INGV-DPC S4 riunione Siena 28-29 Aprile 2010 ITACA the Italian strong-motion database Task5 – site...

INGV-DPC S4 riunione Siena 28-29 Aprile 2010

ITACA

the Italian strong-motion database

Task5 – site classification

INGVINGV

R. Paolucci, S. GiorgettiPolitecnico di Milano (POLIMI)

L. Luzi, F. Pacor, R. Puglia, M. Massa, D. Bindi Istituto Nazionale di Geofisica e Vulcanologia (INGV)

M. R. Gallipoli, M. Mucciarelli Università della Basilicata


Analysis descriptionAnalysis description

• The performance of different classification schemes has been tested through the evaluation of GMPEs

• The GM is represented by the acceleration response spectra ordinates (5% damping)

• The response variables are: magnitude, distance, style of faulting and soil classes

• A GMPE is derived for each classification

• The GMPE performance has been evaluated in terms of standard deviation of the GMPEs and of the errors associated to the classes of each scheme


Response variable: SA (5%, 0.04≤T≤ 4sec) Geomean of H components

Functional form (e.g. Akkar & Bommer, 2007):

Functional form for regressionFunctional form for regression

jjii FfSeRgMfaY )(log10

refJBrefJBrefW RhRkRhRMMccRg 2222

1021 /log)(

221)( refWrefW MMbMMbMf

Mref = 5.6, Rref = 1km


Regression approachRegression approach

ikiikikiik FSRMY );,,,(log10 x

ikkikikiik FSRMY ');,,,(log10 x

222recrecstaeve

Random effect model (e.g. Brillinger & Preisler, 1985):

Inter-event (i)

Inter-station (k)

Inter-event error = error due to an earthquake recorded by many stations

Inter-station error = error due to a station which recorded several events


ikiSikiikik VRMy 30,....,,Mean prediction

Earthquake i recorded at station k

Inter-event distribution of error : it assumes a value for each earthquakeand describes the correlation among the errors for different recordings of the

same earthquake. It is a normal distribution with standard deviation equal to

Error distributionsObservation

Intra-event distribution of error : it assumes a value for each recording.

It is a normal distribution with standard deviation equal to . The error distributions and are assumed to be independent.

RANDOM EFFECT MODELRANDOM EFFECT MODEL inter/intra - eventinter/intra - event


ikiSikiikik VRMy 30,....,,Mean prediction



ikiSikiikikik VRMysidual 30,....,,Re

The residuals are decomposed as the sum of the inter- and intra-event error distributions

Since the distributions are independent, the total variance is the sum of the two variances:

222 tot

RANDOM EFFECT MODELRANDOM EFFECT MODEL inter/intra - eventinter/intra - event


Inter/intra – event errorInter/intra – event error


ikkSikiikik VRMy '30,....,,

Mean prediction


Inter-station distribution of error : it assumes a value for each stationand describes the correlation among the errors for different recordings at the

same station. It is a normal distribution with standard deviation equal to


Intra-station distribution of error ’: it assumes a value for each recording.

It is a normal distribution with standard deviation equal to ’. The error distributions and ’ are assumed to be independent.

RANDOM EFFECT MODELRANDOM EFFECT MODEL inter/intra - stationinter/intra - station


Example of ITACA , SA at T=1.75 sExample of ITACA , SA at T=1.75 s

222 ' tot

Bindi et al, 2010

Recordings ik%

Recordings ik

Stations k%

k

’ik

Residualik

k

’ik

=

+

Error distributions

tot2=0.16763

2=0.05867

’2=0.10896

=

+

variances

ikkSikiikikik VRMysidual '30,....,,Re


Bindi et al, 2010

CLC

AVZ

Different earthquakes with magnitude 5.5±0.2 recorded at GBP

GBP

Model for ITACA (black): mean prediction for a M=5.5, class C - EC8




Bindi et al, 2010

GBP


CLC

AVZ

GBPInter-station errorfor GBP

CLC

AVZ nearly zero

Red curve=Mean GMPE + inter-station error for GBP



Bindi et al, 2010

GBP


CLC

AVZ

GBPInter-station errorfor GBP

Intra-station errorfor event i recordedat GBP

’GBP,i




Different earthquakes with magnitude 5.5 ± 0.4 recorded by different class C stations

Red curve=Mean + inter-station standard deviation

Blue curve=Mean + intra-station standard deviation

Dashed curve=Mean + total standard deviation




Classification schemes: EC8Classification schemes: EC8

Subsoil class

Description of stratigraphic profile Parameters

Vs,30

(m/s)

NSPT (bl/30cm) cu (kPa)

A Rock or other rock-like geological formation, including at most 5m of weaker material at the surface

800 _ _

B Deposits of very dense sand, gravel, or very stiff clay, at least several tens of m in thickness, characterised by a gradual increase of mechanical properties with depth

