Andrew Harris

Université Clermont Auvergne | Univ BPC · Laboratoire Magmas et Volcans

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...

ASHER, a new sensor for the characterization of tephra fallout in real time, was designed and developed for easy field deployment during volcanic eruptions. It can provide information on the accumulation rate of tephra fallout in real time as well as grain-size and settling velocity of falling particles. Particle detection is achieved with a laser...

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...

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...

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...

Low elevation flank eruptions represent highly hazardous events due to their location near, or in, communities. Their potentially high effusion rates can feed fast moving lava flows that enter populated areas with little time for warning or evacuation, as was the case at Nyiragongo in 1977. The January-March 1974 eruption on the western flank of Mo...

Because many volcanoes are densely vegetated, understanding of the interactions between active lava flows and trees is essential for robust hazard modeling. Tree molds − lava flow features generated when advancing lava engulfs and combusts trees − are widely documented but have, to date, only been described qualitatively. Detailed, quantitative stu...

Reconstructing bomb trajectories resulting from Strombolian activity can provide insights into near-surface dynamics of the conduit system. Typically, the high number of bombs involved represents a challenge for both automatic and manual bomb identification and tracking methods. Here, we present a method for the automated recognition of hundreds of...

Emplacement of silicic lava flows has rarely been observed. To constrain their dynamics, we need to analyze past flows. The study of structures and textures, at macro- and micro-scale, allow us to reconstruct the history of a lava flow. Structures such as folds and faults are used to infer the state (ductile versus brittle) of the lava at a given t...

To examine whether there was any physical or thermal interaction between trees and lava when a lava flow inundates a forest, we studied the Kīlauea’s July 1974 lava flow. We mapped the location of ∼ 600 lava-trees and the lava type (pāhoehoe versus ‘a‘ā), and sampled an additional ten lava-trees for chemical and textural analysis to infer flow visc...

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...

Viscosity is one of the most important physical properties controlling lava flow dynamics. Usually, viscosity is measured in the laboratory where key parameters can be controlled but can never reproduce the natural environment and original state of the lava in terms of crystal and bubble contents, dissolved volatiles, and oxygen fugacity. The most...

Viscosity is one of the most important physical properties controlling lava flow dynamics. Usually, viscosity is measured in the laboratory where key parameters can be controlled but can never reproduce the natural environment and original state of the lava in terms of crystal and bubble contents, dissolved volatiles, and oxygen fugacity. The most...

During an eruption, time scales of topographic change are fast and involve vertical and planimetric evolution of millimeters to meters as the event progresses. Repeat production of high spatial resolution terrain models of lava flow fields over time scales of a few hours is thus a high-value capability in tracking the buildup of the deposit. Among...

Volcanic plumes are turbulent mixtures of particles and gas which are injected into the atmosphere during a volcanic eruption. Depending on the intensity of the eruption, plumes can rise from a few tens of metres up to many tens of kilometres above the vent and thus, present a major hazard for the surrounding population. Currently, however, few if...

Small-volume proximal eruptions are common at Piton de la Fournaise (La Reunion Island, France). However, the mechanisms driving such basaltic eruptions are still not completely understood. To gain insight, we focused on a well-constrained multidisciplinary dataset for the two short-lived (~2 day-long) eruptions of June 2014 (0.4 million m3) and Ju...

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...

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...

Puffing, i.e., the frequent (1 s ca.) release of small (0.1–10 m³), over-pressurized pockets of magmatic gases, is a typical feature of open-conduit basaltic volcanoes worldwide. Despite its non-trivial contribution to the degassing budget of these volcanoes and its recognized role in volcano monitoring, detection and metering tools for puffing are...

Strombolian eruptions are amongst the most common subaerial explosive volcanism worldwide. Distinctive features of each volcano lead to a correspondingly wide range of variations of magnitude and erupted products, but most papers focus on a single type of event at a single volcano. Here, in order to emphasize the common features underlying this div...

We present a workflow to create, scale, georeference, and integrate digital elevation models (DEMs) created using open-source structure-from-motion (SfM) multiview stereo (MVS) software into existing DEMs (as derived from the light detection and ranging data in the presented cases). The workflow also maps the root-mean-square error between the base...

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...

RED-SEED stands for Risk Evaluation, Detection and Simulation during Effusive Eruption Disasters, and combines stakeholders from the remote sensing, modeling and response communities with experience in tracking volcanic effusive events. It is an informal working group that has evolved around the philosophy of combining global scientific resources,...

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...

Since 1999, Mount Etna’s (Italy) South-East crater system has been characterised by episodic lava fountaining. Each episode is characterised by initial strombolian activity followed by transition to sustained fountaining to feed high-effusion rate lava flow. Here, we use thermal infrared data recorded by a permanent radiometer station to characteri...

