SYNTHESIS 0.1: what future?

Napoli 27 Marzo 2014

Pacor F., D’Amico M., Luzi L., Puglia R., Russo E., Gallovic F.

GOALS

• To archive and to distribute through the WEB synthetic waveforms

• To promote the use of synthetic seismograms as integration to

the observed ground motion

• To furnish an usable tool for – Scientific purpose

» Analysis of Ground Motion variability » Integration Ground Motion Prediction Equation

– Seismic risk mitigation » Damage scenarios » Microzonation

– Engineering application » Seismic input definition for the structural design

WHAT IS SYNTHESIS? …. a synthetic waveforms repository

http://synthesis.mi.ingv.it/

Synthetic database ensures a) Trasparency b) Repeatibility c) Data availability

Progetto Reluis (20010-2012), Progetto INGV-DPC S3 (2005 – 2007)

WHAT IS SYNTHESIS? ….a relational database management system (Mysql®)

SCENARIOS

SYNTHETIC WAVEFORMS

STATIONS

Using the structure of ITACA!

HOW IT WORKS? ….. the database structure

http://dyna.mi.ingv.it/synthesis/

References

Scenarios

Synthetics Waveforms

Stations

13

11

10

EXPLORING SYNTHESIS scenarios search

Search Criteria

Link to scenario details

EXPLORING SYNTHESIS scenarios details

Waveform detail Ground Motion Parameters Link to Stations

Link to waveforms

EXPLORING SYNTHESIS station search

EXPLORING SINTESIS synthetics waveforms search

EXPLORING SINTESIS synthetics waveforms search

EXPLORING SYNTHESIS scenario gallery

DATABASE POPULATION

IRPINIA FAULT Some numbers 3 simulation techniques: HIC, EXSIM, DSM We include 54 scenarios for each technique 6 nucleation points x 3 rupture velocities x 3slip

distributions 144 virtual observers

24084 waveforms!!!!!

NEW STRATEGY

• Selection of synthetic waveforms based on specific features of the ground motion parameters

Freq

(a)

mean

a

maximum

a

compatible with a predictive equation

COSENZAEXAMPLE

Length

(km)

Width (km) Average displacement

(m)

M7 37 26 1.4

M6 13 9 0.4

M5 4 2.7 0.13

• Cosenza case study:

Three seismic sources were simulated, able to generate events of magnitude M equal to 5.0, 6.0, e 7.0

2 2.4 2.8 3.20

10

20

30

40

50

M12 2.4 2.8 3.2

0

10

20

30

40

50

M3

2 2.4 2.8 3.20

0.5

1

1.5

2

2.5

G2

2 2.4 2.8 3.20

10

20

30

40

50

M5

M #Nucleation

Point

#rupture

velocity

#k #stress

drop

#modeled

fault

#simulation

7.0 27 3 3 1 1 243

6.0 9 3 3 1 5 405

5.0 1 1 3 4 13 156

1.2 1.6 2 2.4 2.80

4

8

12

16

20

M11.2 1.6 2 2.4 2.8

0

10

20

30

40

M2

1.2 1.6 2 2.4 2.80

0.4

0.8

1.2

1.6

G2

1.2 1.6 2 2.4 2.80

10

20

30

40

M5

M 7 R 0km M 6 R 4km 1.6 2 2.4 2.8 3.2

0

10

20

30

40

M11.6 2 2.4 2.8 3.2

0

10

20

30

40

50

M3

1.6 2 2.4 2.8 3.20

0.4

0.8

1.2

1.6

G2

1.6 2 2.4 2.8 3.20

20

40

60

80

M5

M 6 R 0km

50° percentile PGA

ID_source 7030 (M7.0)

Massimo Valore PSA 1 Hz

ID_source 6030 (M6.0)

Cosenza scenarios

1 simulation technique: DSM

We simulate 648 scenarios (M 7 and M6), but we include

55 waveforms!!!!!

Proposal

For each scenarios-park

• To establish selection criteria to include synthetic seismograms based on the statistical distribution of the ground motion parameters (i.e. mean, median, percentiles, etc.); Max 5 – 10 synthetics for each observer;

• To populate the database with strong motion parameters for all scenarios

• To reduce the number of virtual observers

• To provide all synthetic dataset on demand

Generator of slip rates

Gallovič & Brokešová, 2007

Source model

Basic idea

• The earthquake source is coherent at low frequencies (short

wavelengths), while incoherent at high frequencies (long wavelengths)

Such a coherent model would overpredict the high-frequency directivity effect!

Subsource distribution

and slip

Moment rate a source spectrum

L0 = 0.2L

Examples of slip rates

L0 = 0.2L

Seismograms and spectra

L0 = 0.2L

Seismograms and spectra

L0 = 0.05L

Drawbacks of the present version

• Constant rupture velocity over the fault

• Does not estimate/correct stress drop

• Rupture on small-scale subsources starts from the middle (not from a random point)

References

• Bernard, P., Herrero, A., 1994. Slip heterogeneity, body-wave spectra, and directivity of earthquake ruptures. Ann. Geofis. XXXVII, 1679–1690.

• Bernard, P., Herrero, A., Berge, C., 1996. Modeling directivity of heterogeneous earthquake ruptures. Bull. Seism. Soc. Am. 86, 1149–1160.

• Gallovič, F., Burjánek, J. (2007). High-frequency Directivity in Strong Ground Motion Modeling Methods, Annals of Geophysics, Vol. 50, N. 2, 203-211.

• Gallovič, F., Brokešová, J. (2007). Hybrid k-squared Source Model for Strong Ground Motion Simulations: Introduction, Phys. Earth Planet. Interiors, 160, 34-50.

• Gallovič, F., Brokešová, J. (2004). On strong ground motion synthesis with k^-2 slip distributions, J. Seismology, 8, 211-224.

• Herrero, A., Bernard, P., 1994. A kinematic self-similar rupture process for earthquakes. Bull. Seism. Soc. Am. 84, 1216–1228.

• Ruiz, J. A., D. Baumont, P. Bernard, and C. Berge-Thierry (2011). Modeling directivity of strong ground motion with a fractal, k-2, kinematic source model, Geophys. J. Int. 186, 226–244.