Geosciences, Volume 7, Issue 3 (September 2017) – 48 articles

This paper presents the methodological approach and the actual workflow for creating the 3D digital reconstruction in time of the ancient Roman Circus of Milan, which is presently covered completely by the urban fabric of the modern city. The diachronic reconstruction is based on a proper mix of quantitative data originated by current 3D surveys and historical sources, such as ancient maps, drawings, archaeological reports, restrictions decrees, and old photographs. When possible, such heterogeneous sources have been georeferenced and stored in a GIS system. In this way the sources have been analyzed in depth, allowing the deduction of geometrical information not explicitly revealed by the material available. A reliable reconstruction of the area in different historical periods has been therefore hypothesized. This research has been carried on in the framework of the project Cultural Heritage Through Time—CHT2, funded by the Joint Programming Initiative on Cultural Heritage (JPI-CH), supported by the Italian Ministry for Cultural Heritage (MiBACT), the Italian Ministry for University and Research (MIUR), and the European Commission. Full article

The piezoelectric and seismo-electrokinetic phenomena are manifested by electrical and electromagnetic processes that occur in rocks under the influence of elastic oscillations triggered by shots or mechanical impacts. Differences in piezoelectric properties between the studied targets and host media determine the possibilities of the piezoelectric/seismoelectric method application. Over a long time, an interpretation of obtained data is carried out by the use of methods developed in seismic prospecting. Examination of nature of piezoelectric/seismoelectric anomalies observed in subsurface indicates that these may be related (mainly) to electric potential field. In this paper, it is shown that quantitative analysis of piezoelectric/seismoelectric anomalies may be performed by the advanced and reliable methodologies developed in magnetic prospecting. Some examples from mining geophysics (Russia) and ancient metallurgical site (Israel) confirm applicability of the suggested approach. Full article

The present study aims at understanding the role of the structure and the geometry of the weathering profile on the hydrodynamic behavior of hard rock aquifers. We first described 2D geophysical cross sections of weathering profiles realized and validated on an experimental site. Next, we implemented five long-term pumping tests in wells drilled at various locations of these cross sections. Finally, we chose the appropriate analytical solutions to determine the hydrodynamic parameters in consistence with the structure and the geometry of the weathering profile. Results reveal that land covers, weathering type and thickness, presence of no flow boundaries, etc. are all factors that explain the flow regime, which appears therefore much less unpredictable. In other words, the 2D geophysical data are enough to locate the best permeable areas, or the areas where the structure of the aquifer without impervious boundaries and with leakage favor a good long-term behavior of the well. The values of aquifer’s transmissivity vary between 5.10⁻³ and 4.10⁻⁵ m²/s. The storage varies between 0.06 and 7.10⁻⁷. The variability of these parameters from site to site reflects the high heterogeneity of hard rock aquifers. Full article

The objective of flood frequency analysis (FFA) is to associate flood intensity with a probability of exceedance. Many methods are currently employed for this, ranging from statistical distribution fitting to simulation approaches. In many cases the site of interest is actually ungauged, and a regionalisation scheme has to be associated with the FFA method, leading to a multiplication of the number of possible methods available. This paper presents the results of a wide-range comparison of FFA methods from statistical and simulation families associated with different regionalisation schemes based on regression, or spatial or physical proximity. The methods are applied to a set of 1535 French catchments, and a k-fold cross-validation procedure is used to consider the ungauged configuration. The results suggest that FFA from the statistical family largely relies on the regionalisation step, whereas the simulation-based method is more stable regarding regionalisation. This conclusion emphasises the difficulty of the regionalisation process. The results are also contrasted depending on the type of climate: the Mediterranean catchments tend to aggravate the differences between the methods. Full article

