Françoise Courboulex

• Phd
• Research Director at Université Côte d'Azur CNRS

Recent developments in Distributed Acoustic Sensing (DAS) have greatly expanded our capabilities for dense geophysical instrumentation by tapping into existing (but unused) fibre-optic telecommunication networks. Leveraging these so-called "dark fibres" permits an extremely rapid deployment of thousands of vibration sensors over distances of severa...

Earthquake‐triggered landslides are a severe hazard and contribute to landscape evolution. To understand their process and controlling factors, we model the onset of seismically‐triggered slip on pre‐existing slip surfaces governed by laboratory‐based rate‐and‐state friction, including wave propagation effects. Through numerical simulations and the...

Un séisme (appelé aussi tremblement de terre) est dû à un glissement rapide de deux compartiments rocheux situés de part et d'autre d'une faille. C'est le frottement entre ces deux compartiments qui va produire des ondes se propageant jusqu'à la surface du globe. C'est un phénomène bref (de quelques secondes pour les séismes faibles à modérés à que...

Earthquake-triggered landslides are a severe hazard and contribute to landscape evolution. To understand their process and controlling factors, we model the onset of seismically-triggered slip on pre-existing slip surfaces governed by laboratory-based rate-and-state friction, including wave propagation effects. Through numerical simulations and the...

Recent developments in Distributed Acoustic Sensing (DAS) have greatly expanded our capabilities for dense geophysical instrumentation by tapping into existing (but unused) fibre-optic telecommunication networks. Leveraging these so-called "dark fibres" permits an extremely rapid deployment of thousands of vibration sensors over distances of severa...

Seismic monitoring in Haiti is currently provided by a mixed network of low-cost Raspberry Shake (RS) seismic stations hosted by citizens, and short-period and broadband stations located mainly in neighboring countries. The level of earthquake detection is constantly improving for a better spatio-temporal distribution of seismicity as the number of...

The 14 August 2021 Mw 7.2 Haiti earthquake struck 11 yr after the devastating 2010 event within the Enriquillo Plantain Garden (EPG) fault zone in the Southern peninsula of Haiti. Space geodetic results show that the rupture is composed of both left-lateral strike-slip and thrust motion, similar to the 2010 rupture; but aftershock locations from a...

On 2 October 2020, the Maritime Alps in southern France were struck by the devastating Storm Alex, which caused locally more than 600 mm of rain in less than 24 h. The extreme rainfall and flooding destroyed regional rain and stream gauges. That hinders our understanding of the spatial and temporal dynamics of rainfall–runoff processes during the s...

The August 14, Mw7.2, Nippes earthquake in Haiti occurred within the same fault zone as its devastating, Mw7.0, 2010 predecessor but struck the country when field access was limited by insecurity and conventional seismometers from the national network were inoperative. A network of citizen seismometers installed in 2019 provided near-field data cri...

In 1906, an earthquake with a magnitude estimated between Mw 8.4 and 8.8 occurred in the subduction zone along the coast of Ecuador and Colombia. This earthquake caused extensive damage on the coast but had a rather small impact on the capital city of Quito, situated 180 km away. At that time, the city of Quito extended over a small area with a few...

On October 2, 2020, the Maritime Alps in southern France were struck by the devastating storm Alex that caused locally more than 600 mm of rain in less than 24 hours. The extreme rainfall and flooding destroyed regional rain and stream gauges. That hinders our understanding of the spatial and temporal dynamics of rainfall-runoff processes during th...

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...

The Ubaye Region is the most seismically active region in the Western Alps, with earthquakes that were commonly felt by the population and that even damaged local villages and cities. Since the first testimonies in 1844, this area has been regularly struck by seismic swarms with a high number of events, such as in 2003-2004 or 2012-2015, or by main...

The analysis of the seismicity catalog (1996 to 2019) covering the region from the Jura mountains to Corsica provides a first-order image of the distribution of earthquakes, highlighting large structures such as the Briançonnais and Piedmontais seismic arcs, the eastward deepening of the focal depths through the Western Alps, several large active f...

An educational program focusing on seismological activities for school and university students that trains in observational sciences and raises citizen awareness of natural hazards has been active in France since 1995. Over this quarter century, different generations of students have learned various lessons concerning instrument installation, data...

Earthquake risk reduction approaches classically apply a top-down model where scientific information is processed to deliver risk mitigation measures and policies understandable by all, while shielding end-users from the initial, possibly complex, information. Alternative community-based models exist but are rarely applied at a large scale and rely...

