Volcanic Scenarios Research Articles

Alkali activated materials from Tajogaite volcanic ash (La Palma, Spain): a green recovery after the 2021 eruption

The 2021 Tajogaite eruption was marked by intense pyroclastic fallout that covered a substantial portion of La Palma island, with maximum thicknesses in the central-western part. This, combined with lava flows, resulted in widespread damage to public and private properties. In this study, we investigated if volcanic ash from this eruption could serve as a raw material in the synthesis of alkali activated materials (AAMs) and contribute to the construction of eco-friendly buildings and the restoration of those damaged by the eruption. Volcanic ash-based AAMs were synthesized using NaOH and Na2SiO3 as alkaline solutions and by adding metakaolin to enhance ash reactivity and enable processing at ambient temperatures. Lightweight porous AAMs were also produced using H2O2 and metallic aluminum as foaming agents. Chemical, textural, physical, and mechanical analyses on the final products assessed their suitability as environmentally friendly materials to be used in the reconstruction of the island infrastructure, opening new perspectives on recovery actions that can be undertaken after disastrous eruptions. Of all the islands in the Canary Archipelago, La Palma has experienced the highest number of eruptions (8) in historical times, all of which showing considerable similarity in terms of eruptive mechanisms and composition to the most recent Tajogaite event. Although this study investigated fresh Tajogaite ash, similar perspectives can be envisaged for both other recent eruptions at La Palma and other similar volcanic scenarios worldwide.

Universal machine learning approach to volcanic eruption forecasting using seismic features

Introduction: Volcano seismology has successfully predicted several eruptions and includes many reliable methods that have been adopted extensively by volcanic observatories; however, there are several problems that still lack solutions. Meanwhile, the overwhelming success of data-driven models to solve predictive complex real-world problems positions them as an effective addition to the monitoring systems deployed in volcanological observatories.Methods: By applying signal processing techniques on seismic records, we extracted four different seismic features, which usually change their trend when the system is approaching an eruptive episode. We built a temporal matrix with these parameters then defined a label for each temporal moment according to the real state of the volcanic activity (Unrest, Pre-Eruptive, Eruptive). To solve the remaining problem developing early warning systems that are transferable between volcanoes, we applied our methodology to databases associated with different volcanic systems, including data from both explosive and effusive episodes, recorded at several volcanic scenarios with open and closed conduits: Mt. Etna, Bezymianny, Volcán de Colima, Mount St. Helens and Augustine.Results and Discussion: This work proposes the use of Neural Networks to classify the volcanic state of alert based on the behaviour of these features, providing a probability of having an eruption. This approach offers a Machine Learning tool for probabilistic short-term volcanic eruption forecasting, transferable to different volcanic systems. This innovative method classifies the state of volcanic hazard in near real-time and estimates a probability of the occurrence of an eruption, resulting in a period from at least hours to several days to forecast an eruption.

Defect-Engineered Charge Transfer in a PtCu/PrxCe1-xO2 Carbon-Free Catalyst for Promoting the Methanol Oxidation and Oxygen Reduction Reactions.

Platinum (Pt) and Pt-based alloys have been extensively studied as efficient catalysts for both the anode and cathode of direct methanol fuel cells (DMFC). Defect engineering has been revealed to be practicable in tuning the charge transfer between Pt and transition metals/supports, which leads to the charge density rearrangement and facilitates the electrocatalytic performance. Herein, Pr-doped CeO2 nanocubes were used as the noncarbon support of a PtCu catalyst. The concentration and structure of oxygen vacancy (Vo) defects were engineered by Pr doping. Besides the Vo monomer, the oxygen vacancy with a linear structure is also observed, leading to the one-dimensional PtCu. The Vo concentration shows the volcanic scenario as Pr increased. Accordingly, the activities of PtCu/PrxCe1-xO2 toward methanol oxidation and oxygen reduction reactions exhibit the volcanic scenario. PtCu/Pr0.15Ce0.85O2 exhibits the optimal catalytic performance with the specific activity 3.57 times higher than that of Pt/C toward MOR and 1.34 times higher toward ORR. The MOR and ORR mass activities of PtCu/Pr0.15Ce0.85O2 reached 1.05 and 0.12 A·mg-1, which are 3.09 and 0.92 times the values of Pt/C, respectively. The abundant Vo afforded surplus electrons, which tailored the electron transfer between PtCu and PrxCe1-xO2, leading to enhanced catalytic performance of PtCu/PrxCe1-xO2. DFT calculations on PtCu/Pr0.15Ce0.85O2 revealed that Pr doping reduced the band gap of CeO2 and lowered the overpotential.

