Regional physics-based simulation of ground motion within the Rhȏne Valley, France, during the MW 4.9 2019 Le Teil earthquake

Abstract

In this paper, a comprehensive validation exercise of 3D physics-based numerical simulations (PBS) of seismic wave propagation is presented for a low-to-moderate seismicity area in the south east of France, within the Rhône River Valley, that hosts several operating nuclear installations. This area was hit on Nov 11, 2019, by an unusually damaging Mw 4.9 earthquake (Le Teil event). The numerical code SPEED ( http://speed.mox.polimi.it/ ), developed at Politecnico di Milano, Italy, was used to validate the simulations against the available recordings. When comparing simulations with records, a good to excellent agreement was found up to 8-10 Hz, showing that, even without a very detailed 3D numerical model of the medium, the PBS may provide realistic broadband predictions of earthquake ground motion. This also demonstrates that PBS, if suitably calibrated and validated, may be either an alternative or a useful complement to empirical ground motion models. Referring to the seismic risk evaluation of strategic and critical structures, infrastructures and industrial plants, such as nuclear power plants, the failure of which during an earthquake may endanger safety of population and cause environmental disasters, the 3D PBS may throw light on region-and site-specific features of ground shaking, especially in near-source conditions, that are typically poorly constrained in empirical models.

Engineering validation of BB-SPEEDset, a data set of near-source physics-based simulated accelerograms

“…near-source regions and very soft basin sites), without making use of either linear scaling or of spectral matching, which may alter significantly the physical nature of the input motions and, consequently, the meaningfulness of results; Provide ensembles of input motions for NLTHA of critical structures (e.g. Nuclear Power Plants, see Abell et al, 2018;Castro-Cruz et al, 2021;Smerzini et al, 2023), containing those source-, region-, and site-specific features that may not be included in suite of motions extracted from global ground motion data sets; Better constrain the input definition particularly for: (1) the calibration of both empirical and analytical fragility curves (Rosti et al, 2023;Zhang et al, 2023); (2) spatially variable multi-support excitations for the seismic analysis of infrastructure systems (Smerzini, 2018;Taslimi and Petrone, 2023); (3) specific near-field studies requiring sets of pulse-like ground motion series; (4) region-specific ground motions in large urban areas, including their spatial correlation (e.g. Chen and Baker, 2019;Infantino et al, 2021b;Schiappapietra and Smerzini, 2021).…”

“…We finally note that, similar to data sets of recorded accelerograms, the BB-SPEEDset is continuously updated as results of new PBS are made available to cover other geological and tectonic frameworks, such as low-magnitude shallow earthquakes from either induced seismicity (Paolucci et al, 2021b) or low seismicity regions (Smerzini et al, 2023), or from specific near-source conditions, such as pulse-like motions, fling step, and hanging wall effects.…”

“…Provide ensembles of input motions for NLTHA of critical structures (e.g. Nuclear Power Plants, see Abell et al, 2018; Castro-Cruz et al, 2021; Smerzini et al, 2023), containing those source-, region-, and site-specific features that may not be included in suite of motions extracted from global ground motion data sets;…”

2D FEM Numerical Prediction of Local Seismic Effects at San Salvador Municipality (El Salvador) Induced by 2001 Earthquakes

“…Numerical prediction of local seismic effects in urban areas is performed worldwide through 1D, 2D, and 3D simulations based on methods such as Finite Element (FE) [1][2][3][4][5][6], Finite Difference (FD) [7][8][9][10] and Spectral Element (SE) [11][12][13] and the references herein. This approach aims at modelling the complex geo-morphological and litho-technical subsoil characters to predict the effect at the surface of the seismic wave propagation, in terms of spectral acceleration, velocity and displacements, and amplification factors and functions [14] and to evaluate the influence of these effects on damage over large areas [15].…”

“…Among the research objectives are seismic hazard assessment and the evaluation of the co-seismic effects at urban sites to increase the resilience of people living in the city centres affected by large earthquakes. This is the case of the large municipality of San Salvador, also known as MASS (Metropolitan Area of San Salvador), which has been hit and damaged by the seismic events on 13 January (M w 7.6) and 13 February 2001 (M w 6.6).…”