2,001 research outputs found
A novel approach to assessing nuisance risk from seismicity induced by UK shale gas development, with implications for future policy design
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 GutenbergâRichter distribution for tectonic events. Finally, we discuss how the framework can be used to inform relevant policy
Retrospective Evaluation of the Five-Year and Ten-Year CSEP-Italy Earthquake Forecasts
On 1 August 2009, the global Collaboratory for the Study of Earthquake
Predictability (CSEP) launched a prospective and comparative earthquake
predictability experiment in Italy. The goal of the CSEP-Italy experiment is to
test earthquake occurrence hypotheses that have been formalized as
probabilistic earthquake forecasts over temporal scales that range from days to
years. In the first round of forecast submissions, members of the CSEP-Italy
Working Group presented eighteen five-year and ten-year earthquake forecasts to
the European CSEP Testing Center at ETH Zurich. We considered the twelve
time-independent earthquake forecasts among this set and evaluated them with
respect to past seismicity data from two Italian earthquake catalogs. In this
article, we present the results of tests that measure the consistency of the
forecasts with the past observations. Besides being an evaluation of the
submitted time-independent forecasts, this exercise provided insight into a
number of important issues in predictability experiments with regard to the
specification of the forecasts, the performance of the tests, and the trade-off
between the robustness of results and experiment duration. We conclude with
suggestions for the future design of earthquake predictability experiments.Comment: 43 pages, 8 figures, 4 table
Simulation of seismic events induced by CO2 injection at In Salah, Algeria
Date of Acceptance: 18/06/2015 Acknowledgments The authors would like to thank the operators of the In Salah JV and JIP, BP, Statoil and Sonatrach, for providing the data shown in this paper, and for giving permission to publish. Midland Valley Exploration are thanked for the use of their Move software for geomechanical restoration. JPV is a Natural Environment Research Council (NERC) Early Career Research Fellow (Grant NE/I021497/1) and ALS is funded by a NERC Partnership Research Grant (Grant NE/I010904).Peer reviewedPublisher PD
Spatiotemporal seismic hazard and risk assessment of M9.0 megathrust earthquake sequences of wood-frame houses in Victoria, British Columbia, Canada
Megathrust earthquake sequences, comprising mainshocks and triggered aftershocks along the subduction interface and in the overriding crust, can impact multiple buildings and infrastructure in a city. The time between the mainshocks and aftershocks usually is too short to retrofit the structures; therefore, moderateâsize aftershocks can cause additional damage. To have a better understanding of the impact of aftershocks on cityâwide seismic risk assessment, a new simulation framework of spatiotemporal seismic hazard and risk assessment of future M9.0 sequences in the Cascadia subduction zone is developed. The simulation framework consists of an epidemicâtype aftershock sequence (ETAS) model, groundâmotion model, and stateâdependent seismic fragility model. The spatiotemporal ETAS model is modified to characterise aftershocks of large and anisotropic M9.0 mainshock ruptures. To account for damage accumulation of woodâframe houses due to aftershocks in Victoria, British Columbia, Canada, stateâdependent fragility curves are implemented. The new simulation framework can be used for quasiârealâtime aftershock hazard and risk assessments and cityâwide postâevent risk management.For this work, K.G. received funding from the Canada Research Chair program (950-232015) and the NSERC Discovery Grant (RGPIN-2019-05898), and M.J.W. received funding from the European Union's Horizon 2020 research and innovation program (No 821115, RISE: Real-Time Earthquake Risk Reduction for a Resilient Europe). L.Z. and M.J.W. appreciate the support from the London Mathematical Laboratory (http://lml.org.uk/). M.J.W. was also supported by the Southern California Earthquake Center (No. 10013); SCEC is funded by NSF Cooperative Agreement EAR-1600087 & USGS Cooperative Agreement G17AC00047
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