Mike R James

Lancaster University | LU · Lancaster Environment Centre

Topographic measurements for detailed studies of processes such as erosion or mass movement are usually acquired by expensive laser scanners or rigorous photogrammetry. Here, we test and use an alternative technique based on freely available computer vision software which allows general geoscientists to easily create accurate 3D models from field p...

High resolution digital elevation models (DEMs) are increasingly produced from photographs acquired with consumer cameras, both from the ground and from unmanned aerial vehicles (UAVs). However, although such DEMs may achieve centimetric detail, they can also display systematic broad-scale error that restricts their wider use. Such errors which, in...

Unoccupied aircraft systems (UAS) are developing into fundamental tools for tackling the grand challenges in volcanology; here, we review the systems used and their diverse applications. UAS can typically provide image and topographic data at two orders of magnitude better spatial resolution than space-based remote sensing, and close-range observat...

UAVs and structure‐from‐motion photogrammetry enable detailed quantification of geomorphic change. However, rigorous precision‐based change detection can be compromised by survey accuracy problems producing systematic topographic error (e.g. ‘doming’), with error magnitudes greatly exceeding precision estimates. Here, we assess survey sensitivity t...

Structure-from-motion (SfM) photogrammetry is revolutionising the collection of detailed topographic data, but insight into geomorphological processes is currently restricted by our limited understanding of SfM survey uncertainties. Here, we present an approach that, for the first time, specifically accounts for the spatially variable precision inh...

Volcanic plumes pose a hazard to health and society and a particular risk for aviation. Hazard mitigation relies on forecasting plume dispersion within the atmosphere over time. The accuracy of forecasts depends on our understanding of particle dispersion and sedimentation processes, as well as on the accuracy of model input parameters, such as the...

Volcanic ash advisories are produced by specialised forecasters who combine several sources of observational data and volcanic ash dispersion model outputs based on their subjective expertise. These advisories are used by the aviation industry to make decisions about where it is safe to fly. However, both observations and dispersion model simulatio...

Blue spaces have long been associated with beneficially impacting human health and wellbeing. This article reflects upon the impact of the COVID-19 pandemic on people’s experiences in coastal blue space and the health and wellbeing benefits derived from exposure to the space. Undertaken after the UK’s first lockdown during Summer 2020, the work emp...

The deformation style of active volcanoes can provide insight into the structural evolution of their edifices, volcanic activity and associated hazards. The Somma‐Vesuvius volcano is considered one of the most dangerous on the planet due to its proximity to the megacity of Naples (Southern Italy). Thus, understanding its deformation style and corre...

Volcanic ash advisories are produced by specialised forecasters who combine several sources of observational data and volcanic ash dispersion model outputs based on their subjective expertise. These advisories are used by the aviation industry to make decisions about where it is safe to fly. However, both observations and dispersion model simulatio...

The opening of magmatic hydraulic fractures is an integral part of magma ascent, the triggering of volcano seismicity, and defusing the explosivity of ongoing eruptions via outgassing magmatic volatiles. If filled with pyroclastic particles, these fractures can be recorded as tuffisites. Tuffisites are therefore thought to play a key role in both i...

Spatially-distributed values of glacier aerodynamic roughness ( z 0 ) are vital for robust estimates of turbulent energy fluxes and ice and snow melt. Microtopographic data allow rapid estimates of z 0 over discrete plot-scale areas, but are sensitive to data scale and resolution. Here, we use an extensive multi-scale dataset from Hintereisferner,...

Volcanic ash poses a significant hazard for aviation. If an ash cloud forms as result of an eruption, it forces a series of flight planning decisions that consider important safety and economic factors. These decisions are made using a combination of satellite retrievals and volcanic ash forecasts issued by Volcanic Ash Advisory Centres. However, f...

Technological developments in the last few decades allow generation of increasingly high-resolution digital elevation models (DEMs), useful in many fields of Earth and environmental science, and especially for tectonic geomorphic studies. Combined with falling costs and the improved accuracy of geo-referencing using satellite geodetic tools based o...

