Volcanic Ash Fallout Research Articles

Occurrence of an unknown Atlantic eruption in the Chaîne des Puys volcanic field (Massif Central, France)

A volcanic ash layer, called MF1, was recently identified in Holocene sediments from the Gourgon and Molhiac peat bogs (Monts du Forez, French Massif Central). This ash layer consists of colorless shards with a heterogeneous trachytic to rhyolitic composition. The trace elements analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) attest to a local origin. Radiocarbon dating of peat samples taken within and below the ash layer indicates the best age at 6339±61calyrBP, i.e. an age contemporaneous with the volcanic activity of Montchal, Montcineyre and Pavin volcanoes from the Chaîne des Puys volcanic field. These volcanoes are characterized by basaltic and trachytic products, thus the rhyolitic composition of MF1 tephra suggests that it is likely originated from an unknown eruption. These results again confirm the interest of studying the distal volcanic ash fallouts in order to establish or specify records of past eruptions of volcanic fields. Identification of this new tephra layer also provides an additional tephrochronological marker for Eastern French Massif Central.

United theory of biological evolution: Disaster-forced evolution through Supernova, radioactive ash fall-outs, genome instability, and mass extinctions

We present the disaster-forced biological evolution model as a general framework that includes Darwinian “phylogenic gradualism”, Eldredge-Gould's “punctuated equilibrium”, mass extinctions, and allopatric, parapatric, and sympatric speciation. It describes how reproductive isolation of organisms is established through global disasters due to supernova encounters and local disasters due to radioactive volcanic ash fall-outs by continental alkaline volcanism. Our new evolution model uniquely highlights three major factors of disaster-forced speciation: enhanced mutation rate by higher natural radiation level, smaller population size, and shrunken habitat size (i.e., isolation among the individual populations). We developed a mathematical model describing speciation of a half-isolated group from a parental group, taking into account the population size (Ne), immigration rate (m), and mutation rate (μ). The model gives a quantitative estimate of the speciation, which is consistent with the observations of speciation speed. For example, the speciation takes at least 105 generations, if mutation rate is less than 10−3 per generation per individual. This result is consistent with the previous studies, in which μ is assumed to be 10−3–10−5. On the other hand, the speciation is much faster (less than 105 generations) for the case that μ is as large as 0.1 in parapatric conditions (m ＜ μ). Even a sympatric (m ～ 1) speciation can occur within 103 generations, if mutation rate is very high (μ ～ 1 mutation per individual per generation), and if Ne ＜ 20–30. Such a high mutation rate is possible during global disasters due to supernova encounters and local disasters due to radioactive ash fall-outs. They raise natural radiation level by a factor of 100–1000. Such rapid speciation events can also contribute to macro-evolution during mass extinction events, such as observed during the Cambrian explosion of biodiversity. A similar rapid speciation (though in a much smaller scale) also has been undergoing in cichlid fishes and great African apes in the last several tens of thousand years in the current African rift valley, including the origin of humankind due to the radioactive ash fall-outs by continental alkaline volcanism.

Potential Damages of Atmospheric Storage Tanks due to Volcanic Ash Aggregations in Presence of Water

Recent studies of the effects of the volcanic ash fallout on storage tanks have shown the potential causes of failure for both fixed and floating roof tanks. The vulnerability of these facilities has been defined through the estimation of threshold values of the ash load on their roofs and exceedance probabilities of these limits. It has been observed that the amount of the overhead on the roof is much greater when the ash is saturated with rain because of the formation of aggregates. This paper aims to analyse the influence of this phenomenon on the potential damage of tanks located in the area surrounding Mt. Etna.

Volcanic ash in the air we breathe

Volcanic ash in the air we breathe

Vulnerability Assessment for Human Targets due to Ash Fallout From Mt. Etna

The volcanic ash fallouts are able to affect the human health and the integrity of industrial facilities. The study of the effects associated with ash emissions was the objective of the PRIN project carried on by the authors of this paper. The activities of the project allowed to define a simplified procedure for the vulnerability assessment of human and industrial targets, that has been applied to the area surrounding Mt. Etna. Recent several ash fallouts from this volcano have caused significant problems to the resident population, traffic and industrial activities. The application of the study to this territory provided a vulnerability mapping to support the decision making both in terms of the definition of protection measures and of the emergency planning and management.

