Advancements in volcanology since the early 2000’s have seen a steady increase in our understanding of the way tephra is generated, transported and deposited, and has facilitated a much more comprehensive understanding of (1) how frequently explosive eruptions occur on a global scale, (2) how different volcanic systems behave, and (3) the timescales upon which different hazards may emerge across different regions. Coupled with advances in numerical/computational tephra dispersion modelling, we are becoming increasingly informed of past eruptions and their processes, as well as the tracking and forecasting of current and real-time explosive eruptions.
We invite contributions that continue to improve our understanding of explosive eruption dynamics through the study of tephra emission, dispersal, and preservation; encouraging submissions from a variety of research themes including (but not limited to) physical volcanology, tephrochronology, geochemistry/petrology, stratigraphy, computer modelling, environmental management, and hazard forecasting. This session runs in parallel with an open call for paper submissions to a Geological Society of London and AGU GeoHorizons book volume titled “Tephra: from reconstructing past volcanic eruptions to modelling and forecasting future hazards” edited by Hodgetts et al. Thus, we particularly encourage submissions that demonstrate interdisciplinary science to further expand our knowledge of tephra-generating eruptions and their processes.
This session is sponsored by the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) Commission on Tephra Hazard Modelling (THM) and Commission on Tephrochronology (COT).
Orals: Tue, 5 May, 16:15–18:00 | Room -2.21
Submarine volcanic eruptions can form subaerial plumes that frequently reach the troposphere or even the stratosphere. Despite this, the impact of submarine eruptions on ash transport and related hazards remains unclear due to a lack of clear geological record. Here, we review the impact of submarine volcanoes on ash generation and transport in the Earth system by combining thermal, textural and chemical analysis of volcanic ash from the 15 January 2022 eruption of Hunga volcano (Tonga). We used flash differential scanning calorimetry to perform enthalpy relaxation geospeedometry, which allowed us to determine the natural cooling rates of individual ash grains formed during magma-seawater interaction. Synchrotron-based nano-tomography and subsequent 3D image analysis were used to link initial magma texture, thermal crack propagation and resulting ash characteristics (density and morphology). Chemical analysis included quantification of leachate concentration and isotopic d34S and d37Cl signatures of the Hunga ash. Thermal and 3D textural analysis revealed that high cooling rates (hundreds of K.s-1) during magma-seawater interaction led to high levels of thermal stress, fracturing and pervasive fine ash generation. Ash morphology, density and porosity following thermal granulation were strongly influenced by the starting vesicle size distribution. Heat transfer and magma cooling were accompanied by intense evaporation of seawater and subsequent sea-salt (dominantly halite and Ca-sulphate) formation, with a limited role of gas scavenging on salt precipitation and volatile budget during this eruption. Sea salt formation promoted fine ash aggregation, thereby reducing the residence time of volcanic ash within the troposphere and stratosphere. Together, these processes may explain the ash-poor and sulphate-poor nature of volcanic clouds formed during submarine eruptions and the lack of clear geological record, despite evidence for repeated intrusions of submarine plumes in the stratosphere in historical times.
How to cite: Colombier, M., Bonifacie, M., Bissbort, T., Burke, A., Cronin, S. J., Delmelle, P., Dingwell, D. B., Hess, K.-U., Huebsch, M., Kula, T., Latu’ila, F., Lavallée, Y., Paredes‑Mariño, J., and Scheu, B.: Ash generation and transport during explosive submarine eruptions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-13749, 2026.
Volcanic hazard assessments are in part constrained by understanding the past behaviour of a volcano (e.g., eruptive frequency and magnitude), this is largely reconstructed using tephra deposits preserved proximal to source. However, these near-vent eruption records are often fragmentary and incomplete owing to burial and erosion processes, thus hampering the accuracy of hazard assessments. Here, we capitalise on the potential of long, undisturbed records of ash fall events preserved in East Asian marine and lacustrine sedimentary archives, typically positioned >100 km from volcanic sources, to plug the gaps in near-source eruption records. The extraction and identification of microscopic ash layers (cryptotephra) from sedimentary archives is adopted to provide important constraints on the timing of mid-intensity explosive eruptions, which are frequently under-reported at source.
Following detailed cryptotephra investigations, we present a new eruption record captured by high-resolution sediment cores collected from the Sea of Japan spanning approximately the last 200,000 years. Detailed geochemical fingerprinting is used to assign tephra and cryptotephra deposits to volcanic source, and where possible to known eruption units, some of which are the target of zircon double-dating (ZDD). Furthermore, the chemical signatures are used to link the Sea of Japan tephra layers to those preserved in the precisely dated sediments of Lake Suigetsu (Honshu Island), providing important chronological constraints on our newly developed eruption record. Our investigations provide evidence of near-vent under-reporting of explosive eruptions and new insights into the repose periods between pre-historic eruptions at specific volcanoes.
How to cite: Albert, P. G., Jones, G., Buckland, H. M., Smith, V. C., McLean, D., Watts, E. J., Ikehara, K., Staff, R., Suzuki, T., Danisik, M., Schmitt, A. K., Manning, C., Vineberg, S., Cullen, V., Nakagawa, T., and Sagawa, T.: Constraints on the timing of East Asian explosive volcanism: insights from cryptotephra deposits preserved in marine and lacustrine archives, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18780, 2026.
Fragmentation during explosive silicic volcanic eruptions produces angular, porous pyroclasts that are subsequently transported within eruption plumes or pyroclastic density currents (PDCs). Within PDCs, particle–particle and particle-substrate interactions substantially modify their size and shape through abrasion and secondary fragmentation, causing, in particular, significant pumice rounding associated with ash generation. The efficiency of these processes is directly linked to the textural properties of the pumice clasts (i.e., pore and crystal characteristics), but this aspect remains poorly constrained to date.
We performed controlled tumbling experiments using pumice clasts from the 13 ka Laacher See (LS, Eifel, Germany) and the 79 AD Vesuvius (VS, Italy) eruptions. Both sample sets are phonolitic in composition but texturally distinct. At different times during tumbling (5, 10, 15, 20, and 60 minutes), the bulk samples were sieved at 2 mm to quantify ash generation. Shape parameters (axial ratio, convexity, form factor, and solidity), and petrophysical properties (volume and porosity) were quantified on a constant subset of 100 clasts (colour impregnated) to constrain the evolution of individual particles. In addition, we analysed the texture (porosity, pore connectivity, crystal content, and pore size distribution) of the starting material and tumbled clasts.