The Colíder Paleoproterozoic felsic volcanism: New insights into stratigraphy and petrogenesis in the southern Amazonian Craton

The eastern side of Alta Floresta Mineral Province (AFMP) (União do Norte region) comprises an effusive/subvolcanic phase, explosive phase, and epiclastic rocks. The effusive/subvolcanic phase comprises massive porphyritic rhyolite with different degrees of crystallinity, porphyritic rhyolite with flow structure, and microcrystalline rhyolite. The explosive phase is characterized by welded lapilli tuff, lapilli tuff with flow structure, stratified lapilli tuff, and tuff with accretionary lapilli. Sandstones and siltstones characterize epiclastic rocks. There are porphyritic rhyolite dikes that cut the volcanic sequence. The rocks of the Colíder Group are rhyolites (>70 % SiO2) with calcic-alkaline to alkaline-calcic affinity. A rhyolitic rock is predominantly ferroan and metaluminous, while a pyroclastic rock is predominantly magnesian to ferroan and meta- to peraluminous in composition. The rocks have a high LREE content, and slight fractionation of HREE suggests they have hybrid geochemical characteristics of high potassium calc-alkaline, shoshonitic, and suggestive affinities of A-type magmas, probably produced in a post-collisional orogenic environment. These rocks have a relatively high level of Ba and Rb and a negative anomaly for Sr, P, Nb, Ta, and Ti, suggesting an intra-plate mantle source with contributions from a metasomatized mantle edge. The rocks do not have adakitic characteristics nor fertility for Cu-Au (Sr/Y < 1.9 and LaN/YbN < 38.0) as in other regions of the AFMP. The welded lapilli tuff rocks show U-Pb age of 1838 ± 17 Ma and 1817 ± 2 Ma and are the older explosive phases. The effusive/subvolcanic phase has U-Pb ages of 1800 ± 3 Ma and 1792 ± 3 Ma obtained in the massive porphyritic rhyolite. The age interval of approximately 46 Ma (1838–1792 Ma) suggests the presence of two or more volcanic cycles or distinct volcanic events. Based on the interpretation of volcanic and epiclastic deposits and remote sensing products, the paleoenvironmental reconstruction includes subaerial with effusive/subvolcanic and explosive stages in a probable eroded volcanic caldera system with epiclastic rocks from a fluvial depositional system. This volcanic scenario provides more information about the Colíder–Teles Pires volcano-plutonic event, uniquely mapped in AFMP, and offers new insights into the tectonic frame of the Amazonian craton.

Non‐Thermal Escape of Sulfur and Oxygen on Io Driven by Photochemistry

AbstractIo, the closest of Jupiter's four Galileo moons, experiences intense volcanic activity that is induced by Jupiter's powerful tidal forces. The active volcanisms consequently create a tenuous SO2‐dominated atmosphere on Io, from which energetic particles can be easily lost due to the weak gravity field. The photolysis of SO2 triggers a complicated network of chemical reactions, which may be a significant source of atmospheric escape on Io. This study, for the first time, is devoted to evaluating the role of the chemically induced escape of S‐ and O‐containing species on Io by combining previous photochemical results and Monte Carlo model calculations. Different atmospheric conditions are compared, including high‐density volcanic and low‐density quiet scenarios, in which various chemical channels are considered. Our calculations suggest that the escape rates driven by photochemistry on Io are (1.1 − 2.0) × 1027 s−1 for total O and (1.5 − 6.7) × 1026 s−1 for total S, occurring mainly in the atomic form. The escape rates are found to vary extensively with the atmospheric conditions, especially in terms of the intensity of volcanic eruption. In general, photochemical escape is more important than Jeans escape for both atomic O and S for the quiet atmosphere scenario, whereas for the volcanic scenario, it is likely important for atomic S only.

