Decision support system for community earthquake drills and evacuation

Decision making to mitigate the effects of natural hazards, such as earthquakes, has always been a challenging subject. This is particularly the case in periods of increased seismicity (e.g. in a foreshock or aftershock period of a major earthquake) when the population is anxious and would like advice but when the chance of potentially damaging earthquake ground motions in the coming days remains low. In this study, a decision-making method based on multiple criteria is combined with cost-benefit analyses to create a hybrid decision-making framework to help decide amongst potential loss mitigation actions. The proposed framework is demonstrated for a hypothetical case study. The results show that the proposed approach is flexible enough to adapt to new problems, end-users and stakeholders. Additionally, it is revealed that reasonable mitigation actions are viable and financially beneficial during periods of increased seismic hazard in order to reduce the potential consequences of earthquakes

Effect of epsilon-based record selection on fragility curves of typical irregular steel frames with concrete shear walls in Mashhad city

In this paper, the seismic vulnerability of Mashhad city, as the second largest city in Iran, has been investigated using analytical fragility curves. Disaggregation analysis is first performed in order to identify the target epsilon at different hazard levels. The disaggregation results revealed different epsilon values at the first mode period of two representative structures, in the case of 72-, 475-, and 2,475-year return periods. Nonlinear incremental dynamic analyses are then performed for two representative models of a typical steel frame with a concrete shear wall, using independent suites of acceleration time histories that are selected based on the target epsilons. Structural limit states are defined on each incremental dynamic analysis curve, and the corresponding damage measures are estimated. The results show that if ϵ is neglected in the considered simulations, then the predicted median structural capacities is decreased by around 10%, 15%, and 18%, respectively, for the three abovementioned hazard levels

Cost-benefit analyses to assess the potential of Operational Earthquake Forecasting prior to a mainshock in Europe

In the past couple of decades, Operational Earthquake Forecasting (OEF) has been proposed as a way of mitigating earthquake risk. In particular, it has the potential to reduce human losses (injuries and deaths) by triggering actions such as reinforcing earthquake drills and preventing access to vulnerable structures during a period of increased seismic hazard. Despite the dramatic increases in seismic hazard in the immediate period before a mainshock (of up to 1000 times has been observed), the probability of a potentially damaging earthquake occurring in the coming days or weeks remains small (generally less than 5%). Therefore, it is necessary to balance the definite cost of taking an action against the uncertain chance that it will mitigate earthquake losses. In this article, parametric cost–benefit analyses using a recent seismic hazard model for Europe and a wide range of inputs are conducted to assess when potential actions for short-term OEF are cost–beneficial prior to a severe mainshock. Ninety-six maps for various combinations of input parameters are presented. These maps show that low-cost actions (costing less than 1% of the mitigated losses) are cost–beneficial within the context of OEF for areas of moderate to high seismicity in the Mediterranean region. The actions triggered by OEF in northern areas of the continent are, however, unlikely to be cost–beneficial unless very large increases in seismicity are observed or very low-cost actions are possible

Variations in uniform hazard spectra and disaggregated scenarios during earthquake sequences

Seismic hazard varies greatly during an earthquake sequence. Understanding this variation can be useful to end-users, such as emergency managers, as it would enable them to make more informed decisions about potential risk reduction measures. This article presents examples of how two commonly-used products of probabilistic seismic hazard assess- ments: uniform hazard spectra and disaggregated earthquake scenarios, vary during two severe seismic sequences in western Greece. These calculations are made using a recent time-dependent seismic hazard model based on a Bayesian ETAS approach. The examples show that time-dependent uniform hazard spectra for short return periods (1 and 10 years) are significantly higher than standard time-independent spectra but that uniform hazard spectra for the commonly-used return periods of 475 and 2475  years are similar to those from time-independent assessments. The time-dependent spectra generally converge within a couple of days to the time-independent spectra. The examples also show that the domi- nant earthquake scenarios evidenced by the disaggregation for the time-dependent assess- ment can show significant differences from the time-independent scenarios. This is par- ticularly true when the earthquake sequence is distant from the location of interest as the aftershocks contribute greatly to the overall hazard. To show these changes more clearly this article introduces a new graphical representation of the disaggregated results: contour maps showing the magnitude or distance of the dominant earthquake scenario with axes of the structural period and response spectral acceleration

Decision support system for earthquake risk mitigation for hospitals and health facilities

Although the time of catastrophic earthquakes is not predictable, some mitigation actions can be taken to enhance preparedness against such events. Hospitals and other healthcare facilities are expected to remain operational during and after moderate to severe earthquakes. Taking mitigation measures in hospitals that are located in earthquake-prone regions is a wise decision that can lead to less damage in case of large earthquakes. Prioritizing these measures is of great importance from the economical point of view. This study employs a recent decision-making approach based on multiple criteria and cost-benefit analyses to help prioritize feasible mitigation actions for a hypothetical healthcare facility

Variations in hazard during earthquake sequences between 1995 and 2018 in western Greece as evaluated by a Bayesian ETAS model

