Icelandic Volcano Research Articles

Atmospheric Pollution by Iceland Volcano Lava Dispersion - the Brussels Case

In April 2010 the Icelandic Eyjafjallajokull stratovolcano emitted large clouds of volcanic ashes that provoked chaotic situations for the air traffic of the Northern hemisphere. The impact of the resulting atmospheric pollution may have widespread effects on the health of the populations living in the affected regions. For this reason, the study of the airborne particles brought by the ash clouds must cover not only their concentrations expressed in μg/m3, but also their size, shape and chemical composition. Our results revealed that during the eruption days, some periods with a higher concentration of the coarse particles (between 2.5 and 10 μm) were observed. The sphericity (R1) and roughness (R2) parameters showed specific characteristics of the particles, suggesting long distance of their origin. Furthermore, an increase up to 4 times more in the At% of the elements K, Al, Ca, Na and Si, which characterize the felsic lava, was observed during the eruption period.

The effect of volcanic activity of the Eyjafjallajökul volcano on iodine concentration in precipitation in the Czech Republic

Our measurements noticed elevated iodine concentration in precipitation due to volcanic activity. The concentrations determined in two regions of the Czech Republic increased significantly during the passage of dust cloud from Icelandic volcano Eyjafjallajökul over the sampling areas. Iodine concentration in the rainwater was up to 6.68μgdm−3 during the critical period between 16 and 20 April 2010. Measured levels were up to six times higher than background values. The increased concentrations decreased to the usual values within approximately two weeks.

Operation of Gas Turbine Engines in an Environment Contaminated With Volcanic Ash

Airborne volcanic ash poses a significant threat to the safe operation of gas turbine powered aircraft. Recent volcanic activity in Iceland and other parts of the world have resulted in interruption of air traffic and in the case of the April 2010 eruption of the Eyjafjallajökull volcano in Iceland, the interruption resulted in a significant loss of revenue. Over the past 30 years there have been several events involving commercial aircraft that have suffered significant damage to the propulsion system as a result of ingesting volcanic ash during a flight event, but a relevant engine focused database to provide guidance for dealing with the problem has not been generally available until recently. In Sept. 2010 after the Iceland volcano activity, a body of data that had not been in the public domain was released and those measurements that are described in some detail herein can be helpful to the airlines, the aircraft manufacturers, the engine manufacturers, those responsible for flight operations, and hopefully to the flight crews. The intent of this paper is to describe some of the more notable aircraft/ash cloud events, the available data associated with those encounters and how those data can be used to effectively deal with this problem while maintaining safe flight operations. The paper specifically (a) illustrates the engine damage mechanisms, (b) estimates the potential operational life of a particular class of engines if the ash concentration is at a very low level, and (c) illustrates how this database is helpful in dealing with future interruptions of flight routes caused by volcanic eruptions. A section at the end of this paper provides the comments and concerns of the industry and government stakeholders regarding this general problem area.

“The Present Obfuscation”: Cowper'sTaskand the Time of Climate Change

Climate change, I argue, is a catastrophe that resists the revelation promised by apocalyptic narrative. My case study is William Cowper's poemThe Task(1785), which I situate in two climatic contexts: the year of its composition, which saw meteorological extremes caused by the eruption of an Icelandic volcano, and an era of geologic modernity, the Anthropocene, which commenced with the industrial combustion of fossil fuels in the late eighteenth century. As volcanogenic haze migrates in Cowper's descriptions from the countryside to the greenhouse and the imperial city, the poet fails to identify a meteorology with which to distinguish nature's seasonal “revolvency” from eschatological presages or from the modernization process itself—the historical “revolution” embodied by worsening urban pollution. Climate change poses a crisis, in the dual etymological senses of a decision and a turning point, because it unsettles the duration of the present, what returns and endures and so measures alteration.

