Next-Level ShakeZoning for Next-Level ShakeZoning for Earthquake Hazard DefinitionEarthquake Hazard Definition

in the Intermountain Westin the Intermountain West

John N. LouieJohn N. Louie, , Will Savran, Brady Flinchum, Will Savran, Brady Flinchum, Gabriel Plank, Graham Kent, Kenneth D. SmithGabriel Plank, Graham Kent, Kenneth D. Smith

Nevada Seismological LaboratoryNevada Seismological Laboratory

Satish K. Pullammanappallil, Aasha PanchaSatish K. Pullammanappallil, Aasha Pancha

Optim Seismic Data SolutionsOptim Seismic Data Solutions

Werner K. HellmerWerner K. Hellmer

Clark County Dept. of Development ServicesClark County Dept. of Development Services

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Next-Level ShakeZoningNext-Level ShakeZoning Goal is to predict earthquake shakingGoal is to predict earthquake shaking

For hazard mapping, planningFor hazard mapping, planning Building-code development and enforcementBuilding-code development and enforcement Emergency responseEmergency response

USGS ShakeMapUSGS ShakeMap Based on statistical averages; sparse dataBased on statistical averages; sparse data Most data came from California, Japan, TaiwanMost data came from California, Japan, Taiwan

Next-Level ShakeZoning Next-Level ShakeZoning for Nevadafor Nevada Based on: Wave PhysicsBased on: Wave Physics Geological & Geotechnical data from the IMWGeological & Geotechnical data from the IMW Validating against Nevada earthquake recordsValidating against Nevada earthquake records

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Clark County & Henderson Parcel MapClark County & Henderson Parcel Map

10,721 Measurements10,721 Measurements Urban Areas of CountyUrban Areas of County

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Clark County Clark County & Henderson & Henderson Parcel MapParcel Map

Parcel Parcel Classification Classification

for IBCfor IBC

NEHRP NEHRP CC & & DD classesclasses

““C+C+” class for ” class for NEHRP B NEHRP B

velocities with velocities with soft surfacesoft surface

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Build Parcel Build Parcel Map into Map into

ShakeZoningShakeZoning

ShakeZoning ShakeZoning Geotech MapGeotech Map

Warmer colors: Warmer colors: lower Vs30 (meter)lower Vs30 (meter)

Parcel Map on top Parcel Map on top of IBC default Vs30of IBC default Vs30

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Adding Fault and Basin GeologyAdding Fault and Basin GeologyBlack Hills Fault in Google Black Hills Fault in Google Earth with USGS Qfaults Earth with USGS Qfaults tracetrace

Langenheim Basin MapLangenheim Basin Map

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Adding PhysicsAdding Physics

Black Hills M6.5 eventBlack Hills M6.5 event Short trace but 4-m scarps Short trace but 4-m scarps

notednoted

Viscoelastic finite-Viscoelastic finite-difference solutiondifference solution

0.5-Hz frequency0.5-Hz frequency 0.20-km grid spacing0.20-km grid spacing A few hours on our small A few hours on our small

clustercluster

Mode conversion, rupture Mode conversion, rupture directivity, reverberation, directivity, reverberation, trapping in basinstrapping in basins

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Black Hills M6.5 Black Hills M6.5 Scenario ResultsScenario Results

Max Peak Ground Velocity Max Peak Ground Velocity (PGV) >140 cm/sec(PGV) >140 cm/sec

PGV over 60 cm/sec (PGV over 60 cm/sec (yellowyellow) ) bleeds into LVV through bleeds into LVV through Railroad PassRailroad Pass

Large event for a short faultLarge event for a short fault Unlikely, but add to hazard Unlikely, but add to hazard

probabilisticallyprobabilistically Need to know how unlikelyNeed to know how unlikely

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Surprising Effect of Parcel Map Over IBC DefaultsSurprising Effect of Parcel Map Over IBC Defaults

1-D Amplification Used in 1-D Amplification Used in IBC, ShakeMapIBC, ShakeMap

3-D Amplification from 3-D Amplification from ShakeZoningShakeZoning

J. Louie, NESC 2/9/2011J. Louie, NESC 2/9/2011

ShakeMap versus ShakeZoningShakeMap versus ShakeZoning•Yellow is 60 cm/sec on bothYellow is 60 cm/sec on both•Geotech estimated from topographyGeotech estimated from topography

•ShakeZoning shows trapping in basinsShakeZoning shows trapping in basins•Hazard map is difficult to predictHazard map is difficult to predict

J. Louie, NESC 2/9/2011J. Louie, NESC 2/9/2011

Frenchman Mountain Fault M6.7 ScenarioFrenchman Mountain Fault M6.7 ScenarioPossible Scarp in Possible Scarp in NeighborhoodNeighborhood

Event Inside the LVV BasinEvent Inside the LVV Basin

J. Louie, NESC 2/9/2011J. Louie, NESC 2/9/2011

2-Segment Frenchman Mtn. Fault M6.72-Segment Frenchman Mtn. Fault M6.7

J. Louie, NESC 2/9/2011J. Louie, NESC 2/9/2011

Effect of Parcel Map Effect of Parcel Map Over IBC DefaultsOver IBC Defaults

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

With Many Scenarios, Define Probabilistic HazardWith Many Scenarios, Define Probabilistic Hazard

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Recurrence Intervals:Recurrence Intervals: Black Hills- 15 kaBlack Hills- 15 ka Frenchman Mtn.- 45 kaFrenchman Mtn.- 45 ka

e.g., PGV at UNLV: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 Combine rates per annumper annum:: >15 cm/s at 0.0001 p.a.>15 cm/s at 0.0001 p.a. >20 cm/s at 0.00007 p.a.>20 cm/s at 0.00007 p.a.

With Many Scenarios, Define Probabilistic HazardWith Many Scenarios, Define Probabilistic Hazard

J. Louie, EGGE 3/25/2011J. Louie, EGGE 3/25/2011

Japan and New Zealand Lesson: Japan and New Zealand Lesson: Don’t Ignore Don’t Ignore Worst Case!Worst Case!

dePolo, 2008, NBMG Map 167dePolo, 2008, NBMG Map 167