1. Update on Millikan Library Research John Clinton Case Bradford V 20 May 2003 Structural Monitoring Group Meeting

2. Recent Work: Movies Hysterisis Plots Transfer Functions ModeShape Fitting

3. Movies 3 Recorded Data sets from USGS array –M3.8 April ‘98 Alhambra @ 7km –M4.8 Sept ’01 Yorba Linda @ 41km –M5.4 Feb ’03 Big Bear @ 120km Any others - M5.1Anza ‘01, M5.1Big Bear ‘01, Hector Mines ’99, local earthquakes?

4. 22 Feb 03 Big Bear M5.4 at 120km Primarily 1 st Mode resonance in both E-W and N-S directions Yorba Linda event similar – Basin waves dominate ground motion. Ref: www.ecf.caltech.edu/www.ecf.caltech.edu/~jclinton/research

5. small, local earthquake simple short period pulse as main energy input little excitation of basin waves initially 2 nd EW mode excited. After ~15s, slow emergence of 1 st mode EW resonance. 26 Apr 98 Alhambra M3.8 at 7km

6. 2 nd mode response EW 1 st mode response NS At initial S-wave pulse

7. 26 Apr 98 Alhambra M3.8 at 7km 1 st mode response EW 1 st mode response NS About 15s after initial S- wave

8. Time-Series for GSA and Millikan USGS Array (EW Channels, Displacement) No 2 nd mode on 8,9 Floors 1 st mode only appears later (long period excitation at GSA?)

9. Hysterisis Plots Attempting to recreate bi-linear stiffnesses Prof. Iwan showed last time Same method – plot relative inter-floor displacement versus force of floors above Problem: –No bilinear stiffnesses –No damping in real data, lots in forced vibrations

10. 22 Feb 03 Big Bear M5.4 at 120km EW channels note: little or no `loop’ also no change in stiffness removing part of displacement due to tilt may change shape, but will not affect damping

11. Forced Vibration EW Channels 22 Feb 03 Big Bear

12. Forced Vibration NS Channels

13. Transfer Functions Utilise new data for old method Old Method: SDOF * GSA = MIK? New Data: –USGS array for MIK –CRP for GSA

14. Yorba Linda Event MIK (9 th Floor)Roof USGS EW NS

15. Yorba Linda Event EW NS MIK (9 th Floor) length of USGS record vs full length of excitation

16. Yorba Linda Event 1 st FloorRoof EW NS 5 th Floor

17. Alhambra Event 1 st FloorRoof EW NS 5 th Floor

18. Alhambra Event – 2 nd Mode Modeling 5 th Floor 1 st Mode EW5 th Floor 2 nd Mode EW EW NS

19. Miscellaneous Notes Triggering and timing on USGS Missing Data Fixed USGS FBAs? PWP meters? ETABS model or Millikan in near future

20. Maybe some CRP noise levels if time…..