“VVS 30S 30 - A Basis for Characterization of Seismic Site ifi R i l d Gl b lResponse for Site-specific, Regional, and Global

Mapping of Seismic Hazard

Roger D. Borcherdt

1st Annual Meeting of the Strategic Chinese-Korean-Japanese Cooperative Program:

Seismic Hazard Assessment for the Next Generation Map

November 25-30, 2011Harbin Institute of Technologya b st tute o ec o ogy

Harbin, China

borcherdt@usgs.gov

Outline• Definition VV• Definition VVS 30S 30

•• VVS 30S 30 as a Basis for Characterization of Site-Specific Site Responsep• Theoretical Dependence of Amplification on VVS 30S 30

• Empirical Dependence of Amplification on VVS 30S 30

•• VV correlations with VV at other depths S 30S 30 S ZS Z p

•• VVS 30S 30 as a Basis for Mapping Site ResponseCorrelations of VV with:Correlations of VVS 30S 30 with: • Physical Properties -- Site Class definitions• Geologic Age• Topographic Slope• Topographic Slope

• Applications of VVS 30S 30• Site-Specific Response Characterization – Site Classes, Site Coefficients, Building Codes • Regional Site Response Mapping – GMPEs, ShakeMaps, PSHA, GEM

VVS 30S 30 Definition

0

0 500 1000

S Velocity (m/s)

0

10

20

epth

(m)

30

40

De

40

(from Borcherdt, 1994)

Theoretical Response of a Viscoelastic Soil Layer versus Vs Ratio and Normalized Fre uencq y

Amplitude Response versus FrequencyHomogeneous Linear S Wave, Vertical Incidenc

DRQ2 = 0.02 RQ1 = 2 DR = 0.1

1

1HsQ −0D

2θ2γ

2D 2

1HsQ −

1Hsv2Hsv

SoilSoil

8

2γRockRock

DSolution:

0.8

1

2

4

6

8

0

1

0

F[ . . . ]

F[ ),( )]1Hs -1 -1 12 2 Hs Hs

D (inc wave field par ),(material par )D

vD f( , , ,Q ,Q ,ρθ

=

=2 0.4

0.62

2 1

2

Hs

Hs

vv

f1 0

0

[ ),( )]

where =fundamental frequency.

1 2

2

2 2 Hs HsHs 2

( , , ,Q ,Q ,D f v

f

γρ 4

6

0.24

6

2

0

ff

Empirical Spectral Amplification Values versus VVS 30S 30ILoma Prieta Earthquake; Ia < 0.1g

100

catio

n

Short-Period Band (0.1 -0.5 s)(997 / 0.36

100

catio

n

Intermediate-Period Band (0.5 - 1.5 s)0.69

1

10

Spec

tral A

mpl

ific ___ F = (997 m/s / v) 0.36

...... 95% Confidence Limits for Ordinate--- + 2 Standard Error of Estimate

1

10

Spec

tral A

mpl

ific ___F = (1084 m/s / v)

...... 95% Confidence Limits for Ordinate--- + 2 Standard Error of Estimate

0.1100 1000

Mean Shear-Wave 30 (100 t v m/s)

Ave

rage

S

(a)0.1

100 1000

Shear-Wave l 30 (100 ft)

Ave

rage

(b)

Mean Shear-Wave Velocity to 30 m (100 ft) (v , m/s) Mean Shear Wave Velocity to 30 m (100 ft) (v, m/s)

10

100

mpl

ifica

tion

Mid-Period Band (0.4 - 2.0s)___ F = (1067 m/s / v)0.64

...... 95% Confidence Limits for Ordinate+ Standard of10

100

Am

plifi

catio

n

Long-Period Band (1.5 - 5.0s)___F = (1077 m/s / v)0.67

...... 95% Confidence Limits for Ordinate+ Standard of

1

erag

e Sp

ectra

l Am

(d)

--- + 2 Standard Error of Estimate

1

vera

ge S

pect

ral A

--- + 2 Standard Error of Estimate

0.1100 1000

Mean Shear-Wave Velocity to 30 m (100 ft) (v, m/s)

