The ranges of uncertainty among the use of NGA-west1 and NGA-west 2 ground motion prediction equations

Abstract

In this study, a comparison of the use of NGA-West1 and NGA-West2 ground motion prediction equations (GMPEs) to estimate peak ground acceleration (PGA) and spectral acceleration (SA) at 1.0 s for moderate to high seismic hazard area have been presented. This paper focuses on updated estimated ground motion due to the use of NGA-West2, and their impact on the hazard map related to those estimated by NGA-West1 for two cities in South East Asia with different level of seismic hazard. In addition, comparison of the range of epistemic uncertainty between NGA-West1 and NGA-West2 have also been determined. In general, the combined effects of lower medians and increased standard deviations in the new GMPEs have caused only small changes, within 5–20%, in the probabilistic ground motions for considered sites compared to the previous results. In addition, the results illustrate that the variation in seismic hazard due to GMPEs seems to be lower for NGA-West2 comparing to NGA-West1 for area with controlling earthquake magnitude of 6.0–6.5. However, for area with controlling earthquakes of small magnitudes in the range 5.5–6.0 or very strong earthquakes (M > 7.5), the variations in seismic hazard seems to be similar for both NGA-West1 and NGA-West2.