Geology topics

J. W. Baker

Publications and source records attributed to J. W. Baker.

4 recordsLinked to original sources

USGS2022

Preliminary national-scale seismic risk assessment of natural gas pipelines in the United States

Although the gas pipeline infrastructure in the United States is vulnerable to the seismic hazards of (i) strong ground shaking, and (ii) ground failures induced by surface faulting, liquefaction, or landslides, limited national guidance exists for operators to consistently evaluate the earthquake response of their pipelines. To provide additional information for stakeholders and establish more consistency at a national scale, we attempt to quantify seismic risk for gas transmission pipelines in the conterminous United States using a metric such as average annual loss, which helps readily distinguish geographic areas of high and low relative risk. Specifically, we integrate the 2018 National Pipeline Mapping System, the 2018 National Seismic Hazard Model, and several candidate models from the literature for estimating pipeline damage. Through this effort, we highlight major research needs for ultimately reducing the many uncertainties associated with a comprehensive seismic risk assessment of gas pipelines.

conterminous United States↗

USGS2022

Open-source resources help navigate new IM regulations

The revision of federal safety regulations for integrity management of gas transmission pipelines to require explicit consideration of seismicity increases the importance for operators to be actively identifying high-consequence areas (HCAs), evaluating seismic-related threats, and choosing a risk model to support risk management decisions. To ensure equal access to information by both operators and inspectors, the authors have compiled publicly available data and tools for practical seismic risk assessments, such as Microsoft building footprints, the USGS National Seismic Hazard Models, and the USGS Ground Failure product.

Oil & Gas Journal↗

USGS2020

Selecting three components of ground motions from Conditional Spectra for multiple stripe analyses

For complex structures where the seismic response depends appreciably on the vertical (V) component of ground motion (GM) (e.g., base-isolated buildings, long-span bridges, dams, nuclear power plants), incremental dynamic analysis (IDA) is commonly utilized to estimate seismic risk, where the V components of GM are selected and scaled based on the corresponding horizontal (H) components. The resulting seismic risk (e.g., fragility estimates, annual rates of failure) will likely be significantly biased when the scale factors in IDA are very large. As an alternative to IDA, multiple stripe analyses (MSA) with GMs for each stripe selected from the Conditional Spectrum (CS) can be used to estimate the seismic risk; however, the V components are still commonly selected and scaled based on the corresponding H components. Consequently, these V components may still be inconsistent relative to the corresponding target hazard, again yielding biased estimates of seismic risk. To improve the accuracy of seismic risk estimates, we extend the CS to include the V component of GM and present an approach to select multicomponent GMs that are hazard consistent with respect to all three components of GM. Using the target and the GM selection approach developed in this study, we then evaluate typical current practice for selecting and scaling V components of GM. We observe that the latter approach can yield hazard-inconsistent multicomponent GMs, but hazard consistency can be improved by including the V component in the selection process, constraining the scale factors, or widening the period range for selecting GMs.

Conference Paper↗

USGS2013

Use of fragile geologic structures as indicators of unexceeded ground motions and direct constraints on probabilistic seismic hazard analysis

We present a quantitative procedure for constraining probabilistic seismic hazard analysis results at a given site, based on the existence of fragile geologic structures at that site. We illustrate this procedure by analyzing precarious rocks and undamaged lithophysae at Yucca Mountain, Nevada. The key metric is the probability that the feature would have survived to the present day, assuming that the hazard results are correct. If the fragile geologic structure has an extremely low probability of having survived (which would be inconsistent with the observed survival of the structure), then the calculations illustrate how much the hazard would have to be reduced to result in a nonnegligible survival probability. The calculations are able to consider structures the predicted failure probabilities of which are a function of one or more ground‐motion parameters, as well as structures that either rapidly or slowly evolved to their current state over time. These calculations are the only way to validate seismic hazard curves over long periods of time.

BSSA↗