1. Velocity and Attenuation in the Eastern Bay Area and the Delta Donna Eberhart-Phillips UC Davis USGS Delta workshop 10 Sept 2015

2. Regional three ‐ dimensional seismic velocity model of the crust and uppermost mantle of northern California Thurber et al JGR 2009 Journal of Geophysical Research: Solid Earth Volume 114, Issue B1, B01304, 9 JAN 2009 DOI: 10.1029/2008JB005766 http://onlinelibrary.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0002 Volume 114, Issue B1, http://onlinelibrary.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0002 Used 5600 earthquakes 688 NCEDC stations Sources and stations from 13 controlled source exp Next: show some mapviews and cross-sections

3. Regional three ‐ dimensional seismic velocity model of the crust and uppermost mantle of northern California Journal of Geophysical Research: Solid Earth Volume 114, Issue B1, B01304, 9 JAN 2009 DOI: 10.1029/2008JB005766 http://onlinelibrry.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0003 Volume 114, Issue B1, http://onlinelibrry.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0003 Depth =1 km and 4 km Dashed line = topographic edge of Great Valley Franciscan, GVS

4. Regional three ‐ dimensional seismic velocity model of the crust and uppermost mantle of northern California Journal of Geophysical Research: Solid Earth Volume 114, Issue B1, B01304, 9 JAN 2009 DOI: 10.1029/2008JB005766 http://onlinelibrary.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0004 Volume 114, Issue B1, http://onlinelibrary.wiley.com/doi/10.1029/2008JB005766/full#jgrb15770-fig-0004 Depth = 8 and 14 km Dashed line = topographic edge of Great Valley GV opiolite

7. Seismic Attenuation:Qp and Qs Data t* from local earthquake spectra that give attenuation along the path Q has 1d and 3d heterogeneity Example of 1 earthquake Solution uses 959 spatially distributed earthquakes NCEDC, Mendo, SNEP (will show Delta area)

8. Results 10-km grid with linking into larger areas where little data, magenta line =low DWS Shallow: low Q in Delta and some fault zones

9. Brittle crust – low Q along fault zones with seismicity and GV margin, high Q west of CGVF and Bay block Lower crust – low Q below FZ with high cumulative displacement High Q for GV ophiolite apparent fragments in PKH –GF vicinity (Next cross-sections)

10. Vert. exag=2 PKHF uplifted fragment of ophiolite Suisun Bay may not have GVS thrust under Franciscan Basins, Franciscan, GVS, GVO

12. 3D velocity : LEQ uneven sampling and vertical smearing Surface wave have horizontal smearing and sample shallow as much or more than deep (combine) Gravity – samples whole volume including shallow, non-unique (combine) Assign shallow from stratigraphic sections (then fix shallow, free deep) The End