scholarly journals A Novel Approach to Assessing Nuisance Risk from Seismicity Induced by UK Shale Gas Development, with Implications for Future Policy Design

2020 ◽  
Author(s):  
Gemma Cremen ◽  
Maximilian J. Werner
Keyword(s):  
Ground Motion ◽  
Shale Gas ◽  
Induced Seismicity ◽  
Structural Damage ◽  
Policy Design ◽  
Risk Mitigation ◽  
Forecast Model ◽  
Ground Shaking ◽  
North West ◽  
Novel Approach

Abstract. We propose a novel framework for assessing the risk associated with seismicity induced from hydraulic fracturing, which has been a notable source of recent public concern. The framework combines statistical forecast models for injection-induced seismicity, ground motion prediction equations, and exposure models for affected areas, to quantitatively link the volume of fluid injected during operations with the potential for nuisance felt ground motions. Such (relatively small) motions are expected to be more aligned with the public tolerance threshold for induced seismicity than larger ground shaking that could cause structural damage. This proactive type of framework, which facilitates control of the injection volume ahead of time for risk mitigation, has significant advantages over reactive-type magnitude and ground motion-based systems typically used for induced seismicity management. The framework is applied to the region surrounding the Preston New Road shale gas site in North West England. A notable finding is that the calculations are particularly sensitive to assumptions of the seismicity forecast model used, i.e. whether it limits the cumulative seismic moment released for a given volume or assumes seismicity is consistent with the Gutenberg–Richter distribution for tectonic events. Finally, we discuss how the framework can be used to inform relevant policy.

scholarly journals A novel approach to assessing nuisance risk from seismicity induced by UK shale gas development, with implications for future policy design

2020 ◽  
Vol 20 (10) ◽  
pp. 2701-2719
Author(s):  
Gemma Cremen ◽  
Maximilian J. Werner
Keyword(s):  
Ground Motion ◽  
Shale Gas ◽  
Induced Seismicity ◽  
Structural Damage ◽  
Policy Design ◽  
Risk Mitigation ◽  
Forecast Model ◽  
Ground Shaking ◽  
North West ◽  
Novel Approach

Abstract. We propose a novel framework for assessing the risk associated with seismicity induced by hydraulic fracturing, which has been a notable source of recent public concern. The framework combines statistical forecast models for injection-induced seismicity, ground motion prediction equations, and exposure models for affected areas, to quantitatively link the volume of fluid injected during operations with the potential for nuisance felt ground motions. Such (relatively small) motions are expected to be more aligned with the public tolerance threshold for induced seismicity than larger ground shaking that could cause structural damage. This proactive type of framework, which facilitates control of the injection volume ahead of time for risk mitigation, has significant advantages over reactive-type magnitude and ground-motion-based systems typically used for induced seismicity management. The framework is applied to the region surrounding the Preston New Road shale gas site in North West England. A notable finding is that the calculations are particularly sensitive to assumptions of the seismicity forecast model used, i.e. whether it limits the cumulative seismic moment released for a given volume or assumes seismicity is consistent with the Gutenberg–Richter distribution for tectonic events. Finally, we discuss how the framework can be used to inform relevant policy.

scholarly journals The 30 October 2020 Samos (Eastern Aegean Sea) Earthquake: effects of source rupture, path and local-site conditions on the observed and simulated ground motions

2021 ◽  
Author(s):  
Aybige Akinci ◽  
Daniele Cheloni ◽  
AHMET ANIL DINDAR
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Ground Motions ◽  
Aegean Sea ◽  
Peak Ground Velocity ◽  
Ground Shaking ◽  
Local Site ◽  
Eastern Aegean ◽  
Motion Characteristics ◽  
Eastern Aegean Sea

Abstract On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately 70 km from the epicenter. In this study, we provide a detailed description of the Samos earthquake, starting from the fault rupture to the ground motion characteristics. We first use Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data to constrain the source mechanisms. Then, we utilize this information to analyze the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and spectral pseudo-accelerations. Modelling of geodetic data shows that the Samos earthquake ruptured a NNE-dipping normal fault located offshore north of Samos, with up to 2.5-3 m of slip and an estimated geodetic moment of 3.3 ⨯ 1019 Nm (MW 7.0). Although low PGA were induced by the earthquake, the ground shaking was strongly amplified in Izmir throughout the alluvial sediments. Structural damage observed in Izmir reveals the potential of seismic risk due to the local site effects. To better understand the earthquake characteristics, we generated and compared stochastic strong ground motions with the observed ground motion parameters as well as the ground motion prediction equations (GMPEs), exploring also the efficacy of the region-specific parameters which may be improved to better predict the expected ground shaking from future large earthquakes in the region.