Risks associated with volcanic ash fallout from Mt.Etna with reference to industrial filtration systems

The recent eruption of the Icelandic volcano has focused the worldwide attention on volcanic ash effects for the population, road, rail and air traffic and production activities. This paper aims to study of technological (industrial) accidental scenarios triggered by ash fallout and, more specifically, to define and quantify the potential damage on filtration systems. Malfunctions due to the filter clogging and service interruptions caused by the rupture of the filtering surface have been analysed in order to define the vulnerability of the equipment to such damages. Results are given in terms of threshold values of deposit on the filtering surface and exceedance probability curves of ash concentrations and the duration of the ash emission. This data can be easily implemented in the standard risk assessment with the aim to include the estimation of Natural-Technological (Na-Tech) hazards.

Possible impacts of volcanic ash emissions of Mount Etna on the primary productivity in the oligotrophic Mediterranean Sea: Results from nutrient-release experiments in seawater

Atmospheric deposition of volcanic ash has recently been recognized as an important nutrient source into the surface ocean. Mount Etna (Italy), one of the world's most active volcanoes, is located in the oligotrophic Mediterranean Sea (MedSea). Despite the active volcanism on Mount Etna, the biogeochemical impacts of volcanic ash fallouts on the marine primary productivity (MPP) remain largely unknown. Here we present the results of seawater nutrient release experiments with volcanic ash samples from Mount Etna that have been collected during different eruptive episodes between 2001 and 2007. Our results show that volcanic ash from Mount Etna releases significant amounts of fixed-N (35–855nmol/g), P (7–970nmol/g), Si (3–2060nmol/g), Fe (10–130nmol/g) and Zn (<21nmol/g). We further estimated an example representative of ash-fall from Etna based on the case-study focusing on 4–5 November 2002 activity, by using the general relation between the thicknesses of the ash deposits and the ash depositional areas. Etna explosive eruptions can transport volcanic ash as far as 800km, with ash emissions exceeding the particle flux during dust storm events (of 10g/m2 input) as far as 400km downwind from the volcano. Our results emphasize that Etna ash can provide a significant supply of nutrients, which can favor the MPP in the central MedSea.

Potential loading damage to industrial storage tanks due to volcanic ash fallout

The phenomenon of volcanic fallout ash from Mt. Etna in Sicily (Italy) is well known and frequent in recent years, as in the period 2001–2004. As a consequence, significant problems for the population, road, rail and air traffic and production activities have occurred. The industrial areas of Catania and Augusta-Priolo, located in south eastern Sicily, might be involved during particular weather conditions. This paper aims at determining the potential scenarios of damage to industrial facilities caused by volcanic ash fallout. The work has been focused on the study of both fixed and floating roof storage tanks, containing flammable liquids, and examines extreme failures damage causing the greatest loss of containment for these facilities. To include scenarios arising from natural phenomena (Na-Tech events) in the standard risk assessment procedure, the estimation of the vulnerability of these facilities is necessary. The study has been applied to the area surrounding Mt. Etna, and the procedure can also be extended to other case studies.

Environmental changes across the Triassic–Jurassic boundary and coeval volcanism inferred from elemental geochemistry and mineralogy in the Kendlbachgraben section (Northern Calcareous Alps, Austria)

The end-Triassic extinction (ETE), one of the five largest Phanerozoic mass extinctions, is associated with rapid and severe environmental change, but existing data permit alternative models of causation. Volcanism in the Central Atlantic Magmatic Province (CAMP) has been proposed as the main trigger, but direct evidence for this linkage is scarce. To help constrain scenarios for the ETE and other Triassic–Jurassic boundary (TJB) events, we obtained a temporally highly resolved, multidisciplinary dataset from the Kendlbachgraben section in the Northern Calcareous Alps in Austria. The section belongs to the same paleogeographic unit (Eiberg Basin) and share similar stratigraphy with the recently selected base Jurassic Global Stratotype Section and Point at Kuhjoch.Micromineralogic study of the topmost bed of the Rhaetian Kössen Formation revealed pseudomorphs of altered, euhedral pyroxene and amphibole crystals. Their well-faceted morphology is consistent with their origin from distal mafic volcanic ash fallout. Spherical grains were also observed in the same bed, likely representing clay-altered volcanic glass. Clay minerals of this bed include low- to medium-charged smectite and Mg-vermiculite, both typical alteration products of mafic rocks. The same bed yielded a rare earth element pattern that differs from all other levels in an enrichment of heavy REEs, hinting at some minor contribution from mafic magmatic material. These features from a layer that was deposited very near to the TJB are interpreted as direct evidence of CAMP volcanism, coeval or immediately preceding the ETE and the initial negative carbon isotope anomaly.The kaolinite-dominated clay mineral spectrum of the overlying boundary mudstone records intensive weathering under hot and humid greenhouse conditions. Redox-sensitive minor and trace elements do not support the development of widespread anoxia in the studied section. Although pyrite is common in several layers, framboid size indicates formation within a reductive zone, below the sediment/water interface, rather than in an anoxic water column.Our data provide a direct link between uppermost Triassic marine strata and CAMP-derived material. They support scenarios where CAMP volcanism induced climate and other environmental change, which in turn triggered the ETE and that is also reflected in the carbon isotope anomalies.