Multi-temporal synthetic aperture radar interferometry techniques (MT-InSAR) are nowadays a well-developed remote sensing tool for ground stability monitoring of areas afflicted by natural hazards. Its application capability has recently been emphasized by the Sentinel-1 satellite mission, providing extensive spatial coverage, regular temporal sampling and free data availability. We perform MT-InSAR analysis over the wider Upper Nitra region in Slovakia, utilizing all Sentinel-1 images acquired since November 2014 until March 2017. This region is notable for its extensive landslide susceptibility as well as intensive brown coal mining. We focus on two case studies, being impaired by recent activation of these geohazards, which caused serious damage to local structures. We incorporate a processing chain based on open-source tools, combining the current Sentinel Application Platform (SNAP) and Stanford Method for Persistent Scatterers (StaMPS) implementation. MT-InSAR results reveal substantial activity at both case studies, exceeding the annual displacement velocities of 30 mm/year. Moreover, our observations are validated and their accuracy is confirmed via comparison with ground truth data from borehole inclinometers and terrestrial levelling. Detected displacement time series provide valuable insight into the spatio-temporal evolution of corresponding deformation phenomena and are thus complementary to conventional terrestrial monitoring techniques. At the same time, they not only demonstrate the feasibility of MT-InSAR for the assessment of remediation works, but also constitute the possibility of operational monitoring and routine landslide inventory updates, regarding the free Sentinel-1 data. Full article

Archaeologists often rely on passive airborne optical remote sensing to deliver some of the core data for (European) landscape archaeology projects. Despite the many technological and theoretical evolutions that have characterised this field of archaeology, the dominant aerial photographic surveys, but also less common approaches to archaeological airborne reconnaissance, still suffer from many inherent biases imposed by sub-par sampling strategies, cost, instrument availability and post-processing issues. This paper starts with the concept of landscape (archaeology) and uses it to frame archaeological airborne remote sensing. After introducing the need for bias reduction when sampling an already distorted archaeological population and expanding on the ‘theory-neutral’ claim of aerial survey, the paper presents eight key characteristics that all have the potential to increase or decrease the subjectivity and bias when collecting airborne optical imagery with passive sensors. Within this setting, the paper then offers some technological-methodological reflection on the various passive airborne optical imaging solutions that landscape archaeology has come to rely upon in the past decades. In doing so, it calls into question the effectiveness and suitability of these highly subjective approaches for landscape archaeology. Finally, the paper proposes a new, more objective approach to aerial optical image acquisition with passive sensors. In the discussion, the text argues that the suggested exhaustive (or total) airborne sampling of the preserved archaeological record might transcend particular theoretical paradigms, while the data generated could span various interpretational perspectives and oppositional analytical approaches in landscape archaeology. Full article

In this paper, we investigate land motion and groundwater level change phenomena using differential interferometric synthetic aperture radar (DInSAR) over the Northumberland and Durham coalfield in the United Kingdom. The study re-visits earlier research that applied a persistent scatterers interferometry (PSI) technique to ERS (European Remote Sensing) and ENVISAT (Environmental Satellite) data. Here, the Intermittent Small Baseline Subset (ISBAS) DInSAR technique is applied to ERS, ENVISAT and Sentinel-1 SAR datasets covering the late 1990s, the 2000s and the mid-2010s, respectively, to increase spatial coverage, aid the geological interpretation and consider the latest Sentinel-1 data. The ERS data identify surface depressions in proximity to former collieries, while all three data sets ascertain broad areas are experiencing regional scale uplift, often occurring in previously mined areas. Uplift is attributed to increases in pore pressure in the overburden following the cessation of groundwater pumping after mine closure. Rising groundwater levels are found to correlate to ground motion measurements at selected monitoring sites, most notably in the surrounding area of Ashington. The area is divided by an impermeable EW fault; to the south, surface heave was identified as groundwater levels rose in the 1990s, whereas to the north, this phenomenon occurred two decades later in the 2010s. The data emphasize the complexity of the post-mining surface and subsurface environment and highlight the benefit that InSAR, utilizing the ISBAS technique, can provide in its characterization. Full article

Monitoring gaseous and particulate volcanic emissions with remote observations is of particular importance for climate studies, air quality and natural risk assessment. The concurrent impact of the simultaneous presence of sulphur dioxide (SO₂) emissions and the subsequently formed secondary sulphate aerosols (SSA) on the thermal infraRed (TIR) satellite observations is not yet well quantified. In this paper, we present the first assessment of the combined sensitivity of pseudo-observations from three TIR satellite instruments (the Infrared Atmospheric Sounding Interferometer (IASI), the MODerate resolution Imaging Spectro radiometer (MODIS) and the Spinning Enhanced Visible and InfraRed Imager (SEVIRI)) to these two volcanic effluents, following an idealized moderate stratospheric eruption. Direct radiative transfer calculations have been performed using the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model during short-term atmospheric sulphur cycle evolution. The results show that the mutual effect of the volcanic SO₂ and SSA on the TIR outgoing radiation is obvious after three to five days from the eruption. Therefore, retrieval efforts of SO₂ concentration should consider the progressively formed SSA and vice-versa. This result is also confirmed by estimating the information content of the TIR pseudo-observations to the bi-dimensional retrieved vector formed by the total masses of sulphur dioxide and sulphate aerosols. We find that it is important to be careful when attempting to quantify SO₂ burdens in aged volcanic plumes using broad-band instruments like SEVIRI and MODIS as these retrievals present high uncertainties. For IASI, the total errors are smaller and the two parameters can be retrieved as independent quantities. Full article