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...

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...

An educational program focusing on seismological activities for student training in observational sciences and on raising citizen awareness of natural hazards has been active in France since 1995. Over this quarter century, different generations of students have learnt various lessons concerning instrument installation, data recording and analysis....

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...

On 26 November 2019, SEIS, the first broadband seismometer designed for the Martian environment (Lognonné et al., 2019) landed on Mars, thanks to National Aeronautics and Space Administration’s (NASA’s) InSight mission. On 6 April 2019 (sol 128), the InSight Science team detected the first historical “marsquake” (NASA news release). Before it was r...

We evaluate the non-linear site response at the stations of the Japanese Kik-Net network by computing the ratio between the Fourier spectra of the recordings at the surface and at the downhole station. When the amplitude of the input signal increases, we observe a shift of the resonance peaks towards lower frequencies, characteristic of non-linear...

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...

A network of “personal seismometers” is intended to complement Haiti’s national seismic network to engage and inform residents about earthquake hazards and preparation.

The upper part of the Ubaye Valley (French Alps) is characterized by alternating mainshock‐aftershock sequences and swarms. Particularly, during the 2012–2015 crisis, four mainshocks with Ml > 3.5 occurred. We here focus on the aftershocks of the largest one (Ml = 4.8, 7 April 2014), in order to better understand the involved processes behind this...

Complex networks of high-tech sensors are tough to operate and maintain in developing countries – but new low-costs, low-maintenance instruments may help. Because they are “connected objects” they also provide new opportunities to engage the civil society in citizen-science. Here we describe a seismological instrumentation experiment in Haiti with...

Complex networks of high-tech sensors are tough to operate and maintain in developing countries – but new low-costs, low-maintenance instruments may help. Because they are “connected objects” they also provide new opportunities to engage the civil society in citizen-science. Here we describe a seismological instrumentation experiment in Haiti with...

The shallow Nice submarine slope is notorious for the 1979 tsunamigenic landslide that caused eight casualties and severe infrastructural damage. Many previous studies have tackled the question whether earthquake shaking would lead to slope failure and a repetition of the deadly scenario in the region. The answers are controversial. In this study,...

Seismic ground motion is strongly dependent on the site geotechnical characteristics. This phenomenon must be considering in risk mitigation through the evaluation of soil response. The soil response to a cyclic solicitation is not only depending on the soil parameters but also on the level of the shaking. This non-linear behavior is especially imp...

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...

Application of the SCARDEC method provides the apparent source time functions together with seismic moment, depth, and focal mechanism, for most of the recent earthquakes with magnitude larger than 5.6-6. Using this large dataset, we have developed a method to systematically invert for the rupture direction and average rupture velocity V r, when un...

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...

We develop a new approach to image earthquake rupture from strong motion data. We use a large dataset of aftershock waveforms, interpolated over the seismic fault to obtain Green's function approximations. Next we deploy a Bayesian inversion method to characterize the slip distribution, the rupture velocity, the slip duration and their uncertaintie...

Seismic ground motion is strongly dependent on the site geotechnical characteristics. This phenomenon must be taking into account in risk mitigation through the evaluation of soil response. The soil response to a cyclic solicitation is not only depending on the soil parameters but also on the level of the shaking. This non-linear behavior is especi...

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...

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...

We use the new global database of source time functions (STFs) and focal mechanisms proposed by Vallée (2013) using the automatic SCARDEC method (Vallée et al., 2011) to constrain earthquake rupture duration and variability. This database has the advantage of being very consistent since all the events with moment magnitudes Mw>5.8 that have occurre...

Time-series bathymetric data acquired from 1967 to 2011 are used to evaluate the morphological evolution of the continental shelf and upper continental slope off the city of Nice (SE France, Ligurian Sea). Mapping in water depths of 0–300 m was undertaken to identify the changing morphology of landslide scars and their erosive chutes. Quantitative...

The two main earthquakes that occurred in 2012 (May 20 and 29) in the Reggio-Emiliano region (Northern Italy) were relatively small (Mw 6.1 and Mw 5.9) but they generated unexpected damages in a large area around the epicenter. On some stations, the observed seismic levels exceeded design levels recommended by the EC8 seismic code for buildings and...

To provide better insight into seismic ground motion in the Port-au- Prince metropolitan area, we investigate site effects at 12 seismological stations by analyzing 78 earthquakes with magnitude smaller than 5 that occurred between 2010 and 2013. Horizontal-to-vertical spectral ratio on earthquake recordings and a standard spectral ratio were appli...

