1. Near-field strong ground-motion data from the September 12-13, 2007 Sumatra sequence Preliminary report by Hudnut, K., C. Stephens, D. Boore, J. Galetzka, A. Acosta, J. Genrich, K. Sieh, J.-P. Avouac, T. Heaton, R. Briggs, A. Borsa and K. Stark Real-Time Monitoring & Alert Systems Scientific Requirements Workshop Leavenworth, Washington October 4, 2007

2. 2 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Acknowledgments Caltech Tectonics Observatory Jean-Philippe Avouac, Director; Kerry Sieh, Sumatra Lead Tom Heaton (K2’s), Don Helmberger, Hiroo Kanamori, Rob Clayton Jeff Genrich, John Galetzka, Rich Briggs, Aron Meltzner, Ozgun Konca, Anthony Sladen, Willy Amidon, Keith Stark (consultant) LIPI Danny Natawidjaja UCSD/SOPAC Linette Prawirodirjo, Peng Fang, Yehuda Bock U. S. Geological Survey Walter Mooney, IOTWS Lead for USGS; Bill Ellsworth - advocacy & support Ron Porcella (K2’s), Arnie Acosta, Chris Stephens, Dave Boore, Roger Borcherdt, Shane Detweiler, Woody Savage, Mehmet Celebi, Adrian Borsa

3. 3 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Sequence Overview

4. 4 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Historic rupture zones - 1797 & 1833 Outlines of rupture peripheries indicated by thin boundary lines

5. 5 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Engineering seismology PADANG - tsunami threat JAKARTA Earthquakes <600 km from Jakarta, Singapore, and Kuala Lumpur

6. 6 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Station locations SLBU PSKI

7. 7 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Pulau Sikuai - PSKI From Chris Stephens, USGS Menlo Park For the M w 8.4 at 392 km (horizontal components combined): PGA horiz. of 55.97 cm/s 2 ; ~6% g (not ‘huge’) PGV 5.9 cm/s horiz. ; -3.5 cm/s vert. For the M w 7.9 at 165 km (horizontal components combined): : PGA horiz. of 168.4 cm/s 2 ; ~17.2% g (still not ‘huge’) PGV 11.3 cm/s horiz. ; -6.8 cm/s vert. Long-Period Energy? Directivity effects?

8. 8 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Preliminary finite-fault source models Prof. Chen Ji, UCSB - M 8.4 & Yuehua Zeng, USGS - M 7.9 Thanks to Rich Briggs for the KML files!

9. 9 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 1 - M w 8.4 Velocity records for the M w 8.4 (by Dave Boore)

10. 10 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 ShakeMap Ground-Motion Prediction PGV: ~10 cm/s at Padang (computed) 6.9 cm/s (observed) Automated - based on Wald et al. (2005) and finite-fault source model by Chen Ji

11. 11 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 2 - M w 7.9 Velocity records for the M w 7.9 (by Dave Boore) note: data are un-filtered

12. 12 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI photograph Courtesy of John Galetzka; Caltech Tectonics Observatory Enclosure and solar array act as an inverted pendulum at 3-5 Hz & ~20 Hz

13. 13 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Silabu (SLBU) station photos Courtesy of John Galetzka; Caltech Tectonics Observatory Data received from JEG two days ago (10/2)  Chris Stephens set to work on it immediately  Data from M 8.4 - P-wave is missing  Data from M 7.9 - record had to be spliced  Still evaluating data - initial plots made yesterday Enganno data not yet retrieved from field. Siberut had a power malfunction and did not record data. Much closer than PSKI !

14. 14 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 SLBU Waveforms for the M w 8.4 (by Chris Stephens) note: data are un-filtered

15. 15 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 SLBU Velocity for M w 8.4 ~80 cm/sec broad pulse note: data are un-filtered

16. 16 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 SLBU Displacement for M w 8.4 note: data are un-filtered Approx. 10x larger than from GPS from Peng Fang (static) and Jeff Genrich (kinematic) - all results preliminary

17. 17 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 SLBU Spliced record for the M w 7.9 (by Chris Stephens) Three pulses of energy - Burst 1 @ 5-25 sec Burst 2 @ 35-60 sec Burst 3 @ 70-90 sec 123

18. 18 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Data processing, archiving & distribution http://www.strongmotioncenter.org/ NSMP Data Center & NCESMD partnership MUST HAVE OPEN DATA http://nsmp.wr.usgs.gov/ Take-away message: GPS and accelerometer data are complementary A robust system will likely require both for redundancy

19. Proposal - zipper array for early warning and immediate finite-fault source for San Andreas and San Jacinto fault ‘Big Ones’ IOC - 36 quadrilaterals shown @ 30 km spacing (shown) FOC - 100 quads @ 10 km spacing ($10 M init. + $3 M/yr)

20. 20 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 Backup Slides

21. 21 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 1 - M w 8.4 Waveforms for the M w 8.4 (by Chris Stephens)

22. 22 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 2 - M w 7.9 Waveforms for the M w 7.9 (by Chris Stephens)

23. 23 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 3 - M w 7.0 Waveforms for the M w 7.0 (by Chris Stephens)

24. 24 Scientific Requirements Workshop, Leavenworth, WA4 Oct 07 PSKI - Event 3 - M w 7.0 Waveforms for the M w 7.0 (by Dave Boore)