Next-Level ShakeZoning for Earthquake Hazard Definition in the Intermountain West John N. Louie, with Will Savran, Brady Flinchum, Gabriel Plank, Will Savran, Brady Flinchum, Gabriel Plank, Graham Kent, Kenneth D. Smith Nevada Seismological Laboratory Satish K. Pullammanappallil, Aasha Pancha Optim Seismic Data Solutions Werner K. Hellmer Clark County Dept. of Development Services J. Louie, CTBTO S&T, 8 June 2011

Seismic-Hazard Mapping in Nevada  Goal is to predict earthquake shaking For hazard mapping, planning For hazard mapping, planning Building-code development and enforcement Building-code development and enforcement Provide time histories of shaking to designers Provide time histories of shaking to designers Shaking characteristics of Nevada geology affect NTS data sets and arrays Shaking characteristics of Nevada geology affect NTS data sets and arrays  USGS ShakeMap Based on statistical averages; sparse data Based on statistical averages; sparse data Most data came from California, Japan, Taiwan– Geology not similar to Nevada Most data came from California, Japan, Taiwan– Geology not similar to Nevada J. Louie, CTBTO S&T, 8 June 2011

New, Dense Data Sets Enable “Next-Level ShakeZoning”  Next-Level ShakeZoning for Nevada and Intermountain Western US Based on: Wave Physics Based on: Wave Physics Geological & Geotechnical data Geological & Geotechnical data Parcel Map unsurpassed in detailParcel Map unsurpassed in detail Validating against Nevada earthquake records Validating against Nevada earthquake records Complete gridding software and data sets available from crack.seismo.unr.edu/ma Complete gridding software and data sets available from crack.seismo.unr.edu/ma J. Louie, CTBTO S&T, 8 June 2011

Clark County & Henderson Parcel Map 10,721 Measurements Parcel Class for IBC J. Louie, CTBTO S&T, 8 June 2011

Build Parcel Map into ShakeZoning Does it Make a Difference? ShakeZoning Geotech Vs30 Map Warmer colors: lower Vs30 (meter) Parcel Map on top of IBC default Vs30 J. Louie, CTBTO S&T, 8 June 2011

Adding Fault and Basin Geology Black Hills Fault in Google Earth with USGS Qfaults trace USGS Basin Map J. Louie, CTBTO S&T, 8 June 2011

Adding Physics  Black Hills M6.5 event Short trace but 4-m scarps noted Short trace but 4-m scarps noted  LLNL’s E3D (Larsen) and WPP (Petersson) viscoelastic F-D solutions 0.5-Hz frequency 0.5-Hz frequency 0.20-km grid spacing 0.20-km grid spacing A few hours on our small cluster A few hours on our small cluster  Mode conversion, rupture directivity, reverberation, trapping within and tunneling between basins J. Louie, CTBTO S&T, 8 June 2011

Black Hills M6.5 Scenario Results  Max Peak Ground Velocity (PGV) >140 cm/sec  PGV over 60 cm/sec (yellow) bleeds into Las Vegas basin from an adjacent basin  Large event for a short fault Unlikely, but add to hazard probabilistically Unlikely, but add to hazard probabilistically J. Louie, CTBTO S&T, 8 June 2011

Surprising Effect of Parcel Map Over IBC Defaults 1-D Amplification Used in IBC, ShakeMap 3-D Amplification from ShakeZoning

J. Louie, CTBTO S&T, 8 June 2011 ShakeMap versus ShakeZoning Yellow is 60 cm/sec on both Yellow is 60 cm/sec on both Geotech estimated from topography Geotech estimated from topography ShakeZoning shows trapping in basins ShakeZoning shows trapping in basins Hazard map is difficult to predict Hazard map is difficult to predict

Wells, NV M6.0 2/21/2008  NW-steep-dip fault from initial Dreger CMT  Eastward rupture directivity  Many basins channel shaking J. Louie, CTBTO S&T, 8 June 2011

Wells, NV M6.0 2/21/2008  PGV map  Eastward rupture directivity  Many basins channel shaking

With Many Scenarios, Define Probabilistic Hazard J. Louie, EGGE 3/25/2011  Japan and New Zealand Lesson: Don’t Ignore Worst Case! dePolo, 2008, NBMG Map 167

Parcel Mapping Surface-Wave Arrays Every One Hand-Modeled J. Louie, CTBTO S&T, 8 June 2011

Blind Tests of Parcel Map  Different: Equipment Field crew Dispersion interpreter Vs(z) modeler  Match to Map Values: 6 of 93 blind tests >10% off 13.55% max diff. 0.26% bias of average 4.92% RMS difference J. Louie, CTBTO S&T, 8 June 2011

Frenchman Mountain Fault M6.7 Scenario Possible Scarp in Neighborhood Event Inside the LVV Basin J. Louie, CTBTO S&T, 8 June 2011

2-Segment Frenchman Mtn. Fault M6.7

Effect of Parcel Map Over IBC Defaults J. Louie, CTBTO S&T, 8 June 2011

With Many Scenarios, Define Probabilistic Hazard  Recurrence Intervals: Black Hills- 15 ka Black Hills- 15 ka Frenchman Mtn.- 45 ka Frenchman Mtn.- 45 ka  e.g., PGV at UNLV: ~20 cm/s from BHF ~20 cm/s from BHF ~15 cm/s from FMF ~15 cm/s from FMF  Combine rates per annum: >15 cm/s at p.a. >15 cm/s at p.a. >20 cm/s at p.a. >20 cm/s at p.a. J. Louie, CTBTO S&T, 8 June 2011