A new seismically active zone is found in the southern part of the Ligurian basin, 80-km west of Corsica (western Mediterranean). The activity began in February 2011 with a foreshock (ML 4) and a mainshock (ML 5.3) 5 days later, followed by numerous aftershocks. We first analyze the fore- and mainshock in detail. We compare the results obtained usi...

We study the physical causes of the magnitude dependence of ground-motion decay with distance that is observed on real data. Using stochastic simulations, we analyze the role played by anelastic attenuation Q (f), path duration, site effect (K0), finite-fault effect, and stress drop for a magnitude range between 4 and 7. We systematically look at p...

La région de l'Ubaye, connue pour ses crises sismiques (Jenatton et al. 2007), a subi les deux plus forts séismes observés en France métropolitaine depuis 2011. Le premier, de magnitude ML=4.9 (Mw=4.1), a eu lieu le 26 février 2012, le second, de magnitude ML=5.2 (Mw=4.8), le 7 avril 2014. Les deux épicentres sont séparés par moins de 1 km. Ces séi...

We use the new global database of Source Time Functions (STF) and focal mechanisms proposed by Vallée (2013) using the automatic SCARDEC method (Vallée et al, 2011) to constrain the earthquakes rupture duration and its variability. This database has the advantage of being very consistent since all events with Mw> 5.8 that occurred during the last 2...

We use the new global database of Source Time Functions (STF) and focal mechanisms proposed by Vallée (2013) using the automatic SCARDEC method (Vallée et al, 2011) to constrain the earthquakes rupture duration and its variability. This database has the advantage of being very consistent since all events with Mw> 5.8 that occurred during the last 2...

Ongoing evidence for earthquake clustering calls for records of numerous earthquake cycles to improve seismic hazard assessment, especially where recurrence times overstep historical records. We show that most turbidites emplaced at the Africa-Eurasia plate boundary off west Algeria over the past ~8 k.y. correlate across sites fed by independent se...

Seismic hazard assessment is a critical but challenging issue for modern societies. A key parameter to be estimated is the recurrence interval of damaging earthquakes. This requires the establishment of earthquake records long enough to be relevant, i.e. far longer than historical observations. We study how lake sediments can be used for this purpo...

The original and innovative aspect of this programme stems from giving students the opportunity to install a seismometer in their school. The recorded signals, reflecting regional or global seismic activity, feed into an on-line database, a genuine seismic resource centre and a springboard for educational and scientific activities. The network ’Edu...

Le 07/07/2011 un séisme modéré (ML 5,4) s’est produit 80 km à l’ouest d’Ajaccio dans une zone où la sismicité instrumentale semble très faible. Cet événement est le plus important d’une série de 6 séismes modérés (3,8<ML<5,4) qui se sont produit dans cette zone depuis juillet 2011. Cette séquence sismique est localisée dans le bassin océanique Ligu...

Time-series bathymetric data acquired between 1991 and 2011 have been used to evaluate the recent morphological evolution of the Nice upper continental slope (SE France, Ligurian Sea). Small-scale landslides lead to a retrogressive evolution of the continental shelf/upper slope transition but their frequency, size and impact are not well known. Map...

On April 7 th 2014, an earthquake of magnitude Mw 4.9 stroke the Ubaye valley in the French Alps. It was one of the largest events well recorded in the Alps since the damaging earthquake that occurred close to Annecy in 1996 [Courboulex et al., 1999; Thouvenot et al., 1998]. We computed its moment magnitude (Mw 4.9) and its focal mechanism that dep...

This chapter provides an overview of the last two decades’ European experiences in educational seismology and describes the different contexts in which they have been developed. The basic idea of these educational projects is that seismology may represent an efficient communication vehicle for teaching a wide range of basic earth science topics thr...

We document a moderate earthquake in the French Alps (26 February 2012 M w 4.1) that has been much more distinctly felt south of the event than north of it. This discrepancy was especially clear in the two large cities of Nice and Grenoble, both situated at 100 km from the epicenter. This observation was confirmed by ground-motion measurements that...