Tephra stratigraphy on the North Icelandic shelf: extending tephrochronology into marine sediments off North Iceland

Tephra stratigraphical and tephrochronological studies of marine core MD99‐2275 on the North Icelandic shelf have revealed 58 new tephra horizons within the last 7050 cal. a BP, bringing the total number of identified tephra layers to 76. So far, over 100 tephra layers have been identified in the entire core spanning the last 15 000 years. The majority of the newly identified tephra layers are basaltic in composition and originate from the most active volcanic systems in Iceland, namely Grímsvötn, Veidivötn‐Bárdarbunga and Katla. A total of 40 tephra layer land–sea correlations have been made within this time period, of which 16 represent absolutely dated tephra markers. In addition, two tephra marker series are revealed in the marine sediments and in the terrestrial tephra stratigraphy, located between c. 2300–2600 and between 5700–5900 years. For the last 15 000 years, 21 tephra markers have been recognized. The marine tephra layer frequency (TLF) reveals two peaks, within the last 2000 years, and between 5000 and 7000 years ago. It shows the same general characteristics as the terrestrial TLF curve in Iceland, which indicates that marine sediments can yield important information about volcanism in Iceland. This is useful in time segments in which terrestrial records are poor or non‐existent. The study contributes to a high‐resolution tephrochronological framework on the North Icelandic shelf, with core MD99‐2275 representing a potential stratotype section in the area, and for the northern North Atlantic–Nordic Seas region, as well as being an important contribution to the Lateglacial–early Holocene volcanic history of Iceland.

Intraglacial volcanism in the Western Volcanic Zone, Iceland

The Western Volcanic Zone in Iceland (64.19° to 65.22° N) has the morphological characteristics of a distinct Mid-Atlantic ridge segment. This volcanic zone was mapped at a scale of 1:36.000, and 258 intraglacial monogenetic volcanoes from the Late Pleistocene (0.01–0.78 Ma) were identified and investigated. The zone is characterized by infrequent comparatively large volcanic eruptions and the overall volcanic activity appears to have been low throughout the Late Pleistocene. Tholeiitic basaltic rocks dominate in the Western Volcanic Zone with about 0.5 vol. % of intermediate and silicic rocks. The basalts divide into picrites, olivine tholeiites, and tholeiites. Three main eruptive phases can be distinguished in the intraglacial volcanoes: an effusive deep-water lava phase producing basal pillow lavas, an explosive shallow-water phase producing hyaloclastites and an effusive subaerial capping lava phase. Three evolutionary stages therefore charcterize these volcanoes; late dykes and irregular minor intrusions could be added as the fourth main stage. These intrusions are potential heat sources for short-lived hydrothermal systems and may play an important role in the final shaping of the volcanoes. Substantial parts of the hyaloclastites of each unit are proximal sedimentary deposits. The intraglacial volcanoes divide into two main morphological groups, ridge-shaped volcanoes, i.e., tindars (including pillow lava ridges) and subrectangular volcanoes, i.e., tuyas and hyaloclastite or pillow lava mounds. The volume of the tuyas is generally much larger than that of the tindars. The largest tuya, Eiriksjokull, is about 48 km3 and therefore the largest known monogenetic volcano in Iceland. Many of the large volcanoes, both tuyas and tindars, show a similar, systematic range in geochemistry. The most primitive compositions were erupted first and the magmas then changed to more differentiated compositions. The ridge-shaped tindars clearly erupted from volcanic fissures and the more equi-dimensional tuyas mainly from a single crater. It is suggested that the morphology and structure of the intraglacial volcanos mainly depends on two factors, (a) tectonic control and (b) availability of magma at the time of eruption.

Volcanic impacts on the Holocene vegetation history of Britain and Ireland? A review and meta-analysis of the pollen evidence

Volcanic ash layers show that the products of Icelandic volcanism reached Britain and Ireland many times during the Holocene. Historical records suggest that at least one eruption, that of Laki in a.d. 1783, was associated with impacts on vegetation. These results raise the question: did Icelandic volcanism affect the Holocene vegetation history of Britain and Ireland? Several studies have used pollen data to address this issue but no clear consensus has been reached. We re-analyse the palynological data using constrained ordination with various representations of potential volcanic impacts. We find that the palynological evidence for volcanic impacts on vegetation is weak but suggest that this is a case of absence of evidence and is not necessarily evidence of absence of impact. To increase the chances of identifying volcanic impacts, future studies need to maximise temporal resolution, replicate results, and investigate a greater number of tephras in a broader range of locations, including more studies from lake sediments.