Damage amplification during repetitive seismic waves in mechanically loaded rocks

Cycles of stress build-up and release are inherent to tectonically active planets. Such stress oscillations impart strain and damage, prompting mechanically loaded rocks and materials to fail. Here, we investigate, under uniaxial conditions, damage accumulation and weakening caused by time-dependent creep (at 60, 65, and 70% of the rocks’ expected failure stress) and repeating stress oscillations (of ± 2.5, 5.0 or 7.5% of the creep load), simulating earthquakes at a shaking frequency of ~ 1.3 Hz in volcanic rocks. The results show that stress oscillations impart more damage than constant loads, occasionally prompting sample failure. The magnitudes of the creep stresses and stress oscillations correlate with the mechanical responses of our porphyritic andesites, implicating progressive microcracking as the cause of permanent inelastic strain. Microstructural investigation reveals longer fractures and higher fracture density in the post-experimental rock. We deconvolve the inelastic strain signal caused by creep deformation to quantify the amount of damage imparted by each individual oscillation event, showing that the magnitude of strain is generally largest with the first few oscillations; in instances where pre-existing damage and/or the oscillations’ amplitude favour the coalescence of micro-cracks towards system scale failure, the strain signal recorded shows a sharp increase as the number of oscillations increases, regardless of the creep condition. We conclude that repetitive stress oscillations during earthquakes can amplify the amount of damage in otherwise mechanically loaded materials, thus accentuating their weakening, a process that may affect natural or engineered structures. We specifically discuss volcanic scenarios without wholesale failure, where stress oscillations may generate damage, which could, for example, alter pore fluid pathways, modify stress distribution and affect future vulnerability to rupture and associated hazards.

On the feasibility and usefulness of high-performance computing in probabilistic volcanic hazard assessment: An application to tephra hazard from Campi Flegrei

For active volcanoes, knowledge about probabilities of eruption and impacted areas becomes valuable information for decision-makers to develop short- and long-term emergency plans, for which probabilistic volcanic hazard assessment (PVHA) is needed. High-resolution or spatially extended PVHA requires extreme-scale high-performance computing systems. Within the framework of ChEESE (Center of Excellence for Exascale in Solid Earth; www.cheese-coe.eu), an effort was made to generate exascale-suitable codes and workflows to collect and process in some hours the large amount of data that a quality PVHA requires. To this end, we created an optimized HPC-based workflow coined PVHA_HPC-WF to develop PVHA for a volcano. This tool uses the Bayesian event tree methodology to calculate eruption probabilities, vent-opening location(s), and eruptive source parameters (ESPs) based on volcano history, monitoring system data, and meteorological conditions. Then, the tool interacts with the chosen hazard model, performing a simulation for each ESP set or volcanic scenario (VS). Finally, the resulting information is processed by proof-of-concept-subjected high-performance data analytics (HPDA) scripts, producing the hazard maps which describe the probability over time of exceeding critical thresholds at each location in the investigated geographical domain. Although PVHA_HPC-WF can be adapted to other hazards, we focus here on tephra (i.e., lapilli and ash) transport and deposition. As an application, we performed PVHA for Campi Flegrei (CF), Italy, an active volcano located in one of the most densely inhabited areas in Europe and under busy air traffic routes. CF is currently in unrest, classified as being in an attention level by the Italian Civil Protection. We consider an approximate 2,000 × 2,000 × 40 km computational domain with 2 km grid resolution in the horizontal and 40 vertical levels, centered in CF. To explore the natural variability and uncertainty of the eruptive conditions, we consider a large number of VSs allowing us to include those of low probability but high impact, and simulations of tephra dispersal are performed for each of them using the FALL3D model. Results show the potential of HPC to timely execute a vast range of simulations of complex numerical models in large high-resolution computational domains and analyze great volumes of data to obtain quality hazard maps.