Research is needed by global change scientists on how global vegetation biomes respond to ongoing climate warming. To address this issue, we selected study sites with significant climate warming for diverse vegetation biomes, and used global gridded temperature and remote sensing data over the past 32 years (1982–2013). The results suggested that climate warming in areas above approximately 60° N is relaxing the heat-constraints on vegetation activity, thus promoting plant growth; whereas, in mid to low latitude areas, ongoing climate warming probably imposes negative impacts on vegetation biomes through drought and heat stress. Understanding these potential effects is important for planning adaptation strategies to mitigate the impacts of climate warming, particularly for agro-ecosystems. Full article

The Bruneau Woodpile site has long been popular among fossil collectors; however, the deposit has received scant attention from scientists. Our research reveals that the fossilized wood was deposited ca. 6.85 Ma, within the Chalk Hills Formation, and was mineralized with carbonate-fluorapatite. The diverse assemblage of conifers and hardwoods is representative of the warm temperate forests that flourished in southwest Idaho, USA during the late Miocene. Limb and trunk fragments preserved in a single thin sandstone bed appear to represent woody debris that was transported by streams. One possible explanation is that wood, pumice, and sandy volcaniclastic sediment arrived separately as a result of ordinary stream action, and later were combined into a single assemblage during a subsequent high-energy sedimentation event. We favor an alternate hypothesis: a catastrophic event (e.g., a windstorm) damaged trees on slopes bordering the ancient lake. Branches and small trunk fragments were carried by wind and rain into local streams and ponds where they became waterlogged. After a delay that allowed pumice and wood to become saturated, storm water transported these materials, along with finer volcaniclastic sediment, into a lake. The resulting density current produced a fining-upward sedimentary cycle where wood was preserved in the lowest, coarsest stratum. Full article

A combination of geophysical methods could be very a useful and a practical way of verifying the origin and precise localisation of archaeological situations identified by different remote sensing techniques. The results of different methods (and scales) of monitoring these fully non-destructive methods provide distinct data and often complement each other. The presented examples of combinations of these methods/techniques in this study (aerial survey, LIDAR-ALS and surface magnetometer or resistivity survey) could provide information on some specifics and may also be limitations in surveying different archaeological terrains, types of archaeological situations and activities. The archaeological site in this contribution is considered to be a material of this study. In case of Neolithic ditch enclosure near Kolín were compared aerial prospection data, magnetometer survey and aerial photo-documentation of excavated site. In the case of hillforts near Levousy we compared LIDAR data with aerial photography and large-scale magnetometer survey. In the case of the medieval castle Liběhrad we compared LIDAR data with geoelectric resistivity measurement. In case of a burial mound cemetery we combined LIDAR data with magnetometer survey. In the case of the production area near Rynartice we combined LIDAR data with magnetometer and resistivity measurements and result of archaeological excavation. Fortunately for successful combination of geophysical and remote sensing results, their conditions and factors for efficient use in archaeology are not the same. On the other hand, the quality and state of many prehistoric, early medieval, medieval and also modern archaeological sites is rapidly changing over time and both groups of techniques represent important support for their comprehensive and precise documentation and protection. Full article