Long-range volcanic ash transport and fallout during the 2008 eruption of Chaitén volcano, Chile

The May 2008 eruption of Chaitén volcano, Chile, provided a rare opportunity to measure the long-range transport of volcanic emissions and characteristics of a widely-dispersed terrestrial ash deposit. Airborne ash mass, quantified using thermal infrared satellite remote sensing, ranged between 0.2 and 0.4Tg during the period 3–7 May 2008. A high level of spatiotemporal correspondence was observed between cloud trajectories and changes in surface reflectivity, which was inferred to indicate ash deposition. The evolution of the deposit was mapped for the first time using satellite-based observations of surface reflectivity.The distal (>80km) ash deposit was poorly sorted and fine grained, and mean particle size varied very little beyond a distance >300km. There were three particle size subpopulations in fallout at distances >300km which mirror those identified in fallout from the 18 May 1980 eruption of Mount St. Helens, known to have a high propensity for aggregation. Discrete temporal sampling and characterisation of fallout demonstrated contributions from specific eruptive phases. Samples collected at the time of deposition were compared to bulk samples collected months after deposition and provided some evidence for winnowing.Experimentally-derived ash leachates had near-neutral pH values and charge balance which indicates minimal quantities of adsorbed acids. X-ray Photoelectron Spectroscopy (XPS) analyses revealed surface enrichments in Ca, Na and Fe and the presence of coatings of mixed Ca-, Na- and Fe-rich salts on ash particles prior to deposition. Low S:Cl ratios in leachates indicate that the eruption had a low S content, and high Cl:F ratios imply gas–ash interaction within a Cl-rich environment. We estimate that ash fallout had potential to scavenge ∼42% of total S released into the atmosphere prior to deposition. XPS analyses also revealed ash particle surfaces were strongly enriched in Fe (in contrast to the results from bulk leachate analyses), which suggests that Chaitén ash fallout over oceans had potential to influence productivity in high-nutrient, low-chlorophyl regions of the oceans. Therefore ash particle surface geochemical analysis should be applied to quantify Fe-modulated biologically-forced CO2 draw-down potential of volcanic ash fallout over oceans.

Tephra fallout hazard assessment for a Plinian eruption scenario at Volcán de Colima (Mexico)

Volcanic ash fallout associated with renewal of explosive activity at Colima, represents a serious threat to the surrounding urbanized area. Here we assess the tephra fallout hazard associated with a Plinian eruption scenario. The eruptive history of Volcán de Colima shows that Plinian eruptions occur approximately every 100 years and the last eruption, the 1913, represents the largest historic eruption of this volcano. We used the last eruption as a reference to discuss volcanic hazard and risk scenarios connected with ash fallout. Tephra fallout deposits are modeled using HAZMAP, a model based on a semi-analytical solution of the advection–diffusion–sedimentation equation for volcanic particles. Based on a statistical study of wind profiles at Colima region, we first reconstructed ash loading maps and then computed ground load probability maps for different seasons. The obtained results show that a Plinian eruptive scenario at Volcán de Colima, could seriously damage more than 10 small towns and ranches, and potentially affect big cities located at tens of kilometers from the eruptive center. The probability maps obtained are aimed to give support to the risk mitigation strategies.

