Calibration of the input parameters in pilot test areas
D. Galluzzo, F. Bianco, H. Langer, L.Scarfi, G. Tusa & G. Zonno• INGV, Catania, Milano, Napoli, Italy
A. Carvalho• LNEC, Lisboa, Portugal
S. Olafsson, R. Rupakhety & R. Sigbjörnsson • EERC, Selfoss, Iceland
M.Garcia Fernandez, M.J. Jimenez, J. Jenny• CSIC, Madrid, Spain
M. La Rocca, M. Massa and R. Nappi are aknowledged for their contributions• INGV, Napoli, Milano
Task C
Main Goals of Task C: Calibration of earthquake source, path and site parameters/physical quantities by comparison between observed and synthetic waveforms. The application of the finite fault stochastic approach.
Simulation of scenarios for strong and rare earthquakes for which real data may not be available
Task C - D E L I V E R A B L E S
C1.1 Definition of the critical points to calibrate the input parameters of the finite fault stochastic program
C2.1 Estimates of input parameters of EXSIM for the pilot study in test area 1(Mt Etna ML=4.8, Mt Vesuvius MD = 3.6 , Campi Flegrei MD=2.2)
C2.2 Estimates of input parameters of EXSIM for the pilot study in test area 2(Azores Islands Mw=6.0, mainland and offshore Portugal)
C2.3 Estimates of input parameters of EXSIM for the pilot study in test area 3(Spain, ML > 4.5)
C2.4 Estimates of input parameters of EXSIM for the pilot study in test area 4(South Iceland MW=6.5)
C3.1 Computation of synthetic ground shaking at the pilot test sites
C4.1 Computation of synthetic macroseismic fields derived from simulated PGV
C5.1 Enriched dataset using observed and synthetic bedrock Mfs.
•Outline Strategy of work:
Calibration of ground motion parameters: application of a stochastic approach (EXSIM code, Motazedian and Atkinson, 2005)
1 - Definition of critical points to calibrate physical quantities and parameters
2 - Calibration: examples of applications for the investigated areas
3 - Conclusions and Further developments
Definition of Critical Points for Calibration Procedure
The different data set characteristics have induced the participants to fix the criticalities that could be arise in managing different areas:
- the low magnitude data set for some areas;
- the application of stochastic approach for small faults;
- the variation of input parameters relative to the wide hypocentral distance range and focal depth of earthquakes;
- the uncertainties associated to some input parameters (stress drop for low magnitude earthquakes and time duration);
- Ground Motion Parmeters to be evaluated: PGA (PGV for small-to-moderate earthquakes), Response Spectra (5%), Housner/Arias Intensity...
• Calibration of input parameters
…the most important parameters: Source: Magnitude, Fault dimensions, Stress Drop,
Subfault divisions
Path: Q(f,R) attenuation parameter
Site: High frequency decay “k” parameter, Empirical ”Site Effect” function
..Others: Time duration
• Source parameter: the Magnitude
Seismic Moment estimation from low frequency flat part of displacement spectrum(Havskov & Ottemoller, 2010)
..a tool for a UNIFORM earthquake size determination …
From Catalogue ML=5.3, from Low Frequency Disp. Spectra Mw=5.1 +/-0.2 2000-06-21 00:55:13 South Iceland EQ
Mw = 5.1
2007-08-01 23:38:16 Mt. Etna EQ
Catalogue ML = 3.2 MD = 3.3 ---- Low Freq. Disp. Spectra Mw = 3.3 +/- 0.2
Mw = 3.3
Mw = 2.5
2012-09-07 07:34 Campi Flegrei EQ
Catalogue MD= 1.7 -- -- LFDS Mw = 2.5 +/- 0.2
•MD [-0.3, 2.2], Depth [0.5, 3.0] km b.s.l., •30 seismic events in the period 2000 - 2012
•Campi Flegrei (Southern Italy, Area 1)
• Epicenters of selected earthquakes (red stars) • Seismic stations (blu triangles)
•..An example of VT earthquake..Volcano-Tectonic Seismic Event occurred on 07-09-2012; MD=1.7
•Geostructural Map of Campi Flegrei (Di Vito et al., 1999)
Fault Geometrical Parameter Strike = 300° , Dip = 80°
Magnitude Mw=2.7
Fault Dimension 0.2 x 0.2 km2
Depth of the fault 2.8 km b.s.l.