A modular framework for the development of multi-hazard, multi-phase volcanic eruption scenario suites

Understanding future volcanic eruptions and their potential impact is a critical component of disaster risk reduction, and necessitates the production of salient, robust hazard information for decision-makers and end-users. Volcanic eruptions are inherently multi-phase, multi-hazard events, and the uncertainty and complexity surrounding potential future hazard behaviour is exceedingly hard to communicate to decision-makers. Volcanic eruption scenarios are recognised to be an effective knowledge-sharing mechanism between scientists and practitioners, and recent hybrid scenario suites partially address the limitations surrounding the traditional deterministic scenario approach. Despite advances in scenario suite development, there is still a gap in the international knowledge base concerning the synthesis of multi-phase, multi-hazard volcano science and end-user needs. In this study we present a new modular framework for the development of complex, long-duration, multi-phase, multi-hazard volcanic eruption scenario suites. The framework was developed in collaboration with volcanic risk management agencies and researchers in Aotearoa-New Zealand, and is applied to Taranaki Mounga volcano, an area of high volcanic risk. This collaborative process aimed to meet end-user requirements, as well as the need for scientific rigour. This new scenario framework development process could be applied at other volcanic settings to produce robust, credible and relevant scenario suites that are demonstrative of the complex, varying-duration and multi-hazard nature of volcanic eruptions. In addressing this gap, the value of volcanic scenario development is enhanced by advancing multi-hazard assessment capabilities and cross-sector collaboration between scientists and practitioners for disaster risk reduction planning.

The historical case of Paricutin volcano (Michoacán, México): challenges of simulating lava flows on a gentle slope during a long-lasting eruption

Simulating lava flows on a gentle slope is complex since they can propagate in a wide range of directions. It is an even greater challenge to define lava flow trajectories when an eruption lasts over several years and flows cool down, changing the surrounding topography. In this study, we test Q-LavHA, an open source plug-in that simulates lava flow inundation calculating its probability, and using Paricutin’s eruption (1943–1952) in central Mexico as a case study. We have appropriately calibrated the Q-LavHA plug-in for the Paricutin case study, which provides insights on how to better model lava flows in gentle terrain. From this work, we observe that each phase is characterized by a unique set of parameters requiring a careful calibration and that low-relief topographies require special consideration. Our findings could be useful for real-time hazard evaluation in future volcanic scenarios in the Michoacán–Guanajuato volcanic field and elsewhere, where new monogenetic eruptions similar to Paricutin can be expected.

Modeling of a gas slug rising in a cylindrical duct and possible applications to volcanic scenarios

The paper deals with the mathematical modelling of a gas slug rising in a cylindrical duct filled with an incompressible liquid. This research is motivated by a phenomenon commonly observed during Strombolian eruptions at basaltic volcanoes, that is, mildly explosive events driven by a large bubble of magmatic gas (a slug) rising up the conduit and bursting at the surface. The model is compared with the laboratory experiments described in [15] and we prove that the constancy of the slug ascent velocity observed in these experiments is fully justifiable. The model is developed both in the case of a Newtonian fluid and in the case of a non-Newtonian power law fluid, more suitable for magmas, and applied to a volcanic scenario.

Advanced signal recognition methods applied to seismo-volcanic events from Planchon Peteroa Volcanic Complex: Deep Neural Network classifier

Advanced techniques in the recognition and classification of seismo-volcanic events are transcendental when studying active volcanoes, not only for their importance as an accurate real time seismic monitoring procedure but also for the use of their results in modeling the dynamics of the volcanic environment. It is well known that real time seismic monitoring deals with such a large amount of data that it would become an overwhelming job for an operator to do manually. Therefore the use of automatic detection and classification techniques based on the Machine Learning approach are suitable in meeting such a challenge.The aim of this work is to test the capability of the Deep Neural Network (DNN) by using different event parametrization as a confident classifier tool that could permit a reliable seismic catalog to be built in a new and un-analyzed volcanic scenario. We tested different configurations in order to build an approach that was as simple as possible to use this classifier with a limited number of events. In this regard, the feature space was explored in order to select the most significant parameters of the seismic signals. The data used for this analysis corresponds to the Planchon Peteroa Volcanic Complex (PPVC) located in the Transitional Southern Volcanic Zone (TSVZ) between Chile and Argentina, South America. The most significant result of this work was not only that it provided an analysis in terms of performance of this algorithm, especially when the training, validation and test dataset is reliable although definitely reduced, but it also gave an insight of into how an optimal event parametrization can significantly improve the automatic detection and classification of seismo-volcanic events.

