An Overview of the SIGMA Research Project: A European Approach to Seismic Hazard Analysis

1 Introduction 1.1 Overview of the project organization 1.2 Object of the document
2 General Concepts and PSHA Background 2.1 Development of a Seismotectonic Framework for PSHA 2.2 Development of Seismic Sources and Logic Trees For Source Definition 2.3 Site Specific vs. Regional Study 2.4 PSHA - A Framework for Seismic Source & Ground Motion & Site Response Characterization 2.5 Logic Tree Approach and Treatment of Uncertainties 2.5.1 Epistemic Uncertainty vs. Aleatory Variability 2.5.2 Logic Tree Methodology 2.5.3 Site Response 2.5.4 Use of Experts 2.6 Interface Issues Between Work Packages 2.7 Common Required Outputs for Seismic Hazard Results 2.7.1 Basic Definitions and Requirements 2.7.2 Common Hazard Results 2.7.3 Additional Parameters
3 Seismic source characterization3.1 Prerequisites to Develop the SSC Models 3.2 Database, Earthquake Catalogue, Magnitude Conversions, Uncertainties on Metadata 3.3 Seismic Source Models 3.3.1 Diffuse Seismicity versus Identified Seismogenic Structures 3.3.2 Seismic Source Characterization Framework 3.3.3 Area Source, Fault Sources, Gridded Seismicity 3.3.4 Lessons Learned Related to Seismic Source Models 3.4 Occurrence Processes 3.4.1 Poisson Model 3.4.2 Characteristic Model 3.4.3 Time-Dependent Seismicity Models 3.5 Maximum Magnitude and Recurrence Parameters 3.5.1 Maximum Magnitude 3.5.2 Recurrence Parameters 3.5.3 Lessons Learned 3.6 Logic-Tree Implications 3.6.1 Logic-Tree Approaches 3.6.2 Efficient Tools for the Logic-Tree Conception and Weights Assignment 3.6.3 Verification and Quality Assurance (QA)
4 Rock Motion Characterization 4.1 Empirical Models and Point Source Stochastic Models 4.1.1 Empirical Ground Motion Attenuation Models 4.1.2 Point Source Stochastic Models 4.2 Model Selection and Criteria 4.2.1 Modelling Criteria 4.2.2 Tectonic Consistency 4.2.3 Site-Conditions Consistency 4.3 Corrections or Modifications of Published Models 4.3.1 K-Vs30 (Simulation-Based) Correction 4.3.2 Data-Based Predictions for Hard Rock 4.4 Standard Deviation of Model Predictions; Truncation 4.4.1 Sigma Truncation 4.5 Approaches for the Vertical Ground Motion Component 4.6 Logic-Tree Implications 4.7 Lessons Learned from the SIGMA Project
5 Site Response Characterization 5.1 Soil Characterization 5.1.1 Determination of the profile Natural Frequency F0 5.1.2 Determination of the Shear-Wave Velocity Profile and Site Class 5.1.3 Seismic Instrumentation 5.1.4 Characterization of Nonlinear Soil Properties 5.2 Hazard Assessment at the Ground Surface 5.2.1 Direct Evaluation from Ground Motion Prediction Equations (FpG) 5.2.2 Generic Site Specific Approaches (HyG) 5.3 Completely Site Specific Approaches (HyS) 5.3.1 Linear Numerical Analyses 5.3.2 Equivalent Linear Numerical Analyses 5.3.3 Nonlinear Numerical Analyses 5.4 Treatment of Uncertainties 5.4.1 Fully Probabilistic Generic Site Approach (FpG) 5.4.2 Hybrid Site Specific Approach (HyS) 5.5 Lessons Learned from the SIGMA Project 5.6 Additional Topics in Ground Surface Hazard Assessment 5.6.1 Vertical Ground Motion 5.6.2 Maximum Ground Motion: Truncation
6 Seismic Hazard Computation 6.1 Basic Requirements 6.2 Interfaces and Boundary Conditions6.3 Software Packages 6.3.1 PSHA Software 6.3.2 Site Response Analysis Codes 6.4 Sensitivity Analysis 6.5 Hazard Disaggregation 6.6 Additional Engineering Output Parameters 6.7 Selection of Time Histories 6.7.1 Selection Based on UHS 6.7.2 Selection Based on Conditional Spectra
7 Interfaces Between Sub Projects 7.1 SSC and GMC Interfaces 7.2 GMC and SRC Interfaces 7.3 Single-Station Sigma 7.4 V/H Models for Rock and Soil
8 Probabilistic Seismic Testing and Updating of Seismic Hazard Results 8.1 PSHA Testing Using Acceleration and Macroseismic Intensity Data 8.2 Bayesian Update of PSHA
9 Summary and Way Forward
10 References
11 Annex 1: List of Committee Members 11.1 Steering Committee 11.2 Senior Hazard Analysis Review Panel - SHARP 11.3 Scientific Committee 11.4 SIGMA Work Package