Over the past fifty years, a diverse set of thermal infrared (TIR) remote sensing data has been acquired from the orbits of Earth and Mars, which both have ubiquitous volcanic landforms. These data vary in spatial, spectral and temporal resolution and are critical for investigating an ever-expanding set of science applications including the focus o...

Editor: T.A. Mather Keywords: explosions pulsatory activity magma viscosity repose interval source dynamics eruptive style Pulsatory eruptions are marked by a sequence of explosions which can be separated by time intervals ranging from a few seconds to several hours. The quantification of the periodicities associated with these eruptions is essenti...

This chapter deals with the morphology and rheology of terrestrial basaltic and silicic lava flows. Here we take a facies-based approach, describing each lava type in terms of its typical geometry, texture, structures, movement patterns and incorporation of alien objects. Using such an approach we distinguish the three classically defined types of...

Thermal anomalies occur when a pixel in a satellite image shows a higher brightness temperature than is expected relative to its neighbors. Thermal anomalies have been observed over decades at volcanoes in satellite data. Such anomalies occur for many reasons, but at volcanoes this can be an indicator of volcanic activity or even a precursor to mor...

The effect of a volcanic eruption by liberating magma, gases, and energy is to modify the Earth’s surface and its atmosphere. Quite how these changes are produced depends on the nature of the eruption; for example, whether it is explosive or effusive, the period of time over which the eruption occurs, the mass of material erupted, and the geographi...

Using two hypothetical effusive events in the Chaîne des Puys (Auvergne, France), we tested two geographical information systems (GISs) set up to allow loss assessment during an effusive crisis. The first was a local system that drew on all immediately available data for population, land use, communications, utility and building type. The second wa...

Recently, we have developed a methodology for the retrieving of some key vent parameter and their related uncertainly by analyzing Thermal Infrared (TIR) videos of volcanic plumes (cf. Cerminara et al. JVGR 2015). We have applied this inversion procedure to an ash plume at Santiaguito (Santa Maria volcano, Guatemala). In particular, our methodology...

A workshop entitled "Tracking and understanding volcanic emissions through cross-disciplinary integration: a textural working group" was held at the Université Blaise Pascal (Clermont-Ferrand, France) on the 6–7 November 2012. This workshop was supported by the European Science Foundation (ESF). The main objective of the workshop was to establish a...

This paper presents two algorithms for feature extraction and segmentation. The first algorithm is applied to detect tens of thousands of ballistic targets moving at high velocities (100’s m/s) and with different sizes, velocities, shapes and directions. Upon detection, we compute statistics for each of these parameters for each particle, without a...

This review is split into two parts both of which address issues of forecast communication of an environmental disaster through the newspaper during a period of crisis. The first part explores the process by which information passes from the scientist or forecaster, through the media filter, to the public. As part of this filter preference, omissio...

In the first part of this review, I defined the media filter and how it can operate to frame and blame the forecaster for losses incurred during an environmental disaster. In this second part, I explore the meaning and role of uncertainty when a forecast, and its basis, is communicated through the response and decision-making chain to the newspaper...

Over the past decade, a proliferation of new technologies has pushed forward our ability to measure the dynamics of volcanic emissions as they exit, and ascend above, the vent. Measuring parameters of all particles as they exit the vent during an explosive eruption is the best way to gather parameters such as size, shape, velocity and mass for the...

A new version of the thermo-rheological lava flow model FLOWGO allows (i) incorporation of new rheological relations, (ii) use of stochastic lava flow path models, and (iii) greater flexibility to allow best-fitting of model output with natural data. We apply the model to four channel-fed lava flows for which good field data exist. These include Ma...

Textural and chemical analyses of bombs quenched directly from a normal explosion at Stromboli volcano (Italy) were integrated with coincident seismic, acoustic, and thermal data. The data set defines a new gas-dominated type of “strombolian” eruption, named type 0. These events are characterized by high-velocity emission (150–250 m s−1) of a few r...

Close to becoming part of a UNESCO world heritage site, the Chaine des Puys monogenetic alignment has > 80 effusive centers. Lava flows extending east enter valleys cut into the Limagne fault scarp. Flow emplacement dynamics depend on the slope of the terrain. We focus here on two cases: (i) the Grave Noire (60 ka) lavas – emplaced on steep slopes...

Normal activity at Stromboli (Aeolian Islands, Italy) can be broadly divided into (1) puffing, where small amounts of gas are emitted without pyroclasts at a rate of ~1 per second; and (2) "normal" explosions, where gas and pyroclast mixtures are expelled up to several hundred meters high (at rates of 1­10 events per hour). In May 2014, we monitore...

asaltic lavas collected at the Muliwai a Pele lava channel, built during 1974 as part of Mauna Ulu’s eruption on Kilauea’s east rift zone, have been studied to investigate the effect of cooling and crystallization on the rheological prop- erties of the lava. We have quantified the viscosity-strain-rate dependence of lava during cooling and crystall...