The hazard index (HI) and carcinogenic risk due to the exposure of some potentially toxic elements to the Santiago Island (Cape Verde) population were calculated, considering soil ingestion, inhalation, and dermal contact as exposure pathways. The topsoil of Santiago Island, compared with that of the upper continental crust, is enriched with Co, Cr, Cu, Ni, V, Zn, Mn, and Cd. Hazard indices (HIs) for these metals and the As exposures to the Santiago Island population were calculated, and these calculations were performed for children and adults. For children, HIs were higher than 1 for Co, Cr, and Mn. Therefore, there is an indication of potential non-carcinogenic risk for children, due to the high Co (HI = 2.995), Cr (HI = 1.329), and Mn (HI = 1.126) values in these soils. For the other elements, in adults, there is no potential non-carcinogenic risk. Cancer risk for As, Cd, Cr, and Ni exposures, in adults and children, was calculated, and the results are mainly lower than the carcinogenic target risk of 1 × 10⁻⁶ for As, Cd, and Ni. However, in adults, cancer risk is higher than the carcinogenic target risk for Cr. Regarding As, for children, the fraction due to Risk_ingestion represents 51.6%, while Risk_inhalation represents 48.0% and Risk_{dermalcontact} represents only 0.4% of the total risk. For adults, Risk_inhalation represents 81.3%, Risk_ingestion represents 16.6%, and Risk_{dermal contact} represents 2.1%. These results reflect the higher daily ingestion dose for children and the higher inhalation rate and higher dermal contact surface for adults. For the other elements, the cancer risk due to Cr, Ni, and Cd inhalation is always higher for adults than it is for children, reflecting the higher inhalation rate for adults. Full article

The impressive hydraulic system built by the Assyrian King Sennacherib is composed by different archaeological areas, displaced along the Land of Nineveh, in Iraqi Kurdistan. The extensive project we are working on has the aim of mapping and geo-referencing any kind of documentation in order to design an archaeological-environmental park able to preserve and enhance the archaeological complex. Unfortunately, the area is failing a topographic documentation and the available cartography is not sufficient for planning and documentation purposes. The research work presented in these pages moves towards this direction, by exploiting Pleiadés Very High Resolution (VHR) images (in both nadir and stereo configuration) for an accurate mapping of the site. In more depth, Pleiadés nadir VHR images have been used to perform a pansharpening procedure used to enhance the visual interpretation of the study area, whilst stereo-pair have been processed to produce the Digital Elevation Model (DEM) of the study area. Statistical evaluations show the high accuracy of the processing and the reliability of the outputs as well. The integration of different products, at different Levels of Detail within a unique GIS environment, besides protecting, preserving and enhancing the water system of Sennacherib’s, paves the way to allow the Kurdistan Regional Government to present a proposal for the admission of the archaeological complex in the UNESCO World Heritage Tentative List (WHTL). Full article

The IGEAN (Innovative Geophysical Approaches for the study of Early Agricultural villages of Neolithic) Thessaly project focused on Early and Neolithic settlements in Thessaly, Central Greece. The aim of the project was to highlight in an extensive way differences in settlement layouts while investigating commonalities as a way to understand Neolithic use of space. To accomplish this, a suite of geophysical prospection techniques (geomagnetic, electromagnetic induction, and Ground Penetrating Radar (GPR)), aerial platforms (historic aerial imagery and Remotely Piloted Aerial Systems (RPAS)) as well as very high resolution spaceborne sensors were integrated to acquire comprehensive pictures of settlements. Results of the IGEAN project provide archaeological information on the dynamic character of enclosures, the structure of architectural features and open spaces within sites as an indication of economic or communal spaces. At the same time, they demonstrated the importance of employing a suite of different geophysical techniques to reveal different aspects of the hindered prehistoric settlements that could not be highlighted with a single geophysical approach. Full article

A comprehensive glacier–glacial lake inventory was developed for the Bhutan Himalayas based on satellite observations between 1987–1990 and 2006–2011. In total, 733 lakes (covering 82.6 km²) were delineated between 4000 and 6000 m a.s.l. and their relationships to associated glaciers were documented. Using this new inventory, the scale and potential for glacial lake outburst flooding (GLOF) based on multiple criteria was examined. This included a history of connectivity characteristics of glacial lakes to mother glaciers, potential flood volumes, and debris-cover of mother glaciers in addition to the conventional criteria of expansion rate and lake size. The majority of the lakes with high expansion rates (more than double in size) and large areas (>0.1 km²) met the conditions of being continuously in contact with a mother debris-covered glacier for nearly 20 years. Based on these multiple criteria, two lakes were identified as having potential for large-scale GLOF. Potentially dangerous glacial lakes listed in the International Centre for Integrated Mountain Development (ICIMOD) study were re-visited, and some overlaps with the glacier–glacial lake inventory were found. Full article

