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Stationary antidunes are a product of critical flow in open channel systems, but with poor preservation potential. They are related to the existence of stationary surface waves in the overriding current, but their existence in the dense pyroclastic density current regime has been unrecognized to date. Experiments presented here demonstrate that surface waves in simulated dense pyroclastic density currents show both supercritical downstream-migrating and critical stationary wave behaviour. Deposits from the Pozzolane Rosse ignimbrite (Italy) demonstrate the presence of stationary wave antidunes in deposits from dense pyroclastic currents which imply progressive aggradation from long-lived quasi-stable critical flow conditions during their emplacement. The narrow stability fields for the formation of these deposits reinforces that they are unlikely to be widely preserved in the geological record, but highlights that dense pyroclastic density currents cannot be assumed to be simply supercritical flows, and they may be substantially slower than over-riding dilute currents.

This review summarizes what the volcanology community has learned thus far from studying the deposits of pyroclastic currents (PCs) from the 1980 eruption sequence at Mount St. Helens. The review includes mass flow events during the May 18 eruption, including the lateral blast, the afternoon column collapse and boil-over PC activity, and some aspects of the debris avalanche. We also include a summary of PCs generated in the smaller eruptions following the climactic May 18 event. Our objective is to summarize the state of our understanding of PC transport and emplacement mechanisms from the combination of field and laboratory observations, granular flow experiments, and numerical modeling techniques. Specifically, we couple deposit characteristics, experiments, and numerical modeling techniques to critically address the problems of (1) constraining conditions in the flow boundary zone at the time of deposition; (2) the influence of substrate roughness and topography on PC behavior; (3) the prevalence, causes, and consequences of substrate erosion by PCs; and (4) the reconstruction of PC transportation and sedimentation processes from a combination of geophysical and sedimentological observations. We conclude by providing opportunities for future research as our field, experimental, and numerical research techniques advance.

In this paper we reply to the criticisms advanced by Narkiewicz (2017) on the paper by Schito et al. (2017). We clarify the issues related to the stratigraphic and thermal maturity constraints used for reconstructing burial and thermal models of the two blocks of the Holy Cross Mountains. We also show how geological evidences brought by Narkiewicz (2017) as a proof of elevated Variscan heat flow are not conclusive or at least suggest the occurence of a localized thermal anomaly only along the area of the Holy Cross Fault. In the end, we performed new burial and thermal models in the Kielce region demonstrating that stratigraphic thickness variations between Schito et al. (2017) and Narkiewicz et al. (2010) produce only negligible differences in levels of thermal maturity of Paleozoic rocks. In addition, we outline that levels of thermal maturity for Silurian rocks can be matched only by using constant heat flow values through the Paleozoic and point to a decisive role for the absence of regional high Variscan heat flow in the area.

Limited information is available on suitable height of transport crates for turkeys. We compared behaviors and physiological indicators of four groups of 10 female turkeys each confined in either conventional (38.5 cm height) or experimental (77 cm height) crates during six commercial pre-slaughter transportations for 86 km (76 ± 4 min) along two tracts with one-lane streets, crossroads, bends, roundabouts (S1 and S2) and a highway tract (H) between S1 and S2. Only 36% of birds in the higher crates maintained a standing position. In conventional versus experimental crates, the frequency of rising attempts was five/bird/hour versus less than one/bird/hour, while wing flapping was seven/bird/hour versus 20/bird/hour, and balance loss was one versus four/bird/hour. The behaviors of both groups differed significantly according to the route tract, with a lower frequency of stress-related behaviors at H. No scratches, fractures or hematomas were detected in any birds after transportation. Crate height had no significant effect on hemato-biochemical markers. These results suggest that crates enabling a standing position may increase potentially dangerous behaviors. Moreover, busy and curvy routes should be avoided, as they may contribute to increasing the frequency of stress-related behaviors.

Pyroclastic density currents (PDCs) are a life-threatening volcanic hazard. Our understanding and hazard assessments of these flows rely on interpretations of their deposits. The occurrence of stratified layers, cross-stratification, and bedforms in these deposits has been assumed as indicative of dilute, turbulent, supercritical flows causing traction-dominated deposition. Here we show, through analogue experiments, that a variety of bedforms can be produced by denser, aerated, granular currents, including backset bedforms that are formed in waning flows by an upstream-propagating granular bore. We are able to, for the first time, define phase fields for the formation of bedforms in PDC deposits. We examine how our findings impact the understanding of bedform features in outcrop, using the example of the Pozzolane Rosse ignimbrite of the Colli Albani volcano, Italy, and thus highlight that interpretations of the formative mechanisms of these features observed in the field must be reconsidered., In this study, Smith and colleagues employ analogue experiments to show the controlling parameters on sediment bedforms in pyroclastic density current deposits. The findings are applied and validated on natural deposits.