Stress Drop 7 bar
Average S-Wave velocity 2.0 km/s
Density 2.5 g/cm3
Attenuation Q parameter Q=27 f 0.6
Geometrical Spreading 1/R
Volcano-Tectonic Seismic Event occurred on 07-09-2012 MD=1.7 --- MW=2.5 +/- 0.2
Calibration Results: Sensitivity to Stress Drop
Sim. 1 bar
Sim. 7 bar
Sim. 15 bar
Obs.E-W
Obs. N-S
Calibration Results: Sensitivity to Stress Drop
Sim. 1 bar
Sim. 7 bar
Sim. 15 bar
Obs.E-W
Obs. N-S
•Stochastic Simulation vs Empirical Results• for VT earthquake occurred on 07-09-2012, 07:34
• [km]
Mt. Vesuvius (Southern Italy, Area 1)•MD [1.5, 3.6], Depth =[0.0, 4.0] km b.s.l., •50 seismic events in the period 1999 - 2012
Fault Geometrical Parameter Strike = 300° , Dip = 80°Magnitude Mw=2.4Fault Dimension 0.2 x 0.2 km2
Depth of the fault 1.7 km b.s.l.Stress Drop 12 barAverage S-Wave velocity 1.7 km/sDensity 2.5 g/cm3
Attenuation Q parameter Q=30 f 0.7
Geometrical Spreading 1/R
2001-04-11 Mt. Vesuvius EQ MD=2.8
Results of Calibration : Sensitivity to Stress Drop
Sim. 1 bar
Sim. 5 bar
Sim. 12 bar
Sim. 20 bar
Obs.E-W
Obs. N-S
Sensitivity to Q and high freq k values
Q=10 f 0.5
Q=30 f 0.7
Q=50 f 0.8
k=0.015
k=0.04
k=0.06
•Mt. Etna (Southern Italy, Area 1)
Epicentres of selected earthquakes and seismic stations of the RSPSO (triangles) for the Etnean zone.
•ML [3.0, 4.8], Depth =[5.0, 30.0] km b.s.l., • more than 120 seismic events in the period 2006 - 2011
Empirical and synthetic ground motion prediction for a superficial ML=3.3 earthquake.
Empirical and synthetic ground motion prediction for a deeper (z= 10 km) ML=4 earthquake.
Results of Calibration procedure: synthetic vs predicted PGA
Azores Island, Mainland and Offshore of Portugal (Area 2)
•ML [3, 6], Depth =[5.0, 30.0] km b.s.l., • 47 seismic events in the period 1969 - 2006
Strong-motion network stations (yellow triangles) in Central Group Azores Archipelago.
Left:Example of k estimations from the amplitude Fourier spectra of acceleration. Right: Example of a displacement-amplitude spectra of S-waves and lines of ω2 model
K parameter estimation
•Southern Spain (Area 3)
Earthquakes 1999-2012 (red circles) and strong-motion stations (white triangles) selected for calibration and validation.
•ML [3.3, 5.2], Epicentral dist. < 100 km, • selected well constrained 24 seismic events in the period 1999 - 2012
Sensitivity of spectral amplitudes (FAS, PSA, PSV) to different values of the stress parameter (50, 100 and
200 bar). (a) Site 1, (b) Site 2.
Results of Calibration : ground motion simulations at two sites (55 km NE, and 5 km SW of the epicenter) were done
to evaluate the effect of stress drop parameters
Results of Calibration procedure: synthetic vs observed FAS and PSA
02/03/2008 M3.5 Vega Baja earthquake. Comparison of recorded and EXSIM-simulated horizontal-component spectral amplitudes (FAS and PSA) at stations TOR, GUA and CTG.
•South Iceland (Iceland, Area 4)
20' 20oW 40'
20.0 km
Hella (HE-105)
Selfoss SF-101 SR-112
Hveragerði
KH-103
Búrfell (BF)Ljósafossvirkjun (LF-306)
TB-502
FL-106
TH-104
MN-108
OM-501 OS-501
SO-109
SA-304SV-307
SL-309SM-309
SL-309LaugarvatnThingvallavatn
Eyjafjallajökull
1912-M7.2
1987-M6.02008-M6.3
2000(21/6)-M6.5 2009(17/6)-M6.5
South Iceland map. The faults of the largest earthquakes since 1912 are indicated and the stations in the Icelandic Strong Motion Network are shown triangles.
