Investigators at University of Iceland Report Findings in Structural Engineering (Site Effect Estimation On Two Icelandic Strong-motion Arrays Using a Bayesian Hierarchical Model for the Spatial Distribution of Earthquake Peak Ground …)

2019 MAY 13 (NewsRx) -- By a News Reporter-Staff News Editor at Engineering Daily News -- Investigators publish new report on Engineering - Structural Engineering. According to news originating from Selfoss, Iceland, by NewsRx correspondents, research stated, “Earthquake recordings on two small-aperture (covering similar to 1.2 km(2) each) strong-motion arrays in Iceland (ICE-ARRAY I and II) exhibit considerable variations in the spatial distribution of ground-motion amplitudes. To better understand this spatial variability, we use a Bayesian Hierarchical Model (BHM) that incorporates ground motions models (GMMs) for peak ground accelerations (PGA) developed from ground motion databases recorded by the two arrays, respectively.”

Financial supporters for this research include Icelandic Centre for Research (Rannis) Grant of Excellence, University of Iceland, University of Iceland Research Fund, Marie Curie Re-integration Grant in 2006, ICEARRAY II by a Rannis Equipment Grant in 2008, Icelandic Catastrophe Insurance.

Our news journalists obtained a quote from the research from the University of Iceland, “The posterior distributions of the model parameters are then determined using Markov Chain Monte Carlo simulations in the context of Bayesian statistical methods. The BHM allows the partitioning of a GMM into event, station, and event-station terms, which in turn allows the relative contributions of source, path, and site effects to be quantified. The results indicate that site effects can dominate the spatial distribution of ground-motion parameters (e.g., PGA) observed across both ICEARRAY I and II. Although the site conditions across ICEARRAY I have been classified as uniform (i.e., ‘rock’ with a relatively flat topography), station terms contribute similar to 13% to the total variability in the amplitudes of predicted ground motions across the array. In contrast to ICEARRAY I, the variation of the geologic profiles and topography is much greater across ICEARRAY II. As a result, the inter-station variability is shown to contribute up to similar to 57% of the total variability in the amplitudes of predicted ground motions across the array, with the contributions being less constrained for ICEARRAY II than ICEARRAY I due to the relative sizes of the recorded ground motion databases. These results facilitate our understanding of the key factors that affect the variation of seismic ground motions across a relatively small area.”

According to the news editors, the research concluded: “Such a detailed microzonation is of great importance for earthquake hazard assessment on a local scale and has practical implications for engineering decision making.”

For more information on this research see: Site Effect Estimation On Two Icelandic Strong-motion Arrays Using a Bayesian Hierarchical Model for the Spatial Distribution of Earthquake Peak Ground Acceleration. Soil Dynamics and Earthquake Engineering, 2019;120():369-385. Soil Dynamics and Earthquake Engineering can be contacted at: Elsevier Sci Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, Oxon, England. (Elsevier - www.elsevier.com; Soil Dynamics and Earthquake Engineering - http://www.journals.elsevier.com/soil-dynamics-and-earthquake-engineering/)

The news correspondents report that additional information may be obtained from B. Halldorsson, University of Iceland, School of Engineering and Natural Sciences, Earthquake Engineering Research Center, Selfoss, Iceland. Additional authors for this research include S. Rahpeyma, B. Hrafnkelsson, R.A. Green and S. Jonsson.

The direct object identifier (DOI) for that additional information is: https://doi.org/10.1016/j.soildyn.2019.02.007. This DOI is a link to an online electronic document that is either free or for purchase, and can be your direct source for a journal article and its citation.

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