We present simultaneous measurements of gas and solid emissions from Strombolian explosions acquired on Stromboli volcano on 30 September 2012 using an SO2 camera and an infrared camera. We find no significant correlation between solid and gas masses, consistent with the postulated independence of the processes controlling bubble film rupture and g...

Over the last decade, feature tracking and recognition in infrared (IR) video has become an important strategy used in many applications. To achieve such a capability, we developed a method based on the top-hat transform, hybridized with refinement by thresholding. Our algorithm uses two different but correlated background subtraction approaches to...

A small motor controller (SMC) system includes a motor configured to control a position of a rotor, a sensor configured to detect position information of the rotor by detecting a feature on the rotor, the sensor including a detection zone having a first side and a second side, and a motor control unit. The motor control unit is configured to determ...

The Muliwai a Pele lava channel was emplaced during the final stage of Mauna Ulu’s 1969–1974 eruption (Kilauea, Hawaii). The event was fountain-fed, lasted around 50 h, during which a channelized flow system developed, where a 6-km channel fed a zone of dispersed flow that extended a further 2.6 km. The channel was surrounded by initial rubble leve...

We present a coupled fluid-dynamic and electromagnetic model for volcanic ash plumes. In a forward approach, the model is able to simulate the plume dynamics from prescribed input flow conditions and generate the corresponding synthetic thermal infrared (TIR) image, allowing a comparison with field-based observations. An inversion procedure is then...

Fissure eruption on the slope of Plosky Tolbachik volcano continued from November 27th, 2012 until September 2013. It was named as The Institute of Volcanology and Seismology 50th Anniversary Fissure Tolbachik Eruption. The eruption started from the 5 km-long fissure opening and continued with the intensive lava effusion from it. During the first t...

[1] The type of explosive activity known as strombolian is characterized by repeated, low energy, explosions and is named after the volcano where such activity has persisted for around 2000 years, i.e., Stromboli (Aeolian Islands, Italy). Because activity is virtually guaranteed, Stromboli represents an excellent laboratory where measurements of th...

Effective user control of highly dexterous and robotic assistive devices requires intuitive and natural modalities. Although surgically implanted brain-computer interfaces (BCIs) strive to achieve this, a number of non-invasive engineering solutions may provide a quicker path to patient use by eliminating surgical implantation. We present the devel...

Due to its massive air traffic impact, the 2010 eruption of Eyjafjallajökull was felt by millions of people and cost airlines more than U.S. $1.7 billion. The event has, thus, become widely cited in renewed efforts to improve real-time tracking of volcanic plumes, as witnessed by special sections published last year in Journal of Geophysical Resear...

A thermal infrared thermometer was used to record the passage of hot gases and fragments across a measurement area located at the exit of one of Yasur's active vents. Recording was completed over 2 hours during September 2011. A total of 200 explosive events were recorded. We define two types of event. Low energy events with typical thermal energie...

We propose a novel approach to studying a ballistic bomb deposit. Favorable circumstances, a unique dispersal axis, an operational thermal video camera, and application of an innovative methodology allowed estimates of volume and mass erupted, and definition of mass partitioning between bombs of various sizes. This allowed the creation of a multidi...

Masses erupted during normal explosions at Stromboli volcano (Italy) are notoriously difficult to measure. We present a method that uses thermal infrared video for cooling bomb fields to obtain the total power emitted by all hot particles emitted during an explosion. A given mass of magma (M) will emit a finite amount of thermal power, defined by M...

On April 14, 2010, an eruptive fissure opened in Iceland's Eyjafjallajökull glacier to trigger an explosive phase of t he eruption of Eyjafjöll volcano, initiating a phreatomagmatic stage due to the interaction of ice and magma. The eruption stopped some weeks later on May 23, leading to a dormant phase. The April 14 explosive activity of fed a clo...

Volcanological remote sensing spans numerous techniques, wavelength regions, data collection strategies, targets, and applications. Attempting to foresee and predict the growth vectors in this broad and rapidly developing field is therefore exceedingly difficult. However, we attempted to make such predictions at both the American Geophysical Union...

We apply a measurement technique that utilizes thermal video of vapor-dominated volcanic plumes to estimate the H2O gas flux at three degassing volcanoes. Results are compared with H2O flux measurements obtained using other methods to verify the thermal camera-derived values. Our estimation of the H2O emission rate is based on the mass and energy c...