The key questions we have in mind are: What is the best strategy to fill in the gap in knowledge and know-how in Europe when considering faults in seismic hazard assessments? Are field geologists providing the relevant information for seismic hazard assessment? Are seismic hazard analysts interpreting field data appropriately? Is the full range of uncertainties associated with the characterisation of faults correctly understood and propagated in the computations? How can fault-modellers contribute to a better representation of the long-term behaviour of fault-networks in seismic hazard studies?
An informal working group called Fault2SHA was born to try answering these questions. Fault2SHA group is open to all the interested researchers; sharing ideas, methodologies and case studies are the main topics.
The group met in Paris in November 2014, partly financed by the Institute of Radioprotection and Nuclear Safety. It motivated some exchanges between field geologists, fault modellers and seismic hazard practitioners, but what emerged is that field geologists are not necessarily familiar with probabilistic seismic hazard assessment methods and needs, and that practitioners do not necessarily propagate the "full" uncertainty associated with the fault characterisation. The group met again in 2015 in Chieti (Italy), to share concepts and ideas through specific exercises on a test case study.
In April 2016 at EGU in Wien, a session and a splinter meeting were dedicated to share solutions and problems of seismic source characterisations in seismic hazard assessment, and to debate on the peculiarities of using faults in SHA in Europe.
At the ESC 35rd General Assembly, we hope the European scientific community will contribute to the discussion, providing some answers to the previous questions, thus joining and promoting the Fault2SHA activities.
The session is open to contributions that aim to describe and compare:
• Fault-based SHA models;
• SHA-fault practitioners’ experiences in implementing and complementing by different disciplines (e.g. paleo-speleo-archeo-historical-instrumental seismology; geodesy; etc.);
• Faults uncertainties treatment (e.g. fault characterisation in the field, implementation in SHA codes and resulting variability in expected ground-motion);
• Testing approaches to ensure that the wealth of data available today is used following state-of-the-art methods, rigorous uncertainty handling, and appropriate input model parameterisation.