E. D. Mercerat

E. D. Mercerat
CEREMA · Agence de Sophia-Antipolis. DTer. Mediterranee

PhD

About

82
Publications
26,617
Reads
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1,281
Citations
Citations since 2016
45 Research Items
1039 Citations
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2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Introduction
My research activity focuses on the integration of numerical and empirical approaches to study the propagation of seismic waves and their effects on engineering structures and the environment. Being able to test data analysis methodologies on so-called synthetic cases (by numerical modeling) that is controlling the input parameters, represents a remarkable advantage.
Additional affiliations
February 2010 - November 2011
University of Nice Sophia Antipolis
Position
  • PostDoc Position

Publications

Publications (82)
Article
Full-text available
We evaluated a comprehensive numerical experiment of finitefrequency tomography with ray-based ("banana-doughnut") kernels that tested all aspects of this method, starting from the generation of seismograms in a 3D model, the window selection, and the crosscorrelation with seismograms predicted for a background model, to the final regularized inver...
Article
We explore the validity of the linear relation between cross-correlation delay times and velocity model perturbations that is required for linearized finite-frequency tomography. We estimate delay times from a large number of `ground truth' seismograms computed with the spectral element method in 3-D models. We find that the observed cross-correlat...
Article
Full-text available
We compare finite-frequency sensitivity kernels computed from ray-theoretical wavefields (“banana-doughnut” kernels) and from full waveform computations (often called “adjoint” kernels) in order to evaluate resolution, accuracy and computational cost. We focus here on body-wave seismic tomography at regional and local scales. Our results show that:...
Article
Full-text available
SUMMARYA Triangular Spectral Element Method (TSEM) is presented to simulate elastic wave propagation using an unstructured triangulation of the physical domain. TSEM makes use of a variational formulation of elastodynamics based on unstructured straight-sided triangles that allow enhanced flexibility when dealing with complex geometries and velocit...
Article
Full-text available
Site response is a critical consideration when assessing earthquake hazards. Site characterization is key to understanding site effects as influenced by seismic site conditions of the local geology. Thus, a number of geophysical site characterization methods were developed to meet the demand for accurate and cost-effective results. As a consequence...
Article
Full-text available
The goal of the work presented in a two-companion paper is to pave the way for reliably assessing the risks of damage to buildings on the shore, induced by the detonation of unexploded historical ordnance (UXO) of large weights in variable shallow water environments with a water depth less than 50 m. The risk assessment is quantified through the se...
Article
Full-text available
Distributed acoustic sensing (DAS) is an ideal tool for ambient noise tomography owing to the dense spatial measurements and the ability to continuously record in harsh environments, such as underwater. Although the fine spatial sampling of DAS facilitates the imaging of small-scale lateral velocity heterogeneities, efforts relying on dispersion-ba...
Article
The building history of a cultural heritage building and the after-effects induced by extreme loads such as earthquakes have a durable impact on its modal parameters. This article aims to discuss the peculiarities of some modal parameters extracted from ambient vibration measurements in light of the complex history of Sant’Agata del Mugello. The Ro...
Article
Full-text available
On 11 November 2019, an Mw 4.9 earthquake struck the middle Rhône valley (South-East France) producing moderate to severe damage in the town of Le Teil and its surroundings. This unexpected event stressed the vulnerability of the French cultural built heritage to a moderate seismic hazard. Commonly applied to modern civil engineering structures, pa...
Article
Full-text available
The goal of this work presented in a two-companion paper is to pave the way for reliably assessing the risks of damage to buildings on the shore, induced by the detonation of large-charge historical ordnance (i.e., countermining) in variable shallow water environments. Here, we focus on the impact of the marine environment, more specifically the un...
Article
The elastoplastic Iwan model has been used since the end of the 1970s to simulate nonlinear soil behavior in seismic wave propagation. In this work, we present an automatic algorithm to efficiently sample the shear-modulus reduction curve in function of shear deformation, which constitutes the exclusive ingredient of the elastoplastic model. This m...
Article
Full-text available
Quito, the capital of Ecuador, with more than 2.5 M inhabitants, is exposed to a high seismic hazard due to its proximity to the Pacific subduction zone and active crustal faults, both capable of generating significant earthquakes. Furthermore, the city is located in an intermontane piggy-back basin prone to seismic wave amplification. To understan...
Preprint
Distributed acoustic sensing is an ideal tool for ambient noise tomography owing to the dense spatial measurements and the ability to continuously record in harsh environments, such as underwater. We demonstrate the ability to image a complex underwater basin using ambient noise recorded on a fiber deployed offshore Greece. A two-dimensional shear-...
