EUROVOLC Virtual Access to computational tools at INGV Pisa

2020 ◽  
Author(s):  
Mattia de’ Michieli Vitturi ◽  
Francesco Martinelli ◽  
Matteo Cerminara ◽  
Chiara Paola Montagna ◽  
Tomaso Esposti Ongaro ◽  
...  
Keyword(s):  
Volcanic Eruptions ◽  
Intermediate Level ◽  
Magma Ascent ◽  
Large Set ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Computational Tools ◽  
Web Based ◽  
Kinematic Modelling ◽  
Increasing Demand

<p>While computational capabilities in volcano science are developing to progressively higher sophistication levels involving HPC, parallel programming, and extensive use of super-computers, there is an increasing demand for accessibility to low to intermediate-level models and codes that can support multi-disciplinary research carried out by experts other than physical modelers and code developers. Responding to such a need by the international community is the justification and objective of Virtual Access (VA) activities developed under the EUROVOLC project. The Volcano Dynamics Computational Centre (VDCC) at INGV Pisa is renown as one international leader in physical-mathematical modelling and numerical simulation of volcanic thermo-fluid dynamics processes occurring from the deep regions of magma rise and accumulation within the crust, to within the atmosphere during volcanic eruptions. VDCC has been developing a large set of computational tools during last 30 years, that are offered under EUROVOLC for Transnational Access (for the most sophisticated, computational demanding models and codes) as well as for VA for low to intermediate-level models and codes. The latter include from non-ideal, compositional-dependent, multi-component volatile-melt thermodynamics to steady-state magma ascent to fast-performing kinematic modelling of pyroclastic density currents. Here we illustrate the model capabilities, the procedures to both download the codes and perform web-based computation, and a few relevant examples of calculations available through VA, and show relevant statistics of access and download by the volcano community to-date.</p>

Web-based Tools for Drug Repurposing: Successful Examples of Collaborative Research

2020 ◽  
Vol 28 (1) ◽  
pp. 181-195
Author(s):  
Quentin Vanhaelen
Keyword(s):  
User Interfaces ◽  
Collaborative Research ◽  
Meta Analysis ◽  
A Priori ◽  
Drug Repurposing ◽  
Data Access ◽  
Estimation Methods ◽  
Large Set ◽  
Computational Tools ◽  
Web Based

: Computational approaches have been proven to be complementary tools of interest in identifying potential candidates for drug repurposing. However, although the methods developed so far offer interesting opportunities and could contribute to solving issues faced by the pharmaceutical sector, they also come with their constraints. Indeed, specific challenges ranging from data access, standardization and integration to the implementation of reliable and coherent validation methods must be addressed to allow systematic use at a larger scale. In this mini-review, we cover computational tools recently developed for addressing some of these challenges. This includes specific databases providing accessibility to a large set of curated data with standardized annotations, web-based tools integrating flexible user interfaces to perform fast computational repurposing experiments and standardized datasets specifically annotated and balanced for validating new computational drug repurposing methods. Interestingly, these new databases combined with the increasing number of information about the outcomes of drug repurposing studies can be used to perform a meta-analysis to identify key properties associated with successful drug repurposing cases. This information could further be used to design estimation methods to compute a priori assessment of the repurposing possibilities.

The muesli effect in pyroclastic density currents - what does reverse grading in an ignimbrite mean? 

2021 ◽  
Author(s):  
Matthew Johnson ◽  
Natasha Dowey ◽  
Rebecca Williams ◽  
Pete Rowley
Keyword(s):  
Volcanic Eruptions ◽  
Volcanic Hazards ◽  
Transport Processes ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Static Tests ◽  
Grain Sizes ◽  
Unidirectional Flow ◽  
3D Architecture ◽  
The Relationship