360 – 800

50 250

C Deep deposits of dense or medium-dense sand, gravel or stiff clay with thickness from several tens to many hundreds of m

180 – 360

15 - 50 70 – 250

D Deposits of loose-to-medium cohesionless soil (with or without some soft cohesive layers), or of predominantly soft-to-firm cohesive soil

180 15 70

E A soil profile consisting of a surface alluvium layer with Vs,30

values of class C or D and thickness varying between about 5 m and 20 m, underlain by stiffer material with Vs,30 > 800 m/s

S1 Deposits consisting – or containing a layer at least 10 m thick – of soft clays/silts with high plasticity index (PI 40) and high water content

100(indicative)

_ 10 – 20

S2 Deposits of liquefiable soils, of sensitive clays, or any other soil profile not included in classes A –E or S1


based on Vs,30 when available (~ 80 stations at the present time)

ORbased on an expert evaluation when Vs,30 is not available, account for:

• detailed geology and stratigraphic profiles when available• H/V from noise and/or earthquake data• 1:100,000 lithologic map

ITACA - EC8ITACA - EC8

B

A

CD E


Classification schemes: Sabetta & Pugliese (1987)Classification schemes: Sabetta & Pugliese (1987)

Based on geological and geotechnical information and the thickness H of the soil layer, three categories:

•Rock sites

•Stiff, shallow alluvium (H =< 20 m)

•Deep alluvium (H > 20 m)

Stiff sites have average shear-wave velocity greater than 800 m/s

alluvium sites have a shear-wave velocity between 400 and 800 m/s


Classification schemes: Rovelli et al. (2008)Classification schemes: Rovelli et al. (2008)

ZHAO et al. (2006)ZHAO et al. (2006) FUKUSHIMA et al. (2007)FUKUSHIMA et al. (2007)

PERIOD T (sec)PERIOD T (sec)CAT.CAT.

SCISCISCIISCIISCIIISCIIISCIVSCIV

T < 0.2T < 0.20.2 <= T < 0.2 <= T < 0.40.40.4 <= T < 0.60.4 <= T < 0.6T >= 0.6T >= 0.6

PERIOD T (sec)PERIOD T (sec)CAT.CAT.

SC1SC1SC2SC2SC3SC3SC4SC4

T < 0.2T < 0.20.2 <= T < 0.60.2 <= T < 0.6T >= 0.6T >= 0.6

SC5SC5 Generic SoilGeneric Soil

Generic RockGeneric Rock

JAPAN ROAD ASSOCIATION

Rovelli et al.Rovelli et al.

CAT.CAT.

SCISCISCIISCIISCIIISCIIISCIVSCIV

T < 0.2T < 0.2

T >= 0.6T >= 0.6

PERIOD T (sec)PERIOD T (sec)

0.2 <= T < 0.2 <= T < 0.40.40.4 <= T < 0.60.4 <= T < 0.6

SCVSCVSCVISCVISCVIISCVII UnknownUnknown

T unknown & orig. AB siteT unknown & orig. AB siteT unknown & orig. CD siteT unknown & orig. CD site

based on predominant period of H/V SA ratios


Classification based on fClassification based on f00-Vs,-Vs,3030

• Based on Vs,30 and fundamental frequency of the site, evaluated through H/V of acceleration response spectra

• 3 classes are individuated on the base of cluster analysis

• Sites are assigned to a class on the base of the membership degree


Mean f0 Std f0

C1 1.27 0.43

C2 2.48 1.65

C3 4.70 2.14

C1

C2

C3

Mean Vs30 Std Vs30

C1 255.77 58.96

C2 426.70 48.96

C3 605.11 71.11

Cluster analysis: the error of each cluster is calculated as the mean point – to – centroid distance (normalized to the standard deviation of the cluster)

Cluster analysisCluster analysis


C1

C2

C3

Degree of membership to a classDegree of membership to a class


C1

C2

C3

Cluster analysis (one variable)Cluster analysis (one variable)

Degree of membership to a class

Mean f0 Std f0

C1 1.13 0.53

C2 3.23 0.87

C3 7.08 1.44


Degree of membership to a classDegree of membership to a class

• Assuming that the variables of the points in a cluster are normally distributed, the membership to a soil class can be evaluated as probability density

• For a normal distribution of one variable, the probability density function is:

2

2)(

2

1

22

1)(

x

exf is the variable mean

The assigned class is the one with the highest probability

is the standard deviation


3

3.5

4

4.5

5

5.5

6

6.5

7

0.1 1 10 100 1000

Rjb [km]

M

Data set for regressionData set for regression

Magnitude range 3.5 – 6.3

Distance range 0 – 300 km

A common data set of

1000 records


fmax Num StazClasse I 26Classe II 36Classe III 18Classe IV 27Classe V 22Classe VI 19Classe VII 30

