Philippe Vernant

Philippe Vernant
Université de Montpellier | UM1 · Geosciences Montpellier

PhD

About

144
Publications
36,184
Reads
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8,833
Citations
Citations since 2017
36 Research Items
4077 Citations
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
20172018201920202021202220230200400600800
Additional affiliations
September 2006 - present
French National Centre for Scientific Research
Position
  • Professor (Associate)
May 2004 - August 2006
Massachusetts Institute of Technology

Publications

Publications (144)
Conference Paper
Full-text available
Earthquakes occur in stable continental regions (SCR) with Mw>5 and up to Mw≈7, and research on the origins of SCR seismicity is ongoing. Glacial Isostatic Adjustment (GIA) is commonly considered as a factor of SCR stress perturbation that can trigger seismicity in past glaciated areas, and studies suggest that fault failure may occur around those...
Article
Le paysage ardéchois est marqué par une zone de hauts plateaux cristallins au nord-ouest (altitude de l'ordre de 1000 à 1200 m) et une zone de plateaux calcaires de plus faible altitude (~ 300 m) au sud-est dominant la vallée du Rhône (~ 70 m). D'après les études géomorphologiques et géologiques précédentes, ces reliefs seraient principalement liés...
Preprint
Seismicity is observed in Stable Continental Regions (SCR) with Mw>5 and up to Mw≈7, and research on the origins of SCR seismicity is ongoing. Glacial Isostatic Adjustment (GIA) is commonly considered as a factor of SCR deformation and stress perturbation that can trigger fault failure in glaciated areas. Studies suggest that fault reactivation due...
Preprint
Full-text available
The understanding of the origins of seismicity in intraplate regions is crucial to better characterize seismic hazards. In formerly glaciated regions such as Fennoscandia North America or the Western Alps, stress perturbations from Glacial Isostatic Adjustment (GIA) have been proposed as a major cause of large earthquakes. In this study, we focus o...
Article
Full-text available
The salt mining industrial exploitation located in Vauvert (France) has been injecting water at high pressure into wells to dissolve salt layers at depth. The extracted brine has been used in the chemical industry for more than 30 years, inducing a subsidence of the surface. Yearly leveling surveys have monitored the deformation since 1996. This da...
Article
New burial ages of cave deposits, based on the 26Al/10Be cosmogenic isotope ratio technique, from three caves in the Vis Valley, located in the south-east perimeter of the “Grands-Causses” in southern France are challenging the validity of classic karstic evolution models to explain the structure and evolution of the karstic network in the region....
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...
Preprint
Full-text available
The salt mining industrial exploitation located in Vauvert (France) has been injecting water at high pressure in wells to dissolve salt layers at depth. The extracted brine is used in chemical industry for more than thirty years, inducing a subsidence of the surface. Yearly levelling surveys monitor the deformation since the 1996. This dataset is s...
Conference Paper
Full-text available
Although more and more processes are discussed and discovered on the genesis and evolution of cave systems, the tiered karsts are often explained by a control of the base level evolution. In this classical model, the horizontal galleries are explained by a stability of the base level elevation. To the contrary, the shafts and network segments with...
Conference Paper
Full-text available
In the 60's, the formulation of the plate tectonic theory changed our understanding of the Earth dynamics. Aiming at explaining the earth first order kinematics, this primary theory of plate tectonic assumed rigid plates, a necessity to efficiently transfer stress from one boundary to another. If successful to explain, at first order, the plate-bou...
Article
Full-text available
The evolution of intraplate orogens is still poorly understood. Yet, it is of major importance for understanding the Earth and plate dynamics, as well as the link between surface and deep geodynamic processes. The French Massif Central is an intraplate orogen with a mean elevation of 1000 m, with the highest peak elevations ranging from 1500 to 188...
Article
Full-text available
We use 2 decades of data from a dense geodetic network to extract regionally coherent velocities and deformation rates in France and neighboring western European countries. This analysis is combined with statistical tests on synthetic data to quantify the deformation detection thresholds and significance levels. By combining two distinct methods –...
