1. Simulation of Seismic-Wave Propagation Through the Lake Tahoe Basin, Calif.-Nevada: A Scenario Approach to Probabilistic Shaking Hazard Gretchen C. Schmauder 1,2, John N. Louie 1,3, Satish Pullammanappallil 2, Kyle Gray 1, Kevin McBean 1, Alexa McBean 1, & Graham M. Kent 1 1.Nevada Seismological Lab. & Dept. Geol. Sci. & Engin., Univ. of Nevada, Reno NV, USA 2.Optim SDS, 200 S. Virginia St. Suite 560, Reno, NV USA; gretchens@optimsds.com gretchens@optimsds.com 3.visiting Victoria University of Wellington to August 2014 Thanks to: J. M. Maloney (Univ. of Calif. San Diego); Edgetech; Watershed Sciences; Tahoe Regional Planning Agency; U.S. Forest Service crack.seismo.unr.edu/NSZ

2. 1) Finding Earthquake Source Faults: 2  Marine CHIRP under Lake Tahoe  Dense LiDAR under trees LV LA SF Results: Only 3 faults! (Pyramid L. has 100s) All normal, N- strike, E-dip, E-W extension M7.5 events in record

3. CHIRP images sediments to 70 m below lake bottom with 25 cm resolution 3 Edgetech acoustic Compressed High Intensity Radar Pulse (CHIRP) With Univ. of California, San Diego Slide/gravity deposits seen throughout Tahoe; dated & correlated by Shane Smith.

4. 4 Watershed Sciences airborne Light Detection and Ranging (LiDAR) imagery over 232,000 acres in the Tahoe basin

5. 5 2) Gravity and ReMi™ Assess Wave Trapping in Basins, and Geotechnical Amplification Assembled Basin Thickness Assembled Basin Thickness

6. 6 Assembled Vs30 200-m Grid Vs 200-m Grid Vs Assembled Vs30 Map Assembled Vs30 Map

7. 7 Intense 3D basin effects Intense 3D basin effects   NSZ WTDPF Rupture from South Large motions for:  Steep slopes  Small subbasins Large motions for:  Steep slopes  Small subbasins 3) Shake- Zoning Scenario Predictions Using Physics and Geology PGV Shaking Map PGV Shaking Map

8. How to explain hazard to the community? 4) Probabilistic Mapping with ShakeZoning Scenarios 8 Frankel et al. USGS Seattle Basin – Annual Probability of Exceedance λ:  Sum up a limited number of scenarios: faults; rupture directivities.  Examine Annual Rate of Exceedance (A.R.E.) of μ 0 =30 cm/s.  Conflate PGV > 30 cm/s with higher A.R.E.; <30 cm/s, lower A.R.E.

9. Shaking Map to Hazard Map 9 PGV Shaking Map PGV Shaking Map  7x10 -5 /year PGV  rate  PGV  rate  A.R.E. Map A.R.E. Map WTDPF So. Rupture, One Scenario

10. Now add up the A.R.E.s for the 6 fault scenarios: Result: a simple tool promoting resilience 10