Ave (d)

0.1100 1000

Mean Shear-Wave Velocity to 30 m (100 ft) (v, m/s)

Av (c)

(Borcherdt, 1994)

Empirical Spectral Amplification Values versus VVS 30S 30Northridge Earthquake; Ia < 0.2g, Ia > 0.2g

Empirical Dependence of Amplification on Empirical Dependence of Amplification on VVS 30S 30(Site Coefficients for Seismic Design)(Site Coefficients for Seismic Design)

ShortShort-- and Midand Mid--Period Amplification Factors are:Period Amplification Factors are:mmmma a

FFa a = (V= (Vref ref / V/ VS 30S 30 ) )

andand mmand and mmvvFFvv = (V= (Vref ref / V/ VS 30S 30 ))

where,where,

1) 1) VVS 30S 30 is inferred or measured mean shearis inferred or measured mean shear--wave velocity to 30 m at site,wave velocity to 30 m at site,

2) 2) VVref ref is is VVS 30S 30 for reference ground condition,for reference ground condition,

3) 3) mma a and and mmvv depend on input ground motion level.depend on input ground motion level.

Fa versus Input Amplitude & VVS 30S 30Ia = 0.1, 0.2, 0.3, 0.4 g (linear scales)

5

b

4

a w

rt S

C-I

b

I=0.1g; ma = 0.35= 2g; =

Fa = (v SC-Ib / v ) m a = ( 1050 m/s / v) m a

SC-IV

3

plifi

catio

n Fa I 0.2g; ma 0.25

I=0.3g; ma = 0.10I=0.4g; ma = -0.05Fa (0.1g) for Site Class Intervals

for

Soft soils

SC-IISC-III

Stiff clays and

1

2

Perio

d A

mp Fa for Site ClassesGravelly soils and

Soft rocks Firm to Hard rocks

SC-IbSandy soils

0100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Shor

t-P

(a)

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mean Shear-Wave Velocity to 30 m (100 ft) (v , m/s)(Borcherdt, 1994)

Fv versus Input Amplitude & VVS 30S 30I (li l )Iv = 0.1, 0.2, 0.3, 0.4 g (linear scales)

5SC IV

4

wrt

SC-I

b

I=0.1g; mv = 0.65I=0.2g; mv = 0.60

Soft soilsSC-IV

SC-III

Fv = (v SC-Ib / v ) m v = ( 1050 m/s / v) m v

3

lific

atio

n Fv g;

I=0.3g; mv = 0.53I=0.4g; mv = 0.45Fv(0.1g) for Site Class IntervalsFv for Site Classes

Stiff clays andSandy soils

Gravelly soils and SC-II

1

2

Perio

d A

mpl f

Soft rocks

Firm to Hard rocksSC-Ib

0100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mid

-P

(b)

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mean Shear-Wave Velocity to 30 m (100 ft) (v , m/s)(Borcherdt, 1994)

NEHRP & NGA Short-Period Amplification versus VVS 30S 30Aa=0.1g; Avg. 0.1-0.5s; Vs30 norm 1050 m/s

NEHRP & NGA Mid-Period Amplification versus VVS 30S 30Av = 0.1g; Avg. 0.4-2.0 s; Vs30 norm 1050 m/s

VVS 30S 30 Correlation with VVS Z S Z at other Depths

VVS 30S 30 as a function of as a function of VVS ZS Z at another depth:at another depth:

Log[VLog[VS 30S 30 ] = c] = c0 0 + c+ c1 1 Log[VLog[VS ZS Z] = G(V] = G(VS ZS Z ) ) (Cadet et al(Cadet et al 2009;2009; BooreBoore et alet al 2011)2011)(Cadet, et al., (Cadet, et al., 2009; 2009; BooreBoore, et al., , et al., 2011)2011)

Hence, amplification as a function of Hence, amplification as a function of VVS 30S 30 ::mmaaa a

FFa a = (= (VVS 30 ref S 30 ref / V/ VS 30S 30 ) = F) = Fa a (V(VS S 30 ref30 ref , VS 30 ))

