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Erwan ROUSSEL

Ingénieur de recherche

Contact : erwan.roussel@uca.fr

Tel : 33 + (0)4 73 34 68 43


Thèmes de recherche

- Ajustements glaciaires et fluvioglaciaires & Changement global / Glacial and fluvial adjustments to global change
- Réponses complexes des systèmes géomorphologiques / Complex response of geomorphological systems
- Dégradation du patrimoine bâti / Stone decay & Cultural heritage
- Recherches et veilles méthodologiques (Photogrammétrie, LiDAR, SIG, analyse d’image, télédétection, modélisation 3D, statistique, géostatistique). / Methodological research (Photogrammetry, LiDAR, GIS, 3D modelisation, image analyses, geostatistic)

Terrains de recherche

- Massif central
- Alpes
- Islande


PUBLICATIONS

ACL - Articles dans des revues à comité de lecture

2017


  • TOUMAZET Jean-Pierre, Vautier Franck, Roussel Erwan et Dousteyssier Bertrand« Automatic detection of complex archaeological grazing structures using airborne laser scanning data », Journal of Archaeological Science: Reports, 12, p. 569-579. DOI : 10.1016/j.jasrep.2017.03.012. https://hal.archives-ouvertes.fr/hal-01627607.
    Résumé : The use of Light Detection And Ranging (LiDAR) for archaeological purposes is becoming more prevalent in order to detect and to document remains located in forested areas. One of the main interests of airborne laser scanning is to put the archaeological information in their context, and to allow a better understanding of the relation between each item and its environment. This concept of archaeological landscape generally results in a too large amount of data to permit a manual analysis. This paper describes an approach for the automatic detection of elementary archaeological grazing structures, found in high concentration in some places of Auvergne (France). These elementary structures are generally connected, creating complex archaeological grazing sets. The detection process is based on the design of a model of an elementary grazing structure. The automatic detection is then carried out, based on the evaluation of the matching degree of each element with the model and on their belonging to complex archaeological grazing structures. The efficiency of the method is tested, by comparison with the manual digitalisation of an expert, on a restricted zone, and the results show that the success rate of the automatic detection reaches higher values than classical template matching approaches. The additional criterion, based on the belonging of each elementary structure to a more complex one, improves the detection success: In a complementary way, this approach offers new opportunities: it is also possible to detect complex structures with a template matching approach, if they contain some simple forms, that can be modelled.
    Mots-clés : Archaeological structures, Digital terrain model DTM, Geoarcheology, LIDAR, Local relief model.
2016


  • Chenet Marie, Brunstein Daniel, Jomelli Vincent, Roussel Erwan, Rinterknecht Vincent, Mokadem Fatima, Biette Melody, Robert Vincent et Léanni Laëtitia« 10Be cosmic-ray exposure dating of moraines and rock avalanches in the Upper Romanche valley (French Alps): Evidence of two glacial advances during the Late Glacial/Holocene transition », Quaternary Science Reviews, 148, p. 209 - 221. DOI : 10.1016/j.quascirev.2016.07.025. https://hal.archives-ouvertes.fr/hal-01480986.
    Mots-clés : 10Be cosmic-ray exposure dating, French Alps, Glacier fluctuations, Holocene, Late Glacial.


  • Corenblit Dov Jean-François, Steiger Johannes, Charrier Gaspard, Darrozes José, Garófano-Gómez Virginia, Garreau Alexandre, González Eduardo, Gurnell Angela M., Hortobágyi Borbála, Julien Frédéric, Lambs Luc, Larrue Sébastien, Otto Thierry, Roussel Erwan, Vautier Franck et Voldoire Olivier« Populus nigra L. establishment and fluvial landform construction: biogeomorphic dynamics within a channelized river », Earth Surface Processes and Landforms, 41, p. 1276–1292. DOI : 10.1002/esp.3954. https://hal.archives-ouvertes.fr/hal-01381848.
    Résumé : Populations of the riparian pioneer species Populus nigra L. which establish on alluvial bars within river channels modulate sediment dynamics and fluvial landforms. Dense cohorts of P. nigra have colonized gravel point bars along the channelized River Garonne, France, during the last 20 years and have enhanced the vertical, lateral and longitudinal development of the bars. For this period, the geomorphic characteristics of two wooded point bars on this laterally stable river are closely linked to the spatial distribution and intensity of establishment and resistance of different cohorts of P. nigra. Furthermore, P. nigra colonization dynamics were controlled by engineer effects of this same species. This relationship is illustrated by a significant correlation between key geomorphic and biological variables measured in situ and characterized with a set of four aerial photographs taken between 2000 and 2010. The development of wooded point bars, which are discrete biogeomorphic units, over the studied period, appear to result from a specific biogeomorphic positive feedback of matter aggregation and vegetation establishment related to sediment trapping and stabilization by pioneer engineer plants.We propose a conceptual model of biogeomorphic unit construction for channelized, lateral stable rivers.We consider the resultant biogeomorphic units as functional from an ecological point of view because P. nigra enhances at the cohort scale (i) its own inherent capacity to resist hydrogeomorphic disturbances, and (ii) its resilience capacity as a result of successful colonization, especially downstream of mature poplar stands.
    Mots-clés : black poplar, fluvial landform, vegetation establishment.