Interpretation of Accurate UV Polarization Lidar Measurements: Application to Volcanic Ash Number Concentration Retrieval

Abstract In this paper, accurate UV polarization measurements are performed on a volcanic ash cloud after long-range transport at Lyon, France (45.76°N, 4.83°E). The volcanic particles are released from the mid-April 2010 eruption of the Eyjafjallajökull Icelandic volcano (63.63°N, 19.62°W). The aerosol UV depolarization, which arises from nonspherical volcanic ash particles, serves as an independent means to discriminate ash from nonash particles in the volcanic cloud. This discrimination is only feasible if the intrinsic ash particle depolarization ration δash is accurately determined. In this paper, the δash value [δash = (40.5 ± 2.0)%] is derived from literature laboratory measurements on a scattering matrix to ensure ash particle specificity. It is shown that traditional approaches, based on direct lidar depolarization ratio δa measurements, are only valid very close to the source region, because δa may be very different from δash, when nonash particles are present. For the first time, observed lidar depolarization ratios, in the range from a few percent to 40%, are hence interpreted in comparison with δash taken as a reference. It is then shown how to use the sensitive and accurate UV polarization measurements to access to the size-averaged number concentration vertical profile of volcanic ash particles in the troposphere. Vertical profiles of the backscattering coefficient specific to volcanic ash particles, providing altitude-resolved ash particle number concentrations, are presented in the troposphere after optical scattering computation. This new methodology can be applied to other aerosols events and for other optical remote sensing experiments.

Eyjafjallajökull volcanic ash concentrations determined using Spin Enhanced Visible and Infrared Imager measurements

Between 14 April and 25 May, 2010, Eyjafjallajökull volcano in Iceland erupted a large amount of fine grained ash. Dispersion models and satellite data were used to identify the location of the ash cloud, but accurate quantitative forecasts of the concentrations could not be made. By using multispectral satellite measurements from the Spin Enhanced Visible and Infrared Imager (SEVIRI), it is shown that quantitative estimates of the mass loadings (g m−2) can be made with a detection limit ∼0.2 g m−2, every 15 minutes. These data represent the most comprehensive coverage, in space and time, of the Eyjafjallajökull ash and its movement. A new ash concentration chart is proposed that removes the ambiguity inherent in assigning high concentrations to highly negative brightness temperature differences. Validation of satellite ash retrievals against measurements from aircraft, ground‐based lidars, and air quality data is presented. The results show a mean bias of −47 μg m−3 and standard deviation of ±154 μg m−3. The satellite ash retrievals are sufficiently accurate for use with dispersion models to constrain ash concentration forecasts. Concentrations in the dense parts of the dispersing ash cloud occasionally exceeded 4 mg m−3 (∼3% of ash‐affected pixels), and ash clouds with concentrations >2 mg m−3 covered large parts of European airspace on several occasions (∼50% of ash‐affected pixels). The statistical analysis leads naturally to a logarithmic scale for assigning ash concentration limits. We suggest that a better approach is to utilize a dosage and illustrate this using a simple model of ash deposition on jet engines.

The notorious E15 in pictures

Physics Today's Earth sciences correspondent took her camera on a field trip to the scourge of transatlantic air travelers in 2010, the Icelandic volcano Eyjafjallajokull.

Improved detection of sulphur dioxide in volcanic plumes using satellite‐based hyperspectral infrared measurements: Application to the Eyjafjallajökull 2010 eruption

The explosive phase of the eruption of the Eyjafjallajökull volcano in Iceland beginning on 14 April 2010 caused extensive disruption to aviation in Europe with serious social and economic consequences. Despite its impact, the explosive phase was modest in size and the amount of sulphur dioxide (SO2) released was low. The potential of hyperspectral thermal infrared measurements to discriminate emissions from similar events by measuring SO2 is examined using the Infrared Atmospheric Sounding Interferometer (IASI) on board MetOp‐A. The transported plume in the initial stages of the explosive phase contained low amounts of SO2 at low altitude which placed it at the detection limit of space‐based sensors used to monitor the volcanic threat to aviation using current methods. A recently developed technique for the fast retrieval of SO2 from IASI is applied in the context of the Eyjafjallajökull eruption to show that IASI is easily capable of sensing the SO2 in the plume at this stage where existing methods fail. The fast SO2 retrieval is calibrated against a fully quantitative optimal estimation retrieval of SO2 total column amount and plume altitude to derive the detection limit for the plume on 15 April 2010. An estimate of the general detection limit for the instrument is placed conservatively at 0.3 Dobson Units (DU) which is an order of magnitude lower than previously thought.

