1. Charles R. Real and Anthony F. Shakal California Geological Survey Turkey Flat, USA Site Effects Test Area: Blind Test of Predicted Ground Response of a Shallow Stiff-Soil Site to the September 28, 2004 M6.0 Parkfield Earthquake

2. Need to Validate Ground Motion Prediction Models Theory Data Observation Supposition Hypothesis Measurement Toward Knowledge Experimentation Model Validation Specific Case

3. Background 1985 IASPEI/IAEE Resolution to: –Promote establishment of test sites around world to validate methods of predicting effects of surface geology on seismic motion –Form Joint Working Group to provide guidance for establishing test sites 1986 CGS/CSMIP established test site at Turkey Flat near Parkfield, CA

4. Blind Test Approach Conduct high quality field and laboratory tests to characterize the geotechnical properties of the site Collect high-quality measurements of ground response in sediment basin and bordering rock Distribute only rock records and request predictions at basin recording sites Release observed basin recordings of and compare with predictions

5. Turkey Flat Site Effects Test Area

6. Experiment Timeline ActivityWhen 1. Geotechnical site characterization1986 2. Accelerograph Installation1987 3. Weak-motion data collection1988-89 4. Weak-motion prediction test1990 5. Strong-motion data collection? 6. Strong-motion prediction test?

7. Field Tests

8. Lab Tests

9. Seismic Reflection & Refraction Surveys

10. Turkey Flat Site Effects Test Area R1, D1 V1, D2, D3 V2 R2 B B A A C C Next slide shows profiles

11. Geologic Structure

12. Experiment Timeline ActivityWhen 1. Geotechnical site characterization1986 2. Accelerograph Installation1987 3. Weak-motion data collection1988-89 4. Weak-motion prediction test1990 5. Strong-motion data collection? 6. Strong-motion prediction test? Accelerographs Installed Weak-motion Data Collection

13. Weak Motion Test Country/ParticipantsStandardPreferred Canada (1) 1 1 China (2) 2 Czechoslovakia (2) 2 France(4) 3 1 Germany (1) 1 Italy (3) 1 1 Japan (13) 7 2 Mexico (1) 1 New Zealand (1) 1 USA (13) 6 1 Totals 41 6

14. New Experiment Timeline ActivityWhen 1. Geotechnical site characterization1986 2. Accelerograph Installation1987 3. Weak-motion data collection1988-89 4. Weak-motion prediction test1990 5. M6.0 Parkfield Earthquake9/28/2004 6. Strong-motion prediction test2005

15. Required Strong-Motion Predictions Fourier Amplitude Spectral Ratios: –1) X i /R1 given R1 (where X i means D1, D2, D3, V1,V2, R2) –2) V1/D3, D2/D3 given D3 D3 D2 D1 R1 V1 V2 R2 Two-step process: R1 predictions (4 months) Then: D3 predictions (3 months)

16. Required Strong-Motion Predictions Acceleration Time Histories: –(1) V1, D2, D3 given R1 –(2) V1, D2 given D3 D3 D2 D1 R1 V1 V2 R2

17. Required Strong-Motion Predictions Psuedovelocity Response Spectra (5% damped) & peak values displ, vel, accel: –1) X i given R1 (where X i means D1, D2, D3, V1,V2, R2) –2) V1, D2 given D3 D3 D2 D1 R1 V1 V2 R2

18. Terms/Conditions Predictions are voluntary and at own expense Required predictions must be complete as requested, and carried out using a preferred geotechnical model developed from data provided All predictions must include estimates of uncertainty Individuals/groups shall remain anonymous when evaluating/comparing prediction results

19. Optional Predictions (encouraged) Full required set as described, but using the standard geotechnical model Time histories for V2, R2 given R1 for preferred geotechnical model Time histories for V2, R2 given R1 for standard geotechnical model Compute vertical components for all predictions

20. SM Prediction Timeline Announcement of test12/2004 Given-R1 predictions due9/2005 Given-D3 prediction begins 10/2005 Given-D3 predictions due11/2005 Workshop Spring 2006

21. Workshop Timeline WorkshopWhen 1. Vancouver, B.C.1987 2. Tokyo, Japan1992 3. San Francisco, CASpring 2006

22. Turkey Flat Working Group Stay Tuned…….. www.quake.ca.gov/Parkfield_2004