Time-dependent seismic hazard and risk due to wastewater injection in Oklahoma

2021 ◽  
pp. 875529302098802
Author(s):  
Iason Grigoratos ◽  
Paolo Bazzurro ◽  
Ellen Rathje ◽  
Alexandros Savvaidis
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Risk ◽  
Risk Model ◽  
Time Dependent ◽  
Economic Losses ◽  
Motion Model ◽  
Seismicity Rate ◽  
Ground Motion Model ◽  
Seismicity Rates

In the past decade, Oklahoma has experienced unprecedented seismicity rates, following an increase in the volumes of wastewater that are being disposed underground. In this article, we perform a probabilistic assessment of the time-dependent seismic hazard in Oklahoma and incorporate these results into an integrated seismic risk model to assess the evolution of the statewide economic losses, including a conservative forecast through 2030. Our risk model employs an injection-driven earthquake rate model, a region-specific ground motion model, a recent Vs30 map, HAZUS exposure data and updated vulnerability curves for both structural and nonstructural elements, and contents. The calculations are performed using a stochastic Monte Carlo–based approach implemented in the OpenQuake engine. The resulting seismic hazard maps illustrate the incompatibility of the regional seismic provisions with the current seismicity. In 2015, in particular, the induced seismic hazard in several places in Oklahoma was higher than along the San Andreas fault. During the peak of seismicity in 2015, the seismic risk was 275 times higher than the background level, with the vast majority of losses originating from damages to nonstructural elements and contents. Our direct economic loss estimates are in reasonable agreement with the paid insurance claims, but show significant sensitivity to the ground motion model selection. The proposed risk model, with possible regular updates on the seismicity rate forecast, can help stakeholders define acceptable production levels.

Probabilistic seismic risk assessment of India

2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 345-371
Author(s):  
Anirudh Rao ◽  
Debashish Dutta ◽  
Pratim Kalita ◽  
Nick Ackerley ◽  
Vitor Silva ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Risk ◽  
Risk Model ◽  
Building Design ◽  
Design Guidelines ◽  
Exposure Model ◽  
Economic Losses ◽  
Exceedance Probability ◽  
Earthquake Risk ◽  
Earthquake Insurance

This study presents a comprehensive open probabilistic seismic risk model for India. The proposed model comprises a nationwide residential and non-residential building exposure model, a selection of analytical seismic vulnerability functions tailored for Indian building classes, and the open implementation of an existing probabilistic seismic hazard model for India. The vulnerability of the building exposure is combined with the seismic hazard using the stochastic (Monte Carlo) event-based calculator of the OpenQuake engine to estimate probabilistic seismic risk metrics such as average annual economic losses and the exceedance probability curves at the national, state, district, and subdistrict levels. The risk model and the underlying datasets, along with the risk metrics calculated at different scales, are intended to be used as tools to quantitatively assess the earthquake risk across India and also compare with other countries to develop risk-informed building design guidelines, for more careful land-use planning, to optimize earthquake insurance pricing, and to enhance general earthquake risk awareness and preparedness.

A Ground-Motion Logic-Tree Scheme for Regional Seismic Hazard Studies

2017 ◽  
Vol 33 (3) ◽  
pp. 837-856 ◽  
Author(s):  
Özkan Kale ◽  
Sinan Akkar
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Motion Prediction ◽  
Motion Model ◽  
Ground Motion Prediction Equations ◽  
Ground Motion Prediction ◽  
Logic Tree ◽  
Ground Motion Model ◽  
The One

We propose a methodology that can be useful to the hazard expert in building ground-motion logic trees to capture the center and range of ground-motion amplitudes. The methodology can be used to identify a logic-tree structure and weighting scheme that prevents the dominancy of a specific ground-motion model. This strategy can be useful for regional probabilistic seismic hazard since logic-trees biased by a specific ground-motion predictive model (GMPE) may cause disparities in the seismic hazard for regions represented by large number of sites with complex seismic features. The methodology first identifies a suit of candidate ground-motion prediction equations that can cover the center, body and range of estimated ground motions. The GMPE set is then used for establishing alternative logic-trees composed of different weighting schemes to identify the one(s) that would not be biased towards a particular GMPE due to its sensitivity to the weights. The proposed methodology utilizes visual and statistical tools to assess the ground motion distributions over large areas that makes it more practical for regional hazard studies.

scholarly journals Hazard-consistent seismic losses and collapse capacities for light-frame wood buildings in California and Cascadia