Evaluation and Improvement of the Near-Real-Time Linear Fit SO2Retrievals From Suomi NPP Ozone Mapping and Profiler Suite

Changing a logic switch threshold in the linear fit sulfur dioxide (LFSO2) algorithm improves the performance based on the evaluation of the NOAA operational atmospheric SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> near-real-time (NRT) retrieval. The LFSO2 is used to create estimates from measurements made by the Suomi NPP (S-NPP) Ozone Mapping and Profiler Suite (OMPS). We evaluate the LFSO2 and compare the results to those from a principal component analysis (PCA) offline algorithm. Twenty independent volcanic scenarios and one environmental disaster scenario spread over eight years are selected for this comparison. More than three months of Kilauea volcanic activity in 2018 are monitored and are included in this evaluation and comparison. We found that the operational LFSO2 retrievals at lower troposphere (TRL), mid-troposphere (TRM), and lower stratosphere (STL) exhibited a discontinuity and have a saturation-like relationship if compared with PCA results. Using the new retrieval logic, the discontinuity in LFSO2 retrievals and the saturation appearance in comparisons vanished and a close to a linear relationship with the matchup data from the PCA retrieval products is demonstrated. The minimum detectable values for all three SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> layer products and the planetary boundary layer (PBL) products are estimated with the updated LFSO2 algorithm. Results for a volcanic cloud over Colombia for the updated LFSO2 for OMPS and a Differential Optical Absorption Spectroscopy (DOAS) algorithm for the Tropospheric Monitoring Instrument (TROPOMI) measurements are also examined. Similar SO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> total mass estimates over the region are obtained from the two products.

A volcanic scenario for the Frasnian–Famennian major biotic crisis and other Late Devonian global changes: More answers than questions?

Abstract Although the prime causation of the Late Devonian Frasnian–Famennian (F–F) mass extinction remains conjectural, such destructive factors as the spread of anoxia and rapid upheavals in the runaway greenhouse climate are generally accepted in the Earth-bound multicausal scenario. In terms of prime triggers of these global changes, volcanism paroxysm coupled with the Eovariscan tectonism has been suspected for many years. However, the recent discovery of multiple anomalous mercury enrichments at the worldwide scale provides a reliable factual basis for proposing a volcanic–tectonic scenario for the stepwise F–F ecological catastrophe, specifically the Kellwasser (KW) Crisis. A focus is usually on the cataclysmic emplacement of the Viluy large igneous province (LIP) in eastern Siberia. However, the long-lasted effusive outpouring was likely episodically paired with amplified arc magmatism and hydrothermal activity, and the rapid climate oscillations and glacioustatic responses could in fact have been promoted by diverse feedbacks driven by volcanism and tectonics. The anti-greenhouse effect of expanding intertidal–estuarine and riparian woodlands during transient CO2-greenhouse spikes was another key feedback on Late Devonian land. An updated volcanic press-pulse model is proposed with reference to the recent timing of LIPs and arc magmatism and the revised date of 371.9 Ma for the F–F boundary. The global changes were initiated by the pre-KW effusive activity of LIPs, which caused extreme stress in the global carbonate ecosystem. Nevertheless, at least two decisive pulses of sill-type intrusions and/or kimberlite/carbonatite eruptions, in addition to flood basalt extrusions on the East European Platform, are thought to have eventually led to the end-Frasnian ecological catastrophe. These stimuli have been enhanced by effective orbital modulation. An attractive option is to apply the scenario to other Late Devonian global events, as evidences in particular by the Hg spikes that coincide with the end-Famennian Hangenberg Crisis.

