Are Seismological Signals Recorded at Free-field? Recommendations for Taking Better Account of Installation Conditions When Using Existing Databases and for Installing New Stations
Description:
Accurate and reliable ground motion records are essential for accurate assessment of seismicity and seismic hazard. Current ground motion databases used to develop ground motion models (GMM) rarely provide information on sensor installation conditions, and are often regarded as free-field measurements. However, the various seismological networks use a wide variety of sensor installation methods. These different installation conditions have a significant impact on the recorded motion (amplification or deamplification, the amount of which depends on frequency). We will show, on the basis of real cases, how these installation conditions impact recorded signals, and how these differ from signals recorded in “true free field” conditions. These examples will be taken from experiments carried out in Greece. We'll look at the effects of sensor installation depth (e.g. sensors located in post-holes, manholes or tunnels), the effects of soil-structure interaction (e.g. sensors located in the foundation slab or basement of buildings), the effects of seismic slabs or pillars sometimes used to couple sensors to the ground, and the effects of short-wavelength topography.
Beyond this inventory of disturbing phenomena, we will present the international effort initiated to 1/ better document the installation conditions of existing stations in the metadata of seismic motion databases, so that users can more effectively take into account (and if necessary correct) these installation effects, and 2/ draw up a best practice guide for the installation of seismological stations (in the context of deploying new stations or updating existing ones) to minimize the effects of external disturbances. This work is being carried out in coordination with the “Site Characterization” working group of the Consortium of Organizations for Strong Motion Observation Systems (COSMOS).
Session: Station Installations and Site Conditions, a Quest for Improved Strong Motion Database - II
Type: Oral
Date: 4/16/2025
Presentation Time: 05:00 PM (local time)
Presenting Author: Fabrice
Student Presenter: No
Invited Presentation:
Poster Number:
Authors
Pauline Rischette pauline.rischette@cea.fr French Alternative Energies and Atomic Energy Commission, University of Grenoble Alpes, Institute of Earth Sciences |
Fabrice Hollender Presenting Author Corresponding Author fabrice.hollender@cea.fr French Alternative Energies and Atomic Energy Commission, University of Grenoble Alpes, Institute of Earth Sciences |
Nikolaos TheodoulIdis ntheo@itsak.gr Institute of Engineering Seismology and Earthquake Engineerits, Earthquake Planning and Protection Organization |
Zafeiria Roumelioti zroumelioti@upatras.gr University of Patras |
Vincent Perron vincent.perron@cea.fr French Alternative Energies and Atomic Energy Commission, University of Grenoble Alpes, Institute of Earth Sciences |
Paola Traversa paola.traversa@edf.fr Electricity of France, TEGG |
Margaux Buscetti margaux.buscetti@cea.fr French Alternative Energies and Atomic Energy Commission, University of Grenoble Alpes, Institute of Earth Sciences |
Isabelle Douste-Bacque isabelle.douste-bacque@univ-grenoble-alpes.fr Grenoble Alpes University, Institute of Earth Sciences |
Agisilaos Konidaris konidaris@ionio.gr Ionian University |
Are Seismological Signals Recorded at Free-field? Recommendations for Taking Better Account of Installation Conditions When Using Existing Databases and for Installing New Stations
Session
Station Installations and Site Conditions, a Quest for Improved Strong Motion Database