2021 ◽  
Author(s):  
Robert E. Chase ◽  
Abbie B. Liel ◽  
Nicolas Luco ◽  
Zach Bullock
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Risk ◽  
Ground Motions ◽  
Spectral Shape ◽  
Economic Losses ◽  
Frequency Content ◽  
Crustal Earthquakes ◽  
Design Values ◽  
American Society

AbstractWe evaluate the seismic performance of modern seismically designed wood light-frame (WLF) buildings, considering regional seismic hazard characteristics that influence ground motion duration and frequency content and, thus, seismic risk. Results show that WLF building response correlates strongly with ground motion spectral shape but weakly with duration. Due to the flatter spectral shape of ground motions from subduction events, WLF buildings at sites affected by these earthquakes may experience double the economic losses for a given intensity of shaking, and collapse capacities may be reduced by up to 50%, compared to those at sites affected by crustal earthquakes. These differences could motivate significant increases in design values at sites affected by subduction earthquakes to achieve the uniform risk targets of the American Society of Civil Engineers (ASCE) 7 standard.

Probabilistic Seismic Hazard Analysis Based on Arias Intensity in the North–South Seismic Belt of China

2021 ◽  
Author(s):  
Li Xuejing ◽  
Weijin Xu ◽  
Mengtan Gao
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Probabilistic Seismic Hazard ◽  
Motion Model ◽  
Seismic Belt ◽  
Arias Intensity ◽  
The North ◽  
Ground Motion Model

ABSTRACT Arias intensity (IA), as an important seismic parameter, which contains the information of amplitude, frequencies, and duration of ground motion, plays a crucial role in characterizing seismic hazard such as earthquake-induced landslides. In this article, we conducted probabilistic seismic hazard analysis (PSHA) based on IA in China’s north–south seismic belt. We adopted the seismic sources and seismicity parameters used in the fifth generation of the Seismic Ground Motion Parameter Zoning Map of China, and two ground-motion model of IA. The results show that the values of IA are greater than 0.11 m/s in most regions of the north–south seismic belt. The provincial capital cities and most prefecture-level cities in the seismic zone are located in the region with IA-values greater than 0.32 m/s. The values of IA are above 0.54 m/s in the region around the main fault zone. This means that the north–south seismic belt is prone to extremely high-seismic hazard, particularly earthquake-induced landslides. Therefore, it is important to strengthen the evaluation and prevention of earthquake-induced landslides in this area. As we have found significant differences in the values of IA calculated from different ground-motion model, it is necessary to study the ground-motion model of IA for the western geological environment of China. In addition, the PSHA based on IA gives more consideration to the influence of large earthquakes than that based on peak ground acceleration. Therefore, IA plays an important role in seismic design of major engineering projects. The results of this article are of great scientific significance for understanding the seismic hazard of the north–south seismic belt.

Seismic risk assessment for the CEUS nuclear power plant fleet based on the NGA-East ground motion model

2021 ◽  
pp. 875529302110246
Author(s):  
Mohamed M Talaat ◽  
Timothy J Graf ◽  
Abhinav Anup ◽  
Gregory S Hardy ◽  
John M Richards
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Nuclear Power ◽  
Assessment Tools ◽  
Specific Information ◽  
Valuable Insight ◽  
Motion Model ◽  
Ground Motion Model

Knowledge of seismic hazard at engineered facilities evolves with the growth in related technical fields. This presents challenges to stability and decision-making concerning safety that require effective assessment tools. Updated mean hazard estimates were developed at nuclear power plant (NPP) sites in Central and Eastern United States (CEUS) using the Next Generation Attenuation (NGA)-East ground motion model (GMM) and the latest available site amplification data. These estimates indicated that seismic hazard increases at several CEUS NPP sites, especially for spectral frequencies below 5 Hz. To assess the safety implications, updated mean seismic core damage frequency (SCDF) estimates were developed for the CEUS NPP fleet using the updated mean hazard estimates and updated plant-level fragilities (PLFs). The PLFs were developed from plant-specific information compiled by the U.S. Nuclear Regulatory Commission (USNRC) and recent seismic probabilistic risk assessments (SPRAs) completed by some NPPs. The SCDF quantification followed a method defined by the USNRC to combine risk contributions from different spectral frequencies. While not intended to provide a precise quantification of risk, such as that provided by a full SPRA, when the results are compared against other estimates using the same approach, this process provides valuable insight into the overall change in risk as the understanding of hazard changes. The assessment indicated no significant change in estimated risk for the majority of the CEUS fleet compared to the 2010 USNRC estimates—about 90% of the fleet risk distribution was lower, equal, or slightly higher. A few NPPs had SCDF estimates significantly larger than the 2010 estimates. The SCDF increases at these few NPPs have larger contributions from updated PLFs than updated hazard estimates. The majority of these NPPs have recently completed detailed SPRAs and have tools to develop more accurate estimates of the updated risk than can be achieved in this fleet-level study.