Bubble nucleation and growth dynamics exert a primary control on the explosivity of volcanic eruptions. Numerous theoretical and experimental studies aim to capture the complex process of melt vesiculation, whereas textural studies use vesicle populations to reconstruct magma behaviour. However, post-fragmentation vesicu-lation in rhyolitic bombs c...

Gully erosion is a severe way of land degradation. Gullies threaten the sustainability of agro-ecosystems, causing quantitative and qualitative reduction of groundwater, farmland productivity, and waterways sedimentation. Since the gully development on the surface begins with water flow and sheet erosion, accurate monitoring of the erosive processe...

Sheet erosion is common on agricultural lands, and understanding the dynamics of the erosive process as well as the quantification of soil loss is important for both soil scientists and managers. However, measuring rates of soil loss from sheet erosion has proved difficult due to requiring the detection of relatively small surface changes over exte...

Highlights: • Suite of high temperature bubble growth experiments performed on a rhyolitic bomb from the 2008 eruption of Chaitén volcano • Hot-stage microscopy allowed the tracing of in-situ bubble growth at different temperatures • Experimentally derived growth rates placed in context of a cooling volcanic bomb to determine the amount of post-fra...

Video of Chaiten obs 3 heated to 725 deg. C at 200 deg.C/min using a hot stage microscope at Lancaster University.

Video of Chaiten obs 3 heated to 875 deg. C at 200 deg.C/min using a hot stage microscope at Lancaster University.

Accelerated soil erosion can result in substantial declines in soil fertility and has devastating environmental impacts. Consequently, understanding if rates of soil erosion are acceptable is of local and global importance. Herein we use empirical soil erosion observations collated into an open access geodatabase to identify the extent to which exi...

La dinámica del crecimiento de las burbujas ejerce un control primario sobre la explosividad de las erupciones volcánicas, pero las complejidades de la dinámica de la nucleación y el crecimiento siguen siendo poco conocidos. La vesiculación posterior a la fragmentación en pómez y bombas riolíticas puede crear texturas finales de burbujas enfriadas,...

With the increasing role that unmanned aerial systems (UAS) are playing in data collection for environmental studies, two key challenges relate to harmonizing and providing standardized guidance for data collection, and also establishing protocols that are applicable across a broad range of environments and conditions. In this context, a network of...

The original version of this article unfortunately contained a mistake. The text accompanying Eq. 3 in the published paper should be corrected.

Physical interactions between bubbles and crystals affect gas migration and may play a major role in eruption dynamics of crystal-rich magmas. Strombolian eruptions represent an end member for bubble-crystal interactions, in which large bubbles (significantly larger than the crystal size) rise through a crystal-rich near-surface magma. Indeed, volc...

Calculation of the sensible and latent heat (turbulent) fluxes is required in order to close the surface energy budget of glaciers and model glacial melt. The aerodynamic roughness length, z0, is a key parameter in the bulk approach to calculating sensible heat flux; yet, z0 is commonly considered simply as a tuning parameter or generalized between...

Volcanic ash injected into the atmosphere during explosive eruptions causes a hazard to the natural and built environment, human health and aviation. Ash dispersal is currently forecast with numerical models, the accuracy of which is strongly influenced by the quality of the volcanic source term parameters, e.g. particle size and shape distribution...

Supraglacial lake drainage events influence Greenland Ice Sheet dynamics on hourly to interannual timescales. However, direct observations are rare, and, to date, no in situ studies exist from fast-flowing sectors of the ice sheet. Here, we present observations of a rapid lake drainage event at Store Glacier, west Greenland, in 2018. The drainage e...

Water erosion affects all types of soils around the world at different intensities. However, in the tropics, water-based processes are the most important of the erosion processes and have received much attention in the last decades. Understanding and quantifying the processes involved in each type of water erosion (sheet, rill and gully erosion) is...

