The Effect of Short Wavelength Topography on Seismic Recordings: Results of Experiments Conducted on Kefalonia Island in Greece.
Description:
In recent years, seismological networks around the world have been considerably expanded, enabling the creation of databases with a rising number of earthquakes. Nevertheless, the description of the installation conditions of seismological stations are often missing from the networks metadata. In most cases, Ground Motion Models (GMMs) developers assume that these stations are in free-field conditions, i.e. located at the natural surface of the ground without nearby disturbing structures. However, the investigation of seismological networks has revealed the coexistence of many different installation methods, including, for instance the coupling of seismometers, housing of permanent stations, or the installation of some stations at the foot of a scarp. Recent studies have also shown that these installation conditions can have a significant impact on the recorded motion, compared with true free-field measurements. Among these various installation methods, this study takes a particular interest in the effect of topography at short wavelengths. To this end, an experiment has been conducted on Krani Hill on Kefalonia Island in Greece. Ground motion recorded at sensors installed along a profile going from the foot to the top of a cliff of about twenty meters high, are compared among them and with respect to a reference site. Other seismometers have been set up along the cliff, top and bottom, to analyze a potential polarization effect. Recordings of earthquakes and ambient noise have been studied to provide the most possibly comprehensive analysis. The results show a slight amplification of the signal at the top of the cliff and a clear de-amplification at its foot. The clearest effect is a marked polarization of the signal near the scarp.
Session: From Earthquake Recordings to Empirical Ground-Motion Modelling [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Pauline
Student Presenter: Yes
Invited Presentation:
Authors
Pauline Rischette Presenting Author Corresponding Author pauline.rischette@cea.fr French Alternative Energies and Atomic Energy Commission |
Fabrice Hollender fabrice.hollender@cea.fr French Alternative Energies and Atomic Energy Commission |
Nikolaos Theodoulidis ntheo@itsak.gr Institute of Engineering Seismology and Earthquake Engineering |
Zafeira Roumelioti zroumelioti@upatras.gr University of Patras |
Vincent Perron vincent.perron@cea.fr French Alternative Energies and Atomic Energy Commission |
Paola Traversa paola.traversa@edf.fr Electricité de France |
Emeline Maufroy emeline.maufroy@univ-grenoble-alpes.fr Université Grenoble Alpes |
Margaux Buscetti margaux.buscetti@cea.fr French Alternative Energies and Atomic Energy Commission |
Isabelle Douste-Bacqué isabelle.douste-bacque@univ-grenoble-alpes.fr Université Grenoble Alpes |
Agisilaos Konidaris agiskonidaris@gmail.com TEI Ionion Nison, Argostoli, , Greece |
The Effect of Short Wavelength Topography on Seismic Recordings: Results of Experiments Conducted on Kefalonia Island in Greece.
Category
From Earthquake Recordings to Empirical Ground-Motion Modelling