  • Corenblit Dov Jean-François, Vidal Vincent, Cabanis Manon, Steiger Johannes, Garófano-Gómez Virginia, Garreau Alexandre, Hortobágyi Borbála, Otto Thierry, Roussel Erwan et Voldoire Olivier« Seed retention by pioneer trees enhances plant diversity resilience on gravel bars: Observations from the river Allier, France », Advances in Water Resources, 93, p. 182–192. DOI : 10.1016/j.advwatres.2016.02.015. https://hal.archives-ouvertes.fr/hal-01381840.
    Résumé : Pioneer riparian trees which establish in river active tracts on gravel bars enhance fine sediment reten- tion during high flows within their stands and in their lee side, forming obstacle marks. Fine sediment retention can be accompanied by deposition of seeds transported by water dispersal, i.e. by hydrochory. We tested the hypothesis that pioneer riparian trees significantly control seed deposition on gravel bars by forming sediment obstacle marks. We described the seed bank structure and compared samples col- lected from obstacle marks and bare coarse-grained bar surfaces. At the surface (at 2 cm depth), seed abundance ( N ) and richness ( S ) (expressed as mean ±sd) were significantly higher in areas directly af- fected by riparian trees, i.e. obstacle marks, ( N : 693 ±391; S : 17 ±3) than in bare surfaces ( N : 334 ±371; S : 13 ±5). Surface and sub-surface (at 20 cm depth) samples were also significantly different, with the sub-surface samples almost devoid of seeds (respectively N : 514 ±413; S : 15 ±5 and N : 3 ±6; S : 1 ±2). These results suggest a biogeomorphic feedback between sediment and associated seed retention medi- ated by hydrochory, vegetation growth and local seed dispersal mediated by barochory. Such feedback may improve plant diversity resilience on gravel alluvial bars of high-energy rivers.
    Mots-clés : Facilitation, Pioneer riparian species, Sediment tails, Seed bank.


  • Hortobágyi Borbála, Corenblit Dov Jean-François, Vautier Franck, Steiger Johannes, Roussel Erwan, Burkart Andreas et Peiry Jean-Luc« A multi-scale approach of fluvial biogeomorphic dynamics using photogrammetry », Journal of Environmental Management. DOI : 10.1016/j.jenvman.2016.08.069. https://hal.archives-ouvertes.fr/hal-01426679.
    Résumé : Over the last twenty years, significant technical advances turned photogrammetry into a relevant tool for the integrated analysis of biogeomorphic cross-scale interactions within vegetated fluvial corridors, which will largely contribute to the development and improvement of self-sustainable river restoration efforts. Here, we propose a cost-effective, easily reproducible approach based on stereophotogrammetry and Structure from Motion (SfM) technique to study feedbacks between fluvial geomorphology and riparian vegetation at different nested spatiotemporal scales. We combined different photogrammetric methods and thus were able to investigate biogeomorphic feedbacks at all three spatial scales (i.e., corridor, alluvial bar and micro-site) and at three different temporal scales, i.e., present, recent past and long term evolution on a diversified riparian landscape mosaic. We evaluate the performance and the limits of photogrammetric methods by targeting a set of fundamental parameters necessary to study biogeomorphic feedbacks at each of the three nested spatial scales and, when possible, propose appropriate solutions. The RMSE varies between 0.01 and 2 m depending on spatial scale and photogrammetric methods. Despite some remaining difficulties to properly apply them with current technologies under all circumstances in fluvial biogeomorphic studies, e.g. the detection of vegetation density or landform topography under a dense vegetation canopy, we suggest that photogrammetry is a promising instrument for the quantification of biogeomorphic feedbacks at nested spatial scales within river systems and for developing appropriate river management tools and strategies.
    Mots-clés : Fluvial biogeomorphologic feedbacks, Fluvial landforms, Multi-scale analysis, Riparian vegetation, Stereophotogrammetry, Structure from motion.


  • Roussel Erwan, Toumazet Jean-Pierre, Marren Philip M. et Cossart Etienne« Iceberg jam floods in Icelandic proglacial rivers: testing the self-organized criticality hypothesis », Géomorphologie : relief, processus, environnement, vol. 22 – 1/2016, p. 37-49. DOI : 10.4000/geomorphologie.11229. http://geomorphologie.revues.org/11229.


  • Roussel Erwan, Toumazet Jean-Pierre, Marren Philip M. et Cossart Etienne« Iceberg jam floods in Icelandic proglacial rivers: testing the self-organized criticality hypothesis », Géomorphologie : relief, processus, environnement, 22 (1), p. 37 - 49. DOI : 10.4000/geomorphologie.11229. https://hal.archives-ouvertes.fr/hal-01598104.

  • Roussel Erwan, TOUMAZET Jean-Pierre, Marren Philip M. et Cossart Etienne« Iceberg jam floods in Icelandic proglacial rivers: testing the self-organized criticality hypothesis », Géomorphologie: …. https://hal.archives-ouvertes.fr/hal-01627598.