<p>Pyroclastic density currents (PDCs) are hot, density-driven flows of gas, rock and ash generated during explosive volcanic eruptions, or from the collapse of lava domes (e.g. Fisher, 1979; Branney and Kokelaar, 2002; Cas et al. 2011). They pose a catastrophic geological hazard and have caused >90 000 deaths since 1600AD (Auker et al. 2013). Improved understanding of PDCs will enable us to better understand the explosive eruptions that generate them, improving our preparedness for future volcanic events. However, these deadly hazards are rarely observed up close and are difficult to analyse in real-time. To understand the flow dynamics of density currents we must use models and interpretations of their deposits (e.g. Smith N and Kokelaar, 2013; Rowley et al. 2014, Williams et al. 2014, Sulpizio et al. 2014; Lube et al. 2019, Smith G 2018, 2020).</p><p>The deposits of pyroclastic density currents, known as ‘ignimbrites’ can reveal important clues about how these deadly volcanic hazards behave in time and space Reverse grading in an ignimbrite can be interpreted in different ways (Branney & Kokelaar, 2002). It could record a growing eruption intensity through time - where increasingly larger clasts are introduced into the pyroclastic density current. Alternatively, it could record Kinematic sorting (the ‘muesli effect’) and transport processes within the current where larger particles became increasingly likely to be deposited as the current wanes (Palladino & Valentine,1995). The link between current dynamics and reverse grading is currently untested in aerated granular currents.</p><p>This project seeks to investigate the relationship between current dynamics and deposit architecture, specifically by considering granular sorting mechanisms in unidirectional flow. We will use an analogue flume (following methods in Rowley et. al., 2014, and Smith G et al., 2018, 2020) to explore how reverse grading and lateral grading may be related to changes in grain sizes at source versus kinematic sorting processes. A mix of grain sizes will be incorporated into the current via a hopper which allows for the starting composition of the current to be varied e.g. homogenous mix versus layered. Photographs of the deposit will be taken through the transparent sidewall of the flume and analysed using image analysis software. These experiments will be complimented by static tests of kinematic sorting, where a Perspex column will be sliced to reveal internal 3d architecture. This project will contribute to our understanding of lithofacies architecture in the field, and help to quantity how we interpret the sedimentation of ignimbrites.</p><p><em>References</em></p><p>Auker et al. (2013) https://doi.org/10.1186/2191-5040-2-2</p><p>Branney and Kokelaar (2002) https://doi.org/10.1144/GSL.MEM.2003.027</p><p>Cas et al. (2011) Bulletin of Volcanology 731583 https://doi.org/10.1007/s00445-011-0564-y</p><p>Fisher (1979) https://doi.org/10.1016/0377- 0273(79)90008-8    </p><p>Lube et al. (2019) https://doi.org/10.1038/s41561-019-0338-2</p><p>Palladino & Valentine (1995). https://doi.org/10.1016/0377-0273(95)00036-4</p><p>Rowley et al. (2014) https://doi.org/10.1007/s00445-014-0855-1</p><p>Smith N. and Kokelaar (2013) https://doi.org/10.1007/s00445-013-0768-4</p><p>Smith G. et al. (2018) https://doi.org/10.1007/s00445-018-1241-1</p><p>Smith, G. et al. (2020). https://doi.org/10.1038/s41467-020-16657-z</p>

Experimental constraints on volcanic ash generation and clast morphometrics in pyroclastic density currents and granular flows

2021 ◽  
Author(s):  
Adrian Hornby ◽  
Ulrich Kueppers ◽  
Benedikt Maurer ◽  
Carina Poetsch ◽  
Donald Dingwell
Keyword(s):  
Experimental Approach ◽  
Direct Evidence ◽  
General Description ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Shape Factors ◽  
Material Density ◽  
Bed Height ◽  
Rotary Drum ◽  
Basal Flow

<p>Pyroclastic density currents (PDCs) present perhaps the greatest proximal primary hazard of volcanic activity and produce abundant fine ash that can present a range of health, environment and infrastructure hazards. However, direct, fully quantitative observation of ash production in PDCs is lacking, and little direct evidence exists to constrain the parameters controlling ash generation in PDCs. Here, we use an experimental approach to investigate the effects of starting mass, material density and ash removal on the efficiency of ash generation and concurrent clast rounding in the dense basal flow of PDCs. We employ a rotary drum to tumble pumice and scoria lapilli clasts over multiple transport “distance” steps (from 0.2 to 6 km). We observe increased ash generation rates with the periodic removal of ash during the experiments and with increasing starting mass. By scaling to the bed height and clast diameter we obtain a general description for ash production in all experiments as a function of flow distance, bed height and average clast diameter. We confirm that changes in lapilli shape factors correlate with the ash fraction generated and that the grain size of ash produced decreases with distance. Finally, we estimate shear rate in our experiments and calculate the inertial number, which describes the ratio between clast-scale and flow-scale rearrangement during flow. We show that, under certain conditions, fractional ash production can be calculated accurately for any starting mass solely as a function of the inertial number and the flow distance. This work sheds light on some of the first systematic and generalizable experimental parameterizations of ash production and associated clast evolution in PDCs and should advance our ability to understand flow mobility and associated hazards.</p>

The numerical reconstruction of three past eruptions at Gede volcano (Indonesia)

2021 ◽  
Author(s):  
Eleanor Tennant ◽  
Susanna Jenkins ◽  
Annie Winson ◽  
Christina Widiwijayanti ◽  
Hendra Gunawan ◽  
...  
Keyword(s):  
Epistemic Uncertainty ◽  
Source Parameters ◽  
Frictional Resistance ◽  
Collapse Mechanism ◽  
Eruption Dynamics ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Basal Friction ◽  
Column Collapse ◽  
Hazard And Risk