The gravitational collapse of eruption columns generates ground-hugging pyroclastic density currents (PDCs) with highly variable temperatures, high enough to be a threat for communities surrounding volcanoes. The reasons for such great temperature variability are debated in terms of eruptive versus transport and emplacement processes. Here, using a three-dimensional multiphase model, we show that the initial temperature of PDCs linearly correlates to the percentage of collapsing mass, with a maximum temperature decrease of 45% in the case of low percentages of collapse (10%), owing to an efficient entrainment of air into the jet structure. Analyses also demonstrate that column collapse limits the dispersal capabilities of volcanic plumes, reducing their maximum height by up to 45%. Our findings provide quantitative insights into the mechanism of turbulent mixing, and suggest that temperatures of PDC deposits may serve as a marker for determining column collapse conditions, which are of primarily importance in hazard studies., Pyroclastic density currents (PDCs) are a major threat during explosive volcanic eruptions, hence the possibility to forecast them would be a vital improvement for risk mitigation. Here the authors present a 3D flow model to quantify the thermal patterns leading to volcanic ash plume collapse conditions.

Pyroclastic density currents (PDCs) can have devastating impacts on urban settlements, due to their dynamic pressure and high temperatures. Our degree of understanding of the interplay between these hot currents and the affected infrastructures is thus fundamental not only to implement our strategies for risk reduction, but also to better understand PDC dynamics. We studied the temperature of emplacement of PDC deposits that destroyed and buried the Villa dei Papiri, an aristocratic Roman edifice located just outside the Herculaneum city, during the AD79 plinian eruption of Mt Vesuvius (Italy) by using the thermal remanent magnetization of embedded lithic clasts. The PDC deposits around and inside the Villa show substantial internal thermal disequilibrium. In areas affected by convective mixing with surface water or with collapsed walls, temperatures average at around 270 °C (min 190 °C, max 300 °C). Where the deposits show no evidence of mixing with external material, the temperature is much higher, averaging at 350 °C (min 300 °C; max 440 °C). Numerical simulations and comparison with temperatures retrieved at the very same sites from the reflectance of charcoal fragments indicate that such thermal disequilibrium can be maintained inside the PDC deposit for time-scales well over 24 hours, i.e. the acquisition time of deposit temperatures for common proxies. We reconstructed in detail the history of the progressive destruction and burial of Villa dei Papiri and infer that the rather homogeneous highest deposit temperatures (average 350 °C) were carried by the ash-sized fraction in thermal equilibrium with the fluid phase of the incoming PDCs. These temperatures can be lowered on short time- (less than hours) and length-scales (meters to tens of meters) only where convective mixing with external materials or fluids occurs. By contrast, where the Villa walls remained standing the thermal exchange was only conductive and very slow, i.e. negligible at 50 cm distance from contact after 24 hours. We then argue that the state of conservation of materials buried by PDC deposits largely depends on the style of the thermal interactions. Here we also suggest that PDC deposit temperatures are excellent proxies for the temperatures of basal parts of PDCs close to their depositional boundary layer. This general conclusion stresses the importance of mapping of deposit temperatures for the understanding of thermal processes associated with PDC flow dynamics and during their interaction with the affected environment.

Understanding the thermal behavior of pyroclastic density currents (PDCs) is crucial for forecasting impact scenarios for exposed populations as it affects their lethality and destructiveness. Here we report the emplacement temperatures of PDC deposits produced during the paroxysmal explosive eruption of Merapi (Central Java) on 5 November 2010 based on the reflectance of entombed charcoal fragments. This event was anomalously explosive for Merapi, and destroyed the summit dome that had been rapidly growing, with partial collapses and associated PDCs, since October 26. Results show mean reflectance values mainly between 0.17 and 0.41. These new data provide a minimum temperature of the flow of 240–320 °C, consistent with previous estimations determined from independent field, engineering, and medical observations published in the literature for this eruption. A few charcoal fragments recorded higher values, suggestive of temperatures up to 450 °C, and we suggest that this is due to the thermal disequilibrium of the deposits, with larger block-size clasts being much hotter than the surrounding ash matrix. Charring temperatures show no major differences between proximal and distal PDC deposits and are significantly lower than those that may be associated with a fast growing dome dominated by dense and vitric non-vesicular rocks. We therefore infer that the decrease in temperature from that at fragmentation (>900 °C) occurred in the very initial part of the current