  • Roussel Erwan, Toumazet Jean-Pierre, Philip Marren et Cossart Etienne« Iceberg jam floods in Icelandic proglacial rivers: testing the self-organized criticality hypothesis », Geomorphologie -Paris-. DOI : 10.4000/geomorphologie.11229. https://hal.archives-ouvertes.fr/hal-01312715.
    Résumé : In this paper, we describe a fluvial marginal process associated with the formation of iceberg jams in Icelandic proglacial lakes. The floods triggered by the release of these iceberg jams have implications for the geomorphic evolution of the proglacial fluvial system. The process of iceberg jam floods share some conceptual characteristics with Self-Organized Criticality (SOC) approach of complex systems. Using a simple numerical model and field observations, we test the hypothesis that iceberg jam floods exhibit SOC. Field observations and aerial photo-interpretations in southeastern Iceland demonstrate the occurrence of icebergs jam in ice-contact lakes. The mapping of the south Vatnajökull margins between 2003 and 2012 reveals an increase of the calving potentiality and a rise in the likelihood of iceberg jam flood occurrence. Based on the results of the numerical model and field observations, we suggest that iceberg jam floods should be recognized as a SOC phenomenon. Analysis of the simulated time-series show that the iceberg jam floods become less frequent and more similar in magnitude over time. This global trend is related to the gradual enlargement of the lake outlet channel.
    Mots-clés : iceberg jam floods, Iceland, proglacial lakes, proglacial rivers, self-organized criticality.


  • Roussel Erwan, Toumazet Jean-Pierre, Philip Marren et Cossart Etienne« Iceberg jam floods in Icelandic proglacial rivers: testing the self-organized criticality hypothesis », Géomorphologie : relief, processus, environnement. DOI : 10.4000/geomorphologie.11229. https://hal.archives-ouvertes.fr/hal-01312715.
    Résumé : In this paper, we describe a fluvial marginal process associated with the formation of iceberg jams in Icelandic proglacial lakes. The floods triggered by the release of these iceberg jams have implications for the geomorphic evolution of the proglacial fluvial system. The process of iceberg jam floods share some conceptual characteristics with Self-Organized Criticality (SOC) approach of complex systems. Using a simple numerical model and field observations, we test the hypothesis that iceberg jam floods exhibit SOC. Field observations and aerial photo-interpretations in southeastern Iceland demonstrate the occurrence of icebergs jam in ice-contact lakes. The mapping of the south Vatnajökull margins between 2003 and 2012 reveals an increase of the calving potentiality and a rise in the likelihood of iceberg jam flood occurrence. Based on the results of the numerical model and field observations, we suggest that iceberg jam floods should be recognized as a SOC phenomenon. Analysis of the simulated time-series show that the iceberg jam floods become less frequent and more similar in magnitude over time. This global trend is related to the gradual enlargement of the lake outlet channel.
    Mots-clés : iceberg jam floods, Iceland, proglacial lakes, proglacial rivers, self-organized criticality.
2014

  • André Marie-Françoise, Vautier Franck, Voldoire Olivier et Roussel Erwan« Accelerated stone deterioration induced by forest clearance around the Angkor temples », Science of the Total Environment, 493, p. 98-108. https://hal.archives-ouvertes.fr/hal-01115192.
    Mots-clés : cultural heritage, geomorphology and weathering.


  • Corenblit Dov, Steiger Johannes, González E., Gurnell A. M., Charrier G., Darrozes J., Dousseau J., Julien F., Lambs L., Larrue Sébastien, Roussel Erwan, Vautier Franck et Voldoire Olivier« The biogeomorphological life cycle of riparian poplar during the fluvial biogeomorphological succession: a special focus on Populus nigra L. », Earth Surface Processes and Landforms, 39 (4), p. 546–563. DOI : 10.1002/esp.3515. https://hal.archives-ouvertes.fr/hal-01059244.
    Résumé : Riverine ecosystems are recurrently rejuvenated during destructive flood events and vegetation succession starts again. Poplars (i.e. species from Populus genera) respond to hydrogeomorphological constraints, but, in turn, also influence these processes. Thus, poplar development on bare mineral substrates is not exclusively a one-way vegetative process. Reciprocal interactions and adjustments between poplar species and sediment dynamics during their life cycle lead to the emergence of biogeomorphological entities within the fluvial corridor, such as vegetated islands, benches and floodplains. Based on a review of geomorphological, biological and ecological literature, we have identified and described the co-constructing processes between riparian poplars and their fluvial environment. We have explored the possibility that the modification of the hydrogeomorphological environment exerted, in particular, by the European black poplar (Populus nigra L.), increases its fitness and thus results in positive niche construction. We focus on the fundamental phases of dispersal, recruitment and establishment until sexual maturity of P. nigra by describing the hierarchy of interactions and the pattern of feedbacks between biotic and abiotic components. We explicitly relate the biological life cycle of P. nigra to the fluvial biogeomorphic succession model by referring to the ‘biogeomorphological life cycle’ of P. nigra. Finally, we propose new research perspectives based on this theoretical framework. Copyright © 2014 John Wiley & Sons, Ltd.
    Mots-clés : abiotic-biotic feedback, biogeomorphological life cycle, engineer species, evolutionary geomorphology, fluvial biogeomorphic succession model, Salicaceae.
2013