Paleoenvironments of Kuril Islands in Late Pleistocene–Holocene: Climatic changes and volcanic eruption effects

The Kuril Islands are noted for a variety of landscapes, from nemoral broadleaf forests to forest-tundra and tundra. Some large islands display a distinct altitudinal zonality. Environments of the islands bear evidence of various catastrophic events that controlled the landscape evolution to a considerable extent. Changes of climate during the Pleistocene were of particular importance in evolution of the environments. Dramatic rapid fluctuations of climate at the Late Pleistocene–Holocene boundary resulted in repeated restructuring of landscapes at the land bridge connecting the South Kuriles and Hokkaido. In the southern part of the Small Kuril Ridge open forests might persist until the land mass was broken into small islands dominated by meadow–marsh vegetation since the Middle Holocene. On the Central and Northern Kuril Islands, environmental changes during the Middle and Late Holocene resulted both from climatic fluctuations and from repeated fallout of volcanic ash. Deposition of organic matter began about 6.5 ka BP. It resulted from the onset of more favorable conditions, namely warming, increase of moisture supply and reduction of volcanic activity. The evolution of island landscapes consisted mainly in changes of relative area occupied by various plant communities, most of which are present in modern vegetation. The Holocene climatic optimum was not particularly pronounced in this part of the Great Kuril Ridge. Some consideration is given to issues of changes in zonal boundaries at different time intervals within Late Pleistocene and Holocene.

Aerosol measurements from a recent Alaskan volcanic eruption: Implications for volcanic ash transport predictions

Size and time-resolved aerosol compositional measurements conducted during the 2006 eruption of Augustine Volcano provide quantitative information on the size and concentration of the fine volcanic ash emitted during the eruption and carried and deposited downwind. These data can be used as a starting point to attempt to validate volcanic ash transport models. For the 2006 eruption of Augustine Volcano, an island volcano in south-central Alaska, size and time-resolved aerosol measurements were made using an eight-stage (0.09–0.26, 0.26–0.34, 0.34–0.56, 0.56–0.75, 0.75–1.15, 1.15–2.5, 2.5–5.0, and 5.0–35.0 μm in aerodynamic diameter) Davis Rotating Unit for Monitoring (DRUM) aerosol impactor deployed near ground level in Homer, Alaska, approximately 110 km east–northeast of the volcano. The aerosol samples collected by the DRUM impactor were analyzed for mass and elemental composition every 90 min during a four-week sampling period from January 13 to February 11, 2006, that spanned several explosive episodes during the 2006 eruption. The collected aerosols showed that the size distribution of the volcanic ash fallout changed during this period of eruption. Ash had its highest concentrations in the largest size fraction (5.0–35.0 μm) with no ash present in the less than 1.15 μm size fractions during the short-lived explosive events. In contrast, during the continuous ash emission phase, concentrations of volcanic ash were more significant in the less than 1.15 μm size fractions. Settling velocities dictate that the smaller size particles will transport far from the volcano and, unlike the larger particles, not be retained in the proximal stratigraphic record. These results show that volcanic ash transport and dispersion (VATD) model predictions based on massless tracer particles, such as the predictions from the PUFF VATD model, provide a good first-order approximation of the transport of both large and small volcanic ash particles. Unfortunately, the concentration of particles in different size fractions depends on eruptive style and ash generation processes, so predicting the actual behavior of the ash particles from an eruption requires additional information in real time.

Develop instruments to monitor volcanic ash fallout

Develop instruments to monitor volcanic ash fallout

Change of landscape structure of Matua Island after the Sarichev Volcano Peak Eruption June 12–15, 2009

Due to the Sarichev volcano peak eruption June 12–15, 2009, the landscape of Matua Island was modified greatly. On the basis of field data, the spatial structure of the island landscape before and after eruption was analyzed. Scale maps 1: 200 000 reflecting the landscape structure of the island before June 12 and on June 30 are presented. It was established that the landscape on the slope of the volcano cone was essentially restructured by the influence of pyroclastic flows and volcanic ash fall-out. Complication of the island structure was noted after the volcanic eruption.

Tephrochronological study in the quaternary Val d’Agri intermontane basin (Southern Apennines, Italy)

In the south-eastern depocentre of the Val d’Agri basin (Southern Apennines), a volcanic ash layer crops out interbedded within poorly structured alluvial fan deposits of Late Pleistocene age. Textural, depositional and pedological features of this weathered layer suggest a primary deposition from a pyroclastic fall-out of volcanic ash. Chemical analyses of feldspars show an alkali trachytic composition and accessory minerals association allow to correlate this tephra layer with the regionally dispersed Y-7 marine tephra layer (Tufo Verde Epomeo eruption, Ischia volcano), dated at 56 ± 4 ka. The Val d’Agri tephra here described for the first time was deposited during MIS Stage 3. Its recovery and characterization permit to contribute to regional correlation of the Mediterranean climatic and volcanic events from marine to continental successions and to describe landscape evolution of the Southern Apennines during glacial–interglacial cycles.