Poland is considered the most prospective country for shale gas production in Europe. Hydrocarbon generation/expulsion scenarios, drawn in the latest intensive exploration phases, tend to overestimate maturation levels when compared with brand new data acquired after recent drillings. We tested an integrated workflow to correlate published and original thermal maturity datasets for the Paleozoic to Jurassic successions cropping out in the Holy Cross Mountains. These successions, when preserved in subsurface, host the major source rocks in the area. The application of the workflow allowed us to highlight the burial and thermal evolutionary scenarios of the two tectono-stratigraphic blocks of the Holy Cross Mountains (Łysogory and Kielce blocks) and to propose this approach as a tool for reducing levels of uncertainty in thermal maturity assessment of Paleozoic successions worldwide. In particular, published datasets including colour alteration indexes of Paleozoic microfossils (conodont, acritarchs) and vitrinite and graptolite reflectance data, show differences in levels of thermal maturity for the Łysogory (mid mature to overmature) and Kielce (immature to late mature) blocks. Original data, derived from optical analysis, pyrolysis, and Raman spectroscopy on kerogen, and X-Ray diffraction on fine-grained sediments, mostly confirm and integrate published data distribution. 1D thermal models, constrained by these data, show burial and exhumation events of different magnitude, during the Late Cretaceous, for the Łysogory (maximum burial depths of 9 km) and Kielce (burial depths of 6 km) blocks that have been related to the Holy Cross Fault polyphase activity. In the end, Palynomorph Darkness Index and Raman spectroscopy on kerogen, for Llandoverian and Cambrian rocks, turned out to be promising tools for assessing thermal maturity of Paleozoic organic facies devoid of vitrinite macerals.

Fox rabies re-emerged in north-eastern Italy at the end of 2008 and circulated until early 2011. As with previous rabies epidemics, the Italian cases were linked to the epidemiological situation in adjacent regions. To obtain a comprehensive picture of the dynamics of the recent Italian epidemic, we performed a detailed evolutionary analysis of RABVs circulating in north-eastern Italy. Sequences were obtained for the hyper-variable region of the nucleoprotein gene, the complete glycoprotein gene, and the intergenic region G-L from 113 selected fox rabies cases. We identified two viral genetic groups, here referred to as Italy-1 and Italy-2. Phylogenetic and phylogeographic analyses revealed that both groups had been circulating in the Western Balkans and Slovenia in previous years and were only later introduced into Italy (into the Friuli Venezia Giulia region-FVG), occupying different areas of the Italian territories. Notably, viruses belonging to the Italy-1 group remained confined to the region of introduction and their spread was minimised by the implementation of oral fox vaccination campaigns. In contrast, Italy-2 viruses spread westward over a territory of 100 km from their first identification in FVG, likely crossing the northern territories where surveillance was inadequate. A genetic sub-group (Italy-2A), characterised by a unique amino acid mutation (D106A) in the N gene, was also observed to occupy a distinct geographic cluster. This molecular epidemiological analysis of the 2008–2011 fox rabies epidemic will contribute to future control programmes both at national and regional levels. In particular, our findings highlight the weaknesses of the national surveillance strategy in the period preceding rabies re-emergence, and of control plans implemented immediately after rabies notification, and underline the need of a coordinated approach at the regional level for both the surveillance and control of wildlife rabies.

This paper illustrates and discusses the key issues of the geographical information system (GIS) developed by the Unit of Veterinary Epidemiology of the Veneto region (CREV), defined according to user needs, spatial data (availability, accessibility and applicability), development, technical aspects, inter-institutional relationships, constraints and policies. GeoCREV, the support system for decision-making, was designed to integrate geographic information and veterinary laboratory data with the main aim to develop a sub-national, spatial data infrastructure (SDI) for the veterinary services of the Veneto region in north-eastern Italy. Its implementation required (i) collection of data and information; (ii) building a geodatabase; and (iii) development of a WebGIS application. Tools for the management, collection, validation and dissemination of the results (public access and limited access) were developed. The modular concept facilitates the updating and development of the system according to user needs and data availability. The GIS management practices that were followed to develop the system are outlined, followed by a detailed discussion of the key elements of the GIS implementation process (data model, technical aspects, inter-institutional relationship, user dimension and institutional framework). Problems encountered in organising the non-spatial data and the future work directions are also described.