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Sample records for airborne volcanic ash

  1. In vitro evaluation of pulmonary deposition of airborne volcanic ash

    NASA Astrophysics Data System (ADS)

    Lähde, Anna; Sæunn Gudmundsdottir, Sigurbjörg; Joutsensaari, Jorma; Tapper, Unto; Ruusunen, Jarno; Ihalainen, Mika; Karhunen, Tommi; Torvela, Tiina; Jokiniemi, Jorma; Järvinen, Kristiina; Gíslason, Sigurður Reynir; Briem, Haraldur; Gizurarson, Sveinbjörn

    2013-05-01

    There has been an increasing interest in the effects of volcanic eruption on the environment, climate, and health following two recent volcanic eruptions in Iceland. Although health issues are mainly focused on subjects living close to the eruption due to the high concentration of airborne ash and gasses in close vicinity to the volcanoes, the ash may also reach high altitude and get distributed thousands of kilometers away from the volcano. Ash particles used in the studies were collected at the Eyjafjallajökull and Grímsvötn eruption sites. The composition, size, density and morphology of the particles were analyzed and the effect of particle properties on the re-dispersion and lung deposition were studied. The aerodynamic size and morphology of the particles were consistent with field measurement results obtained during the eruptions. Due to their size and structure, the ash particles can be re-suspended and transported into the lungs. The total surface area of submicron ash particles deposited into the alveolar and tracheobronchial regions of the lungs were 3-9% and 1-2%, respectively. Although the main fraction of the surface area is deposited in the head airways region, a significant amount of particles can deposit into the alveolar and tracheobronchial regions. The results indicate that a substantial increase in the concentration of respirable airborne ash particles and associated health hazard can take place if the deposited ash particles are re-suspended under dry, windy conditions or by outdoor human activity.

  2. On the visibility of airborne volcanic ash and mineral dust

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Sauer, D. N.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B. C.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-12-01

    airborne aerosol layer and the background, the illumination, the particle size distribution and mass concentration, the wavelength-dependent light scattering and absorption by the aerosol layer, the human perception, etc. In addition, the optical depth along the line of sight through an aerosol layer is more important than just the (vertical) optical depth, which is measured, for example, by sun photometers or satellites. The results of our study are in particular interesting for the question on the visibility of volcanic ash. Our analyses of "visible ash" demonstrate that under clear sky conditions volcanic ash is visible already at concentrations far below what is currently considered as the upper limit for safe operation of an aircraft engine (2 mg m-3). The presence of a grayish-brown layer in the atmosphere does not unambiguously indicate the presence of volcanic ash. An uninformed observer is unlikely to identify an aged volcanic ash layer in his field of view without further information. The presence of clouds would make it even more complicated to visually detect volcanic ash. In regions with high background aerosol loading in the atmosphere from natural or anthropogenic influences, such as seen in large parts of Asia, the visual detection of volcanic ash as an additional contaminant will be substantially more difficult.

  3. Airborne volcanic ash; a global threat to aviation

    USGS Publications Warehouse

    Neal, Christina A.; Guffanti, Marianne C.

    2010-01-01

    The world's busy air traffic corridors pass over or downwind of hundreds of volcanoes capable of hazardous explosive eruptions. The risk to aviation from volcanic activity is significant - in the United States alone, aircraft carry about 300,000 passengers and hundreds of millions of dollars of cargo near active volcanoes each day. Costly disruption of flight operations in Europe and North America in 2010 in the wake of a moderate-size eruption in Iceland clearly demonstrates how eruptions can have global impacts on the aviation industry. Airborne volcanic ash can be a serious hazard to aviation even hundreds of miles from an eruption. Encounters with high-concentration ash clouds can diminish visibility, damage flight control systems, and cause jet engines to fail. Encounters with low-concentration clouds of volcanic ash and aerosols can accelerate wear on engine and aircraft components, resulting in premature replacement. The U.S. Geological Survey (USGS), in cooperation with national and international partners, is playing a leading role in the international effort to reduce the risk posed to aircraft by volcanic eruptions.

  4. On the visibility of airborne volcanic ash and other aerosols from the pilot's perspective in flight

    NASA Astrophysics Data System (ADS)

    Weinzierl, B.; Sauer, D.; Minikin, A.; Reitebuch, O.; Dahlkötter, F.; Mayer, B.; Emde, C.; Tegen, I.; Gasteiger, J.; Petzold, A.; Veira, A.; Kueppers, U.; Schumann, U.

    2012-04-01

    In April 2010, the volcanic ash cloud from the Eyjafjalla volcano in Iceland strongly impacted aviation in Europe: more than 100 000 flights were cancelled affecting more than 10 million passengers. Several incidents in the past have shown that volcanic ash may have severe consequences on aviation. Therefore, one operational problem is whether a pilot has the means to avoid flying through potentially dangerous volcanic ash just by visual observation of the sky out of the cockpit of an aircraft. The goal of our study is to assess whether it is possible from the pilot's perspective in flight to detect the presence of volcanic ash and to distinguish between volcanic ash and other aerosols just by sight. In our presentation, we focus the comparison with other aerosols on aerosol types impacting aviation. Besides volcanic ash, dust storms are known to be avoided by aircraft. We approach the question on the visibility of volcanic ash and other aerosol layers in flight starting from the inspection of photographs taken during the Eyjafjalla volcanic ash research flights with the DLR Falcon in April/May 2010 and mass concentrations measured during those flights. Furthermore we use airborne data from the Saharan Mineral Dust Experiments (SAMUM) in 2006 and 2008. We complement this analysis with idealized radiative transfer simulations with libRadtran for a variety of selected viewing geometries. Both aerosol types, Saharan mineral dust and volcanic ash, show an enhanced coarse mode (> 1 µm) aerosol concentration, but volcanic ash aerosol additionally contains a significant number of Aitken mode particles (< 150 nm), which are not present in mineral dust. Volcanic ash is slightly more absorbing than mineral dust, and the spectral behaviour of the refractive index is slightly different. According to our simulations, these differences are not detectable just by human eye. The consequences of our study for aircraft operation are the following: under clear sky conditions

  5. Analyses of in-situ airborne volcanic ash from the February 2000 eruption of Hekla Volcano, Iceland

    NASA Astrophysics Data System (ADS)

    Pieri, D.; Ma, C.; Simpson, J. J.; Hufford, G.; Grindle, T.; Grove, C.

    2002-08-01

    A McDonnell-Douglas DC-8 NASA research aircraft inadvertently flew into an airborne volcanic ash plume from the 26 February 2000 eruption of Hekla Volcano. Filter samples from the aircraft were compared with ``normal use'' and ``pristine clean'' filters using SEM, energy-dispersive x-ray spectrometer, and Nicolet FTIR spectrophotometer analyses. These analyses confirm that the DC-8 encountered airborne volcanic ash from Hekla Volcano. This result is supported by independent onboard heated aerosol observations at the time of the encounter. The analyses further demonstrate the ambiguous nature of the dual band thermal IR (``split window'') method for detecting volcanic ash from the point of view of aviation safety. They also highlight the utility of in situ aircraft filter-based observations of volcanic aerosols for scientific purposes.

  6. Identification and characterization of individual airborne volcanic ash particles by Raman microspectroscopy.

    PubMed

    Ivleva, Natalia P; Huckele, Susanne; Weinzierl, Bernadett; Niessner, Reinhard; Haisch, Christoph; Baumann, Thomas

    2013-11-01

    We present for the first time the Raman microspectroscopic identification and characterization of individual airborne volcanic ash (VA) particles. The particles were collected in April/May 2010 during research aircraft flights, which were performed by Deutsches Zentrum für Luft- und Raumfahrt in the airspace near the Eyjafjallajökull volcano eruption and over Europe (between Iceland and Southern Germany). In addition, aerosol particles were sampled by an Electrical Low Pressure Impactor in Munich, Germany. As references for the Raman analysis, we used the spectra of VA collected at the ground near the place of eruption, of mineral basaltic rock, and of different minerals from a database. We found significant differences in the spectra of VA and other aerosol particles (e.g., soot, nitrates, sulfates, and clay minerals), which allowed us to identify VA among other atmospheric particulate matter. Furthermore, while the airborne VA shows a characteristic Raman pattern (with broad band from ca. 200 to ca. 700 cm(-1) typical for SiO₂ glasses and additional bands of ferric minerals), the differences between the spectra of aged and fresh particles were observed, suggesting differences in their chemical composition and/or structure. We also analyzed similarities between Eyjafjallajökull VA particles collected at different sampling sites and compared the particles with a large variety of glassy and crystalline minerals. This was done by applying cluster analysis, in order to get information on the composition and structure of volcanic ash. PMID:24121468

  7. Modeling volcanic ash dispersal

    ScienceCinema

    None

    2016-07-12

    Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

  8. Modeling volcanic ash dispersal

    SciTech Connect

    2010-10-22

    Explosive volcanic eruptions inject into the atmosphere large amounts of volcanic material (ash, blocks and lapilli). Blocks and larger lapilli follow ballistic and non-ballistic trajectories and fall rapidly close to the volcano. In contrast, very fine ashes can remain entrapped in the atmosphere for months to years, and may affect the global climate in the case of large eruptions. Particles having sizes between these two end-members remain airborne from hours to days and can cover wide areas downwind. Such volcanic fallout entails a serious threat to aircraft safety and can create many undesirable effects to the communities located around the volcano. The assessment of volcanic fallout hazard is an important scientific, economic, and political issue, especially in densely populated areas. From a scientific point of view, considerable progress has been made during the last two decades through the use of increasingly powerful computational models and capabilities. Nowadays, models are used to quantify hazard scenarios and/or to give short-term forecasts during emergency situations. This talk will be focused on the main aspects related to modeling volcanic ash dispersal and fallout with application to the well known problem created by the Eyjafjöll volcano in Iceland. Moreover, a short description of the main volcanic monitoring techniques is presented.

  9. Airborne lidar observations of volcanic ash during the eruption of Eyjafjallajökull in Spring 2010

    NASA Astrophysics Data System (ADS)

    Marenco, F.; Johnson, B.; Turnbull, K.; Haywood, J.; Newman, S.; Webster, H.; Cooke, M.; Dorsey, J.; Ricketts, H.; Clarisse, L.

    2012-04-01

    The London Volcanic Ash Advisory Centre (VAAC), based at the Met Office, provided forecast guidance for the Civil Aviation Authority during the eruption of Eyjafjallajökull in April-May 2010. Besides providing daily forecasts using the Numerical Atmospheric-dispersion Modelling Environment (NAME), a series of observational activities were carried out by the Met Office, involving ground-based lidars, the exploitation of satellite data, and research flights using the Facility for Airborne Atmospheric Measurements BAe-146 research aircraft (FAAM, www.faam.ac.uk), on which this talk is focused. Due to safety restrictions, aircraft sampling has only been performed in areas where ash concentrations where forecasted to be less than 2000 μg/m3. Volcanic ash layers were observed using an elastic backscatter lidar on-board the FAAM aircraft operating at 355 nm, which allowed detailed mapping of the plumes. A flight on 4 May overpassed the ground-based lidar in Aberystwyth a few times. This provided ground truth validation of the on-board lidar and of its data inversion procedure. The ash layer during this flight was found to be in patches of short horizontal extent, but despite the strong horizontal inhomogeneity the two lidars showed excellent qualitative and quantitative agreement. Moreover, radiative transfer computations using the lidar-derived profiles of aerosol extinction led to a good reconstruction of observed radiance spectra with on-board spectrometers. Aircraft in situ measurements of the particle size-distribution permitted the evaluation of a coarse extinction fraction (ranging 0.5-1) and a coarse mode specific extinction (0.6-0.9 m2/g) for six research flights. These quantities were then used to convert the lidar-derived aerosol extinction to ash concentration (with an estimated uncertainty of a factor of two). The combination of lidar and in-situ sampling of aerosol properties has thus offered us the opportunity to compile a dataset of the airborne

  10. Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

    NASA Astrophysics Data System (ADS)

    Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

    2013-12-01

    Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to

  11. Volcanic Ash Transport and Dispersion Forecasting

    NASA Astrophysics Data System (ADS)

    Servranckx, R.; Stunder, B.

    2006-12-01

    Volcanic ash transport and dispersion models (VATDM) have been used operationally since the mid 1990's by the International Civil Aviation Organization (ICAO) designated Volcanic Ash Advisory Centers (VAAC) to provide ash forecast guidance. Over the years, significant improvements in the detection and prediction of airborne volcanic ash have been realized thanks to improved models, increases in computing power, 24-hr real time monitoring by VAACs / Meteorological Watch Offices and close coordination with Volcano Observatories around the world. Yet, predicting accurately the spatial and temporal structures of airborne volcanic ash and the deposition at the earth's surface remains a difficult and challenging problem. The forecasting problem is influenced by 3 main components. The first one (ERUPTION SOURCE PARAMETERS) comprises all non-meteorological parameters that characterize a specific eruption or volcanic ash cloud. For example, the volume / mass of ash released in the atmosphere, the duration of the eruption, the altitude and distribution of the ash cloud, the particle size distribution, etc. The second component (METEOROLOGY) includes all meteorological parameters (wind, moisture, stability, etc.) that are calculated by Numerical Weather Prediction models and that serve as input to the VATDM. The third component (TRANSPORT AND DISPERSION) combines input from the other 2 components through the use of VATDM to transport and disperse airborne volcanic ash in the atmosphere as well as depositing it at the surface though various removal mechanisms. Any weakness in one of the components may adversely affect the accuracy of the forecast. In a real-time, operational response context such as exists at the VAACs, the rapid delivery of the modeling results puts some constraints on model resolution and computing time. Efforts are ongoing to evaluate the reliability of VATDM forecasts though the use of various methods, including ensemble techniques. Remote sensing data

  12. Volcanic ash impacts on critical infrastructure

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    supply managers include: monitoring turbidity levels in raw water intakes, and if necessary increasing chlorination to compensate for higher turbidity; managing water demand; and communicating monitoring results with the public to allay fears of contamination. Ash can cause major damage to wastewater disposal systems. Ash deposited onto impervious surfaces such as roads and car parks is very easily washed into storm drains, where it can form intractable masses and lead to long-term flooding problems. It can also enter wastewater treatment plants (WWTPs), both through sewer lines and by direct fallout. Damage to modern WWTPs can run into millions of dollars. Ash falls reduce visibility creating hazards for ground transportation. Dry ash is also readily remobilised by vehicle traffic and wind, and dry and wet ash deposits will reduce traction on paved surfaces, including airport runways. Ash cleanup from road and airports is commonly necessary, but the large volumes make it logistically challenging. Vehicles are vulnerable to ash; it will clog filters and brake systems and abrade moving parts within engines. Lastly, modern telecommunications networks appear to be relatively resilient to volcanic ash fall. Signal attenuation and interference during ash falls has not been reported in eruptions over the past 20 years, with the exception of interference from ash plume-generated lightning. However, some telecommunications equipment is vulnerable to airborne ash, in particular heating, ventilation and air-conditioning (HVAC) systems which may become blocked from ash ingestion leading to overheating. This summary of volcanic ash impacts on critical infrastructure provides insight into the relative vulnerability of infrastructure under a range of different ashfall scenarios. Identifying and quantifying these impacts is an essential step in building resilience within these critical systems. We have attempted to consider interdependencies between sectors in a holistic way using

  13. Volcanic ash impacts on critical infrastructure

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas M.; Stewart, Carol; Sword-Daniels, Victoria; Leonard, Graham S.; Johnston, David M.; Cole, Jim W.; Wardman, Johnny; Wilson, Grant; Barnard, Scott T.

    2012-01-01

    supply managers include: monitoring turbidity levels in raw water intakes, and if necessary increasing chlorination to compensate for higher turbidity; managing water demand; and communicating monitoring results with the public to allay fears of contamination. Ash can cause major damage to wastewater disposal systems. Ash deposited onto impervious surfaces such as roads and car parks is very easily washed into storm drains, where it can form intractable masses and lead to long-term flooding problems. It can also enter wastewater treatment plants (WWTPs), both through sewer lines and by direct fallout. Damage to modern WWTPs can run into millions of dollars. Ash falls reduce visibility creating hazards for ground transportation. Dry ash is also readily remobilised by vehicle traffic and wind, and dry and wet ash deposits will reduce traction on paved surfaces, including airport runways. Ash cleanup from road and airports is commonly necessary, but the large volumes make it logistically challenging. Vehicles are vulnerable to ash; it will clog filters and brake systems and abrade moving parts within engines. Lastly, modern telecommunications networks appear to be relatively resilient to volcanic ash fall. Signal attenuation and interference during ash falls has not been reported in eruptions over the past 20 years, with the exception of interference from ash plume-generated lightning. However, some telecommunications equipment is vulnerable to airborne ash, in particular heating, ventilation and air-conditioning (HVAC) systems which may become blocked from ash ingestion leading to overheating. This summary of volcanic ash impacts on critical infrastructure provides insight into the relative vulnerability of infrastructure under a range of different ashfall scenarios. Identifying and quantifying these impacts is an essential step in building resilience within these critical systems. We have attempted to consider interdependencies between sectors in a holistic way using

  14. Volcanic ash - Terrestrial versus extraterrestrial

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1976-01-01

    A principal difference between terrestrial and extraterrestrial lavas may consist in the greater ability of terrestrial lavas to form thin films (like those of soap bubbles) and hence foams. It would follow that, in place of the pumice and spiny shards found in terrestrial volcanic ash, an extraterrestrial ash should contain minute spherules. This hypothesis may help to explain lunar microspherules.

  15. National volcanic ash operations plan for aviation

    USGS Publications Warehouse

    ,; ,

    2007-01-01

    The National Aviation Weather Program Strategic Plan (1997) and the National Aviation Weather Initiatives (1999) both identified volcanic ash as a high-priority informational need to aviation services. The risk to aviation from airborne volcanic ash is known and includes degraded engine performance (including flameout), loss of visibility, failure of critical navigational and operational instruments, and, in the worse case, loss of life. The immediate costs for aircraft encountering a dense plume are potentially major—damages up to $80 million have occurred to a single aircraft. Aircraft encountering less dense volcanic ash clouds can incur longer-term costs due to increased maintenance of engines and external surfaces. The overall goal, as stated in the Initiatives, is to eliminate encounters with ash that could degrade the in-flight safety of aircrews and passengers and cause damage to the aircraft. This goal can be accomplished by improving the ability to detect, track, and forecast hazardous ash clouds and to provide adequate warnings to the aviation community on the present and future location of the cloud. To reach this goal, the National Aviation Weather Program established three objectives: (1) prevention of accidental encounters with hazardous clouds; (2) reduction of air traffic delays, diversions, or evasive actions when hazardous clouds are present; and (3) the development of a single, worldwide standard for exchange of information on airborne hazardous materials. To that end, over the last several years, based on numerous documents (including an OFCMsponsored comprehensive study on aviation training and an update of Aviation Weather Programs/Projects), user forums, and two International Conferences on Volcanic Ash and Aviation Safety (1992 and 2004), the Working Group for Volcanic Ash (WG/VA), under the OFCM-sponsored Committee for Aviation Services and Research, developed the National Volcanic Ash Operations Plan for Aviation and Support of the

  16. An atlas of volcanic ash

    NASA Technical Reports Server (NTRS)

    Heiken, G.

    1974-01-01

    Volcanic ash samples collected from a variety of recent eruptions were studied, using petrography, chemical analyses, and scanning electron microscopy to characterize each ash type and to relate ash morphology to magma composition and eruption type. The ashes are best placed into two broad genetic categories: magnetic and hydrovolcanic (phreatomagmatic). Ashes from magmatic eruptions are formed when expanding gases in the magma form a froth that loses its coherence as it approaches the ground surface. During hydrovolcanic eruptions, the magma is chilled on contact with ground or surface waters, resulting in violent steam eruptions. Within these two genetic categories, ashes from different magma types can be characterized. The pigeon hole classification used here is for convenience; there are eruptions which are driven by both phreatic and magmatic gases.

  17. A review of volcanic ash aggregation

    NASA Astrophysics Data System (ADS)

    Brown, R. J.; Bonadonna, C.; Durant, A. J.

    2012-01-01

    Most volcanic ash particles with diameters <63 μm settle from eruption clouds as particle aggregates that cumulatively have larger sizes, lower densities, and higher terminal fall velocities than individual constituent particles. Particle aggregation reduces the atmospheric residence time of fine ash, which results in a proportional increase in fine ash fallout within 10-100 s km from the volcano and a reduction in airborne fine ash mass concentrations 1000 s km from the volcano. Aggregate characteristics vary with distance from the volcano: proximal aggregates are typically larger (up to cm size) with concentric structures, while distal aggregates are typically smaller (sub-millimetre size). Particles comprising ash aggregates are bound through hydro-bonds (liquid and ice water) and electrostatic forces, and the rate of particle aggregation correlates with cloud liquid water availability. Eruption source parameters (including initial particle size distribution, erupted mass, eruption column height, cloud water content and temperature) and the eruption plume temperature lapse rate, coupled with the environmental parameters, determines the type and spatiotemporal distribution of aggregates. Field studies, lab experiments and modelling investigations have already provided important insights on the process of particle aggregation. However, new integrated observations that combine remote sensing studies of ash clouds with field measurement and sampling, and lab experiments are required to fill current gaps in knowledge surrounding the theory of ash aggregate formation.

  18. Viscous sintering of volcanic ash

    NASA Astrophysics Data System (ADS)

    Wadsworth, F. B.; Scheu, B.; Vasseur, J.; Tuffen, H.; von Aulock, F. W.; Lavallée, Y.; Hess, K. U.; Dingwell, D. B.

    2014-12-01

    Volcanic ash is often deposited in a hot state. Volcanic ash containing glass, deposited above the glass transition interval, has the potential to sinter viscously both to itself (particle-particle) and to exposed surfaces. Here, we constrain the kinetics of this process experimentally under isothermal and non-isothermal conditions using standard glasses and volcanic ash. In the absence of external load, this process is dominantly driven by surface relaxation. In such cases the sintering process is rate-limited by the melt viscosity, the size of the particles and the melt-vapour interfacial tension. We propose a polydisperse continuum model that describes the transition from a packing of particles to a dense pore-free melt and evaluate its efficacy in describing the kinetics of volcanic viscous sintering. We apply our model to viscous sintering scenarios for cooling crystal-poor rhyolitic ash using the 2008 eruption of Chaitén volcano as a case example. We predict that moderate cooling rates result in the common observation of incomplete sintering and the preservation of pore networks. Finally we discuss the effect of crystallisation, external loading and volatile degassing or regassing during viscous sintering and assert that such complexities must be considered in the volcanic scenario.

  19. Remote sensing's contribution to life cycle analysis of volcanic ash

    NASA Astrophysics Data System (ADS)

    Watson, Matthew

    2016-04-01

    Remote sensing has been used as a tool to monitor and quantify airborne volcanic ash for several decades. As algorithms and sensors (both ground- and satellite-based) increase in sensitivity and complexity we can learn more about fragmentation, transport, deposition and remobilisation processes using these types of observations. Recent eruptions in Iceland have brought together a wealth of different data on ash processes using, a combination of remote and direct sampling and dispersion modelling. I will present the current state of knowledge on remote sensing of volcanic ash, include recent advances in detection and quantification of particle size information and discuss where the field is heading in the next five years.

  20. Optical properties of volcanic ash: improving remote sensing observations.

    NASA Astrophysics Data System (ADS)

    Whelley, Patrick; Colarco, Peter; Aquila, Valentina; Krotkov, Nickolay; Bleacher, Jake; Garry, Brent; Young, Kelsey; Rocha Lima, Adriana; Martins, Vanderlei; Carn, Simon

    2016-04-01

    Many times each year explosive volcanic eruptions loft ash into the atmosphere. Global travel and trade rely on aircraft vulnerable to encounters with airborne ash. Volcanic ash advisory centers (VAACs) rely on dispersion forecasts and satellite data to issue timely warnings. To improve ash forecasts model developers and satellite data providers need realistic information about volcanic ash microphysical and optical properties. In anticipation of future large eruptions we can study smaller events to improve our remote sensing and modeling skills so when the next Pinatubo 1991 or larger eruption occurs, ash can confidently be tracked in a quantitative way. At distances >100km from their sources, drifting ash plumes, often above meteorological clouds, are not easily detected from conventional remote sensing platforms, save deriving their quantitative characteristics, such as mass density. Quantitative interpretation of these observations depends on a priori knowledge of the spectral optical properties of the ash in UV (>0.3μm) and TIR wavelengths (>10μm). Incorrect assumptions about the optical properties result in large errors in inferred column mass loading and size distribution, which misguide operational ash forecasts. Similarly, simulating ash properties in global climate models also requires some knowledge of optical properties to improve aerosol speciation.

  1. Volcanic Ash on Slopes of Karymsky

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A volcanic eruption can produce gases, lava, bombs of rock, volcanic ash, or any combination of these elements. Of the volcanic products that linger on the land, most of us think of hardened lava flows, but volcanic ash can also persist on the landscape. One example of that persistence appeared on Siberia's Kamchatka Peninsula in spring 2007. On March 25, 2007, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the area around the Karymsky Volcano. In this image, volcanic ash from earlier eruptions has settled onto the snowy landscape, leaving dark gray swaths. The ash stains are confined to the south of the volcano's summit, one large stain fanning out toward the southwest, and another toward the east. At first glance, the ash stain toward the east appears to form a semicircle north of the volcano and sweep back east. Only part of this dark shape, however, is actually volcanic ash. Near the coast, the darker color may result from thicker vegetation. Similar darker coloring appears to the south. Volcanic ash is not really ash at all, but tiny, jagged bits of rock and glass. These jagged particles pose serious health risks to humans and animals who might inhale them. Likewise, the ash poses hazards to animals eating plants that have been coated with ash. Because wind can carry volcanic ash thousands of kilometers, it poses a more far-reaching hazard than other volcanic ejecta. Substantial amounts of ash can even affect climate by blocking sunlight. Karymsky is a stratovolcano composed of alternating layers of solidified ash, hardened lava, and volcanic rocks. It is one of many active volcanoes on Russia's Kamchatka Peninsula, which is part of the 'Ring of Fire' around the Pacific Rim. NASA image created by Jesse Allen, using data provided courtesy of the NASA/GSFC/MITI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

  2. Volcanic ash - danger to aircraft in the north Pacific

    USGS Publications Warehouse

    Neal, Christina A.; Casadevall, Thomas J.; Miller, Thomas P.; Hendley, James W.; Stauffer, Peter H.

    1997-01-01

    The world's busy air traffic corridors pass over hundreds of volcanoes capable of sudden, explosive eruptions. In the United States alone, aircraft carry many thousands of passengers and millions of dollars of cargo over volcanoes each day. Volcanic ash can be a serious hazard to aviation even thousands of miles from an eruption. Airborne ash can diminish visibility, damage flight control systems, and cause jet engines to fail. USGS and other scientists with the Alaska Volcano Observatory are playing a leading role in the international effort to reduce the risk posed to aircraft by volcanic eruptions.

  3. Airborne in-situ investigations of the Eyjafjallajökull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters

    NASA Astrophysics Data System (ADS)

    Weber, K.; Eliasson, J.; Vogel, A.; Fischer, C.; Pohl, T.; van Haren, G.; Meier, M.; Grobéty, B.; Dahmann, D.

    2012-03-01

    During the time period of the eruption of the Icelandic volcano Eyjafjallajökull in April/May 2010 the Duesseldorf University of Applied Sciences has performed 14 research flights in situations with and without the volcanic ash plume over Germany. In parallel to the research flights in Germany three measurement flights have been performed by the University of Iceland in May 2010 over the western part of Iceland. During two of these flights the outskirts of the eruption plume were entered directly, delivering most direct measurements within the eruption plume during this eruptive event. For all the measurement flights reported here, light durable piston-motor driven aircrafts were used, which were equipped with optical particle counters for in-situ measurements. Real-time monitoring of the particle concentrations was possible during the flights. As different types of optical particle counters have been used in Iceland and Germany, the optical particle counters have been re-calibrated after the flights to the same standard using gravimetric reference methods and original Eyjafjallajökull volcanic ash samples. In-situ measurement results with high spatial resolution, directly from the eruption plume in Iceland as well as from the dispersed and several days old plume over Germany, are therefore presented here for the first time. They are normalized to the same ash concentration calibration standard. Moreover, airborne particles could be sampled directly out of the eruption plume in Iceland as well as during the flights over Germany. During the research flights over Iceland from 9 May 2011 to 11 May 2011 the ash emitted from the vent of the volcano turned out to be concentrated in a narrow well-defined plume of about 10 km width at a distance of 45-60 km away from the vent. Outside this plume the airborne ash concentrations could be proved to be below 50 μg m -3 over western Iceland. However, by entering the outskirts of the plume directly the research aircraft could

  4. Volcanic ash melting under conditions relevant to ash turbine interactions.

    PubMed

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B

    2016-03-02

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines.

  5. Volcanic ash melting under conditions relevant to ash turbine interactions

    NASA Astrophysics Data System (ADS)

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B.

    2016-03-01

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines.

  6. Volcanic ash melting under conditions relevant to ash turbine interactions.

    PubMed

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B

    2016-01-01

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200-2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines. PMID:26931824

  7. Volcanic ash melting under conditions relevant to ash turbine interactions

    PubMed Central

    Song, Wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado; Dingwell, Donald B.

    2016-01-01

    The ingestion of volcanic ash by jet engines is widely recognized as a potentially fatal hazard for aircraft operation. The high temperatures (1,200–2,000 °C) typical of jet engines exacerbate the impact of ash by provoking its melting and sticking to turbine parts. Estimation of this potential hazard is complicated by the fact that chemical composition, which affects the temperature at which volcanic ash becomes liquid, can vary widely amongst volcanoes. Here, based on experiments, we parameterize ash behaviour and develop a model to predict melting and sticking conditions for its global compositional range. The results of our experiments confirm that the common use of sand or dust proxy is wholly inadequate for the prediction of the behaviour of volcanic ash, leading to overestimates of sticking temperature and thus severe underestimates of the thermal hazard. Our model can be used to assess the deposition probability of volcanic ash in jet engines. PMID:26931824

  8. Optical Properties of Volcanic Ash: Improving Remote Sensing Observations

    NASA Astrophysics Data System (ADS)

    Whelley, P.; Colarco, P. R.; Aquila, V.; Krotkov, N. A.; Bleacher, J. E.; Garry, W. B.; Young, K. E.; Lima, A. R.; Martins, J. V.; Carn, S. A.