An impact with a dash of volcanism

Mass Extinction Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. The best model fits to the data required most outgassing to occur before the impact. When combined with other lines of evidence, these models support an impact-driven extinction. However, volcanic gases may have played a role in shaping the rise of different species after the extinction event. Science , this issue p. [266][1] [1]: /lookup/doi/10.1126/science.aay5055

Increasing Resilience through Interaction: Stakeholder Workshop on Aviation and Volcanic Ash

The Eyjafjallajokull volcanic eruption in 2010 illustrated the threat that Icelandic volcanoes can pose to global air transportation and connected economy. It highlighted the necessity for crisis management and contingency planning that crosses borders. This research obtained insights into how the European aviation volcanic risk management has progressed since 2010. It developed escalating volcanic scenarios to investigate the robustness of the aviation sector and to identify improved mitigation measures. This paper presents a multi-level methodology to build a lasting relationship with, and between, stakeholders and to obtain relevant data. The first step consisted of establishing a face-to-face interaction with stakeholder representatives on an individual basis. Subsequently the group was invited to a one-day participatory stakeholder workshop where extreme volcanic events and their effects on aviation were investigated using scenario narratives. The workshop’s set-up proved successful in enabling discussions and obtaining information. The stakeholders’ positive response to the invitation, as well as their feedback after the workshop, illustrate their interest in this type of workshop. The feedback showed that the stakeholders appreciated the opportunity to meet and specifically to discuss aviation contingency issues. The workshop raised awareness and facilitated information flow between the stakeholders. The paper describes this case and provides generalized guidance on how to build a fruitful interaction between interviewees in a study, sheds light on the resulting impact on the results, and presents opportunities to create value beyond the study.

Hypothesis of Lithocoding: Origin of the Genetic Code as a "Double Jigsaw Puzzle" of Nucleobase-Containing Molecules and Amino Acids Assembled by Sequential Filling of Apatite Mineral Cellules.

The hypothesis of direct coding, assuming the direct contact of pairs of coding molecules with amino acid side chains in hollow unit cells (cellules) of a regular crystal-structure mineral is proposed. The coding nucleobase-containing molecules in each cellule (named "lithocodon") partially shield each other; the remaining free space determines the stereochemical character of the filling side chain. Apatite-group minerals are considered as the most preferable for this type of coding (named "lithocoding"). A scheme of the cellule with certain stereometric parameters, providing for the isomeric selection of contacting molecules is proposed. We modelled the filling of cellules with molecules involved in direct coding, with the possibility of coding by their single combination for a group of stereochemically similar amino acids. The regular ordered arrangement of cellules enables the polymerization of amino acids and nucleobase-containing molecules in the same direction (named "lithotranslation") preventing the shift of coding. A table of the presumed "LithoCode" (possible and optimal lithocodon assignments for abiogenically synthesized α-amino acids involved in lithocoding and lithotranslation) is proposed. The magmatic nature of the mineral, abiogenic synthesis of organic molecules and polymerization events are considered within the framework of the proposed "volcanic scenario".

On Discriminating between GCM Forcing Configurations Using Bayesian Reconstructions of Late-Holocene Temperatures*

AbstractSeveral climate modeling groups have recently generated ensembles of last-millennium climate simulations under different forcing scenarios. These experiments represent an ideal opportunity to establish the baseline feasibility of using proxy-based reconstructions of late-Holocene climate as out-of-calibration tests of the fidelity of the general circulation models used to project future climate. This paper develops a formal statistical model for assessing the agreement between members of an ensemble of climate simulations and the ensemble of possible climate histories produced from a hierarchical Bayesian climate reconstruction. As the internal variabilities of the simulated and reconstructed climate are decoupled from one another, the comparison is between the two latent, or unobserved, forced responses. Comparisons of the spatial average of a 600-yr high northern latitude temperature reconstruction to suites of last-millennium climate simulations from the GISS-E2 and CSIRO models, respectively, suggest that the proxy-based reconstructions are able to discriminate only between the crudest features of the simulations within each ensemble. Although one of the three volcanic forcing scenarios used in the GISS-E2 ensemble results in superior agreement with the reconstruction, no meaningful distinctions can be made between simulations performed with different estimates of solar forcing or land cover changes. In the case of the CSIRO model, sequentially adding orbital, greenhouse gas, solar, and volcanic forcings to the simulations generally improves overall consensus with the reconstruction, though the distinctions are not individually significant.

