CSNI Workshop

Workshop on seismic input motions, incorporating recent geological studies

Tsukuba, Japan 15-17 November 2004

Hosted by the Japanese National Research Institute for Earth Science and Disaster Prevention (NIED)

Workshop background

This workshop is planned to review the state of the art in defining realistic seismic input for the design and reevaluation of nuclear facilities. Recent advances in source characterisation of fault zones using data from deep geological investigations and their possible contribution to improvement of seismic input definition will be reviewed.

Scope, content and outline of the workshop

Recently, geologists have been actively studying deep geology of active faults including deep bore holes drilled across these zones. Seismologists have been developing techniques to estimate future ground motions. However these techniques include various uncertainties (e.g., due to the lack of a priori knowledge of fault zone asperities). Surveys of the structure of capable faults and soil strata, by deepbore hole studies, on-site measurements and other advanced methodologies may reduce these uncertainties. Engineers will improve the seismic safety of NPPs through this more physical approach in addition to previous experience-based methods.

In 1999, a workshop held at Brookhaven National Laboratories by the USNRC addressed the engineering characterisation of seismic input and emphasised the potential benefit of the collaboration between earth scientists and seismic engineers. It was followed in 2002 by a workshop held in Istanbul by TAEK where relations between seismological data and seismic engineering analyses were examined. This workshop is a continuation of these two workshops that have facilitated multi-disciplinary collaboration, and have proved to be valuable to seismic engineers in the nuclear field. Papers should address the objectives and contribute to the expected products of the workshop. Several sessions with ample time for discussion will address the following topics:

Deep bore holes and asperities;
Hidden faults;
Simulation of source paths and site effects;
Seismic measurements (arrays, deep hole measurements…);
Seismic variables in relation to damage (acceleration, velocity, displacement…spectral quantities);
Uncertainties and methodologies for their reduction;
Regulatory implicationsI

A final session will summarise the discussions and develop conclusions and recommendations for possible further actions by the CSNI. All the participants are expected to take part in the discussion and in the formulation of conclusions in the final session.