1. Full-3D Tomography of Crustal Structure in Central California
1En-Jui Lee, 1Thomas H. Jordan, 2Po Chen, 1Philip J. Maechling, 3Pierre Boué, 4Marine Denolle, 3Gregory C. Beroza, 1William K. Eymold
1 Southern California Earthquake Center, University of Southern California
2Department of Geology and Geophysics, University of Wyoming
3 Department of Geophysics, Stanford University
4 Scripps Institute of Oceanography, University California San Diego

2. Central California New Melones Dam High seismic risk
Diablo canyon power plant
Dam safety (Sierra Navada)
New Melones Dam

3. The initial model NC : Xu et al.’s (2013) NC model
3 full-3D tomography (F3DT) iterations
SC : Lee et al.’s (2014)
26 F3DT iterations
CVM-S4.26
Background: Lin et al.’s (2010) state-wide model
NC model
CVM-S4.26

4. Waveform Data Ambient-noise Green’s functions (ANGFs)
Improve data coverage
Source and receiver locations are known
Different frequencies have sensitivity for different depths
Ma et al., (2008), BSSA

5. ANGFs waveform examples
From a station at Parkfield to other stations
Bandpass 0.11~0.18 Hz
Bandpass 0.03~0.10 Hz
Cross the
Great Valley
Ambient noise Green’s function data from Dr. Beroza’s group

6. ANGF Dataset 5th iteration 200 stations
ANGFs among various instruments
Broadband stations
Short-period stations
Very good data coverage for our study area

7. Waveform Processing CWT Separate seismic phases Find wave- form pairs
Freq. dependent measure-ments TW
ICWT
Lee & Chen, (2013), GJI

8. Measurements More than 12,000 windows
More than 59,000 frequency dependent measurement

9. Results
Sum of RWM reduces about 28.5%

10. Results
Variance of dtg reduces about 56%

11. 5th iteration model Heal the velocity artifacts in the initial model
Increase the velocity gradient across SAF
Enhance basin structures
Great Valley
Cuyama Basin

12. ANGF Waveform examples
Initial waveforms
Updated waveforms
Black: data
Red: synthetic
Initial waveforms
Updated waveforms

13. Southern Great Valley Similar basin structures Shallow Deep Harvard’s
basin model
Deep

14. Future work Merge Harvard’s basin model for near surface velocity
Earthquake source inversion based on updated velocity model
Including earthquake waveforms for more iteration
Physics-Based Seismic Hazard Model for Central California

15. Earthquake Source Inversion
More accuracy velocity model  Earthquake source inversions & seismic hazard analysis

16. Summary Use of ANGF data to improve data coverage
Heal the velocity artifacts in the initial model
Reveal basin & fault structures
Improve waveform fittings
Future Work
Earthquake source inversion
Physics-Based Seismic Hazard Model