    2015-12-01

    Many times each year explosive volcanic eruptions loft ash into the atmosphere. Global travel and trade rely on aircraft vulnerable to encounters with airborne ash. Volcanic ash advisory centers (VAACs) rely on dispersion forecasts and satellite data to issue timely warnings. To improve ash forecasts model developers and satellite data providers need realistic information about volcanic ash microphysical and optical properties. In anticipation of future large eruptions we can study smaller events to improve our remote sensing and modeling skills so when the next Pinatubo 1991 or larger eruption occurs, ash can confidently be tracked in a quantitative way. At distances >100km from their sources, drifting ash plumes, often above meteorological clouds, are not easily detected from conventional remote sensing platforms, save deriving their quantitative characteristics, such as mass density. Quantitative interpretation of these observations depends on a priori knowledge of the spectral optical properties of the ash in UV (>0.3μm) and TIR wavelengths (>10μm). Incorrect assumptions about the optical properties result in large errors in inferred column mass loading and size distribution, which misguide operational ash forecasts. Similarly, simulating ash properties in global climate models also requires some knowledge of optical properties to improve aerosol speciation. Recent research has identified a wide range in volcanic ash optical properties among samples collected from the ground after different eruptions. The database of samples investigated remains relatively small, and measurements of optical properties at the relevant particle sizes and spectral channels are far from complete. Generalizing optical properties remains elusive, as does establishing relationships between ash composition and optical properties, which are essential for satellite retrievals. We are building a library of volcanic ash optical and microphysical properties. In this presentation we show

  9. Toward an integrated Volcanic Ash Observing System in Europe

    NASA Astrophysics Data System (ADS)

    Lee, Deborah; Lisk, Ian

    2014-05-01

    Volcanic ash from the Icelandic eruption of Eyjafjallajökull in April and May of 2010 resulted in the decision by many northern European countries to impose significant restrictions on the use of their airspace. The eruption, extent and persistence of the ash revealed how reliant society now is on a safe and efficient air transport system and the fragility of that system when affected by the impact of complex natural hazards. As part of an EC framework programme, the 2011-2013 WEZARD (WEather HaZARD for aeronautics) consortium conducted a cross-industry volcanic ash capability and gap analyses, with the EUMETNET (network of 29 National Meteorological Services) led Work Package 3 focussing on a review of observational and monitoring capabilities, atmospheric dispersion modelling and data exchange. The review has revealed a patchwork of independent observing capabilities for volcanic ash, with some countries investing and others not at all, and most existing networks focus on space-based products. Existing capabilities do not provide the necessary detail on the geographical and vertical extent of volcanic ash and associated levels of contamination, which decision makers in the aviation industry require in order to decide where it is safe to fly. A resultant high priority was identified by WEZARD Work Package 3 for an enhanced observational network of complementary monitoring systems needed to initialise, validate and verify volcanic ash dispersion model output and forecasts. Thus a key recommendation is to invest in a major pre-operational demonstrator "European volcanic ash observing network", focussing on distal monitoring, and aiming to a) fill R&D gaps identified in instrumentation and algorithms and b) integrate data, where possible in near-real-time, from a range of ground-based, airborne and space-based techniques. Here we present a key WEZARD recommendation toward an integrated volcanic ash observing system in Europe, in context with other related projects

  10. Probabilistic detection of volcanic ash using a Bayesian approach

    PubMed Central

    Mackie, Shona; Watson, Matthew

    2014-01-01

    Airborne volcanic ash can pose a hazard to aviation, agriculture, and both human and animal health. It is therefore important that ash clouds are monitored both day and night, even when they travel far from their source. Infrared satellite data provide perhaps the only means of doing this, and since the hugely expensive ash crisis that followed the 2010 Eyjafjalljökull eruption, much research has been carried out into techniques for discriminating ash in such data and for deriving key properties. Such techniques are generally specific to data from particular sensors, and most approaches result in a binary classification of pixels into “ash” and “ash free” classes with no indication of the classification certainty for individual pixels. Furthermore, almost all operational methods rely on expert-set thresholds to determine what constitutes “ash” and can therefore be criticized for being subjective and dependent on expertise that may not remain with an institution. Very few existing methods exploit available contemporaneous atmospheric data to inform the detection, despite the sensitivity of most techniques to atmospheric parameters. The Bayesian method proposed here does exploit such data and gives a probabilistic, physically based classification. We provide an example of the method's implementation for a scene containing both land and sea observations, and a large area of desert dust (often misidentified as ash by other methods). The technique has already been successfully applied to other detection problems in remote sensing, and this work shows that it will be a useful and effective tool for ash detection. Key Points Presentation of a probabilistic volcanic ash detection scheme Method for calculation of probability density function for ash observations Demonstration of a remote sensing technique for monitoring volcanic ash hazards PMID:25844278

  11. Electrification of Ash in Icelandic Volcanic Plumes

    NASA Astrophysics Data System (ADS)

    Nicoll, K.; Aplin, K. L.; Houghton, I.

    2014-12-01

    Volcanic ash is known to charge electrically, producing some of the most spectacular displays of lightning on the planet. Lightning activity within volcanic plumes can be sensed remotely using systems such as the United Kingdom Met Office long-range lightning detection network, ATDnet, which recorded over 16 000 lightning strokes during the 2011 Grimsvötn eruption in Iceland. These remote sensing techniques can only be fully exploited if the charging mechanisms in volcanic plumes are well understood. Although the exact details of ash charging processes will vary from one eruption to another, triboelectrification, fractoemission, and the ''dirty thunderstorm'' mechanism are all thought to play a role in the electrification of ash near the vent. In addition to near-vent charging, observations show that charging can also occur in volcanic plumes up to hundreds of kilometres from the source region. The sustained nature of this charge in the presence of electrically conducting air suggests that a self-charging mechanism through the action of ash-to-ash contact charging (triboelectrification), may also play a role in the electrification of volcanic ash. This work describes a laboratory investigation into triboelectric charging of ash from the 2010 and 2011 volcanic eruptions of Eyjafjallajökull and Grímsvötn in Iceland respectively. Consistently with previous work, we find that the particle size distribution plays an important role in the magnitude of charging generated, specifically in terms of the normalized span of the particle size distribution. As well as triboelectrificiation, natural radioactivity in some volcanic ash could also contribute to self-charging of volcanic plumes, which is also examined here.

  12. Probabilistic detection of volcanic ash using a Bayesian approach

    NASA Astrophysics Data System (ADS)

    Mackie, Shona; Watson, Matthew

    2014-03-01

    Airborne volcanic ash can pose a hazard to aviation, agriculture, and both human and animal health. It is therefore important that ash clouds are monitored both day and night, even when they travel far from their source. Infrared satellite data provide perhaps the only means of doing this, and since the hugely expensive ash crisis that followed the 2010 Eyjafjalljökull eruption, much research has been carried out into techniques for discriminating ash in such data and for deriving key properties. Such techniques are generally specific to data from particular sensors, and most approaches result in a binary classification of pixels into "ash" and "ash free" classes with no indication of the classification certainty for individual pixels. Furthermore, almost all operational methods rely on expert-set thresholds to determine what constitutes "ash" and can therefore be criticized for being subjective and dependent on expertise that may not remain with an institution. Very few existing methods exploit available contemporaneous atmospheric data to inform the detection, despite the sensitivity of most techniques to atmospheric parameters. The Bayesian method proposed here does exploit such data and gives a probabilistic, physically based classification. We provide an example of the method's implementation for a scene containing both land and sea observations, and a large area of desert dust (often misidentified as ash by other methods). The technique has already been successfully applied to other detection problems in remote sensing, and this work shows that it will be a useful and effective tool for ash detection.

  13. Marine mesocosm bacterial colonisation of volcanic ash

    NASA Astrophysics Data System (ADS)

    Witt, Verena; Cimarelli, Corrado; Ayris, Paul; Kueppers, Ulrich; Erpenbeck, Dirk; Dingwell, Donald; Woerheide, Gert

    2015-04-01

    Volcanic eruptions regularly eject large quantities of ash particles into the atmosphere, which can be deposited via fallout into oceanic environments. Such fallout has the potential to alter pH, light and nutrient availability at local scales. Shallow-water coral reef ecosystems - "rainforests of the sea" - are highly sensitive to disturbances, such as ocean acidification, sedimentation and eutrophication. Therefore, wind-delivered volcanic ash may lead to burial and mortality of such reefs. Coral reef ecosystem resilience may depend on pioneer bacterial colonisation of the ash layer, supporting subsequent establishment of the micro- and ultimately the macro-community. However, which bacteria are involved in pioneer colonisation remain unknown. We hypothesize that physico-chemical properties (i.e., morphology, mineralogy) of the ash may dictate bacterial colonisation. The effect of substrate properties on bacterial colonisation was tested by exposing five substrates: i) quartz sand ii) crystalline ash (Sakurajima, Japan) iii) volcanic glass iv) carbonate reef sand and v) calcite sand of similar grain size, in controlled marine coral reef aquaria under low light conditions for six months. Bacterial communities were screened every month by Automated Ribosomal Intergenic Spacer Analysis of the 16S-23S rRNA Internal Transcribed Spacer region. Multivariate statistics revealed discrete groupings of bacterial communities on substrates of volcanic origin (ash and glass) and reef origin (three sands). Analysis of Similarity supported significantly different communities associated with all substrates (p=0.0001), only quartz did not differ from both carbonate and calcite sands. The ash substrate exhibited the most diverse bacterial community with the most substrate-specific bacterial operational taxonomic units. Our findings suggest that bacterial diversity and community composition during colonisation of volcanic ash in a coral reef-like environment is controlled by the

  14. Hail formation triggers rapid ash aggregation in volcanic plumes

    USGS Publications Warehouse

    Van Eaton, Alexa R.; Mastin, Larry G.; Herzog, M.; Schwaiger, Hans F.; Schneider, David J.; Wallace, Kristi; Clarke, Amanda B

    2015-01-01

    During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-characterized ‘wet’ eruption. The 2009 eruption of Redoubt Volcano in Alaska incorporated water from the surface (in this case, a glacier), which is a common occurrence during explosive volcanism worldwide. Observations from C-band weather radar, fall deposits, and numerical modeling demonstrate that volcanic hail formed rapidly in the eruption plume, leading to mixed-phase aggregation of ~95% of the fine ash and stripping much of the cloud out of the atmosphere within 30 minutes. Based on these findings, we propose a mechanism of hail-like aggregation that contributes to the anomalously rapid fallout of fine ash and the occurrence of concentrically-layered aggregates in volcanic deposits.

  15. Hail formation triggers rapid ash aggregation in volcanic plumes.

    PubMed

    Van Eaton, Alexa R; Mastin, Larry G; Herzog, Michael; Schwaiger, Hans F; Schneider, David J; Wallace, Kristi L; Clarke, Amanda B

    2015-01-01

    During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-characterized 'wet' eruption. The 2009 eruption of Redoubt Volcano, Alaska, incorporated water from the surface (in this case, a glacier), which is a common occurrence during explosive volcanism worldwide. Observations from C-band weather radar, fall deposits and numerical modelling demonstrate that hail-forming processes in the eruption plume triggered aggregation of ∼95% of the fine ash and stripped much of the erupted mass out of the atmosphere within 30 min. Based on these findings, we propose a mechanism of hail-like ash aggregation that contributes to the anomalously rapid fallout of fine ash and occurrence of concentrically layered aggregates in volcanic deposits. PMID:26235052

  16. Hail formation triggers rapid ash aggregation in volcanic plumes

    PubMed Central

    Van Eaton, Alexa R.; Mastin, Larry G.; Herzog, Michael; Schwaiger, Hans F.; Schneider, David J.; Wallace, Kristi L.; Clarke, Amanda B.

    2015-01-01

    During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-characterized ‘wet' eruption. The 2009 eruption of Redoubt Volcano, Alaska, incorporated water from the surface (in this case, a glacier), which is a common occurrence during explosive volcanism worldwide. Observations from C-band weather radar, fall deposits and numerical modelling demonstrate that hail-forming processes in the eruption plume triggered aggregation of ∼95% of the fine ash and stripped much of the erupted mass out of the atmosphere within 30 min. Based on these findings, we propose a mechanism of hail-like ash aggregation that contributes to the anomalously rapid fallout of fine ash and occurrence of concentrically layered aggregates in volcanic deposits. PMID:26235052

  17. Evaluation of quantitative satellite-based retrievals of volcanic ash clouds

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Pavolonis, M. J.; Bojinski, S.; Siddans, R.; Thomas, G.

    2015-12-01

    Volcanic ash clouds are a serious hazard to aviation, and mitigation requires a robust system of volcano monitoring, eruption detection, characterization of cloud properties, forecast of cloud movement, and communication of warnings. Several research groups have developed quantitative satellite-based volcanic ash products and some of these are in operational use by Volcanic Ash Advisory Centers around the world to aid in characterizing cloud properties and forecasting regions of ash hazard. The algorithms applied to the satellite data utilize a variety of techniques, and thus produce results that differ. The World Meteorological Organization has recently sponsored an intercomparison study of satellite-based retrievals with four goals: 1) to establish a validation protocol for satellite-based volcanic ash products, 2) to quantify and understand differences in products, 3) to develop best practices, and 4) to standardize volcanic cloud geophysical parameters. Six volcanic eruption cases were considered in the intercomparison: Eyjafallajökull, Grimsvötn, Kelut, Kirishimayama, Puyehue-Cordón Caulle, and Sarychev Peak. Twenty-four algorithms were utilized, which retrieved parameters including: ash cloud top height, ash column mass loading, ash effective radius, and ash optical depth at visible and thermal-infrared wavelengths. Results were compared to space-based, airborne, and ground-based lidars; complementary satellite retrievals; and manual "expert evaluation" of ash extent. The intercomparison results will feed into the International Civil Aviation Organization "Roadmap for International Airways Volcano Watch", which integrates volcanic meteorological information into decision support systems for aircraft operations.

  18. Characterizing uncertainty in the motion, future location and ash concentrations of volcanic plumes and ash clouds

    NASA Astrophysics Data System (ADS)

    Webley, P.; Patra, A. K.; Bursik, M. I.; Pitman, E. B.; Dehn, J.; Singh, T.; Singla, P.; Stefanescu, E. R.; Madankan, R.; Pouget, S.; Jones, M.; Morton, D.; Pavolonis, M. J.

    2013-12-01

    Forecasting the location and airborne concentrations of volcanic ash plumes and their dispersing clouds is complex and knowledge of the uncertainty in these forecasts is critical to assess and mitigate the hazards that could exist. We show the results from an interdisciplinary project that brings together scientists drawn from the atmospheric sciences, computer science, engineering, mathematics, and geology. The project provides a novel integration of computational and statistical modeling with a widely-used volcanic particle dispersion code, to provide quantitative measures of confidence in predictions of the motion of ash clouds caused by volcanic eruptions. We combine high performance computing and stochastic analysis, resulting in real time predictions of ash cloud motion that account for varying wind conditions and a range of model variables. We show how coupling a real-time model for ash dispersal, PUFF, with a volcanic eruption model, BENT, allows for the definition of the variability in the dispersal model inputs and hence classify the uncertainty that can then propagate for the ash cloud location and downwind concentrations. We additionally analyze the uncertainty in the numerical weather prediction forecast data used by the dispersal model by using ensemble forecasts and assess how this affects the downwind concentrations. These are all coupled together and by combining polynomical chaos quadrature with stochastic integration techniques, we provide a quantitative measure of the reliability (i.e. error) of those predictions. We show comparisons of the downwind height calculations and mass loadings with observations of ash clouds available from satellite remote sensing data. The aim is to provide a probabilistic forecast of location and ash concentration that can be generated in real-time and used by those end users in the operational ash cloud hazard assessment environment.

  19. Remote Sensing of Volcanic ASH at the Met Office

    NASA Astrophysics Data System (ADS)

    Marenco, F.; Kent, J.; Adam, M.; Buxmann, J.; Francis, P.; Haywood, J.

    2016-06-01

    The eruption of Eyjafjallajökull in 2010 has triggered the rapid development of volcanic ash remote sensing activities at the Met Office. Volcanic ash qualitative and quantitative mapping have been achieved using lidar on board the Facility for Airborne Atmospheric Measurements (FAAM) research aircraft, and using improved satellite retrieval algorithms. After the eruption, a new aircraft facility, the Met Office Civil Contingencies Aircraft (MOCCA), has been set up to enable a rapid response, and a network of ground-based remote sensing sites with lidars and sunphotometers is currently being developed. Thanks to these efforts, the United Kingdom (UK) will be much better equipped to deal with such a crisis, should it happen in the future.

  20. International Database of Volcanic Ash Impacts

    NASA Astrophysics Data System (ADS)

    Wallace, K.; Cameron, C.; Wilson, T. M.; Jenkins, S.; Brown, S.; Leonard, G.; Deligne, N.; Stewart, C.

    2015-12-01

    Volcanic ash creates extensive impacts to people and property, yet we lack a global ash impacts catalog to organize, distribute, and archive this important information. Critical impact information is often stored in ephemeral news articles or other isolated resources, which cannot be queried or located easily. A global ash impacts database would improve 1) warning messages, 2) public and lifeline emergency preparation, and 3) eruption response and recovery. Ashfall can have varying consequences, such as disabling critical lifeline infrastructure (e.g. electrical generation and transmission, water supplies, telecommunications, aircraft and airports) or merely creating limited and expensive inconvenience to local communities. Impacts to the aviation sector can be a far-reaching global issue. The international volcanic ash impacts community formed a committee to develop a database to catalog the impacts of volcanic ash. We identify three user populations for this database: 1) research teams, who would use the database to assist in systematic collection, recording, and storage of ash impact data, and to prioritize impact assessment trips and lab experiments 2) volcanic risk assessment scientists who rely on impact data for assessments (especially vulnerability/fragility assessments); a complete dataset would have utility for global, regional, national and local scale risk assessments, and 3) citizen science volcanic hazard reporting. Publication of an international ash impacts database will encourage standardization and development of best practices for collecting and reporting impact information. Data entered will be highly categorized, searchable, and open source. Systematic cataloging of impact data will allow users to query the data and extract valuable information to aid in the development of improved emergency preparedness, response and recovery measures.

  1. Artificial cloud test confirms volcanic ash detection using infrared spectral imaging.

    PubMed

    Prata, A J; Dezitter, F; Davies, I; Weber, K; Birnfeld, M; Moriano, D; Bernardo, C; Vogel, A; Prata, G S; Mather, T A; Thomas, H E; Cammas, J; Weber, M

    2016-01-01

    Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m(-3) were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft. PMID:27156701

  2. Artificial cloud test confirms volcanic ash detection using infrared spectral imaging

    PubMed Central

    Prata, A. J.; Dezitter, F.; Davies, I.; Weber, K.; Birnfeld, M.; Moriano, D.; Bernardo, C.; Vogel, A.; Prata, G. S.; Mather, T. A.; Thomas, H. E.; Cammas, J.; Weber, M.

    2016-01-01

    Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m−3 were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft. PMID:27156701

  3. Artificial cloud test confirms volcanic ash detection using infrared spectral imaging

    NASA Astrophysics Data System (ADS)

    Prata, A. J.; Dezitter, F.; Davies, I.; Weber, K.; Birnfeld, M.; Moriano, D.; Bernardo, C.; Vogel, A.; Prata, G. S.; Mather, T. A.; Thomas, H. E.; Cammas, J.; Weber, M.

    2016-05-01

    Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m‑3 were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft.

  4. Artificial cloud test confirms volcanic ash detection using infrared spectral imaging.

    PubMed

    Prata, A J; Dezitter, F; Davies, I; Weber, K; Birnfeld, M; Moriano, D; Bernardo, C; Vogel, A; Prata, G S; Mather, T A; Thomas, H E; Cammas, J; Weber, M

    2016-05-09

    Airborne volcanic ash particles are a known hazard to aviation. Currently, there are no means available to detect ash in flight as the particles are too fine (radii < 30 μm) for on-board radar detection and, even in good visibility, ash clouds are difficult or impossible to detect by eye. The economic cost and societal impact of the April/May 2010 Icelandic eruption of Eyjafjallajökull generated renewed interest in finding ways to identify airborne volcanic ash in order to keep airspace open and avoid aircraft groundings. We have designed and built a bi-spectral, fast-sampling, uncooled infrared camera device (AVOID) to examine its ability to detect volcanic ash from commercial jet aircraft at distances of more than 50 km ahead. Here we report results of an experiment conducted over the Atlantic Ocean, off the coast of France, confirming the ability of the device to detect and quantify volcanic ash in an artificial ash cloud created by dispersal of volcanic ash from a second aircraft. A third aircraft was used to measure the ash in situ using optical particle counters. The cloud was composed of very fine ash (mean radii ~10 μm) collected from Iceland immediately after the Eyjafjallajökull eruption and had a vertical thickness of ~200 m, a width of ~2 km and length of between 2 and 12 km. Concentrations of ~200 μg m(-3) were identified by AVOID at distances from ~20 km to ~70 km. For the first time, airborne remote detection of volcanic ash has been successfully demonstrated from a long-range flight test aircraft.

  5. Insight of the fusion behavior of volcanic ash: Implications for Volcanic ash Hazards to Aircraft Safety

    NASA Astrophysics Data System (ADS)

    Song, Wenjia; Hess, Kai-Uwe; Küppers, Ulrich; Scheu, Bettina; Cimarelli, Corrado; Lavallée, Yan; Sohyun, Park; Gattermann, Ulf; Müller, Dirk; Dingwell, Donald Bruce

    2014-05-01

    The interaction of volcanic ash with jet turbines during via ingestion of ash into engines operating at supra-volcanic temperatures is widely recognized as a potentially fatal hazard for jet aircraft. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The fusibility of volcanic ash is believed to impact strongly its deposition in the hotter parts of jet engines. Despite this, explicit investigation of ash sintering using standardized techniques is in its infancy. Volcanic ash may vary widely in its physical state and chemical composition between and even within explosive volcanic eruptions. Thus a comparative study of the fusibility of ash which involves a standard recognized techniques would be highly desirable. In this work, nine samples of fine ash, deposited from co-pyroclastic offrom nine different volcanoes which cover a broad range of chemical composition, were investigated. Eight of them were collected from 2001-2009 eruptions. Because of the currently elevated level of eruptive activity and its potential hazards to aircraft safety and the remaining one sample was collected from a 12,121 ± 114 yr B.P. eruption. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the fusion phenomena as well as determine the volcanic ash melting behavior by defining four characteristic temperatures (shrinkage temperature, deformation temperature, hemispherical temperature, and flow temperature) by means of heating microscope instrument and different thermal analysis methods. Here, we find that there are similar sticking ability and flow behavior of

  6. Marine Mesocosm Bacterial Colonisation of Volcanic Ash

    NASA Astrophysics Data System (ADS)

    Witt, V.; Cimarelli, C.; Ayris, P. M.; Kueppers, U.; Erpenbeck, D.; Dingwell, D. B.; Woerheide, G.

    2014-12-01

    Explosive volcanic eruptions regularly eject large quantities of ash particles into the atmosphere, which can be deposited via fallout into oceanic environments. Such fallout has the potential to alter pH, light and nutrient availability at local or regional scales. Shallow-water coral reef ecosystems - "rainforests of the sea" - are highly sensitive to disturbances, such as ocean acidification, sedimentation and eutrophication. Therefore, ash deposition may lead to burial and mortality of such reefs. Coral reef ecosystem resilience may depend on pioneer bacterial colonisation of the ash layer, supporting subsequent establishment of the micro- and ultimately the macro-community. However, it is currently unknown which bacteria are involved in pioneer colonisation. We hypothesize that physico-chemical properties (i.e., morphology, chemistry, mineralogy) of the ash may dictate bacterial colonisation. We have tested the effect of substrate properties on bacterial diversity and abundance colonising five substrates: i) quartz sand ii) crystalline ash from the Sakurajima volcano (Japan) iii) volcanic glass iv) carbonate reef sand and v) calcite sand of similar grain size - by incubation in a controlled marine mesocosm (coral reef aquarium) under low light conditions for three months. Bacterial communities were screened every month by Automated Ribosomal Intergenic Spacer Analysis of the 16S-23S rRNA Internal Transcribed Spacer region. Multivariate statistics revealed discrete groupings of bacterial communities on substrates of volcanic origin (ash and glass) and reef origin (three sands). Analysis Of Similarity supports significantly different communities associated with all substrates (p=0.0001), only quartz did not differ from both carbonate and calcite sands. The ash substrate exhibited the most diverse bacterial community and carried the most substrate-specific bacterial operational taxonomic units. Our findings suggest that bacterial diversity and community

  7. Reference dataset of volcanic ash physicochemical and optical properties for atmospheric measurement retrievals and transport modelling

    NASA Astrophysics Data System (ADS)

    Vogel, Andreas; Durant, Adam; Sytchkova, Anna; Diplas, Spyros; Bonadonna, Costanza; Scarnato, Barbara; Krüger, Kirstin; Kylling, Arve; Kristiansen, Nina; Stohl, Andreas

    2016-04-01

    Explosive volcanic eruptions emit up to 50 wt.% (total erupted mass) of fine ash particles (<63 microns), which individually can have theoretical atmospheric lifetimes that span hours to days. Depending on the injection height, fine ash may be subsequently transported and dispersed by the atmosphere over 100s - 1000s km and can pose a major threat for aviation operations. Recent volcanic eruptions, such as the 2010 Icelandic Eyjafjallajökull event, illustrated how volcanic ash can severely impact commercial air traffic. In order to manage the threat, it is important to have accurate forecast information on the spatial extent and absolute quantity of airborne volcanic ash. Such forecasts are constrained by empirically-derived estimates of the volcanic source term and the nature of the constituent volcanic ash properties. Consequently, it is important to include a quantitative assessment of measurement uncertainties of ash properties to provide realistic ash forecast uncertainty. Currently, information on volcanic ash physicochemical and optical properties is derived from a small number of somewhat dated publications. In this study, we provide a reference dataset for physical (size distribution and shape), chemical (bulk vs. surface chemistry) and optical properties (complex refractive index in the UV-vis-NIR range) of a representative selection of volcanic ash samples from 10 different volcanic eruptions covering the full variability in silica content (40-75 wt.% SiO2). Through the combination of empirical analytical methods (e.g., image analysis, Energy Dispersive Spectroscopy, X-ray Photoelectron Spectroscopy, Transmission Electron Microscopy and UV/Vis/NIR/FTIR Spectroscopy) and theoretical models (e.g., Bruggeman effective medium approach), it was possible to fully capture the natural variability of ash physicochemical and optical characteristics. The dataset will be applied in atmospheric measurement retrievals and atmospheric transport modelling to determine

  8. Ash iron mobilization in volcanic eruption plumes

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, G.; Hort, M.; Langmann, B.

    2014-12-01

    It has been shown that volcanic ash fertilizes the Fe-limited areas of the surface ocean through releasing soluble iron. As ash iron is mostly insoluble upon the eruption, it is hypothesized that heterogeneous in-plume and in-cloud processing of the ash promote the iron solubilization. Direct evidences concerning such processes are, however, lacking. In this study, a 1-D numerical model is developed to simulate the physicochemical interactions of gas-ash-aerosol in volcanic eruption plumes focusing on the iron mobilization processes at temperatures between 600 and 0 °C. Results show that sulfuric acid and water vapor condense at ~150 and ~50 °C on the ash surface, respectively. This liquid phase then efficiently scavenges the surrounding gases (>95% of HCl, 3-20% of SO2 and 12-62% of HF) forming an extremely acidic coating at the ash surface. The low pH conditions of the aqueous film promote acid-mediated dissolution of the Fe-bearing phases present in the ash material. We estimate that 0.1 to 33% of the total iron available at the ash surface is dissolved in the aqueous phase before the freezing point is reached. The efficiency of dissolution is controlled by the halogen content of the erupted gas as well as the mineralogy of the iron at ash surface: elevated halogen concentrations and presence of Fe2+-carrying phases lead to the highest dissolution efficiency. Findings of this study are in agreement with the data obtained through leaching experiments.

  9. Laboratory Studies of Ice Nucleation on Volcanic Ash

    NASA Astrophysics Data System (ADS)

    Tolbert, M. A.; Schill, G. P.; Genareau, K. D.

    2014-12-01

    Ice nucleation on volcanic ash controls both ash aggregation and cloud glaciation, which affect human respiratory health, atmospheric transport, and global climate. We have performed laboratory studies of the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman Microscopy coupled to an environmental cell. Ash from the Fuego (Basaltic Ash, Guatemala), Soufriere Hills (Andesetic Ash, Montserrat), and Taupo (Rhyolitic Ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. We find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice at ice saturation ratios of 1.05 ± 0.1. For immersion freezing, however, only the Taupo ash exhibited efficient heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

  10. The adsorption of HCl on volcanic ash

    NASA Astrophysics Data System (ADS)

    Gutiérrez, Xochilt; Schiavi, Federica; Keppler, Hans

    2016-03-01

    Understanding the interaction between volcanic gases and ash is important to derive gas compositions from ash leachates and to constrain the environmental impact of eruptions. Volcanic HCl could potentially damage the ozone layer, but it is unclear what fraction of HCl actually reaches the stratosphere. The adsorption of HCl on volcanic ash was therefore studied from -76 to +150 °C to simulate the behavior of HCl in the dilute parts of a volcanic plume. Finely ground synthetic glasses of andesitic, dacitic, and rhyolitic composition as well as a natural obsidian from Vulcano (Italy) served as proxies for fresh natural ash. HCl adsorption is an irreversible process and appears to increase with the total alkali content of the glass. Adsorption kinetics follow a first order law with rate constants of 2.13 ṡ10-6 s-1 to 1.80 ṡ10-4 s-1 in the temperature range investigated. For dacitic composition, the temperature and pressure dependence of adsorption can be described by the equation ln ⁡ c = 1.26 + 0.27 ln ⁡ p - 715.3 / T, where c is the surface concentration of adsorbed HCl in mg/m2, T is temperature in Kelvin, and p is the partial pressure of HCl in mbar. A comparison of this model with a large data set for the composition of volcanic ash suggests that adsorption of HCl from the gas phase at relatively low temperatures can quantitatively account for the majority of the observed Cl concentrations. The model implies that adsorption of HCl on ash increases with temperature, probably because of the increasing number of accessible adsorption sites. This temperature dependence is opposite to that observed for SO2, so that HCl and SO2 are fractionated by the adsorption process and the fractionation factor changes by four orders of magnitude over a temperature range of 250 K. The assumption of equal adsorption of different species is therefore not appropriate for deriving volcanic gas compositions from analyses of adsorbates on ash. However, with the experimental

  11. Satellite to model comparisons of volcanic ash emissions in the North Pacific

    NASA Astrophysics Data System (ADS)

    Steensen, Torge S.