In all experiments, clasts exhibit a continuous but decelerating rate of change in shape and surface roughness, approaching a time-invariant state. This kinetic behaviour, characterized by a fast initial change followed by a progressively slower evolution, is analogous to structural relaxation processes in glasses. Thus, the shape evolution and surface roughness were framed within a structural relaxation framework in terms of relaxation times. The results reveal systematic differences in abrasion behaviour between the two sample sets. LS pumice displays faster shape evolution and higher ash production than VS pumice, consistent with its higher porosity and pore connectivity as well as lower crystal content.
Our findings confirm the major control of pumice texture on abrasion propensity during transport. The continuous ash generation will ‘buffer’ the decrease of ash concentration during PDC transport by sedimentation and elutriation and thus contribute to maintaining PDC mobility high and CO-PDC plume formation. Framing these processes in terms of relaxation times provides a quantitative link between clast texture, shape evolution, ash generation, and the mobility of PDCs.
How to cite: Figueiredo, C., Colombier, M., Kueppers, U., Angleitner, M., Schuh, S., Pereira, L., Lancelotti, R., Sulpizio, R., Buono, G., and Pappalardo, L.: Textural dependence of shape evolution during granular flow, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7585, 2026.
Explosive volcanic eruptions can generate widespread hazards, particularly ash plumes, capable of disrupting societies far beyond the source volcano. Ash dispersal can be strongly controlled by seasonal atmospheric circulation. Distal volcanic ash (tephra) layers preserved within annually-layered sediments (varves) can provide chronological control and seasonal insights into past eruptions and atmospheric regimes responsible for ash dispersal, allowing for the assessment of past climatic regimes at seasonal resolution and future hazard insight.
Southwest Asia hosts several active volcanic centers. Yet, widespread ash plume impacts in this region remain largely overlooked in hazard assessments. The annually-laminated lacustrine record of the ICDP Dead Sea core (5017-1A) provides a unique opportunity to reconstruct such hazard scenarios in the past at seasonal resolution. Here, we present the identification of the S1 tephra from Mt. Erciyes (Central Anatolian Volcanic Province, Turkey) dated to ~8.9 kya, as a microtephra layer preserved within a winter flood layer of the Dead Sea record. This unique finding provides the first direct evidence for the seasonal timing of the S1 eruption. Major and trace element geochemical analysis allows for robust correlations between the Dead Sea and other distal tephra sites in the region. By integrating this regional tephra network with Ash3D model for ash plume dispersal, we reconstructed the past winter atmospheric circulation pattern that allowed the transport of the ash southwards from Central Anatolia. The model results show that only specific winter circulations and plume heights reproduce the observed tephra distribution, tightly constraining both eruption dynamics and seasonal atmospheric behavior. These results allow for modern hazard analogues and potential widespread impacts to be inferred if Mt. Erciyes were to erupt under the same atmospheric conditions today. Overall, this study demonstrates that combining seasonally resolved tephra records with ash dispersal modelling provides new constraints on past eruption impacts and atmospheric circulation, offering a framework for assessing future explosive eruption hazards in an underrepresented, yet highly vulnerable region.
How to cite: Kearney, R. J., Blanchet, C., Pflug, K., Neugebauer, I., Schwab, M. S., Emmanuel, G., von Schijndel, V., Appelt, O., Tjallingii, R., and Brauer, A.: Winter winds and volcanic ash: Seasonal controls and modern hazards using past distal S1 tephra dispersal from Mt. Erciyes, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14387, 2026.
Lava domes typically form during the eruption of highly viscous lava from a volcanic vent. Due to their high viscosity, they spread slowly over a limited spatial area, unlike less viscous lava flows. However, lava domes are potentially lethal because they cyclically collapse, generating pyroclastic flows, or explode. To date, these latter events are only partially understood and are linked to various sources of overpressure in a context, often overlooked, of variable effusion rates. Here, we present 3D numerical simulations of the growth of a viscous lava dome, allowing us to determine the total and dynamic pressure, as well as the components of the strain rate and stresses within the dome, and to study the influence of the flow rate on pressure, strain rate, and stresses. Using a non-dimensional scale analysis involving the dimensions of the vent, we show the different growth phases of a lava dome during a sequence involving (i) a phase of constant input flow rate through the vent; followed by (ii) the cessation of discharge (i.e. zero input flow rate through the vent). Considering the radial, hoop and vertical shear strain rate components, respectively, err, eθθ and erz , as well as the corresponding stresses and comparing the magnitudes of the latter to typical yield strengths, we examine through space and time where ring fractures, radial tensile fractures, and shear fractures may occur. We show that the location of these different fracture mechanisms depend on the growth phase and the time at which the eruption ceases (i.e. the time when the imposed flow rate is set to zero). Lastly, the arrest of lava discharge is found to lead to rapid dome depressurization and subsidence. We will discuss the implications of sudden lava dome depressurization as triggers for the breakdown and explosion of lava domes.
How to cite: Mériaux, C. A., May, D. A., and Jaupart, C.: Lava domes: growth phases and deformation under variable effusion rate, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7176, 2026.
Pyroclastic density currents (PDCs) have the potential to generate co-PDC plumes, which segregate and buoyantly rise from the underlying gravity current. Co-PDCs are composed of hot gas and fine particles (e.g., < 90 μm) and typically have high-aspect ratio source geometries. Using the atmospheric-dispersion model, NAME, we perform a series of model runs that vary the particle release height and associated mass eruption rate for the eight different weather patterns that characterise the UK and the surrounding European area. We examine the ash cloud concentration as a function of vertical elevation (or flight level) within the atmosphere. We find that the ash clouds generated by PDCs have relatively small areas but are compact in shape and contain high ash concentrations, especially in early hours after particle release. The elevation of maximum mass resides in the vertical release region (within the first 36 h), and the maximum flight level achieved by the ash is 50 to 150 flight levels above the release region. Our results are discussed in terms of operational modelling by volcanic ash advisory centres for the aviation sector and the newly introduced concentration thresholds for quantitative volcanic ash forecasts (QVA). When applying these thresholds, most clouds are very high-concentrated, often above 10 mg m-3 within the first hours of particle release and thus represent a hazard to aviation.
How to cite: Hagenbourger, M., Jones, T., Beckett, F., and Engwell, S.: Modelling the ash concentration, transport, and dispersal of co-PDC ash clouds: implications for the aviation hazard, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-881, https://doi.org/10.5194/egusphere-egu26-881, 2026.