Mineral elements are essential nutrients for humans and play important roles in many human physiological and bio-chemical processes. In this study, a comparison between the levels of mineral elements present in the water of public drinking fountains (PDRF) and in bottled water was carried out. The aim of the study is to assess the effectiveness of PDRF as a mineral supplement, compared to the low-mineral bottled water for out-door non-competitive activity, such as jogging. The city of Ferrara was chosen as the study site. It has ancient walls and on their top there is a gravel road that people use for jogging and walking. Along the road, there are two public drinking fountains that are always used. Water from these fountains was sampled and analysed for major cations and anions using ionic chromatography. Data analyses were compared with the same analyses carried out on bottled water usually used by joggers. Results showed that fountains are a valid substitute of bottled water as they have a moderate content of mineral elements. During outdoor sport activity, the water from fountains is preferable for the reintegration of mineral elements, instead of bottled water that has a very low quantity of minerals. Full article

Phase equilibria modelling incorporating melt reintegration offers a methodology to create hypothetical rock compositions that may have existed prior to melt loss, allowing the potential prograde evolution of rocks to be explored. However, melt reintegration modelling relies on assumptions concerning the volume of melt that was lost and is generally restricted by the absence of direct constraints on the pre-anatectic mineral assemblages. Mg-rich granulite in the 514–490 Ma Delamerian Orogen in southern Australia contains spinel–cordierite symplectic intergrowths that surround rare, coarse blocky domains of sillimanite. These sillimanite cores, as well as the widespread presence of andalusite in lower grade areas of the southern Delamerian Orogen, suggest that the subsolidus precursor to the granulite contained andalusite. This provides the opportunity to test if melt reintegration modelling of the granulite predicts subsolidus andalusite. Stepwise down-temperature melt reintegration modelling produces a water-saturated solidus after the addition of 12 mol% melt. When modelled at subsolidus conditions, the resulting rock composition produces andalusite-bearing assemblages with andalusite modes similar to the abundance of the sillimanite-cored spinel–cordierite intergrowths. The modelling results from this case study suggest that melt reintegration modelling is a valid method to recreate prograde subsolidus bulk rock compositions. Full article

Debris loads during flood events have been well-documented by forensic engineering field surveys of affected communities. Research has primarily focused on debris impact loading and less emphasis has been placed into quantifying the loads and effects associated with debris damming, which occurs when solid objects accumulate at the front of structures. The formation of the debris dam has been shown to results in increased drag forces, backwater rise, and flow accelerations which can influence the stability of the structure. This study examined the formation of a debris dam in steady-state conditions of debris common to flood-prone communities. The study determined that the hydraulic conditions, in particular flow velocity, influenced the formation of the debris dam. Additionally, the study examined the influence of the blockage ratio on the backwater rise as well as the drag coefficient. Full article

Cua Dai is one of the major estuarine areas in Central Vietnam that plays a significant role in local maritime transport, fisheries, and tourism activities. This paper presents a study that monitored the shoreline dynamics of the Cua Dai estuary over a period of 50 years (1964–2014) by using field survey data, geographic information systems techniques, and multi-temporal satellite remote sensing images (ALOS-AVNIR2 and Landsat imageries). The assessment of shoreline changes was divided into three phases: 1964–1980, 1981–2000, and 2001–2014. The results revealed that over the last 50 years, shoreline changes dramatically occurred between 1964 and 1980. The general trends of erosion and accretion at the Cua Dai estuary show that the river mouth moved towards the south due to the erosion of shorelines in the north and the river bank in the south of the Cua Dai estuary. The study outcomes can provide essential information for planning, zoning, and sustainable development activities of the coastal zones in the context of climate change. Full article

