is not based on MC simulations. We use the estimated Green's function covariance in conjunction with our KL-based method to produce a Green's function probability distribution, and compare that distribution to a Green's function probability distribution produced using a MC finite difference method. We find that the Green's function probability distribution approximated using our KL-based method generally mimics that produced using the MC simulations, especially for direct-arriving body waves. However the accuracy of the KL-based method generally decreases for later times in the simulated Green's function distribution.

58 GEOSCIENCES↗
DOE OSTI2021

Seismic Shake Table Test Plan

This report is a preliminary test plan of the seismic shake table test. The final report will be developed when all decisions regarding the test hardware, instrumentation, and shake table inputs are made. A new revision of this report will be issued in spring of 2022. The preliminary test plan documents the free-field ground motions that will be used as inputs to the shake table, the test hardware, and instrumentation. It also describes the facility at which the test will take place in late summer of 2022.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Applications of seismic threshold monitoring at an Antarctic glacier [Slides]

Geophysical waveforms collected from Arctic regions provides data required for monitoring global security targets. Some seismic instruments deployed on Scandinavian and Greenlandic sites provide waveform data, but these installations include specific challenges: Sea ice and glacial ice generates waveform interference; Meltwater generates narrowband interference, resembling tonal noise.

58 GEOSCIENCES↗
DOE OSTI2022

Updated Seismic Shake Table Test Plan

This report documents the updated seismic shake table test plan. The report describes the shake table inputs (ground motions), test hardware, shake table facility, friction experiment, and proposed instrumentation.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Constraining induced seismicity hazard on the Neck of the Desert fault for the proposed Iron Mountain, Utah carbon sequestration project

As significantly more focus is placed on carbon sequestration as a means to help mitigate the progression of climate change, the need to adequately characterize an injection target for its induced seismicity potential becomes more apparent. In the Iron Mountain project in Southern Utah, a single fault is identified in the Neck of the Desert near Iron Mountain. The dip of the fault is unknown, and the geomechanical stability of the fault (i.e., distribution of Coulomb failure functions (CFFs)) is highly dependent upon the dip. For some dips, such as 15 degrees, the hazard from injection is low. For other dips, such as 75 degrees, the hazard is high. Another key consideration is the depth of penetration of the fault. Should the fault not penetrate the stress and pressure perturbed region from injection, it will not be induced to fail. Thus, understanding the dip and the depth of penetration of the fault will greatly improve our understanding of the likelihood of inducing an earthquake.

58 GEOSCIENCES↗