Tenerife (Canary Islands) has experienced numerous explosive felsic eruptions over the last 300 kyrs. The stratigraphy and timing of these events within the most recent cycle of phonolitic volcanism, the Diego Hernandez Formation (ca. 600 – 170 ka), is constrained proximally, with petrological studies (whole-rock and isotopes) revealing the generation and storage of melts below the caldera complex. It is likely that several of these events dispersed distally across the North West African margin. However, despite the number of large-magnitude eruptions over the last 300 kyrs, there are limited glass chemical data for these eruption deposits. The lack of glass chemical datasets means distal fallout from these events cannot be robustly correlated to a particular eruption, limiting their use as chronological markers in terrestrial or marine records.
Here we present the major and trace element compositions of volcanic glass shards from major eruption units in the last 300 kyrs, including the deposits of large (VEI ≥ 6) caldera-forming eruptions, such as El Abrigo at ca. 170 ka. The major element compositions are heterogenous, which is consistent with eruptions tapping multiple melt bodies at various stages of magmatic evolution, and there is little variation between successive eruptions. Nonetheless, the trace elements are relatively unique and thus provide distinctive chemical fingerprints for each eruption. These trace element compositions have facilitated the correlation of some of these eruptions to offshore marine records, providing further occurrences that can be used to refine dispersal and magnitude estimates. Furthermore, since at least some of these eruption deposits are well dated, the associated tephra layers can be used as chronological markers in sedimentary sequences in which the tephra are preserved.
How to cite: Wilkinson-Rowe, E., McLean, D., Horn, E., Brown, R., project members, C. A., Barton, N., and Smith, V.: Chemical fingerprints of large felsic eruptions in the last 300 kyrs from Tenerife, Canary Islands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11547, 2026.
Geochemically characterised tephra layers are widely used for synchronising and dating paleoenvironmental records. Advances in the detection of invisible tephra horizons have led to the ongoing development and integration of regional tephra frameworks. Although there are multiple volcanic sources that could potentially have supplied volcanic ash to the South Pacific region, paleoclimatic archives in this area currently lack tephra markers.
Here, we report the first discovery of a cryptotephra layer in the Cook Islands. Volcanic glass shards were collected by sieving and applying heavy liquid separation technique from a laminated gyttja sequence in Lake Teroto, Atiu Island. The major elements were obtained by electron microprobe analysis. Based on the geochemical data, the detected layer is attributed to the Okataina Volcanic Centre, located 3,000 km from the coring site. Radiocarbon dating below the layer narrows the potential source eruption to the Whakatāne event, which occurred 5,500 years BP (Smith et al., 2006). It is presumed that the studied tephra originates from the M-type batch of magma from the Makatiti-Tapahoro vents, which were the main source of Plinian tephra falls (Kobayashi et al., 2005).
Our findings indicate the most distal Holocene tephra from the Okataina Volcanic Centre and significantly extend the mapped dispersal of the Whakatāne eruption. The discovery of New Zealand-sourced cryptotephra in the Cook Islands also highlights the potential for further utilisation of volcanic ash in the South Pacific, contributing to the development of a regional Holocene tephrochronological lattice.
How to cite: Garova, E., Bourne, A., and Sear, D.: Initial tephrochronology for Cook Islands sediments — evidence of far travelled New Zealand ash layers, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14242, 2026.
A new chronostratigraphic framework for deep-sea volcaniclastic sedimentation in the Somali Basin provides key constraints on the timing, magnitude, and recurrence of explosive volcanism associated with the Comoros Archipelago over the past ~1.5 Myr. Multibeam bathymetry, high-resolution seismic reflection data, and seven sediment cores recovered north of the archipelago are combined to establish basin-scale correlations of volcaniclastic turbidites. Temporal control is achieved through tuning of oxygen isotope stratigraphies.
Seismic–core correlations reveal multiple regionally extensive event deposits, with individual layers covering minimum areas ranging from ~20 km² to more than 130,000 km². Petrographic observations and geochemical analyses show that the turbidites are dominated by basaltic to trachybasaltic glass fragments (sideromelane and tachylite), consistent with a Comorian volcanic provenance. The large volumes, widespread dispersal, and sharp basal contacts of these deposits support direct syn-eruptive emplacement by eruption-fed sediment gravity flows, rather than post-eruptive remobilization. Such deposits require highly energetic explosive activity, consistent with Surtseyan to (sub-)Plinian eruptions capable of generating large quantities of pyroclastic material and transporting it hundreds of kilometers into the deep basin.
The resulting chronostratigraphy documents recurrent phases of intensified volcaniclastic sedimentation at ~1.63–1.35 Ma, ~1.03–0.72 Ma, and ~0.40–0.13 Ma, indicating episodic but long-lived explosive volcanism in the Comoros region during the Quaternary. These findings highlight the Comoros Archipelago as a major center of explosive basaltic volcanism in the western Indian Ocean and underscore the importance of deep-marine sedimentary records for assessing the frequency, magnitude, and hazard potential of large-scale submarine eruptions.
How to cite: Tzevahirtzian, A., Zaragosi, S., Famin, V., Bachèlery, P., Paquet, F., Bernard, J., Berthod, C., Médard, E., Thinon, I., Marchès, E., Beaufort, L., Vidal, L., Etcheverry-Rambeau, L., Bignon, J., Turel, C., Lecomte, M., Charlier, K., Rossignol, L., and Bolton, C. T.: Explosive volcaniclastic sedimentation in the Comoros Archipelago over the past 1.5 Myr (western Indian Ocean), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17220, 2026.
Posters on site: Tue, 5 May, 08:30–10:15 | Hall X2
Cryptotephra fingerprinting is the most robust method for linking volcanic sulfate deposits in polar ice cores with their eruptive source. Advances in the detection and geochemical characterization of extremely fine cryptotephra deposits (e.g., volcanic glass shards <10 μm in size) have enabled the source identification of increasingly distal eruptions preserved in Greenland and Antarctic cores. These developments improve constraints on eruption timing, sulfur loading, and ash dispersal, allowing reconstruction of detailed volcanic histories assessing the provenance and recurrence rate of events with global, societal consequences.
Here, we investigate evidence for volcanic eruptions occurring during the interval 680-690 CE, preserved in Greenland ice core Tunu2013, and Antarctic ice core B53. This targeted time period includes the 5th largest volcanic stratospheric sulfur injection of the Common Era (last 2000 years), deposited as a contemporaneous sulfur peak in both hemispheres in 682 CE. Previous hypotheses have suggested three closely timed VEI 5-6 eruptions from New Britain Island, Papua New Guinea, as the most likely source candidates for this sulfur deposit.
