scholarly journals Core-to-Core Collaborative Research Between Earthquake Research Institute, The University of Tokyo and Disaster Prevention Research Institute, Kyoto University During FY2014 to FY2018

2020 ◽  
Vol 15 (2) ◽  
pp. 187-201
Author(s):  
Shinichi Matsushima ◽  
Keyword(s):  
Ground Motion ◽  
Seismic Risk ◽  
Collaborative Research ◽  
Risk Evaluation ◽  
Prediction Models ◽  
Epistemic Uncertainty ◽  
Disaster Prevention ◽  
Integrated Research ◽  
Earthquake Research ◽  
Research Institute

The research program titled “Earthquake and Volcano Hazards Observation and Research Program” was started in fiscal year (FY) 2014 as a new five-year project authorized and funded by the Council for Science and Technology of the Ministry of Education, Culture, Sports, Science and Technology. It included a new format of collaborative research called, “Core-to-Core Collaborative Research between Earthquake Research Institute, The University of Tokyo and Disaster Prevention Research Institute, Kyoto University.” In this format, two types of research, “Participation Type Research” and “Subject Proposal Type Research” were conducted from FY2015. A preliminary study was performed in FY2015 for “Integrated Research” of “Participation Type Research,” which developed a framework for seismic risk evaluation at prefectural offices of Osaka and Kochi for an earthquake occurring along the Nankai Trough, considering the epistemic uncertainty. The secondary study was performed from FY2016 through to FY2018, wherein the methodology for the seismic risk evaluation was improved on three aspects: i.e., revision in ground motion prediction models considering the saturation effect, revision in loss models in terms of the fatalities as well as the direct losses of buildings, and extension of target sites to the whole of Osaka and Kochi prefectures. The results suggest that the epistemic uncertainty in the ground motion prediction models is most sensitive to the overall uncertainty of seismic risk. Along with “Integrated Research,” a total of 14 “Research on Specific Topics” related to time-dependent risk analysis, economical risk evaluation, source characterization, structural damage estimation models, ground motion estimation models, soil amplification models, and disaster prevention planning considering the uncertainty of risk assessment, were studied during this period in order to improve the risk assessment studies for “Integrated Research.” With respect to “Subject Proposal Type Research,” a total of 27 individual research themes focused on research to understand hazards/risks by earthquakes and volcanic eruptions and to mitigate disasters by them.

scholarly journals Epistemic uncertainty of probabilistic building exposure compositions in scenario-based earthquake loss models

2021 ◽  
Author(s):  
Juan Camilo Gomez-Zapata ◽  
Massimiliano Pittore ◽  
Fabrice Cotton ◽  
Henning Lilienkamp ◽  
Simantini Shinde ◽  
...  
Keyword(s):  
Data Collection ◽  
Ground Motion ◽  
Seismic Risk ◽  
Epistemic Uncertainty ◽  
Fragility Functions ◽  
Aggregated Data ◽  
Basic Set ◽  
Earthquake Loss ◽  
Loss Models ◽  
The Impact

Abstract In seismic risk assessment the sources of uncertainty associated to building exposure modelling have not received as much attention as other components related to hazard and vulnerability. We are introducing that the degree of knowledge of a building portfolio can be described within a Bayesian probabilistic approach to acknowledge the epistemic uncertainty of its composition (i.e. proportions per building class). We are investigating the impact of such uncertainty on earthquake loss models through a novel approach based on an exposure-oriented logic tree arrangement and scenario-based seismic risk simulations. We have found that the building class reconnaissance either from prior assumptions by desktop studies with aggregated data (top-down approach) or from building-by-building data collection (bottom-up approach), plays a fundamental role in statistical modelling of exposure. We successively show that the selection of the basic set of building classes is a major contribution to the uncertainties in the loss estimations given their dependence on specific fragility functions. If the set of fragility functions handle multiple spectral periods, cross-correlated ground motion fields are required for the vulnerability assessment which ultimately control the variability of the losses. When the exposure composition is poorly known due to, for instance, simplifications and assumptions over aggregated data, its absolute contribution to the loss uncertainties has been found to be larger than the one imposed by the spatially distributed cross-correlated ground motion fields. This work invites to redesign desktop exposure studies, while it also highlights the importance of a standardized iterative approach to exposure data collection and modelling.

Using Large Strong Motion Datasets to Model Regional Site Response in Seismic Risk Assessment: Examples from Japan and Europe

2020 ◽  
Author(s):  
Graeme Weatherill ◽  
Fabrice Cotton ◽  
Sreeram Reddy Kotha
Keyword(s):  
Risk Analysis ◽  
Ground Motion ◽  
Seismic Risk ◽  
Site Response ◽  
Epistemic Uncertainty ◽  
Spatial Scales ◽  
Strong Motion ◽  
Site Amplification ◽  
Seismic Risk Analysis ◽  
Data Set

