1. Preliminary PEER-NGA Ground Motion Model Brian Chiou and Robert Youngs PEER-NGA Workshop 7 December 3, 2004

2. Data Selection Excluded Gorda plate earthquakes – oceanic crust Excluded subduction zone earthquakes Excluded records in basements Excluded records in large structures Included dam abutment records

3. Modeling Concepts Source scaling –Magnitude –Aspect Ratio –Depth (focal depth) –Style of faulting Distance scaling –Closest distance –Effect of Q for large distances –Hanging Wall (to be examined)

4. Modeling Concepts (cont’d) Site Effects –Function of V S30 (will examine effect of using categories) –Nonlinear site amplification (using empirical data guided by modeling results) –Depth to V S ~ 1 and/or 1.5 km/s

5. Model Form Reference site motion Site effects

6. Inter-Event Residuals

7. Intra-event Residuals PGA Model 1

8. Intra-event Residuals PGA Model 2

9. Intra-event Residuals SA 1 Hz Model 1

10. Intra-event Residuals SA 1 Hz Model 2

11. Model 1 (magnitude only) PGA on Rock (V S30 =600m/s)

12. Model 2 (magnitude & aspect ratio) PGA on Rock (V S30 =600m/s)

13. Model 1 (magnitude only) 1 Hz SA on Rock (V S30 =600m/s)

14. Model 2 (magnitude & aspect ratio) 1 Hz SA on Rock (V S30 =600m/s)

15. Model 1 (magnitude only) PGA on Soil (V S30 =280m/s)

16. Model 1 (magnitude only) 1Hz SA on Soil (V S30 =280m/s)