By combining cryptotephra geochemical fingerprinting with sulfur isotope analysis, we provide new insights into the sources, plume height, sulfur emission and tephra transport of major eruptions occurring between 680-690 CE, including the 682 CE event and the Newberry Pumice 687 CE eruption. These results contribute to ongoing efforts to identify the sources of the largest Common Era sulfur deposits in polar ice cores and build detailed records of volcanic eruptions associated with global climate perturbations and ultra-distal ash dispersal.
How to cite: Innes, H., Hutchison, W., Firth, C., McConnell, J. R., Chellman, N. J., Blong, R., Jenkins, S. F., Sigl, M., Jensen, B. J. L., Neall, V., and Burke, A.: New ice core insights into the sources and sulfur emission of the largest Common Era eruptions: a case study of eruptions from 680-690 CE, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18473, 2026.
In 2021, 25 sediment cores were gathered in the proximal region of Mayotte Island, in the Comoros Archipelago. A total of ~300 meters was retrieved shedding light into the past volcanic activity of the island, but also of the submarine Eastern Mayotte Volcanic Chain (EMVC) discovered in 2019. By investigating the sediment cores, up to 1 cm resolution scale in the uppermost sedimentary sequence of core MAY15-CS02, we underlined the presence of abundant, fresh, cryptotephra witnessing recent explosive activity from ~2 to 6.5 ka, and a major event at 7.5 ka that could either originate from Petite-Terre or the submarine Horseshoe volcano [1]. We also identified new submarine explosive eruptions of phonolitic composition, marked by high-alkali contents, which differs from the most recent activity of Petite-Terre and the Horseshoe [2]. A 1-meter-thick deposit dated at around 300 ka presents a less evolved composition than the aforementioned eruptions, and coarser material up to several centimetres scale composed this deposit, shedding light on another major volcanic event that affected Mayotte. Using high-resolution x-ray tomography 3D scans and geochemical analyses together with textural observations, we investigate its origin (subaerial vs. submarine) and emplacement mechanisms, and fine tune Mayotte volcanic history. We present here the key results of this investigation and emphasize the importance of analysing, at a high resolution, proximal (≤5 km from the island coast) sediment cores as they do contain crucial information retrieved from volcanic-related deposits, tephra and cryptotephra to comprehend the overall activity that shaped an island.
[1] Lebas et al. 2024. IAVCEI-COT abstract, Catania.
[2] Baudry et al. 2025. IAVCEI abstract, Geneva.
How to cite: Lebas, E., Besson, E., Falvard, S., Gurioli, L., Jouet, G., and Paris, R.: Deciphering the origin and emplacement mechanisms of Mayotte submarine and subaerial volcaniclastic deposits using x-ray tomography and geochemical fingerprinting, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23073, 2026.
Pyroclastic density currents are among the most fatal events associated with volcanic hazards. When pyroclastic density currents escape their confining channels and become unconfined, then they inundate the inhabited areas and destroy everything in their path. Pyroclastic density currents (PDCs) are hot mixtures of volcanic rock and gases that can flow long distances at velocities of tens to hundreds of kilometers per hour from the source. PDCs are complex volcanic flows whose dynamics, occurrence, and flow paths are mostly unpredictable. In this project, we are investigating the rheological properties of pyroclastic mixtures sampled from the PDCs’ deposits of the Pollena 472 ACE eruption of Mt. Vesuvius (Italy). First, we characterized the grain size distribution, density, and morphology of the used mixtures, as well as performed BET analysis and Shear cell experiments. Then, using an Anton Paar MCR702e rheometer, we Conduct Shear cell experiments to gain insight into the mobility of the studied granular materials, specifically by measuring their internal friction angle, cohesion (if any), unconfined yield strength, and flowability. In this presentation, I will present preliminary results of all my performed experiments and their implications on the rheology of Pyroclastic Density Currents.
How to cite: Ammar, M.: Rheological Properties of Pyroclastic Flow Mixtures, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2465, https://doi.org/10.5194/egusphere-egu26-2465, 2026.
NEVA2 explores the impacts of large explosive volcanic eruptions during the Holocene, with a focus on the southern end of the Central Volcanic Zone (CVZ) of the Andes. These rare but catastrophic events release enormous volumes of pyroclastic material and gases, reshaping landscapes for centuries and influencing the global climate. Despite their significance, the cumulative and cascading effects of these processes on the Earth’s critical zone—the interface of rock, soil, water, air, and life—as well as their role in past climate variability remain insufficiently constrained.
The project targets a unique natural laboratory in Chile and Argentina, where preliminary evidence suggests previously undocumented Holocene eruptions, including a major event at Nevado Tres Cruces volcano around 1,300 years BP (around the 8th century). This eruption appears to coincide with palaeoclimatic anomalies and cultural changes in pre-Hispanic societies, offering an exceptional opportunity to link geological, environmental, and archaeological records.
NEVA2 aims to identify and date large Holocene eruptions in the southern CVZ, model their dynamics and dispersal using advanced simulation tools, and assess multiscale impacts on the critical zone. It also seeks to correlate eruption timelines with palaeoclimate archives to evaluate associated climatic effects and disseminate findings to scientific communities, stakeholders, and the public.
Combining field surveys, laboratory analyses and modelling approaches, NEVA2 will deliver novel insights into volcanic hazards, provide new Holocene tephrochronological markers for the Southern Hemisphere, and contribute to improved risk mitigation strategies. The project also promotes education and stakeholder engagement to enhance resilience in volcanic regions.
The NEVA2 Project (Ref. ProID2024010012) is funded by the Canary Islands Agency for Research, Innovation and Information Society (ACIISI) and by the European Union under the Canary Islands ERDF Programme 2021–2027. Institutional support was provided by the GEOVOL research group (iUNAT, ULPGC) and Structure and Dynamics of the Earth (Generalitat de Catalunya, 2021 SGR 00413).
How to cite: Fernandez-Turiel, J.-L., Rodriguez-Gonzalez, A., Perez-Torrado, F.-J., Cabrera, M. C., Ratto, N., Polanco, E., Benavente, D., N. García-Martínez, N., and Estevez, E.: The southernmost Central Volcanic Zone of the Andes: a natural laboratory for reconstructing the impact of large explosive Holocene eruptions (NEVA2), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2954, https://doi.org/10.5194/egusphere-egu26-2954, 2026.
