Framework for a Ground-Motion Model for Induced Seismic Hazard and Risk Analysis in the Groningen Gas Field, The Netherlands

2017 ◽  
Vol 33 (2) ◽  
pp. 481-498 ◽  
Author(s):  
Julian J. Bommer ◽  
Peter J. Stafford ◽  
Benjamin Edwards ◽  
Bernard Dost ◽  
Ewoud van Dedem ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Quantitative Estimation ◽  
Epistemic Uncertainty ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Small Magnitude ◽  
Ground Motion Model ◽  
Hazard And Risk ◽  
Groningen Gas Field

The potential for building damage and personal injury due to induced earthquakes in the Groningen gas field is being modeled in order to inform risk management decisions. To facilitate the quantitative estimation of the induced seismic hazard and risk, a ground motion prediction model has been developed for response spectral accelerations and duration due to these earthquakes that originate within the reservoir at 3 km depth. The model is consistent with the motions recorded from small-magnitude events and captures the epistemic uncertainty associated with extrapolation to larger magnitudes. In order to reflect the conditions in the field, the model first predicts accelerations at a rock horizon some 800 m below the surface and then convolves these motions with frequency-dependent nonlinear amplification factors assigned to zones across the study area. The variability of the ground motions is modeled in all of its constituent parts at the rock and surface levels.

scholarly journals Ground-motion networks in the Groningen field: usability and consistency of surface recordings

2019 ◽  
Vol 23 (6) ◽  
pp. 1233-1253 ◽  
Author(s):  
Michail Ntinalexis ◽  
Julian J. Bommer ◽  
Elmer Ruigrok ◽  
Benjamin Edwards ◽  
Rui Pinho ◽  
...  
Keyword(s):  
Ground Motion ◽  
Structural Response ◽  
Strong Motion ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Shake Table Tests ◽  
Motion Models ◽  
General Terms ◽  
Hazard And Risk ◽  
Groningen Gas Field

Abstract Several strong-motion networks have been installed in the Groningen gas field in the Netherlands to record ground motions associated with induced earthquakes. There are now more than 450 permanent surface accelerographs plus a mobile array of 450 instruments, which, in addition to many instrumented boreholes, yield a wealth of data. The database of recordings has been of fundamental importance to the development of ground-motion models that form a key element of the seismic hazard and risk estimations for the field. In order to maximise the benefit that can be derived from these recordings, this study evaluates the usability of the recordings from the different networks, in general terms and specifically with regards to the frequency ranges with acceptable signal-to-noise ratios. The study also explores the consistency among the recordings from the different networks, highlighting in particular how a configuration error was identified and resolved. The largest accelerograph network consists of instruments housed in buildings around the field, frequently installed on the lower parts of walls rather than on the floor. A series of experiments were conducted, using additional instruments installed adjacent to these buildings and replicating the installation configuration in full-scale shake table tests, to identify the degree to which structural response contaminated the recordings. The general finding of these efforts was that for PGV and oscillator periods above 0.1 s, the response spectral ordinates from these recordings can be used with confidence.

Ground-Motion Attenuation, Stress Drop, and Directivity of Induced Events in the Groningen Gas Field by Spectral Inversion of Borehole Records

2020 ◽  
Vol 110 (5) ◽  
pp. 2077-2094 ◽  
Author(s):  
Gabriele Ameri ◽  
Christophe Martin ◽  
Adrien Oth
Keyword(s):  
Ground Motion ◽  
Destructive Interference ◽  
Rupture Directivity ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Small Magnitude ◽  
Ground Motion Variability ◽  
Short Period ◽  
Groningen Gas Field ◽  
The Impact