This paper gives an overview of the large-scale tectonic styles encountered in orogens worldwide. Thin-skinned and thick-skinned tectonics represent two end member styles recognized in mountain ranges. Both styles are encountered in former passive margins of continental plates. Thick-skinned style including the entire crust and possibly the lithospheric mantle are associated with intracontinental contraction. Delamination of subducting continental crust and horizontal protrusion of upper plate crust into the opening gap occurs in the terminal stage of continent-continent collision. Continental crust thinned prior to contraction is likely to develop relatively thin thrust sheets of crystalline basement. A true thin-skinned type requires a detachment layer of sufficient thickness. Thickness of the décollement layer as well as the mechanical contrast between décollement layer and detached cover control the style of folding and thrusting within the detached cover units. In subduction-related orogens, thin- and thick-skinned deformation may occur several hundreds of kilometers from the plate contact zone. Basin inversion resulting from horizontal contraction may lead to the formation of basement uplifts by the combined reactivation of pre-existing normal faults and initiation of new reverse faults. In most orogens thick-skinned and thin-skinned structures both occur and evolve with a pattern where nappe stacking propagates outward and downward. Full article

Understanding paleo—and recent environmental changes and the dynamics of individual drivers of water availability is essential for water resources management in the Mongolian Altai. Here, we follow a holistic approach to uncover changes in glaciers, permafrost, lake levels and climate at the Tsengel Khairkhan massif. Our general approach to describe glacier and lake level changes is to combine traditional geomorphological field mapping with bathymetric measurements, satellite imagery interpretation, and GIS analyses. We also analysed climate data from two nearby stations, and measured permafrost temperature conditions at five boreholes located at different elevations. We identified four glacial moraine systems (M4-M1) and attribute them to the period from the penultimate glaciation (MIS 4/5) until the Little Ice Age (MIS 1). During the Local Last Glacial Maximum (LLGM; MIS 2), a glacier reached down into the western Kharganat Valley and blocked it, resulting in the formation of the endorheic Khar Lake basin. Subsequently, the lake was fed mainly by precipitation and permafrost meltwater. In recent years, glaciers have been in strong recession, yet Khar Lake levels have remained relatively stable, which is in contrast to mainly decreasing lake levels in other regions throughout Mongolia. While temperatures in the Altai are increasing (leading to increasing evaporation), precipitation in higher elevations has increased, which—in addition to increased glacier and permafrost melting—would counteract the increasing aridity effects. A systematic and holistic monitoring of glaciers, permafrost, lake levels and climate in the Mongolian Altai is necessary, and results from (sub-)disciplines need to be correlated. Full article

Modern scanning electron microscopes often include software that allows for the possibility of obtaining large format high-resolution image montages over areas of several square centimeters. Such montages are typically automatically acquired and stitched, comprising many thousand individual tiled images. Images, collected over a regular grid pattern, are a rich source of information on factors such as variability in porosity and distribution of mineral phases, but can be hard to visually interpret. Additional quantitative data can be accessed through the application of image analysis. We use backscattered electron (BSE) images, collected from polished thin sections of two limestone samples from the Cretaceous of Brazil, a Carboniferous limestone from Scotland, and a carbonate cemented sandstone from Northern Ireland, with up to 25,000 tiles per image, collecting numerical quantitative data on the distribution of porosity. Images were automatically collected using the FEI software Maps, batch processed by image analysis (through ImageJ), with results plotted on 2D contour plots with MATLAB. These plots numerically and visually clearly express the collected porosity data in an easily accessible form, and have application for the display of other data such as pore size, shape, grain size/shape, orientation and mineral distribution, as well as being of relevance to sandstone, mudrock and other porous media. Full article

The study investigated the basic geomechanical and mineralogical evolution of the bentonite barrier under various experimental boundary conditions which replicated the near-field Thermo-Hydro-Chemico (THC) conditions in a repository. The relationships between the physicochemical alterations and changes in the geotechnical properties have seldom been studied, especially on a consistent dataset. This paper attempts to link the physicochemical properties of Na-bentonite (MX-80) to the macro-scale engineering functionality of the bentonite post THC exposure. Experiments investigated the impact of THC variables on the engineering and physicochemical functionality of the bentonite with respect to its application within a High-Level Waste (HLW) engineered barrier system. Intrinsic alterations to the MX-80 bentonite under relatively short-term exposure to hydrothermal and chemical conditions were measured. Additionally, two long-term tests were conducted under ambient conditions to consider the impact of exposure duration. The intrinsic measurements were then related to the overall performance of the bentonite as a candidate barrier material for application in a UK geological disposal facility. Findings indicate that exposure to thermo-saline-corrosion conditions (i.e., corrosion products derived from structural grade 275 carbon steel) inhibits the free swell capacity and plasticity of the bentonite. However, the measured values remained above the design limits set out for the Swedish multi-barrier concept, from which the UK concept may take a lead. Corrosion alone does not appear to significantly affect the geotechnical measurements compared with the influence of thermal loading and high saline pore water after relatively short-term exposure. Thermal and corrosion exposure displayed no impact on the intrinsic swelling of the smectite component, indicating that no significant structural alteration had occurred. However, when exploring more complex saline solutions i.e., mixed Na, K and Ca, rather than the reference NaCl, divalent cation replacement was observed within the interlayer exchange site. This was accelerated in higher thermal loading conditions. Full article

