High Frequency Attenuation of Seismic Waves Due to the Heterogeneous Nature of the Crust : Theoretical Developments and Numerical Investigations
Description:
Predicting the observed attenuation at high frequency remains an open issue of strong ground motion modeling due to its dependence on many factors (such as intrinsic attenuation, crustal heterogeneities, source rupture mechanism and so on). In practice this phenomenon is taken into account via empirical parameter such as so-called kappa.
In this work, we proposed to study the high frequency attenuation using high fidelity earthquake numerical simulation at regional scale and theoretical developments of the elastodynamic equations in order to show the impact of crustal heterogeneities on the traveling wave.
First, the theoretical developments are done taking into account the heterogeneities of the medium considering randomly fluctuating mechanical properties. From the stochastic differential equations, the results obtained gives the transmitted coefficient which can be directly linked to the high frequency attenuation.
Secondly, the numerical simulations lead to study the high frequency attenuation on a broad band (0.1-20Hz) based on the computation of kappa parameter applied to synthetic data generated for different realizations of the mechanical properties. The computation of kappa is done at different locations for different realizations in order to highlight the impact of the random properties on the frequency content.
Finally, an estimation of the kappa value is provided based on synthetic data and compared to the theoretical formula obtained from stochastic differential equations. The high frequency decay obtained numerically is close to the analytic results considering a regional attenuation.
Session: High-frequency Ground Motion Measurements, Assessments and Predictions
Type: Oral
Date: 4/18/2023
Presentation Time: 08:15 AM (local time)
Presenting Author: Martin Colvez
Student Presenter: No
Invited Presentation:
Authors
Martin Colvez Presenting Author Corresponding Author martin.colvez@centralesupelec.fr French Alternative Energies and Atomic Energy Commission, DAM, DIF |
Fernando Lopez-Caballero fernando.lopez-caballero@centralesupelec.fr Laboratoire de Mécanique Paris-Saclay, Université Paris-Saclay, ENS Paris-Saclay, French National Centre for Scientific Research |
Régis Cottereau cottereau@lma.cnrs-mrs.fr Aix-Marseille Université, French National Centre for Scientific Research |
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High Frequency Attenuation of Seismic Waves Due to the Heterogeneous Nature of the Crust : Theoretical Developments and Numerical Investigations
Category
High-frequency Ground Motion Measurements, Assessments and Predictions