The collapse of high-temperature volcanic material is a widespread process affecting lava domes, lava flows and proximal volcaniclastic accumulations, including spatter agglutinates and crater-rim deposits. Such collapses can generate small-volume pyroclastic density currents (PDCs; 10³–10⁷ m³), capable of travelling several kilometres while maintaining temperatures of up to ~700°C. Failure of volcaniclastic material and the generation of deposit-derived PDCs represent a major hazard, particularly during effusive to violent Strombolian activity. These events commonly occur with limited or no clear precursory signals, posing a threat to both local communities and visitors. Two end-member mechanisms are identified: (i) gravitational instability of hot volcaniclastic deposits dominated by rapid proximal accumulation during fire-fountaining and lava flow emplacement on steep slopes (Fuego-type), with basal undercutting acting as a secondary, facilitating process; and (ii) enhanced magmatic thrust exerted by dense, degassed magma ascending within the conduit, which may destabilise crater rims and proximal structures (Arenal-type). Comparable processes operate during gravitational lava dome collapses, driven either by gravitational loading alone (Merapi-type) or by internal overpressure (Peléan-type).
Robust hazard assessment requires constraining both the long-term preconditioning factors that control volcanic slope instability and the short-lived processes capable of triggering collapse. This study integrates field-based stratigraphic and geomechanical observations with numerical modelling of slope instability, supported by a comprehensive database of historical deposit-derived PDC events. Geophysical monitoring data are incorporated within these databases to provide contextual constraints, while the primary focus of the analysis remains on field evidence and physics-based modelling approaches. Slope stability is analysed through two-dimensional limit-equilibrium methods adopting multiple shear-strength criteria, informed by site-specific stratigraphic constraints and mechanical characterisation of proximal deposits.
Sensitivity analyses highlight the key role of slope geometry, deposit thickness, mechanical properties and structural discontinuities in controlling failure conditions. The consistency between modelled unstable sectors and observed collapse areas supports the robustness of the proposed framework and its applicability to other volcanic systems characterised by similar morphologies and depositional environments. The approach can be readily extended to lava dome instability by accounting for dome lithology, mechanical heterogeneity and the properties of surrounding talus, as well as for the influence of endogenous and exogenous growth phases and the presence of hydrothermally altered material near conduits and crater rims.
How to cite: Di Traglia, F., Falasconi, A., and Borselli, L.: From Proximal Accumulation to Collapse: Mechanisms of Deposit-Derived Pyroclastic Density Currents, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3473, https://doi.org/10.5194/egusphere-egu26-3473, 2026.
Particle-laden volcanic flows are hazardous across a wide range of settings, from dispersing ash clouds to pyroclastic density currents (PDCs). Their impacts depend not only on bulk mass loading and particle size, but also on how particles self-organise in space. Yet, many studies and hazard models are built on bulk- or layer-averaged properties, so concentration inhomogeneities within the flow are poorly constrained. A key missing piece is clustering (preferential concentration): particles concentrate into dense regions separated by voids, creating sharp local contrasts that can alter settling, generate short-lived sedimentation pulses, and enhance particle–particle interactions even when mean concentrations are low. We investigate these processes using controlled laboratory experiments that isolate clustering and its effects in sustained, free-falling columns of volcanic ash. We vary particle size distributions and mass release rates to span particle volume fractions ≈10-5–10-2, encompassing conditions relevant to dispersing clouds and ash-laden regions within PDCs. High-speed laser imaging and particle tracking resolve instantaneous particle positions and velocities. We quantify clustering with Voronoi tessellation, measure settling velocity variability, and estimate a collision-rate proxy from local particle statistics to link spatial organisation to encounter likelihood. Results suggest that clustering can create strong local concentration contrasts, whose intensity can enhance particle–particle interactions and increase the potential for collisions, aggregation, and turbulence-modulated settling. Importantly, peaks in the collision-rate proxy are not explained by velocity variability alone, indicating that spatial organisation shortens effective interaction length scales and increases encounter frequency. These findings link dilute turbulent suspensions to enhanced fallout and collision/aggregation potential, and they highlight the need for hazard models to capture local concentration contrasts, not just bulk-mean concentrations.
How to cite: Capponi, A., Cimarelli, C., and Mininni, P.: Settling, Swirling, Sticking: Clustering-Driven Interactions In Volcanic Particle Flows, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5338, https://doi.org/10.5194/egusphere-egu26-5338, 2026.
The first step towards mitigating the risks associated with pyroclastic density currents (PDCs) consists in quantifying the probability of their occurrence through probabilistic hazard studies. The Island of Ischia constitutes the emerged portion of a large volcanic system, known as the Ischia Volcanic Field (IVF). The last eruption, which occurred in AD 1302, was preceded by centuries of intense volcanic activity, with more than 30 eruptions in the last 10,000 years. At present, the Ischia system is quiescent, but new magmatic intrusions could trigger renewed resurgence, seismic activity and slope instability, potentially culminating in volcanism. The island hosts a permanent population of approximately 60,000 inhabitants, which increases dramatically during summer. This demographic context highlights the urgency of quantitatively assessing volcanic hazards on the island, a topic still poorly addressed in the literature. The aim of this work is to quantify the hazard related to the invasion by PDC on Ischia. We adopted two alternative simplified modeling frameworks (the Energy Cone and the Box model) to study all known explosive eruptions of over the past 10 ky. For each eruption we inverted for potential source parameters and investigated their possible correlations. Vent location uncertainty was addressed adopting a kernel approach based on the spatial distribution of active vents during the past 10 ky. By integrating uncertainties in vent location with dimensional variability of currents, we quantified the hazard associated with PDCs both conditionally, given the occurrence of an eruption, and unconditionally, by estimating the probability of invasion within the next century. This analysis provides a first quantitative estimate of the probabilistic hazard associated with pyroclastic flows for Ischia and demonstrates that the highest probabilities are found in densely populated areas, especially in the area of Casamicciola Terme, Ischia Porto, and Barano. Conditional probability of PDC invasion above 5% includes those areas as well as parts of the NW and SW sectors of the island, between Forio, Panza, and Lacco Ameno, including most of the main populated areas.
How to cite: Marfella, D. E., de Vita, S., Macedonio, G., Sansivero, F., and Selva, J.: Probabilistic assessment of hazard related to pyroclastic currents at Ischia, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-5712, https://doi.org/10.5194/egusphere-egu26-5712, 2026.
Pyroclastic Density Currents (PDCs) can be generated by explosive eruptions or by gravitational flank collapses involving unstable volcanic material (e.g., lava fronts, crater rims, domes). While the distribution of block-and-ash flow deposits is topographically confined to the transport and accumulation basin, these phenomena are frequently associated with co-PDC ash clouds. These buoyant clouds, composed of fine particles elutriated from the flow, spread over wider areas and settle as thin fallout layers. The recognition of such widely distributed layers enables the tephrostratigraphic investigation of historical collapse events, which are often under-recorded in the geological record.