Ultraviolet imaging has been applied in volcanology over the last ten years or so. This provides considerably higher temporal and spatial resolution volcanic gas emission rate data than available previously, enabling the volcanology community to investigate a range of far faster plume degassing processes than achievable hitherto. To date, this has covered rapid oscillations in passive degassing through conduits and lava lakes, as well as puffing and explosions, facilitating exciting connections to be made for the first time between previously rather separate sub-disciplines of volcanology. Firstly, there has been corroboration between geophysical and degassing datasets at ≈1 Hz, expediting more holistic investigations of volcanic source-process behaviour. Secondly, there has been the combination of surface observations of gas release with fluid dynamic models (numerical, mathematical, and laboratory) for gas flow in conduits, in attempts to link subterranean driving flow processes to surface activity types. There has also been considerable research and development concerning the technique itself, covering error analysis and most recently the adaptation of smartphone sensors for this application, to deliver gas fluxes at a significantly lower instrumental price point than possible previously. At this decadal juncture in the application of UV imaging in volcanology, this article provides an overview of what has been achieved to date as well as a forward look to possible future research directions. Full article

A detailed study had been conducted on the sediment of Mount Samalas’ volcanic eruption in 1257 AD. Using the framework of the reconstruction of the ancient eruption of Mount Samalas, the first step was to map and analyze the deposits of volcanic sediment. Secondly, we analyzed the effect of geomorphology and the distance function to the isopach thickness. The results show that a combination of methods allowed to provide a high resolution map of the distribution of the thickness of the volcanic deposits, both on the slope and in alluvial areas. Geo-electric survey results (both Vertical Electric Sound (VES) and 2D mapping) show consistent changes in the pattern of contrast resistivity layer interface, for all areas. The pattern changes in a row of the top layer, the high resistivity turned into the low. Furthermore, the second and third layer interface changes from low to the high resistivity. High resistivity on the top layer is interpreted as a layer of unconsolidated volcanic sediment. High resistivity values are range from 736 to 2000 Ohm.m on the top layer in the area of the slopes while in the area of alluvial, the resistivity values range from 20 to 958 Ohm.m. Generally, the volcanic deposits in the area of the slopes have a higher value of isopach (>17 m) than in areas of alluvial (<25 m). The geomorphology seemed to have no significant effect on the isopach value, particularly pyroclastic fallout. Such is the case with distance from the source to the site, which is not linear. The value of isopach increases westward from 21 to 31 km, in contrast to the East, which began to occur at a distance of 14 km to 21 km. Full article

Detailed field mapping of glacial and paraglacial landforms and optical dating from these landforms are used to reconstruct the early Holocene glaciation in the semi-arid region of Miyar basin, Lahaul Himalaya. The study identifies three stages of glaciation, of decreasing magnitude and termed, from oldest to youngest, the Miyar stage (MR-I), Khanjar stage (KH-II), and Menthosa advance (M-III). The oldest glacial stage (MR-I) has been established on the basis of detailed geomorphological evidence such as U-shaped valley morphology, trimlines, and truncated spurs. It is speculated to be older than the global Last Glacial Maximum (gLGM) based on the magnitude of ΔELA (Equilibrium-Line Altitude, 606m). No evidence of glacier expansion recorded from the basin correlates with the period of the gLGM. The second stage (KH-II) is well represented by extensive depositional features such as lateral and terminal moraines, drumlins, and lacustrine fills that have been constrained within 10 ± 1 to 6.6 ± 1.0 ka (Optically stimulated luminescence—OSL—ages), dating it to the early Holocene advance following the Younger Dryas cooling event. Exceptionally young glacial records of expansion are limited within a few hundred meters of the present termini of tributary glaciers and correlates with the 18th-century cooling event. Records of this glacial advance, termed the Menthosa advance, are clearly noticed in some tributary valleys. Full article