  • Roussel Erwan et André Marie-Françoise« Quantitative assessment of pre- and post-restoration weathering rates of limestone Mayan temples (Uxmal, Yucatán) », Geografia Fisica e Dinamica Quaternaria, 36, p. 169-179. DOI : 10.4461/GFDQ.2013.36.14. https://hal.archives-ouvertes.fr/hal-00987405.
    Résumé : The House of Turtles is one of the Mayan buildings of the Uxmal site in Yucatan. It has been erected during the Terminal Classic Period (AD 890-915), abandoned around AD 1050, and restored between 1969 and 1972. This monument was selected to quantitatively assess the impact of contemporary restoration practices on limestone weathering. Based on archival research and multi-scale photogrammetric surveys, weathering rates were calculated for two periods, covering respectively almost 1000 years (1050-2012) and 50 years (1972-2012). Whatever the spatial scale, whatever the construction choice, post-restoration weathering rates are systematically faster than long-term rates: at the scale of the whole façade, stone recession has operated 38 times faster since restoration than on non-restored historical parts of the building (7.6 mm instead of 0.2 mm per century). This general trend is ascribed to the removal of the stucco coating that has protected limestone and delayed deterioration from the Mayan building times until the contemporary clearing and restoration operations. Another factor responsible for accelerated limestone decay is the replacement of wooden lintels by cement lintels, as indicated by the spatial distribution of deterioration hotspots on the façade and by the computed weathering rates obtained for six fine-scale windows taking into account the construction/restoration choices. This quantitative assessment leads to emphasise the need for softer, less intrusive restoration practices and conservation strategies, that should restrict the use of incompatible materials like cement and reinforced concrete, and consider stucco as a protective skin worth being maintained.
    Mots-clés : Conservation strategies, cultural heritage, Decay assessment, Limestone, Maya architecture, rock weathering, Yucatán.
2012
2011


  • Chenet Marie, Roussel Erwan, Jomelli Vincent, Grancher Delphine et Cooley Daniel« A response to the commentary of M. Dąbski about the paper ‛Asynchronous Little Ice Age glacial maximum extent in southeast Iceland’ (Geomorphology (2010), 114, 253–260) », Geomorphology, 128 (1-2), p. 103-104. DOI : 10.1016/j.geomorph.2010.12.024. http://linkinghub.elsevier.com/retrieve/pii/S0169555X10005684.
    Résumé : In a commentary about the paper ‛Asynchronous Little Ice Age glacial maximum extent in southeast Iceland’ (Geomorphology 114 (2010) 253-260), M. Dąbski questioned the validity of the generalized extreme value method and the Bayesian approach in lichenometric dating of the outermost LIA Fláajökull moraines in SE Iceland. This paper responds to these criticisms by explaining the relevance of the method applied and the relevance of the dates obtained.
    Mots-clés : Bayesian approach, Fláajökull, GEV method, Iceland, Lichenometry.
2010

  • Chenet Marie, Roussel Erwan, Jomelli Vincent et Grancher Delphine« Asynchronous Little Ice Age glacial maximum extent in southeast Iceland », Geomorphology, 114 (3), p. 253-260. https://hal.archives-ouvertes.fr/hal-00449570.
    Résumé : The Little Ice Age (LIA) maximum glacial extent of 13 glaciers located in SE Iceland was dated by lichenometry to check for intraregional variations. Different lichenometric approaches were applied to date maximum LIA moraines, and they all showed high variability between glaciers. According to the Extreme Value Theory and Bayesian approach, LIA advances in the region occurred in or around A.D. 1740–1760, A.D. 1810–1820 and A.D. 1840–1880 with confidence intervals of between 8 and 21 years. The dates were correlated with geomorphic characteristics of glacier tongues: hypsometric and slope parameters can be considered as determining factors in the variability of glacier timing during the LIA, as previously observed in Norway and in the Alps. In terms of timing, results obtained in SE Iceland were similar to those obtained for other glacier regions around the North Atlantic.
    Mots-clés : dating, Glacier, Iceland, Lichenometry, Little Ice Age.

