Nicolas Villeneuve

University of La Réunion · Géographie

Effective and rapid effusive crisis response is necessary to mitigate the risks associated with lava flows that could threaten or inundate inhabited or visited areas. At Piton de la Fournaise (La Réunion, France), well-established protocols between Observatoire Volcanologique du Piton de la Fournaise - Institut de Physique du Globe de Paris (OVPF-I...

Since 1979, Piton de la Fournaise (La Réunion) has erupted on average two times per year, with 95 % of these eruptions occurring within an uninhabited caldera. However, lava flows have occasionally impacted populated regions on the island, as in 1977 and 1986. Since 2014, an integrated satellite data–driven multinational response to effusive crises...

Forest destruction by ‘a‘ā lava flow is common. However, mechanical and thermal interactions between the invading lava and the invaded forest are poorly constrained. We complete mapping, thermal image and sample analyses of a channel-fed ‘a‘ā lava flow system that invaded forest on the NE flank of Mt. Etna (Italy) in 2002. These lava flows destroye...

Formalised elicitation of expert judgements has been used to help tackle several problematic societal issues, including volcanic crises and pandemic threats. We present an expert elicitation exercise for Piton de la Fournaise volcano, La Réunion island, held remotely in April 2021. This involved 28 experts from nine countries who considered a hypot...

Le Piton des Neiges est l’ancien volcan de l’Ile de La Réunion. Il est caractérisé par la présence de trois cirques (Cilaos, Mafate, Salazie), qui sont de larges dépressions en entonnoir évasé vers l’amont entaillant profondément l’édifice. Ces cirques ont été successivement interprétés comme d’anciennes calderas, comme des cicatrices de glissement...

Piton de la Fournaise, situated on La Réunion island (France), is one of the most active hot spot basaltic shield volcanoes worldwide, experiencing at least two eruptions per year since the establishment of the volcanological observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % of some ∼ 250 histo...

The reconstruction of volcanic landforms is an effective way to assess the construction history and growth rates of volcanic structures and is a useful tool to estimate erosion rates. We propose a simple geometrical approach to reveal the location of the long-term eruption centers and the general shape of eroded volcanoes within the altitudinal ran...

In four study areas within different lithological settings and rockfall activity, lidar data were applied for a morphometric analysis of block sizes, block shapes and talus cone characteristics. This information was used to investigate the dependencies between block size, block shape and lithology on the one hand and runout distances on the other h...

The geomorphology of hot spot volcanism and specifically oceanic hot spot volcanism is best explained and understood by examining volcanic edifices development above hot spots using nested scales. This includes starting from a large overview to progressively more and more detailed scales. The construction of hot spot volcanic chains and the identif...

Le volcan du Piton de la Fournaise, avec plus d'une éruption par an depuis l'installation de homme sur l'île de La Réunion, est un des volcans les plus actifs au monde. Il est également, un des plus surveillés et des plus densément instrumentés. C'est un objet de recherche scientifique très attractif où des méthodes sont parfois développées et test...

Piton de la Fournaise, situated on La Réunion Island (France), is one of the most active hot spot basaltic shield volcanoes worldwide, experiencing at least two eruptions per year since the establishment of the observatory in 1979. Eruptions are typically fissure-fed and form extensive lava flow fields. About 95 % of some ~250 historical events (si...

In March 2020, the coronavirus disease 2019 outbreak was declared a pandemic by the World Health Organization and became a global health crisis. Authorities worldwide implemented lockdowns to restrict travel and social exchanges in a global effort to counter the pandemic. In France, and in French overseas departments, the lockdown was effective fro...

In high mountain regions, rockfalls are common processes, which transport different volumes of material and therefore endanger populated areas and infrastructure facilities. In four study areas within different lithological settings, LiDAR (light detection and ranging) data were acquired for a morphometric analysis of block sizes, block shapes and...

Cirques" are funnel-shaped, seaward-narrowing valleys commonly observed on many volcanic islands worldwide, such as Tahiti (French Polynesia), La Palma or Gran Canaria (Canary), Anjouan (Comores), and Maui or Molokai (Hawai'i). Because they contradict the basics of regressive erosion by rivers, these geomorphic structures have been interpreted in m...

We produced new multi-temporal Digital Elevation Models (DEMs) of the April 2007 summit collapse at Piton de la Fournaise from previously unused aerial photographs. This dataset revealed the precise temporal evolution of collapsed volume and caldera morphological changes. Four days after the onset of an eruption at an unusually low elevation, the s...

Understanding the thermo-rheological regime and physical character of lava while it is flowing is crucial if we are to adequately model lava flow emplacement dynamics. We present measurements from simultaneous sampling and thermal imaging across the full width of an active channel at Piton de la Fournaise (La Réunion, France). Our data set involves...