<p>Understanding past eruption dynamics at a volcano is crucial for forecasting the range of possible future eruptions and their associated hazards and risk. In this work we reconstructed pyroclastic density currents and tephra fall from three eruptions at Gede volcano, Indonesia with the aim of gaining further insight into past eruptions and identifying suitable eruption source parameters for future hazard and risk assessment. Gede has the largest number of people living within 100 km of any volcano worldwide, and has exhibited recent unrest activity, yet little is known about its eruption history. For pyroclastic density currents, we used Titan2D to reconstruct geological deposits dated at 1200 and c. 1000 years BP. An objective and quantitative multi-criteria method was developed to evaluate the fit of over 300 pyroclastic density current (PDC) model simulations to field observations. We found that the 1200 years BP geological deposits could be reproduced with either a dome collapse or column collapse as the generation mechanism although a relatively low basal friction of 6 degrees would suggest that the PDCs were markedly mobile. Lower basal frictions may reflect the occurrence of previous PDCs that smoothed the path, reducing frictional resistance and enabling greater runout for the reconstructed unit. For the 1,000 years BP PDC, a column collapse mechanism and higher basal friction was required to fit the geological deposits. In agreement with previous studies, we found that Titan2D simulations were most sensitive to the basal friction; however, we also found that the internal friction – often fixed and considered of low influence on outputs - can have a moderate effect on the simulated average deposit thickness. We used Tephra2 to reconstruct historic observations of tephra dispersed to Jakarta and other towns during the last known magmatic eruption of Gede in 1948. In the absence of observable field deposits, or detailed information from the published literature, we stochastically sampled eruption source parameters from wide ranges informed by analogous volcanic systems. Our modelling suggests that the deposition of tephra in Jakarta during the November 1948 eruption was a very low probability event, with approximately a 0.03 % chance of occurrence. Through this work, we exemplify the reconstruction of past eruptions when faced with epistemic uncertainty, and improve our understanding of past eruption dynamics at Gede volcano, providing a crucial step towards the reduction of risk to nearby populations through volcanic hazard assessment.</p>

scholarly journals The hazards of unconfined pyroclastic density currents: a new synthesis and classification according to their deposits, dynamics, and thermal and impact characteristics

2021 ◽  
Author(s):  
Geoffrey Lerner ◽  
Susanna Jenkins ◽  
Sylvain Charbonnier ◽  
Jean-Christophe Komorowski ◽  
Peter Baxter
Keyword(s):  
Volcanic Hazards ◽  
High Energy ◽  
Significant Loss ◽  
Lessons Learned ◽  
Pyroclastic Density Currents ◽  
Density Currents ◽  
Loss Of Life ◽  
New Synthesis ◽  
End Members ◽  
Impact Characteristics

Pyroclastic density currents (PDCs) that escape their confining channels are among the most dangerous of volcanic hazards. These unconfined PDCs are capable of inundating inhabited areas that may be unprepared for these hazards, resulting in significant loss of life and damage to infrastructure. Despite their ability to cause serious impacts, unconfined PDCs have previously only been described for a limited number of specific case studies. Here, we carry out a broader comparative study that reviews the different types of unconfined PDCs, their deposits, dynamics and impacts, as well as the relationships between each element. Unconfined PDCs exist within a range of concentration, velocity and temperature: characteristics that are important in determining their impact. We define four end-member unconfined PDCs: 1. fast overspill flows, 2. slow overspill flows, 3. high-energy surges, and 4. low-energy detached surges (LEDS), and review characteristics and incidents of each from historical eruptions. These four end-members were all observed within the 2010 eruptive sequence of Merapi, Indonesia. We use this well-studied eruption as a case study, in particular the villages of Bakalan, 13 km south, and Bronggang 14 km south of the volcano, which were impacted by slow overspill flows and LEDS, respectively. These two unconfined PDC types are the least described from previous eruptions, but during the Merapi eruption the overspill flow resulted in building destruction and the LEDS in significant loss of life. We discuss the dynamics and deposits of these unconfined PDCs, and the resultant impacts. We then use the lessons learned from the 2010 Merapi eruption to assess some of the impacts associated with the deadly 2018 Fuego, Guatemala eruption. Satellite imagery and media images supplementing fieldwork were used to determine the presence of both overspill flows and LEDS, which resulted in the loss of hundreds of lives and the destruction of hundreds of buildings in inundated areas within 9 km of the summit. By cataloguing unconfined PDC characteristics, dynamics and impacts, we aim to highlight the importance and value of accounting for such phenomena in emergency management and planning at active volcanoes.

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