    To detect, analyze and predict the movement of volcanic ash in real time, dispersion models and satellite remote sensing data are important. A combination of both approaches is discussed here to enhance the techniques currently used to quantify volcanic ash emissions, based on case studies of the eruptions of the Kasatochi (Alaska, USA, 2008), Mount Redoubt (Alaska, USA, 2009) and Sarychev Peak (Russia, 2009) volcanoes. Results suggest a quantitative approach determining masses from satellite images can be problematic due to uncertainties in knowledge of input values, most importantly the ground surface temperature required in the mass retrieval. Furthermore, a volcanic ash transport and dispersion model simulation requires its own set of accurate input parameters to forecast an ash cloud's future location. Such input parameters are often difficult to assess, especially in real time volcano monitoring, and default values are often used for simplification. The objective of this dissertation is to find a quantitative comparison technique to apply to satellite and volcanic ash transport and dispersion models that reduces the inherent uncertainty in the results. The binary `Ash - No Ash' approach focusing on spatial extent rather than absolute masses is suggested, where the ash extent in satellite data is quantitatively compared to that in the dispersion model's domain. In this technique, neither satellite data nor dispersion model results are regarded as the truth. The Critical Success Index (CSI) as well as Model and Satellite Excess values (ME and SE, respectively) are introduced as comparison tools. This approach reduces uncertainties in the analysis of airborne volcanic ash and, due to the reduced list of input parameters and assumptions in satellite and model data, the results will be improved. This decreased complexity of the analysis, combined with a reduced error as the defined edge of ash cloud is compared in each method rather than defined threshold or mass

  12. NRL Satellite Volcanic Ash Plume Monitoring

    NASA Astrophysics Data System (ADS)

    Hawkins, J.; Kuciauskas, A. P.; Richardson, K.; Solbrig, J.; Miller, S. D.; Pavolonis, M. J.; Bankert, R.; Lee, T.; Kent, J.; Tsui, T.

    2009-12-01

    The Naval Research Laboratory’s (NRL) Marine Meteorology Division (NRL-MRY) is assembling a unique suite of near real-time digital satellite products geared towards monitoring volcanic ash plumes which can create hazardous aviation conditions. Ash plume detection, areal extent, plume top height and mass loading will be extracted via automated algorithms from a combination of geostationary (GEO) and low earth orbiting (LEO) data sets that take advantage of their complimentary strengths since no one sensor has the required spectral, spatial and temporal attributes needed. This product suite would then be available to the Volcanic Ash Advisory Centers (VAAC) and other interested users via web distribution. Initially, GOES-West and the Japanese MTSAT data will be incorporated to view volcanic plumes within the north Pacific region. Although GEO sensor spectral channels are not optimized for ash detection, temporal changes over limited timeframes can assist in plume extraction, but not for those at the highest latitudes. Examples with multi-channel techniques will be highlighted via animations. LEO sensors provide a suite of spectral channels unmatched on GEO platforms and permit enhanced ash plume monitoring. NRL has exploited the Moderate Resolution Imaging Spectroradiometer (MODIS) and SeaWiFS via a “dust enhancement technique” that has demonstrated positive plume monitoring results. Multi-channel methods using the Advanced Very High Resolution Radiometer (AVHRR) will be highlighted to take advantage of the numerous NOAA LEO satellites carrying this wide swath sensor with frequent volcano overpasses at the higher latitudes. The DMSP Operational Linescan System (OLS) provides daytime visible/infrared, as well as night time visible data which has shown value in spotting ash plumes when sufficient lunar illumination is present. The following suite of products is potentially available for over twenty (20) volcano sites world-wide via our NexSat web site: http

  13. Laboratory study of volcanic ash electrification

    NASA Astrophysics Data System (ADS)

    Alois, Stefano; Merrison, Jonathan

    2016-04-01

    Electrostatic forces play an important role in the dynamics of volcanic plumes, for example in ash dispersion and aggregation phenomena. Field measurements of ash electrification are often technically challenging due to poor access and there lacks an accepted physical theory to describe the electrical charge exchange which occurs during particle contact. The goal of the study is to investigate single particle electrification under controlled conditions using advanced laboratory facilities. A novel technique is presented, based on the use of a laser based velocimeter. Here an electric field is applied and the field-induced drift velocity of (micron-sized) ash grains is measured as well as the particles fall velocity. This allows the simultaneous determination of a suspended grains size and electrical charge. The experiments are performed in a unique environmental wind tunnel facility under controlled low-pressure conditions. Preliminary results of particle electrification will be presented.

  14. Chemical processing of volcanic ash within eruption plume and cloud: a numerical modeling approach

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, Gholam Ali; Hort, Matthias; Langmann, Baerbel; Brasseur, Guy

    2015-04-01

    Volcanic ash is recently identified as an active chemical agent in the Earth system. Generated mainly through lithospheric processes and magma fragmentation, it can pose significant impacts upon different components of the Earth system for e.g. atmosphere and hydrosphere on various temporal and spatial scales. While airborne in the atmosphere, transition metals contained in the ash can catalyze the sulfur oxidation cycle thereby indirectly affecting the volcanic radiative forcing. Moreover, upon deposition on the surface ocean, ash can release soluble iron that fertilizes Fe-limited areas of the ocean and stimulate the marine productivity and CO2 drawdown. Such impacts are provoked through interfacial processes and thus, are mainly induced by the ash surface composition. Recent studies suggest that in-plume and in-cloud processing of volcanic ash primarily control its surface composition. Direct evidences concerning such processes are, however, lacking. Here we present the results of our recent investigations on in-plume and in-cloud processing of volcanic ash. A 1D numerical model is developed that simulates the gas-ash-aerosol interactions in volcanic eruption plume and cloud at temperatures between 600 C and 0 C focusing on iron, sulfur and halogen chemistry. Results show that sulfuric acid and water vapor condense at 150 C and 50 C, respectively, generating a liquid coating at the ash surface that scavenges the surrounding gases (>95extremely acidic (pH

  15. Quantitative shape measurements of distal volcanic ash

    NASA Astrophysics Data System (ADS)

    Riley, Colleen M.; Rose, William I.; Bluth, Gregg J. S.

    2003-10-01

    Large-scale volcanic eruptions produce fine ash (<200 μm) which has a long atmospheric residence time (1 hour or more) and can be transported great distances from the volcanic source, thus, becoming a hazard to aircraft and public health. Ash particles have irregular shapes, so data on particle shape, size, and terminal velocities are needed to understand how the irregular-shaped particles affect transport processes and radiative transfer measurements. In this study, a methodology was developed to characterize particle shapes, sizes, and terminal velocities for three ash samples of different compositions. The shape and size of 2500 particles from (1) distal fallout (˜100 km) of the 14 October 1974 Fuego eruption (basaltic), (2) the secondary maxima (˜250 km) of the 18 August 1992 Spurr eruption (andesitic), and (3) the Miocene Ash Hollow member, Nebraska (rhyolitic) were measured using image analysis techniques. Samples were sorted into 10 to 19 terminal velocity groups (0.6-59.0 cm/s) using an air elutriation device. Grain-size distributions for the samples were measured using laser diffraction. Aspect ratio, feret diameter, and perimeter measurements were found to be the most useful descriptors of how particle shape affects terminal velocity. These measurement values show particle shape differs greatly from a sphere (commonly used in models and algorithms). The diameters of ash particles were 10-120% larger than ideal spheres at the same terminal velocity, indicating that irregular particle shape greatly increases drag. Gas-adsorption derived surface areas are 1 to 2 orders of magnitude higher than calculated surface areas based on measured dimensions and simple geometry, indicating that particle shapes are highly irregular. Correction factors for surface area were derived from the ash sample measurements so that surface areas calculated by assuming spherical particle shapes can be corrected to reflect more realistic values.

  16. Isotopic paleoclimate from hydrated volcanic ash

    SciTech Connect

    Friedman, I.; Izett, G.A.; Gleason, J.D.

    1985-01-01

    The deuterium composition (deltaD) of secondary water in glass shards of volcanic ash can be used to calculate the deltaD--and hence the climatic association--of water that was in contact with the ash during the first 10,000 years after eruption of the ash; this being the approximate (+/-5000 years) time necessary for water to diffuse completely through the thin walls of the pumice and glass shards. The fractionation between environmental water and water diffusing into the glassy ash must be known in order to calculate the deltaD of the ancient ground water. With help from A.J. Gude and R.A. Sheppard, the authors have recently determined this fractionation, and have used it to derive a value for deltaD of water from 25 samples of glass from the Huckleberry Ridge (2.1 m.y.), Bishop Tuff (0.74 m.y.), and Lava Creek B (0.61 m.y.) ashes collected from sites throughout the Western US. All of these deltaD values correlate very well with latitude and with the present distribution of deltaD in surface water. For example, the deltaD of water in Huckleberry Ridge ash varies from -85 per thousand SMOW for samples collected in Texas, to -148 per thousand for samples from south-central Montana. Thus, water of hydration in rhyolitic ash represents samples of ancient environmental water and can be used to study changes in the deltaD of the precipitation through time.

  17. Filling the Gaps: The Synergistic Application of Satellite Data for the Volcanic Ash Threat to Aviation

    NASA Technical Reports Server (NTRS)

    Murray, John; Vernier, Jean-Paul; Fairlie, T. Duncan; Pavolonis, Michael; Krotkov, Nickolay A.; Lindsay, Francis; Haynes, John

    2013-01-01

    Although significant progress has been made in recent years, estimating volcanic ash concentration for the full extent of the airspace affected by volcanic ash remains a challenge. No single satellite, airborne or ground observing system currently exists which can sufficiently inform dispersion models to provide the degree of accuracy required to use them with a high degree of confidence for routing aircraft in and near volcanic ash. Toward this end, the detection and characterization of volcanic ash in the atmosphere may be substantially improved by integrating a wider array of observing systems and advancements in trajectory and dispersion modeling to help solve this problem. The qualitative aspect of this effort has advanced significantly in the past decade due to the increase of highly complementary observational and model data currently available. Satellite observations, especially when coupled with trajectory and dispersion models can provide a very accurate picture of the 3-dimensional location of ash clouds. The accurate estimate of the mass loading at various locations throughout the entire plume, however improving, remains elusive. This paper examines the capabilities of various satellite observation systems and postulates that model-based volcanic ash concentration maps and forecasts might be significantly improved if the various extant satellite capabilities are used together with independent, accurate mass loading data from other observing systems available to calibrate (tune) ash concentration retrievals from the satellite systems.

  18. The aggregation efficiency of very fine volcanic ash

    NASA Astrophysics Data System (ADS)

    Del Bello, E.; Taddeucci, J.; Scarlato, P.

    2013-12-01

    Explosive volcanic eruptions can discharge large amounts of very small sized pyroclasts (under 0.090 mm) into the atmosphere that may cause problems to people, infrastructures and environment. The transport and deposition of fine ash are ruled by aggregation that causes premature settling of fine ash and, as consequence, significantly reduces the concentration of airborne material over long distances. Parameterizing the aggregation potential of fine ash is then needed to provide accurate modelling of ash transport and deposition from volcanic plumes. Here we present the first results of laboratory experiments investigating the aggregation efficiency of very fine volcanic particles. Previous laboratory experiments have shown that collision kinetic and relative humidity provide the strongest effect on aggregation behaviour but were only limited to particles with size > 0.125 mm. In our work, we focus on natural volcanic ash at ambient humidity with particles size < 0.090 mm, by taking into account the effect of grain size distribution on aggregation potential. Two types of ash were used in our experiments: fresh ash, collected during fall-out from a recent plume-forming eruption at Sakurajima (Japan -July 2013) and old ash, collected from fall-out tephra deposits at Campi Flegrei (Italy, ca. 10 ka), to account for the different chemical composition and morphoscopic effects of altered ash on aggregation efficiency. Total samples were hand sieved to obtain three classes with unimodal grain size distributions (<0.090 mm, <0.063 mm, <0.032 mm). Bimodal grain size distributions were also obtained by mixing the three classes in different proportions. During each experiments, particles were sieved from the top of a transparent tank where a fan, placed at the bottom, allows turbulent dispersion of particles. Collision and sticking of particles on a vertical glass slide were filmed with a high speed cameras at 6000 fps. Our lenses arrangement provide high image resolution

  19. The Global Framework for Providing Information about Volcanic-Ash Hazards to International Air Navigation

    NASA Astrophysics Data System (ADS)

    Romero, R. W.; Guffanti, M.

    2009-12-01

    The International Civil Aviation Organization (ICAO) created the International Airways Volcano Watch (IAVW) in 1987 to establish a requirement for international dissemination of information about airborne ash hazards to safe air navigation. The IAVW is a set of operational protocols and guidelines that member countries agree to follow in order to implement a global, multi-faceted program to support the strategy of ash-cloud avoidance. Under the IAVW, the elements of eruption reporting, ash-cloud detecting, and forecasting expected cloud dispersion are coordinated to culminate in warnings sent to air traffic controllers, dispatchers, and pilots about the whereabouts of ash clouds. Nine worldwide Volcanic Ash Advisory Centers (VAAC) established under the IAVW have the responsibility for detecting the presence of ash in the atmosphere, primarily by looking at imagery from civilian meteorological satellites, and providing advisories about the location and movement of ash clouds to aviation meteorological offices and other aviation users. Volcano Observatories also are a vital part of the IAVW, as evidenced by the recent introduction of a universal message format for reporting the status of volcanic activity, including precursory unrest, to aviation users. Since 2003, the IAVW has been overseen by a standing group of scientific, technical, and regulatory experts that assists ICAO in the development of standards and other regulatory material related to volcanic ash. Some specific problems related to the implementation of the IAVW include: the lack of implementation of SIGMET (warning to aircraft in flight) provisions and delayed notifications of volcanic eruptions. Expected future challenges and developments involve the improvement in early notifications of volcanic eruptions, the consolidation of the issuance of SIGMETs, and the possibility of determining a “safe” concentration of volcanic ash.

  20. Testing exposure of a jet engine to a dilute volcanic-ash cloud

    NASA Astrophysics Data System (ADS)

    Guffanti, M.; Mastin, L. G.; Schneider, D. J.; Holliday, C. R.; Murray, J. J.

    2013-12-01

    An experiment to test the effects of volcanic-ash ingestion by a jet engine is being planned for 2014 by a consortium of U.S. Government agencies and engine manufacturers, under the auspices of NASA's Vehicle Integrated Propulsion Research Program. The experiment, using a 757-type engine, will be an on-ground, on-wing test carried out at Edwards Air Force Base, California. The experiment will involve the use of advanced jet-engine sensor technology for detecting and diagnosing engine health. A primary test objective is to determine the effect on the engine of many hours of exposure to ash concentrations (1 and 10 mg/cu m) representative of ash clouds many 100's to >1000 km from a volcanic source, an aviation environment of great interest since the 2010 Eyjafjallajökull, Iceland, eruption. A natural volcanic ash will be used; candidate sources are being evaluated. Data from previous ash/aircraft encounters, as well as published airborne measurements of the Eyjafjallajökull ash cloud, suggest the ash used should be composed primarily of glassy particles of andesitic to rhyolitic composition (SiO2 of 57-77%), with some mineral crystals, and a few tens of microns in size. Collected ash will be commercially processed less than 63 microns in size with the expectation that the ash particles will be further pulverized to smaller sizes in the engine during the test. For a nominally planned 80 hour test at multiple ash-concentration levels, the test will require roughly 500 kg of processed (appropriately sized) ash to be introduced into the engine core. Although volcanic ash clouds commonly contain volcanic gases such as sulfur dioxide, testing will not include volcanic gas or aerosol interactions as these present complex processes beyond the scope of the planned experiment. The viscous behavior of ash particles in the engine is a key issue in the experiment. The small glassy ash particles are expected to soften in the engine's hot combustion chamber, then stick to cooler

  1. Monitoring of volcanic emissions of SO2 and ash

    NASA Astrophysics Data System (ADS)

    Theys, Nicolas; Clarisse, Lieven; Brenot, Hugues; van Gent, Jeroen; Campion, Robin; van der A, Ronald; Valks, Pieter; Corradini, Stefano; Merucci, Luca; Van Roozendael, Michel; Coheur, Pierre-François; Hurtmans, Daniel; Clerbaux, Cathy; Tait, Steve; Ferrucci, Fabrizio

    2013-04-01

    Volcanic eruptions can emit large quantities of fine particles (ash) into the atmosphere as well as several trace gases, such as water vapour, carbon dioxide, sulphur species (SO2, H2S) and halogens (HCl, HBr, HF). These volcanic ejecta can have a considerable impact on the atmosphere, human health and society. Volcanic ash in particular is known to be a major threat for aviation, especially after dispersion over long distances (>1000 km) from the erupting volcano. In this respect, the continuous monitoring of volcanic ash from space is playing an essential role for the mitigation of aviation hazards. Compared to ash, SO2 is less critical for aviation safety, but is much easier to measure. Therefore, SO2 observations are often use as a marker of volcanic ash in the atmosphere. Moreover, SO2 yields information on the processes occurring in the magmatic system and is used as a proxy for the eruptive rate. In this presentation we give an overview of recent developments of the Support to Aviation Control Service (SACS). The focus is on the near-real time detection and monitoring of volcanic plumes of ash and SO2 using polar-orbiting instruments GOME-2, OMI, IASI and AIRS. The second part of the talk is dedicated to the determination of volcanic SO2 fluxes from satellite measurements. We review different techniques and investigate the temporal evolution of the total emissions of SO2 for recent volcanic events.

  2. Respiratory Health Effects of Volcanic Ash - a new Approach

    NASA Astrophysics Data System (ADS)

    Horwell, C. J.; Fenoglio, I.; Sparks, R. J.; Ragnarsdottir, K. V.; Fubini, B.

    2003-12-01

    Attempts to characterise the toxicity of volcanic ash have focused on the presence of the crystalline silica polymorph cristobalite, which is known to cause silicosis and lung cancer in industrial settings. Within the lung, it is the surface of the particles which will react with endogenous molecules. Free radicals, produced on particle surfaces, can react with DNA and other cellular components, instigating a chain of toxic events. For the first time, the ability of volcanic ash to form free radicals has been assessed using Electron Paramagnetic Resonance techniques specific to the hydroxyl radical. Respirable (< 4 microns) crystalline silica, separated from volcanic ash from the Soufriere Hills volcano, Montserrat, West Indies, did not produce hydroxyl free radicals or surface radicals. However, the ash, itself, generated up to 3 times more hydroxyl radicals than a quartz of known toxicity. The cause of the reactivity is reduced iron on the surface of iron-rich minerals such as amphiboles and pyroxenes. Fresh volcanic ash generates more free radicals than weathered volcanic ash which will have oxidised (and leached away) surface iron. These results have implications for volcanic health hazard research as it was previously assumed that volcanoes which did not produce respirable crystalline silica presented a lesser respiratory health hazard. The International Volcanic Health Hazard Network (IVHHN) promotes research into the health effects of volcanic emissions. Under the auspices of IVHHN, volcanic ash samples from volcanoes world-wide are being analysed for surface reactivity, grain-size distribution and composition to form a comprehensive database for use by volcano observatories, emergency managers, medical practitioners and researchers. The results will highlight volcanoes which have the potential to cause a respiratory health hazard through generation of iron-catalysed free radicals, as well as more conventional markers such as concentration of respirable

  3. Volcanic ash plume identification using polarization lidar: Augustine eruption, Alaska

    USGS Publications Warehouse

    Sassen, Kenneth; Zhu, Jiang; Webley, Peter W.; Dean, K.; Cobb, Patrick

    2007-01-01

    During mid January to early February 2006, a series of explosive eruptions occurred at the Augustine volcanic island off the southern coast of Alaska. By early February a plume of volcanic ash was transported northward into the interior of Alaska. Satellite imagery and Puff volcanic ash transport model predictions confirm that the aerosol plume passed over a polarization lidar (0.694 mm wavelength) site at the Arctic Facility for Atmospheric Remote Sensing at the University of Alaska Fairbanks. For the first time, lidar linear depolarization ratios of 0.10 – 0.15 were measured in a fresh tropospheric volcanic plume, demonstrating that the nonspherical glass and mineral particles typical of volcanic eruptions generate strong laser depolarization. Thus, polarization lidars can identify the volcanic ash plumes that pose a threat to jet air traffic from the ground, aircraft, or potentially from Earth orbit.

  4. Iron-induced hydroxyl radical generation from basaltic volcanic ash

    NASA Astrophysics Data System (ADS)

    Horwell, C. J.; Fenoglio, I.; Fubini, B.

    2007-09-01

    Iron-induced hydroxyl radical generation from the surface of volcanic ash particles is a possible mechanism of respiratory toxicity in addition to crystalline silica induced pathogenicity. Here we show that volcanic ash generates hydroxyl radicals, with greater reactivity in iron-rich, silica-poor samples, such as basaltic ash. Basaltic particles expose at the surface high levels of poorly-coordinated iron ions in both Fe(II) and Fe(III) oxidation states which are likely to be the cause of such reactivity. Hitherto, basaltic ash has been disregarded as a hazard due to the lack of crystalline silica particulate but future hazard assessment should consider its toxic potential.

  5. SO2 as a possible proxy for volcanic ash in aviation hazard avoidance

    NASA Astrophysics Data System (ADS)

    Sears, T. M.; Thomas, G. E.; Carboni, E.; Smith, A. J. A.; Grainger, R. G.

    2013-06-01

    Airborne volcanic ash poses a significant danger to aircraft, but is difficult to quantify accurately using satellite data, while sulphur dioxide is much easier to detect accurately, but is much less of a direct hazard to aviation. This paper investigates the reliability of using SO2 as a proxy for the location of volcanic ash, using an SO2 retrieval from the Infrared Atmospheric Sounding Interferometer (IASI) and ash detections from IASI and the Advanced Along Track Scanning Radiometer (AATSR). Using a numerical "missed ash fraction" applied to the eruptions of Eyjafjallajökull in 2010 and Puyehue-Cordón Caulle in 2011 reveals that the SO2 flag typically misses ˜30% of the detectable ash. Furthermore, the missed ash fraction is found to be highly variable, both between the two eruptions and over the course of each eruption, with values of over 80% found on some days. The detection threshold of the AATSR ash flag is also investigated using radiative transfer calculations, allowing the threshold of the IASI flag to be inferred, and these are related to the ash contamination levels.

  6. Strong responses of Southern Ocean phytoplankton communities to volcanic ash

    NASA Astrophysics Data System (ADS)

    Browning, T. J.; Bouman, H. A.; Henderson, G. M.; Mather, T. A.; Pyle, D. M.; Schlosser, C.; Woodward, E. M. S.; Moore, C. M.

    2014-04-01

    Volcanic eruptions have been hypothesized as an iron supply mechanism for phytoplankton blooms; however, little direct evidence of stimulatory responses has been obtained in the field. Here we present the results of twenty-one 1-2 day bottle enrichment experiments from cruises in the South Atlantic and Southern Ocean which conclusively demonstrated a photophysiological and biomass stimulation of phytoplankton communities following supply of basaltic or rhyolitic volcanic ash. Furthermore, experiments in the Southern Ocean demonstrated significant phytoplankton community responses to volcanic ash supply in the absence of responses to addition of dissolved iron alone. At these sites, dissolved manganese concentrations were among the lowest ever measured in seawater, and we therefore suggest that the enhanced response to ash may have been a result of the relief of manganese (co)limitation. Our results imply that volcanic ash deposition events could trigger extensive phytoplankton blooms, potentially capable of significant impacts on regional carbon cycling.

  7. Atmospheric fate and transport of fine volcanic ash: Does particle shape matter?

    NASA Astrophysics Data System (ADS)

    White, C. M.; Allard, M. P.; Klewicki, J.; Proussevitch, A. A.; Mulukutla, G.; Genareau, K.; Sahagian, D. L.

    2013-12-01

    Volcanic ash presents hazards to infrastructure, agriculture, and human and animal health. In particular, given the economic importance of intercontinental aviation, understanding how long ash is suspended in the atmosphere, and how far it is transported has taken on greater importance. Airborne ash abrades the exteriors of aircraft, enters modern jet engines and melts while coating interior engine parts causing damage and potential failure. The time fine ash stays in the atmosphere depends on its terminal velocity. Existing models of ash terminal velocities are based on smooth, quasi-spherical particles characterized by Stokes velocity. Ash particles, however, violate the various assumptions upon which Stokes flow and associated models are based. Ash particles are non-spherical and can have complex surface and internal structure. This suggests that particle shape may be one reason that models fail to accurately predict removal rates of fine particles from volcanic ash clouds. The present research seeks to better parameterize predictive models for ash particle terminal velocities, diffusivity, and dispersion in the atmospheric boundary layer. The fundamental hypothesis being tested is that particle shape irreducibly impacts the fate and transport properties of fine volcanic ash. Pilot studies, incorporating modeling and experiments, are being conducted to test this hypothesis. Specifically, a statistical model has been developed that can account for actual volcanic ash size distributions, complex ash particle geometry, and geometry variability. Experimental results are used to systematically validate and improve the model. The experiments are being conducted at the Flow Physics Facility (FPF) at UNH. Terminal velocities and dispersion properties of fine ash are characterized using still air drop experiments in an unconstrained open space using a homogenized mix of source particles. Dispersion and sedimentation dynamics are quantified using particle image

  8. A Quaternary volcanic ash deposit in western Missouri

    SciTech Connect

    Emerson, J.W. )

    1993-03-01

    Quaternary volcanic ash has been found in more than fifty localities in the midwest. The most widespread deposits originated from the Long Valley caldera, California; the Jemez calderas, New Mexico; or the Yellowstone caldera, Wyoming. Fission track dating has grouped the deposits into six separate ash falls ranging from 700,000--2,000,000 years old. A small volcanic ash deposit in western Missouri may be correlative with those found along the Kansas and Marais de Cygnes rivers in eastern Kansas. The ash deposit is in Northwest Bates County Missouri, exposed along a tributary to Miami Creek, four miles east of the Kansas state line. The ash layer is interbedded with alluvial terrace deposits and ranges from fifteen to thirty inches in thickness. It is inferred to have been deposited in a pond or oxbow lake. The color is white with a pale yellow tinge (Munsell 10YR 8/2). Shard examination shows that about 70% are flat bubble-wall types, about 20% have straight ridges, less than 10% are bubble-junction, and only a trace are vesicular. The closest known volcanic ash occurrence is an ash outcropping in a Kansas river terrace near DeSoto, KS, forty-five miles to the northwest. The DeSoto deposit has been identified as the .62 m.y. Lava Creek B ash from the Yellowstone caldera. A preliminary correlation of the Missouri ash with the DeSoto ash is based on similar shard morphology and color.

  9. International collaboration between Volcanic Ash Advisory Centers: Geospatially enabled tools to ensure forecast harmonization across global air routes

    NASA Astrophysics Data System (ADS)

    Osiensky, J. M.; Moore, D.; Kibler, J.; Bensimon, D.

    2013-12-01

    Volcanic plumes and drifting ash clouds pose a risk to flight operations somewhere across the globe every day. Airborne ash plumes pose a significant hazard to aircraft and timely and accurate forecasts greatly help mitigate the risk of an encounter. The world's nine (9) Volcanic Ash Advisory Centers (VAACs) provide products and services to address the volcanic ash hazard to aviation. These nine centers are operated by the meteorological authority within the state in which they are located. Each VAAC has its unique set of tools and procedures on how the data will be captured, displayed, analyzed and turned into a suite of products. The end products (e.g. Volcanic Ash Advisories (VAA) and Volcanic Ash Graphic (VAG)) are standardized through the International Civil Aviation Organization's International Airways Volcano Watch Operations Group (ICAO IAVWOPSG). Improvements in methods of collaboration between the VAACs are needed to allow for a seamless global harmonization of volcanic ash products. A geospatially enabled tool would allow for a common operating platform, data sharing, and situational awareness. The North American VAACs have been testing a capability to provide this environment to make forecast collaboration simple across the globe. This presentation highlights work that has been done to demonstrate this capability.

  10. Volcanic ash concentration during the 12 August 2011 Etna eruption

    NASA Astrophysics Data System (ADS)

    Scollo, Simona; Boselli, Antonella; Coltelli, Mauro; Leto, Giuseppe; Pisani, Gianluca; Prestifilippo, Michele; Spinelli, Nicola; Wang, Xuan

    2015-04-01

    Mount Etna, in Italy, is one of the most active volcanoes in the world and an ideal laboratory to improve volcano ash monitoring and forecasting. During the volcanic episode on 12 August 2011, an eruption column rose up to several kilometers above sea level (asl), and the volcanic plume dispersed to the southeast. From the video-surveillance system, we were able to estimate variations in the column height (peak value of 9.5 ± 0.5 km above sea level) with time. We derived the time-varying discharge rate (peak value of 60 m3 s-1) and determined the ash concentration using a volcanic ash dispersal model. The modeled ash concentration was compared with lidar measurements using different particle effective radius, and differences are within the error bars. Volcanic ash concentrations range from 0.5 to 35.5 × 10-3 g m-3. The comparison highlights that to improve volcanic ash forecasting during volcanic crises it is necessary to take into account the time-varying discharge rate of explosive eruptions.

  11. Volcanic and atmospheric controls on ash iron solubility: A review

    NASA Astrophysics Data System (ADS)

    Ayris, Paul; Delmelle, Pierre

    2012-01-01

    The ash material produced by volcanic eruptions carries important information about the underground magma eruptive conditions and subsequent modifications in the volcanic plume and during atmospheric transport. Volcanic ash is also studied because of its impacts on the environment and human health. In particular, there is a growing interest from a multidisciplinary scientific community to understand the role that ash deposition over open ocean regions may play as a source of bioavailable Fe for phytoplankton production. Similar to aeolian mineral dust, the processes that affect the mineralogy and speciation of Fe in ash may promote solubilisation of Fe in ash, and thus may increase the amount of volcanic Fe supplied to ocean surface waters. Our knowledge of these controls is still very limited, a situation which has hindered quantitative interpretation of experimental Fe release measurements. In this review, we identify the key volcanic and atmospheric controls that are likely to modulate ash Fe solubility. We also briefly discuss existing data on Fe release from ash and make some recommendations for future studies in this area.

  12. Exploiting hyperspectral sounders for volcanic ash remote sensing

    NASA Astrophysics Data System (ADS)

    Western, Luke; Watson, Matthew; Francis, Peter

    2016-04-01

    Assumptions are made when retrieving properties of volcanic ash clouds using passive infrared satellite remote sensing. Assumptions in the retrieval method lead to larger uncertainties in the retrieved volcanic ash cloud properties. It is a general desire to reduce these uncertainties by removing some of the assumptions that must be made. Hyperspectral sounders provide the spectral capabilities to explore many of the physical parameters that describe volcanic ash clouds - the question is, which parameters is it possible to retrieve? We show that using the Infrared Atmospheric Sounding Interferometer (IASI) it is possible to retrieve the mass column loading and cloud top pressure of a volcanic ash cloud, together with the effective radius and spread of the ash particle size distribution, as well as the cloud top pressure of any underlying water cloud using an optimal estimation technique. We discuss the capabilities and shortcomings of the method. The consideration of an underlying water cloud is of importance for improving retrievals, and we place a particular focus on how well the particle size distribution can be described. More specifically, we investigate the viability of using either a lognormal or a gamma distribution to describe the distribution of ash particles, and we show that it is possible to retrieve information about the spread of a lognormal distribution of particles, whereas it is not for a gamma distribution. Some preliminary conclusions on the size distribution of volcanic ash are presented.