This file contains the reports automatically generated within Agisoft Photoscan Pro software, for the photogrammetric reconstructions of the surface of the Enclos Fouqué area on Piton de la Fournaise Volcano, La Réunion, between 1950 and 2003, during the course of the PhD work of Allan Derrien at the Observatoire Volcanologique du Piton de la Fourn...

This file contains the reports automatically generated within Agisoft Photoscan Pro software, for the photogrammetric reconstructions of the surface of the Cratère Dolomieu area on Piton de la Fournaise Volcano, La Réunion, between 2007 and 2019, during the course of the PhD work of Allan Derrien at the Observatoire Volcanologique du Piton de la Fo...

This file contains the reports automatically generated within Agisoft Photoscan Pro software, for the photogrammetric reconstructions of the surface of new lava flows area on Piton de la Fournaise Volcano, La Réunion, between 2008 and 2018, during the course of the PhD work of Allan Derrien at the Observatoire Volcanologique du Piton de la Fournais...

La Réunion Island, located in the western Indian Ocean, undergoes heavy annual precipitations during the rainy season (December to April) and particularly during tropical storms and cyclones. Heavy rainfalls that affect this volcanic island modify the stream dynamic and control the sediment transport and the very active erosion. However, in situ ch...

Piton de la Fournaise is one of the world's most active and visited volcanoes. Its summit crater (Cratère Dolomieu), the main tourist attraction, underwent a major caldera collapse in 2007 and its rim is not yet stabilized. In order to assess the caldera rim instability risk for visitors, we followed its structural evolution from 2007 to 2015. Usin...

In this study, we examine the channel-fed ‘a‘ā lava flow system that was emplaced during a very short (less than 15 h long) eruption at Piton de la Fournaise (La Réunion) in December 2010. The system had four branches, the longest of which was 1100 m long. Three branches were emplaced over a smooth-surfaced pāhoehoe flow field with a vertical relie...

We have analysed the impact of different forcings, such as rain and seismicity, on slope instabilites on an active volcano. For this, we compiled a catalog of the locations and volumes of rockfalls in the Piton de la Fournaise crater using seismic records. We validated it by comparing the locations and volumes to those deduced from photogrammetric...

Anticipating eruptions early enough to give warning to authorities is one of the main goals in volcanology. However, identifying and providing unequivocal identification on volcano reawakening remain challenging issues, mostly when unrests are sudden or undetectable. At the Piton de la Fournaise volcano, a clear increase in both the seismicity and...

An analysis of the front pages of 120 consecutive editions of the local newspaper for the island of La Réunion (France), “Le Journal de L’Ile de La Réunion”, published before, during and after the April 2007 eruption of Piton de la Fournaise reveals that its front page is an ideal vehicle for maximizing information delivery and recall during a volc...

During March, April and May 2007 the local newspaper for the island of La Réunion, “Le Journal de L’Ile de La Réunion” (JIR), published 427 articles relating to natural hazards, with hazard-related articles occupying a total paper area of 21.94 m² and appearing in all but four of the 90 editions of the newspaper. This high level of coverage was due...

The 2014 eruption at Piton de la Fournaise (PdF), La Réunion, which occurred after 41 months of quiescence, began with surprisingly little precursory activity and was one of the smallest so far observed at PdF in terms of duration (less than 2 days) and volume (less than 0.4 × 10⁶ m³). The pyroclastic material was composed of golden basaltic pumice...

Photoscan automated report of processing of hand-held aerial photography data acquired on 23 May 2015 from a light airplane above Cratère Dolomieu, La Réunion, France.

Photoscan automated report of processing of hand-held aerial photography data acquired on 07 April 2015 from a light airplane above Cratère Dolomieu, La Réunion, France.

The 2014 eruption at Piton de La Fournaise (PdF), la Reunion, which occurred after 41 months of quiescence, began with surprisingly little precursory activity, and was one of the smallest so far observed at PdF in terms of duration (less than 2 days) and volume (less than 0.4 Mm³). The pyroclastic material was composed of spiny-opaque, spiny-irides...

Channel-fed lava flow systems lack detailed thermal and textural studies through the boundary between channelized and dispersed flow, and out to the flow front. Here, chemical, textural and morphological analyses were made to define cooling and crystallisation rates down the entire system, especially through the zone of dispersed flow. We compare t...

Peripheral diffuse degassing of CO2 from the soil occurs across the western flank of Piton de la Fournaise volcano (La Réunion Island, Indian Ocean) along a narrow zone. In this area, carbon isotopic analysis on soil gas samples highlights significant mixing between magmatic and organic end-members. The zones with the strongest magmatic signature (...

Many active European volcanoes and volcano observatories are island-based and located far from their administrative " mainland ". Consequently, Governments have developed multisite approaches, in which monitoring is performed by a network of individuals distributed across several national research centers. At a transnational level, multinational ne...

