1. British Seismology Meeting 5th – 7th April 2017, Reading, UK
Probabilistic seismic hazard model outcomes from the SIGMA research programme
Gloria SENFAUTE
Seismologist, PhD
Elecrticité de France EDF
Aix en Provence, France
Vnn
British Seismology Meeting
5th – 7th April 2017, Reading, UK
British Seismology Meeting 5th - 7th April, 2017

2. What is SIGMA ?
A Research & Development programme (2011 – 2016) to improve knowledge, methods and tools to better quantify and reduce uncertainties in seismic hazard assessment
4 Sponsors :
35 International organisations : universities, research centres, engineering consulting...
14 PhD students,
45 publications in peer reviewed international journals
Project leader !
British Seismology Meeting 5th - 7th April, 2017

3. OBJECTIVE
To present the progress of SIGMA to elaborate a Probabilistic Seismic Hazard Model (PSHA) for regions with low to moderate seismicity
Typical product
of a PSHA :
Annual rate with which various levels of Ground Motion are expected to be exceeded at the site of interest
British Seismology Meeting 5th - 7th April, 2017

4. THE ELEMENTS OF PSHA SIGMA progress: Magnitude Frequency distributions
Geometry of sources
Seismic Catalogue for the French territory
Magnitude Frequency distributions
Max Magnitude
Seismic ground motion
data base and new
GMPEs
SIGMA progress:
British Seismology Meeting 5th - 7th April, 2017

5. SEISMIC CATALOGUE Researches carried out in 3 periods :
Before SIGMA any homogenous catalogue in moment magnitude in France.
Researches carried out in 3 periods :
Instrumental (1962– 2009);
Early-instrum (1905 – 1972);
Historical (463 – before 1905)
Homogenous in Mw
Uncertainties for the estimate parameters
Cara et al 2015 BSG; Deunieul et al 2015 BSSA
Baumant et al, Traversa et al, Manchuel et al (submitted in BEE, 2017)
British Seismology Meeting 5th - 7th April, 2017

6. Magnitude-Frequency distribution
MFDs from synthetic catalogues sampling the Mw uncertainties in the original one
200
Synthetic
catalogues
for each zone
The uncertainties in the G-R parameters is quantified by propagating the uncertainties in terms of earthquake magnitude
British Seismology Meeting 5th - 7th April, 2017

7. MAXIMAL MAGNITUDE FOR PSHA CALCULATIONS
Impact of Mmax on the final PSHA result
Mmax SHARE model
Mmax Bayesian Approach
Mmax observed + increment + scaling
Annual rate of excedance
Bayesian approach EPRI (1994) :
European Prior Mmax distribution SCR 5
5.5 6
6.5 7
7.5 8
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9 1
MMAX
PDF
PRIOR Mmax distribution
European ACTIVE
European STABLE
EPRI(1994) non-extended crust
EPRI(1994) extended crust
Ameri et al 2016, AFPS
British Seismology Meeting 5th - 7th April, 2017

8. 9 new GMPEs : GROUND-MOTION ATTENUATION MODELS * 1. 2. 3. 4. 5.
Akkar et al.
Bindi et al.
Bora et al.
Hermkes et al.
Derras et al.
Parametric models
Data-driven models
Empirical FAS, duration + RVT
Douglas et al
Bull Erth Eng
2014 1. 2. 3. 4. 5. *
Akkar et al 2013, BEE
6. Stochastic GMPE for low seismicity areas - Drouet & Cotton 2015, BSSA
7. GMPE for a new intensity measure ASA40 - Koufoudi et al 2014, De Biasio et al 2015
8. GMPE for Europe + weak motions – Ameri et al, submitted BEE
9. Regional GMPE for Po Plain area – Lanzano et al, BSSA
*Research using the SIGMA data but not directly funded by SIGMA
British Seismology Meeting 5th - 7th April, 2017

9. PSHA Calculations:19 sites
British Seismology Meeting 5th - 7th April, 2017

10. RESULTS RP 475y Comparing : SIGMA PSHA model (2016) &
MEED
SIGMA
MEED
RESULTS
Comparing :
SIGMA PSHA model (2016) &
MEED model (2002)
20 sites
X : median SIGMA model
: means SIGMA model
: means MEED model
X : median MEED model
Bars 16th – 84th fractiles
Martin et al 2017 submitted in BEE
British Seismology Meeting 5th - 7th April, 2017
PGA (g)
PSA 1s(g)

11. RESULTS RP 475y Comparing SIGMA PSHA model and SHARE European model
20 sites
X : medians SIGMA model
: means SIGMA model
: medians SHARE model
X : medians SHARE model
Bars 16th – 84th fractiles
Martin et al 2017 submitted in BEE
British Seismology Meeting 5th - 7th April, 2017
PGA (g)
PSA 1s (g)

12. Conclusions
SIGMA provided a reference for the PSHA practices and set new standards for future studies. The majors improvements are:
The use of a homogenous earthquake catalogue in Mw with associated uncertainties.
The assessment of the maximum earthquake magnitude by applying a Bayesian approach that avoid the excessive use expert judgment.
The use of a new set of GMPEs developed for the Pan-European region.
The logic tree is improved by considering recent progress in PSHA practices (faults models, smoothed seismicity models)
SIGMA PSHA model was compared with national and international models providing overall lower accelerations with respect the others models.
British Seismology Meeting 5th - 7th April, 2017

13. Thanks for your attention
PERSPECTIVES:
Starting in 2017
Thanks for your attention
British Seismology Meeting 5th - 7th April, 2017