  13. Traumatic Inhalation due to Merapi Volcanic Ash.

    PubMed

    Trisnawati, Ika; Budiono, Eko; Sumardi; Setiadi, Andang

    2015-07-01

    Pneumonoultramicroscopicsilicovolcanoconiosis is fibrotic lung diseases of the pulmonary parenchyma following chronic inhalation of inorganic dusts containing crystalline silicon dioxide. The acute manifestations observed after heavy ashfalls include attacks of asthma and bronchitis, with an increased reporting of cough, breathlessness, chest tightness, and wheezing due to irritation of the lining of the airways. The chronic health condition of most concern is silicosis, a diffuse nodular fibrosis of the lungs, develops slowly, usually appearing 10 to 30 years after first exposure. A 35 years old male was admitted to Sardjito Hospital, Yogyakarta with complaints of progressive dyspnoea, right side chest pain since last 3 month and periodic episodes of dry cough. He had history of exposure to volcanic ash at the location around volcano eruption for about 10 month. Examination revealed hyperresonant note, diminished vesicular breath sounds in lower right side of the chest. The chest X-ray presence leads to bleb. Based on the clinical and radiological suspicion of pneumoconiosis the patient was submitted to computed tomography of the chest and revealed bilateral multiple bullae mainly at the right lung field. The biopsy specimen verified the diagnosis of anthrocosilicosis. There is no proven specific therapy for any form of silicosis. Symptomatic therapy should include treatment of airflow limitation with bronchodilators, aggressive management of respiratory tract infection with antibiotics, and use of supplemental oxygen (if indicated) to prevent complications of chronic hypoxemia. PMID:26586390

  14. Volcanic Ash a Sink for Atmospheric Trace Species? A Laboratory Study of SO2 and O3 Uptake by Ash

    NASA Astrophysics Data System (ADS)

    Maters, E. C.; Delmelle, P.; Rossi, M. J.

    2015-12-01

    The impacts of volcanic activity on atmospheric chemistry have dominantly been viewed in relation to sulphur and halogen gas and aerosol emissions, while volcanic ash has been largely overlooked. However, solid particles in the atmosphere are increasingly recognised to be important in providing surfaces for heterogeneous reaction with trace gases such as SO2, NOx, O3 and organic compounds. Average annual emissions of ash, the <2 mm aluminosilicate particles generated during explosive eruptions, correspond to a surface area roughly equivalent to one-third to one-half of Earth's geometric surface area. Despite the substantial surface presented by airborne ash particles, interactions between ash and gases at ambient temperature have seldom been investigated. Laboratory studies with volcanic ash similar to those conducted with mineral dust from arid and semi-arid regions are much needed to understand and quantify the kinetics and mechanisms involved in heterogeneous reactions. Addressing this gap in knowledge is fundamental to better assess the capacity of ash emissions to affect atmospheric chemistry. We determined the initial uptake coefficient (γM) and the total uptake capacity (NiM) for gaseous SO2 and O3 by a compositional range of ash and glass powders in a Knudsen flow reactor. The volcanic materials exhibited γSO2 and NiSO2 values ranging from 10-3 to 10-2 and from 1011 to 1013 molecules cm-2, respectively. The solids samples also showed γO3 and NiO3 values ranging from 10-3 to 10-2 and from 1012 to 1013 molecules cm-2, respectively. Results of sequential exposure trials (SO2 then O3, O3 then SO2) suggest that SO2 and O3 do not compete for surface sites on the aluminosilicate materials, although O3 may participate in redox reactions with surface adsorbed sulphur species, enhancing the total capacity for O3 uptake by the solid. Differences in reactivity of the samples towards SO2 and O3 may be interpreted in light of variations in types and abundances of

  15. Improved prediction and tracking of volcanic ash clouds

    USGS Publications Warehouse

    Webley, P.; Mastin, L.

    2009-01-01

    During the past 30??years, more than 100 airplanes have inadvertently flown through clouds of volcanic ash from erupting volcanoes. Such encounters have caused millions of dollars in damage to the aircraft and have endangered the lives of tens of thousands of passengers. In a few severe cases, total engine failure resulted when ash was ingested into turbines and coating turbine blades. These incidents have prompted the establishment of cooperative efforts by the International Civil Aviation Organization and the volcanological community to provide rapid notification of eruptive activity, and to monitor and forecast the trajectories of ash clouds so that they can be avoided by air traffic. Ash-cloud properties such as plume height, ash concentration, and three-dimensional ash distribution have been monitored through non-conventional remote sensing techniques that are under active development. Forecasting the trajectories of ash clouds has required the development of volcanic ash transport and dispersion models that can calculate the path of an ash cloud over the scale of a continent or a hemisphere. Volcanological inputs to these models, such as plume height, mass eruption rate, eruption duration, ash distribution with altitude, and grain-size distribution, must be assigned in real time during an event, often with limited observations. Databases and protocols are currently being developed that allow for rapid assignment of such source parameters. In this paper, we summarize how an interdisciplinary working group on eruption source parameters has been instigating research to improve upon the current understanding of volcanic ash cloud characterization and predictions. Improved predictions of ash cloud movement and air fall will aid in making better hazard assessments for aviation and for public health and air quality. ?? 2008 Elsevier B.V.

  16. Determination of time- and height-resolved volcanic ash emissions and their use for quantitative ash dispersion modeling: the 2010 Eyjafjallajökull eruption

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Prata, A. J.; Eckhardt, S.; Clarisse, L.; Durant, A.; Henne, S.; Kristiansen, N. I.; Minikin, A.; Schumann, U.; Seibert, P.; Stebel, K.; Thomas, H. E.; Thorsteinsson, T.; Tørseth, K.; Weinzierl, B.

    2011-05-01

    The April-May, 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that large improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8-28 μm diameter. We evaluate the results of our model results with a posteriori ash emissions using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "Normal" flying zone in up to 14 % (6-16 %), 2 % (1-3 %) and 7 % (4-11 %), respectively, of the European area. For a limit of 2 mg m-3 only two episodes with fractions of 1.5 % (0.2-2.8 %) and 0.9 % (0.1-1.6 %) occurred, while the current "No-Fly" zone criterion of 4 mg m-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system.

  17. Electrical charging of volcanic ash from Eyjafjallajökull

    NASA Astrophysics Data System (ADS)

    Aplin, Karen; Nicoll, Keri; Houghton, Isobel

    2015-04-01

    Electrical charging of volcanic ash is important for both the generation of lightning and the detectability and lifetime of volcanic plumes, but remains poorly understood. Previous work showed that volcanic ash samples obtained from the 2011 Grímsvötn eruption were readily electrically charged by friction, a process known as contact charging or triboelectrification. The efficiency of charging depended on the span, or width, of the particle size distribution, with broader charge distributions charging more than narrower or more multimodal distributions. Here we report results of laboratory experiments investigating the charging of ash from Eyjafjallajökull, using samples collected from Sólheimaheithi, 22km from the crater, on 5 May 2010. A similar methodology to the earlier experiments with Grímsvötn ash was used, which involved letting small quantities of ash fall through a charge collection apparatus, and measuring the charge with a sensitive electrometer. The ash was sieved into different size bins, and artificial size distributions were also created to investigate the effect of the modality and span of the samples tested. Like the ash from Grímsvötn, the Eyjafjallajøkull ash charged more effectively when the size distribution was broader. Ash from Grímsvötn charged more readily, and with an opposite sign, than Eyjafjallajökull ash, with a median net charge of +630 pC/g compared to -116 pC/g. This difference in charging is not completely explained by the span effect described above, since the two unsieved ash samples had very similar overall spans, so would have been expected to have similar median net charges. We find that the charging may also be affected by the role of the smallest particles,

  18. Olivine + halides: a recipe for iron mobilization in volcanic ash?

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, G.; Hort, M. K.; Langmann, B.

    2013-12-01

    During the last decade, scientific evidences strongly suggest that volcanic ash iron has fertilization impact upon the surface ocean. Still, it is not well constrained how the insoluble iron in ash (i.e., as a component in minerals and also glass) could be mobilized during volcanic eruptions and atmospheric transport. Here we investigate the volcanic plume controls on ash iron solubility. We develope a conceptual box model to simulate the high, mid and low temperature chemical, physical and thermodynamic processes in eruption plumes to better constrain the iron mobilization in volcanic ash. We take into account the interaction of different species in a solid-liquid-gas system representing various volcanic settings (convergent plate, divergent plate and hot spot). Results show that the hot core of a volcanic plume (T>600°C) does not produce soluble iron directly but significantly controls the Fe mineralogy and oxidation state at the ash surface. The final iron mineralogy at the ash surface (i.e. the ash's oxidation front with 1-100 nm thickness) is likely to be independent of temperature and oxygen fugacity and is closely correlated to the ratio of H2 and H2S content of the magmatic gas to the amount of entrained oxygen. As the plume continues rising and cooling, sulfuric acid condenses at about 150°C followed by water condensation at about 50°C which also dissociates sulfuric acid and produces H+ ions in the liquid phase. The aqueous phase scavenges the surrounding gas species (e.g. SO2, HCl, HF) and concurrently dissolves the ash surface constituents. Since HCl is about 4 orders of magnitudes more soluble than SO2, its dissolution mainly controls the pH of the liquid. Hence, high HCl concentrations in the gas phase results in lower pH in the aqueous phase (pH<0.5) and consequently an increase in the ash dissolution rate. Moreover reduced iron carrying minerals (e.g. fayalite) show a much higher dissolution rate in comparison with oxidized species (e.g. hematite

  19. Volcanic ash: What it is and how it forms

    SciTech Connect

    Heiken, G.

    1991-09-13

    There are four basic eruption processes that produce volcanic ash: (1) decompression of rising magma, gas bubble growth, and fragmentation of the foamy magma in the volcanic vent (magmatic), (2) explosive mixing of magma with ground or surface water (hydrovolcanic), (3) fragmentation of country rock during rapid expansion of steam and/or hot water (phreatic), and (4) breakup of lava fragments during rapid transport from the vent. Variations in eruption style and the characteristics of volcanic ashes produced during explosive eruptions depend on many factors, including magmatic temperature, gas content, viscosity and crystal content of the magma before eruption, the ratio of magma to ground or surface water, and physical properties of the rock enclosing the vent. Volcanic ash is composed of rock and mineral fragments, and glass shards, which is less than 2 mm in diameter. Glass shard shapes and sizes depend upon size and shape of gas bubbles present within the magma immediately before eruption and the processes responsible for fragmentation of the magma. Shards range from slightly curved, thin glass plates, which were broken from large, thin-walled spherical bubble walls, to hollow needles broken from pumiceous melts containing gas bubbles stretched by magma flow within the volcanic vent. Pumice fragments make up the coarser-grained portions of the glass fraction. Particle sizes range from meters for large blocks expelled near the volcanic vent to nanometers for fine ash and aerosol droplets within well-dispersed eruption plumes. 18 refs., 6 figs., 1 tab.

  20. Volcanic ash forecast transport and dispersion (VAFTAD) model

    SciTech Connect

    Heffter, J.L.; Stunder, B.J.B.

    1993-12-01

    The National Oceanic and Atmospheric Administration (NOAA) Air Resources Laboratory (ARL) has developed a Volcanic Ash Forecast Transport And Dispersion (VAFTAD) model for emergency response use focusing on hazards to aircraft flight operations. The model is run on a workstation at ARL. Meteorological input for the model is automatically downloaded from the NOAA National Meteorological Center (NMC) twice-daily forecast model runs to ARL. Additional input for VAFTAD ragarding the volcanic eruption is supplied by the user guided by monitor prompts. The model calculates transport and dispersion of volcanic ash from an initial ash cloud that has reached its maximum height within 3 h of eruption time. The model assumes that spherical ash particles of diameters ranging from 0.3 to 30 micrometers are distributed throughout the initial cloud with a particle number distribution based on Mount St. Helens and Redoubt Volcano eruptions. Particles are advected horizontally and vertically by the winds and fall according to Stoke`s law with a slip correction. A bivariate-normal distribution is used for horizontally diffusing the cloud and determining ash concentrations. Model output gives maps with symbols representing relative concentrations in three flight layers, and throughout the entire ash cloud, for sequential 6- and 12-h time intervals. A verification program for VAFTAD has been started. Results subjectively comparing model ash cloud forecasts with satellite imagery for three separate 1992 eruptions of Mount Spurr in Alaska have been most encouraging.

  1. Unmanned Airborne Platforms for Validation of Volcanic Emission Composition and Transport Models

    NASA Astrophysics Data System (ADS)

    Pieri, D. C.; Diaz, J. A.; Bland, G.; Fladeland, M. M.

    2012-12-01

    In recent years there has been an increasing realization that current remote sensing retrieval and transport models to detect, characterize, and track airborne volcanic emissions will be much improved fundamentally, and in their application, by the acquisition of in situ validation data. This issue was highlighted by the need for operational estimates of airborne ash concentrations during the 2010 eruption at Eyjafjallajökull-Fimmvörduháls in Iceland. In response, important campaigns were mounted in Europe to conduct airborne in situ observations with manned aircraft to validate ash concentration estimates based on remote sensing data. This effort had immediate application providing crucial accuracy and precision estimates for predicting locations, trajectories, and concentrations of the drifting ash to mitigate the severe economic impacts caused by the continent-wide grounding of aircraft. Manned flying laboratories, however, sustain serious risks if flown into the areas of volcanic plumes and drifting clouds that are of the highest interest, namely the zones of most concentrated ash and gas, which are often opaque to upwelling radiation at the longer infrared wavelengths (e.g., 8-12μm), where ash and gas can be most readily detected. Unmanned airborne vehicles (UAVs), of course, can provide volcanic aerosol and gas sampling and measurement platforms with no risk to flight crews, and can penetrate the most ash-concentrated zones of plumes and drifting clouds. Current interest has been high in developing and testing small UAVs (e.g., NASA, University of Costa Rica, University of Düsseldorf; INGV-Catania and Rome, and others) for proximal sulfur dioxide and solid aerosol observations and sampling in relatively quiescently erupting plumes as a first step toward more far ranging and higher altitude deployments into drifting volcanic ash clouds at regional scales. Nevertheless, in the aftermath of the Icelandic crisis, ash and gas concentrations from analysis of

  2. Deposition Rate and Size Distribution of Volcanic Ash

    NASA Astrophysics Data System (ADS)

    Hikida, M.

    2006-12-01

    Sakurajima Volcano has been in violent activity since 1955 and erupting large amount of volcanic ash and stones from the crater. Volcanic fallouts have caused damages to the agricaltural products in the area and denuded the mountainside of vegitation. Deposited ash and stones on the mountainside has also caused hazardrous debris flows in the rivers. Therefore, it is necessary to know the deposition rate of the fallouts in prediction of debris flow. Due to the violent volcanic activity, however, it is prohibited to enter within two kilometers of the crater, making it impossible to measure the depth of deposited fallouts in the area. Theoretical study on deposition rate of volcanic fallouts should be needed to estimate the amount of fallouts in the upstream area. At first, motion of a particle erupted from the crater into the air was computed to examine its trajectory. From the simulation of the trajectory, a particle was assumed to fall at its terminal veloctity, and theoretical equation which give the deposition rate of volcanic ash and the distribution of deposited ash were obtained. In the derivation of these equations, the probability density functions of eruption column height, the terminal velocity of the erupted particles and the wind velocity were introduced. The computed values of amount of deposited ash show good agreement with the data taken from 93 collection points around Sakurajima Volcano. The annual amount of erupted volcanic ash was estimated to be about thirteen millions tons. The sample of deposited fallouts were taken to analize the size distribution. The data was also used to check the applicability of the theory presented.

  3. Experimental aggregation of volcanic ash: the role of liquid bonding

    NASA Astrophysics Data System (ADS)

    Mueller, S.; Kueppers, U.; Jacob, M.; Ayris, P. M.; Dingwell, D. B.

    2015-12-01

    Explosive volcanic eruptions may release vast quantities of ash. Because of its size, it has the greatest dispersal potential and can be distributed globally. Ash may pose severe risks for 1) air traffic, 2) human and animal health, 3) agriculture and 4) infrastructure. Such ash particles can however cluster and form ash aggregates that range in size from millimeters to centimeters. During their growth, weight and aerodynamic properties change. This leads to significantly changed transport and settling behavior. The physico-chemical processes involved in aggregation are quantitatively poorly constrained. We have performed laboratory ash aggregation experiments using the ProCell Lab System® of Glatt Ingenieurtechnik GmbH. Solid particles are set into motion in a fluidized bed over a range of well-controlled boundary conditions (e.g., air flow rate, gas temperature, humidity, liquid composition). In this manner we simulate the variable gas-particle flow conditions expected in eruption plumes and pyroclastic density currents. We have used 1) soda-lime glass beads as an analogue material and 2) natural volcanic ash from Laacher See Volcano (Germany). In order to influence form, size, stability and the production rate of aggregates, a range of experimental conditions (e.g., particle concentration, degree of turbulence, temperature and moisture in the process chamber and the composition of the liquid phase) have been employed. We have successfully reproduced several features of natural ash aggregates, including round, internally structured ash pellets up to 3 mm in diameter. These experimental results help to constrain the boundary conditions required for the generation of spherical, internally-structured ash aggregates that survive deposition and are preserved in the volcanological record. These results should also serve as input parameters for models of ash transport and ash mass distribution.

  4. An accelerated data assimilation approach for volcanic ash forecast

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Lin, Haixiang; Heemink, Arnold; Segers, Arjo; Lu, Sha

    2016-04-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash forecast in recent years. Ensemble-based data assimilation uses the observation data to improve the parameter and state estimation and subsequently the volcanic ash forecast accuracy. Due to the computational complexity of ensemble-based algorithms and the large scale of real-life applications, application of these methods usually introduces a large computational cost, particularly in the analysis step of assimilation processes. Because the other time-consuming part in the single CPU case, the forecast step, can be efficiently and easily parallelized. In this study, we focus on speeding up of the analysis step. For volcanic ash assimilation of aircraft-based measurements, the most time-consuming part in the analysis step has been shown to be the computation of the Kalman gain matrix. After a careful study on the characteristics of ensemble ash states, we propose a model-reduced Kalman gain (MR-Gain) approach which transforms the ensemble state matrix into a low-rank matrix by a multiplication with an index matrix which recorded the sparsity information of the ensemble state matrix, and thus the computational cost of all the ensemble-related matrix multiplications are reduced. After the computation of Kalman gain, using the previously recorded state index, the full analyzed ensemble states are reconstructed. The result shows the MR-Gain approach is exact, which can be used to replace the original full matrix with a much low computation cost. Computer experiments show that the computing time for the analysis step with the new approach is a factor of ten times faster than the conventional analysis step. The result also shows that with the accelerated analysis step in volcanic ash assimilation system, the total amount of computing time for volcanic ash forecast can be significantly reduced by up to a factor of 5.

  5. Toward an Integrated Solution to Mitigate the Impact of Volcanic Ash to Aviation

    NASA Technical Reports Server (NTRS)

    Murray, John J.; Dezitter, Fabien; Fairlie, T. Duncan; Krotkov, Nickolay; Lekki, John; Lindsay, Francis; Pavolonis, Mike; Pieri, David; Prata, Fred; Vernier, Jean-Paul

    2015-01-01

    The science community is making a concerted effort to improve the reliability of dispersion models for the forecasting of volcanic ash plumes. Toward this end, it has been observed that the assimilation of diverse, accurate and frequent surface, airborne and satellite observations of the source and distal ash plumes may hold the key. Various international research organizations and operational agencies make these observations using a variety of active and passive remote sensing systems and use them to initialize atmospheric trajectory and dispersion models. These observation systems range from surface LIDAR and ceilometers, to airborne radiometers and nephelometers, to satellite radiometers, multi-spectral imagers, LIDAR and UV-photometers. None of these systems alone is a panacea, however, their synergistic application holds great promise toward solving this complex problem. Additionally, the aeronautical and science communities are working to better understand the quantitative thresholds and tolerances of aviation systems to volcanic ash to better inform scientists of the accuracy requirements for dispersion model forecasts. A number of the most recent and promising efforts in all of these area are discussed in this presentation.

  6. The United States national volcanic ash operations plan for aviation

    USGS Publications Warehouse

    Albersheim, Steven; Guffanti, Marianne

    2009-01-01

    Volcanic-ash clouds are a known hazard to aviation, requiring that aircraft be warned away from ash-contaminated airspace. The exposure of aviation to potential hazards from volcanoes in the United States is significant. In support of existing interagency operations to detect and track volcanic-ash clouds, the United States has prepared a National Volcanic Ash Operations Plan for Aviation to strengthen the warning process in its airspace. The US National Plan documents the responsibilities, communication protocols, and prescribed hazard messages of the Federal Aviation Administration, National Oceanic and Atmospheric Administration, US Geological Survey, and Air Force Weather Agency. The plan introduces a new message format, a Volcano Observatory Notice for Aviation, to provide clear, concise information about volcanic activity, including precursory unrest, to air-traffic controllers (for use in Notices to Airmen) and other aviation users. The plan is online at http://www.ofcm.gov/p35-nvaopa/pdf/FCM-P35-2007-NVAOPA.pdf. While the plan provides general operational practices, it remains the responsibility of the federal agencies involved to implement the described procedures through orders, directives, etc. Since the plan mirrors global guidelines of the International Civil Aviation Organization, it also provides an example that could be adapted by other countries.

  7. Dispersed Ash in Marine Sediment: An Overview Towards Unraveling the 'Missing Volcanic Record'

    NASA Astrophysics Data System (ADS)

    Murray, R. W.; Scudder, R.; Kutterolf, S.; Schindlbeck, J.

    2013-12-01

    Volcanic ash occurs in marine sediment both as discrete layers as well as isolated grains and shards dispersed throughout the bulk sediment, and with highly variable grain sizes. The study of this dispersed component has lagged behind the sophisticated petrographic, sedimentologic, geochemical, and isotopic assessment of the ash layer record. For example, while decades of smear-slide studies of bulk sediment in volcanic-rich regimes have presented visual estimations of the abundance of 'volcanic glass', 'shards', and/or other components, the quantitative importance of the dispersed ash and/or the cryptotephra component remains largely unconstrained on local, regional, and global scales. Chemical and isotopic characterization of this dispersed component has remained elusive. Building on earlier work, research in the 1970s began documenting the importance of dispersed ash and its alteration products. This dispersed ash is the result of the bioturbation of pre-existing discrete layers, the settling of airborne ash, distribution from subaqueous eruptions, and other mechanisms. Compared to the often visually stunning ash layer records, which in certain settings can leave single layers with thicknesses of 10s of cm, the dispersed ash component and cryptotephra layers are unable to be visually differentiated from detrital clay. Furthermore, its extremely fine grain size is an additional hindrance to quantification of its abundance and the identification of source. More completely characterizing the total ash inventory (that is, the dispersed ash in addition to the ash layers) will contribute significantly to studies of marine and terrestrial volcanism at many scales, geochemical mass balances, arc evolution, hydration of marine sediment during alteration, atmospheric circulation, putative relationships between volcanism and climate, and other key components of the earth-ocean-atmosphere system. Beginning with work in the Caribbean Sea and progressing to the northwest

  8. A new natural hazards data-base for volcanic ash and SO2 from global satellite remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Stebel, Kerstin; Prata, Fred; Theys, Nicolas; Tampellini, Lucia; Kamstra, Martijn; Zehner, Claus

    2014-05-01

    used in VAST to simulate the dispersion of volcanic ash and SO2 emitted during an eruption. Source terms and dispersion model results will be given. In time, data from conventional in situ sampling instruments, airborne and ground-based remote sensing platforms and other meta-data (bulk ash and gas properties, volcanic setting, volcanic eruption chronologies, potential impacts etc.) will be added. Important applications of the data-base are illustrated related to the ash/aviation problem and to estimating SO2 fluxes from active volcanoes-as a means to diagnose future unrest. The data-base has the potential to provide the natural hazards community with a dynamic atmospheric volcanic hazards map and will be a valuable tool particularly for aviation.

  9. Dating volcanic ash by use of thermoluminescence

    SciTech Connect

    Berger, G.W. )

    1992-01-01

    The fine-silt-sized (4-11 {mu}m) grains of glass separated from four samples of independently dated, 8 to 400 ka, tephra beds provide accurate thermoluminescence (TL) ages. This demonstration of reliable TL dating of volcanic glass provides a new tephrochronometer for deposits spanning the Holocene to middle Pleistocene age range.

  10. Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards

    NASA Astrophysics Data System (ADS)

    Ham, H. J.; Lee, S.; Choi, S. H.; Yun, W. S.

    2015-12-01

    Agricultural Fragility Estimates Subjected to Volcanic Ash Fall Hazards Hee Jung Ham1, Seung-Hun Choi1, Woo-Seok Yun1, Sungsu Lee2 1Department of Architectural Engineering, Kangwon National University, Korea 2Division of Civil Engineering, Chungbuk National University, Korea ABSTRACT In this study, fragility functions are developed to estimate expected volcanic ash damages of the agricultural sector in Korea. The fragility functions are derived from two approaches: 1) empirical approach based on field observations of impacts to agriculture from the 2006 eruption of Merapi volcano in Indonesia and 2) the FOSM (first-order second-moment) analytical approach based on distribution and thickness of volcanic ash observed from the 1980 eruption of Mt. Saint Helens and agricultural facility specifications in Korea. Fragility function to each agricultural commodity class is presented by a cumulative distribution function of the generalized extreme value distribution. Different functions are developed to estimate production losses from outdoor and greenhouse farming. Seasonal climate influences vulnerability of each agricultural crop and is found to be a crucial component in determining fragility of agricultural commodities to an ash fall. In the study, the seasonality coefficient is established as a multiplier of fragility function to consider the seasonal vulnerability. Yields of the different agricultural commodities are obtained from Korean Statistical Information Service to create a baseline for future agricultural volcanic loss estimation. Numerically simulated examples of scenario ash fall events at Mt. Baekdu volcano are utilized to illustrate the application of the developed fragility functions. Acknowledgements This research was supported by a grant 'Development of Advanced Volcanic Disaster Response System considering Potential Volcanic Risk around Korea' [MPSS-NH-2015-81] from the Natural Hazard Mitigation Research Group, Ministry of Public Safety and Security of

  11. Spatial evaluation of volcanic ash forecasts using satellite observations

    NASA Astrophysics Data System (ADS)

    Harvey, N. J.; Dacre, H. F.

    2015-09-01

    The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper an objective metric to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash is presented. The metric is based on the fractions skill score (FSS). This measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealised scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200-700 km2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite retrieved ash data and evaluate VATD forecasts over a long time period.

  12. Spatial evaluation of volcanic ash forecasts using satellite observations

    NASA Astrophysics Data System (ADS)

    Harvey, N. J.; Dacre, H. F.

    2016-01-01

    The decision to close airspace in the event of a volcanic eruption is based on hazard maps of predicted ash extent. These are produced using output from volcanic ash transport and dispersion (VATD) models. In this paper the fractions skill score has been used for the first time to evaluate the spatial accuracy of VATD simulations relative to satellite retrievals of volcanic ash. This objective measure of skill provides more information than traditional point-by-point metrics, such as success index and Pearson correlation coefficient, as it takes into the account spatial scale over which skill is being assessed. The FSS determines the scale over which a simulation has skill and can differentiate between a "near miss" and a forecast that is badly misplaced. The idealized scenarios presented show that even simulations with considerable displacement errors have useful skill when evaluated over neighbourhood scales of 200-700 (km)2. This method could be used to compare forecasts produced by different VATDs or using different model parameters, assess the impact of assimilating satellite-retrieved ash data and evaluate VATD forecasts over a long time period.

  13. Volcanic ash transport integrated in the WRF-Chem model: a description of the application and verification results from the 2010 Eyjafjallajökull eruption.

    NASA Astrophysics Data System (ADS)

    Stuefer, Martin; Webley, Peter; Grell, Georg; Freitas, Saulo; Kim, Chang Ki; Egan, Sean

    2013-04-01

    Regional volcanic ash dispersion models are usually offline decoupled from the numerical weather prediction model. Here we describe a new functionality using an integrated modeling system that allows simulating emission, transport, and sedimentation of pollutants released during volcanic activities. A volcanic preprocessor tool has been developed to initialize the Weather Research Forecasting model with coupled Chemistry (WRF-Chem) with volcanic ash and sulphur dioxide emissions. Volcanic ash variables were added into WRF-Chem, and the model was applied to study the 2010 eruption of Eyjafjallajökull. We evaluate our results using WRF-Chem with available ash detection data from satellite and airborne sensors, and from ground based Lidar measurements made available through the AeroCom project. The volcanic ash was distributed into 10 different bins according to the particle size ranging from 2 mm to less than 3.9 μm; different particle size distributions derived from historic eruptions were tested. An umbrella shaped initial ash cloud and an empirical relationship between mass eruption rates and eruption heights were used to initialize WRF-Chem. We show WRF-Chem model verification for the Eyjafjallajökull eruptions, which occurred during the months of April and May 2010. The volcanic ash plume dispersed extensively over Europe. Comparisons with satellite remote sensing volcanic ash retrievals showed good agreement during the events, also ground-based LIDAR compared well to the model simulations. The model sensitivity analysis of the Eyjafjallajökull event showed a considerable bias of ass mass concentrations afar from the volcano depending on initial ash size and eruption rate assumptions. However the WRF-Chem model initialized with reliable eruption source parameters produced good quality forecasts, and will be tested for operational volcanic ash transport predictions.

  14. Towards probabilistic forecasts of volcanic ash transport in the atmosphere

    NASA Astrophysics Data System (ADS)

    Zidikheri, M. J.; Dare, R.; Potts, R.; Lucas, C.