<p>Characterisation of seismic risk within a probabilistic framework is dependent upon well-constrained models of the seismic source, the ground motion scaling and the local site response, in addition to both their aleatory variability and epistemic uncertainty. When assessing risk as a large geographical scale such as that of a country or continent, however, complex models of site response that require detailed parameterization of the site conditions are seldom feasible to constrain. Instead, the use of simpler proxies, such as the well-known topographically inferred 30 m averaged shear-wave velocity (V<sub>S30</sub>), have become widely adopted for this purpose. In practice, the inference of V<sub>S30</sub> from topographic and/or geological proxies have substantial limitations in terms of both the geological environments for which they are appropriate and the increased uncertainty in the prediction of site response; limitations that are not always accounted for in existing seismic risk models.</p><p>The volume of data reported by both new and well-established stations is increasing at an exponential rate, with hundreds of thousands of strong motion records now available from thousands of stations. Through this enormous and ever-expanding data set it is possible to constrain thousands of station-specific amplifications and utilize this dataset to calibrate the site amplification directly upon regionally mappable parameters, which can be applied across large spatial scales needed for regional seismic risk analysis. In doing so, it is possible not only to adapt the model of site amplification to different geological environments, but also to adjust the uncertainty in the ground motion characterization to ensure that this is captured appropriately in the seismic risk analysis when using the mappable site proxies. Applications of this approach have been made for two case study regions: i) Japan, where detailed station metadata are available and the relative increase in uncertainty from using regionally-mappable parameters instead of well-constrained site properties can be constrained, and ii) Europe, where station metadata more limited but a large number of stations with repeated observations are available. The implications for the estimates of seismic losses when adopting this new approach in place of the existing methodology are illustrated using examples from the 2020 European Seismic Risk model.</p>

SEISMIC RISK ASSESSMENT AND REDUCTION IN ITALY

2019 ◽  
Vol 1 (Special Issue on First SACEE'19) ◽  
pp. 55-75
Author(s):  
Fabio Sabetta
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Safety Assessment ◽  
Public Funding ◽  
Tax Incentives ◽  
Technical Training ◽  
Disaster Prevention ◽  
Existing Buildings ◽  
Seismic Risk Assessment ◽  
Post Disaster

In this paper, the main features of the policies adopted in Italy for seismic risk reduction are discussed. Particular attention is given to the Pre-disaster prevention activities such as the implementation of the building code, the seismic risk assessment for a priority scale of intervention, tax incentives and public funding for the vulnerability reduction of the existing buildings, information to population and school education, technical training of experts. The phases of response and post-disaster activities, including emergency management, search and rescue, loss scenarios, and safety assessment of buildings, are also discussed taking example from the most recent devastating earthquakes in Italy (L.Aquila 2009, Amatrice 2016).

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.

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.

Seismic Risk Evaluation of Retrofitted Reinforced Concrete Buildings Utilizing Base Isolation and Considering Mainshock-Aftershock

2013 ◽  
Vol 671-674 ◽  
pp. 1372-1375
Author(s):  
Rui Long Han ◽  
Yue Li
Keyword(s):  
Seismic Risk ◽  
Risk Evaluation ◽  
Base Isolation ◽  
Seismic Hazards ◽  
Nonlinear Finite Element ◽  
Structural Safety ◽  
Seismic Fragility ◽  
Rc Frame ◽  
Actual Situation ◽  
Element Analysis

The insufficient consideration of seismic risk caused hidden danger for structural safety in many areas. A promising retrofit method for these structures is base isolation. In order to evaluate the effectiveness of this approach, a hypothetical RC frame based on actual situation is designed to be retrofitted using base isolation. Then, seismic fragilities for both un-retrofitted and isolated frames are analyzed, utilizing the results obtained from nonlinear finite-element analysis. The ground motion of the analysis contains 22 earthquake motions, and the results of considering mainshock-aftershock and those of considering only mainshock are compared. The study proves the well designed base isolation can reduce the seismic fragility of the RC frame effectively, and the exclusive consideration of mainshock will underestimate the seismic hazards for structures.

Evolution of the Kandilli Observatory and Earthquake Research Institute (KOERI) Seismic Network and the Data Center Facilities as a Primary Node of EIDA

2021 ◽  
Author(s):  
Musavver Didem Cambaz ◽  
Mehmet Özer ◽  
Yavuz Güneş ◽  
Tuğçe Ergün ◽  
Zafer Öğütcü ◽  
...  
Keyword(s):  
Data Center ◽  
Strong Motion ◽  
Seismic Network ◽  
Data Archive ◽  
Seismic Stations ◽  
Earthquake Research ◽  
Earthquake Research Institute ◽  
Research Facilities ◽  
Research Institute

Abstract As the earliest institute in Turkey dedicated to locating, recording, and archiving earthquakes in the region, the Kandilli Observatory and Earthquake Research Institute (KOERI) has a long history in seismic observation, which dates back to the installation of its first seismometers soon after the devastating Istanbul earthquake of 10 July 1894. For over a century, since the deployment of its first seismometer, the KOERI seismic network has grown steadily in time. In this article, we present the KOERI seismic network facilities as a data center for the seismological community, providing data and services through the European Integrated Data Archive (EIDA) and the Rapid Raw Strong-Motion (RRSM) database, both integrated in the Observatories and Research Facilities for European Seismology (ORFEUS). The objective of this article is to provide an overview of the KOERI seismic services within ORFEUS and to introduce some of the procedures that allow to check the health of the seismic network and the quality of the data recorded at KOERI seismic stations, which are shared through EIDA and RRSM.

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