X-ray microanalysis of volcanic ash

The 2010 eruption of Eyjafjallajökull volcano in Iceland demonstrated the disruptive nature of high-level volcanic ash emissions to the world's air traffic.The chemistry of volcanic material is complex and varied. Different eruptions yield both compositional and morphological variation. Equally a single eruption, such as that in Iceland will evolve over time and may potentially produce a range of volcanic products of varying composition and morphology. This variability offers the petrologist the opportunity to derive a tracer to the origins both spatially and temporally of a single particle by means of electron microbeam analysis.EPMA of volcanic ash is now an established technique for this type of analysis as used in tephrachronology. However, airborne paniculate material may, as in the case of Eyjafjallajökull, result in a particle size that is too small and too dispersed for preparation of standard EPMA mounts. Consequently SEM-EDS techniques are preferred for this type of quantitative analysis . Results of quantitative SEM-EDS analysis yield data with a larger precision error than EPMA yet sufficient to source the original eruption. Uncoated samples analyzed using variable pressure SEM yield slightly poorer results at modest pressures.

Eyjafjallajökull ash concentrations derived from both lidar and modeling

Following the eruption of the Icelandic volcano Eyjafjallajökull on the 14 April 2010, ground‐based N2‐Raman lidar (GBL) measurements were used to trace the temporal evolution of the ash plume from 16 to 20 April 2010 above the southwestern suburb of Paris. The nighttime overpass of the Cloud‐Aerosol LIdar with Orthogonal Polarization onboard Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation satellite (CALIPSO/CALIOP) on 17 April 2010 was an opportunity to complement GBL observations. The plume shape retrieved from GBL has been used to assess the size range of the particles size. The lidar‐derived aerosol mass concentrations (PM) have been compared with model‐derived PM concentrations held in the Eulerian model Polair3D transport model, driven by a source term inferred from the SEVIRI sensor onboard Meteosat satellite. The consistency between model and ground‐based wind lidar and CALIOP observations has been checked. The spatial and temporal structures of the ash plume as estimated by each instrument and by the Polair3D simulations are in agreement. The ash plume was associated with a mean aerosol optical thickness of 0.1 ± 0.06 and 0.055 ± 0.053 for GBL (355 nm) and CALIOP (532 nm), respectively. Such values correspond to ash mass concentrations of ∼400 ± 160 and ∼720 ± 670 μg m−3, respectively, within the ash plume, which was lower than 0.5 km in width. The relative uncertainty is ∼75% and mainly due to the assessment of the specific cross‐section assuming an aerosol density of 2.6 g cm−3. The simulated ash plume is smoother leading to integrated mass of the same order of magnitude (between 50 and 250 mg m−2).

Silicic magma petrogenesis in Iceland by remelting of hydrothermally altered crust based on oxygen isotope diversity and disequilibria between zircon and magma with implications for MORB

Terra Nova, 24, 227–232, 2012AbstractPetrogenesis of silicic magmas in Iceland has fundamental significance for understanding the relative importance of fractional crystallization of mantle‐derived basalt and partial melting of hydrothermally altered basaltic crust in formation of the earliest continental crust. First results of in situ oxygen isotope investigation of zircons in large‐volume silicic eruptive products of three volcanoes in Iceland (Askja, Torfajökull, and Hekla) demonstrate isotope diversity and disequilibria and long U–Th zircon pre‐eruptive residence of 103–104 year. This suggests that zircons did not grow from their host melts but instead were inherited from older magma batches and leftover cumulates with generally low and variable δ18O values. This study demonstrates that segregation of cubic kilometres of silicic magma is faster than mineral‐diffusive or recrystallization time‐scales (estimated at ∼103 years), and it suggests that partial melting of hydrothermally altered and oxidized oceanic crust is the mechanism that best explains silicic rocks in Iceland and early earth environments.