    2015-12-01

    Satellite based remote sensing techniques are the primary means of identifying the location of volcanic ash during eruption events. This information is then used to initialize ash dispersion models, which employ meteorological fields to forecast the future locations of ash. Remote sensing of ash in tropical regions is especially challenging due to the difficulty of demarcating ash from the ice and water in convective clouds which results in frequent missed and false detections of ash. Dispersion models also contain uncertainties that arise from uncertainties in the meteorological fields and the source term such the height of the ash column. Communicating forecasting uncertainties is becoming increasingly important to stakeholders for the purposes of improved risk management. For these reasons the Bureau of Meteorology is engaged in research with the aim of providing probabilistic forecasts of ash in the near future based on ensembles of dispersion model simulations. The ensembles are constructed to reflect two fundamental uncertainties. Firstly, uncertainties in the meteorological fields are incorporated by the use of the Bureau's ensemble model system which issues a set of 24 meteorological forecasts representing possible states of the atmosphere. Secondly, uncertainties in the model parameters such as the ash column height are also incorporated. This is accomplished by running a suite of dispersion model simulations, each with a different value of the model parameter. Pattern correlations are then used to quantify the match between the model and observations. The model parameters which provide the best matches between model and observations are then employed in the ensemble to issue probabilistic forecasts of ash. This process can also ameliorate errors due to incorrect or missing model physics. The efficacy of these techniques shall be demonstrated by the use of several case studies.

  15. Airborne stratospheric observations of major volcanic eruptions: past and future

    NASA Astrophysics Data System (ADS)

    Newman, P. A.; Aquila, V.; Colarco, P. R.

    2015-12-01

    Major volcanic eruptions (e.g. the 1991 eruption of Mt. Pinatubo) lead to a surface cooling and disruptions of the chemistry of the stratosphere. In this presentation, we will show model simulations of Mt. Pinatubo that can be used to devise a strategy for answering specific science questions. In particular, what is the initial mass injection, how is the cloud spreading, how are the stratospheric aerosols evolving, what is the impact on stratospheric chemistry, and how will climate be affected? We will also review previous stratospheric airborne observations of volcanic clouds using NASA sub-orbital assets, and discuss our present capabilities to observe the evolution of a stratospheric volcanic plume. These capabilities include aircraft such as the NASA ER-2, WB-57f, and Global Hawk. In addition, the NASA DC-8 and P-3 can be used to perform remote sensing. Balloon assets have also been employed, and new instrumentation is now available for volcanic work.

  16. A method for characterizing volcanic ash

    SciTech Connect

    Bayhurst, G.K.; Wohletz, K.H.; Mason, A.S.

    1991-01-01

    The development of an automated program for characterization of particles using a scanning electron microscope (SEM) with an energy dispersive X-ray detector (EDS) has greatly reduced the time required for analysis of particulate samples. The SEM system provides a digital representation of all particles scanned such that further measurement of the size, shape, and area are a product of image processing. The EDS and associated software provides information as to the particles' chemical composition. The data obtained from the SEM by this method are reduced by computer to obtain distribution graphs for size, density, shape, and mineralogy. These SEM results have been tested by comparisons with results obtained by traditional optical microscopy, which supports the results and provide details concerning crystallinity and glass content. This method was applied to the ash that damaged the engines from the KLM 747 flight of December 15, 1989 while encountering the ash cloud from Redoubt Volcano. The sample was collected from the pitot-static system and had not been exposed to any engine parts that might have changed its characteristics. The sample analysis presented here demonstrates the capabilities and information obtainable from out automated SEM technique. 5 refs., 7 figs., 3 tabs.

  17. Using stochastic NWP ensembles for volcanic ash transport and dispersion model outcomes

    NASA Astrophysics Data System (ADS)

    Patra, A. K.; Bursik, M. I.; Stefanescu, E.; Pitman, E.; Singh, T.; Singla, P.

    2012-12-01

    Ash clouds ejected into the atmosphere by volcanic eruption extend over large areas and can travel thousands of kilometers from the source volcano, disrupting air traffic and posing a significant hazard to air travel. Volcanic ash transport and dispersion models like the PUFF model simulate the ash transport and dispersion. An important input parameter for such simulations are wind fields. They represent one of the major sources for uncertainties in ash transport and dispersion simulations. Ensemble methods are considered to be an effective way to estimate the probability density function of future states of the atmosphere by addressing uncertainties present in initial conditions and in model approximations. To generate localized wind ensemble we are using the Weather Research and Forecast (WRF) model with various initial conditions. We examine the spatial variability of the wind fields as well as their uncertainty by using two methods to simulate uncertainty on initial conditions. First method was developed by National Centers for Environmental Prediction (NCEP) and it is based on breeding vectors [2], while the second method was proposed by [1] and uses a distribution of the initial conditions to describe the confidence in the knowledge of the initial state of the atmosphere. PUFF runs are performed with the above wind fields for the eruption of Eyjafjallajokull, Iceland which had a peak ash emission in the period 15-20 April 2010.. A variety of model outputs are compiled, including snapshots of airborne-ash concentration (relative to the number of particles released at the start of the simulation) and particle location color-coded by height which shows the sensitivity of these outputs to wind fields. [1] E. Constantinescu, V. Zavala, M. Rocklin, S. Lee, and M. Anitescu. A com- putational framework for uncertainty quantification and stochastic optimiza- tion in unit commitment with wind power generation. IEEE Transactions on Power Systems, 2010. [2] Z. Toth and E

  18. Experimentally constraining the boundary conditions for volcanic ash aggregation

    NASA Astrophysics Data System (ADS)

    Kueppers, U.; Auer, B.; Cimarelli, C.; Scolamacchia, T.; Guenthel, M.; Dingwell, D. B.

    2011-12-01

    Volcanic ash is the primary product of various volcanic processes. Due to its size, ash can remain in the atmosphere for a prolonged period of time. Aggregation processes are a first-order influence on the residence time of ash in the atmosphere and its dispersion from the vent. Due to their internal structure, ash aggregates have been classified as ash pellets or accretionary lapilli. Although several concomitant factors may play a role during aggregation, there is a broad consensus that both 1) particle collision and 2) humidity are required for particles to aggregate. However, direct observation of settling aggregates and record of the boundary conditions favourable to their formation are rare, therefore limiting our understanding of the key processes that determine ash aggregates formation. Here, we present the first results from experiments aimed at reproducing ash aggregation by constraining the required boundary conditions. We used a ProCell Lab System of Glatt Ingenieurtechnik GmbH that is conventionally used for food and chemical applications. We varied the following parameters: 1) air flow speed [40-120 m3/h], 2) air temperature [30-60°C], 3) relative humidity [20-50 %], and 4) liquid droplets composition [water and 25% water glass, Na2SiO3]. The starting material (125-90 μm) is obtained by milling natural basaltic lapilli (Etna, Italy). We found that the experimental duration and the chosen conditions were not favourable for the production of stable aggregates when using water as spraying liquid. Using a 25% water-glass solution as binder we could successfully generate and investigate aggregates of up to 2 mm size. Many aggregates are spherical and resemble ash pellets. In nature, ash pellets and accretionary lapilli are the product of complex processes taking place at very different conditions (temperature, humidity, ash concentration, degree of turbulence). These experiments shed some first light on the ash agglomeration process for which direct

  19. WSR-88D observations of volcanic ash

    USGS Publications Warehouse

    Wood, J.; Scott, C.; Schneider, D.

    2007-01-01

    Conclusions that may impact operations are summarized below: ??? Current VCPs may not be optimal for the scharacterization of volcanic events. Therefore, the development of a new VCP that combines the enhanced low level elevation density and increased temporal resolution of VCP 12 with the enhanced sensitivity of VCP 31. ??? Given currently available scan strategies, this preliminary investigation would suggest that it is advisable to use VCP 12 during the initial explosive phase of an eruptive event. Once the maximum reflectivity has dropped below 30 dBZ, VCP 31 should be used. ??? This study clearly indicates that WSR-88D Level II data offers many advantages over Level III data currently available in Alaska. The ability to access this data would open up greater opportunities for research. Given the proximity of WSR-88D platforms to active volcanoes in Alaska, as well as in the western Lower 48 states and Hawaii, radar data will likely play a major operational role when volcanic eruptions again pose a threat to life and property. The utilization of this tool to its maximum capability is vital.

  20. Using Volcanic Ash to Remove Dissolved Uranium and Lead

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Cuero, Raul G.

    2009-01-01

    Experiments have shown that significant fractions of uranium, lead, and possibly other toxic and/or radioactive substances can be removed from an aqueous solution by simply exposing the solution, at ambient temperature, to a treatment medium that includes weathered volcanic ash from Pu'u Nene, which is a cinder cone on the Island of Hawaii. Heretofore, this specific volcanic ash has been used for an entirely different purpose: simulating the spectral properties of Martian soil. The treatment medium can consist of the volcanic ash alone or in combination with chitosan, which is a natural polymer that can be produced from seafood waste or easily extracted from fungi, some bacteria, and some algae. The medium is harmless to plants and animals and, because of the abundance and natural origin of its ingredient( s), is inexpensive. The medium can be used in a variety of ways and settings: it can be incorporated into water-filtration systems; placed in contact or mixed with water-containing solids (e.g., soils and sludges); immersed in bodies of water (e.g., reservoirs, lakes, rivers, or wells); or placed in and around nuclear power plants, mines, and farm fields.

  1. Disposal of domestic sludge and sludge ash on volcanic soils.

    PubMed

    Escudey, Mauricio; Förster, Juan E; Becerra, Juan P; Quinteros, Magdalena; Torres, Justo; Arancibia, Nicolas; Galindo, Gerardo; Chang, Andrew C

    2007-01-31

    Column leaching experiments were conducted to test the ability of Chilean volcanic soils in retaining the mineral constituents and metals in sewage sludge and sludge ash that were incorporated into the soils. Small or negligible amounts of the total content of Pb, Fe, Cr, Mn, Cd, and Zn (0 to <2%), and more significant amounts of mineral constituents such as Na (7-9%), Ca (7-13%), PO4 (4-10%), and SO4 (39-46%) in the sludge and sludge ash were readily soluble. When they were incorporated on the surface layer of the soils and leached with 12 pore volumes of water over a 3 month period of time, less than 0.1% of the total amount of heavy metals and PO4 in the sludge and sludge ash were collected in the drainage water. Cation exchange selectivity, specific anion adsorption and solubility are the processes that cause the reduction of leaching. The volcanic soils were capable of retaining the mineral constituents, P, and metals in applied sewage sludge and sludge ash and gradually released them as nutrients for plant growth.

  2. Magmatic and fragmentation controls on volcanic ash surface chemistry

    NASA Astrophysics Data System (ADS)

    Ayris, Paul M.; Diplas, Spyros; Damby, David E.; Hornby, Adrian J.; Cimarelli, Corrado; Delmelle, Pierre; Scheu, Bettina; Dingwell, Donald B.

    2016-04-01

    The chemical effects of silicate ash ejected by explosive volcanic eruptions on environmental systems are fundamentally mediated by ash particle surfaces. Ash surfaces are a composite product of magmatic properties and fragmentation mechanisms, as well as in-plume and atmospheric alteration processes acting upon those surfaces during and after the eruption. Recent attention has focused on the capacity of alteration processes to shape ash surfaces; most notably, several studies have utilised X-ray photoelectron spectroscopy (XPS), a technique probing the elemental composition and coordination state of atoms within the top 10 nm of ash surfaces, to identify patterns of elemental depletions and enrichments relative to bulk ash chemical composition. Under the presumption of surface and bulk equivalence, any disparities have been previously attributed to surface alteration processes, but the ubiquity of some depletions (e.g., Ca, Fe) across multiple ash studies, irrespective of eruptive origin, could suggest these to be features of the surface produced at the instant of magma fragmentation. To investigate this possibility further, we conducted rapid decompression experiments at different pressure conditions and at ambient and magmatic temperature on porous andesitic rocks. These experiments produced fragmented ash material untouched by secondary alteration, which were compared to particles produced by crushing of large clasts from the same experiments. We investigated a restricted size fraction (63-90 μm) from both fragmented and crushed materials, determining bulk chemistry and mineralogy via XRF, SEM-BSE and EPMA, and investigated the chemical composition of the ash surface by XPS. Analyses suggest that fragmentation under experimental conditions partitioned a greater fraction of plagioclase-rich particles into the selected size fraction, relative to particles produced by crushing. Trends in surface chemical composition in fragmented and crushed particles mirror that

  3. Deposition and immersion-mode nucleation of ice by three distinct samples of volcanic ash

    NASA Astrophysics Data System (ADS)

    Schill, G. P.; Genareau, K.; Tolbert, M. A.

    2015-07-01

    Ice nucleation of volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui eruption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225 to 235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited appreciable heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

  4. Determination of time- and height-resolved volcanic ash emissions for quantitative ash dispersion modeling: the 2010 Eyjafjallajökull eruption

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Prata, A. J.; Eckhardt, S.; Clarisse, L.; Durant, A.; Henne, S.; Kristiansen, N. I.; Minikin, A.; Schumann, U.; Seibert, P.; Stebel, K.; Thomas, H. E.; Thorsteinsson, T.; Tørseth, K.; Weinzierl, B.

    2011-02-01

    The April-May 2010 volcanic eruptions of Eyjafjallajökull, Iceland caused significant economic and social disruption in Europe whilst state of the art measurements and ash dispersion forecasts were heavily criticized by the aviation industry. Here we demonstrate for the first time that dramatic improvements can be made in quantitative predictions of the fate of volcanic ash emissions, by using an inversion scheme that couples a priori source information and the output of a Lagrangian dispersion model with satellite data to estimate the volcanic ash source strength as a function of altitude and time. From the inversion, we obtain a total fine ash emission of the eruption of 8.3 ± 4.2 Tg for particles in the size range of 2.8-28 μm diameter and extrapolate this to a total ash emission of 11.9 ± 5.9 Tg for the size range of 0.25-250 μm. We evaluate the results of our a posteriori model using independent ground-based, airborne and space-borne measurements both in case studies and statistically. Subsequently, we estimate the area over Europe affected by volcanic ash above certain concentration thresholds relevant for the aviation industry. We find that during three episodes in April and May, volcanic ash concentrations at some altitude in the atmosphere exceeded the limits for the "normal" flying zone in up to 14% (6-16%), 2% (1-3%) and 7% (4-11%), respectively, of the European area. For a limit of 2 mg m-3 only two episodes with fractions of 1.5% (0.2-2.8%) and 0.9% (0.1-1.6%) occurred, while the current "no-fly" zone criterion of 4 mg m-3 was rarely exceeded. Our results have important ramifications for determining air space closures and for real-time quantitative estimations of ash concentrations. Furthermore, the general nature of our method yields better constraints on the distribution and fate of volcanic ash in the Earth system.

  5. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang

    2016-07-01

    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  6. The health hazards of volcanic ash--A guide for the public

    USGS Publications Warehouse

    Horwell, C.; Baxter, P.

    2007-01-01

    This document has been prepared by the International Volcanic Health Hazard Network (IVHHN), Cities and Volcanoes Commission, GNS Science and the United States Geological Survey (USGS) to promote the safety of those who experience volcanic ashfall. This guide explains the potential health effects of volcanic ash and gives details on how to protect yourself and your family in the event of a volcanic ashfall.

  7. Observing volcanic ash plumes and ballistics using Doppler radar

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-01-01

    When volcanoes erupt, they often emit coarse rocks with ballistic trajectories that fall onto the slopes of the volcano, as well as a plume of fine ash that drifts into the atmosphere. It can be challenging to monitor both simultaneously and discriminate between the two to collect quantitative data, but Valade and Donnadieu have done that with a ground-based Doppler radar, which they used to make measurements of smallscale eruptions at Arenal volcano in Costa Rica. They were able to estimate the mass of the ballistic rocks and the mass of ash particles ejected into the atmosphere. Such studies could be useful for understanding and mitigating the hazards associated with volcanic eruptions. (Geophysical Research Letters, doi:10.1029/2011GL049415, 2011)

  8. Ash mists and brown snow: Remobilization of volcanic ash from recent Icelandic eruptions

    NASA Astrophysics Data System (ADS)

    Liu, E. J.; Cashman, K. V.; Beckett, F. M.; Witham, C. S.; Leadbetter, S. J.; Hort, M. C.; Gudmundsson, S.

    2014-08-01

    Recent eruptions in Iceland and Chile have demonstrated that volcanic ash problems persist long after an eruption. For this reason, ash dispersion models are being extended to include ash remobilization. Critical to these models is knowledge of the ash source and the particle sizes that can be mobilized under different wind and moisture conditions. Here we characterize the physical and chemical characteristics of ash deposited on new snow in Reykjavík, Iceland, following a blizzard on 6 March 2013. Morphological, textural, and compositional analyses indicate resuspension from multiple eruptive deposits, including both Grímsvötn (2011) and Eyjafjallajökull (2010) eruptions. Grain size measurements show a mode of 32-63 µm, with particles as large as 177 µm; there is little mass in the very fine fraction, ≤10 µm (PM10). We compare our observations to predictions using the Lagrangian particle dispersion model, NAME (UK Met Office). The model output is consistent with observations in that it forecasts resuspension from both Eyjafjallajökull and Grímsvötn source regions, and shows ash deposition coincident with the timing of observed deposition in Reykjavík. The modeled deposit in Reykjavík predicts, however, a substantially lower proportion of Grímsvötn ash than observed. This discrepancy has highlighted the need to reassess the assumptions used in the simulations, particularly regarding the source area and precipitation thresholds. Furthermore, we suggest that modification of ash deposits in the form of erosion, redeposition, compaction, or cementation may influence the dynamics of resuspension over time, thus influencing the ability of model simulations to accurately forecast remobilization events.

  9. Spreading dynamic of viscous volcanic ash in stimulated jet engine conditions

    NASA Astrophysics Data System (ADS)

    song, wenjia; Lavallée, Yan; Hess, Kai-Uwe; Kueppers, Ulrich; Cimarelli, Corrado

    2016-04-01

    The ingestion of volcanic ash is widely recognised as a potentially fatal hazard for aircraft operation. The volcanic ash deposition process in a jet turbine is potentially complex. Volcanic ash in the air stream enters the inner liners of the combustors and partially or completely melts under the flames up to 2000 °C, at which point part of the ash deposits in the combustor fuel nozzle. Molten volcanic particles within high energy airflow escape the combustor to enter the turbine and impact the stationary (e.g., inlet nozzle guide vanes) and rotating airfoils (e.g., first stage high-pressure turbine blades) at high speed (up to Mach 1.25) in different directions, with the result that ash may stick, flow and remain liquid or solidify. Thus, the wetting behaviour of molten volcanic ash particle is fundamental to investigate impingement phenomena of ash droplet on the surface of real jet engine operation. The topic of wetting has received tremendous interest from both fundamental and applied points of view. However, due to the interdisciplinary gap between jet engine engineering and geology science, explicit investigation of wetting behaviour of volcanic ash at high temperature is in its infancy. We have taken a big step towards meeting this challenge. Here, we experimentally and theoretically investigate the wetting behaviour of viscous volcanic ash over a wide temperature range from 1100 to 1550 °C using an improved sessile-drop method. The results of our experiment demonstrate that temperature and viscosity play a critical role in determining the wetting possibility and governing the spreading kinetics of volcanic ash at high temperatures. Our systemic analysis of spreading of molten volcanic ash systems allows us to report on the fundamental differences between the mechanisms controlling spreading of organic liquids at room temperature and molten volcanic ash droplets.

  10. Near-real-time volcanic ash cloud detection: Experiences from the Alaska Volcano Observatory

    NASA Astrophysics Data System (ADS)

    Webley, P. W.; Dehn, J.; Lovick, J.; Dean, K. G.; Bailey, J. E.; Valcic, L.

    2009-09-01

    Volcanic eruptions produce ash clouds, which are a major hazard to population centers and the aviation community. Within the North Pacific (NOPAC) region, there have been numerous volcanic ash clouds that have reached aviation routes. Others have closed airports and traveled for thousands of kilometers. Being able to detect these ash clouds and then provide an assessment of their potential movement is essential for hazard assessment and mitigation. Remote sensing satellite data, through the reverse absorption or split window method, is used to detect these volcanic ash clouds, with a negative signal produced from spectrally semi-transparent ash clouds. Single channel satellite is used to detect the early eruption spectrally opaque ash clouds. Volcanic Ash Transport and Dispersion (VATD) models are used to provide a forecast of the ash clouds' future location. The Alaska Volcano Observatory (AVO) remote sensing ash detection system automatically analyzes satellite data of volcanic ash clouds, detecting new ash clouds and also providing alerts, both email and text, to those with AVO. However, there are also non-volcanic related features across the NOPAC region that can produce a negative signal. These can complicate alerts and warning of impending ash clouds. Discussions and examples are shown of these non-volcanic features and some analysis is provided on how these features can be discriminated from volcanic ash clouds. Finally, there is discussion on how information of the ash cloud such as location, particle size and concentrations, could be used as VATD model initialization. These model forecasts could then provide an improved assessment of the clouds' future movement.

  11. A new natural hazards data-base for volcanic ash and SO2 from global satellite remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Prata, F.; Stebel, K.

    2013-12-01

    Over the last few years there has been a recognition of the utility of satellite measurements to identify and track volcanic emissions that present a natural hazard to human populations. Mitigation of the volcanic hazard to life and the environment requires understanding of the properties of volcanic emissions, identifying the hazard in near real-time and being able to provide timely and accurate forecasts to affected areas. Amongst the many ways to measure volcanic emissions, satellite remote sensing is capable of providing global quantitative retrievals of important microphysical parameters such as ash mass loading, ash particle effective radius, infrared optical depth, SO2 partial and total column abundance, plume altitude, aerosol optical depth and aerosol absorbing index. The eruption of Eyjafjallajokull in April-May, 2010 led to increased research and measurement programs to better characterize properties of volcanic ash and the need to establish a data-base in which to store and access these data was confirmed. The European Space Agency (ESA) has recognized the importance of having a quality controlled data-base of satellite retrievals and has funded an activity (VAST) to develop novel remote sensing retrieval schemes and a data-base, initially focused on several recent hazardous volcanic eruptions. As a first step, satellite retrievals for the eruptions of Eyjafjallajokull, Grimsvotn, Puyhue-Cordon Caulle, Nabro, Merapi, Okmok, Kasatochi and Sarychev Peak are being considered. Here we describe the data, retrievals and methods being developed for the data-base. Three important applications of the data-base are illustrated related to the ash/aviation problem, to the impact of the Merapi volcanic eruption on the local population, and to estimate SO2 fluxes from active volcanoes-as a means to diagnose future unrest. Dispersion model simulations are also being included in the data-base. In time, data from conventional in situ sampling instruments, airborne and

  12. SURFACE AREA AND MICRO-ROUGHNESS OF VOLCANIC ASH PARTICLES: A case study, Acigol Volcanic Complex, Cappadocia, Central Turkiye

    NASA Astrophysics Data System (ADS)

    Ersoy, O.; Aydar, E.; Sen, E.; Atici, G.

    2009-04-01

    Every single ash particle may convey information about its own formation environment and conditions. Certain features on particles may give a hint about the fragmentation regime, the intensity of fragmentation and quantity of water that partakes in the fragmentation process, etc. On this account, this study majored in the analysis on finer pyroclastic material, namely volcanic ash particles. Here, we used volcanic ash particles from Quaternary Acigol Volcanic complex (West of Nevsehir, Cappadocia, Central Turkiye). Quaternary Acigol Volcanic complex lies between the towns of Nevsehir and Acigol. It consists of a shallow caldera, a thick pyroclastic apron, seven obsidian dome clusters, and scattered cinder cones and associated lavas (Druitt et al., 1995). The products of explosive volcanism of the region were distinguished as two main Quaternary tuffs by a recent study (Druitt et al., 1995). Samples are from ashfall beds in a sequence of intercalated pumice fall, ashfall, and ignimbrite beds. In this study in order to achieve surface properties of volcanic ash particles, surface areas and micro-roughness of ash particles were measured on digital elevation models (DEM) reconstructed from stereoscopic images acquired on Scanning Electron Microscope (SEM) at varying specimen tilt angles. Correlation between surface texture of volcanic ash particles and eruption characteristics was determined.

  13. Wind-blown volcanic ash in forest and agricultural locations as related to meteorological conditions

    NASA Astrophysics Data System (ADS)

    Fowler, W. B.; Lopushinsky, W.

    During the spring and summer of 1981, airborne ash previously deposited from the 1980 eruption of Mount St. Helens volcano was monitored at several field locations near the major axis of the depositional pattern in Washington State. Airborne ash was collected daily with standard high-volume samplers and other equipment that sampled the ash at selected windspeeds. Analysis of high-volume filtered deposits showed poor linear correlations to local meteorological conditions. At Moses Lake, weights of windspeed-selected samples indicated an exponential increase in suspended material with increasing windspeed. Wind tunnel tests with ash from two locations varying in distance from the volcano showed that the finer ash fractions from both locations became airborne at similar windspeeds. Threshold wind velocity was about 12 km h -1 for newly deposited ash, compared to more than 69 km h -1 for ash consolidated by wetting and drying.

  14. The respiratory health hazards of volcanic ash: a review for volcanic risk mitigation

    NASA Astrophysics Data System (ADS)

    Horwell, Claire J.; Baxter, Peter J.

    2006-07-01

    Studies of the respiratory health effects of different types of volcanic ash have been undertaken only in the last 40 years, and mostly since the eruption of Mt. St. Helens in 1980. This review of all published clinical, epidemiological and toxicological studies, and other work known to the authors up to and including 2005, highlights the sparseness of studies on acute health effects after eruptions and the complexity of evaluating the long-term health risk (silicosis, non-specific pneumoconiosis and chronic obstructive pulmonary disease) in populations from prolonged exposure to ash due to persistent eruptive activity. The acute and chronic health effects of volcanic ash depend upon particle size (particularly the proportion of respirable-sized material), mineralogical composition (including the crystalline silica content) and the physico-chemical properties of the surfaces of the ash particles, all of which vary between volcanoes and even eruptions of the same volcano, but adequate information on these key characteristics is not reported for most eruptions. The incidence of acute respiratory symptoms (e.g. asthma, bronchitis) varies greatly after ashfalls, from very few, if any, reported cases to population outbreaks of asthma. The studies are inadequate for excluding increases in acute respiratory mortality after eruptions. Individuals with pre-existing lung disease, including asthma, can be at increased risk of their symptoms being exacerbated after falls of fine ash. A comprehensive risk assessment, including toxicological studies, to determine the long-term risk of silicosis from chronic exposure to volcanic ash, has been undertaken only in the eruptions of Mt. St. Helens (1980), USA, and Soufrière Hills, Montserrat (1995 onwards). In the Soufrière Hills eruption, a long-term silicosis hazard has been identified and sufficient exposure and toxicological information obtained to make a probabilistic risk assessment for the development of silicosis in outdoor

  15. Volcanic eruptions, hazardous ash clouds and visualization tools for accessing real-time infrared remote sensing data

    NASA Astrophysics Data System (ADS)

    Webley, P.; Dehn, J.; Dean, K. G.; Macfarlane, S.

    2010-12-01

    Volcanic eruptions are a global hazard, affecting local infrastructure, impacting airports and hindering the aviation community, as seen in Europe during Spring 2010 from the Eyjafjallajokull eruption in Iceland. Here, we show how remote sensing data is used through web-based interfaces for monitoring volcanic activity, both ground based thermal signals and airborne ash clouds. These ‘web tools’, http://avo.images.alaska.edu/, provide timely availability of polar orbiting and geostationary data from US National Aeronautics and Space Administration, National Oceanic and Atmosphere Administration and Japanese Meteorological Agency satellites for the North Pacific (NOPAC) region. This data is used operationally by the Alaska Volcano Observatory (AVO) for monitoring volcanic activity, especially at remote volcanoes and generates ‘alarms’ of any detected volcanic activity and ash clouds. The webtools allow the remote sensing team of AVO to easily perform their twice daily monitoring shifts. The web tools also assist the National Weather Service, Alaska and Kamchatkan Volcanic Emergency Response Team, Russia in their operational duties. Users are able to detect ash clouds, measure the distance from the source, area and signal strength. Within the web tools, there are 40 x 40 km datasets centered on each volcano and a searchable database of all acquired data from 1993 until present with the ability to produce time series data per volcano. Additionally, a data center illustrates the acquired data across the NOPAC within the last 48 hours, http://avo.images.alaska.edu/tools/datacenter/. We will illustrate new visualization tools allowing users to display the satellite imagery within Google Earth/Maps, and ArcGIS Explorer both as static maps and time-animated imagery. We will show these tools in real-time as well as examples of past large volcanic eruptions. In the future, we will develop the tools to produce real-time ash retrievals, run volcanic ash dispersion

  16. Volcanic ash vs. sand and dust - "to stick or not to stick" in jet engines

    NASA Astrophysics Data System (ADS)

    Kueppers, U.; Song, W.; Lavallée, Y.; Hess, K. U.; Cimarelli, C.; Dingwell, D. B.

    2015-12-01

    Safe air travel activity requires clean flight corridors. But particles scattered in the atmosphere, whether volcanic ash, dust or sand, may present a critical threat to aviation safety. When these foreign particles are ingested into jet engines, whose interiors (e.g., the combustor and turbine blades) reach 1200-2000 °C, they can abrade, melt, and stick to the internal components of the engine, clogging ventilation traps of the cooling system as well as imparting substantial damage and potentially resulting in catastrophic system failure. To date, no criterion predicts ash behaviour at high temperature. Here, we experimentally develop the first quantitative model to predict melting and sticking conditions for the compositional range of volcanic ash encountered worldwide (Fig.1). The assumption that volcanic ash can be approximated by sand or dust is wholly inadequate, leading to an overestimation of sticking temperature and a correspondingly severe underestimation of the thermal hazard. Our findings confirm that the melting/softening behaviour of volcanic ash at high temperatures is essentially controlled by the composition of erupted ash - which may serve as an accurate proxy of the thermal hazard potential of volcanic ash interaction with jet engines. The criterion proposed here successfully parameterizes the potentially complex "melting" process of volcanic ash and can be used to assess the deposition probability of volcanic ash upon ingestion into hot jet engines.

  17. Nanoscale surface modification of Mt. Etna volcanic ashes

    NASA Astrophysics Data System (ADS)

    Barone, G.; Mazzoleni, P.; Corsaro, R. A.; Costagliola, P.; Di Benedetto, F.; Ciliberto, E.; Gimeno, D.; Bongiorno, C.; Spinella, C.