C-ACT - Communications avec publication dans des actes

2016
2015
2014

  • Florez Marta, Dousteyssier Bertrand, Vautier Franck, Roussel Erwan et TOUMAZET Jean-Pierre« Nouvelles données sur le pastoralisme à l'époque moderne dans la chaîne des Puys (Massif Central, France) », in Journée d'études “ Les espaces pastoraux : usages et enjeux environnementaux ”., Aix en Provence, France : Communication orale. https://hal.archives-ouvertes.fr/hal-01628166.
  • Florez Marta, Dousteyssier Bertrand, Vautier Franck, Roussel Erwan, Toumazet Jean-Pierre, Faure Marlène et Abadi Mohamed« Archaeomophological approaches and LIDAR data analysis to study a hidden mid-mountain cultural Landscape. The study case of Puy de Dôme (France) » (présenté à September 17th-20th 2014, 3rd International landscape archaeology conference, LAC 2014), in Communication orale, Rome, Italie.
    Résumé : In the last decade, the use of LIDAR data in archaeology has been widespread, providing unexpected results especially in the forested areas. Images obtained by the processing of LIDAR data show the overlay of archaeological structures fossilized in the territory, highlighting the diachronic origin of cultural landscapes. In this context, archaeomorphological approaches can provide theoretical and methodological tools for a diachronic “reading” of human-made landscape forms, and these can be useful for understanding the landscape genesis and its evolution as a social and cultural product. A LIDAR flight undertaken in 2011 in the Chaîne des Puys revealed agro-pastoral structures that had gone unnoticed under the forest protection area of Parc Régional des Volcans d’Auvergne. These facts gave rise to the LIDARCHEO research project (2012-2013), directed by F. Vautier and E. Roussel (Maison des Sciences de l’Homme de Clermont-Ferrand, France), and funded by Clermont Communauté. The project has combined the research of geomorphologists, geographers, archaeologists, historians and specialists in image processing with the aim of developing tools for automatic detection of archaeological structures from LIDAR data. The project allowed us to conduct the first archaeological study of agro-pastoral structures concentrated to the west of the Puy de Dôme. Moreover, it provided further data on buildings in the western sector of the Col de Ceyssat Roman site. Archaeomorphological study has been developed in a GIS database environment including; LIDAR digital terrain models (MDT), local relief models by LIDAR data (LRM), topographical and hydrographical vectorial information, old maps and old cadastral maps. It has also included archaeological surveys, micro-topographic measuring using a total station, archival and documentary research. Archaeomorphological analysis has allowed us to establish different types of agro-pastoral structures that have then been verified by archaeological surveys. Different chronological phases have also been identified between archaeological structures. Finally, morphotypological analysis has been used to develop automatic detection algorithms. This work hitghlights the contribution of archaeomorphological analysis into the study and diachronic interpretation of a mid-mountaincultural landscape from LIDAR data. Furthermore, it illustrates the role of the Archaeomorphology in the development and calibration of tools for automatic detection of archaeological structures from LIDAR data. Thus, Archaeomorphology is a discipline that can offer a wide range of methods and techniques for the study of cultural landscape configuration, as aiding the comprehension and interpretation of associated historical processes.

  • Florez Marta, Dousteyssier Bertrand, Vautier Franck, Roussel Erwan, TOUMAZET Jean-Pierre, Faure Marlène et Abadi Mohamed« Archaeomophological approaches and LIDAR data analysis to study a hidden mid-mountain cultural Landscape. The study case of Puy de Dôme (France) », in 3rd International landscape archaeology conference, Rome, Italy : Communication orale. https://hal.archives-ouvertes.fr/hal-01627649.

  • Peignelin Coline, Defive Emmanuelle, Poiraud Alexandre, Le Coeur Clémence, Virmoux Clément, Vautier Franck, Roussel Erwan, TOUMAZET Jean-Pierre et Gunnell Yanni« Les “ rivières de pierres ” : une formation “ hors classes ” ? Questions posées dans le cas du massif du Mézenc (Velay oriental, Sud-Est du Massif central, France) », in Colloque International Q9, Lyon, France : Communication orale. https://hal.archives-ouvertes.fr/hal-01627637.
  • Peignelin, Defive E., Poiraud A., Le Coeur C., Virmoux C., Vautier F., Roussel Erwan, Toumazet J-P et Gunnel Y« Les « rivières de pierres » : une formation « hors classes » ? Questions posées dans le cas du massif du Mézenc (Velay oriental, Sud-Est du Massif central, France) » (présenté à Colloque International Q9 "le Quaternaire: marqueurs, traceurs et chronomètres"), in Communication orale, 26-28 mars 2014, Lyon, France.
  • Roussel Erwan, Gruzon Soizic, Vautier Franck, Voldoire Olivier et André Marie-Françoise« Using airborne LiDAR in geoarchaeological contexts: Assessment of an automatic tool for the detection and the morphometric analysis of grazing archaeological structures (French Massif Central) » (présenté à European Geosciences Union Meeting), in Poster, April 27-May 2, Vienne, Austria.

  • Roussel Erwan, TOUMAZET Jean-Pierre, Florez Marta, Vautier Franck et Dousteyssier Bertrand« Using airborne LiDAR in geoarchaeological contexts: Assessment of an automatic tool for the detection and the morphometric analysis of grazing archaeological structures (French Massif Central) », in European Geosciences Union, General Assembly, Vienne, Austria : Communication orale. https://hal.archives-ouvertes.fr/hal-01627643.