Dispersion of volcanic ash often causes not only a hazard to health and environment, but also a risk to aviation. How ash may impact human activity and aviation is currently forecast with numerical models. Their accuracy largely depends on the accuracy of their input parameters, or the 'source term' , which describe the initial ash characteristics...

We present the evolution over 3 months of a 2016-2017 pāhoehoe flow at Kīlauea as it changed from a narrow sheet flow into a compound lava field fed by a stable system of tubes. The portion of the flow located on Kīlauea’s coastal plain was characterized using helicopter-based visible and thermal structure-from-motion photogrammetry to construct a...

As a topographic modelling technique, structure from motion (SfM) photogrammetry combines the utility of digital photogrammetry with a flexibility and ease of use derived from multi‐view computer vision methods. In conjunction with the rapidly increasing availability of imagery particularly from unmanned aerial vehicles, SfM photogrammetry represen...

Generating high resolution spatial information on the movement of sediment in response to soil erosion remains a major research challenge. In this paper we present a new tracing method that utilises LED (light emitting diode) light to induce fluorescence in a sand-sized tracer, which is then detected, using a complementary metal oxide semiconductor...

Structure-from-motion (SfM) photogrammetry techniques are now widely available to generate digital terrain models (DTMs) from optical imagery, providing an alternative to costlier options such as LiDAR or satellite surveys. SfM could be a useful tool in hazard studies because its minimal cost makes it accessible even in developing regions and its s...

Understanding lava flow processes is important for interpreting existing lavas and for hazard assessments. Although substantial progress has been made for basaltic lavas our understanding of silicic lava flows has seen limited recent advance. In particular, the formation of lava flow breakouts, which represent a characteristic process in cooling-li...

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...

Your personalized Share Link: https://authors.elsevier.com/a/1Wtov7qzSjU11 Volcanic ash clouds can present an aviation hazard over distances of thousands of kilometres and, to help to mitigate this hazard, advanced numerical models are used to forecast ash dispersion in the atmosphere. However, forecast accuracy is usually limited by uncertainties...

Rhyolites comprise the most silica-rich lavas, and rhyolitic lava flows can reach tens of kilometres in length. Interpretations of ancient and historic rhyolite lava flows suggest protracted emplacement due to relatively slow cooling of these massive bodies and have identified late stage events such as the formation of pumice diapirs. However, our...

This paper proposes a coastal erosion monitoring system for beach erosion management, which we demonstrate on natural and artificial pocket gravel beaches in Croatia. The approach uses low-cost Structure-from-Motion (SfM) photogrammetric imaging and multi-view stereo (MVS) to produce high-resolution 3D beach models for detecting morphological chang...

The following exercise was compiled as part of the IAVCEI ‘Drone’ workshop, held on 13th August, 2017 in Portland, USA. Completing the exercise should enable you to: • Process UAV image data in PhotoScan to create DEMs and orthomosaics. • Refine your SfM processing approach to increase reproducibility through rigorous consideration of outliers, err...

Strombolian volcanism is a ubiquitous form of activity, driven by the ascent and bursting of bubbles of slug morphology. Whilst considerable attention has been devoted to understanding the behaviour of individual slugs in this regime, relatively little is known about how inter-slug interactions modify flow conditions. Recently, we reported on high...

Measurements of glacier ice cliff evolution are sparse, but where they do exist, they indicate that such areas of exposed ice contribute a disproportionate amount of melt to the glacier ablation budget. We used Structure from Motion photogrammetry with Multi-View Stereo to derive 3-D point clouds for nine ice cliffs on Khumbu Glacier, Nepal (in Nov...

The eruption and emplacement mechanisms of rhyolite lava flows remain enigmatic due to the infrequency with which these eruptions occur. The 2011-2012 eruption of Cordón Caulle in Chile provided the first opportunity to make detailed scientific observations of the active emplacement of an extensive rhyolite lava flow and thus offers an unparalleled...

The interpretation of geophysical measurements at active volcanoes is vital for hazard assessment and for understanding fundamental processes such as magma degassing. For Strombolian activity, interpretations are currently underpinned by first-order fluid dynamic models which give relatively straightforward relationships between geophysical signals...