Conference Paper
Full-text available
In this work, a combination of passive and active seismic imaging techniques is used to image the velocity profile beneath the KUMA site. The estimation of dispersion curve of the blind exercise "Kumamoto" is based on crosscorrelations of ambient seismic noise. I calculate correlations from the entire time signals (only vertical components) of each...
Article
Full-text available
The use of distributed acoustic sensing (DAS) presents unique advantages for earthquake monitoring compared with standard seismic networks: spatially dense measurements adapted for harsh environments and designed for remote operation. However, the ability to determine earthquake source parameters using DAS is yet to be fully established. In particu...
Preprint
The use of Distributed Acoustic Sensing (DAS) presents unique advantages for earthquake monitoring compared with standard seismic networks: spatially dense measurements adapted for harsh environments and designed for remote operation. However, the ability to determine earthquake source parameters using DAS is yet to be fully established. In particu...
Article
Full-text available
We report here an interesting case study of dynamic characterization of a limestone sea cliff area, named the Sutta-Rocca overhang, located near the medieval town of Bonifacio (southern Corsica, France). The site belongs to an UNESCO protected area with an important number of visitors per year. Therefore, it is of particular interest to evaluate th...
Article
Full-text available
On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to...
Preprint
Full-text available
On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to...
Article
Full-text available
A broadband seismological station (PRIMA) installed offshore Nice airport (southeastern France) reveals a strong amplification effect of seismic waves. PRIMA station was in operation for 2 years (9/2016 to 10/2018) on the outer shelf at a water depth of 18 m. Situated at the mouth of the Var River, this zone is unstable and prone to landslides. A c...
Article
In seismic hazard studies, site effects assessment is based on an accurate knowledge of mechanical properties and geometry of superficial geological formations. The Lower Var Valley (Nice, southeastern France) is a 2 km wide fluvial sedimentary basin where site effects have been observed on earthquake recordings. In addition, this area is a signifi...
Article
The presence of multiscale interactions means that the complex urban wavefield must be observed and analyzed in order to understand seismic ground motion in urban environments. Originally called site–city interaction, the interactions between soil and structures, structures and soil, and between structures contribute to the modification of urban se...
Article
Full-text available
In this article, we propose an interpretation of the propagation velocities of the pulse wave obtained in vertical structures through seismic interferometry by deconvolution. The novelty of this article is to propose a parametric study applied to canonical finite‐element models of fixed‐base buildings from pure‐shear to pure‐bending beam‐like build...
Article
Full-text available
In December 2018, the National Aeronautics and Space Administration (NASA) Interior exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission deployed a seismometer on the surface of Mars. In preparation for the data analysis, in July 2017, the marsquake service initiated a blind test in which participants were asked to...
Article
We characterise the aftershock sequence following the 2016 Mw=7.8 Pedernales earthquake. More than 10,000 events were detected and located, with magnitudes up to 6.9. Most of the aftershock seismicity results from interplate thrust faulting, but we also observe a few normal and strike-slip mechanisms. Seismicity extends for more than 300 km along s...
Preprint
We characterise the aftershock sequence following the 2016 Mw=7.8 Pedernales earthquake. More than 10,000 events were detected and located, with magnitudes up to 6.9. Most of the aftershock seismicity results from interplate thrust faulting, but we also observe a few normal and strike-slip mechanisms. Seismicity extends for more than 300 km along s...
Article
The April 2016 Pedernales earthquake ruptured a 100 km by 40 km segment of the subduction zone along the coast of Ecuador in an M-w 7.8 megathrust event east of the intersection of the Carnegie ridge with the trench. This portion of the subduction zone has ruptured on decadal time scales in similar size and larger earthquakes, and exhibits a range...
Article
Full-text available
We propose a nodal high-order discontinuous Galerkin (DG) method for coupled wave propagation in heterogeneous elastoplastic soil columns. We solve the elastodynamic system written in velocity-strain formulation considering simultaneously the three components of motion. A 3D Iwan elastoplastic model for dry soils under dynamic loading is introduced...
Article
Full-text available
Surface wave methods gained in the past decades a primary role in many seismic projects. Specifically, they are often used to retrieve a 1D shear wave velocity model or to estimate the VS,30 at a site. The complexity of the interpretation process and the variety of possible approaches to surface wave analysis make it very hard to set a fixed standa...
Poster
Full-text available
On April 16, 2016, a large part of the Ecuadorian coast was shacked by an Mw7.8 earthquake, affecting nearly 30,000 homes and public buildings. Understanding soil characteristics of these affected areas is a necessary and useful aid to reconstruction efforts. To this end, the Instituto Geofísico at the Escuela Politécnica Nacional (IG-EPN) undertoo...
Article