    2016-02-01

    Ashes emitted during volcanic explosive activity present peculiar surface chemical and mineralogical features related in literature to the interaction in the plume of solid particles with gases and aerosols. The compositional differences of magmas and gases, the magnitude, intensity and duration of the emission and the physical condition during the eruption, strongly influence the results of the modification processes. Here we report the characterization of the products emitted during the 2013 paroxysmal activity of Mt. Etna. The surface features of the ash particles were investigated through X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM) allowing the analysis at nanometer scale. TEM images showed on the surface the presence of composite structures formed by Ca, Mg and Na sulphates and halides and of droplets and crystals of chlorides; nanometric magnesioferrite and metallic iron dendrites are observable directly below the surface. From the chemical point of view, the most external layer of the volcanic glassy particles (<5 nm), analysed by XPS, presents depletion in Si, Mg, Ca, Na and K and strong enrichment in volatile elements especially F and S, with respect to the inner zone, which represents the unaltered counterpart. Below this external layer, a transition glassy shell (thick 50-100 nm) is characterized by Fe, Mg and Ca enrichments with respect to the inner zone. We propose that the ash particle surface composition is the result of a sequence of events which start at shallow depth, above the exsolution surface, where gas bubbles nucleate and the interfaces between bubbles and melt represent proto-surfaces of future ash particles. Enrichment of Ca, Mg and Fe and halides may be due to the early partition of F and Cl in the gas phase and their interaction with the melt layer located close to the bubbles. Furthermore the formation of volatile SiF4 and KF explain the observed depletion of Si and K. The F enrichment in the

  18. Aircraft and Volcanic Ash a Key Focus of EGU Meeting

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2010-05-01

    The erupting Eyjafjallajökull volcano in southern Iceland, which has intermittently disrupted European air traffic since 14 April, provided a dramatic backdrop for the recent European Geosciences Union (EGU) General Assembly in Vienna, Austria, about 2700 kilometers to the east. EGU organized several last-minute conference sessions about the eruption, and a number of scientists, including some from Iceland, discussed the latest situation, monitoring and assessment needs, and new guidance about flying through volcanic ash, which volcanologist and incoming EGU president-elect Donald Dingwell of the University of Munich, Germany, called “one of the ugliest cocktails nature throws up.” Although the eruption was small compared with those at Mount St. Helens in 1980 or Mount Pinatubo in 1991, the event produced an estimated 0.1 ± 0.05 cubic kilometer of tephra between 14 and 16 April, according to preliminary numbers from the Institute of Earth Sciences in Reykjavik, Iceland (see the related news item in this issue). An enormous amount of ash from the eruption got lofted into the jet stream toward the United Kingdom and the European mainland. European air traffic controllers, operating under the best guidance and guidelines available at that time—which indicated no flying in ash—shut down European air space to avoid a potential catastrophe if ash clogged up an aircraft's engines.

  19. The effects of volcanic ash disturbances on a peat-forming environment: environmental disruption and taphonomic consequences

    USGS Publications Warehouse

    Crowley, S.S.; Dufek, D.A.; Stanton, R.W.; Ryer, T.A.

    1994-01-01

    The maceral and palynological composition of the C coal bed (Upper Cretaceous), central Utah, was significantly affected by the periodic deposition of volcanic ash in the precursor peat mire. The coal bed contains four altered volcanic ash partings (tonsteins). We infer that deposition of the volcanic ash produced an environment conducive to the growth of ferns. We suggest that leaching of the volcanic ash created a semi-impermeable layer, which caused the ponding of surface water. -from Authors

  20. Remote sensing monitoring of volcanic ash clouds based on PCA method

    NASA Astrophysics Data System (ADS)

    Li, Chengfan; Dai, Yangyang; Zhao, Junjuan; Zhou, Shiqiang; Yin, Jingyuan; Xue, Dan

    2014-12-01

    Volcanic ash clouds threaten the aviation safety and cause global environmental effects. It is possible to effectively monitor the volcanic ash cloud with the aid of thermal infrared remote sensing technology. Principal component analysis (PCA) is able to remove the inter-band correlation and eliminate the data redundancy of remote sensing data. Taking the Eyjafjallajokull volcanic ash clouds formed on 15 and 19 April 2010 as an example, in this paper, the PCA method is used to monitor the volcanic ash cloud based on MODIS bands selection; the USGS standard spectral database and the volcanic absorbing aerosol index (AAI) are applied as contrasts to the monitoring result. The results indicate that: the PCA method is much simpler; its spectral matching rates reach 74.65 and 76.35%, respectively; and the PCA method has higher consistency with volcanic AAI distribution.

  1. Remote Sensing Monitoring of Volcanic Ash Clouds Based on PCA Method

    NASA Astrophysics Data System (ADS)

    Li, Chengfan; Dai, Yangyang; Zhao, Junjuan; Yin, Jingyuan; Xue, Dan

    2015-04-01

    Volcanic ash clouds threaten the aviation safety and cause global environmental effects. It is possible to effectively monitor the volcanic ash cloud with the aid of thermal infrared remote sensing technology. Principal component analysis (PCA) is able to remove the inter-band correlation and eliminate the data redundancy of remote sensing data. Taking the Eyjafjallajokull volcanic ash clouds formed on 15 and 19 April 2010 as an example, in this paper, the PCA method is used to monitor the volcanic ash cloud based on MODIS bands selection; the USGS standard spectral database and the volcanic absorbing aerosol index (AAI) are applied as contrasts to the monitoring result. The results indicate that: the PCA method is much simpler; its spectral matching rates reach 74.65 and 76.35%, respectively; and the PCA method has higher consistency with volcanic AAI distribution.

  2. Engine Damage to a NASA DC-8-72 Airplane From a High-Altitude Encounter With a Diffuse Volcanic Ash Cloud

    NASA Technical Reports Server (NTRS)

    Grindle, Thomas J.; Burcham, Frank W., Jr.

    2003-01-01

    The National Aeronautics and Space Administration (NASA) DC-8 airborne sciences research airplane inadvertently flew through a diffuse volcanic ash cloud of the Mt. Hekla volcano in February 2000 during a flight from Edwards Air Force Base (Edwards, California) to Kiruna, Sweden. Although the ash plume was not visible to the flight crew, sensitive research experiments and instruments detected it. In-flight performance checks and postflight visual inspections revealed no damage to the airplane or engine first-stage fan blades; subsequent detailed examination of the engines revealed clogged turbine cooling air passages. The engines were removed and overhauled. This paper presents volcanic ash plume analysis, trajectory from satellites, analysis of ash particles collected in cabin air heat exchanger filters and removed from the engines, and data from onboard instruments and engine conditions.

  3. Effects Of Crystallographic Properties On The Ice Nucleation Properties Of Volcanic Ash Particles

    SciTech Connect

    Kulkarni, Gourihar R.; Nandasiri, Manjula I.; Zelenyuk, Alla; Beranek, Josef; Madaan, Nitesh; Devaraj, Arun; Shutthanandan, V.; Thevuthasan, Suntharampillai; Varga, Tamas

    2015-04-28

    Specific chemical and physical properties of volcanic ash particles that could affect their ability to induce ice formation are poorly understood. In this study, the ice nucleating properties of size-selected volcanic ash and mineral dust particles in relation to their surface chemistry and crystalline structure at temperatures ranging from –30 to –38 °C were investigated in deposition mode. Ice nucleation efficiency of dust particles was higher compared to ash particles at all temperature and relative humidity conditions. Particle characterization analysis shows that surface elemental composition of ash and dust particles was similar; however, the structural properties of ash samples were different.

  4. How accurate are volcanic ash simulations of the 2010 Eyjafjallajökull eruption?

    NASA Astrophysics Data System (ADS)

    Dacre, Helen; Harvey, Natalie; Webley, Peter; Morton, Don

    2016-04-01

    In the event of a volcanic eruption the decision to close airspace is based on forecast ash maps, produced using volcanic ash transport and dispersion models. In this paper we quantitatively evaluate the spatial skill of volcanic ash simulations using satellite retrievals of ash from the Eyjafjallajökull eruption during the period from 7-16 May 2010. We find that at the start of this period, 7-10 May, the model (FLEXPART) has excellent skill and can predict the spatial distribution of the satellite retrieved ash to within 0.5°× 0.5° lat/lon. However, on the 10 May there is a decrease in the spatial accuracy of the model, to 2.5°× 2.5° lat/lon, and between 11-12 May the simulated ash location errors grow rapidly. On the 11 May ash is located close to a bifurcation point in the atmosphere, resulting in a rapid divergence in the modeled and satellite ash locations. In general, the model skill reduces as the residence time of ash increases. However, the error growth is not always steady. Rapid increases in error growth are linked to critical points in the ash trajectories. Ensemble modeling using perturbed meteorological data would help to represent this uncertainty and assimilation of satellite ash data would help to reduce uncertainty in volcanic ash forecasts.

  5. Volcanic-Ash Hazards to Aviation—Changes and Challenges since the 2010 Eruption of Eyjafjallajökull, Iceland

    NASA Astrophysics Data System (ADS)

    Guffanti, M.; Tupper, A.; Mastin, L. G.; Lechner, P.

    2012-12-01

    In response to the severe disruptions to civil aviation that resulted from atmospheric transport of ash from the eruption of Eyjafjallajökull volcano in Iceland in April and May 2010, the International Civil Aviation Organization (ICAO) quickly formed the International Volcanic Ash Task Force (IVATF), charging it to support the accelerated development of a global risk-management framework for volcanic-ash hazards to aviation. Recognizing the need for scientifically based advice on best methods to detect ash in the atmosphere and depict zones of hazardous airspace, the IVATF sought input from the global scientific community, primarily by means of the Volcanic Ash Scientific Advisory Group which was established in May 2010 by the World Meteorological Organization (WMO) and International Union of Geodesy and Geophysics to serve as a scientific resource for ICAO. The IVATF finished its work in June 2012 (see http://www.icao.int/safety/meteorology/ivatf/Pages/default.aspx for a record of its results). A major science-based outcome is that production of charts depicting areas of airspace expected to have specific ash-concentration values (e.g. <0.2, 0.2-2, 2-4, >4 mg/cu. m) will not be required of the world's nine Volcanic Ash Advisory Centers (VAACs). The VAACs are responsible for issuing warning information to the aviation sector regarding ash-cloud position and expected movement. Forecast concentrations in these charts are based primarily on dispersion models that have at least an order of magnitude in uncertainty in their output and therefore do not delineate hazardous airspace with the level of confidence needed by the aviation sector. The recommended approach to improving model-forecast accuracy is to assimilate diverse observations (e.g., satellite thermal-infrared measurements, lidar, radar, direct airborne sampling, visual sightings, etc.) into model simulations; doing that during an eruption in the demanding environment of aviation operations is a substantial

  6. Validation of ash optical depth and layer height retrieved from passive satellite sensors using EARLINET and airborne lidar data: the case of the Eyjafjallajökull eruption

    NASA Astrophysics Data System (ADS)

    Balis, Dimitris; Koukouli, Maria-Elissavet; Siomos, Nikolaos; Dimopoulos, Spyridon; Mona, Lucia; Pappalardo, Gelsomina; Marenco, Franco; Clarisse, Lieven; Ventress, Lucy J.; Carboni, Elisa; Grainger, Roy G.; Wang, Ping; Tilstra, Gijsbert; van der A, Ronald; Theys, Nicolas; Zehner, Claus

    2016-05-01

    The vulnerability of the European airspace to volcanic eruptions was brought to the attention of the public and the scientific community by the 2010 eruptions of the Icelandic volcano Eyjafjallajökull. As a consequence of this event, ash concentration thresholds replaced the "zero tolerance to ash" rule, drastically changing the requirements on satellite ash retrievals. In response to that, the ESA funded several projects aiming at creating an optimal end-to-end system for volcanic ash plume monitoring and prediction. Two of them, namely the SACS-2 and SMASH projects, developed and improved dedicated satellite-derived ash plume and sulfur dioxide level assessments. The validation of volcanic ash levels and height extracted from the GOME-2 and IASI instruments on board the MetOp-A satellite is presented in this work. EARLINET lidar measurements are compared to different satellite retrievals for two eruptive episodes in April and May 2010. Comparisons were also made between satellite retrievals and aircraft lidar data obtained with the UK's BAe-146-301 Atmospheric Research Aircraft (managed by the Facility for Airborne Atmospheric Measurements, FAAM) over the United Kingdom and the surrounding regions. The validation results are promising for most satellite products and are within the estimated uncertainties of each of the comparative data sets, but more collocation scenes would be desirable to perform a comprehensive statistical analysis. The satellite estimates and the validation data sets are better correlated for high ash optical depth values, with correlation coefficients greater than 0.8. The IASI retrievals show a better agreement concerning the ash optical depth and ash layer height when compared with the ground-based and airborne lidar data.

  7. Regional model studies of the atmospheric dispersion of fine volcanic ash after the eruption of Eyjafjallajoekull

    NASA Astrophysics Data System (ADS)

    Langmann, B.; Hort, M. K.

    2010-12-01

    During the eruption of Eyjafjallajoekull on Iceland in April/May 2010 air traffic over Europe was repeatedly interrupted because of volcanic ash in the atmosphere. This completely unusual situation in Europe leads to the demand of improved crisis management, e.g. European wide regulations of volcanic ash thresholds and improved forecasts of theses thresholds. However, the quality of the forecast of fine volcanic ash concentrations in the atmosphere depends to a great extent on a realistic description of the erupted mass flux of fine ash particles, which is rather uncertain. Numerous aerosol measurements (ground based and satellite remote sensing, and in situ measurements) all over Europe have tracked the volcanic ash clouds during the eruption of Eyjafjallajoekull offering the possibility for an interdisciplinary effort between volcanologists and aerosol researchers to analyse the release and dispersion of fine volcanic ash in order to better understand the needs for realistic volcanic ash forecasts. This contribution describes the uncertainties related to the amount of fine volcanic ash released from Eyjafjallajoekull and its influence on the dispersion of volcanic ash over Europe by numerical modeling. We use the three-dimensional Eulerian atmosphere-chemistry/aerosol model REMOTE (Langmann et al., 2008) to simulate the distribution of volcanic ash as well as its deposition after the eruptions of Eyjafjallajoekull during April and May 2010. The model has been used before to simulate the fate of the volcanic ash after the volcanic eruptions of Kasatochi in 2008 (Langmann et al., 2010) and Mt. Pinatubo in 1991. Comparing our model results with available measurements for the Eyjafjallajoekull eruption we find a quite good agreement with available ash concentrations data measured over Europe as well as with the results from other models. Langmann, B., K. Zakšek and M. Hort, Atmospheric distribution and removal of volcanic ash after the eruption of Kasatochi volcano

  8. NASA Applied Science Program Applications for the Volcanic Ash Threat to Aviation

    NASA Astrophysics Data System (ADS)

    Murray, J. J.; Haynes, J. A.; Lindsay, F.

    2012-12-01

    Over the past decade, the public interest has been increasingly focused on the significant safety and economic impacts of the volcanic ash threat to aviation. During this period, the NASA Applied Science Program has developed a significant number of critical volcanic ash applications for a wide range of cutting-edge NASA satellite observations. This has entailed the development of many new and innovative technical advances and these advances have enabled and are increasingly improving the accuracy and the utility of volcanic ash advisories worldwide. The development of these applications is examined with respect to the specific sensor technologies, their pedigree and legacy, their unique and critical data for volcanic ash detection or characterization, volcanic ash algorithm development and validation and, finally, the use and impact of these applications. This substantial legacy rests on NASA Earth Observing Satellites and their advanced data. Imager applications for the The MODerate Resolution Imaging Spectro-radiometer (MODIS) instrument onboard NASA Terra and Aqua spacecraft and the Visible Infrared Imager Radiometer Suite (VIIRS) instrument onboard Suomi NPP allow better discrimination of ash from water vapor and ice clouds than traditional split-window imager techniques, as well as improved height assignment. Chemistry and aerosol applications for the Ozone Monitoring Instrument (OMI) onboard the NASA Aura spacecraft and the Ozone Mapper and Profiler Suite (OMPS) onboard Suomi NPP produce improved horizontal dispersion maps, and indices for volcanic ash and sulfate aerosol concentrations. Applications for the Caliop lidar onboard the NASA Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite provide very accurate estimates of volcanic ash altitude, layering and concentration. These are critical assimilation elements for volcanic ash dispersion models and forecasts. The Multi-angle Imaging SpectroRadiometer (MISR) instrument

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

    NASA Astrophysics Data System (ADS)

    Durant, Adam J.; Villarosa, Gustavo; Rose, William I.; Delmelle, Pierre; Prata, Alfred J.; Viramonte, José G.

    2012-01-01

    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 0.4 Tg 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 (>80 km) ash deposit was poorly sorted and fine grained, and mean particle size varied very little beyond a distance >300 km. There were three particle size subpopulations in fallout at distances >300 km 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

  10. Nature, source and composition of volcanic ash in surficial sediments around the Zhongsha Islands

    NASA Astrophysics Data System (ADS)

    Yan, Quanshu; Shi, Xuefa; Wang, Xinyu

    2008-05-01

    Volcanic detrital sediments are a unique indicator for reconstructing the petrogenetic evolution of submarine volcanic terrains. Volcanic ash in surficial sediments around the Zhongsha Islands includes three kinds of volcanogenic detritus, i.e., brown volcanic glass, colorless volcanic glass and volcanic scoria. The major element characteristics show that bimodal volcanic activity may have taken place in the northern margin of the South China Sea, with brown volcanic glass and colorless volcanic glass representing the mafic end-member and felsic end-member, respectively. Fractional crystallization is the main process for magma evolution. The nature of the volcanic activity implies that the origin of volcanic activity was related to extensional tectonic settings, which is corresponding to an extensional geodynamic setting in the Xisha Trench, and supports the notion, which is based on geophysical data and petrology, that there may exist a mantle plume around the Hainan Island.

  11. Environmental and anthropogenic factors affecting the respiratory toxicity of volcanic ash in vitro

    NASA Astrophysics Data System (ADS)

    Tomašek, Ines; Horwell, Claire J.; Damby, David E.; Ayris, Paul M.; Barošová, Hana; Geers, Christoph; Petri-Fink, Alke; Rothen-Rutishauser, Barbara; Clift, Martin J. D.

    2016-04-01

    Human exposure to inhalable volcanic ash particles following an eruption is a health concern, as respirable-sized particles can potentially contribute towards adverse respiratory health effects, such as the onset or exacerbation of respiratory and cardiovascular diseases. Although there is substantial information on the mineralogical properties of volcanic ash that may influence its biological reactivity, knowledge as to how external factors, such as air pollution, contribute to and augment the potential reactivity is limited. To determine the respiratory effects of volcanic particle interactions with anthropogenic pollution and volcanic gases we will experimentally assess: (i) physicochemical characteristics of volcanic ash relevant to respiratory toxicity; (ii) the effects of simultaneously inhaling anthropogenic pollution (i.e. diesel exhaust particles (DEP)) and volcanic ash (of different origins); (iii) alteration of volcanic ash toxicity following interaction with volcanic gases. In order to gain a first understanding of the biological impact of the respirable fraction of volcanic ash when inhaled with DEP in vitro, we used a sophisticated 3D triple cell co-culture model of the human alveolar epithelial tissue barrier. The multi-cellular system was exposed to DEP [0.02 mg/mL] and then exposed to either a single or repeated dose of well-characterised respirable volcanic ash (0.26 ± 0.09 or 0.89 ± 0.29 μg/cm2, respectively) from the Soufrière Hills volcano, Montserrat for a period of 24 hours using a pseudo-air liquid interface approach. Cultures were subsequently assessed for adverse biological endpoints including cytotoxicity, oxidative stress and (pro)-inflammatory responses. Results indicated that the combination of DEP and respirable volcanic ash at sub-lethal concentrations incited a significant release of pro-inflammatory markers that was greater than the response for either DEP or volcanic ash, independently. Further work is planned, to determine if

  12. Iron Fertilization by Volcanic Ash in the Cenomanian/Turonian Western Interior Seaway

    NASA Astrophysics Data System (ADS)

    Zeng, Z.; Tice, M. M.; Xu, G.; Hatcheria, J.; Sulak, C.; Rucker, B.; Gao, Z.; Maulana, I.; Figueroa, C.; Nimmo, L.; Gutkowski, B.; Dougherty, B.; Mattson, A.; Gillespie, D.; Wood, E.; Wehner, M.; Conte, R.

    2014-12-01

    Volcanic ash contains 1-10% FeO by weight and can be a significant contributor of Fe to the surface ocean. It is possible that Fe fertilization by volcanic ash has contributed to marine productivity in the past. The Late Cretaceous Eagle Ford Group (Cenomanian/Turonian) contains abundant volcanic ash beds interbedded with black argillaceous limestones and calcareous mudstones, providing opportunities for observation of the influence of ash on productivity and basin chemistry in the Western Interior Seaway. In particular, we hypothesize that volcanic ash from nearby arc volcanoes stimulated productivity by providing reactive iron to the surface ocean that was otherwise nutrient-limited by poor ventilation in a stratified water column. Enhanced productivity likewise reinforced basinal anoxia. To test our hypothesis, we examined the Swenson #1 core (151 feet) from McMullen County, south Texas, which contains 51 visualized ash beds with varying thickness. High resolution x-ray fluorescence spectroscopy (5 mm), x-ray fluorescence microscopy (100 μm) and scanning electron microscopy were performed to examine burial of Fe, trace elements delivered to the sediment by sinking organic matter (Cu and Ba), and paleoredox proxies (Mo and Cr) below, in, and above ash beds. Ash beds and beds containing admixed ash contain much more Fe than interbedded black shales, with nearly all Fe present in pyrite intergrown with or partially replacing altered ash grains, suggesting that ash transported reactive Fe to otherwise Fe-poor settings. Concentrations of Cu, Ba, Mo, and Cr were significantly greater in beds with admixed ash than in underlying beds. This suggests that input of ash increased marine productivity (Cu and Ba), which in turn enhanced oxygen demand and promoted euxinia (Mo and Cr). We conclude that Fe-bearing volcanic ash fertilized the southern Cenomanian/Turonian Western Interior Seaway, episodically forcing or enhancing euxinia both before and after OAE2.

  13. Gas/aerosol-ash interaction in volcanic plumes: New insights from surface analyses of fine ash particles

    NASA Astrophysics Data System (ADS)

    Delmelle, Pierre; Lambert, Mathieu; Dufrêne, Yves; Gerin, Patrick; Óskarsson, Niels

    2007-07-01

    The reactions occurring between gases/aerosols and silicate ash particles in volcanic eruption plumes remain poorly understood, despite the fact that they are at the origin of a range of volcanic, environmental, atmospheric and health effects. In this study, we apply X-ray photoelectron spectroscopy (XPS), a surface-sensitive technique, to determine the chemical composition of the near-surface region (2-10 nm) of nine ash samples collected from eight volcanoes. In addition, atomic force microscopy (AFM) is used to image the nanometer-scale surface structure of individual ash particles isolated from three samples. We demonstrate that rapid acid dissolution of ash occurs within eruption plumes. This process is favoured by the presence of fluoride and is believed to supply the cations involved in the deposition of sulphate and halide salts onto ash. AFM imaging also has permitted the detection of extremely thin (< 10 nm) coatings on the surface of ash. This material is probably composed of soluble sulphate and halide salts mixed with sparingly soluble fluoride compounds. The surface approach developed here offers promising aspects for better appraising the role of gas/aerosol-ash interaction in dictating the ability of ash to act as sinks for various volcanic and atmospheric chemical species as well as sources for others.

  14. Assimilation of satellite-retrieved data to improve forecasts of volcanic ash concentrations

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Lin, Haixiang; Heemink, Arnold; Segers, Arjo; Lu, Sha

    2016-04-01

    Since the 2010 Eyjafjallajökull volcano eruption caused a big problem to aviation and economy, improvement on volcanic ash forecast has been put onto the research agenda. Satellite-based measurements are considered as the most common and cheapest type of volcanic ash observations. However, due to its intrinsic functionality, satellite-retrived two-dimensional data can not be easily and directly combined with a three-dimensional volcanic ash model to improve volcanic ash forecasts continuously. Here we propose a satellite observational operator to transfer 2D volcanic ash mass loadings to 3D concentrations. The uncertainties of reconstructed 3D ash concentrations are also quantified. Sequential data assimilation is used to continuously assimilate the reconstructed volcanic ash concentrations. The results are evaluated in a multi-observational network including satellite-based measurements and aircraft in-situ measurements. Here we show for long-time assimilating satellite-based measurements, Ensemble Squre Root Filter (EnSR), as a common sequential data assimilation technique, is more efficient than Ensemble Kalman Filter (EnKF) because the ensemble size required for EnSR is considerable less than the ensemble size of EnKF for a comparable assimilation performance. Moreover, the forecast after assimilation is validated to be accurate and valid within 15 hours.

  15. Volcanic Ash Impacts on Air Traffic from the 2009 Mt. Redoubt Eruption

    NASA Astrophysics Data System (ADS)

    Murray, J. J.; Matus, A. V.; Hudnall, L. A.; Krueger, A. J.; Haynes, J. A.; Pippin, M. R.

    2009-12-01

    The dispersion of volcanic ash during the March 2009 eruption of Mt. Redoubt created the potential for major problems for aviation. Mt. Redoubt is located 110 km west-southwest of Alaska Airlines hub in Anchorage. It last erupted in 1990 and caused an estimated $101 million cost to the aviation industry (Waythomas, 1998). This study was conducted to assist in improving warning systems, policy and procedures for addressing the impact of volcanic ash on aviation. The study had two primary components. First, the altitude and extent of SO2 dispersion was determined through analysis of synoptic meteorological conditions and satellite imagery. Second, impacts on aviation from the volcanic ash dispersion were investigated. OMI SO2 column measurements were employed to assess the altitude and extent of SO2 dispersion of volcanic ash. To accomplish this, OMI data were assimilated with CALIPSO backscatter profiles, geopotential height plots, and HYSPLIT forward model trajectories. Volcanic Ash Advisories were compared to airport and pilot reports to assess aviation impacts. The eruption produced a complex dispersion of volcanic ash. Volcanic ash altitudes estimated for 23 March 2009 indicate that the majority of the plume remained at approximately 8 km, although reports indicate that the initial plume may have reached as high as18 km (60,000 ft). A low pressure system which passed over the eruption area appears to have entrained most of the ash at approximately 8 km, however the CALIPSO satellite indicates that dispersion also extended to 10 km and 16 km. Atmospheric patterns suggest dispersion at approximately 3 km near Hudson Bay. Analysis of 25 March 2009 indicates that much of the ash plume was dispersed at higher altitudes, where CALIPSO data locates the stratospheric ash plume at approximately 14 km above mean sea level. By the time the eruptions had subsided in April, Alaska Airlines had cancelled 295 flights and disrupted the flights of over 20,000 passengers. This

  16. Estimation of volcanic ash emissions from satellite data using trajectory-based 4D-Var

    NASA Astrophysics Data System (ADS)

    Lu, Sha; Lin, Haixiang; Heemink, Arnold; Segers, Arjo; Fu, Guangliang

    2016-04-01

    An accurate determination of emission parameters are crucial to the volcanic ash forecast for aviation, health and climate interests. In this study, we reconstruct the vertical profile of the volcanic ash emission from satellite ash mass loading data using trajectory-based 4D-Var (Trj4DVar) approach with Eyjafjallajökull 2010 eruptive event and the corresponding SEVIRI data as a study case. Since the Eyjafjallajökull eruption in April 2010, besides ash mass loadings retrieved from satellite data, the additional information of plume height and mass eruption rate is always available from volcanic ash detections and observations. Modifications is made in Trj4DVar to integrate the additional information into the data assimilation system to improve the estimation of volcanic ash emissions and achieve a better initial condition for quantitative predictions. The modified Trj4DVar has been tested in twin experiments designed based on the study case, and shows significant improvement on straightforward Trj4DVar since it has great correction impact to recognize the injection height and produce more accurate emission estimation and reliable initial field of volcanic ash loading. To apply the approach to the real case with SEVIRI data, two strategies was proposed: observational mask matrix and separate time windows. The results produced a better initial condition and predictive forecast that were more fitter the SEVIRI ash mass loading fields, which showed a great potential of applying the method in practice.

  17. On the impact of additional spectral bands usage on RST-ASH performance in volcanic ash plume detected from space

    NASA Astrophysics Data System (ADS)

    Falconieri, Alfredo; Filizzola, Carolina; Marchese, Francesco; Pergola, Nicola; Tramutoli, Valerio

    2016-04-01

    RST-ASH is an algorithm developed for detecting and tracking volcanic ash clouds from space based on the Robust Satellite Technique (RST) multi-temporal approach. For the identification of ash affected areas RST-ASH uses two local variation indexes in combination. They analyse the Brightness Temperature Differences (BTD) of the signal measured at 11 μm and 12 μm and at around 3.5 and 11 μm wavelengths to detect ash in both nighttime and daytime conditions. RST-ASH was tested on Advanced Very High Resolution Radiometer (AVHRR) and on Moderate Resolution Imaging Spectroradiometer (MODIS) records and was then implemented on Spinning Enhanced Visible and Infrared Imager (SEVIRI) for studying and monitoring eruptions of different volcanoes. In this study, some experimental configurations of RST-ASH, analyzing signal also in other spectral bands (e.g. VIS, SO2) will be tested and assessed, studying recent ash plumes (e.g. Etna, Eyjafjallajökull, Grímsvötn) affecting different geographic areas. Results achieved using both polar and geostationary satellite data will be evaluated even for comparison with other state of the art methods. The work shows that when the extended spectral capabilities offered by high temporal resolution satellites are exploited an improvement of RST-ASH performance in some observational and plume conditions is achievable, making RST-ASH still more suited for identifying and monitoring ash clouds in the framework of possible operational scenarios.

  18. Development of Satellite Remote Sensing Techniques for Quantifying Volcanic Ash Cloud Properties

    NASA Astrophysics Data System (ADS)

    Pavolonis, Michael J.

    Novel new approaches to automatically detect and characterize volcanic ash using satellite data are presented. The Spectrally Enhanced Cloud Objects (SECO) ash detection algorithm, combines radiative transfer theory, Bayesian methods, and image processing/computer vision concepts to identify volcanic ash clouds in satellite data with skill that is generally comparable to a human expert, especially with respect to false alarm rate. The SECO method is globally applicable and can be applied to virtually any low earth orbit or geostationary satellite sensor. The new ash detection approach was quantitatively proven to be significantly more skillful than traditional pixel based approaches, including the commonly used "split-window" technique. The performance of the SECO approach is extremely promising and well suited for a variety of new and improved applications. A new approach to retrieve volcanic ash cloud properties from infrared satellite measurements was also developed. The algorithm utilizes an optimal estimation framework to retrieve ash cloud height, mass loading, and effective particle radius. Optimal estimation allows uncertainties in the measurements and forward model to be taken into account and uncertainty estimates for each of the retrieved parameters to be determined. Background atmospheric water vapor, surface temperature, and surface emissivity are explicitly accounted for on a pixel-by-pixel basis, so the algorithm is globally applicable. In addition, the ash cloud retrieval algorithm is unique because it allows the cloud temperature/height to be a free parameter. Volcanic ash clouds are a major aviation hazard. Fine-grained ash from explosive eruptions can be transported long distances (>1000 km) from the source volcano by atmospheric winds, severely disrupting aviation operations. Volcanic ash clouds are complex and the background environment in which they reside can be as well. Thus, sophisticated satellite remote sensing techniques for extracting

  19. Characterization of fine volcanic ash from explosive eruption from Sakurajima volcano, South Japan

    NASA Astrophysics Data System (ADS)

    Nanayama, F.; Furukawa, R.; Ishizuka, Y.; Yamamoto, T.; Geshi, N.; Oishi, M.

