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Room: Key Ballroom 11

Date: 4/16/2025

Session Time: 2:00 PM to 3:15 PM (local time)

Station Installations and Site Conditions, a Quest for Improved Strong Motion Database

This session emphasizes the practical challenges related to how seismic data is recorded and to the factors that introduce uncertainties in ground motion databases. Ground Motion Models (GMMs) used in seismic hazard assessment (SHA) often rely on proxies to model site effects. These proxies are often estimated indirectly because of the lack of site characterization of the seismic station used to develop the strong-motion database. Either  directly or indirectly assessed, the use of proxies introduce uncertainty in GMMs predictions. Moreover, in empirical GMMs it is often assumed that the earthquakes are recorded at the free surface of the earth, that sensor installation conditions and seasonal effects can be neglected, and that all instruments provide recordings with reliable amplitudes. In practice, many seismic stations are located at depth (e.g., in boreholes or in tunnels) or in an urban environment, errors in the metadata can be found, and detailed site characterization and site-effect assessment are performed only on a limited subset of stations.

With this background, this session welcomes contributions highlighting any effects (from station installation conditions to complex site-effects) that could affect the recorded ground motion, with consequent implications for GMMs, especially at high frequencies. Topics of interest include data processing and data quality control, soil-instrument coupling, soil-structure interactions, depth effects (down-going waves), seasonal variations, topography effects, site effects, site characterization, regional and local attenuation, and small-scale heterogeneity and scattering. Studies demonstrating the value of site instrumentation and characterization in improving site-specific SHA are also encouraged. Studies focusing on improving our current practices in earthquake database implementation or on the enhanced understanding of the high-frequency content of seismic records are particularly welcome.

Conveners 

Fabrice Hollender, CEA Cadarache (fabrice.hollender@cea.fr)
Vincent Perron, CEA Cadarache (vincent.perron@cea.fr)
Zafeiria Roumelioti, Department of Geology, University of Patras (zroumelioti@upatras.gr)
Paola Traversa, Electricity of France (paola.traversa@edf.fr)

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