Content on this page requires a newer version of Adobe Flash Player.

Get Adobe Flash player

Scientific Objectives

The objective of the SIGMA projects is to improve knowledge on data, methods and tools to better
Quantify Uncertainties
in seismic hazard estimates. The programme is organised in five main Work Packages:

WP1 A better knowledge of seismic sources

The two main goals are to produce a catalogue of earthquakes that covers both the historical and instrumental periods, and to improve knowledge of faults and geological structures that are potentially active.

WP2 To develop methods of ground-motion prediction

The goal is to develop methodologies and analysis tools for predicting seismic ground motion that are adapted to the French context and nearby countries, and that uses a realistic representation of physical and epistemic uncertainties.

WP3 Improve local site conditions characterization

The goal is to develop methods and tools to evaluate sites potentially subjected to local site effects, and that are appropriate to be used in the seismic hazard calculation methods.

WP4 Improve Seismic Hazard Models

The intention is to better identify and quantify uncertainties with the goal to reduce them, particularly the epistemic uncertainties. It is proposed to validate and introduce methods that are existing or are in the process of being developed, and to explore new directions, for testing probabilistic hazard curves against observations.

WP5 Improve characterization and exploitation of seismic ground motion

The studies in this work package are to ensure that results of the overall project fulfil engineers’ and designers’ needs for the design and operations of various facilities types. Its goal is to produce methods and tools for the development of the required engineering parameter(s) of the seismic ground motion, for several return periods, and various levels of risk, adapted to the facilities.


WP 1

Improve the knowledge of seismic source faults

Technical tasks:

1. Fault

  • Development of database structure for faults and geological structures

  • Description of the faults and geological structures: South Eastern France and Po Plain, Italy

  • Analysis of one mega structure (Belledonne fault), France

  • Study of earthquake recurrence models, Italy


2. Historical Seismicity

  • Add information to SEISFRANCE

  • Determine ISOSEISMAL curves of the XXth century, France

  • Perform statistical analysis of macroseismic data, France

3. Instrumental Seismicity
  • Improve characterization of XXth century earthquakes, France

  • Improve the Mw magnitudes of all instrumental earthquakes since 1962, France

  • Creation of an earthquake final catalogue, France



WP 2

Improve seismic ground motion prediction

Technical tasks:

1. European databank of seismic ground motion
  • Construction of a homogeneous, high quality, complete databank of seismic motion for Europe. Quantification of uncertainties associated to metaparameters. Improving the characterization of some key sites.

2. Ground-motion model for France and nearby regions
  • Development/adjustment of ground-motion models adapted to the French, Northern Italy and nearby regions context. Aggregation of existing ground motion prediction equations.

3. Data-driven selection, testing and ranking of GMPEs
  • Data-driven selection, testing and ranking of GMPEs for France, Northern Italy and nearby regions.

4. Ground motion simulation
  • Site-specific ground motion simulation techniques (e.g. Spectral Element Method, Empirical Green Functions, Stochastic Simulations). Comparison of simulations vs empirical predictions.


5. Ground motion variability
  • Methods to improve the understanding of ground motion variability.  Removing the ergodic assumption.  Improving the evaluation of model and parametric uncertainties in ground-motions simulations.

Work Package 2

WP 3

Improve the local site effects

Technical tasks:

1. Definition of incident seismici waves
  • Definition of incident waves using accelerometric and macroseismic data.


2. Characterization of sites
  • Evaluate uncertainties in non-invasive characterization methods

  • Evaluation of influence of non linear effects.

  • Identify the important site parameters, sensibility study


3. Methodology to account for site effects
  • Evaluate numerical simulation tools, impact of geology uncertainty on simulation results

  • Definition and selection of the site/reference data

  • Apply methods to a representative number of real and/or virtual sites

  • Produce an operation methodology for site effects identification


These research activities are shared with the CASHIMA Program


Work Package 3

WP 4

Improve seismic hazard models

Technical tasks:

1. Perform a probabilistic study for South East France and Northern Italy to produce a preliminary hazard map
  • Use the latest advances in the scientific field to produce an up-to-date hazard map as a starting point for testing the benefits of SIGMA results


2. Development of methods for testing probabilistic seismic hazard estimates against observations

  • To develop new testing methods for comparing the ground-motion distribution with observations. The methods will be implemented and tested in order to clearly understand their potential as well as their limits and precision.


3. Estimation of seismic risks using structural fragility functions and macroseismic intensity data
  • To develop a methodological approach for comparing two methods of seismic risk assessment and finding an original way to qualify the seismic hazard model in low to moderate seismicity regions.



WP 5

Improve characterization and exploitation of seismic ground motion

Technical tasks:

1. Identification of relevant seismic effect parameters
  • Identify seismic design parameters and thresholds appropriate for vulnerability assessment


2. Scenario selection
  • Develop the method of conditional spectra on the south east of France, to use a smaller number of unique time histories (50-100) while still preserving the hazard over the range of frequencies and range of hazard levels that are important for the structure and the systems.

  • Develop optimization methods to reduce the number of needed time histories.

  • Evaluate the conservatism in current practice by comparing the computed risk or system response (for deterministic evaluations) using the conditional spectra method and using the current UHS method.



Cashima Program


The Cashima program (Cadarache Seismic Hazard Integrated Multidisciplinary Assessment) was launched in 2005. It is jointly supported by the French Atomic Energy and Alternative Energies Commission (CEA, and the Institut Laue Langevin (ILL,


This program aims to produce a common knowledge base, shared by the scientific community, on the site effects phenomena (in general) and on the Provence seismotectonic features.


The Cashima program also animates the "EuroseisTest Verification and Validation Project" which involves more than ten international teams on the issue of performance evaluation of the seismic motion simulation tools.

The research activities of the Cashima program are shared with the SIGMA program since 2011.


Return to top