Simplified methods to estimate mean hazard due to updated ground motion model: Application to nuclear power plants in CEUS

2021 ◽  
pp. 875529302110074
Author(s):  
Mohamed M Talaat ◽  
Andrew Seifried ◽  
Abhinav Anup ◽  
Gregory S Hardy ◽  
John M Richards
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Nuclear Power ◽  
Power Plants ◽  
Site Response ◽  
Motion Model ◽  
Eastern United States ◽  
Logic Tree ◽  
Ground Motion Model ◽  
Good Agreement

Two methods were developed to estimate updated mean seismic hazard for existing probabilistic seismic hazard analyses (PSHAs) due to a change in the ground motion model (GMM). Both methods were used to estimate updated hazard at nuclear power plant (NPP) sites in the Central and Eastern United States (CEUS) for a change from the Electric Power Research Institute (EPRI) 2013 GMM to the Next Generation Attenuation (NGA)-East GMM. These methods present efficient tools to inform decisions on whether to perform a full PSHA revision or other detailed evaluations, especially when a large number of sites must be analyzed. A Simplified Hazard (SiHaz) method was developed to estimate mean hazard explicitly using a reduced PSHA logic tree that incorporates the updated GMM and potential changes in the site response model. An alternative scaling method was independently developed to be applied directly to current CEUS NPP hazard. Both methods were validated using updated PSHA results at several sites. Estimates at 46 NPP sites using both methods showed good agreement for mean annual frequencies of exceedance between 1E-4 and 1E-5/yr.

scholarly journals A Non-Ergodic Ground-Motion Model of Fourier Amplitude Spectra for France

2021 ◽  
Author(s):  
Chih-Hsuan Sung ◽  
Norman Abrahamson ◽  
Nicolas M. Kuehn ◽  
Paola Traversa ◽  
Irmela Zentner
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Skewed Distribution ◽  
Motion Model ◽  
Data Set ◽  
Small Magnitude ◽  
Ground Motion Model ◽  
The Mean ◽  
Hazard Level

Abstract We used an ergodic ground-motion model (GMM) of California of Bayless and Abrahamson (Bull Seismol Soc Am 109(5):2088–2105, 2019) as a backbone model and incorporated the varying-coefficient model (VCM), with a modification for anisotropic path effects, to develop a new non-ergodic GMM for France based on the French RESIF data set (1996-2016). Most of the earthquakes in this database have small-to-moderate magnitudes (M2.0 – M5.2). We developed the GMM for the smoothed effective amplitude spectrum (EAS) rather than for elastic spectral acceleration because it allows the use of small magnitude data to constrain linear effects of the path and site without the complication of the scaling being affected by differences in the response spectral shape. For the VCM, the coefficients of GMM can vary by geographical location and they are estimated using Gaussian-process regression. There is a separate set of coefficients for each source and site coordinate, including both the mean coefficients and the epistemic uncertainty in the coefficients. We further modify the anelastic attenuation term of a GMM by the cell-specific approach of Kuehn et al. (Bull Seismol Soc Am 109 (2): 575–585, 2019) to allow for azimuth-dependent attenuation for each source which reduces the standard deviation of the residuals at long distances. As an example, we compute the 5Hz seismic hazard for two sites using the non-ergodic EAS GMM. At the 1 10-4 annual frequency of exceedance hazard level, there can be a large difference between the ergodic hazard and the non-ergodic hazard if the site is close to the available data. The combination of the non-ergodic median ground motion and the reduced aleatory variability can have large implications for seismic-hazard estimation for long return periods. For some sites, the estimated hazard will increase and for other sites the estimated hazard will decrease compared to the traditional ergodic GMM approach. Due to the skewed distribution of the epistemic uncertainty of the hazard, more of the sites will see a decrease in the mean hazard mean hazard at the 1 10-4 hazard level than will see an increase as a result of using the non-ergodic GMM.

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