Article
Full-text available
The evolution of intra-plate orogens is still poorly understood. Yet, this is of major importance for understanding the Earth and plate dynamic, as well as the link between surface and deep geodynamic processes. The French Massif Central is an intraplate orogen with a mean elevation of 1000 m, with the highest peak elevations ranging from 1500 m to...
Article
Full-text available
We use dense geodetic networks and large GPS datasets to extract regionally coherent velocities and deformation rates in France and neighboring Western Europe. This analysis is combined with statistical tests on synthetic data to quantify the deformation detection thresholds and significance levels. By combining two distinct methods, Gaussian smoot...
Poster
Full-text available
We present a 3D crustal deformation velocity field of the Iberian Peninsula based on the analysis of more than 400 continuous GPS stations covering the period from 2010 to 2018 and distributed throughout the Iberian Peninsula, northern Africa and southern France. We describe the procedures followed to obtain a combined uniform velocity solution fro...
Conference Paper
Full-text available
Global Navigation Satellite System (GNSS) is a powerful tool to decipher the present-day deformation along plate boundaries, but it is usually overlooked in slow deformation regions because of the resolution limit. France is a part of the Western Eurasian plate and is commonly considered stable or having low velocities in terms of horizontal motion...
Article
Full-text available
We use statistical analyses of synthetic position time series to estimate the potential precision of GPS (Global Positioning System) velocities. The synthetic series represent the standard range of noise, seasonal, and position offset characteristics, leaving aside extreme values. This analysis is combined with a new simple method for automatic off...
Article
Full-text available
We present the most extensive and up-to-date unified GPS velocity field for Iran. We processed the data collected during 10 years (2006–2015) from the Iranian Permanent GNSS Network (IPGN) and combined them with previously published velocity solutions from GPS survey measurements during 1997–2013. We analysed this velocity field using a continuum a...
Article
The availability of GPS survey data spanning 22 years, along with several independent velocity solutions including up to 16 years of permanent GPS data, presents a unique opportunity to search for persistent (and thus reliable) deformation patterns in the Western Alps, which in turn allow a reinterpretation of the active tectonics of this region. W...
Poster
Full-text available
The present-day horizontal movements in Morocco have been the subject of several studies using two decades of GPS measurements. These studies suggested models on the geodynamic processes in the western Mediterranean region. However, vertical movements, often of smaller magnitude, are still poorly constrained. In this work we use continuous GPS meas...
Article
Full-text available
We use statistical analyses of synthetic position time series to estimate the potential precision of GPS velocities. The synthetic series represent the standard range of noise, seasonal, and position offset characteristics, leaving aside extreme values. This analysis is combined with a new simple method for automatic offset detection that allows an...
Article
The availability of GPS survey data spanning 22 years, along with several independent velocity solutions including up to 16 years of permanent GPS data, presents a unique opportunity to search for persistent (and thus reliable) deformation patterns in the Western Alps, which in turn allow a reinterpretation of the active tectonics of this region. W...
Article
Full-text available
The magnitude of epikarstic water storage variation is evaluated in various karst settings using a relative spring gravimeter. Gravity measurements are performed over a 1.5-year period at the surface and inside caves at different depths on three karst hydro-systems in southern France: two limestone karst systems and one dolomite karst system. We fi...
Presentation
L’âge de formation des morphologies de la marge cévenole, à l’instar des gorges du Tarn ou de l’Hérault est discutée depuis plus d’un siècle. Cette étude s’inscrit dans cette démarche et, par l’apport de nouvelles contraintes temporelles précise, et parfois questionne, les derniers modèles morphogénétiques. Les datations absolues complétées par l’a...
Article
In this paper, we present the first estimate of the Holocene deformation along the southern front of Gibraltar arc (Morocco) and the first field constraints on the local 1755 CE Fes-Meknes surface rupturing earthquake which could be associated to the “Great Lisbon Earthquake” (M > 8.5) in November 1st, 1755. Using satellite imagery, aerial photogra...
Article
Full-text available
In this study we attempt to evaluate the magnitude of epikarstic water storage variation in various karst settings using a relative spring gravimeter. Gravity measurements are performed two times a year at the surface and inside caves at different depths on three karst aquifers in southern France: two limestone karst systems and one dolomite karst...