scholarly journals A New Procedure for Evaluating Ground-Motion Models, with Application to Hydraulic-Fracture-Induced Seismicity in the United Kingdom

2020 ◽  
Vol 110 (5) ◽  
pp. 2380-2397 ◽  
Author(s):  
Gemma Cremen ◽  
Maximilian J. Werner ◽  
Brian Baptie
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Shale Gas ◽  
Hydraulic Fracture ◽  
Induced Seismicity ◽  
Ground Motions ◽  
Induced Earthquakes ◽  
Statistical Tool ◽  
Motion Models ◽  
Ground Motion Models

ABSTRACT An essential component of seismic hazard analysis is the prediction of ground shaking (and its uncertainty), using ground-motion models (GMMs). This article proposes a new method to evaluate (i.e., rank) the suitability of GMMs for modeling ground motions in a given region. The method leverages a statistical tool from sensitivity analysis to quantitatively compare predictions of a GMM with underlying observations. We demonstrate the performance of the proposed method relative to several other popular GMM ranking procedures and highlight its advantages, which include its intuitive scoring system and its ability to account for the hierarchical structure of GMMs. We use the proposed method to evaluate the applicability of several GMMs for modeling ground motions from induced earthquakes due to U.K. shale gas development. The data consist of 195 recordings at hypocentral distances (R) less than 10 km for 29 events with local magnitude (ML) greater than 0 that relate to 2018/2019 hydraulic-fracture operations at the Preston New Road shale gas site in Lancashire and 192 R<10  km recordings for 48 ML>0 events induced—within the same geologic formation—by coal mining near New Ollerton, North Nottinghamshire. We examine: (1) the Akkar, Sandikkaya, and Bommer (2014) models for European seismicity; (2) the Douglas et al. (2013) model for geothermal-induced seismicity; and (3) the Atkinson (2015) model for central and eastern North America induced seismicity. We find the Douglas et al. (2013) model to be the most suitable for almost all of the considered ground-motion intensity measures. We modify this model by recomputing its coefficients in line with the observed data, to further improve its accuracy for future analyses of the seismic hazard of interest. This study both advances the state of the art in GMM evaluation and enhances understanding of the seismic hazard related to U.K. shale gas development.

Evaluation of stratigraphic effects on seismic site response over large areas: the case study of Italy

2021 ◽  
Author(s):  
Gaetano Falcone ◽  
Gianluca Acunzo ◽  
Amerigo Mendicelli ◽  
Federico Mori ◽  
Giuseppe Naso ◽  
...  
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Risk Mitigation ◽  
Site Response ◽  
Free Field ◽  
Response Spectra ◽  
Seismic Intensity ◽  
Site Condition ◽  
Ground Shaking ◽  
Seismic Site Response

<p>Estimation of site effects over large areas is a key-issue for land management and emergency system planning in a risk mitigation perspective. In general, site-conditions are retrieved from available global datasets and the ground-shaking estimation is based on ground motion prediction equations.</p><p>An advanced procedure to estimate site effects over large areas is here proposed with reference to the Italian territory. Site-condition were defined for homogenous morpho-geological areas in accordance to the borehole logs and the geophysical data archived in the Italian database for seismic microzonation (https://www.webms.it/). Ground motion modifications were determined by means of about 30 milion of one-dimensional numerical simulations of local seismic site response. Correlations between amplification factors (i.e. the ratio between free-field and outcrop response spectra), AF, and site-condition (i.e. harmonic mean of the shear wave velocity in the upper 30 m of the deposit, V<sub>S30</sub>) were determined for each morpho-geological homogeneous area depending on the reference seismic intensity (i.e. referred to the outcropping stiff rock characterised by V<sub>S30</sub> ≥ 800 m/s). The AF-V<sub>S30</sub> correlations were proved to satisfactory forecast the site effects when compared with the results of site specific estimation of local seismic site response.</p>

scholarly journals Seismic Hazard and Risk Due to Induced Earthquakes at a Shale Gas Site