ABSTRACT Production-induced earthquakes in the Groningen gas field caused damage to buildings and concerns for the population, the gas-field owner, and the local and national authorities and institutions. The largest event (ML=3.6) occurred in 2012 near Huizinge, and, despite the subsequent decision of the Dutch government to reduce the gas production in the following years, similar magnitude events occurred in 2018 and 2019 (ML=3.4). Thanks to the improvement of the local seismic networks in the last years, recent events provide a large number of recordings and an unprecedented opportunity to study the characteristics of induced earthquakes in the Groningen gas field and related ground motions. In this study, we exploit the S-wave Fourier amplitude spectra recorded by the 200 m depth borehole sensors of the G network from 2015 to 2019 to derive source and attenuation parameters for ML≥2 induced earthquakes. The borehole spectra are decomposed into source, attenuation, and site nonparametric functions, and parametric models are then adopted to determine moment magnitudes, corner frequencies, and stress drops of 21 events. Attenuation and source parameters are discussed and compared with previous estimates for the region. The impact of destructive interference of upgoing and downgoing waves at borehole depth on the derived parameters is also discussed and assessed to be minor. The analysis of the apparent source spectra reveals that several events show rupture directivity and provides clear observations of frequency-dependent directivity effects in induced earthquakes. The estimated rupture direction shows a good agreement with orientation of pre-existing faults within the reservoir. Our results confirm that rupture directivity is still an important factor for small-magnitude induced events, affecting the amplitude of recorded short-period response spectra and causing relevant spatial ground-motion variability.

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.

scholarly journals A Non-Ergodic Effective Amplitude Ground-Motion Model for California

2021 ◽  
Author(s):  
Grigorios Lavrentiadis ◽  
Norman A. Abrahamson ◽  
Nicolas M. Kuehn
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Amplitude Spectrum ◽  
Time History ◽  
Motion Model ◽  
Small Magnitude ◽  
Varying Coefficients ◽  
Ground Motion Model ◽  
Systematic Effects

Abstract A new non-ergodic ground-motion model (GMM) for effective amplitude spectral (EAS) values for California is presented in this study. EAS, which is defined in Goulet et al. (2018), is a smoothed rotation-independent Fourier amplitude spectrum of the two horizontal components of an acceleration time history. The main motivation for developing a non-ergodic EAS GMM, rather than a spectral acceleration GMM, is that the scaling of EAS does not depend on spectral shape, and therefore, the more frequent small magnitude events can be used in the estimation of the non-ergodic terms. The model is developed using the California subset of the NGAWest2 dataset Ancheta et al. (2013). The Bayless and Abrahamson (2019b) (BA18) ergodic EAS GMM was used as backbone to constrain the average source, path, and site scaling. The non-ergodic GMM is formulated as a Bayesian hierarchical model: the non-ergodic source and site terms are modeled as spatially varying coefficients following the approach of Landwehr et al. (2016), and the non-ergodic path effects are captured by the cell-specific anelastic attenuation attenuation following the approach of Dawood and Rodriguez-Marek (2013). Close to stations and past events, the mean values of the non-ergodic terms deviate from zero to capture the systematic effects and their epistemic uncertainty is small. In areas with sparse data, the epistemic uncertainty of the non-ergodic terms is large, as the systematic effects cannot be determined. The non-ergodic total aleatory standard deviation is approximately 30 to 40% smaller than the total aleatory standard deviation of BA18. This reduction in the aleatory variability has a significant impact on hazard calculations at large return periods. The epistemic uncertainty of the ground motion predictions is small in areas close to stations and past event.

Statistical mechanics-based forecasting of induced seismicity within the Groningen gas field

2020 ◽  
Author(s):  
Stephen Bourne ◽  
Steve Oates
Keyword(s):  
Size Distribution ◽  
Induced Seismicity ◽  
Gas Production ◽  
Linear Functions ◽  
Fault System ◽  
Induced Earthquakes ◽  
Gas Field ◽  
Hazard And Risk ◽  
Stress Dependent ◽  
Groningen Gas Field

<p>Geological faults may fail and produce earthquakes due to external stresses induced by hydrocarbon recovery, geothermal extraction, CO<sub>2</sub> storage or subsurface energy storage. The associated hazard and risk critically depend on the spatiotemporal and size distribution of any induced seismicity. The observed statistics of induced seismicity within the Groningen gas field evolve as non-linear functions of the poroelastic stresses generated by pore pressure depletion since 1965. The rate of earthquake initiation per unit stress has systematically increased as an exponential-like function of cumulative incremental stress over at least the last 25 years of gas production. The expected size of these earthquakes also increased in a manner consistent with a stress-dependent tapering of the seismic moment power-law distribution. Aftershocks of these induced earthquakes are also observed, although evidence for any stress-dependent aftershock productivity or spatiotemporal clustering is inconclusive.</p><p>These observations are consistent with the reactivation of a mechanically disordered fault system characterized by a large, stochastic prestress distribution. If this prestress variability significantly exceeds the induced stress loads, as well as the earthquake stress drops, then the space-time-size distribution of induced earthquakes may be described by mean field theories within statistical fracture mechanics. A probabilistic seismological model based on these theories matches the history of induced seismicity within the Groningen region and correctly forecasts the seismicity response to reduced gas production rates designed to lower the associated seismic hazard and risk.</p>