Implies amplification as a function of Implies amplification as a function of VVS ZS Z at at other depths:other depths:

FFa a = H= Ha a ((VS Z ref ,,VS Z))

VVS 30S 30 as a Basis for Mapping Site Response

Correlations of VV with: S 30S 30

Physical Properties -- Site Class definitions

Geologic Age

Topographic Slope

VVS 30S 30 for USGS Boreholes in CA

1400

Vs30 for USGS Boreholes in CA

1000

1200

e Cl

ass

B

800

1000

loci

ty -

Site

400

600

Shea

r Ve

C

0

200

DE

Borehole Locations

VVS 30S 30 versus Physical Property Classification for USGS Boreholes in CASuggests Seismically Distinct UnitsSuggests Seismically Distinct Units

1400Texture,Fracture Spacing & Age Classification for USGS Boreholes in CA

1200

Clas

s

KJs, grNEHRP CSoils Soft

NEHRP BFirm to Hard Rock

gr, Kjs w ide fractures

800

1000

ocity

- Si

te C

Ts TvQyc/QomKJs, gr

gr w fs

w f sGravelly Soils and Soft Rock Qym/Qoc, Qom, Qyc/ Qoc, Qyc Soils

Ts, Tv, KJs, gr Close Fractures

NEHRP

B

400

600

Shea

r Vel

o

Q

QomQyc

Ts,Tv, .c fsNEHRP D

Stiff Clays and Sandy Soils Qyf, Qym, Qof, Qom-Qof

Qom-Qyf

Qyc/Qom c fsNEHRP ESoft Soilsaf/ QhbmC Qym/Qoc

0

200

Qym Qofaf/Qhbm QyfDE

0Boreholes

VVS 30S 30 Statistics for Physical Property Classification (Texture, Fracture Spacing, & Age -- USGS Boreholes in CA)

Statistics for Texture, Fracture Spacing, Age Classification of USGS Boreholes in CA

1400

1000

1200

1400

(m/s

) Mean + S D.Mean

600

800

1000

ve V

eloc

ity

ite C

lass

Mean - S.D.B

200

400

600

Shea

r Wav Si C

D

0

200

bm Qyf ym Qof oc om Qyc Tv ) gr s)E

Qhbm Qy

Qym QoQym

/Qoc

Qom QyTs &

TvKJs (

close

f s) g

KJs (wide f

s)

Physical Property Classes

Vs30 Statistics for Physical Property NEHRP Site Classes (Texture, Fracture Spacing, & Age -- USGS Boreholes in CA)

f rac ur S Cla ificationStatistics for Texture/Age, Fracture Spacing/Age Classification of USGS Boreholes in CA (NEHRP Boundaries)

1400Mean + S D.MeanMean

1000

1200

city

(m/s

)s

Mean - S.D.

B

600

800

Wav

e Ve

loc

Site

Cla

ssC

200

400

Shea

r W

DE

0af/Qhbm Qyf, Qym, Qof Qym/Qoc, Qom, Qyc,

Ts, Tv, KJs c f s gr, Kjs w f s

(from Borcherdt, 1994)

Geologic Site Condition Map (VVS 30S 30 correlations with Geologic Age)

Wills et al., 2000

CGS Geologic Classification versus VVS 30S 30

1400CGS Classification for USGS Boreholes in CA

1000

1200

Site

Cla

ssB

E DE D CD C CB B

600

800

s) -

NEH

RP

400

600

eloc

ity (m

/s C

0

200

Shea

r Ve

DE

0

Borehole

VVS 30S 30 Correlations with Topographic Slope

Active Tectonic Regions St bl C ti t l R iActive Tectonic Regions Stable Continental Regions

(from Wald and Allen, 2007)

VVS 30S 30 Map(Derived from Topographic Slope)

Vs30 (topographic slope) Topographic Relief (elevation)

VVS 30S 30 Maps(Derived from Geologic Age and Topographic Slope)(Derived from Geologic Age and Topographic Slope)

Vs30 (geologic age) Vs30 (topographic slope)

