...Keith Porter, M.EERI; Kevin Milner; Edward Field, M.EERI The Uniform California Earthquake Rupture Forecast version 3-Time Dependent depicts California’s seismic faults and their activity. Its logic tree has 5760 leaves. Considering 30 more model combinations related to ground motion produces...

... modifications to the Bea22 procedures for the host‐to‐target adjustments, one for the source and one for the anelastic attenuation function. The first modification is to compute logic‐tree branches for the source adjustment variable Δ c M given in Bea22 assuming that the host‐ and target‐region stress...

...David M. Boore; Robert R. Youngs; Albert R. Kottke; Julian J. Bommer; Robert Darragh; Walter J. Silva; Peter J. Stafford; Linda Al Atik; Adrian Rodriguez‐Marek; James Kaklamanos ABSTRACT The purpose of a median ground‐motion logic tree is to capture the center, body, and range of possible ground...

...Keith Porter, M. EERI; Edward Field, M. EERI; Kevin Milner The size of the logic tree within the Uniform California Earthquake Rupture Forecast Version 3, Time-Dependent (UCERF3-TD) model can challenge risk analyses of large portfolios. An insurer or catastrophe risk modeler concerned with losses...

...Özkan Kale, M. EERI; Sinan Akkar, M. EERI We propose a methodology that can be useful to the hazard expert in building ground-motion logic trees to capture the center and range of ground-motion amplitudes. The methodology can be used to identify a logic-tree structure and weighting scheme...

... for this purpose is the logic tree. Notwithstanding its vast popularity, the logic‐tree outcomes are still interpreted in two different and irreconcilable ways. In one case, practitioners claim that the mean hazard of the logic tree is the hazard and the distribution of all outcomes does not have any probabilistic...

... of the logic trees representing the full range of uncertainty in the seismic source characterization ( SSC ) and ground‐motion characterization ( GMC ) models. A promising approach for addressing this requirement is illustrated with a practical example from a PSHA project for the Thyspunt nuclear site...

... ( Working Group on California Earthquake Probabilities [WGCEP], 2007 ; Field et al. , 2009 ). UCERF2 contains 480 logic‐tree branches reflecting choices among nine modeling uncertainties in the earthquake rate model shown in Figure  1 . For seismic hazard analysis, it is also necessary to choose a ground...

...Frank Scherbaum; Nicolas M. Kuehn Logic trees have become the most popular tool for the quantification of epistemic uncertainties in probabilistic seismic hazard assessment (PSHA). In a logic-tree framework, epistemic uncertainty is expressed in a set of branch weights, by which an expert...

... in the region. The computer program applied in the analysis, FRISK88M ( Risk Engineering, 1996 ), utilizes a logic tree approach to account for uncertainties and weights of the various input parameters, i.e. , the data set (magnitudes), regionalization model or completeness criteria, attenuation function...

...Christopher Roth, M.EERI The seismic performance of a nonstructural secondary system depends on the performance of each component of the system, and on the way in which the components are connected. The performance of each component is commonly described using fragility curves. Logic trees may...

...Roger Musson An objection sometimes made against treating the weights of logic tree branches as probabilities relates to the Kolmogorov axioms, but these are only an obstacle if one believes that logic tree branches represent a seismic source model or ground motion model as being “true.” Models...

...Julian J. Bommer, M. EERI In the current practice of probabilistic seismic hazard analysis (PSHA), logic trees are widely used to represent and capture epistemic uncertainty in each element of the models for seismic sources and ground-motion prediction. Construction of a logic tree involves...

...Julian J. Bommer, M.EERI; Frank Scherbaum, M.EERI Logic trees have become a standard feature of probabilistic seismic hazard analyses (PSHA) for determining design ground motions. A logic tree's purpose is to capture and quantify the epistemic uncertainty associated with the inputs to PSHA and thus...

...Frank Scherbaum; Julian J. Bommer; Hilmar Bungum; Fabrice Cotton; Norm A. Abrahamson Abstract Logic trees have become a popular tool in seismic hazard studies. Commonly, the models corresponding to the end branches of the complete logic tree in a probabalistic seismic hazard analysis ( psha...

...Julian J. Bommer; Frank Scherbaum; Hilmar Bungum; Fabrice Cotton; Fabio Sabetta; Norman A. Abrahamson Abstract Logic trees are widely used in probabilistic seismic hazard analysis as a tool to capture the epistemic uncertainty associated with the seismogenic sources and the ground-motion prediction...

...Nitzan Rabinowitz; David M. Steinberg; Gideon Leonard This article explains the essential duality between logic tree analysis and sensitivity analysis in probabilistic seismic hazard assessment. The results of a logic tree analysis can be used to carry out a sensitivity analysis. More important...