At Stromboli, a direct link between pinkish tephra layers and partial flank collapses was established through the observation and syn-emplacement sampling of the ash cloud generated by the 19 May 2021 crater rim collapse (Re et al., 2022). Analogous deposits, previously described in the stratigraphic record (Bertagnini et al., 2011; Rosi et al., 2019; Pistolesi et al., 2020), have been repeatedly observed in recent activity (e.g., July 2024), indicating that such collapses represent a recurrent phenomenon.
Here, we present the study, conducted in the framework of the REFLeCTS project (INGV), of a stratigraphic sequence found on the northern side of the San Bartolo lava flow, dating back to Greek-Roman times (360 BC - 7 AD; Speranza et al., 2008). This succession consists of alternating ash and lapilli fallout beds related to typical Strombolian activity, interspersed with several relatively thick (from few mm to 5 cm) pink ash layers. Given that the limited thickness of these layers and the highly dynamic environment of active volcano flanks usually lead to their rapid obliteration by erosion or burial, the exceptional preservation of these tephra layers offers a unique opportunity to assess the recurrence of flank collapse events during Stromboli's recent eruptive history.
How to cite: Re, G. and Pompilio, M.: Pinkish ash layers as fingerprints of flank instability: Unveiling Stromboli’s collapse recurrence through tephrostratigraphy, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11058, 2026.
Water-laden sedimentary archives, such as marine and lacustrine sequences, have revolutionised the reconstruction of eruptive histories, as they usually hold a richer and more continuous tephra record when compared to subaerial environments. Here, we explore peatlands as another sedimentary archive from which highly detailed tephrostratigraphies can be obtained. Peat sequences have the advantage of being logistically easier and cheaper to access than other water-laden sequences, and more readily amenable to radiocarbon dating than terrestrial sequences. Pico Island in the Azores Archipelago provides an ideal laboratory to test the potential of peatlands as high-resolution sedimentary archives. The island is characterised by numerous basaltic monogenetic cones, yet its tephrostratigraphy remains poorly constrained, as such eruptions typically generate small tephra dispersals, and the resulting deposits are difficult to date. Taking advantage of the ubiquitous peatlands found in the Pico central uplands (above ~600 m altitude), a coring campaign was carried out in July 2025. Eight peatlands were cored using a Russian corer and a UWITEC® piston corer installed on a platform raft. Peatland basins were surveyed using a DJI Mavic 2 drone to produce high-resolution georeferenced digital surface models. Recovered cores were opened and logged at the University of the Azores, where peat, lacustrine, and volcanic facies (tephra horizons) were identified. Loss on ignition (LOI) was determined throughout the sedimentary sequences, and their bases were radiocarbon dated. Here, we present the stratigraphic sequences of the four main peatlands: Caiado and Barreira cone craters, and Peixinho and Lavandeira inter-cone depressions. All four stratigraphic sequences contain numerous tephra horizons, ranging in thickness from less than 1 mm up to several tens of centimetres. The thickest tephra horizons are found at the sites located in the eastern sector (Peixinho and Caiado), whereas thinner horizons predominate at the western sites (Lavandeira and Barreira). Most tephra horizons correspond to primary fall deposits, with only a minor portion of reworked materials. Radiocarbon dating reveals maximum sequence ages of 8608-8514 cal yr BP (Caiado), 6558-6399 cal yr BP (Lavandeira), 5588-5474 cal yr BP (Barreira), and 2181-2046 cal yr BP (Peixinho). The bases of the Barreira and Caiado sequences consist of weathered subaerial scoria deposits, interpreted as pre-lacustrine substrate. Lower LOI values, typically found in the lower part of the sequences, suggest initial lacustrine conditions, whereas higher LOI values in the upper part of the records indicate the transition to peatland. Ongoing work will focus on systematic radiocarbon dating below primary tephra horizons and geochemical characterisation of volcanic glass shards, enabling a high-resolution temporal and spatial reconstruction of Pico’s Holocene eruptive history. This work was supported by Fundação para a Ciência e a Tecnologia (FCT) through project ExTRAP (https://doi.org/10.54499/2023.12382.PEX).
How to cite: Pimentel, A., Souto, M., Raposeiro, P., Ramalho, R., Hernández, A., Andrade, M., Gonçalves, V., Giralt, S., Trigo, R., Matias, M., Schindlbeck-Belo, J., Pacheco, J., and Sáez, A.: Peatlands as high-resolution sedimentary archives of Holocene tephrostratigraphy on Pico Island (Azores): preliminary results, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11883, 2026.
Mount Erciyes, the largest active volcano of Central Anatolia (Turkey), erupted explosively during the Holocene, producing the Karagüllü, Perikartin, and Dikkartin rhyolitic tuff rings. These eruptions occurred along regional fault systems and were partially destroyed by subsequent lava domes at the end of the phreatomagmatic phases, generating block-and-ash flows. Despite the proximity of major urban areas such as Kayseri (~1 million inhabitants), the timing, magnitude, and eruptive sequence of these explosive events have remained poorly constrained, as previous cosmogenic and radiogenic dating attempts lacked sufficient precision to resolve their chronology. To improve the Holocene explosive eruptive history of Mount Erciyes and assess regional ash dispersal, we integrate detailed tephrostratigraphic observations, glass shard geochemistry (major and trace elements), and radiocarbon dating of organic-rich paleosols. Our results indicate that the Karagüllü tuff ring formed at 11,258 ± 56 cal BP, followed by the Perikartin eruption at 9,700 ± 100 cal BP. Although no clear stratigraphic contacts or datable paleosols were identified for Dikkartin, its glass composition closely matches the regional Mediterranean S1 tephra, dated to approximately 9 ka BP. Distal correlations confirm the presence of Karagüllü tephra in the Black Sea tephra and Romanian lake records, indicating that Central Anatolian eruptions dispersed volcanic ash over several hundred to more than a thousand kilometres across Europe and the eastern Mediterranean during the early Holocene. Trace element data further support a distal dispersal of Dikkartin and Perikartin ashes to the Mediterranean basin. While Dikkartin has been classified as a Plinian eruption, the possibility of near-synchronous eruptive activity between Dikkartin and Perikartin cannot be excluded. These results refine the regional tephrochronological framework and underscore the need to reassess volcanic hazards in Central Turkey and surrounding regions.