(Wald and Allen, 2007)

Applications of VVS 30S 30

• Site-Specific Response Characterization• Site Classes & Site Coefficients for Site-specific Design SpectraSite Classes & Site Coefficients for Site-specific Design Spectra,

Building Codes • Ground Motion Prediction Equations (GMPE) developed as

continuous function of Vs30continuous function of Vs30

• Re ional Site Res onse Map in g p pp g• ShakeMaps• PSHA Maps• Global Earth uake Model GEMq ( )

Definition of SiteDefinition of Site--Dependent Respons e Dependent Response Spectra (log(log--log scale)log scale)

(NEHRP, UBC, IBC, ASCE 7 Provisions)(NEHRP, UBC, IBC, ASCE 7 Provisions)

1

on S

A (g

)A

ccel

erat

io

I a Fa0.1

se S

pect

ral

x

a

Fv

0.01

Res

pons I v / T

x

0.1 1 10

Period (secs)

SiteSite--Dependent Response SpectraDependent Response Spectra (linear(linear--linear scale)linear scale)(NEHRP UBC IBC ASCE 7 Provisions)(NEHRP UBC IBC ASCE 7 Provisions)(NEHRP, UBC, IBC, ASCE 7 Provisions)(NEHRP, UBC, IBC, ASCE 7 Provisions)

D S DS

2 23 3a a a DS MS

Sa

SS I F S ST

F⎛ ⎞= = = = ⎜ ⎟⎝ ⎠

D

0

n Sa

(g)

23a SI S=

1 112 2

3 3v

a v D M vS FIS F S S

T T⎛ ⎞= = = = ⎜ ⎟⎝ ⎠

3 3 T⎝ ⎠

0

0

e A

ccel

erat

io

S D1

3 1 13 3a v D M vT T⎜ ⎟⎝ ⎠

( ): LS T T S TT ⎛ ⎞≥ = ⎜ ⎟

0

tral R

espo

nse

123

vI ST T=

( ) 1 2: La DS T T ST

T ≥ = ⎜ ⎟⎝ ⎠

0Spec

t

Period T (secs)

T 0 T S 1 T L

Fa versus Input Amplitude & VVS 30S 30Ia = 0.1, 0.2, 0.3, 0.4 g (linear scales)

5

b

4

a w

rt S

C-I

b

I=0.1g; ma = 0.35= 2g; =

Fa = (v SC-Ib / v ) m a = ( 1050 m/s / v) m a

SC-IV

3

plifi

catio

n Fa I 0.2g; ma 0.25

I=0.3g; ma = 0.10I=0.4g; ma = -0.05Fa (0.1g) for Site Class Intervals

for

Soft soils

SC-IISC-III

Stiff clays and

1

2

Perio

d A

mp Fa for Site ClassesGravelly soils and

Soft rocks Firm to Hard rocks

SC-IbSandy soils

0100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Shor

t-P

(a)

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mean Shear-Wave Velocity to 30 m (100 ft) (v , m/s)(Borcherdt, 1994)

Fv versus Input Amplitude & VVS 30S 30I (li l )Iv = 0.1, 0.2, 0.3, 0.4 g (linear scales)

5SC IV

4

wrt

SC-I

b

I=0.1g; mv = 0.65I=0.2g; mv = 0.60

Soft soilsSC-IV

SC-III

Fv = (v SC-Ib / v ) m v = ( 1050 m/s / v) m v

3

lific

atio

n Fv g;

I=0.3g; mv = 0.53I=0.4g; mv = 0.45Fv(0.1g) for Site Class IntervalsFv for Site Classes

Stiff clays andSandy soils

Gravelly soils and SC-II

1

2

Perio

d A

mpl f

Soft rocks

Firm to Hard rocksSC-Ib

0100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mid

-P

(b)

100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400

Mean Shear-Wave Velocity to 30 m (100 ft) (v , m/s)(Borcherdt, 1994)

Short-Period Site Coefficient FShort Period Site Coefficient Fa (NEHRP, UBC, IBC, AASHTO, ASCE 7 Provisions)(NEHRP, UBC, IBC, AASHTO, ASCE 7 Provisions)