Forecasting the spatio-temporal occurrence of events is at the core of Operational Earthquake Forecasting, which is of great interest for risk management, particularly during ongoing seismic sequences. Epidemic type aftershock sequence (ETAS) models are powerful tools to estimate the occurrence of events during earthquake sequences. In this context, a robust seismicity forecasting framework based on Bayesian-inference has been adapted to the Patras and Aegio region in western Greece (one of the most seismically active parts of Mediterranean), and an incremental adaptive algorithm is introduced to train the priors for ETAS model parameters. The seismicity forecasting is capable of accounting for uncertainty in the model parameters as well as variations in the sequence of events that may happen during the forecasting interval. Six seismic sequences between 1995 and 2018 were selected with main shock moment magnitudes Mw ≥ 6.0. The ETAS model was adapted for each seismic sequence. The number of forecasted events with Mw ≥ 4.5 and their spatial distribution was retrospectively compared with the as-recorded earthquake catalogue, confirming a good agreement between the forecasts and observations. The results show that the adapted model can be used immediately after a severe main shock to statistically predict potentially damaging earthquakes during the ongoing seismic sequence. The seismicity forecasts were translated to short-term daily exceedance rates for different thresholds of peak ground acceleration. The results reveal that the seismic hazard increased by up to 33 times in the case of the damaging 1995 Mw 6.5 earthquake in the city of Aegio. However, the results confirmed that in all six studied sequences, the increased seismic hazard decayed rapidly during the 2 d after the main shock, and remained relatively high in the following days (roughly ten times the long-term time-independent hazard)

Incorporation of Multivariate Statistical Distribution of Magnitude-Distance and Monte-Carlo Simulation in Probabilistic Seismic Hazard Analysis

The classical seismic hazard analysis is based on two independent simpli ed assumptions including the statistical distribution of mag- nitude (usually Gutenberg-Richter 1958) and the distance distribution (equal probability in each point of a given source). However, the interaction between the two distributions is rarely discussed in past researches. Therefore, a joint M-R distribution has been implemented in this paper in order to shed light into these simpli ed assumptions. The Tehran metropolis is considered as the case study since it lo- cates in a highly active seismic region. Three seismological datasets were used in this study, i.e. the observed dataset, the simulated dataset based on the Han and Choi 2008 methodology, and the simulated dataset based on the EqHaz software platform. Then, the clas- sical seismic hazard analysis results are compared with the results obtained based on the joint M-R distribution. The results show that the classical seismic hazard analysis is always conservative when compared with the results based on the simulated data

Structural global performance assessment versus individual element-oriented performance-based assessment

In this paper, three new performance indices are proposed which can be used in order to determine the global performance of a given structure. The ASCE41-13 standard and the FEMA350 guidelines are used as representatives of, respectively, an element-oriented and a system-oriented performance-based assessment algorithm. Two ten-storeyed special steel moment frames, consisting of a regular and an irregular structure, are designed and assessed using these two algorithms. The results show that the element-oriented assessment algorithm significantly underestimates the seismic demand and capacity, especially in the case of the immediate occupancy and collapse prevention limit states. This underestimation can cause a significant drop in the estimated confidence levels

A decision-making approach for operational earthquake forecasting

Decision making to mitigate the effects of natural hazards, such as earthquakes, has always been a challenging subject. This is particularly the case in periods of increased seismicity (e.g. in a foreshock or aftershock period of a major earthquake) when the population is anxious and would like advice but when the chance of potentially damaging earthquake ground motions in the coming days remains low. In this study, a decision-making method based on multiple criteria is combined with cost-benefit analyses to create a hybrid decision-making framework to help decide amongst potential loss mitigation actions (or even to take no action). The proposed framework is demonstrated for three hypothetical case studies using Patras (Greece) as an example of a high seismicity location. The results show that the proposed approach is flexible enough to adapt to new problems, end-users and stakeholders. Additionally, it is revealed that reasonable mitigation actions are viable and financially beneficial during periods of increased seismic hazard in order to reduce the potential consequences of earthquakes. Finally, the case studies show that the results can be highly sensitive to the inputs to the framework and hence it is vital to involve end users to help constrain these inputs when making such calculations

Deliverable D2.8 Revised use-cases for the FWCR Platform version 2.0 (PAR Cycle 2)

The TURNkey concept model is being developed over three cycles of participatory action research (PAR). This report describes the process and findings of the 2nd PAR cycle in the TURNkey project. In light of these findings, the report reviews the end-user use cases that were developed for TURNkey during the 1st PAR cycle (which have been reported in D2.6) and revises them in light of the discussions with end-users and TURNkey scientists, engineers and software developers that occurred during the 2nd PAR cycle. The report lays the foundation for the 3rd and final round of PAR that will be conducted for TURNkey. It will also inform TURNkey deliverable D7.7, which will provide end-users with an (exemplar) model Business Continuity and Resilience Plan (BCRP) and Disaster Management Plan (DMP) framework for integrating the TURNkey FWCR platform into their disaster management planning process. This report provides the following: Review of the key lessons from the 1st PAR Cycle Online workshops with potential end-users using a virtual demonstrator (process and findings) SWOT analysis with TURNkey scientists and engineers (process and findings) TURNkey application workshop around a hypothetical hospital scenario (process and findings) Consortium-wide reflection on findings from the 2nd PAR Cycle (process and findings) Revised end-user use cases Revised table of TURNkey features, what end-users want vs what is possible and in scope A revised version of the FWCR concept model A conclusion and next stepsThis report is intended as an internal working report for use by members of the TURNkey project in the development of the TURNkey FWCR platform. The report should be considered as a work in progress which will be amended and modified throughout the TURNkey project to reflect emerging issues identified through the 3rd PAR cycle