Conference Paper
Full-text available
Although subject to significant earthquakes, the region covering theWestern Alps and Pyrenees in southern France, northern Spain, and northern Italy is characterized by very slow deformation rates (below 1 mm a-1), leading to ongoing debates regarding the driving processes and characteristics of this seismicity. We present a new 3-D velocity field...
Conference Paper
Full-text available
In this study we present an up-to-date velocity field of Iran, including the largest number of data ever presented on this region. It includes both a synthesis of all previously published campaign data (Raeesi et al., 2016) and all data from the Iranian Permanent GNSS Network (IPGN). The IPGN data cover some parts of Iran which were previously scar...
Conference Paper
Full-text available
On the southern margin of the Western Mediterranean sea, the Moroccan Rif Cordillera is a thin-skinned fold and thrust belt resulting from the NW-SE convergence between the African and Eurasian lithospheric plates. At the present-day, the kinematics of the western and southern borders of the Rif are characterized by active thrusting consistent with...
Article
Although the first-order pattern of present-day deformation is relatively well resolved across the Himalayas, irregular data coverage limits detailed analyses of spatial variations of interseismic coupling. We provide the first GPS velocity field for the Bhutan Himalaya. Combined with published data, these observations show strong East - West varia...
Poster
Full-text available
The quantification of interseismic coupling along the Himalayan arc is a primary question to address the seismic hazard. How much of the strain is accommodated along the fault during earthquake or elastically during the interseismic period is a key question to characterize the deficit accumulation along the Himalayan arc. From the GPS data acquired...
Article
Full-text available
We present a new 3-D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees, and southern France. The velocity field is based on a Precise Point Positioning (PPP) solution, to which we apply a common-mode filter, defined by the 26 longest time series, in order to correct for network-wide biases (reference frame,...
Article
Full-text available
We present a new 3D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees, and southern France. The velocity field is based on a Precise Point Positioning (PPP) solution, to which we apply a common-mode filter, defined by the 26 longest time series, in order to correct for network-wide biases (reference frame, e...
Article
Full-text available
Collisional mountain belts grow as a consequence of continental plate convergence and eventually disappear under the combined effects of gravitational collapse and erosion. Using a decade of GPS data, we show that the western Alps are currently characterized by zero horizontal velocity boundary conditions, offering the opportunity to investigate or...
Article
More than 10 years of geodetic measurements demonstrate an uplift rate of 1-3 mm/yr of the high topography region of the Western Alps. By contrast, no significant horizontal motion has been detected. Two uplift mechanisms have been proposed: (1) the isostatic response to denudation, responsible for only a fraction of the observed uplift and, (2) th...
Article
Normal faulting mechanisms observed in the northern foothills of the Central-Western Pyrenees are remarkable since one expects thrust faults at a convergent plate boundary. To understand the mechanisms involved, we used numerical modeling and investigated the impact of the following processes: 1) Gravitational Potential Energy associated with topog...
Article
Full-text available
The Pyrenean mountain range is a slowly deforming belt with continuous and moderate seismic activity. To quantify its deformation field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995–1997,...
Conference Paper
Full-text available
Les Pyrénées sont une chaîne de montagne à déformation lente avec une activité sismique continue et modérée. Afin de quantifier la déformation horizontale actuelle, nous présentons un champ de vitesses estimé à partir de mesures GPS couvrant une période de 18 ans. Le réseau PotSis installé en 1992, et le réseau ResPyr installé en deux phases en 199...
Poster
Rivers incision results from the interaction of vertical surface displacement (uplift, tectonic), climate, and base-level lowering. Recent numerical modelling shows that erosion-induced isostatic rebound triggers uplift and extension in low convergent mountain, such as Alps and Pyrenees. Quantify valley incision is a proxy of erosion rate and can b...
Article
Full-text available
The Pyrenean mountain range is a slowly deforming belt with continuous and moderate seismic activity. To quantify its deformation field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995–1997,...