EC8 Num StazClasse A 89Classe B 46Classe C 34Classe D 3Classe E 6

SP Num StazClasse SP0 79Classe SP1 48Classe SP2 51

fzero Num StazClasse 1 49Classe 2 47Classe 3 27Classe 4 55

Number of stations for each class Number of stations for each class

= rock sites


Soil coefficientsSoil coefficients

0.01 0.1 1 10T [s]

0

0.2

0.4

0.6

0.8

1S4-MI

cl_1cl_2cl_3

0.01 0.1 1 10T [s]

0

0.2

0.4

0.6

0.8

1EC8

cl_Bcl_Ccl_Dcl_E

0.01 0.1 1 10T [s]

0

0.2

0.4

0.6

0.8

1SP96

S 1S 2

0.01 0.1 1 10T [s]

-0 .4

0

0.4

0.8

ROVcl_ Icl_ IIcl_ IIIc l_ IVC L_VI

C L_VII


Preliminary considerationsPreliminary considerations

• SP96 has 2 soil classes, therefore the soil coefficients tend to smooth the behaviour of peculiar sites. The classification is efficient, as the curves are clearly separated.

• EC8 has 4 soil classes, 2 classes represent sites with well defined response (classes D and E), while classes B and C tend to be very similar at low periods

• ROV has 6 soil classes, 2 have well defined response (classes 1 and 4), classes 2 and 3 have intermediate response, but they are too similar (0.2 - 0.4s and 0.4–0.6 s), coefficients of classes 6 and 7 also tend to be very similar (problem in class attribution?)

• S4-MI has 3 soil classes, each one with a well defined response.


GMPE GMPE tottot

0.30

0.32

0.34

0.36

0.38

0.40

0.42

0.44

0.46

0.48

0.50

0.01 0.1 1 10T[s]

To

tal

SP96

EC8

ROV

UR-MI

UR-MI5

No class

soil/rock


GMPE GMPE stasta

0.20

0.22

0.24

0.26

0.28

0.30

0.32

0.34

0.36

0.38

0.40

0.01 0.1 1 10

T[s]

inte

rsta

tio

n

SP96

EC8

ROV

UR-MI

UR-MI5

No class

soil/rock


Preliminary considerationsPreliminary considerations

• T (0.04-1s): SP96 EC8 and ROV have similar total standard deviations, S4-MI has lowest

• T>1s: EC8 is the classification with the lowest standard deviation, and it depends on the fact that 2 classes amplify the GM, class D (but represented only by 3 stations…..) and C

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.01 0.1 1 10

T[s]

Co

effi

cien

t

BCDE

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.01 0.1 1 10

T[s]

Co

effi

cien

t

Class1Class2Class3


Error distribution Error distribution for each class for each class (SP96)(SP96)

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts

F it 3 : N orm alN um ber o f data po in ts used = 79Average X = 0 .0224558S tandard D evia tion = 0 .248882

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts

F it 3 : N orm alN um ber o f data po in ts used = 48Average X = -0 .00503451S tandard D evia tion = 0 .361253

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5fr

equ

enc

y (%

)T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


0

1

2

Sigma >= 0.3


Error distribution Error distribution for each class for each class (EC8)(EC8)

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


A

B

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


C


Error distribution Error distribution for each class for each class (MI)(MI)

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5fr

equ

ency

(%

)T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


1

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


2


Error distribution Error distribution for each class for each class (MI)(MI)

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0.5s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

fre

que

ncy

(%)

T=0s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.1s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.2s

F it R esu lts


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=0.5s

F it R esults


-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=1.0s

F it R esu lts

F it 3 : N orm alN um ber o f data po in ts used = 55Average X = 0 .0456714S tandard D eviation = 0 .224521

-0.8 -0.4 0 0.4 0.8

0

0.1

0.2

0.3

0.4

0.5

freq

uen

cy (

%)

T=2.0s

F it R esu lts


3

4


A new soil class A new soil class Sites with broad band amplification: multiple peaks and average amplitude greater than 2.7 for a wide frequency range

FHCLNS

MNF

GRR

2.5

AQG

PSC

Rock sites=38

?


Performance Performance

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.01 0.1 1 10

T[s]

Co

effi

cien

t

Class1Class2Class3Class2a

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.01 0.1 1 10

T[s]

Co

effi

cien

t

Class1Class2Class3 Before

0.35

0.37

0.39

0.41

0.43

0.45

0.47

0.01 0.1 1 10T[s]

To

tal

sig

ma

SP96EC8ROVUR-MIUR-MI5No classsoil/rock

0.20

0.22

0.24

0.26

0.28

0.30

0.32

0.34

0.36

0.01 0.1 1 10T[s]

inte

rsta

tio

n s

igm

a

SP96EC8ROVUR-MIUR-MI5No classsoil/rock

INGV-DPC S4 riunione Siena 28-29 Aprile 2010 ITACA the Italian strong-motion database Task5 – site...

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Transcript of INGV-DPC S4 riunione Siena 28-29 Aprile 2010 ITACA the Italian strong-motion database Task5 – site...