The Citarum River has a volcanic catchment area in West Java Province, and is one of the nationally strategic rivers in tropical Indonesia due to its roles in water supply and in power generation. The river is economically important, but it is also polluted by industrial, agricultural, and residential wastes. Suspended sediment samples were collected along a certain section of the Citarum River, starting in Balekambang through the area of Bandung Regency to the downstream village of Nanjung, where the river is dammed. Similar samples were also collected from seven tributaries of the Citarum River. Magnetic and heavy metal analyses show that unlike river sediments from a non-volcanic catchment area in temperate climates, magnetic susceptibility values tend to decrease downstream, showing that the magnetic minerals in the upstream area are mostly lithogenic in origin, containing more Fe-bearing minerals compared to those in tributary samples which are anthropogenic in origin. Anthropogenic pollution is also represented by the increase of Zn content along the river. The results suggest that applying magnetic methods for monitoring river pollution in the tropics or in the volcanic areas should be carefully analyzed and interpreted. Full article

Freezing and thawing of the land surface affects ecosystem and hydrological processes, the geotechnical properties of soil and slope stability. Currently, available datasets on land surface state lack either sufficient temporal or spatial resolution to adequately characterize the complexity of freeze/thaw transition period dynamics. Surface state changes can be detected using microwave remote sensing methods. Data available from scatterometer and Synthetic Aperture Radar (SAR) sensors have been used in the past in regional- to continental-scale approaches to monitor freeze/thaw transitions. This study aims to identify temporal and spatial patterns in freeze/thaw dynamics associated with the issue of differing temporal and spatial resolutions. For this purpose, two datasets representing the timing of freeze/thaw cycles at different resolutions and spatial extents were chosen. The used Advanced SCATterometer (ASCAT) Surface State Product offers daily circumpolar information from 2007–2013 for a 12.5-km grid. The SAR freeze/thaw product offers information of day of thawing and freezing for the years 2005–2010 with a nominal resolution of 500 m and a temporal resolution of up to twice per week. In order to assess the importance of scale when describing temporal and spatial patterns of freeze/thaw processes, the two datasets were compared for spring and autumn periods for the maximum number of overlapping years 2007–2010. The analysis revealed non-linear landscape specific relationships between the two scales, as well as distinct differences between the results for thawing and re-freezing periods. The results suggest that the integration of globally available high temporal resolution scatterometer data and higher spatial resolution SAR data could be a promising step towards monitoring surface state changes on a seasonal, as well as daily and circumpolar, as well as local scale. Full article

Volcanic ash is a volcanic product with a wide distribution that can be used as a geological marker. In volcanic regions such as Indonesia, the identification of the sources of volcanic ash and tuff layers from different volcanoes or eruptive events is a challenging task. In this study, samples of volcanic ash from the 2010 eruption of Bromo—a relatively young and active tuff cone volcano within the Sandsea caldera in the Tengger volcanic complex in East Java, Indonesia—along with two older tuff layers from the same caldera (Widodaren tuff: 1.8 kyr and Segarawedi tuff: 33 kyr) were subjected to magnetic measurements, geochemical analyses, and petrographic analyses. The aim is to attempt to use magnetic characters as a fingerprint for volcanic ash and tuff layers. The results show that the samples had variations in grain size and magnetic domain as indicated by the hysteresis parameters. These magnetic characters correlated with the results of geochemical and petrographic analyses, suggesting that magnetic properties may potentially be used as fingerprints to identify volcanic ashes and tuff layers. Full article

It is inevitable to find in studies that shoreline position extracted from unknown capture time aerial photograph or satellite image was not corrected to tidal effect. In this study, an approach is introduced that can estimate the capture time of image from the solar azimuth angle and the length of shadow of a vertical object on the horizontal surface on the earth. The capture time of tze aerial photograph estimated from solar azimuth angle has a much smaller deviation than the one estimated from the length of the shadow. This error is acceptable for tidal correction purposes. The approach was also utilized to estimate the capture time of a set of satellite images on Sendai coast. Therefore, the tidal correction was implemented for shoreline positions extracted from those images. Full article