During one month, in October and November 2010, the region of Sampeyre (Western Alps, Italy) was struck by a seismic activity of several hundred events. The location of 287 events recorded at least by three stations showed a diffuse swarm ranging between 8 and 13 km depth. The number of earthquakes in the database was increased thanks to a detailed...

preliminary results on size and impact of small-size landslides presented to ISSMMTC

Can the directivity effect of a rupture process be detected by the population 100 km away for a moderate size Mw 4.1 earthquake? The February 26th 2012, earthquake that occurred in the French Alps proved that it can ! During the night of February 26, 2012, the inhabitants and winter holidaymakers of the Vallée de l'Ubaye in the French Alps were wok...

Ground motion decay with distance presents a clear magnitude dependence, PGA values of small events decreasing faster than those of larger events. This observation is now widely accepted and often taken into account in recent ground motion prediction equations (Anderson 2005, Akkar & Bommer 2010). The aim of this study is to investigate the origin...

We present the preliminary results of a study with the aim of understanding how some combinations of source and site effects can generate extreme ground motions in the city of Port au Prince. For this study, we have used the recordings of several tens of earthquakes with magnitude larger than 3.0 at 3 to 14 stations from three networks: 3 stations...

Earthquakes are both troubling and fascinating because of their suddenness, the terrible destruction they can wreak and because they still remain unpredictable. This is why emphasis must be placed on preparation, especially in the school system where causes and effects of these hazards are studied. But trying to explain earthquakes, scrutinizing th...

Plusieurs failles actives sont identifiées à la jonction Alpes – Bassin Ligure : des failles dont la longueur est de l’ordre de la dizaine de kilomètres à terre (Faille de Blausasc, Faille de Donareo, Faille de Saorge-Taggia) et en mer le système de faille nord Ligure dont la longueur totale atteint 80 km. La géométrie et la cinématique de ces fail...

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...

After each large destructive earthquake in the world, shocking images are presented to the adults and children on the TV and through the Internet. All sorts of questions arise: Some of them are very rational, whereas others are driven by fear of a global catastrophe or even a curse. For example, in March 2011, after the giant Tohoku, Japan, earthqu...

In regions where only small- to moderate-size events have been recorded, it is important to be able to anticipate the effects of a large event by simulating the ground motion it may generate. Using the very good records of two small earthquakes that occurred in the central French Pyrenees (2007 November 15, Mw= 3.6; and 2006 November 17, Mw= 4.5),...

The lower Var valley is the only large outcropping zone of Plio-Quaternary terrains throughout the southwestern Alps. In order to assess the seismic hazard for the Alps - Ligurian basin junction, we investigated this area to provide a record of earthquakes that have recently occurred near the city of Nice. Although no historical seismicity has been...

In lines with diverse initiatives regarding scientific culture and education, the `O3E' experience (http://O3E.geoazur.eu) has set up a permanent educational network of schools in the Alpine and Mediterranean areas, building an exchange of knowledge on natural risks prevention. The ``O3E'' innovative project (European Educational Observatory for En...

The southern Alps–Ligurian basin junction is one of the most seismically active zone of the western Europe. A constant microseismicity and moderate size events (3.5 < M < 5) are regularly recorded. The last reported historical event took place in February 1887 and reached an estimated magnitude between 6 and 6.5, causing human losses and extensive...

As dramatically reminded during the last days by the Haiti disaster, earthquakes are traumatic events as storms or floods. They cause more damages when population don't have the knowledge of these phenomena and doesn't know how to deal with it. Presently, it's not possible to predict an earthquakes or extreme meteorological events. Preparation stay...

The North-Ligurian rifted margin is singular in that it lies immediately next to the Alpine orogenic arc. It is furthermore seismically active and can experience destructive earthquakes such as in 1887 in the region of Imperia—an event that resulted in a tsunami and more than 600 casualties in spite of a coastal area that was much less densely popu...

Small earthquakes are not destructive but can be very helpful. This HDR thesis describes threw different research studies how small earthquakes can be used for (1) understanding seismic source of larger ones by an inversion using empirical Green's functions (2) imaging active faults using location and relative relocation methods (3) predict the gro...

The validity and the stability of a ground-motion simulation method based on the recordings of a single small event as an empirical Green's function (EGF) is tested on a seismic crisis that occurred 25 km offshore of the Guadeloupe Islands (Caribbean arc). We aim to determine if (1) the method enables us to reproduce the observed ground motion, (2)...

Les petits séismes ne sont pas destructeurs, ils font peu parler d'eux, pourtant ils sont très utiles. Ce mémoire d'HDR décrit à travers plusieurs travaux de recherche comment les petits séismes peuvent être utilisés pour (1) comprendre la source des séismes plus importants par un processus d'inversion des fonctions de Green empiriques (2) imager l...