A short-term intervention study — Impact of airport closure due to the eruption of Eyjafjallajökull on near-field air quality

The eruption of the Icelandic volcano Eyjafjallajökull in April 2010 resulted in an unprecedented flight-ban at many European airports for many days. While much of the scientific interest in the eruption was related to the chemical and physical properties of the ash cloud and how it dispersed, a secondary effect was the reduction in aviation emissions at airports around Europe and elsewhere. In this study we aim to quantify the impact the flight-ban had on concentrations of nitrogen oxides at measurement sites close to London Heathrow Airport. A technique based on boosted regression trees is used to build an explanatory model of NOx and NO2 concentrations based on hourly meteorological and aircraft emissions data in the 3-years preceding the flight-ban. We show that the airport closure resulted in an unambiguous effect on NOx and NO2 concentrations close to the airport, even though the ban only lasted six days. Furthermore, we estimate the annual impact airport emissions have on mean concentrations of NOx and NO2 for different years and compare these estimates with a detailed dispersion modelling study and previous work that was based on the analysis of monitoring site data. For the receptor most affected by the flight-ban approximately 200 m south of the airport we estimate the airport contributes about 13.5 μg m−3 NOx (≈23% of the total measured NOx concentration), which is similar in magnitude to detailed dispersion modelling estimates of 12.0 μg m−3, but approximately twice that of other estimates based on the analysis of ambient measurements. Other measurement sites showed more mixed results due to the prevailing meteorology at the time of the ban, which affected the extent to which these sites were affected by the flight-ban. The techniques developed and applied in this paper would have application to other short-term interventions that affect air quality.

Ian S. E. Carmichael (1930–2011)

Ian S. E. Carmichael, who had a highly imaginative research career and was legendary for his successful mentoring of graduate students, died in Berkeley, Calif., on 26 August 2011. Ian applied thermodynamic theory, experiment, and the ground truth of fieldwork to the study of magmatic rocks. Throughout the arc of his career, he played a critical role in transforming igneous petrology from a discipline that was largely descriptive to one that is rigorously quantitative. Ian was born in London on 29 March 1930 and was educated at Westminster School. He spent 2 years in the British Army (as a parachutist and a second lieutenant in the Corps of Royal Engineers), where he saw service in Egypt, Palestine, and Sudan. He obtained his B.A. and M.A. in geology at Cambridge University in 1954 and then traveled to Canada, where he prospected for copper and wintered in the Arctic. Ian returned to England and obtained his Ph.D. in 1958 at Imperial College London. His thesis, on Thingmuli volcano in eastern Iceland, addressed one of the most contentious issues in Earth science at the time (before the days of isotope geochemistry and plate tectonics), namely, the origin of silicic magma from basalt in the absence of preexisting continental crust. The problem went to the heart of crustal evolution.

Modeling the resuspension of ash deposited during the eruption of Eyjafjallajökull in spring 2010

Eyjafjallajökull, a volcano in southern Iceland, erupted explosively in April and May 2010 depositing ash over a region of more than 3000 km2 to the east and southeast of the volcano. This deposited ash has been frequently remobilized by the wind causing concern for the health of Icelanders living in the region. An investigation was carried out to determine whether it would be possible to produce forecasts of days when high airborne ash concentrations were likely to occur. Information about the spatially varying surface characteristics of the region of deposited ash is not available so in the modeling approach adopted here ash is released from the surface at a rate proportional to the cube of the excess friction velocity (local friction velocity minus a threshold) only when the friction velocity exceeds a threshold. Movement of the resuspended ash is then modeled in a Lagrangian dispersion model. Modeled ash concentrations are compared to observed concentrations from two periods; PM10 observations between 23 May and 2 July 2010 and airborne particle counts between 21 September 2010 and 16 February 2011. More than 66% of the resuspension episodes between May and July are captured by the model and the relative magnitudes of the modeled episodes in this period are in good agreement with the observations. 66% of episodes between October and February are also captured by the model although there is an increase in the false alarm rate which appears to be due to the influence of precipitation.