Site Aa < 0.1 Aa = 0.20 Aa = 0.30 Aa = 0.40 Aa > 0.50

Class Ss < 0.25 Ss = 0.50 Ss = 0.75 Ss = 1.00 Ss > 1.25

A 0.8 0.8 0.8 0.8 0.8

B 1.0 1.0 1.0 1.0 1.0

C 1.2 1.2 1.1 1.0 1.0

D 1.6 1.4 1.2 1.1 1.0

E 2.5 1.7 1.2 0.9 *

F * * * * *

* Site-specific geotechnical investigation and dynamic site response analysis shall be performedperformed.

Mid-Perio Site Coefficient FMid Period Site Coefficient Fv(NEHRP, UBC, IBC, AASHTO Provisions)(NEHRP, UBC, IBC, AASHTO Provisions)

Site Av < 0.1 Av = 0.20 Av = 0.30 Av = 0.40 Av > 0.50

Class Sl < 0.1 Sl = 0.20 Sl = 0.30 Sl = 0.40 Sl > 0.50

A 0.8 0.8 0.8 0.8 0.8A 0.8 0.8 0.8 0.8 0.8

B 1.0 1.0 1.0 1.0 1.0

C 1.7 1.6 1.5 1.4 1.3

D 2.4 2.0 1.8 1.6 1.5

E 3.5 3.2 2.8 2.4 *

F * * * * *

* Site-specific geotechnical investigation and dynamic site response analysis shall be Site-specific geotechnical investigation and dynamic site response analysis shall be performed.

Response versus Period, Shear Velocity, and Code Site Class

RQ2 = 0.02 RQ1 = 2 DR= 0.1

Anelastic Soil LayerDamping Ratio 5%Vertical Incidence

SoilSoilRockRock 0.8

1

2

4

0.5 0.4

0.6

0.5 1

2

Hs

Hs

vv

1

1.5

2

0.2

1

1.5

20

TT

Code Site Coefficients and Theoretical Response 15 % Damping or I 4Response 15 % Damping or Ia~ 0.4 g

RQ2 = 0.02 RQ1 = 2 DR= 0.3

Anelastic Soil LayerDamping Ratio 15 %

Ia ~0.4 gVertical IncidenceVertical Incidence

3 Fv BFv BFv B

SoilSoilRockRock 0.8

1

1

2Fv EFv EFv E Fv DFv DFv D

Fv CFv CFv C

0.5

10.4

0.6

0.5

1

22

1

1.5

2

0.2

1

1.5

2

0

TT

NGA Ground Motion Prediction EquationsGMPE = f (VVS 30S 30 )

GMPE

ln mag dis styleof faulting site sedY f f f f f ε= + + + + +

( )VfWhere, site condition term = ( )30site SVf

[ ]30 30ln ln ln ;n

S Sc k A c A c kV V V⎧ ⎫⎡ ⎤⎛ ⎞ ⎛ ⎞⎪ ⎪⎢ ⎥+ +⎨ ⎬⎜ ⎟ ⎜ ⎟

⎧ ⎫⎪ ⎪[ ]

( )

30 3030

30

10 2 1100 1100 11 1

ln ln ln ;

ln ; 1100

S SS

S

c k A c A c kk k

f c k n k V

V

V

⎢ ⎥+ + = + <⎨ ⎬⎜ ⎟ ⎜ ⎟⎢ ⎥⎝ ⎠ ⎝ ⎠⎪ ⎪⎣ ⎦⎩ ⎭

⎛ ⎞= + ≤ <⎜ ⎟

⎪ ⎪⎪ ⎪⎪ ⎪⎪ ⎪⎪ ⎪⎨ ⎬( )

( )

3010 2 11

10 2

ln ; 1100

1100ln

site Sf c k n kk

c

V

nk

= + ≤ <⎜ ⎟⎝ ⎠⎛ ⎞

+ ⎜ ⎟ 30 ; 1100SV

⎨ ⎬⎪ ⎪⎪ ⎪⎪ ⎪≥⎪ ⎪( )10 2

1k⎜ ⎟⎝ ⎠

30; S⎪ ⎪⎪ ⎪⎩ ⎭

(from Campbell and Bozorgnia, 2004)