    2013-12-01

    Explosive volcanic eruptions can affect infrastructure and ecosystem by their dispersion of the volcanic particle. Characterization of volcanic particle expelled by explosive eruption is crucial for evaluating for quantitative hazard assessment by future volcanic eruption. Especially for fine volcanic ash less than 64 micron in diameter, it can disperse vast area from the source volcano and be easily remobilized by surface wind and precipitation after the deposition. As fine volcanic ash is not preserved well at the earth surface and in strata except for enormously large scale volcanic eruption. In order to quantify quantitative characteristics of fine volcanic ash particle, we sampled volcanic ash directly falling from the eruption cloud from Showa crater, the most active vent of Sakurajima volcano, just before landing on ground. We newly adopted high precision digital microscope and particle grain size analyzer to develop hazard evaluation method of fine volcanic ash particle. Field survey was performed 5 sequential days in January, 2013 to take tamper-proof volcanic ash samples directly obtained from the eruption cloud of the Sakurajima volcano using disposable paper dishes and plastic pails. Samples were taken twice a day with time-stamp in 40 localities from 2.5 km to 43 km distant from the volcano. Japan Meteorological Agency reported 16 explosive eruptions of vulcanian style occurred during our survey and we took 140 samples of volcanic ash. Grain size distribution of volcanic ash was measured by particle grain size analyzer (Mophologi G3S) detecting each grain with parameters of particle diameter (0.3 micron - 1 mm), perimeter, length, area, circularity, convexity, solidity, and intensity. Component of volcanic ash was analyzed by CCD optical microscope (VHX-2000) which can take high resolution optical image with magnifying power of 100-2500. We discriminated each volcanic ash particle by color, texture of surface, and internal structure. Grain size

  20. Comparative in vitro cytotoxicity of volcanic ashes from Mount St. Helens, El Chichon, and Galunggung.

    PubMed

    Vallyathan, V; Robinson, V; Reasor, M; Stettler, L; Bernstein, R

    1984-01-01

    Dry sedimented volcanic ash samples from each of three widely separated volcanoes of the "Circum Pacific" region have been subjected to mineralogic analysis and in vitro tests for cytotoxicity. The ash samples from the three different volcanoes varied in particle size, surface area, and concentration of silica. Total crystalline silica in the respirable fraction of ashes was 1.5% (Mount St. Helens, Moses Lake); 1.36% (Galunggung, Bandung-1); 1.95% (Gallunggung, Bandung-2); and 1.72% (El Chichon, Tuxtla). Hemolysis as an index of cytotoxicity was measured by in vitro tests on sheep blood erythrocytes and indicated wide differences in hemolytic activity among ash samples. Alveolar macrophage cytosolic (lactate dehydrogenase) and lysosomal (beta-glucuronidase and beta-N-acetyl glucosaminidase) enzymes were measured as an index of cellular integrity following dust exposure. Hemolysis and release of enzymes from alveolar macrophages were greater with volcanic ash from Galunggung (Bandung-1) and El Chichon (Tuxtla) than the other ashes. Although crystalline silica induced an effect similar to volcanic ash from Galunggung (Bandung-1) on the release of enzymes from alveolar macrophages, the hemolytic potency of silica was much greater. Light and electron microscopic observations of dust-exposed alveolar macrophages indicated that the ash particles were readily phagocytized. These results indicate that volcanic ash is moderately cytotoxic and that exposure may lead to overt reactions and the exacerbation of preexisting chronic inflammatory processes. PMID:6097694

  1. Volcanic ash as an iron-fertilizer in ocean surface water

    NASA Astrophysics Data System (ADS)

    Olgun, N.; Duggen, S.; Croot, P.; Dietze, H.; Schacht, U.; Oskarsson, N.; Siebe, C.; Auer, A.

    2007-12-01

    Surface ocean fertilisation with iron may affect the marine primary productivity, C-cycles and eventually climate development. Volcanic ash has the potential to release iron on contact with seawater and to stimulate phytoplankton growth (1,2) but the relative importance of volcanism at destructive plate margins (subduction zones, SZ) and intraplate volcanic settings (ocean islands at hot spots) remains unknown. Here we present new results from geochemical experiments with natural seawater and numerous volcanic ash samples from SZ volcanoes in the Pacific Ring of Fire (Alaska, Japan, Kamchatka, Northern and Central America and Papua New Guinea) and hot spot volcanoes (on Iceland and Hawaii). The release of iron as a function of time was determined in situ in seawater by means of Cathodic Stripping Voltammetry. Our experiments show that: A) volcanic ash from both SZ and hot spot volcanic areas mobilise significant amounts of iron, B) with the highest mobilisation rates within the first 10-20 minutes and C) indicate that volcanic ash from hot spot volcanoes mobilise less iron than volcanic ash from SZ. We propose that the higher iron-mobilisation potential of SZ volcanic ash results from higher HCl/HF ratios in SZ volcanic gases that seem to be involved in the formation of Fe-bearing soluble salt coatings (condensed gases and adsorbed aerosols) on ash particles (1,2,3). Higher HCl/HF ratios in SZ volcanic gases thus appear to be linked to the recycling of seawater through subduction of oceanic lithosphere at destructive plate margins. Together, taking into account differences in ash-fluxes from SZ and hot spot volcanoes into the oceans, our study suggests that SZ volcanic ash plays a more important role for the global surface ocean iron budget than ash from volcanoes in hot spot areas. 1 Frogner, Gislason, Oskarsson (2001). Geology, 29, 487-490. 2 Duggen, Croot, Schacht, Hofmann (2007) Geoph. Res. Letters 34, 5. 3 Oskarsson (1980), J. Volc. and Geoth. Res. 8, 251-266.

  2. Effect of Particle Non-Sphericity on Satellite Monitoring of Drifting Volcanic Ash Clouds

    NASA Technical Reports Server (NTRS)

    Krotkov, Nicholay A.; Flittner, D. E.; Krueger, A. J.; Kostinski, A.; Riley, C.; Rose, W.

    1998-01-01

    Volcanic eruptions loft gases and ash particles into the atmosphere and produce effects that are both short term (aircraft hazards, interference with satellite measurements) and long term (atmospheric chemistry, climate). Large (greater than 0.5mm) ash particles fall out in minutes [Rose et al, 1995], but fine ash particles can remain in the atmosphere for many days. This fine volcanic ash is a hazard to modem jet aircraft because the operating temperatures of jet engines are above the solidus temperature of volcanic ash, and because ash causes abrasion of windows and airframe, and disruption of avionics. At large distances(10(exp 2)-10(exp 4) km or more) from their source, drifting ash clouds are increasingly difficult to distinguish from meteorological clouds, both visually and on radar [Rose et al., 1995]. Satellites above the atmosphere are unique platforms for viewing volcanic clouds on a global basis and measuring their constituents and total mass. Until recently, only polar AVHRR and geostationary GOES instruments could be used to determine characteristics of drifting volcanic ash clouds using the 10-12 micron window [Prata 1989; Wen and Rose 1994; Rose and Schneider 1996]. The NASA Total Ozone Mapping Spectrometer (TOMS) instruments aboard the Nimbus-7, Meteor3, ADEOS, and Earth Probe satellites have produced a unique data set of global SO2 volcanic emissions since 1978 (Krueger et al., 1995). Besides SO2, a new technique has been developed which uses the measured spectral contrast of the backscattered radiances in the 330-380nm spectral region (where gaseous absorption is negligible) in conjunction with radiative transfer models to retrieve properties of volcanic ash (Krotkov et al., 1997) and other types of absorbing aerosols (Torres et al., 1998).

  3. Volcanic ash ingestion by a large gas turbine aeroengine: fan-particle interaction

    NASA Astrophysics Data System (ADS)

    Vogel, Andreas; Clarkson, Rory; Durant, Adam; Cassiani, Massimo; Stohl, Andreas

    2016-04-01

    Airborne particles from explosive volcanic eruptions are a major safety threat for aviation operations. The fine fraction of the emitted particles (<63 microns diameter) may remain in the atmosphere for days, or even weeks, and can affect commercial air traffic routes. Over the past century, there have been a considerable number of aircraft encounters with drifting volcanic ash clouds. Particles ingested into the engine cause erosion of upstream surfaces of compressor fan blades and rotor-path components, and can also cause contamination or blockage of electrical systems and the fuel system such as fuel nozzles and air bleed filters. Ash particles that enter the hot-section of the engine (combustor and turbine stages; temperature between 1400-1800°C) are rapidly heated above the glass transition temperature (about 650-1000°C) and become soft (or form a melt) and can stick as re-solidified deposits on nozzle guide vanes. The glass deposits change the internal aerodynamic airflow in the engine and can affect the cooling capability of the different components by clogging the cooling inlets/outlets, which can lead to a loss of power or flame-out. The nature of volcanic ash ingestion is primarily influenced by the fan at the front of the engine which produces the thrust that drives the aircraft. The ingested air is split between the core (compressor/combustor/turbine) and bypass (thrust) at a ratio of typically between, 1:5-10 on modern engines. Consequently, the ash particles are fractionated between the core and bypass by the geometry and dynamics of the fan blades. This study uses computational fluid dynamics (CFD) simulations of particle-laden airflows into a turbofan engine under different atmospheric and engine operation conditions. The main aim was to investigate the possible centrifugal effect of the fan blades as a function of particle size, and to relate this to the core intake concentration. We generated a generic 3D axial high-bypass turbofan engine using

  4. Lipid peroxidation and cytotoxicity induced by respirable volcanic ash.

    PubMed

    Cervini-Silva, Javiera; Antonio-Nieto-Camacho; Gomez-Vidales, Virginia; Ramirez-Apan, María Teresa; Palacios, Eduardo; Montoya, Ascención; Kaufhold, Stephan; Abidin, Zeanal; Theng, Benny K G

    2014-06-15

    This paper reports that the main component of respirable volcanic ash, allophane, induces lipid peroxidation (LP), the oxidative degradation of lipids in cell membranes, and cytotoxicity in murin monocyle/macrophage cells. Naturally-occurring allophane collected from New Zealand, Japan, and Ecuador was studied. The quantification of LP was conducted using the Thiobarbituric Acid Reactive Substances (TBARS) assay. The cytotoxic effect was determined by the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide colorimetric assay. Electron-Paramagnetic Resonance (EPR) determinations of naturally-occurring allophane confirmed the incorporation in the structure and clustering of structural Fe(3+), and nucleation and growth of small-sized Fe (oxyhydr)oxide or gibbsite. LP induced by allophane varied with time, and solid concentration and composition, reaching 6.7 ± 0.2 nmol TBARS mg prot(-1). LP was surface controlled but not restricted by structural or surface-bound Fe(3+), because redox processes induced by soluble components other than perferryl iron. The reactivity of Fe(3+) soluble species stemming from surface-bound Fe(3+) or small-sized Fe(3+) refractory minerals in allophane surpassed that of structural Fe(3+) located in tetrahedral or octahedral sites of phyllosilicates or bulk iron oxides. Desferrioxamine B mesylate salt (DFOB) or ethylenediaminetetraacetic acid (EDTA) inhibited LP. EDTA acted as a more effective inhibitor, explained by multiple electron transfer pathways. Registered cell-viability values were as low as 68.5 ± 6.7%.

  5. Volcanic Ashes Intercalated with Cultural Vestiges at Archaeological Sites from the Piedmont to the Amazon, Ecuador

    NASA Astrophysics Data System (ADS)

    Valverde, Viviana; Mothes, Patricia; Andrade, Daniel

    2014-05-01

    A mineralogical analysis was done on 70 volcanic ashes; 9 corresponding to proximal samples of seven volcanoes: Cotopaxi (4500 yBP), Guagua Pichincha (3300 yBP, 1000 yBP and 1660 yAD), Cuicocha (3100 yBP), Pululahua (2400 yBP), Ninahuilca (2350 yBP and 4600 yBP) and 61 to distal ashes collected at eight archaeological sites in the Coastal, Sierra and Amazon regions of Ecuador. Cultural vestiges are from Pre-ceramic, Formative, Regional Development and Integration periods, with the exception of a site denominated Hacienda Malqui, which also has Inca vestiges. The sampling process was done in collaboration with various archaeologists in 2011-2013. The volcanic ashes were washed, dried and divided in order to obtain a representative fraction and their later analysis with binocular microscope. The microscope analysis allowed determination of the characteristics of each component of volcanic ash. These main elements are: pumice fragments, minerals, volcanic glass, lithics and exogenous material (non volcanic). The petrographic analysis of distal volcanic ash layers at each archaeological site was correlated by their components and characteristics with proximal volcanic ashes of source volcanoes. Some correlations permitted obtaining a relative age for the layers of distal volcanic ash in the archaeological sites. The petrographic analysis showed a correlation between the archaeological sites of Las Mercedes - Los Naranjos, Rumipamba and El Condado (located west of Quito) with the eruptive activity of Guagua Pichincha volcano (3300 yBP, 1000 yBP and 1660 yAD) and Pululahua volcano (2400 yBP). Also, a correlation with eruptive activity of Ninahuilca (2350 yBP), Cotopaxi (4500 yBP) and Quilotoa (800 yBP) volcanoes at Hda. Malqui (60 km west of Latacunga) was provided by mineralogy of the respective ashes expulsed by these volcanoes. The ash layers at Cuyuja (50 km east of Quito) are mostly superficial; they are associated with Quilotoa's 800 yBP plinian. Finally at the

  6. Aerosol properties and meteorological conditions in the city of Buenos Aires, Argentina, during the resuspension of volcanic ash from the Puyehue-Cordón Caulle eruption

    NASA Astrophysics Data System (ADS)

    Graciela Ulke, Ana; Torres Brizuela, Marcela M.; Raga, Graciela B.; Baumgardner, Darrel

    2016-09-01

    The eruption in June 2011 of the Puyehue-Cordón Caulle Volcanic Complex in Chile impacted air traffic around the Southern Hemisphere for several months after the initial ash emissions. The ash deposited in vast areas of the Patagonian Steppe was subjected to the strong wind conditions prevalent during the austral winter and spring experiencing resuspension over various regions of Argentina. In this study we analyze the meteorological conditions that led to the episode of volcanic ash resuspension which impacted the city of Buenos Aires and resulted in the closure of the two main airports in Buenos Aires area (Ezeiza and Aeroparque) on 16 October 2011. A relevant result is that resuspended material (volcanic ash plus dust) imprints a distinguishable feature within the atmospheric thermodynamic vertical profiles. The thermodynamic soundings show the signature of "pulses of drying" in layers associated with the presence of hygroscopic ash in the atmosphere that has already been reported in similar episodes after volcanic eruptions in other parts of the world. This particular footprint can be used to detect the probable existence of volcanic ash layers. This study also illustrates the utility of ceilometers to detect not only cloud base at airports but also volcanic ash plumes at the boundary layer and up to 7 km altitude. Aerosol properties measured in the city during the resuspension episode indicate the presence of enhanced concentrations of aerosol particles in the boundary layer along with spectral signatures in the measurements at the Buenos Aires AERONET site typical of ash plus dust advected towards the city. The mandatory aviation reports from the National Weather Service about airborne and deposited volcanic ash at the airport near the measurement site (Aeroparque) correlate in time with the enhanced concentrations. The presence of the resuspended material was detected by the CALIOP lidar overpassing the region. Since the dynamics of ash resuspension and

  7. Controls on the surface chemical reactivity of volcanic ash investigated with probe gases

    NASA Astrophysics Data System (ADS)

    Maters, Elena C.; Delmelle, Pierre; Rossi, Michel J.; Ayris, Paul M.; Bernard, Alain

    2016-09-01

    Increasing recognition that volcanic ash emissions can have significant impacts on the natural and human environment calls for a better understanding of ash chemical reactivity as mediated by its surface characteristics. However, previous studies of ash surface properties have relied on techniques that lack the sensitivity required to adequately investigate them. Here we characterise at the molecular monolayer scale the surfaces of ash erupted from Eyjafjallajökull, Tungurahua, Pinatubo and Chaitén volcanoes. Interrogation of the ash with four probe gases, trimethylamine (TMA; N(CH3)3), trifluoroacetic acid (TFA; CF3COOH), hydroxylamine (HA; NH2OH) and ozone (O3), reveals the abundances of acid-base and redox sites on ash surfaces. Measurements on aluminosilicate glass powders, as compositional proxies for the primary constituent of volcanic ash, are also conducted. We attribute the greater proportion of acidic and oxidised sites on ash relative to glass surfaces, evidenced by comparison of TMA/TFA and HA/O3 uptake ratios, in part to ash interaction with volcanic gases and condensates (e.g., H2O, SO2, H2SO4, HCl, HF) during the eruption. The strong influence of ash surface processing in the eruption plume and/or cloud is further supported by particular abundances of oxidised and reduced sites on the ash samples resulting from specific characteristics of their eruptions of origin. Intense interaction with water vapour may result in a higher fraction of oxidised sites on ash produced by phreatomagmatic than by magmatic activity. This study constitutes the first quantification of ash chemical properties at the molecular monolayer scale, and is an important step towards better understanding the factors that govern the role of ash as a chemical agent within atmospheric, terrestrial, aquatic or biotic systems.

  8. Testing hypotheses for the use of Icelandic volcanic ashes as low cost, natural fertilizers

    NASA Astrophysics Data System (ADS)

    Seward, W.; Edwards, B.

    2012-04-01

    Andisols are soils derived from tephra/volcanic bedrock and are generally considered to be fertile for plant growth (cf. University of Hawaii at Manoa, CTAHR). However, few studies have been published examining the immediate effects of the addition of volcanic ash to soils immediately after an eruption. Our research is motivated by unpublished accounts from Icelandic farmers that the growing season following the 2010 Eyjafjallajökull eruption ended with unusually high yields in areas that were covered by ash from the eruption early in the spring. To test the hypothesis that addition of volcanic ash to soil would have no immediate effect on plant growth, we conducted a ~6 week growth experiment in at controlled environment at the Dickinson College Farm. The experiment used relatively fast growing grain seeds as a test crop, controlled watering, known quantities of peat as an organic base, and the following general experimental design: peat was mixed in known but systematically differing proportions with 1) commercial quartz sand, 2) basaltic ash from the 2004 Grimsvötn eruption, and 3) trachyandesite ash from the 2010 Eyjafjallajökull eruption. For all experiments, the seeds growing in the simulated soil created with the two different composition volcanic ash had higher germination rates, higher growth rates, and produced plants that were healthier in appearance than the soil made from peat mixed with quartz sand. Some differences were also noted between the germination and grow rates between the basaltic and trachyandesitic ash experiments as well. Working hypotheses to explain these results include (1) shard shapes and vesicles from volcanic ash provide better water retention than quartz, allowing water to be stored longer and increasing average soil moisture, and (2) chemical nutrients from the ash facilitate germination and growth of plants. Documenting the potential benefits of fresh volcanic ash as a fertilizer is important as use of fresh ash fertlizer

  9. Deposition and immersion mode nucleation of ice by three distinct samples of volcanic ash using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Schill, G. P.; Genareau, K.; Tolbert, M. A.

    2015-01-01

    Ice nucleation on volcanic ash controls both ash aggregation and cloud glaciation, which affect atmospheric transport and global climate. Previously, it has been suggested that there is one characteristic ice nucleation efficiency for all volcanic ash, regardless of its composition, when accounting for surface area; however, this claim is derived from data from only two volcanic eruptions. In this work, we have studied the depositional and immersion freezing efficiency of three distinct samples of volcanic ash using Raman Microscopy coupled to an environmental cell. Ash from the Fuego (basaltic ash, Guatemala), Soufrière Hills (andesitic ash, Montserrat), and Taupo (Oruanui euption, rhyolitic ash, New Zealand) volcanoes were chosen to represent different geographical locations and silica content. All ash samples were quantitatively analyzed for both percent crystallinity and mineralogy using X-ray diffraction. In the present study, we find that all three samples of volcanic ash are excellent depositional ice nuclei, nucleating ice from 225-235 K at ice saturation ratios of 1.05 ± 0.01, comparable to the mineral dust proxy kaolinite. Since depositional ice nucleation will be more important at colder temperatures, fine volcanic ash may represent a global source of cold-cloud ice nuclei. For immersion freezing relevant to mixed-phase clouds, however, only the Oruanui ash exhibited heterogeneous ice nucleation activity. Similar to recent studies on mineral dust, we suggest that the mineralogy of volcanic ash may dictate its ice nucleation activity in the immersion mode.

  10. Correlation and Analysis of Volcanic Ash in Marine Sediments From the Peru Margin

    NASA Astrophysics Data System (ADS)

    Hart, D.; Miller, J.

    2005-05-01

    While land studies have identified the major volcanic centers of historic eruptions and active to recent volcanism within the Central Volcanic Zone (CVZ) of the Central Andes, the tephrachronologic records are disturbed by the high erosion rates of this arid region. However, volcanic material frequently occurs in marine sediment as discrete ash-fall layers and, or disseminated ash accumulations. Cores from three Peru Margin sites sites(1227, 1228, and 1229) drilled during Ocean Drilling Program (ODP) Leg 201 have been studied to determine the occurrence of volcanic ash layers and ash accumulations within marine sediments along the Peru shelf. The thickness of each ash layer and accumulations has been measured and the volumes calculated in order to decipher the episodicity of explosive volcanic activity in the North-Central Andes recorded in the off shore sediments. The geographic distribution of the sites (over 3 degrees of latitude and from 50 to 300 km offshore) and correlation of ash units between sites form the basis for minimal estimates of explosive volcanic activity in the region (only eruptions large enough to deposit ash in excess of 100 km from source are represented). Pouclet et al., (1990) estimated the minimum explosive activity along the Andean Arc from ash-bearing sediments and ash layers within cores from sites along the Peru margin collected during ODP Leg 112. As a result of better recovery (as much as ten times more core recovery in many intervals) and decreased disturbance in cores recovered during Leg 201, our documentation of ash content in cores from Leg 201 has led to a more complete record of the explosive volcanic activity along the Andean Arc. For example, Pouclet, et al., (1990) reports four ash layers from Sites 684, 680, and 681, whereas forty ash layers have been documented from cores recovered from the same locations (Sites 1227, 1228, and 1229 respectively). Our stratigraphic record agrees with Pouclet, et al., (1990), suggesting

  11. “Breaking news” on the formation of volcanic ash: Fracture dynamics in silicate glass

    NASA Astrophysics Data System (ADS)

    Dürig, Tobias; Zimanowski, Bernd

    2012-06-01

    In explosive volcanic eruptions magmatic melts behave like brittle solids under rapid loading: volcanic ash particles predominantly are generated by brittle fragmentation, induced within pre-stressed magma in volcanic conduits. Here we present straightforward measurements of fracture area velocity, i.e., surface generation rates in analog materials under "volcanic" time— and deformation rates, using a high resolution high-speed camera at up to 2.5 million frames per second. Surface generation rates are directly linked to energy dissipation and can be related to pyroclast formation during explosive volcanism. According to our findings, pre-existing stress fields play a crucial role for the evolution of cracks, control the dynamics of fracture area growths during fragmentation, and thus strongly modify the production of volcanic ash.

  12. Effect of particle volume fraction on the settling velocity of volcanic ash particles: implications for ash dispersion models

    NASA Astrophysics Data System (ADS)

    Del Bello, E.; Taddeucci, J.; De'Michieli Vitturi, M.; Scarlato, P.; Andronico, D.; Scollo, S.; Kueppers, U.

    2015-12-01

    We present the first report of experimental measurements of the enhanced settling velocity of volcanic particles as function of particle volume fraction. In order to investigate the differences in the aerodynamic behavior of ash particles when settling individually or in mass, we performed systematic large-scale ash settling experiments using natural basaltic and phonolitic ash. By releasing ash particles at different, controlled volumetric flow rates, in an unconstrained open space and at minimal air movement, we measured their terminal velocity, size, and particle volume fraction with a high-speed camera at 2000 fps. Enhanced settling velocities of individual particles increase with increasing particle volume fraction. This suggests that particle clustering during fallout may be one reason explaining larger than theoretical depletion rates of fine particles from volcanic ash clouds. We provide a quantitative empirical model that allows to calculate, from a given particle size and density, the enhanced velocity resulting from a given particle volume fraction. The proposed model has the potential to serve as a simple tool for the prediction of the terminal velocity of ash of an hypothetical distribution of ash of known particle size and volume fraction. This is of particular importance for advection-diffusion transport model of ash where generally a one-way coupling is adopted, considering only the flow effects on particles. To better quantify the importance of the enhanced settling velocity in ash dispersal, we finally introduced the new formulation in a Lagrangian model calculating for realistic eruptive conditions the resulting ash concentration in the atmosphere and on the ground.

  13. A novel reactor for the simulation of gas and ash interactions in volcanic eruption plumes

    NASA Astrophysics Data System (ADS)

    Ayris, Paul M.; Cimarelli, Corrado; Delmelle, Pierre; Dingwell, Donald B.

    2014-05-01

    The chemical interactions between volcanic ash and the atmosphere, hydrosphere, pedosphere, cryosphere and biosphere are initially the result of rapid mobilisation of soluble salts and aqueous acids from wetted particle surfaces. Such surface features are attributable to the scavenging of sulphur and halide species by ash during its transport through the eruption plume and volcanic cloud. It has been historically considered (e.g., Rose, 1977) that the primary mechanism driving scavenging of sulphur and halide species is via condensation of acid aerosols onto ash surfaces within the cold volcanic cloud. However, for large explosive eruptions, insights from new experimental highlight the potential for scavenging via adsorption onto ash within the high-temperature eruption plume. In previous investigations on simple SO2 (Ayris et al. 2013a) and HCl systems (Ayris et al. 2013b), we identified ash composition, and the duration and temperature of gas-ash interaction as key determinants of adsorption-mode scavenging. However, the first generation of gas-ash reactors could not fully investigate the interactions between ash and the hydrous volcanic atmosphere; we have therefore developed an Advanced Gas Ash Reactor (AGAR), which can be fluxed with varying proportions of H2O, CO2, SO2 and HCl. The AGAR consists of a longitudinally-rotating quartz glass reaction bulb contained within a horizontal, three-stage tube furnace operating at temperatures of 25-900° C. A sample mass of up to 100 g can traverse a thermal gradient via manual repositioning of the reaction bulb within the furnace. In combination with existing melt synthesis capabilities in our laboratories, this facility permits a detailed investigation of the effects of ash and gas composition, and temperature on in-plume scavenging of SO2 and HCl. Additionally, the longitudinal rotation enables particle-particle interaction under an 'in-plume' atmosphere, and may yield insight into the effects of gas-ash interaction

  14. Combining four dimensional variational data assimilation and particle filtering for estimating volcanic ash emissions

    NASA Astrophysics Data System (ADS)

    Franke, Philipp; Elbern, Hendrik

    2016-04-01

    Estimating volcanic ash emissions is a very challenging task due to limited monitoring capacities of the ash plume and nonlinear processes in the atmosphere, which renders application of source strength and injection height estimations difficult. Most models, which estimate volcanic ash emissions, make strong simplifications of the dispersion of volcanic ash and corresponding atmospheric processes. The objective of this work is to estimate volcanic ash emissions and simulate the ensuing dispersion applying a full chemistry transport model in a hybrid approach by using its adjoint as well as an ensemble of model runs to quantify forecast uncertainties. Therefore, the four dimensional variational data assimilation version of the EURAD-IM chemistry transport model is extended to include a Sequential Importance Resampling Smoother (SIRS), introducing novel weighting and resampling strategies. In the main SIRS step the ensemble members exchange high rated emission patterns while rejecting emission patterns with low value for the forecast. The emission profiles of the ensemble members are perturbed afterwards to guarantee different emissions for all ensemble members. First identical twin experiments show the ability of the system to estimate the temporal and vertical distribution of volcanic ash emissions. The 4D-var data assimilation algorithm of the new system additionally provides quantitative emission estimation.

  15. Rapid releases of metal salts and nutrients following the deposition of volcanic ash into aqueous environments

    NASA Astrophysics Data System (ADS)

    Jones, Morgan T.; Gislason, Sigurður R.

    2008-08-01

    Deposition of volcanic ash into aqueous environments leads to dissolution of adsorbed metal salts and aerosols, increasing the bioavailability of key nutrients. Volcanogenic fertilization events could increase marine primary productivity, leading to a drawdown of atmospheric CO 2. Here we conduct flow-through experiments on unhydrated volcanic ash samples from a variety of locations and sources, measuring the concentrations and fluxes of elements into de-ionized water and two contrasting ocean surface waters. Comparisons of element fluxes show that dissolution of adsorbed surface salts and aerosols dominates over glass dissolution, even in sustained low pH conditions. These surface ash-leachates appear unstable, decaying in situ even if kept unhydrated. Volcanic ash from recent eruptions is shown to have a large fertilization potential in both fresh and saline water. Fluorine concentrations are integral to bulk dissolution rates and samples with high F concentrations display elevated fluxes of some nutrients, particularly Fe, Si, and P. Bio-limiting micronutrients are released in large quantities, suggesting that subsequent biological growth will be limited by macronutrient availability. Importantly, acidification of surface waters and high fluxes of toxic elements highlights the potential of volcanic ash-leachates to poison aqueous environments. In particular, large pH changes can cause undersaturation of CaCO 3 polymorphs, damaging populations of calcifying organisms. Deposition of volcanic ash can both fertilize and/or poison aqueous environments, causing significant changes to surface water chemistry and biogeochemical cycles.

  16. Selective preservation of carbohydrates in volcanic ash soils

    NASA Astrophysics Data System (ADS)

    Kaal, J.; Buurman, P.; Nierop, K. G. J.; Piccolo, A.