This work was funded by the Spanish Ministry of Science and Innovation (TURVO, PID2023-147255NB-I00; MCIN/AEI/10.13039/501100011033), the EU (ERDF; Horizon 2020–MSCA PÜSKÜRÜM, Grant 101024337), and the Italian PNRR–NextGenerationEU through the ÇoraDrill project (CUP B83C25001180001).
How to cite: Sunyé-Puchol, I., Özsoy-Ünal, R., Bolós, X., Smith, V. C., Akkas, E., Tavazzani, L., Aymerich, J., Nazzari, M., Lacan, P., Bachmann, O., Scarlato, P., and Mollo, S.: Eruptive history of Holocene explosive activity at Erciyes volcano (Turkey) constrained by proximal and distal tephra records, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11893, 2026.
Electrical activity, including visible lightning, has been observed at Stromboli (Italy) during various eruptive scenarios and has also been reported in association with the emplacement of pyroclastic density currents (PDCs). The multiparametric monitoring network operating at Stromboli enables a detailed investigation of PDCs generated by a range of eruptive and gravitational processes, including column collapse during paroxysmal eruptions, crumbling of lava overflows, and collapses of the crater rim or flank. Previous analyses of the electrical activity at Stromboli have primarily focused on paroxysmal eruptions during which PDCs concurrently occurred, making it difficult to isolate and interpret electrical signatures generated by PDCs alone. PDCs generated by gravitational instabilities of volcaniclastic deposits, located on the crater rim or volcano flanks, offer a unique opportunity to investigate their electrical signatures in the absence of an eruptive column and other relevant syn-explosive processes. Here, we present analyses of electrical signals recorded during the occurrence of deposit-derived PDCs propagating along Sciara del Fuoco. Electrical activity was measured using a lightning detector deployed in close proximity to the flow pathway to monitor changes in the ambient electric field. Complementary thermal and visual imaging of the crater area and flow path enables correlation of the electrical signal variation with the timing, evolution, and spatial extent of the PDC events. We compare these observations with electrical signals recorded during eruptive activity at Stromboli involving sustained eruptive columns, to assess the similarities and differences between column-collapse PDCs and eruption-driven electrical signatures. Distinguishing different types of volcanic phenomena solely based on their electric signature offers a complementary approach for volcano monitoring, enabling the rapid detection of PDC occurrence and aiding the classification of explosive activity.
How to cite: Poetsch, C., Cimarelli, C., Capponi, A., Di Traglia, F., and Bennett, A. J.: Electrical Signals Generated by Pyroclastic Density Currents at Stromboli Volcano, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14159, 2026.
Pyroclastic density currents (PDCs) are mixtures of volcanic particles and gas that flow down the flanks of volcanoes, guided to some degree by the morphology. They are the deadliest and most destructive volcanic phenomena, primarily due to their mobility and unpredictability. Mechanical interaction of clasts during transport produces fines through abrasion and comminution. The ash content is believed to have a positive influence on mobility, however, the in-situ production of ash in PDCs is still poorly quantified.
Three different types of experiments (T1, T2, T3B), each starting with 2 kg angular pumice lapilli from the Laacher See (Eifel, Germany) eruption at 12,900 a BP, were conducted to gain a better understanding of ash production rates and related lapilli clast shape changes (Figueiredo et al., 2025). Every set of experiments eventually tumbled the lapilli for 120 minutes. At five time increments (15’, 30’, 45’, 60’, 120’) the drum load was dry sieved at 2 mm. For T1 experiments, ash and lapilli were returned to the drum after each time step. In experiments T2 and T3B, the ash was stored separately, and only the lapilli fraction was returned to the drum. In experiment T3B, steel balls (220 g each) were added to simulate dense blocks.
The amount of ash produced analysed after each tumbling step was plotted as weight fraction of the starting load. To understand fine generation better, the ash was analysed by dry sieving at half-φ and laser diffraction analysis. For all three experiments, ash generation efficiency is negatively correlated with tumbling time, with T1 producing the smallest and T3B the highest amount of ash (as high as 47 wt.%). Noteworthy is the production of up to 18,20 wt.% of fine ash (<63 µm) and 2,83 wt.% of PM10 (≤10 μm) relative to the initial starting weight. These numbers are surprisingly high given the comparatively short and low-energy experiments. Accordingly, uninterrupted abrasion and comminution during PDC transport is a quasi-infinite source of ash supply, influencing PDC flow conditions and mobility and should be considered in future PDC runout and health impact models.
Reference: Figueiredo, C., Kueppers, U., Pereira, L. et al. Shape evolution of pumice during granular flow. Commun Earth Environ 6, 941 (2025). https://doi.org/10.1038/s43247-025-02936-4
How to cite: Kueppers, U., Bauer, S., Figueiredo, C., and Beyer, U.: Making dust: The easy way of generating (a lot of) fine ash during tumbling experiments, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14211, 2026.
Nearly 20 million people live within a100 km radius from Popocatepetl volcano in central. Mexico. Ashfall is frequent since emissions began in 1994. Ash is sampled weekly or daily depending on the activity. A 200 site ash monitoring network is enhanced by community participation and reports. Negative magnetic anomalies (WD 5nT) during March and April 2023, September 2024 and during the first 4 days in April 2025 were correlated with harmonic tremor and small chemical changes in the springwater near the volcano. These precursors preceded abundant ash emission in 2023 and 2024 by 2 month and small ash emissions in 2025 and 2026. This allowed us to advice Civil Protection weeks before and get the population prepared with facemasks and get school protocols into place. The Mexico City and Puebla international airports were closed for 2 days in 2023 and bad road visibility due to the fine ash caused serious transportation problems. Crops were also affected but only minor respiratory health problems occurred. Ash composition varied from 58- 60 SiO2 % in 2023 and from 59 -61 SiO2 % in 2024. Smaller amounts of ash in 2025 and 2026 are associated with the formation of small lava domes while the larger emissions result from a constant ash emission over several days.
How to cite: Martin Del Pozzo, A. L., González Hernández, S. K., Díaz Cruz, M. A., Sandoval García, M., and Cifuentes Nava, G.: Precursors to Tephra Emission, Variation and Dispersal at Popocatepetl Volcano (Mexico), 2023-2026 , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15135, 2026.