Monitoring ground surface displacement of volcanoes over a long period of time helps improve understanding of the volcano structure, dynamics and mechanisms. In this paper, we investigate the spatio-temporal behavior of the long-term displacement field at Piton de la Fournaise volcano (La Réunion Island) by means of X-band InSAR and GNSS time serie...

The STRAP (Synergie Transdisciplinaire pour Répondre aux Aléas liés aux Panaches volcaniques) campaign was conducted over the entire year of 2015 to investigate the volcanic plumes of Piton de La Fournaise (La Réunion, France). For the first time, measurements at the local (near the vent) and at the regional scales were conducted around the island....

Le Service d’Observation OI2 (Observatoire InSAR de l’Océan Indien) de l’Observatoire de Physique du Globe de Clermont-Ferrand a pour objectif principal la production et la distribution de mesures de déplacements du sol, régulières et pérennes, sur le Piton de la Fournaise. Ces mesures sont obtenues par le traitement de données d’interférométrie ra...

InSAR and GNSS are now the best and most developed techniques in the Earth sciences to track deformation, especially in volcanology. In this study, we assess the reliability and consistency of these two techniques for measuring 3-D ground displacements - and not only the displacement in the direction of the InSAR Line of Sight - on volcanoes during...

Photoscan automated report of processing of hand-held aerial photography data acquired on 04 October 2008 from a light airplane above Cratère Dolomieu, La Réunion, France.

Photoscan automated report of processing of hand-held aerial photography data acquired on 18 December 2008 from a light airplane above Cratère Dolomieu, La Réunion, France.

Lava flows occur worldwide, and throughout history, various cultures (and geologists) have described flows based on their surface textures. As a result, surface morphology-based nomenclature schemes have been proposed in most languages to aid in the classification and distinction of lava surface types. One of the first to be published was likely th...

The STRAP (Synergie Transdisciplinaire pour Répondre aux Aléas liés aux Panaches volcaniques) campaign was conducted in 2015 to investigate the volcanic plumes of Piton de La Fournaise (La Réunion, France). For the first time, measurements at the local (near the vent) and at the regional scales around the island were conducted. The STRAP 2015 campa...

With very high rainfall, steep slopes and young reliefs, La Réunion Island is renowned for its highest erosion rates worldwide. The erosion mainly occurs by rockfalls and landslides in the steep sides of the river canyons. Most sediment is transported from inland to the sea via rivers and streams. River channels are formed by incision into the basa...

FLOWGO is a one-dimensional model that tracks the thermorheological evolution of lava flowing down a channel. The model does not spread the lava but, instead, follows a control volume as it descends a line of steepest descent centred on the channel axis. The model basis is the Jeffreys equation for Newtonian flow, modified for a Bingham fluid, and...

Measurements on the Dolomieu crater on La Réunion by LiDAR and SfM

Measurements on the Dolomieu crater on La Réunion by LiDAR and SfM

Measurements on the Dolomieu crater on La Réunion by LiDAR and SfM.

Measurements on the Dolomieu crater on La Réunion by LiDAR and SfM.

Identifying the onset of volcano unrest and providing an unequivocal identification of volcano reawakening remain challenging problems in volcanology. At Piton de la Fournaise, renewal of eruptive activity in 2014–2015, after 41 months of quiescence and deflation, was associated with long-term continuous edifice inflation measured by GNSS. Inflatio...

RED SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modelling and response communities with experience in tracking volcanic effusive events. The group first met during a three day-long workshop held in Clermont Ferrand (France) between 28 and 30 May 201...

Accurate and fast delivery of information about recent lava flows is important for near-real-time monitoring of eruptions. Here, we have characterized the October 2010 lava flow at Piton de la Fournaise using various InSAR datasets. We first produced a map of the area covered by the lava flow (i.e. Arealava = 0.71–0.75 km^2) using the coherence of...

Noise-based seismology is proving to be a complementary approach to active-source or earthquake-based methods for imaging and monitoring the Earth’s interior. Until recently, however, noise-based imaging and monitoring relied mostly on the inversion of surface waves reconstructed from correlations of mostly microseismic seismic noise (around 5 s of...

The Dolomieu crater on the Piton de la Fournaise is a very active area in terms of volcanic activity and seismicity. As a consequence of the seismicity, the topographic conditions and the high amounts of rainfall, a lot of geomorphic processes are involved in reworking the volcanic rocks and sediments, showing high magnitudes and short frequencies....

Much work has been done on Karthala volcano over the last 30 years concerning the volcanology, structural geology, petrology, geochemistry and geophysics. We focus here on the current state of knowledge about the structure of this typical shield volcano and its recent eruptive activity. Karthala is a large basaltic shield volcano with a typical “Ha...