Strong Motion Session Announcement

Dear Colleagues,

This message is to call your attention to a special Topical Session that may interest you at the upcoming 2007 IUGG Meeting in Perugia, ITALY (2-13 July 2007). The Session is on state-of-the-art strong motion estimation techniques as well as understanding associated ground motion estimation uncertainties:

Session SS004: "Earthquake Hazard, Risk, and Strong Ground Motion -
Estimation of strong ground motion"

The scope of the session is outlined below, and more details are available at the Meeting website http://www.iugg2007perugia.it/

Thanks for considering submitting an Abstract for this session. Please note that the Abstract deadline is January 31st, 2007. We look forward to meeting with you in Perugia.

Please feel free to contact us for any information.

Conveners,

John Douglas, j.douglas@brgm.fr
Peter Suhadolc, suhadolc@dst.units.it
David Wald, wald@usgs.gov

SCOPE OF THE SESSION:

The accurate estimation of the characteristics of the shaking that occurs during damaging earthquakes is vital for efficient risk mitigation in terms of land-use planning and the engineering design of structures to adequately withstand these motions. At present there are numerous methods for estimating these characteristics ranging from empirically-based methods using data recorded during previous earthquakes (commonly referred to as attenuation relations), through kinematic simulation methods of various complexity to fully dynamic models. In addition, there are a number of hybrid methods that seek to combine benefits of different approaches. These methods all have their own advantages and limitations that are not often discussed by their proponents. Contributions to this session are sought that discuss these different methods of ground-motion prediction, in particular, with respect to their associated uncertainties and also the advantages and disadvantages of different methods. What is the most appropriate method to use for varying quality and quantity of input data and for different seismotectonic environments? How can the best use be made of the available data? How can the uncertainties associated with a given method be properly accounted for?

Ground-motion estimation in regions of the world where strong-motion recording history is short (most regions of the world outside California and Japan) and/or seismic activity moderate poses particular problems since there is limited observational data to allow robust empirical prediction or to constrain free parameters in simulations. Reliable ground-motion estimates are, however, required for these parts of the world in order to correctly estimate the earthquake risk and often, for high importance facilities such as nuclear power stations, for long return periods. Contributions that address the issue of how to provide reliable ground-motion estimates in regions with limited observational data are invited.

The associated uncertainties within ground-motion prediction remain high despite many decades of research and many sophisticated techniques. The unchanging level of aleatoric uncertainties within empirical ground-motion estimation equations over the past thirty years are an obvious example of this. However, estimates from simulation methods are similarly affected by large (and often unknown) uncertainties. These large uncertainties oblige earthquake engineers to design structures with large factors of safety that may not be required. Papers that suggest methods to reduce the uncertainties associated with ground-motion estimates by, for example, better characterising the earthquake source, travel path or recording site are requested.