Long-term volcanic hazard assessment on El Hierro (Canary Islands)

Abstract. Long-term hazard assessment, one of the bastions of risk-mitigation programs, is required for land-use planning and for developing emergency plans. To ensure quality and representative results, long-term volcanic hazard assessment requires several sequential steps to be completed, which include the compilation of geological and volcanological information, the characterisation of past eruptions, spatial and temporal probabilistic studies, and the simulation of different eruptive scenarios. Despite being a densely populated active volcanic region that receives millions of visitors per year, no systematic hazard assessment has ever been conducted on the Canary Islands. In this paper we focus our attention on El Hierro, the youngest of the Canary Islands and the most recently affected by an eruption. We analyse the past eruptive activity to determine the spatial and temporal probability, and likely style of a future eruption on the island, i.e. the where, when and how. By studying the past eruptive behaviour of the island and assuming that future eruptive patterns will be similar, we aim to identify the most likely volcanic scenarios and corresponding hazards, which include lava flows, pyroclastic fallout and pyroclastic density currents (PDCs). Finally, we estimate their probability of occurrence. The end result, through the combination of the most probable scenarios (lava flows, pyroclastic density currents and ashfall), is the first qualitative integrated volcanic hazard map of the island.

Elastic models of magma reservoir mechanics: a key tool for investigating planetary volcanism

Abstract Understanding how shallow reservoirs store and redirect magma is critical for deciphering the relationship between surface and subsurface volcanic activity on the terrestrial planets. Complementing field, laboratory and remote sensing analyses, elastic models provide key insights into the mechanics of magma reservoir inflation and rupture, and hence into commonly observed volcanic phenomena including edifice growth, circumferential intrusion, radial dyke swarm emplacement and caldera formation. Based on finite element model results, the interplay between volcanic elements – such as magma reservoir geometry, host rock environment (with an emphasis on understanding how host rock pore pressure assumptions affect model predictions), mechanical layering, and edifice loading with and without flexure – dictates the overpressure required for rupture, the location and orientation of initial fracturing and intrusion, and the associated surface uplift. Model results are either insensitive to, or can readily incorporate, material and parameter variations characterizing different planetary environments, and they also compare favourably with predictions derived from rheologically complex, time-dependent formulations for a surprisingly diverse array of volcanic scenarios. These characteristics indicate that elastic models are a powerful and useful tool for exploring many fundamental questions in planetary volcanology.

HASSET: a probability event tree tool to evaluate future volcanic scenarios using Bayesian inference

Event tree structures constitute one of the most useful and necessary tools in modern volcanology for assessment of hazards from future volcanic scenarios (those that culminate in an eruptive event as well as those that do not). They are particularly relevant for evaluation of long- and short-term probabilities of occurrence of possible volcanic scenarios and their potential impacts on urbanized areas. In this paper, we introduce Hazard Assessment Event Tree (HASSET), a probability tool, built on an event tree structure that uses Bayesian inference to estimate the probability of occurrence of a future volcanic scenario and to evaluate the most relevant sources of uncertainty from the corresponding volcanic system. HASSET includes hazard assessment of noneruptive and nonmagmatic volcanic scenarios, that is, episodes of unrest that do not evolve into volcanic eruption but have an associated volcanic hazard (e.g., sector collapse and phreatic explosion), as well as unrest episodes triggered by external triggers rather than the magmatic system alone. Additionally, HASSET introduces the Delta method to assess precision of the probability estimates, by reporting a 1 standard deviation variability interval around the expected value for each scenario. HASSET is presented as a free software package in the form of a plug-in for the open source geographic information system Quantum Gis (QGIS), providing a graphically supported computation of the event tree structure in an interactive and user-friendly way. We also include further in-depth explanations for each node together with an application of HASSET to Teide-Pico Viejo volcanic complex (Spain).