1 / 23

Site Categories and Amplification Factors

Site Categories and Amplification Factors. Context. Conventional PSHA (Cornell, 1968):. Attenuation Relationship Derived from PDF f(IM|m,r,…) Described by: - median - standard deviation. Attenuation Relations. Factors affecting attenuation of S a :. Tectonic regime m, r

hedy
Download Presentation

Site Categories and Amplification Factors

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Site Categories and Amplification Factors 2002 PEER Annual Meeting

  2. Context Conventional PSHA (Cornell, 1968): Attenuation Relationship Derived from PDF f(IM|m,r,…) Described by: - median - standard deviation 2002 PEER Annual Meeting

  3. Attenuation Relations Factors affecting attenuation of Sa: • Tectonic regime • m, r • Focal mechanism • Site condition - Broad site categories 2002 PEER Annual Meeting

  4. Amplification Factors • Used to adjust moments of attenuation relation • Reference site approach • e.g.: Idriss, 1990; Borcherdt and Glassmoyer, 1994; Borcherdt, 2002 • Azimuth and distance corrections • Derived error term 2002 PEER Annual Meeting

  5. Amplification Factors • Non-reference site approach • Amplification taken as residual from attenuation relation • e.g.: Sokolov, SCEC, this study • Azimuth corrections, event terms • Direct error terms 2002 PEER Annual Meeting

  6. Classification Schemes • Surface geology 2002 PEER Annual Meeting

  7. Classification Schemes • NEHRP/VS-30 Reference: Martin (1994) 2002 PEER Annual Meeting

  8. Classification Schemes • Geotechnical data Reference: Rodriguez- Marek et al. (2001) 2002 PEER Annual Meeting

  9. This Study • Large strong motion database • Leverage new geologic data sources • CDMG mapping • Borehole and geophysical data (e.g., ROSRINE) • Reference motions from Abrahamson and Silva (1997) rock attenuation • Directivity correction • Event term correction 2002 PEER Annual Meeting

  10. Data Resources • Strong motion data • PEER data set (1032 recordings from 51 eqks), up to 1999 Duzce, Turkey event • Site classifications • Surface geology • 460 age only • 240 age + depositional environment • 168 age + material texture • NEHRP, 185 sites • Geotechnical data, 183 sites 2002 PEER Annual Meeting

  11. Interpretation of Results Data Regression • Evidence of nonlinearity • Hypothesis testing • b-value departs from zero by more than its estimation error • Distinction between categories • F-test Holocene (all) 2002 PEER Annual Meeting

  12. Holocene Pleistocene 2002 PEER Annual Meeting

  13. Discussion of Results • Effect of period • Distinct categories for each scheme • Comparison to previous studies • Inter-category error • Measure of relative effectiveness of classification schemes 2002 PEER Annual Meeting

  14. Effect of Period Holocene Age-only 2002 PEER Annual Meeting

  15. Surface Geology Holocene lacustrine/marine Quaternary alluvium Age + Depositional Environment Mesozoic + Igneous Tertiary 2002 PEER Annual Meeting

  16. Surface Geology Age + Material Texture Holocene Coarse Holocene Fine 2002 PEER Annual Meeting

  17. NEHRP B C D 2002 PEER Annual Meeting

  18. Geotechnical Data C B D E 2002 PEER Annual Meeting

  19. Comparison C D 2002 PEER Annual Meeting

  20. Comparison 2002 PEER Annual Meeting

  21. Inter-Category Error Terms • Individual residual • Category residual • Scheme residual • Inter-category error 2002 PEER Annual Meeting

  22. Results: “Soil” Categories 2002 PEER Annual Meeting

  23. Final Remarks • Desired features of classification schemes: • Minimize dispersion (detailed geology) • Categories have distinct amplification levels (NEHRP) • Amplification factors smaller than design standards • Further improvements require consideration of basin geometry 2002 PEER Annual Meeting

More Related