SCEC Award Number 14170 View PDF
Proposal Category Individual Proposal (Integration and Theory)
Proposal Title Hazus Probabilistic Loss Estimates for California: Evaluation of Losses for NGA-West 2 and Time-Dependent UCERF3 Ground Motions
Investigator(s)
Name Organization
Hope Seligson MMI Engineering
Other Participants
SCEC Priorities 6e SCEC Groups EEII, CME, GMSV
Report Due Date 03/15/2015 Date Report Submitted N/A
Project Abstract
 This research project examines the variation of annualized loss estimates predicted for California using the Federal Emergency Management Agency’s Hazus natural hazard risk assessment software and seismic hazard data developed using the enhanced Next Generation Attenuation Relationships for the Western US (NGA-West2) Ground Motion Prediction Equations (GMPEs). A total of fifteen statewide annualized loss analyses have been conducted using Hazus-MH Maintenance Release 4 to evaluate the difference in losses for UCERF3-based time independent hazard data generated using the NGA-West2 GMPEs, individually and averaged, without soil amplification, with soil amplification integrated into the GMPEs, or using either the original NERHP soil amplification factors or the recently updated factors. Results show that statewide annualized loss increases are significantly larger when soil amplification is integrated into the new GMPEs than when traditional amplification factors are used, and in comparison to earlier GMPEs. The increase in annualized building damage with soil amplification is 47% when the original NEHRP amplification factors are used with average NGA-West2 ground motions, 55% using the updated amplification factors, and 82% when amplification is computed within the GMPEs. These larger increases were unexpected, as previous studies have consistently shown at most a 50% increase in loss with soil amplification, both when integrated into GMPEs and when using amplification factors. Annualized losses computed using the individual NGA-West2 GMPEs with integrated soil data range from 63% to 96% larger than analyses conducted without soil amplification.
Intellectual Merit Establishing the capability to evaluate losses resulting from various iterations of probabilistic seismic hazard data on a consistent basis using Hazus, including multiple generations of NSHM, UCERF and NGA models and data, provides standard loss metrics (economic losses and casualties) supporting WGCEP activities, and shows the value of implementing risk analysis software to provide insights related to the enhancement of seismic hazard models over time. Demonstrating the impact of changing hazard characterization on the evolution of loss estimates also serves to highlight the importance of bridging the gap between earth science and engineering.
Broader Impacts This project evaluates the variation in annualized loss related to the selection of NGA-West2 Ground Motion Prediction Equation, and the differing treatments of soil amplification. By allowing for a direct comparison of annualized earthquake losses determined from numerous iterations of seismic hazard data, the impact of these changes can be assessed, and the level of understanding by users of both the hazard and loss information can be increased.
Exemplary Figure Figure 1: Comparison of the annualized building damage distribution estimated using the NGA-West2 GMPEs without soil amplification (pink dotted line), with soil amplification considered as part of the GMPE (thick blue dashed line) and using updated NEHRP amplification factors (thin red dashed line).