Özkan Kale

A New Procedure for Selecting and Ranking Ground-Motion Prediction Equations (GMPEs): The Euclidean Distance-Based Ranking (EDR) Method

Abstract We introduce a procedure for selecting and ranking of ground‐motion prediction equations (GMPEs) that can be useful for regional or site‐specific probabilistic seismic hazard assessment (PSHA). The methodology is called Euclidean distance‐based ranking (EDR) as it modifies the Euclidean distance ( DE ) concept for ranking of GMPEs under a given set of observed data. DE is similar to the residual analysis concept; its modified form, as discussed in this paper, can efficiently serve for ranking the candidate GMPEs. The proposed procedure separately considers ground‐motion uncertainty (i.e., aleatory variability addressed by the standard deviation) and the bias between the observed data and median estimations of candidate GMPEs (i.e., model bias). Indices computed from the consideration of aleatory variability and model bias or their combination can rank GMPEs to design GMPE logic trees that can serve for site‐specific or regional PSHA studies. We discussed these features through a case study and ranked a suite of GMPEs under a specific ground‐motion database. The case study indicated that separate consideration of ground‐motion uncertainty (aleatory variability) and model bias or their combination can change the ranking of GMPEs, which also showed that the ground‐motion models having simpler functional forms generally rank at the top of the list. We believe that the proposed method can be a useful tool to improve the decision‐making process while identifying the most proper GMPEs according to the specific objectives of PSHA. Online Material: MATLAB script and sample input file for EDR index calculation.

A Model for Vertical-to-Horizontal Response Spectral Ratios for Europe and the Middle East

In the framework of probabilistic seismic hazard analysis, the preferred approach for obtaining the response spectrum of the vertical component of motion is to scale the horizontal spectrum by vertical-to-horizontal (V/H) spectral ratios. In order to apply these ratios to scenario or conditional mean spectra, the V/H ratios need to be defined as a function of variables such as magnitude, distance, and site classification. A new model for the prediction of V/H ratios for peak ground acceleration and spectral accelerations from 0.02 to 3.0 s is developed from the database of strong-motion accelerograms from Europe and the Middle East. A simple functional form, expres- sing the V/H ratios as a function of magnitude, style of faulting, distance, and site class, is found to be appropriate, and the associated aleatory variability is found to be at least as low as that obtained in other studies using more complex models. The predicted ratios from the new European model are found to be in broad agreement with recent models derived from predominantly western North America data.

The 2014 seismic hazard model of the Middle East: overview and results

The Earthquake Model of Middle East (EMME) Project aimed to develop regional scale seismic hazard and risk models uniformly throughout a region extending from the Eastern Mediterranean in the west to the Himalayas in the east and from the Gulf of Oman in the south to the Greater Caucasus in the North; a region which has been continuously devastated by large earthquakes throughout the history. The 2014 Seismic Hazard Model of Middle East (EMME-SHM14) was developed with the contribution of several institutions from ten countries. The present paper summarizes the efforts towards building a homogeneous seismic hazard model of the region and highlights some of the main results of this model. An important aim of the project was to transparently communicate the data and methods used and to obtain reproducible results. By doing so, the use of the model and results will be accessible by a wide community, further support the mitigation of seismic risks in the region and facilitate future improvements to the seismic hazard model. To this end all data, results and methods used are made available through the web-portal of the European Facilities for Earthquake Hazard and Risk (www.efehr.org).

Evolution of seismic hazard maps in Turkey

A review on the historical evolution of seismic hazard maps in Turkey is followed by summarizing the important aspects of the updated national probabilistic seismic hazard maps. Comparisons with the predecessor probabilistic seismic hazard maps as well as the implications on the national design codes conclude the paper.

Uncertainty in Nonlinear SDoF Response Due to Long-Period Noise of Accelerograms

The behavior of nonlinear oscillator deformations due to the long-period noise in strong ground motions is investigated. Inelastic spectral and residual displacements (SDIE and SDR, respectively) are selected to represent the nonlinear deformations of single-degree-of-freedom (SDoF) systems. Within this context, the interaction between these deformation demand parameters and high-pass filtering that is used for removing the long-period noise is examined. Analyses indicate that the high-pass filter values can influence the reliability of SDIE and SDR depending on the recording quality, level of inelasticity and magnitude variations. Usable spectral period ranges are proposed for SDIE through probabilistic methodologies where the adverse effects of high-pass filtering are minimal.

Erratum to: A model for predicting vertical component peak ground acceleration (PGA), peak ground velocity (PGV) and 5% damped pseudospectral acceleration (PSA) for Europe and the Middle East

In this study, we present a ground-motion model for the vertical component of peak ground acceleration, peak ground velocity, and 5% damped pseudo acceleration response spectra at periods ranging from 0.01 to 4 s. The vertical model is based on the ground-motion models previously developed for the horizontal component and vertical-to-horizontal ratio of ground motion by Akkar et al. (Bull Earthq Eng 12:359–387, 2014a; 517–547, 2014b) rather than on an independent regression analysis of strong-motion data available for Europe and the Middle East. The proposed ground-motion model includes formulations for the median values as well as for the aleatory within-event, between-event, and total standard deviation values of the vertical ground motion. We validate the proposed model by comparing it against the strong-motion database of Europe and the Middle East. Our vertical ground-motion model is applicable for moment magnitudes ranging from 4.0 to 8.0, for source-to-site distances ranging from 0 to 200 km, average shear-velocity down to 30 m (Vs30) values ranging from 150 to 1200 m/s and for reverse, normal and strike-slip styles of faulting as is the case for the underlying horizontal component and vertical-to-horizontal ratio ground-motion models of Akkar et al. (2014a, b). Within the scope of this study, a method to develop a vertical spectrum that is fully consistent with the corresponding horizontal uniform hazard spectrum is also proposed.

Developments in Ground Motion Predictive Models and Accelerometric Data Archiving in the Broader European Region

This paper summarizes the evolution of major strong-motion databases and ground-motion prediction equations (GMPEs) for shallow active crustal regions (SACRs) in Europe and surrounding regions. It concludes with some case studies to show the sensitivity of hazard results at different seismicity levels and exceedance rates for local (developed from country-specific databases) and global (based on databases of multiple countries) GMPEs of the same region. The case studies are enriched by considering other global GMPEs of SACRs that are recently developed in the USA. The hazard estimates computed from local and global GMPEs from the broader Europe as well as those obtained from global GMPEs developed in the US differ. These differences are generally significant and their variation depends on the annual exceedance rate and seismicity. Current efforts to improve the accelerometric data archives in the broader Europe as well as more refined GMPEs that will be developed from these databases would help the researchers to understand the above mentioned differences in seismic hazard.