Accurate forecasts of lava flow length rely on estimates of eruption and magma properties and, potentially more challengingly, on an understanding of the relative influence of characteristics such as the apparent viscosity, the yield strength of the flow core, or the strength of the lava's surface crust. For basaltic lavas, the relatively high freq...

Aerial image capture has become very common within the geosciences due to the increasing affordability of low-payload (<20 kg) unmanned aerial vehicles (UAVs) for consumer markets. Their application to surveying has subsequently led to many studies being undertaken using UAV imagery and derived products as primary data sources. However, image quali...

Structure-from-motion (SfM) algorithms greatly facilitate the generation of 3-D topographic models from photographs and can form a valuable component of hazard monitoring at active volcanic domes. However, model generation from visible imagery can be prevented due to poor lighting conditions or surface obscuration by degassing. Here, we show that t...

Quantifying the extent of soil erosion at a fine spatial resolution can be time consuming and costly; however, proximal remote sensing approaches to collect topographic data present an emerging alternative for quantifying soil volumes lost via erosion. Herein we compare terrestrial laser scanning (TLS), and both aerial (UAV) and ground-based (GP) S...

Very little is known about how individual soil particles move over a soil surface as a result of rainfall. Specifically there is virtually no information about the pathway a particle takes, the speed at which it travels and when it is in motion. Here we present a novel technique that can give insight into the movement of individual soil particles....

Structure-from-motion (SfM) algorithms greatly facilitate the production of detailed topographic models from photographs collected using unmanned aerial vehicles (UAVs). However, the survey quality achieved in published geomorphological studies is highly variable, and sufficient processing details are never provided to understand fully the causes o...

The surface deformation field measured at volcanic domes provides insights into the effects of magmatic, gravity-, and gas-driven processes, as well as the development and distribution of internal dome structures. Here we study short term dome deformation associated with earthquakes at Mount St. Helens, recorded by a permanent optical camera and se...

Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus...

We present UV camera data for 200 strombolian and hornito degassing events at Stromboli during June and July 2014. This data was processed to calculate SO 2 masses for each event. In addition to calculating SO 2 masses of the slugs which generate these events we also observe periods of elevated flux following events, termed the gas coda, lasting ≈...

Textural and petrological evidence has indicated the presence of viscous, degassed magma layers at the top of the conduit at Stromboli. This layer acts as a plug through which gas slugs burst and it is thought to have a role in controlling the eruptive dynamics. Here, we present the results of laboratory experiments which detail the range of slug f...

Here we use field observations of rhyolite and basalt lava flows to show similarities in flow processes that span compositionally diverse lava flows. The eruption, and subsequent emplacement, of rhyolite lava flows is currently poorly understood due to the infrequency with which rhyolite eruptions occur. In contrast, the emplacement of basaltic lav...

Bu bildiri heyelanların izlenmesinde insansız hava araçlarından (İHA) elde edilen yüksek çözünürlüklü verilerin kullanılmasında yöntem ve metotların araştırılmasını kapsamaktadır. İHA’lar ile elde edilen yüksek çözünürlüklü verilerin deformasyon analizleri kullanılarak heyelanların hareketlerinin izlenmesini, boyutlarını ve hacimsel olarak hareket...

During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily), we make the first measurements based on terrestrial laser scanning (TLS), and we also include explosi...

Glavica (natural) and Dugi Rat (artificial) gravel beaches in Croatia were monitored using ground-based photography and structure-from-motion (SfM) photogrammetry, in order to assess morphological changes after storm events. In contrast to stormy waves caused by Bora winds (NE), Sirocco winds (SE) induced waves which initiated morphological changes...

Strombolian activity is characterized by quasi­periodic, short­lived explosions, which vary greatly in magnitude. The explosions are understood to be driven by the bursting of large, overpressured 'slugs' of magmatic gas, which have ascended the conduit. We use scaled laboratory analogue experiments and numerical modelling to investigate the impact...