Re-thinking site amplification in regional seismic risk assessment

2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 274-297 ◽  
Author(s):  
Graeme Weatherill ◽  
Sreeram Reddy Kotha ◽  
Fabrice Cotton
Keyword(s):  
Risk Assessment ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Regional Scale ◽  
Site Amplification ◽  
Direct Function ◽  
Motion Models ◽  
Topographic Slope ◽  
Ground Motion Model ◽  
Hazard And Risk

Probabilistic assessment of seismic hazard and risk over a geographical region presents the modeler with challenges in the characterization of the site amplification that are not present in site-specific assessment. Using site-to-site residuals from a ground motion model fit to observations from the Japanese KiK-net database, correlations between measured local amplifications and mappable proxies such as topographic slope and geology are explored. These are used subsequently to develop empirical models describing amplification as a direct function of slope, conditional upon geological period. These correlations also demonstrate the limitations of inferring 30-m shearwave velocity from slope and applying them directly into ground motion models. Instead, they illustrate the feasibility of deriving spectral acceleration amplification factors directly from sets of observed records, which are calibrated to parameters that can be mapped uniformly on a regional scale. The result is a geologically calibrated amplification model that can be incorporated into national and regional seismic hazard and risk assessment, ensuring that the corresponding total aleatory variability reflects the predictive capability of the mapped site proxy.

scholarly journals A Non-ergodic Spectral Acceleration Ground Motion Model for California Developed with Random Vibration Theory

2021 ◽  
Author(s):  
Grigorios Lavrentiadis ◽  
Norman A. Abrahamson
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Random Vibration ◽  
Epistemic Uncertainty ◽  
Response Spectrum ◽  
Motion Model ◽  
Small Magnitude ◽  
Vibration Theory ◽  
Ground Motion Model ◽  
Random Vibration Theory

Abstract A new approach for creating a non-ergodic PSA ground-motion model (GMM) is presented which account for the magnitude dependence of the non-ergodic effects. In this approach, the average PSA scaling is controlled by an ergodic PSA GMM, and the non-ergodic effects are captured with non-ergodic PSA factors, which are the adjustment that needs to be applied to an ergodic PSA GMM to incorporate the non-ergodic effects. The non-ergodic PSA factors are based on EAS non-ergodic effects and are converted to PSA through Random Vibration Theory (RVT). The advantage of this approach is that it better captures the non-ergodic source, path, and site effects through the small magnitude earthquakes. Due to the linear properties of Fourier Transform, the EAS non-ergodic effects of the small events can be applied directly to the large magnitude events. This is not the case for PSA, as response spectrum is controlled by a range of frequencies, making PSA non-ergodic effects depended on the spectral shape which is magnitude dependent. Two PSA non-ergodic GMMs are derived using the ASK14 (Abrahamson et al., 2014) and CY14 (Chiou and Youngs, 2014) GMMs as backbone models, respectively. The non-ergodic EAS effects are estimated with the LAK21 (Lavrentiadis et al., In press) GMM. The RVT calculations are performed with the V75 (Vanmarcke, 1975) peak factor model, the Da0.05−0.85 estimate of AS96 (Abrahamson and Silva, 1996) for the ground-motion duration, and BT15 (Boore and Thompson, 2015) oscillator-duration model. The California subset of the NGAWest2 database (Ancheta et al., 2014) is used for both models. The total aleatory standard deviation of the two non-ergodic PSA GMMs is approximately 30 to 35% smaller than the total aleatory standard deviation of the corresponding ergodic PSA GMMs. This reduction has a significant impact on hazard calculations at large return periods. In remote areas, far from stations and past events, the reduction of aleatory variability is accompanied by an increase of epistemic uncertainty.