Pyroclastic Density Currents (PDCs) are deadly, highly destructive, fast-moving, ground-hugging, mixtures of hot gas and volcanic particles. PDC high velocities, dynamic pressures, and temperatures make direct field measurements extremely challenging. Due to the combination of high-impact to the natural and built environment, and the difficulty of obtaining direct measurements, remote detection methods would be of benefit to their study and early warning systems. Acoustic methods have been proposed in the past for this application, however, due to sparse field data, there remains a limited understanding of the fundamental question regarding the source of the recorded acoustic signals. The Pyroclastic flow Eruption Large-scale Experiment (PELE) is a large-scale experimental facility designed to synthesize pyroclastic density currents (PDCs) within a laboratory environment. PELE has been augmented with acoustic sensors allowing for the direct observation of physical properties and the location of the experimental flow with time-synchronized acoustic data.This study examines the location and source of the acoustic signals that have been previously identified in field data. Combining signal cross-correlation between sensors with known offsets within the experimental channel, and high speed imaging of the experimental flow, the resulting dataset showed that there are multiple pulses of signal sources within a single flow. These signals seem to be associated with the interface of the flow and the atmosphere. This result highlights that, while previously the source of the field signals was attributed to the front of the flow, there are multiple sources within the flow. Further research should be undertaken to further explore the role of these different sources and topography and path in the field. Additionally, this insight should be taken into account for sensor deployment design and early warning system development.
How to cite: Perttu, A., Lube, G., Jellinek, M., Ichihara, M., Robert, J., and Brosch, E.: Insights into Acoustic Sources from Pyroclastic Density Currents , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16597, 2026.
Campi Flegrei caldera (CFc) is one of the most hazardous volcanic systems in Europe, with over 1.2 million people in Naples living within 10 km of the active volcano and the neighbouring volcanoes of Ischia, Procida, and Somma-Vesuvius[1]. Constraining the explosive eruptive history of CFc is critical for understanding future volcanic hazards. Over the past 40 kyr, three caldera-forming eruptions have occurred at CFc: the Campanian Ignimbrite (CI; 40 ka[2]), the Masseria del Monte Tuff (MdMT; 29.3 ka[3]) and the Neapolitan Yellow Tuff (NYT; 14.9 ka[4]). Whilst these major events are well characterised, smaller eruptions between them remain poorly constrained in magnitude and time despite representing key phases in the magmatic evolution of CFc. Few proximal sections preserve a detailed record of eruption deposits from the interval between the CI and NYT.
We present new detailed field and glass geochemical data from Monte di Procida, southwest of CFc, which records 21 tephra units, including the CI and NYT. This represents the most complete CI–NYT sequence identified to date. Three main CFc compositional subgroups are recognised: (i) a dominant NYT-like trachytic melt (~60 wt.% SiO₂) with limited variability, (ii) a more evolved trachytic subgroup (~64 wt.% SiO₂), and (iii) a trachybasaltic composition (~55 wt.% SiO₂). The section also contains distinct Solchiaro (~23 ka[5]) tephras from Procida, separated by an Ischia-derived ash, evidencing contemporaneous activity during this interval across the Campanian Volcanic Zone. These data reveal that at least 15 of the eruption deposits are from CFc, indicating a higher pre-NYT eruptive tempo than previously recognised.
The Monte di Procida record reveals greater activity with 11 eruptions in the 9 kyr preceding the NYT eruption, suggesting frequent activity in the build-up to the NYT caldera-forming eruption. Inter-eruption glass compositions show similar chemical signatures with limited variability in major and trace elements, complicating the use of tephras from this record in wider regional correlations.
References:
1. Meredith et al. (2025) Nat. Hazards Earth Syst. Sci. 25: 2731-2749.
2. Giaccio et al. (2017) Sci. Rep. 7: 45940.
3. Albert et al. (2019) Geology. 47: 595-599.
4. Deino et al. (2004) JVGR. 133: 157-170.
5. Morabito et al. (2014) Glob. Plan. Change 123: 121-138.
How to cite: Kane, G., Natale, J., Isaia, R., Stock, M., Teixeira, L., Tomlinson, E. L., and Smith, V. C.: Insights into eruption activity between recent caldera-forming eruptions at Campi Flegrei caldera (southern Italy): A Detailed Tephrostratigraphic Record from Monte di Procida., EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17012, 2026.
Stromboli volcano, Italy, is characterized by persistent explosive activity occasionally punctuated by more energetic explosions, called paroxysms, during which deposit-derived pyroclastic density currents (PDCs) may be generated by the gravitational instability of hot, unstable pyroclastic deposits. Although typically confined within the Sciara del Fuoco, a prominent depression on the volcano’s NW flank, historical events such as the 1930 and 1944 paroxysms demonstrate that these flows can propagate beyond this depression, posing a significant hazard to inhabited areas and climbers.
This study combines the reconstruction of a well-documented historical event with a probabilistic hazard assessment to evaluate the potential impact of deposit-derived PDCs over the entire island. The September 11, 1930 paroxysm is reanalyzed by integrating new field observations, historical records, and numerical modeling, providing a test case for model calibration and a first probabilistic reconstruction of the phenomenon. Recent erosive floods exposed previously unrecognized PDC deposits in the San Bartolo valley, complementing those identified in the Vallonazzo basin. These new data, together with eyewitness accounts, were used to constrain maximum flow thicknesses along the valleys. A shallow-water dense granular flow model coupled with an inversion algorithm indicates that the PDC propagated mainly within these valleys, with limited secondary flows in adjacent basins. Consistently with field evidence, the Vallonazzo flow reached the sea, whereas the San Bartolo flow stopped near the local church, with an estimated total remobilized volume between 34,000 and 59,000 m³. Results also highlight the strong dependence of invaded areas on the location of the source material.
Building on this calibration, a new probabilistic framework based on random circular sector source models is applied to assess PDC hazard at the scale of the island. Six main drainage basins with significant hazard potential were identified. Among these, San Bartolo, Scalo dei Balordi, and Ginostra “A” show the highest conditional invasion probabilities, while other inhabited valleys exhibit lower but still non-negligible values. By coupling spatial invasion probabilities with a temporal occurrence model linking paroxysm frequency to PDC generation, we estimate a substantial probability of future PDC invasion outside the Sciara del Fuoco over decadal to multi-decadal timescales, despite the large uncertainties associated with the limited historical record.
How to cite: Neri, A., Bevilacqua, A., Geddo, Z., Corna, L., Di Roberto, A., Di Traglia, F., Pompilio, M., Bertagnini, A., de'Michieli Vitturi, M., Flandoli, F., and Tadini, A.: Deposit-derived pyroclastic density currents at Stromboli: from the 1930 event reconstruction to probabilistic hazard assessment, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17226, 2026.