0 20 40 60 80 100 120 140-30
-20
-10
0
10
20
30
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.2 Burfell-Hydroelectric Power Station e-distanc = 45
0 20 40 60 80 100 120 140-80
-60
-40
-20
0
20
40
60
80
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.3 Flagbjarnarholt e-distanc = 22
0 20 40 60 80 100 120 140-150
-100
-50
0
50
100
150
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.4 Hella e-distanc = 21
0 20 40 60 80 100 120 140-10
-8
-6
-4
-2
0
2
4
6
8
10
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.5 Hrauneyjafoss-Hydroelectric Power Station e-distanc = 76
0 20 40 60 80 100 120 140-80
-60
-40
-20
0
20
40
60
80
100
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.8 Irafoss-Hydroelectric Power Station e-distanc = 20
0 20 40 60 80 100 120 140-80
-60
-40
-20
0
20
40
60
80
100
120
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.10 Ljosafoss-Hydroelectric Power Station e-distanc = 20
0 20 40 60 80 100 120 140-15
-10
-5
0
5
10
15
20
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.14 Reykjavik-Hus Verslunarinnar e-distanc = 61
0 20 40 60 80 100 120 140-150
-100
-50
0
50
100
150
200
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.15 Selfoss-City Hall e-distanc = 15
0 20 40 60 80 100 120 140-800
-600
-400
-200
0
200
400
600
800
TIME (s)
ACCE
LERA
TION
(cm/
s2 )
Station no.23 Thjorsartun e-distanc = 6
Observed (black dashed) and simulated (red solid curve) Mw6.5 seismic event accelerograms for 9 stations of Icelandic Strong Motion Network.
Calibration and Simulations for the South-Iceland was done earthquake on July 21, 2000 (Mw6.5)
10-2
10-1
100
101
0
10
20
30
40
50
60
70
80
PERIOD (s)
PSA
(cm/s2 )
Station no.2 Burfell-Hydroelectric Power Station e-distanc = 45
10-2
10-1
100
101
0
20
40
60
80
100
120
140
160
180
PERIOD (s)
PSA
(cm/s2 )
Station no.3 Flagbjarnarholt e-distanc = 22
10-2
10-1
100
101
0
50
100
150
200
250
300
350
400
PERIOD (s)
PSA
(cm/s2 )
Station no.4 Hella e-distanc = 21
10-2
10-1
100
101
0
5
10
15
20
25
PERIOD (s)
PSA
(cm/s2 )
Station no.5 Hrauneyjafoss-Hydroelectric Power Station e-distanc = 76
10-2
10-1
100
101
0
50
100
150
200
250
PERIOD (s)
PSA
(cm/s2 )
Station no.8 Irafoss-Hydroelectric Power Station e-distanc = 20
10-2
10-1
100
101
0
50
100
150
200
250
300
PERIOD (s)
PSA
(cm/s2 )
Station no.10 Ljosafoss-Hydroelectric Power Station e-distanc = 20
10-2
10-1
100
101
0
10
20
30
40
50
60
70
PERIOD (s)
PSA
(cm/s2 )
Station no.14 Reykjavik-Hus Verslunarinnar e-distanc = 61
10-2
10-1
100
101
0
100
200
300
400
500
600
PERIOD (s)
PSA
(cm/s2 )
Station no.15 Selfoss-City Hall e-distanc = 15
10-2
10-1
100
101
0
500
1000
1500
2000
2500
PERIOD (s)
PSA
(cm/s2 )
Station no.23 Thjorsartun e-distanc = 6
Acceleration response spectra, with 5% damping, for 9 stations of Icelandic Strong Motion Network. A comparison of the average PSA for the simulations (red curve) and PSA of the measured acceleration records for Mw6.5 earthquake.
Stress Drop (bar) [7 – 250] barMagnitude Mw= [2.0 – 6.5]Q=Q0 fb Q0 = [27-100] ; b = [0.5-1.0]k [0.015 – 0.070]Site Effect Soil Classification, H/V, H/Href
..A synthetic overview…
Conclusions and Further Developments
The Stochastic Aprroach has revealed a good tool to
calibrate source, path and site parameters/physical
quantities; The joint use of the different Data Set has allowed to
define the limits of applicability, the potentiality of
implementation of stochastic procedure and give an
interesting general overview of seismological quantities
referred to different areas; The next step consists on the application of well-
calibrated parameter to genereate large earthquake
scenario.
S I M U L T I O N
S I M U A T I O N
TASK
C
A
L
I B
R
A
T
I
O
N
Thank you!