Non-ergodic FAS Ground-Motion Model for France

2020 ◽  
Author(s):  
Chih Hsuan Sung ◽  
Norman Abrahamson ◽  
Nicolas Kuehn ◽  
Paola Traversa ◽  
Irmela Zentner
Keyword(s):  
Standard Deviation ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Geographical Location ◽  
Gaussian Process Regression ◽  
Motion Model ◽  
Data Set ◽  
Small Magnitude ◽  
Ground Motion Model ◽  
Anelastic Attenuation

<p>In this study, we use an ergodic ground motion model (GMM) of California of Bayless and Abrahamson (2019) as a backbone and incorporate the varying-coefficient model (VCM) to develop a new French non-ergodic GMM based on the French RESIF data set (1996-2016). Most of the magnitudes of this database are small (Mw = 2.0 – 5.2), so we adopt the Fourier amplitude spectral GMM rather than the spectral acceleration model, which allows the use of small magnitude data to constrain path and site effects without the complication of the scaling being affected by differences in the response spectral shape. For the VCM, the coefficients of GMPE can vary by geographical location and they are estimated using Gaussian process regression. That is, 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. Moreover, the epistemic uncertainty associated with the predicted ground motions also varies spatially: it is small in locations where there are many events or stations and it is large in sparse data regions. Finally, we modify the anelastic attenuation term of a GMM by the cell-specific approach of Kuehn et al. (2019) to allow for azimuth-dependent attenuation for each source which reduces the standard deviation of residuals at long distances. The results show that combining the above two methods (VCM & cell-specific) to lead an aleatory standard deviation of residuals for the GMM that is reduced by ~ 47%, which can have huge implications for seismic-hazard calculations.</p>

scholarly journals Simulations for the development of a ground motion model for induced seismicity in the Groningen gas field, The Netherlands

2018 ◽  
Vol 17 (8) ◽  
pp. 4441-4456 ◽  
Author(s):  
B. Edwards ◽  
B. Zurek ◽  
E. van Dedem ◽  
P. J. Stafford ◽  
S. Oates ◽  
...  
Keyword(s):  
The Netherlands ◽  
Ground Motion ◽  
Induced Seismicity ◽  
Motion Model ◽  
Gas Field ◽  
Ground Motion Model ◽  
Groningen Gas Field

scholarly journals A ground motion logic tree for seismic hazard analysis in the stable cratonic region of Europe: regionalisation, model selection and development of a scaled backbone approach

2020 ◽  
Vol 18 (14) ◽  
pp. 6119-6148
Author(s):  
Graeme Weatherill ◽  
Fabrice Cotton
Keyword(s):  
United States ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Epistemic Uncertainty ◽  
Hazard Analysis ◽  
Seismic Hazard Analysis ◽  
Eastern United States ◽  
Logic Tree ◽  
Short Period ◽  
Northeastern Europe

Abstract Regions of low seismicity present a particular challenge for probabilistic seismic hazard analysis when identifying suitable ground motion models (GMMs) and quantifying their epistemic uncertainty. The 2020 European Seismic Hazard Model adopts a scaled backbone approach to characterise this uncertainty for shallow seismicity in Europe, incorporating region-to-region source and attenuation variability based on European strong motion data. This approach, however, may not be suited to stable cratonic region of northeastern Europe (encompassing Finland, Sweden and the Baltic countries), where exploration of various global geophysical datasets reveals that its crustal properties are distinctly different from the rest of Europe, and are instead more closely represented by those of the Central and Eastern United States. Building upon the suite of models developed by the recent NGA East project, we construct a new scaled backbone ground motion model and calibrate its corresponding epistemic uncertainties. The resulting logic tree is shown to provide comparable hazard outcomes to the epistemic uncertainty modelling strategy adopted for the Eastern United States, despite the different approaches taken. Comparison with previous GMM selections for northeastern Europe, however, highlights key differences in short period accelerations resulting from new assumptions regarding the characteristics of the reference rock and its influence on site amplification.

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