2021 ◽  
Author(s):  
Benjamin Edwards ◽  
Helen Crowley ◽  
Rui Pinho ◽  
Julian J. Bommer
Keyword(s):  
United Kingdom ◽  
Ground Motion ◽  
Shale Gas ◽  
Structural Damage ◽  
Nonlinear Dynamic Analysis ◽  
Peak Ground Velocity ◽  
Seismic Risk Analysis ◽  
British Geological Survey ◽  
Waveform Data ◽  
Macroseismic Intensities

ABSTRACT Hydraulic fracturing of the first shale gas well at Preston New Road (PNR), Blackpool, United Kingdom, in late 2018, marked the end of a 7 yr United Kingdom-wide moratorium on fracking. Despite a strict traffic-light system being in place, seismic events up to ML 2.9 were induced. The ML 2.9 event was accompanied by reports of damage and was assigned European Macroseismic Scale 1998 (EMS-98) intensity VI by the British Geological Survey. The moratorium was subsequently reinstated in late 2019. The study here presents a pseudo-probabilistic seismic risk analysis and is applied to the larger of the induced events at PNR, in addition to hypothetical larger events. Initially, site characterization analysis is undertaken using direct and indirect methods. These analyses show low-velocity deposits dominate the region (VS30‾=227  m/s). We test existing ground-motion prediction equations using spatially dependent VS30 to determine applicability to the recorded waveform data and produce a referenced empirical model. Predicting median and 84th percentile peak ground velocity fields, we subsequently determine macroseismic intensities. Epicentral intensities of IV, IV–V, and VI–VII are predicted for the observed ML 2.9, and hypothetical ML 3.5 and 4.5 scenarios, respectively. A probabilistic analysis of damage is performed for 3500 ground-motion realizations (2.1≤ML≤4.5) using the OpenQuake-engine, with nonlinear dynamic analysis undertaken to define building fragility. Based on these analyses, the onset of cosmetic damage (DS1) in terms of median risk is observed for the ML 2.9 event. Mean modeled occurrences of DS1 and DS2 (minor structural damage), 75 and 10 instances, respectively, are consistent with reported damage (DS1:97, DS2:50). Significant occurrences (median≥30 buildings) of DS2, DS3, and DS4 (minor to major structural damage) are likely for ML 3.5, 4.0, and 4.5 events, respectively. However, by comparing reported damage with modeled damage due to the ML 2.9 event and considering the fact that low macroseismic intensities (EMS-98 <4) are often not reported by the public, we conclude that the previously assigned intensity of VI is too high, with V being more appropriate.

scholarly journals A Probabilistic Model to Evaluate Options for Mitigating Induced Seismic Risk

2019 ◽  
Vol 35 (2) ◽  
pp. 537-564 ◽  
Author(s):  
Jan van Elk ◽  
Stephen J. Bourne ◽  
Steve J. Oates ◽  
Julian J. Bommer ◽  
Rui Pinho ◽  
...  
Keyword(s):  
Induced Seismicity ◽  
Production Control ◽  
Risk Model ◽  
Risk Mitigation ◽  
Mitigation Strategies ◽  
Seismic Retrofitting ◽  
Anthropogenic Activity ◽  
Gas Field ◽  
Ground Shaking ◽  
Groningen Gas Field

Common responses to induced seismicity are based on control of the anthropogenic activity causing the earthquakes, such as fluid injection or withdrawal, in order to limit either the magnitudes of the events or the level of ground motion to within established thresholds. An alternative risk-mitigation option is seismic retrofitting of the more vulnerable buildings potentially exposed to the ground shaking to reduce the risk to acceptable levels. Optimal mitigation strategies may combine both production control and structural strengthening, for which a probabilistic risk model is required that can estimate the change in hazard caused by production or injection variations and the changes in fragility resulting from structural interventions. Such a risk model has been developed for the Groningen gas field in the Netherlands. The framework for this risk model to inform decision making regarding mitigation strategies can be adapted to other cases of anthropogenically induced seismicity.

scholarly journals Comparing the Performance of Regional Earthquake Early Warning Algorithms in Europe

2021 ◽  
Vol 9 ◽  
Author(s):  
Elisa Zuccolo ◽  
Gemma Cremen ◽  
Carmine Galasso
Keyword(s):  
Real Time ◽  
Ground Motion ◽  
Early Warning ◽  
Risk Mitigation ◽  
Source Parameters ◽  
Warning System ◽  
Optimal Choice ◽  
Earthquake Early Warning ◽  
Ground Shaking ◽  
Processing Times