Article
Full-text available
GPS data reveal that the Brahmaputra Valley has broken from the Indian plate and rotates clockwise relative to India about a point a few hundred km west of the Shillong plateau The GPS velocity vectors define two distinct blocks separated by the Kopili fault upon which 2–3 mm/yr of dextral slip is observed: the Shillong block between longitudes 89-...
Conference Paper
Full-text available
We present results of a geomorphological and morphotectonic analysis of the Rif Mountains (Morocco). We show that the present day kinematics of the Rif is characterized by active deformation along normal and left-lateral strike-slip faults in the NorthEast (Trougout, Rouadi, Boujibar and Nekor faults), reverse fault in the South (the South Rif Fron...
Conference Paper
Full-text available
The Southern Rif Front (SRF) is located at the southernmost frontal part of the Rif Cordillera (Morocco) and overthrusts the foreland basins of Saiss and Gharb. Extending over a length of ∼150km between Fez, Meknes and Rabat cities, the SRF stands out as a major active structure. It represents an important seismic hazard for these highly-populated...
Conference Paper
Full-text available
Very high resolution digital elevation models are a key component of modern quantitative geomorphology. In parallel to high-precision but time-consuming kinematic GPS and/or total station surveys and dense coverage but expensive LiDAR campaigns, we explore the usability of affordable, flexible, wide coverage digital surface models (DSMs) derived fr...
Presentation
Full-text available
Extending over a length of ~150km and located close to the cities of Fez, Meknes and Rabat, the Southern Rif Front (SRF) stands out as a major active structure of the Rif Cordillera (Morocco). It represents an important seismic hazard for these highly populated cities of the region as evidenced by the historical seismic activity. The last historica...
Article
Full-text available
Surface displacements due to temporal changes in environmental mass redistributions are observable in the coordinate time series of many Global Navigation Satellite System (GNSS) sites. In this study, we investigated the effect of loading on estimates of tectonic velocity computed from campaign-style GNSS observations. The study region is in the Py...
Article
Full-text available
estimates of the geodetic and geologic slip rates of the 1500 km long Altyn Tagh fault bordering the northern edge of the Tibetan plateau vary by a factor of five. Proposed reasons for these discrepancies include poor GPS geometry, interpretative errors in terrace morphology, and changes in fault slip rate over time. Here we present results from a...
Poster
Abstract / Discussion Poster RESIF (Octobre 2013) Fifteen years of GPS measurements in France have led to unexpected results : - horizontal deformation is very low (<0.5 mm/year) like in an intracontinal domain. - uplift in the Alps can reach 1 to 2 mm/year(1). Despite their low tectonic activity, mountain belts of Western Europe exhibit seismogeni...
Article
Full-text available
Iran is an active continental domain accommodating the convergence between the Arabia and Eurasia plates. In northwestern Iran, deformation between the Central Iranian block and the Caucasus domain is mainly accommodated by right lateral strike-slip on the Tabriz fault. Cities and villages, including the city of Tabriz, have been destroyed by sever...
Conference Paper
Full-text available
We present results of a geomorphological and morphotectectonic analysis of the Rif. Our study area encompasses a region running from the eastern border of the Rif up to the Atlantic coast to the west, and including the southwestern foreland of the range. We show that the present day kinematics of the Rif is characterized by active deformations alon...
Article
Mechanisms that control seismic activity in low strain rate areas such as western Europe remain poorly understood. For example, in spite of low shortening rates of <0.5 mm/yr, the Western Alps and the Pyrenees are underlain by moderate but frequent seismicity detectable by instruments. Beneath the elevated part of these mountain ranges, analysis of...
Article
We present the 1998–2009 GPS-derived velocity field for the Armenia region based on a survey-mode observation network of 31 GPS sites. We combine our results with previous GPS studies of the region to better assess the deformation of the Lesser Caucasus and Kura basin region. The results show that the Kura basin and the Lesser Caucasus regions are...
Conference Paper
Compared to Nepal, seismogenic potential of Bhutan remains enigmatic due to its low present-day seismicity rate. Over the last three centuries, the only large reported event in this area is a Mw=8.1 earthquake in 1897 that occurred further south of the Main Himalayan Thrust (MHT) near the Shillong Plateau. New insights from a GPS network in Bhutan...