Early Holocene volcanic ash fallout in the Yammoûneh lacustrine basin (Lebanon): Tephrochronological implications for the Near East

A volcanic ash layer (Tyam-1) was identified in Holocene sediments from the Yammoûneh paleo-lake (Lebanon). The ash layer consisted of colourless shards. The major elemental chemistry of the glass as determined by electron microprobe analyses indicates a rhyolitic composition. Radiocarbon dating of detrital wood fragments located in the ash layer suggests an age of approximately 8.6 ka cal. BP. The timing of the layer and a chemical comparison with other published data suggest that Tyam-1 likely originated from Anatolia, and likely corresponds to early Holocene Z3–Z4–Z5 tephras. The preliminary results provided in this manuscript suggest a new stratigraphical and chronological marker for the continental records of Lebanon and neighbouring regions.

Fallout and distribution of volcanic ash over Argentina following the May 2008 explosive eruption of Chaitén, Chile

The major explosive eruption of Chaitén volcano, Chile, in May 2008 provided a rare opportunity to track the long‐range dispersal and deposition of fine volcanic ash. The eruption followed ∼10,000 years of quiescence, was the largest explosive eruption globally since Hudson, Chile, in 1991, and was the first explosive rhyolitic eruption since Novarupta, Alaska, in 1912. Field examination of distal ashfall indicates that ∼1.6 × 1011 kg of ash (dense rock equivalent volume of ∼0.07 km3) was deposited over ∼2 × 105 km2 of Argentina during the first week of eruption. The minimum eruption magnitude, estimated from the mass of the tephra deposit, is 4.2. Several discrete ashfall units are identifiable from their distribution and grain size characteristics, with more energetic phases showing a bimodal size distribution and evidence of cloud aggregation processes. Ash chemistry was uniform throughout the early stages of eruption and is consistent with magma storage prior to eruption at depths of 3–6 km. Deposition of ash over a continental region allowed the tracking of eruption development and demonstrates the potential complexity of tephra dispersal from a single eruption, which in this case comprised several phases over a week‐long period of intense activity.

Ash fallout scenarios at Vesuvius: Numerical simulations and implications for hazard assessment

Volcanic ash fallout subsequent to a possible renewal of the Vesuvius activity represents a serious threat to the highly urbanized area around the volcano. In order to assess the relative hazard we consider three different possible scenarios such as those following Plinian, Sub-Plinian, and violent Strombolian eruptions. Reference eruptions for each scenario are similar to the 79 AD (Pompeii), the 1631 AD (or 472 AD) and the 1944 AD Vesuvius events, respectively. Fallout deposits for the first two scenarios are modeled using HAZMAP, a model based on a semi-analytical solution of the 2D advection–diffusion–sedimentation equation. In contrast, fallout following a violent Strombolian event is modeled by means of FALL3D, a numerical model based on the solution of the full 3D advection–diffusion–sedimentation equation which is valid also within the atmospheric boundary layer. Inputs for models are total erupted mass, eruption column height, bulk grain-size, bulk component distribution, and a statistical set of wind profiles obtained by the NCEP/NCAR re-analysis. We computed ground load probability maps for different ash loadings. In the case of a Sub-Plinian scenario, the most representative tephra loading maps in 16 cardinal directions were also calculated. The probability maps obtained for the different scenarios are aimed to give support to the risk mitigation strategies.

Volcanic ash forecast – application to the May 2008 Chaitén eruption

Abstract. We model the transport and subsequent deposition of ash from Chaitén volcano, Chile, during the first week of May 2008. The simulation couples the Weather Research and Forecasting (WRF) meteorological model with the FALL3D dispersion model. We only use semi-quantitative volcanological inputs based on the first eruption reports. We consider two different run types based on forecasted and hindcasted meteorological conditions. The first simulation type can be regarded as a syn-eruptive operational forecast for the 2–8 May period. We predict the evolution of the ash cloud position, the concentration of ash on air, the expected deposit thickness, and the ash accumulation rates at different localities. The comparison of model results with observed cloud arrival times and satellite images shows the goodness of the combined WRF+FALL3D forecast system and points out the feasibility of combining these two models for short-term forecast of volcanic clouds and ash fallout.