Next-Level ShakeZoning for Earthquake Hazard Definition in the Intermountain West John N. Louie, 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, EGGE 3/25/2011

Next-Level ShakeZoning  Goal is to predict earthquake shaking For hazard mapping, planning For hazard mapping, planning Building-code development and enforcement Building-code development and enforcement Emergency response Emergency response  USGS ShakeMap Based on statistical averages; sparse data Based on statistical averages; sparse data Most data came from California, Japan, Taiwan Most data came from California, Japan, Taiwan  Next-Level ShakeZoning for Nevada Based on: Wave Physics Based on: Wave Physics Geological & Geotechnical data from the IMW Geological & Geotechnical data from the IMW Validating against Nevada earthquake records Validating against Nevada earthquake records J. Louie, EGGE 3/25/2011

Clark County & Henderson Parcel Map 10,721 Measurements Urban Areas of County J. Louie, EGGE 3/25/2011

Clark County & Henderson Parcel Map Parcel Classification for IBC NEHRP C & D classes “C+” class for NEHRP B velocities with soft surface J. Louie, EGGE 3/25/2011

Build Parcel Map into ShakeZoning ShakeZoning Geotech Map Warmer colors: lower Vs30 (meter) Parcel Map on top of IBC default Vs30 J. Louie, EGGE 3/25/2011

Adding Fault and Basin Geology Black Hills Fault in Google Earth with USGS Qfaults trace Langenheim Basin Map J. Louie, EGGE 3/25/2011

Adding Physics  Black Hills M6.5 event Short trace but 4-m scarps noted Short trace but 4-m scarps noted  Viscoelastic finite- difference solution 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 in basins J. Louie, EGGE 3/25/2011

Black Hills M6.5 Scenario Results  Max Peak Ground Velocity (PGV) >140 cm/sec  PGV over 60 cm/sec (yellow) bleeds into LVV through Railroad Pass  Large event for a short fault Unlikely, but add to hazard probabilistically Unlikely, but add to hazard probabilistically  Need to know how unlikely J. Louie, EGGE 3/25/2011

Surprising Effect of Parcel Map Over IBC Defaults 1-D Amplification Used in IBC, ShakeMap 3-D Amplification from ShakeZoning J. Louie, NESC 2/9/2011

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 J. Louie, NESC 2/9/2011

Frenchman Mountain Fault M6.7 Scenario Possible Scarp in Neighborhood Event Inside the LVV Basin J. Louie, NESC 2/9/2011

2-Segment Frenchman Mtn. Fault M6.7 J. Louie, NESC 2/9/2011

Effect of Parcel Map Over IBC Defaults J. Louie, EGGE 3/25/2011

With Many Scenarios, Define Probabilistic Hazard J. Louie, EGGE 3/25/2011  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.

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