  • Toumazet Jean-Pierre, Vautier Franck, Roussel Erwan, Florez Marta et Dousteyssier Bertrand« Automatic detection and characteristics extraction of archaeological structures using coupled Geographic Information System software and Scilab » (présenté à 6th International SCILAB users conference SCILABTEC), in Communication orale, May 15-16 2014, Paris, France. https://hal.archives-ouvertes.fr/hal-01112566.
    Résumé : Since the last few years, archaeologists have the opportunity to use a very powerful tool in order to detect archaeological structures located in forest terrain : the airborne LiDAR. A Laser beam, emitted from an airplane, partially goes through the vegetation and is reflected on the ground. A measure of the time necessary for the light signal to return to the source allows then, knowing precisely the position of the transmitter, to reconstruct the relief very accurately. The cost of this tool tends to decrease, and it is now used in almost all the research programs dealing with archaeology when at least a part of the studied area is located under the vegetation. Resorting to the LiDAR yields a huge quantity of data, constituted of clouds made of millions of points from which it is necessary to extract the relevant information. A manual processing of these data is then boring, time consuming, and even sometimes impossible: the automation of the detection process becomes necessary. The presented work deals with the process of automatic detection of archaeological structures. It is applied to former agricultural constructions, built from the medieval to the modern period. They can be found in very high densities in some places in Auvergne. These structures have been chosen to test the process of automatic detection because they are particularly delicate to treat: they are indeed very variable in forms, appearing sometimes isolated, sometimes in group and they are characterised by small relief variations very difficult to detect among the global relief. The process presented uses the associated potentiality of Scilab and a Geographic Information System software. At first, the point cloud is interpolated in order to obtain a Digital Terrain Model (DTM). This DTM is then smoothed, by a moving average filter, in order to erase the abrupt relief variations, generally from anthropogenic origin: the macro relief is then highlighted. It’s then removed from the initial data, so that only the micro relief becomes visible. We thus obtain a Local Relief Model (LRM) in 2D ½.. An algorithm of automatic recognition allows then to detect the structures, to classify them, to extract their geometrical characteristics and to create a database in a totally automated way.
    Mots-clés : Automatic detection, Lidar.

  • Vautier Franck, Roussel Erwan, Toumazet Jean-Pierre, Florez Marta, Faure Marlène, Abadi Mohamed et Dousteyssier Bertrand« Automatic detection of archaeological structures from images derived from clouds of LiDAR points (a methodological research – LiDARCHEO program) » (présenté à TRAIL 2014 : Formation et recherche pour l’interprétation archéologique des données LiDAR), in Communication orale, 26-28 mars 2014, Frasne, France. https://hal.archives-ouvertes.fr/hal-01116185.
    Mots-clés : Automatic detection, Imagery analysis, Lidar.
  • Vautier Franck, Toumazet Jean-Pierre, Roussel Erwan, Faure Marlène, Abadi Mohamed, Florez Marta et Dousteyssier Bertand« Utilisation d’images dérivées d’un jeu de données LIDAR pour la détection automatisée de vestiges archéologiques (programme de recherche méthodologique LiDARCHEO) » (présenté à Journée technique du CRAIG: cartographie et archéologie), in Communication orale, 7 octobre 2014, Clermont-Ferrand, France.

  • Vautier Franck, TOUMAZET Jean-Pierre, Roussel Erwan, Faure Marlène, Abadi Mohamed, Florez Marta et Dousteyssier Bertrand« Utilisation d'images dérivées d'un jeu de données LIDAR pour la détection automatisée de vestiges archéologiques (programme de recherche méthodologique LiDARCHEO) », in Technique du CRAIG: cartographie et archéologie, Clermont-Ferrand, France : Communication orale. https://hal.archives-ouvertes.fr/hal-01628158.

  • Vautier Franck, TOUMAZET Jean-Pierre, Roussel Erwan, Florez Marta, Faure Marlène, Abadi Mohamed et Dousteyssier Bertrand« Automatic detection of archaeological structures from images derived from clouds of LiDAR points (a methodological research – LiDARCHEO program) », in Rencontre internationale TRAIL 2014, Frasne, France : Communication orale. https://hal.archives-ouvertes.fr/hal-01627632.
2013
2012
2011

C-COM - Communications orales dans une conférence nationale ou internationale

2014
2013
  • Roussel Erwan et Chenet Marie« Postglacial rockfalls controls on environmental partitioning of the Haute-Romanche valley (Massif des Écrins, french Alps) » (communication orale), présenté à 8th IAG International Conference on Geomorphology - Paris 2013, Paris.
    Résumé : The Haute-Romanche valley, located in the Massif des Écrins, was widely glaciated during the LGM. Nowadays, the Romanche river is an effluent of two separated glaciers: the Clot des Cavales and the Plate des Agneaux. From the current glaciers fronts to the downstream neoglacial moraines, five successive rockfalls were identified. Their locations are probably linked to preferential areas of postglacial debutressing expression. These large rockfalls produce a semi-permanent environmental partitioning of the valley by controlling sediment flux and fluvial patterns. The objectives of the study are to quantitatively assess the partitioning functions of rockfalls of various volume on the streams long profiles, the downstream fluvial pattern succession and the spatial distribution of archaeological evidences. The topographic surveys of the Haute-Romanche valley floor and rockfalls were done using terrestrial multi-image photogrammetry coupled to a set of DGPS ground control points. The long profiles of the rivers were achieved with DGPS survey. Volumes of rockfalls were estimated by topographic modeling and volumetric computation using GIS software resources. Fluvial pattern analysis and archaeological mapping were completed based on photo-interpretation and field observations. Results show that river channel morphology is highly dependent of rockfall location and volume. Consequently, the downstream river patterns succession is deeply disturbed inducing a long-term segmentation of the fluvial continuum. This longitudinal partitioning of hydro-sedimentary dynamics has potentially major ecological, geoarchaeological and management implications.
2010