Several earthquake early warning (EEW) algorithms have been developed worldwide for rapidly estimating real-time information (i.e., location, magnitude, ground shaking, and/or potential consequences) about ongoing seismic events. This study quantitatively compares the operational performance of two popular regional EEW algorithms for European conditions of seismicity and network configurations. We specifically test PRobabilistic and Evolutionary early warning SysTem (PRESTo) and the implementation of the Virtual Seismologist magnitude component within SeisComP, VS(SC), which we use jointly with the SeisComP scanloc module for locating events. We first evaluate the timeliness and accuracy of the location and magnitude estimates computed by both algorithms in real-time simulation mode, accounting for the continuous streaming of data and effective processing times. Then, we focus on the alert-triggering (decision-making) phase of EEW and investigate both algorithms’ ability to yield accurate ground-motion predictions at the various temporal instances that provide a range of warning times at target sites. We find that the two algorithms show comparable performances in terms of source parameters. In addition, PRESTo produces better rapid estimates of ground motion (i.e., those that facilitate the largest lead times); therefore, we conclude that PRESTo may have a greater risk-mitigation potential than VS(SC) in general. However, VS(SC) is the optimal choice of EEW algorithm if shorter warning times are permissible. The findings of this study can be used to inform current and future implementations of EEW systems in Europe.

scholarly journals Characteristics of the Strong Ground Motion from the 24th August 2016 Amatrice Earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Marta Pischiutta ◽  
Aybige Akinci ◽  
Luca Malagnini ◽  
André Herrero
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Normal Fault ◽  
Peak Ground Velocity ◽  
Rupture Directivity ◽  
Ground Acceleration ◽  
Ground Shaking ◽  
North West ◽  
Motion Characteristics ◽  
2016 Amatrice Earthquake

<em>The 2016 August 24 Amatrice earthquake occurred at 03:36 local time in Central Apennines Italy with an epicentre at 43.36<sup>°</sup>E, 38.76<sup>°</sup>N, Istituto Nazionale di Geofisica e Vulcanologia (INGV), few kilometers north of the city of Amatrice. The earthquake ruptured a North-West (NW)–South-East (SE) oriented normal fault dipping toward the South-West (SW) (Scognamiglio et al., 2016). High values of peak ground acceleration (~0.45 g) were observed close to Amatrice (3 stations being few kilometer distances from the fault). The present study presents an overview of the main features of the seismic ground shaking during the Amatrice earthquake. We analyze the ground motion characteristics of the main shock in terms of peak ground acceleration (PGA), peak ground velocity (PGV) and spectral accelerations (SA, 5 per cent of critical damping). In order to understand the characteristics of the ground motions induced by Amatrice earthquake, we also study the source-related effects relative to the fault rupture directivity.</em>

scholarly journals Probabilistic Forecasting of Hydraulic Fracturing-Induced Seismicity Using an Injection-Rate Driven ETAS Model

2021 ◽  
Author(s):  
Simone Mancini ◽  
Maximilian Jonas Werner ◽  
Margarita Segou ◽  
Brian Baptie
Keyword(s):  
Hydraulic Fracturing ◽  
Shale Gas ◽  
Induced Seismicity ◽  
Risk Mitigation ◽  
Injection Rate ◽  
Aftershock Sequence ◽  
Probabilistic Forecasting ◽  
Etas Model ◽  
Epidemic Type Aftershock Sequence ◽  
Out Of Sample

Abstract The development of robust forecasts of human-induced seismicity is highly desirable to mitigate the effects of disturbing or damaging earthquakes. We assess the performance of a well-established statistical model, the epidemic-type aftershock sequence (ETAS) model, with a catalog of ∼93,000 microearthquakes observed at the Preston New Road (PNR, United Kingdom) unconventional shale gas site during, and after hydraulic fracturing of the PNR-1z and PNR-2 wells. Because ETAS was developed for slower loading rate tectonic seismicity, to account for seismicity caused by pressurized fluid, we also generate three modified ETAS with background rates proportional to injection rates. We find that (1) the standard ETAS captures low seismicity between and after injections but is outperformed by the modified model during high-seismicity periods, and (2) the injection-rate driven ETAS substantially improves when the forecast is calibrated on sleeve-specific pumping data. We finally forecast out-of-sample the PNR-2 seismicity using the average response to injection observed at PNR-1z, achieving better predictive skills than the in-sample standard ETAS. The insights from this study contribute toward producing informative seismicity forecasts for real-time decision making and risk mitigation techniques during unconventional shale gas development.

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