An Evaluation of the Applicability of Current Ground-Motion Models to the South and Central American Subduction Zones

Abstract

The applicability of existing ground-motion prediction equations (GMPEs) for subduction-zone earthquakes is an important issue to address in the assessment of the seismic hazard affecting the Peru-Chile and Central American regions. Few predictive equations exist that are derived from local data, and these do not generally meet the quality criteria required for use in modern seismic hazard analyses. This paper investigates the applicability of a set of global and regional subduction ground-motion models to the Peru-Chile and Central American subduction zones, distinguishing between interface and intraslab events, in light of recently compiled ground-motion data from these regions. Strong-motion recordings and associated metadata compiled by Arango, Strasser, Bommer, Boroschek, et al. (2011) and Arango, Strasser, Bommer, Hernandez, et al. (2011) have been used to assess the performance of the candidate equations following the maximum-likelihood approach of Scherbaum et al. (2004) and its extension to normalized intraevent and interevent residual distributions developed by Stafford et al. (2008). The results of this study are discussed in terms of the transportability of GMPEs for subduction-zone environments from one region to another, with a view to providing guidance for developing groundmotion logic trees for seismic hazard analysis in these regions.

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

“…The general practice in many PSHA studies requires the extrapolation of GMPEs outside of their magnitude and distance ranges as few predictive models can satisfy all the magnitude and distance constraints imposed by each specific project. This fact is the major motivation behind the above decision and it is also implemented by other studies (e.g., Arango et al, 2012;Delavaud, Cotton, et al, 2012). Figure 8 shows the testing results of candidate GMPEs for a spectral period band ranging from T 0:0 s (PGA) to T 2:0 s. We used eight discrete period values (i.e., T 0:0, 0.1, 0.2, 0.5, 0.75, 1.0, 1.5, and 2.0 s) within this period band in order to fully understand the performance of each candidate model under the assembled ground-motion database.…”

Selection of Ground Motion Prediction Equations for the Global Earthquake Model

“…American data (Arango et al, 2012). The AEA12 model, while tested relatively sparsely, has generally performed well in the tests.…”

Challenges of Building Logic Trees for Probabilistic Seismic Hazard Analysis

“…In the PSHA conducted for the U.S. Department of Energy Hanford site in the 1990s, the Crouse (1991) and Youngs et al (1997) equations were both included in the GMC logic tree, together with two Japanese equations for PGA from subduction earthquakes that were used to scale average spectral shapes from the other two models. More recently, in the BC Hydro SSHAC Level 3 PSHA, for which several GMPEs were available for predicting spectral accelerations due to subduction earthquakes (e.g., Arango et al 2012), it would have been possible to construct a logic tree from published GMPEs without neglecting epistemic uncertainty. However, the GMC technical integrator (TI) team in the BC Hydro project concluded from their evaluation that none of these models was suitable because none were up-to-date, and proceeded to compile a global database of recordings from subduction earthquakes to derive a new GMPE.…”