SIGMA-2 overview

In recent years, attempts have been made to identify and quantify uncertainties in seismic hazard estimations. This was for instance the main objective of the SIGMA project. These studies have highlighted the lack of representative data, of validated models, and the needs for testing of hazard models against observations.

Almost all experts agree that uncertainties have to be taken into account, and some important progresses have been made in this field.

Nevertheless, even if the nature of uncertainties is now well known and differences between epistemic and aleatory uncertainties clearly indentified the reduction of uncertainties remains a challenge. The adequacy between available data and models or methods has to be carefully addressed.


The industrial partners of the project operate facilities, including nuclear facilities, which should be protected against the effects of earthquakes, for safety reasons and for economic reasons.

Seismicity is an unpredictable phenomenon, imperfectly known.

Significant progress has been made in recent years in understanding the phenomena, in the development of methods for determining seismic movement possible or expected at a site, in the acquisition of seismic data and site response data, in the treatment of uncertainties.

A major effort was made to provide data and methods useful in determining the hazard, in addition to a deep understanding of phenomena

Some issues remain to be improved to make the estimation of hazard more robust, to improve the representation of seismic motion, and to have a proper consideration of hazard in nuclear safety.


This site presents the proposed technical program, and the organization that could be set to finance and perform the program.

The 6 Work Packages (WP) are :

  1. faults and tectonics
  2. earthquake parameters
  3. ground motion prediction
  4. Site Response
  5. PSHA
  6. Requirements for engineering