C-AFF - Affiches / posters dans une conférence nationale ou internationale

2014

  • Peignelin Coline, Defive Emmanuelle, Poiraud Alexandre, Le Coeur Charles, Virmoux Clément, Vautier Franck, Roussel Erwan, Toumazet Jean-Pierre et Gunnell Yanni« Les " rivières de pierres " : une formation en marge des catégories classiques. Questions posées dans le cas du massif du Mézenc (Velay oriental, Sud-Est du Massif central, France). » (poster), présenté à AFEQ - CNF INQUA. https://hal.archives-ouvertes.fr/hal-01131185.
    Résumé : La province volcanique du Velay oriental (SE du Massif central) compte une forte concentration de pierriers d’origine et d’appellation diverses (éboulis, chirats), issus du démantèlement des affleurements rocheux (rebords de coulées et, surtout, dômes et intrusions phonolitiques). Parmi ces accumulations figurent les « rivières de pierres » ou blockstreams de la littérature anglophone. Il s’agit de langues de blocs métriques redressés en tous sens, sans matrice en surface, déconnectées des amonts pourvoyeurs (gélifraction) et présentes jusque sur des pentes très faibles. Elles ont souvent été assimilées par défaut à d'anciens glaciers rocheux et rattachées sur la base d’arguments morpho-stratigraphiques au Pléniglaciaire supérieur. Elles sont en fait d’origine et d’âge mal connu et ne répondent pas clairement au modèle classique d’un glacier rocheux de haute montagne. Les observations de terrain (caractères intrinsèques, rapports stratigraphiques avec les autres formations, position dans la topographie, distance aux zones-source, contexte structural...), suggèrent des processus de mise en place par fluage et/ou lavage qui restent à préciser, la possibilité d’une chenalisation des blocs par la topographie préexistante (ravines), et posent la question de l’âge, de l’efficacité des processus en jeu et de l’existence éventuelle de plusieurs générations. L’acquisition récente de photographies aériennes traitées en photogrammétrie (orthophotographies, MNT) doit permettre de préciser la description de l’organisation de surface (modelé, fabrique) révélatrice des contraintes liées aux processus de mise en place. D'autre part, les investigations géophysiques menées (GPR et tomographie électrique) pourraient apporter d'intéressants éléments de compréhension. Cette étude s’intègre au programme de recherche WRACC, financé par L’Etablissement Public Loire et le FEDER.
    Mots-clés : Eastern Velay, French Massif Central, Late Glacial, Massif Central Français, Mézenc, Morphologie et processus périglaciaires, Pleistocene.

  • Roussel Erwan, Gruson Soizic, Vautier Franck, Voldoire Olivier et André Marie-Françoise« Assessing spatial trends of cultural stone weathering intensity using a hardness tester: the case of Manglieu Saint-Sébastien church (France) » (poster), présenté à European Geosciences Union Meeting. https://hal.archives-ouvertes.fr/hal-01115999.
    Mots-clés : rock weathering, stone decay.

  • Roussel Erwan, Toumazet Jean-Pierre, Florez Marta, Vautier Franck et Dousteyssier Bertrand« Using airborne LiDAR in geoarchaeological contexts: Assessment of an automatic tool for the detection and the morphometric analysis of grazing archaeological structures (French Massif Central) » (poster), présenté à European Geosciences Union Meeting, 2014. https://hal.archives-ouvertes.fr/hal-01116076.
    Résumé : Airborne laser scanning (ALS) of archaeological regions of interest is nowadays a widely used and established method for accurate topographic and microtopographic survey. The penetration of the vegetation cover by the laser beam allows the reconstruction of reliable digital terrain models (DTM) of forested areas where traditional prospection methods are inefficient, time-consuming and non-exhaustive. The ALS technology provides the opportunity to discover new archaeological features hidden by vegetation and provides a comprehensive survey of cultural heritage sites within their environmental context. However, the post-processing of LiDAR points clouds produces a huge quantity of data in which relevant archaeological features are not easily detectable with common visualizing and analysing tools. Undoubtedly, there is an urgent need for automation of structures detection and morphometric extraction techniques, especially for the "archaeological desert" in densely forested areas. This presentation deals with the development of automatic detection procedures applied to archaeological structures located in the French Massif Central, in the western forested part of the Puy-de-Dôme volcano between 950 and 1100 m a.s.l.. These unknown archaeological sites were discovered by the March 2011 ALS mission and display a high density of subcircular depressions with a corridor access. The spatial organization of these depressions vary from isolated to aggregated or aligned features. Functionally, they appear to be former grazing constructions built from the medieval to the modern period. Similar grazing structures are known in other locations of the French Massif Central (Sancy, Artense, Cézallier) where the ground is vegetation-free.
    Mots-clés : archaeological structures, Automatic tool, Imagery analysis, Lidar, Massif Central France.
2013

  • André Marie-Françoise, Phalip Bruno, Roussel Erwan, Vautier Franck et Voldoire Olivier« Impact of cement repointing on rates of sandstone deterioration in medieval churches of the French Massif Central » (poster), présenté à 8th International Conference on Geomorphology. https://hal.archives-ouvertes.fr/hal-01115997.
    Mots-clés : restoration practices, stone decay.