Full-text available
This article presents the main results of the validation phase of the PRENOLIN project. PRENOLIN is an international benchmark on 1D nonlinear (NL) site‐response analysis. This project involved 19 teams with 23 different codes tested. It was divided into two phases; with the first phase verifying the numerical solution of these codes on idealized s...
Article
Quito, the capital city of Ecuador, with a population close to three million inhabitants, is located in an earthquake-prone region that has been struck by important events in the past. The city is built on the hanging wall of an active reverse fault, constituting a piggy-back basin filled with volcanic and fluvial origin deposits. To date, the Quit...
Article
We propose a nodal high-order discontinuous Galerkin method for 1D wave propagation in nonlinear media. We solve the elastodynamic equations written in the velocity-strain formulation and apply an upwind flux adapted to heterogeneous media with nonlinear constitutive behavior coupling stress and strain. Accuracy, convergence and stability of the me...
Article
Full-text available
The structural motion of a tall reinforced concrete (RC) building on alluvial soil in Nice (France) is continuously recorded using accelerometers. The structural behavior of the building is studied using operational modal analysis (OMA) to identify its dynamic properties, a finite element (FE) model to reproduce the building response, and empirical...
Article
A megathrust subduction earthquake (Mw7.8) struck the coast of Ecuador on April 16th, 2016 at 23h58 UTC. This earthquake is one of the best-recorded megathrust events up to date. Besides the mainshock, two large aftershocks have been recorded on May 18th, 2016, at 7h57 (Mw 6.7) and 16h46 (Mw6.9). These data make a significant contribution for under...
Article
In this study, we analyze the acceleration time histories data at the Belleplaine (Guadeloupe, French West Indies) vertical array, recorded between 2008 and 2014, to evaluate the seismic response of sediments. First, we apply seismic interferometry by deconvolution method to compute the in-situ shear wave velocity between the sensor at the surface...
Conference Paper
Full-text available
The city of Quito has been damaged several times in the past by important earthquakes. The seismic hazard assessment is thus an important issue and especially, the site effect question. The Quito basin deep structure remains unknown and the potential impact of seismic waves has yet to be evaluated. The National Accelerometric Network (RENAC) that b...
Article
Full-text available
PREdiction of NOn-LINear soil behavior (PRENOLIN) is an international benchmark aiming to test multiple numerical simulation codes that are capable of predicting nonlinear seismic site response with various constitutive models. One of the objectives of this project is the assessment of the uncertainties associated with nonlinear simulation of 1D si...
Conference Paper
Full-text available
The Pedernales Mw7.8 earthquake that occurred on the subduction interface between the Nazca plate and the Southamerican plate on April 16th 2016 caused extensive damages to several coastal cities of Ecuador. The event was well recorded by a large number of accelerometric stations both in the near field and all over the country. A total of 62 record...
Article
Full-text available
The main scope of the InterPACIFIC (Intercomparison of methods for site parameter and velocity profile characterization) project is to assess the reliability of in-hole and surface-wave methods, used for estimating shear wave velocity. Three test-sites with different subsurface conditions were chosen: a soft soil, a stiff soil and a rock outcrop. T...
Conference Paper
Full-text available
The Nice prefecture is equipped by 24 accelerometric sensors, located at different levels, which continuously record the building response. A finite element model of the building is created based in design plans and information about materials provided during the conception project. Such model is used to obtain the natural frequencies of the struct...
Article
Full-text available
Analysis of ambient vibration records enables the dynamic structural behaviour identification trough Operational Modal Analysis (OMA) techniques. This study uses a set of recordings of a 22-storey Reinforced Concrete (RC) building in Nice (France), where no remarkable damages are detected since it is instrumented. Signals acquired using acceleromet...
Technical Report
Full-text available
Le projet a pour objectif l'identification des propriétés dynamiques du bâti existant à partir des enregistrements sismologiques. Une connaissance précise de ces paramètres (fréquences modales et vitesse de propagation des ondes) permet de définir empiriquement la réponse dynamique de la structure. Ces paramètres varient dans différents contextes m...
Article
The devil's checkerboard: why cross-correlation delay times require a finite frequency interpretation
Article
Full-text available
We present an extension of the nodal discontinuous Galerkin method for elastic wave propagation to high interpolation orders and arbitrary heterogeneous media. The high-order lagrangian interpolation is based on a set of nodes with excellent interpolation properties in the standard triangular element. In order to take into account highly variable g...
Article
Full-text available
p>Rapid-response seismic networks are an important element in the response to seismic crises. They temporarily improve the detection performance of permanent monitoring systems during seismic sequences. The improvement in earthquake detection and location capabilities can be important for decision makers to assess the current situation, and can pro...