Wind erosion of volcanic materials in the Hekla area, South Iceland

Abstract Iceland has extensive areas with intense aeolian processes, in spite of humid climate. We measured wind erosion in a 110 km2 heterogeneous sandy area near the Mt. Hekla volcano in South Iceland. The area is sparsely vegetated and covered by volcanic materials. Measurements were made during two summer seasons in 2008–2009 with dust traps at 25 locations employing a ‘single dust trap method’ after characterizing sediment height profiles. Sets of electronic equipment that measured wind erosion and several weather parameters were placed at two locations. The results show a large variation in sediment transport with maximum transport in storms ranging from 0 to 1788 kg m−1 at each site and maximum average transport during storm reaching 244 kg m−1 h−1. The aeolian transport each summer ranged from 1 to 2981 kg m−1. Amount of loose sandy sediments on the surface, sediment texture and proximity to water channels are important factors explaining site differences. Wind erosion was most intense in the north-eastern part of the area, with >80% loose sand on the surface but less intense closest to the volcano where coarse pumice characterizes the surface. The research shows a pathway of sediment transport on a landscape scale with north-easterly winds, into the Thjorsa river, enhanced by landscape characteristics and seasonally active water channel. Pumice grains >8 mm in diameter were transported by saltation. Grains >1 mm were commonly >20% of materials collected at 30 cm height, which is explained by low density of the volcanic materials and high wind velocities.

On the visibility of airborne volcanic ash and mineral dust from the pilot’s perspective in flight

In April 2010, volcanic ash from the Eyjafjalla volcano in Iceland strongly impacted aviation in Europe. In order to prevent a similar scenario in the future, a threshold value for safe aviation based on actual mass concentrations was introduced (2mgm−3 in Germany). This study contrasts microphysical and optical properties of volcanic ash and mineral dust and assesses the detectability of potentially dangerous ash layers (mass concentration larger than 2mgm−3) from a pilot’s perspective during a flight. Also the possibility to distinguish between volcanic ash and other aerosols is investigated. The visual detectability of airborne volcanic ash is addressed based on idealized radiative transfer simulations and on airborne observations with the DLR Falcon gathered during the Eyjafjalla volcanic ash research flights in 2010 and during the Saharan Mineral Dust Experiments in 2006 and 2008. Mineral dust and volcanic ash aerosol both show an enhanced coarse mode (>1μm) aerosol concentration, but volcanic ash aerosol additionally contains a significant number of Aitken mode particles (<150nm) not present in mineral dust. Under daylight clear-sky conditions and depending on the viewing geometry, volcanic ash is visible already at mass concentrations far below what is currently considered dangerous for aircraft engines. However, it is not possible to visually distinguish volcanic ash from other aerosol layers or to determine whether a volcanic ash layer is potentially dangerous (mass concentration larger or smaller than 2mgm−3). Different appearances due to microphysical differences of both aerosol types are not detectable by the human eye. Nonetheless, as ash concentrations can vary significantly over distances travelled by an airplane within seconds, this visual threat evaluation may contribute greatly to the short-term response of pilots in ash-contaminated air space.

Generation of volcanic ash by basaltic volcanism

The recent eruptions of Eyjafjallajökull and Grimsvötn volcanoes in Iceland demonstrate the importance of a better understanding of processes leading to the formation of volcanic ash, specifically of fine volcanic ash that poses a threat to air traffic. Continuous deformation and brittle‐type experiments were carried out to better constrain these processes. The studies on short‐time continuous deformation behavior of basaltic melt showed viscoelastic properties deviating from hydrodynamic Newtonian models by more than 5 orders of magnitude. High‐temperature deformation experiments on basaltic rock samples revealed an increase of elastic strengths as approaching the melting regime, also pointing to a very complex behavior at the solid‐ductile boundary. Understanding magma fragmentation from the “liquid” side is a challenge, but meanwhile we propose a pragmatic solution: a thermodynamic model based on fracture mechanics. This model is in agreement with experiments and observations that show that fine volcanic ash is produced by brittle‐type fragmentation of magma. A critical material property was defined, characterizing the conditions for brittle fragmentation: the fracture surface energy density, which represents the critical fragmentation energy. Short‐term fracture experiments using silicate glass have been performed to investigate the formation of ash‐sized particles by brittle failure and to extract this critical physical property, which was found to range between 40 and 130 J/m2. This value is in good agreement to fragmentation energies determined from experiments using remelted volcanic rocks. Now there is a tool to define critical conditions for the production of volcanic ash of a specific magma type.