  • Florez Marta, Dousteyssier Bertrand, Roussel Erwan, Vautier Franck, TOUMAZET Jean-Pierre, Lefeuvre Marion, Miras Yannick et Rieutort Laurent« El fenomeno de las “STRUCTURES EN PEIGNE” en el Macizo Central (Francia). Aportaciones a la caracterzacion de un paisaje cultural de montana » (Poster), présenté à . https://hal.archives-ouvertes.fr/hal-01627620.

  • Lefeuvre Marion, Florez Marta, Miras Yannick, Vautier Franck, Dousteyssier Bertrand, Roussel Erwan et Toumazet Jean-Pierre« Genesis of a cultural landscape : the Chaîne des puys (Massif central, France) » (poster), présenté à MINaH – Managing Inhabited Natural Heritage. https://hal.archives-ouvertes.fr/hal-01112302.

  • Lefeuvre Marion, Florez Marta, Miras Yannick, Vautier Franck, Dousteyssier Bertrand, Roussel Erwan et TOUMAZET Jean-Pierre« Genesis of a cultural landscape : the Chaîne des puys (Massif central, France) » (Poster), présenté à . https://hal.archives-ouvertes.fr/hal-01627629.

  • Roussel Erwan et Chenet Marie« Postglacial rockfalls controls on environmental partitioning of the Haute-Romanche valley (Massif des Écrins, french Alps) » (poster), présenté à 8th International Conference on Geomorphology. https://hal.archives-ouvertes.fr/hal-01116101.
    Résumé : The Haute-Romanche valley, located in the Massif des Écrins, was widely glaciated during the LGM. Nowadays, the Romanche river is an effluent of two separated glaciers: the Clot des Cavales and the Plate des Agneaux. From the current glaciers fronts to the downstream neoglacial moraines, five successive rockfalls were identified. Their locations are probably linked to preferential areas of postglacial debutressing expression. These large rockfalls produce a semi-permanent environmental partitioning of the valley by controlling sediment flux and fluvial patterns. The objectives of the study are to quantitatively assess the partitioning functions of rockfalls of various volume on the streams long profiles, the downstream fluvial pattern succession and the spatial distribution of archaeological evidences. The topographic surveys of the Haute-Romanche valley floor and rockfalls were done using terrestrial multi-image photogrammetry coupled to a set of DGPS ground control points. The long profiles of the rivers were achieved with DGPS survey. Volumes of rockfalls were estimated by topographic modeling and volumetric computation using GIS software resources. Fluvial pattern analysis and archaeological mapping were completed based on photo-interpretation and field observations. Results show that river channel morphology is highly dependent of rockfall location and volume. Consequently, the downstream river patterns succession is deeply disturbed inducing a long-term segmentation of the fluvial continuum. This longitudinal partitioning of hydro-sedimentary dynamics has potentially major ecological, geoarchaeological and management implications.
    Mots-clés : Deglaciation, French Alps, proglacial rivers, rockfall.
2011

TH - Thèses

2011

  • Roussel Erwan« Réponses des glaciers et des sandurs sud-islandais au réchauffement climatique post-petit âge glaciaire : Modalités et rythmes d'ajustement du continuum glacio-fluvial », Theses, Université Blaise Pascal - Clermont-Ferrand II. https://tel.archives-ouvertes.fr/tel-00705325.
    Mots-clés : Dynamiques glaciaires et fluvioglaciaires, Geomorphic impacts of post-LIA climate change, Glacial and fluvioglacial dynamics, Iceland, Impacts géomorphologiques du changement climatique post-PAG, Islande.

AP - Autres publications

2013
2011
2010

  • André Marie-Françoise, Phalip Bruno, Voldoire Olivier, Vautier Franck et Roussel ErwanLa détérioration des motifs sculptés dans trois grès d’Angkor : influence des facteurs géologiques et environnementaux, Research Report, UNESCO - Comité International de Coordination pour la Sauvegarde et le développement du Site Historique d’Angkor, 19ème Session Technique, 4 p. p. https://hal.archives-ouvertes.fr/hal-01116065.
    Mots-clés : Angkor temples, geomorphology and weathering, stone decay.
  • André Marie-Françoise, Vautier Franck, Voldoire Olivier, Etienne Samuel, Mercier Denis, Corenblit Dov, Phalip Bruno et Roussel ErwanLe temple de Ta Keo : contribution au diagnostic de détérioration des parements sculptés et à la définition des futures stratégies de conservation et de valorisation, Rapport d’étape UNESCO. (17ème session plénière du Comité International de Coordination pour la Sauvegarde et le Développement du Site d’Angkor).