Denis Moiriat

• Ph. D
• Engineering geologist / Geotechnical site engineer at Institut de Radioprotection et de Sûreté Nucléaire (IRSN France)

During the Petrinja earthquake sequence in December 2020, numerous liquefied sand ejections came to the surface along the Kupa, Sava and Glina rivers in Quaternary alluvial sediments. In October 2022, we performed field investigation in the epicentral area, involving geotechnical and geophysical techniques, at different sites with sand ejecta or la...

In certain geological settings such as sedimentary basins, the ground motion induced by an earthquake may be amplified by local site conditions. Estimating these site effects is important for seismic hazard assessment but can be difficult to do empirically due to the scarcity of site-specific field data in time and space, especially in low-to-moder...

The Dynamic Variable Energy Penetrometer (P.A.N.D.A® or P.A.N.D.A.3®) allows an estimation of soil properties almost continuously with depth. This lightweight tool also has the advantage of being able to be rapidly deployed on sites with difficult access. This work presents an example of its implementation on the island of Cephalonia (western Greec...

The occurrence of extensive liquefaction during the 2020 Petrinja earthquake in the epi-central area raises many questions, notably the geometries of sedimentary bodies in depth. In the fluvial plains of the Kupa, Glina and Sava rivers, many lines of sand ejecta and cracks at the surface are subparallel to the riverbanks in convex meanders and woul...

During the Petrinja earthquake sequence in December 2020, numerous liquefied sand ejections came to the surface along the Kupa, Sava and Glina rivers in Quaternary alluvial sediments. In October 2022, we performed field investigation in the epicentral area, involving geotechnical and geophysical techniques, at different sites with sand ejecta or la...

In the area of soil behaviour under earthquakes, this work sought to specify the dynamic properties of alluvial soils in the vicinity of a nuclear site. The initial aim was to study, after a phase of data collection in the archives, the extent to which data from in situ or laboratory geotechnical tests could provide relevant information, in particu...

Earthquake-induced liquefaction is one of the main causes of levee breaches that can threaten human life and property. Conventionally, liquefaction hazard has been assessed in terms of the factor of safety FoS against liquefaction which ignores the potential variability of groundwater table (GWT) due to precipitation events. A probabilistic methodo...

The Albanian earthquake of November 26, 2019 with Mw magnitude of 6.4 caused severe impacts in Durrës city built above a Plio-Quaternary basin. The damaged buildings are the consequences of several factors including strong ground motion, local site amplification, poor building workmanship and soil liquefaction. This last phenomenon occurred along t...

The so-called site effects caused by superficial geological layers may be responsible for strong ground motion amplification in certain configurations. We focus here on the industrialized Tricastin area, in the French Rhône valley, where a nuclear site is located. This area lies above an ancient Rhône Canyon whose lithology and geometry make it pro...

This Cahier Technique has been produced under the aegis of the French Association for Earthquake Engineering (AFPS). It is an 'Earthquake Geotechnics' handbook providing an overview of the topic of earthquake-induced soil liquefaction. It follows on from Cahier Technique CT no. 22 describing the application of the PS92 rules (AFPS, 2001) and the Gu...

Ce Cahier Technique a été réalisé sous l'égide de l’Association Française de Génie Parasismique (AFPS). Il s’agit d’un cahier de "Géotechnique Sismique" qui propose un panorama sur le thème de la liquéfaction des sols sous l'effet de séismes. Il s'inscrit dans la continuité du Cahier Technique CT n°22 qui détaille l’application des règles PS92 (AFP...

Des méthodes simplifiées permettent d'évaluer les tassements post-liquéfaction des sables sous nappe à partir des essais géotechniques in situ de type SPT ou CPT, et des facteurs de sécurité à la liquéfaction FSL obtenus par application de la méthode simplifiée de Seed. Pour chaque type d'essai SPT ou CPT, cet article compare les résultats de deux...

Dans la pratique courante, la quantification du risque de liquéfaction des sols sous l'effet de séismes passe par l'utilisation de la méthode simplifiée appliquée aux essais in situ de type SPT ou CPT. Initialement proposée par Seed et Idriss en 1971, cette méthode permet d'estimer des coefficients de sécurité vis-à-vis de ce risque (F Sl). La méth...

This work is a multidisciplinary approach from geological and geophysical surveys to build a 3D geological model of Argostoli Basin (Cephalonia Island, Greece) aiming to be used for computational 3D simulation of seismic motion. Cephalonia Island is located at the north-western end of the Aegean subduction frontal thrust that is linked to the dextr...

The Holocene sedimentary record of the flood plain of the Saint-Ciers-Sur-Gironde marsh was examined on sediment cores from the right bank of the Gironde estuary with regard to the evolution of the marsh and its potential to preserve high-energy deposits. Sedimentological, geochemical, geophysical and micropaleontological methods were applied. Radi...

The ARGOstoli NETwork (ARGONET) consists of a vertical seismic array and a close by (440 m) free-field station on bedrock, located in Cephalonia, western Greece, in the vicinity of the Cephalonia transform fault zone (CTFZ) that is characterized by a high seismic activity, one of the highest in Europe. It is intended to investigate the effects of l...

The Cephalonia Island (Greece) area is located at the northwestern end of the Aegean subduction frontal thrust linked to the dextral Cephalonia Transform Fault (CTF west of Cephalonia). Since the mean slip rate and the CTF length are large, seismic hazard is high in terms of earthquake frequency and magnitude. The Koutavos-Argostoli site was select...

Article bulletin de liaison des laboratoires des Ponts et Chaussées

Le site d'Argostoli-Koutavos (Céphalonie, Grèce) a été sélectionné dans le cadre du projet ANR-PIA SINAPS@ (www.institut-seism.fr/projets/sinaps/) pour faire l'objet d'une instrumentation longue durée en réseau accélérométrique vertical. Le but à long terme est de valider les codes de simulation numérique 3D non-linéaires. Cet article présente briè...

The study of a former underground chalk quarry at Meudon (the "Brillants" site), southwest of Paris, has indicated the presence of two main fracture families. One is attributed to the influence of a valley excavation located in the immediate vicinity of the quarry. The frequency of these fractures increases near the slope; the dip of their median p...

L’archipel de Mayotte (Collectivité départementale française de l'océan Indien) est exposé à plusieurs types d’aléas naturels, qui résultent des contextes géologique et géographique de l'archipel. Le climat chaud et humide favorise l'altération des roches volcaniques, tandis que l'intensité des précipitations et parfois des cyclones contribue à l'é...

Stability of derelict underground quarries: Study and The storage of extra earth-moving from a road-building project over an abandoned underground mine was utilized in order to study site behavior, in terms of both accelerated ageing and deformation trends when exposed to the effect of excess load. Once the initial damage state had been visually ev...