On April 6th, 2009 the L'Aquila earthquake Mw6.3 struck the Abruzzo region (Central Italy) and was at the origin of heavy damages and human losses. This destructive mainshock was followed by numerous aftershocks recorded by a large number of accelerometric stations of the Italian Strong Motion Network (RAN). The aim of this study is to simulate the...

Although the Pyrenean range is characterized by a moderate seismic activity, it has been affected by strong earthquakes in the past. One of the most destructive historical event occurred on June 21, 1660, in the Central French Pyrenees near the pilgrimage city of Lourdes, with an epicentral intensity of VIII-IX (on MSK 1964 scale) and a magnitude e...

Earthquakes are both troubling and fascinating because of their suddenness and the terrible destruction they can wreak. However, a seismic wave cannot be touched, the Earth's interior cannot be seen and, earthquakes cannot be predicted ... By installing seismic stations in schools, the `Sismos à l'Ecole' project enables teachers, children and stude...

Earthquakes may be traumatic events and as many other environmental emergencies, like storm or floods, may cause more damages than expected when who experiences the phenomena does not know how to behave in the fall. Provided that it is always not feasible to rely on prediction when dealing with earthquakes or extreme meteorological events, prepared...

A key step in probabilistic seismic-hazard assessment is the prediction of expected ground motions produced by the seismic sources. Most probabilistic studies use a ground-motion prediction model to perform this estimation. The present study aims at testing the use of simulations in the probabilistic analysis instead of ground-motion models. The me...

Although the Pyrenean range is characterized by a moderate seismic activity, it has been affected by strong earthquakes in the past. One of the most destructive event occurred in the Bigorre region (Central French Pyrenees) on June 21, 1660, with a maximum macroseismic intensity of IX and a magnitude 6.1 inferred from isoseists. If such an earthqua...

Ahead of the quick evolution of our society, in which scientific information has to be accurately understood by a great majority, the promotion of a responsible behaviour coming from educated and trained citizens has become a priority. One of the roles of school is to enable children to understand sciences, these same sciences that were long ago th...

The Guadeloupe Island situated in the Caribbean arc has been struck in November 2004 by a Mw 6.4 earthquake that occurred 20km offshore on a shallow crustal fault. This event caused the death of one person and serious damages to several buildings. The mainshock has been followed by a large number of aftershocks including about 20 events of magnitud...

We present here a detailed analysis of a seismic data set recorded by a dense seismological network installed over 6 months in the southeast of France. This experiment was set-up at the boundary between the Ligurian basin and the southern subalpine thrust belt (the Nice arc), which is a complex tectonic region that undergoes low to moderate seismic...

We present here a detailed analysis of a seismic data set recorded by a dense seismological network installed over 6 months in the southeast of France. This experiment was set-up at the boundary between the Ligurian basin and the southern subalpine thrust belt (the Nice arc), which is a complex tectonic region that undergoes low to moderate seismic...

An analysis of the Zihuatanejo, Mexico, earthquake of 1994 December 10 (M= 6.6), based on teleseismic and near-source data, shows that it was a normal-faulting, intermediate-depth (H= 50 ± 5 km) event. It was located about 30 km inland, within the subducted Cocos plate. The preferred fault plane has an azimuth of 130°, a dip of 79° and a rake of −8...

Numéro spécial du BLPC sur les risques sismiques, 2007

Bulletin of the Seismological Society of America, v. 95, n. 4, p. 1387-1400, 2005. http://dx.doi.org/10.1785/0120040211

Slip distributions of the moderate magnitude (Mw 5.9), 1999 Athens earthquake, inverted from surface waves and interferometric Synthetic Aperture Radar (SAR) images, show very different characteristics. The robustness analysis proposed in this study, confirms the discrepancy between the well-constrained features of each individual solution. Irrespe...

We investigate the rupture history of the three largest magnitude earthquakes of the 1997 Umbria-Marche sequence by inverting GPS, DInSAR and near-source strong motion waveforms. We use the frequency domain inversion procedure proposed by Cotton and Campillo (1995) and calculate the Green s functions for a layered halfspace using the discrete waven...

We investigate the rupture history of the three largest magnitude earthquakes of the 1997 Umbria-Marche sequence by inverting GPS, DInSAR and near-source strong motion waveforms. We use the frequency domain inversion procedure proposed by Cotton and Campillo (1995) and calculate the Green’s functions for a layered halfspace using the discrete waven...