VVS 30S 30 for Regional Site Response Mapping

ShakeMaps

VVS 30S 30 Map (Topographic Slope)(San Francisco Bay Region)(San Francisco Bay Region)

http://earthquake.usgs.gov/hazards/apps/vs30/

Spectral Acceleration ShakeMaps Loma Prieta EarthquakeLoma Prieta Earthquake(San Francisco Bay Region)

Spectral Acceleration 0.3 Sec Spectral Acceleration 1.0 Sec

http://earthquake.usgs.gov/hazards/apps/

Instrumental Intensity ShakeMap Loma Prieta Earthquakeq(San Francisco Bay Region)

http://earthquake.usgs.gov/hazards/apps/

VVS 30S 30 Map (Topographic Slope)(Haiti Region)(Haiti Region)

http://earthquake.usgs.gov/hazards/apps/vs30/

Spectral Acceleration ShakeMaps Tohoku Japan Earthquake M 9 0)Tohoku Japan Earthquake M 9.0)

(Honshu Japan Region)

Spectral Acceleration 0.3 Sec Spectral Acceleration 1.0 Sec

http://earthquake.usgs.gov/hazards/apps/

Instrumental Intensity ShakeMap Haiti Earthquake M 7 0)Haiti Earthquake M 7.0)

http://earthquake.usgs.gov/hazards/apps/

VVS 30S 30 for Seismic Hazard and Risk Mapping

• PSHA Maps

• GEM Global Seismic Hazard Mapping Project• GEM Global Seismic Hazard Mapping Project

VVS 30S 30 Map (Topographic Slope)(Western US)(Western US)

PSHA Map for Rock (NGA GMPE 2008 SA @2 s, 2% PE 50 yr, VVS 30S 30 = 760 m/s)= 760 m/s)

PSHA Map Including Site Conditions (VVS 30S 30)(SA @1 s, 2% PE 50 yr))

(Kalkan and Grazier, 2010)

Global GMPE for GEM (Si di i h i i b d VV )(Site condition characterization based on VVS 30S 30 )

Bozorgnia and others, 2011

ConclusionsTh ti l d l d i i l t h VV hh• Theoretical models and empirical measurements show VVS 30S 30 shows a shows a strong correlation with amplification, Fa and Fv, at specific sites.strong correlation with amplification, Fa and Fv, at specific sites.

•• Correlations of Correlations of VVS ZS Z with VVS 30S 30 implyimply VVS ZS Z at other depths can be used to at other depths can be used to didi VV d lifi i F d Flifi i F d Fpredict predict VVS 30S 30 and amplification, Fa and Fv.amplification, Fa and Fv.

•• Correlations of Correlations of VVS 30S 30 with Physical Properties, Geologic Age, and with Physical Properties, Geologic Age, and Topographic Slope imply Topographic Slope imply VVS 30S 30 can be mapped on regional and global can be mapped on regional and global scales. scales.

•• Hence, Hence, VVS 30S 30 serves as a useful basis for characterization of site response serves as a useful basis for characterization of site response for specific sites and for regional mapping purposes for the appropriate for specific sites and for regional mapping purposes for the appropriate applications.applications.

•• Important applications of Important applications of VVS 30S 30 include:include:–– Unambiguous definitions of site classes and site coefficients for routine design Unambiguous definitions of site classes and site coefficients for routine design

in building codes in building codes –– Characterization of site response for GMPEs for use in Site Specific, Characterization of site response for GMPEs for use in Site Specific,

Regional, and Global Mapping of Seismic Hazard for appropriate Regional, and Global Mapping of Seismic Hazard for appropriate i t t tii t t ti Sh k MSh k M PSHA M GEM M d lPSHA M GEM M d linterpretations: interpretations: ShakeMapsShakeMaps, PSHA Maps, GEM Model, PSHA Maps, GEM Model

borcherdt@usgs.gov