    2009-04-01

    Volcanic soils (Andosols) are formed in volcanic ash and depending on environmental and climatic factors they develop to two main forms, either allophanic Andosols (dominated by amorphous minerals) or non-allophanic Andosols (dominated by Al/Fe organic matter complexes). Andosols contain the largest amounts of organic carbon of all mineral soil orders. In recent studies using analytical pyrolysis techniques on the soil organic matter (SOM) of allophanic soils from the Azores Islands (Portugal) there was no indication of preservation of plant-derived organic matter by allophane or Al3+, but the presence of large amounts of (microbial) polysaccharides and chitin suggested that secondary organic matter products were stabilized. In the present study we used 13C NMR to further explore the organic matter of the Andosols of the Azores, and applied a molecular mixing model (MMM; ascribing characteristic resonances to the main biocomponent classes carbohydrate, protein, lipid, lignin and char) to the quantified NMR spectra to allow for a quantitative comparison with pyrolysis-GC/MS. The dominance of O-alkyl and di-O-alkyl C in the NMR spectra and carbohydrate contribution to the predictions made by the MMM (50 ± 8%) confirms that the majority of the SOM can still be recognised as carbohydrate. The accumulation of secondary/microbial carbohydrates (and, to a lesser extent, secondary proteinaceous matter and chitins) is thus a key characteristic of these Andosols. NMR-MMM and pyrolysis-GC/MS were in rough agreement. However, NMR does not recognise chitin (N-containing carbohydrate-like material) and chitin-associated protein, nor can it be used to estimate the degree of degradation of the carbohydrates. Therefore, NMR (as applied here) has a very limited capacity for characterisation of the SOM particularly in the Andosols studied. On the other hand, large peaks from carboxylic and amidic functional groups detected by NMR were not observed by pyrolysis-GC/MS. It is therefore

  17. APhoRISM FP7 project: the Multi-platform volcanic Ash Cloud Estimation (MACE) infrastructure

    NASA Astrophysics Data System (ADS)

    Merucci, Luca; Corradini, Stefano; Bignami, Christian; Stramondo, Salvatore

    2014-05-01

    APHORISM is an FP7 project that aims to develop innovative products to support the management and mitigation of the volcanic and the seismic crisis. Satellite and ground measurements will be managed in a novel manner to provide new and improved products in terms of accuracy and quality of information. The Multi-platform volcanic Ash Cloud Estimation (MACE) infrastructure will exploit the complementarity between geostationary, and polar satellite sensors and ground measurements to improve the ash detection and retrieval and to fully characterize the volcanic ash clouds from source to the atmosphere. The basic idea behind the proposed method consists to manage in a novel manner, the volcanic ash retrievals at the space-time scale of typical geostationary observations using both the polar satellite estimations and in-situ measurements. The typical ash thermal infrared (TIR) retrieval will be integrated by using a wider spectral range from visible (VIS) to microwave (MW) and the ash detection will be extended also in case of cloudy atmosphere or steam plumes. All the MACE ash products will be tested on three recent eruptions representative of different eruption styles in different clear or cloudy atmospheric conditions: Eyjafjallajokull (Iceland) 2010, Grimsvotn (Iceland) 2011 and Etna (Italy) 2011-2012. The MACE infrastructure will be suitable to be implemented in the next generation of ESA Sentinels satellite missions.

  18. Assimilating aircraft-based measurements to improve forecast accuracy of volcanic ash transport

    NASA Astrophysics Data System (ADS)

    Fu, G.; Lin, H. X.; Heemink, A. W.; Segers, A. J.; Lu, S.; Palsson, T.

    2015-08-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash transport forecast in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be run with Eruption Source Parameters (ESP) such as plume height and mass eruption rate as input, and with data assimilation techniques to continuously improve the initial conditions of the forecast. Reliable and accurate ash measurements are crucial for providing a successful ash clouds advice. In this paper, simulated aircraft-based measurements, as one type of volcanic ash measurements, will be assimilated into a transport model to identify the potential benefit of this kind of observations in an assimilation system. The results show assimilating aircraft-based measurements can significantly improve the state of ash clouds, and further providing an improved forecast as aviation advice. We also show that for advice of aeroplane flying level, aircraft-based measurements should be preferably taken from this level to obtain the best performance on it. Furthermore it is shown that in order to make an acceptable advice for aviation decision makers, accurate knowledge about uncertainties of ESPs and measurements is of great importance.

  19. Satellite Derived Volcanic Ash Product Inter-Comparison in Support to SCOPE-Nowcasting

    NASA Astrophysics Data System (ADS)

    Siddans, Richard; Thomas, Gareth; Pavolonis, Mike; Bojinski, Stephan

    2016-04-01

    In support of aeronautical meteorological services, WMO organized a satellite-based volcanic ash retrieval algorithm inter-comparison activity, to improve the consistency of quantitative volcanic ash products from satellites, under the Sustained, Coordinated Processing of Environmental Satellite Data for Nowcasting (SCOPEe Nowcasting) initiative (http:/ jwww.wmo.int/pagesjprogjsatjscopee nowcasting_en.php). The aims of the intercomparison were as follows: 1. Select cases (Sarychev Peak 2009, Eyjafyallajökull 2010, Grimsvötn 2011, Puyehue-Cordón Caulle 2011, Kirishimayama 2011, Kelut 2014), and quantify the differences between satellite-derived volcanic ash cloud properties derived from different techniques and sensors; 2. Establish a basic validation protocol for satellite-derived volcanic ash cloud properties; 3. Document the strengths and weaknesses of different remote sensing approaches as a function of satellite sensor; 4. Standardize the units and quality flags associated with volcanic cloud geophysical parameters; 5. Provide recommendations to Volcanic Ash Advisory Centers (VAACs) and other users on how to best to utilize quantitative satellite products in operations; 6. Create a "road map" for future volcanic ash related scientific developments and inter-comparison/validation activities that can also be applied to SO2 clouds and emergent volcanic clouds. Volcanic ash satellite remote sensing experts from operational and research organizations were encouraged to participate in the inter-comparison activity, to establish the plans for the inter-comparison and to submit data sets. RAL was contracted by EUMETSAT to perform a systematic inter-comparison of all submitted datasets and results were reported at the WMO International Volcanic Ash Inter-comparison Meeting to held on 29 June - 2 July 2015 in Madison, WI, USA (http:/ /cimss.ssec.wisc.edujmeetings/vol_ash14). 26 different data sets were submitted, from a range of passive imagers and spectrometers and

  20. El Chichon volcanic ash in the stratosphere - Particle abundances and size distributions after the 1982 eruption

    NASA Technical Reports Server (NTRS)

    Gooding, J. L.; Clanton, U. S.; Gabel, E. M.; Warren, J. L.

    1983-01-01

    Volcanic ash particles collected from the stratosphere after the March/April, 1982 explosive eruption of El Chichon volcano, Mexico, were mostly 2-40 micron vesicular shards of silicic volcanic glass that varied in abundance, at 16.8-19.2 km altitude, from 200 per cu m (30-49 deg N lat.) in May to 1.3 per cu m (45-75 deg N) in October. At the minimum, the ash cloud covered latitudes 10-60 deg N in July and 10 deg S-75 deg N in October. In May and July, ash particles were mostly free, individual shards (and clusters of shards) but, by October, were intimately associated with liquid droplets (presumably, sulfuric acid). In May 1982, the total stratospheric burden of ash was at least 240 tons (2.2 x 10 to the 8th g) although the total ash injected into the stratosphere by the eruption was probably 480-8400 tons.

  1. Volcanic Ash fall Impact on Vegetation, Colima 2005

    NASA Astrophysics Data System (ADS)

    Garcia, M. G.; Martin, A.; Fonseca, R.; Nieto, A.; Radillo, R.; Armienta, M.

    2007-05-01

    An ash sampling network was established arround Colima Volcano in 2005. Ash fall was sampled on the North, Northeast, East, Southeast, South, Southwest and West of the volcano. Samples were analyzed for ash components, geochemistry and leachates. Ash fall ocurred on April (12), May (10, 23), June (2, 6, 9, 10, 12, 14), July (27), September (27), October (23) and November (24). Most of the ash is made of andesitic dome-lithics but shows diferences in crystal, juvenile material and lithic content. In May, some samples contained grey and dark pumice (scoria). Texture varies from phi >4 to phi 0. Leachate concentration were low: SO4 (7.33-54.19) Cl- (2.29-4.97) and F- (0.16-0.37). During 2005, Colima Volcano's ash fall rotted some of the guava and peach fruits and had a drying effect on spearment and epazote plants. Even these small ash amounts could have hindered sugar cane and agave growth.

  2. Volcanic ash aggregation in the lab - can we mimic natural processes?

    NASA Astrophysics Data System (ADS)

    Mueller, Sebastian B.; Kueppers, Ulrich; Jacob, Michael; Ayris, Paul; Cimarelli, Corrado; Dingwell, Donald B.; Guttzeit, Melanie; Hess, Kai-Uwe; Walter, Ulrich

    2015-04-01

    Explosive volcanic eruptions release large amounts of particles into the atmosphere. Volcanic ash, by definition pyroclasts smaller than 2 mm, can be distributed around the globe by prevailing winds. Ash poses hazards to aviation industry by melting in jet turbines, to human health by entering respiration systems and to society by damaging infrastructure. Under certain circumstances, ash particles can cluster together and build ash aggregates. Aggregates range in size from few mm to few cm and may exhibit complex internal stratigraphy. During growth, weight, density and aerodynamic properties change, leading to a significantly different settling behavior compared to individual ash particles. Although ash aggregation has been frequently observed in the geologic record, the physical and chemical mechanisms generating the aggregates remain poorly understood. During several field campaigns, we collected numerous ash aggregates and analyzed their textural, chemical and mechanical properties. Based on this knowledge, we have designed experiments using the ProCell Lab System® of Glatt Ingenieurtechnik GmbH, Germany. In this device, a continuous fluidized bed can be applied on solid particles and simulate gas-particle flow conditions as they would be expected in volcanic plumes or pyroclastic density currents. The geological record and direct observations have shown that both processes are capable of producing ash aggregates. As starting material we used Na-glass beads as an analogue and volcanic ash from Laacher See Volcano, Eifel Volcanic Field, Germany. We define parameters such as grainsize, specific surface area and concentration of the starting material, degree of turbulence, temperature and moisture in the process chamber and the composition of the liquid phase to influence form, size, stability and production rate of aggregates. We were able to experimentally produce round, unstructured ash pellets up to 5mm in diameter. A detailed textural description highlights

  3. Calibration of microbolometer infrared cameras for measuring volcanic ash mass loading

    NASA Astrophysics Data System (ADS)

    Carroll, Russell C.

    Small spacecraft with thermal infrared (TIR) imaging capabilities are needed to detect dangerous levels of volcanic ash that can severely damage jet aircraft engines and must be avoided. Grounding aircraft after a volcanic eruption may cost the airlines millions of dollars per day, while accurate knowledge of volcanic ash density might allow for safely routing aircraft around dangerous levels of volcanic ash. There are currently limited numbers of satellites with TIR imaging capabilities so the elapsed time between revisits can be large, and these instruments can only resolve total mass loading along the line-of-sight. Multiple small satellites could allow for decreased revisit times as well as multiple viewing angles to reveal the three-dimensional structure of the ash cloud through stereoscopic techniques. This paper presents the design and laboratory evaluation of a TIR imaging system that is designed to fit within the resource constraints of a multi-unit CubeSat to detect volcanic ash mass loading. The laboratory prototype of this TIR imaging system uses a commercial off-the shelf (COTS) camera with an uncooled microbolometer sensor, two narrowband filters, a black body source and a custom filter wheel. The infrared imaging system detects the difference in attenuation of volcanic ash at 11 mum and 12 mum by measuring the brightness temperature at each band. The brightness temperature difference method is used to measure the column mass loading. Multi-aspect images and stereoscopic techniques are needed to estimate the mass density from the mass loading, which is the measured mass per unit area. Laboratory measurements are used to characterize the noise level and thermal stability of the sensor. A calibration technique is developed to compensate for sensor temperature drift. The detection threshold of volcanic ash density of this TIR imaging system is found to be from 0.35 mg/m3 to 26 mg/m3 for ash clouds that have thickness of 1 km, while ash cloud densities

  4. Chemistry of ash-leachates: a reliable monitoring tool for volcanic activity

    NASA Astrophysics Data System (ADS)

    Armienta, M. A.; De la Cruz-Reyna, S.; Soler, A.; Ceniceros, N.; Cruz, O.; Aguayo, A.

    2012-04-01

    Real-time volcanic hazard assessment requires the integrated interpretation of data obtained with different monitoring methods, particularly when people may be at risk. One of the methods rendering earliest precursory variations reflecting the internal state of a volcano is the geochemical analysis of gases, ground or lake waters related to volcanic systems, and volcanic ash. At Popocatépetl volcano, Central México, chemical fluctuations of the soluble cover of volcanic ash particles has proved to reflect diverse characteristics of the eruption types. Chloride, sulfate and fluoride concentrations of ash leachates have been consistently measured within the current eruptive episode beginning in December 1994. Particularly, main anions presented diverse relative concentrations in periods of dome extrusions, contrasting with hydrothermal activity or quiescence. Multivariate statistical analysis revealed that higher proportions of fluoride in the leachates corresponded to new dome emplacements and relatively higher sulfate concentrations to hydrothermal ashes, although these results may be ambiguous at times. However, different sulfur isotopic ratios were measured in sulfate from ashes erupted during periods dominated by hydrothermal activity to those emitted during dome emplacement. Additionally, ascent of fresh magma was reflected on high fluoride concentrations jointly with low 34S-SO4 isotopic values. It is thus recommended to maintain persistent analyses of ash-leachates from on-going eruptions as a monitoring tool at active volcanoes.

  5. Eyjafjallajokull volcanic ash concentrations determined from CALIOP and SEVIRI measurements (Invited)

    NASA Astrophysics Data System (ADS)

    Prata, F.; Prata, A.

    2010-12-01

    During 14 April to 25 May 2010, Eyjfjoll volcano in Iceland, erupted a large amount of fine grained ash that rapidly spread across the north Atlantic and entered European airspace causing significant disruption to commercial aviation. Dispersion models and satellite data were used to identify the location of the Eyjafloll ash cloud, but due to lack of information on the eruption source parameters, quantitative estimates of the ash concentrations could not be made. By using multispectral, high frequency geosynchronous satellite measurements from the SEVIRI instrument, it is shown that quantitative estimates of the mass loadings (g m-2) can be made with accuracies of ±50% and with a detection limit of ~0.5 g m-2, every 15 minutes (night or day) and with a spatial resolution that varies from about 10--100 km2, depending on scan position. When the mass loadings are combined with coincident cloud thickness measurements from the Caliop lidar on board CALIPSO, ash concentrations can be derived. Here it is shown that ash concentrations in the dense parts of the dispersing Eyjfjoll ash cloud frequently exceeded 4 mg m-3 and that ash clouds with concentrations >2 mg m-3 covered large parts of European airspace on several occasions. Animated loops of SEVIRI ash mass loadings have been generated and a Google Earth applet designed to illustrate the geographic extent of the ash over Europe, and interactively interrogate the retrievals. Air-routes from European and US airports can also be added. These tools and the new satellite retrieval methodology may be combined with dispersion model results to provide Volcanic Ash Advisory Centres (VAACs) with better information for issuing volcanic ash advisories Google Earth visualization showing SEVIRI retrieved ash mass loadings and air routes from London to airports in Ireland, Scotland and continental Europe that cross the hazardous ash cloud.

  6. D Visualization of Volcanic Ash Dispersion Prediction with Spatial Information Open Platform in Korea

    NASA Astrophysics Data System (ADS)

    Youn, J.; Kim, T.

    2016-06-01

    Visualization of disaster dispersion prediction enables decision makers and civilian to prepare disaster and to reduce the damage by showing the realistic simulation results. With advances of GIS technology and the theory of volcanic disaster prediction algorithm, the predicted disaster dispersions are displayed in spatial information. However, most of volcanic ash dispersion predictions are displayed in 2D. 2D visualization has a limitation to understand the realistic dispersion prediction since its height could be presented only by colour. Especially for volcanic ash, 3D visualization of dispersion prediction is essential since it could bring out big aircraft accident. In this paper, we deals with 3D visualization techniques of volcanic ash dispersion prediction with spatial information open platform in Korea. First, time-series volcanic ash 3D position and concentrations are calculated with WRF (Weather Research and Forecasting) model and Modified Fall3D algorithm. For 3D visualization, we propose three techniques; those are 'Cube in the air', 'Cube in the cube', and 'Semi-transparent plane in the air' methods. In the 'Cube in the Air', which locates the semitransparent cubes having different color depends on its particle concentration. Big cube is not realistic when it is zoomed. Therefore, cube is divided into small cube with Octree algorithm. That is 'Cube in the Cube' algorithm. For more realistic visualization, we apply 'Semi-transparent Volcanic Ash Plane' which shows the ash as fog. The results are displayed in the 'V-world' which is a spatial information open platform implemented by Korean government. Proposed techniques were adopted in Volcanic Disaster Response System implemented by Korean Ministry of Public Safety and Security.

  7. Online-coupled modeling of volcanic ash and SO2 dispersion with WRF-Chem

    NASA Astrophysics Data System (ADS)

    Stuefer, Martin; Egan, Sean; Webley, Peter; Grell, Georg; Freitas, Saulo; Pavolonis, Mike; Dehn, Jonathan

    2014-05-01

    We included a volcanic emission and plume model into the Weather Research Forecast Model with inline Chemistry (WRF-Chem). The volcanic emission model with WRF-Chem has been tested and evaluated with historic eruptions, and the volcanic application was included into the official release of WRF-Chem beginning with WRF version 3.3 in 2011. Operational volcanic WRF-Chem runs have been developed using different domains centered on main volcanoes of the Aleutian chain and Popocatépetl Volcano, Mexico. The Global Forecast System (GFS) is used for the meteorological initialization of WRF-Chem, and default eruption source parameters serve as initial source data for the runs. We report on the model setup, and the advantages to treat the volcanic ash and sulphur dioxide emissions inline within the numerical weather prediction model. In addition we outline possibilities to initialize WRF-Chem with a fully automated algorithm to retrieve volcanic ash cloud properties from satellite data. WRF-Chem runs from recent volcanic eruptions resulted in atmospheric ash loadings, which compared well with the satellite data taking into account that satellite retrieval data represent only a limited amount of the actually emitted source due to detection thresholds. In addition particle aggregative effects are not included in the WRF-Chem model to date.

  8. Comments on "Failures in detecting volcanic ash from a satellite-based technique"

    USGS Publications Warehouse

    Prata, F.; Bluth, G.; Rose, B.; Schneider, D.; Tupper, A.

    2001-01-01

    The recent paper by Simpson et al. [Remote Sens. Environ. 72 (2000) 191.] on failures to detect volcanic ash using the 'reverse' absorption technique provides a timely reminder of the danger that volcanic ash presents to aviation and the urgent need for some form of effective remote detection. The paper unfortunately suffers from a fundamental flaw in its methodology and numerous errors of fact and interpretation. For the moment, the 'reverse' absorption technique provides the best means for discriminating volcanic ash clouds from meteorological clouds. The purpose of our comment is not to defend any particular algorithm; rather, we point out some problems with Simpson et al.'s analysis and re-state the conditions under which the 'reverse' absorption algorithm is likely to succeed. ?? 2001 Elsevier Science Inc. All rights reserved.

  9. Estimation of volcanic ash emission profiles using ceilometer measurements and transport models

    NASA Astrophysics Data System (ADS)

    Chan, Ka Lok; Geiß, Alexander; Gasteiger, Josef; Wagner, Frank; Wiegner, Matthias

    2016-04-01

    In recent years, the number of active remote sensing systems grows rapidly, since several national weather services initiated ceilometer networks. These networks are excellent tools to monitor the dispersion of volcanic ash clouds and to validate chemical transport models. Moreover, it is expected that the can be used to refine model calculations to better predict situations that might be dangerous for aviation. As a ceilometer can be considered as a simple single-wavelength backscatter lidar, quantitative aerosol profile information, i.e., the aerosol backscatter coefficient (βp) profile, can be derived provided that the ceilometer is calibrated. Volcanic ash concentration profile can then be estimated by using prior optical properties of volcanic ash. These profiles are then used for the inverse calculation of the emission profile of the volcanic eruption, thus, improving one of the most critical parameters of the numerical simulation. In this study, the Lagrangian particle dispersion model FLEXPART (FLEXible PARTicle dispersion model) is used to simulate the dispersion of volcanic ash. We simulate the distribution of ash for a given time/height grid, in order to compute the sensitivity functions for each measurements. As an example we use ceilometer measurements of the German weather service to reconstruct the temporal and spatial emission profile of Eyjafjallajökull eruption in April 2010. We have also examined the sensitivity of the retrieved emission profiles to different measurement parameters, e.g., geolocation of the measurement sites, total number of measurement sites, temporal and vertical resolution of the measurements, etc. The first results show that ceilometer measurements in principle are feasible for the inversion of volcanic ash emission profiles.

  10. Signal to Noise Ratio Estimations for a Volcanic ASH Detection Lidar. Case Study: The Met Office

    NASA Astrophysics Data System (ADS)

    Georgoussis, George; Adam, Mariana; Avdikos, George

    2016-06-01

    In this paper we calculate the Signal-to-Noise (SNR) ratio of a 3-channel commercial (Raymetics) volcanic ash detection system, (LR111-D300), already operating under Met Office organization. The methodology for the accurate estimation is presented for day and nighttime conditions. The results show that SNR values are higher than 10 for ranges up to 13 km for both nighttime and daytime conditions. This is a quite good result compared with other values presented in bibliography and proves that such system is able to detect volcanic ash over a range of 20 km.

  11. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

    PubMed

    Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P; Rohling, Eelco J; Satow, Chris; Smith, Victoria C; Stringer, Chris B; Tomlinson, Emma L; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Boric, Dusan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C

    2012-08-21

    Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters. PMID:22826222

  12. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards

    PubMed Central

    Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L.; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S.; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P.; Rohling, Eelco J.; Satow, Chris; Smith, Victoria C.; Stringer, Chris B.; Tomlinson, Emma L.; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Borić, Dušan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C.; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C.

    2012-01-01

    Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters. PMID:22826222

  13. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards.

    PubMed

    Lowe, John; Barton, Nick; Blockley, Simon; Ramsey, Christopher Bronk; Cullen, Victoria L; Davies, William; Gamble, Clive; Grant, Katharine; Hardiman, Mark; Housley, Rupert; Lane, Christine S; Lee, Sharen; Lewis, Mark; MacLeod, Alison; Menzies, Martin; Müller, Wolfgang; Pollard, Mark; Price, Catherine; Roberts, Andrew P; Rohling, Eelco J; Satow, Chris; Smith, Victoria C; Stringer, Chris B; Tomlinson, Emma L; White, Dustin; Albert, Paul; Arienzo, Ilenia; Barker, Graeme; Boric, Dusan; Carandente, Antonio; Civetta, Lucia; Ferrier, Catherine; Guadelli, Jean-Luc; Karkanas, Panagiotis; Koumouzelis, Margarita; Müller, Ulrich C; Orsi, Giovanni; Pross, Jörg; Rosi, Mauro; Shalamanov-Korobar, Ljiljiana; Sirakov, Nikolay; Tzedakis, Polychronis C

    2012-08-21

    Marked changes in human dispersal and development during the Middle to Upper Paleolithic transition have been attributed to massive volcanic eruption and/or severe climatic deterioration. We test this concept using records of volcanic ash layers of the Campanian Ignimbrite eruption dated to ca. 40,000 y ago (40 ka B.P.). The distribution of the Campanian Ignimbrite has been enhanced by the discovery of cryptotephra deposits (volcanic ash layers that are not visible to the naked eye) in archaeological cave sequences. They enable us to synchronize archaeological and paleoclimatic records through the period of transition from Neanderthal to the earliest anatomically modern human populations in Europe. Our results confirm that the combined effects of a major volcanic eruption and severe climatic cooling failed to have lasting impacts on Neanderthals or early modern humans in Europe. We infer that modern humans proved a greater competitive threat to indigenous populations than natural disasters.

  14. Optical, microphysical and compositional properties of the Eyjafjallajökull volcanic ash

    NASA Astrophysics Data System (ADS)

    Rocha-Lima, A.; Martins, J. V.; Remer, L. A.; Krotkov, N. A.; Tabacniks, M. H.; Ben-Ami, Y.; Artaxo, P.

    2014-05-01

    Microphysical, optical, and compositional properties of the volcanic ash from the April-May (2010) Eyjafjallajökull volcanic eruption are presented. Samples of the volcanic ash were taken on the ground in the vicinity of the volcano. The material was sieved, re-suspended, and collected on filters, separating particle sizes into coarse and fine modes. The spectral mass absorption efficiency αabs [m2 g-1] was determined for coarse and fine particles in the wavelength range from 300 to 2500 nm. Size distribution of particles on filters was obtained using a semi-automatic software to analyze images obtained by Scanning Electron Microscopy (SEM). The grain density of the volcanic ash was determined as 2.16(13) g cm-3 by measuring the variation of air volume in a system with volcanic ash and air under compression. Using Mie-Lorenz and T-matrix theories, the imaginary part of the refractive index was derived. Results show the spectral imaginary refractive index ranging from 0.001 to 0.005. Fine and coarse particles were analyzed by X-Ray fluorescence for elemental composition. Fine and coarse mode particles exhibit distinct compositional and optical differences.

  15. A multifrequency laboratory investigation of attenuation and scattering from volcanic ash clouds

    SciTech Connect

    Bredow, J.W.; Porco, R.; Dawson, M.S.; Betty, C.L.; Self, S.; Thordarson, T.

    1995-07-01

    Interest in remote monitoring of volcanic activity has increased in the last several years partly as a result of several powerful eruptions and partly as a result of satellite-borne spectrometers with thermal IR bands with which to monitor the physical makeup and effects of the volcanic inputs to the atmosphere. In this paper, the authors consider the first wide-bandwidth laboratory experiments intended to improve the understanding of the spectral response of volcanic ash important for remote sensing of volcano eruption ejecta, making comparison between data from the laboratory of ash suspensions and Mie theory for scattering and attenuation from spheres. Described are the experimental configuration, the sample preparation technique and the results obtained. The results indicate a general spherelike behavior of the ash, however the levels indicate effective radii that lie at the extremes of the actual particle size ranges. The data presented here are unique in their multispectral character as well as their control over ash particle size distributions. They should be useful in the process of selecting appropriate remote sensing datasets and for improving models for retrieving estimates of particle size distribution, concentration, total mass of ash ejected, cloud drift, and fall-out rate from that data. They should also be useful for designing and assessing performance of ash hazard sensors for flying aircraft.

  16. Leachability of uranium and other elements from freshly erupted volcanic ash

    USGS Publications Warehouse

    Smith, D.B.; Zielinski, R.A.; Rose, W.I.

    1982-01-01

    A study of leaching of freshly erupted basaltic and dacitic air-fall ash and bomb fragment samples, unaffected by rain, shows that glass dissolution is the dominant process by which uranium is initially mobilized from air-fall volcanic ash. Si, Li, and V are also preferentially mobilized by glass dissolution. Gaseous transfer followed by fixation of soluble uranium species on volcanic-ash particles is not an important process affecting uranium mobility. Gaseous transfer, however, may be important in forming water-soluble phases, adsorbed to ash surfaces, enriched in the economically and environmentally important elements Zn, Cu, Cd, Pb, B, F, and Ba. Quick removal of these adsorbed elements by the first exposure of freshly erupted ash to rain and surface water may pose short-term hazards to certain forms of aquatic and terrestrial life. Such rapid release of material may also represent the first step in transportation of economically important elements to environments favorable for precipitation into deposits of commercial interest. Ash samples collected from the active Guatemalan volcanoes Fuego and Pacaya (high-Al basalts) and Santiaguito (hornblende-hypersthene dacite); bomb fragments from Augustine volcano (andesite-dacite), Alaska, and Heimaey (basalt), Vestmann Islands, Iceland; and fragments of "rhyolitic" pumice from various historic eruptions were subjected to three successive leaches with a constant water-to-ash weight ratio of 4:1. The volcanic material was successively leached by: (1) distilled-deionized water (pH = 5.0-5.5) at room temperature for 24 h, which removes water-soluble gases and salts adsorbed on ash surfaces during eruption; (2) dilute HCl solution (pH = 3.5-4.0) at room temperature for 24 h, which continues the attack initiated by the water and also attacks acid-soluble sulfides and oxides; (3) a solution 0.05 M in both Na,CO, and NaHCO, (pH = 9.9) at 80°C for one week, which preferentially dissolves volcanic glass. The first two leaches

  17. Volcanic ash detection and retrievals from MODIS data by means of Neural Networks

    NASA Astrophysics Data System (ADS)

    Picchiani, M.; Chini, M.; Corradini, S.; Merucci, L.; Sellitto, P.; Del Frate, F.; Stramondo, S.

    2011-05-01

    Volcanic ash clouds detection and retrieval represent a key issue for the aviation safety due to the harming effects they can provoke on aircrafts. A lesson learned from the recent Icelandic Eyjafjalla volcano eruption is the need to obtain accurate and reliable retrievals on a real time basis. The current most widely adopted procedures for ash detection and retrieval are based on the Brightness Temperature Difference (BTD) inversion observed at 11 and 12 μm that allows volcanic and meteo clouds discrimination. While ash cloud detection can be readily obtained, a reliable quantitative ash cloud retrieval can be so time consuming to prevent its utilization during the crisis phase. In this work a fast and accurate Neural Network (NN) approach to detect and retrieve volcanic ash cloud properties has been developed using multispectral IR measurements collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) over Mt. Etna volcano during 2001, 2002 and 2006 eruptive events. The procedure consists in two separate steps: the ash detection and ash mass retrieval. The detection is reduced to a classification problem by identifying two classes of "ashy" and "non-ashy" pixels in the MODIS images. Then the ash mass is estimated by means of the NN, replicating the BTD-based model performances. The results obtained from the entire procedure are very encouraging; indeed the confusion matrix for the test set has an accuracy greater than 90 %. Both ash detection and retrieval show a good agreement when compared to the results achieved by the BTD-based procedure. Moreover, the NN procedure is so fast to be extremely attractive in all the cases when the quick response time of the system is a mandatory requirement.

  18. Soil and geomorphic evolution within the rolling red plains using pleistocene volcanic ash deposits

    NASA Astrophysics Data System (ADS)

    Carter, Brian J.; Ward, Phil A.; Shannon, Jean T.

    1990-09-01

    Pleistocene volcanic ash deposits are found within alluvium from the Arkansas river south to the Brazos river. This drainage area includes tributaries originating in the High Plains, the Raton volcanic field and the Rocky Mountain Front Range within the states of Colorado, New Mexico, Kansas, Texas, and Oklahoma. Thirteen ash deposits are dated from within the High Plains of Kansas and Texas eastward into central Oklahoma to understand the geomorphic history and improve soil and geologic mapping. Within the study area unsolidated Tertiary and Quaternary sediments deposited in a west to east direction overlie Triassic, Permian, and Pennsylvanian bedrock. Volcanic ash deposits are predominantly Early to Middle Pleistocene age. Volcanic ash deposits were dated by the fission track method on shards. The ash deposits are contained within four land resource regions, the Southern and Central High Plains, the High Plains Breaks, the Rolling Red Plains, and the Reddish Prairies. Extensive Middle Pleistocene constructional stream terrace surfaces occur within the Rolling Red Plains. Multiple stream terrace surfaces were recognized across the study area with the highest level being dated Early Pleistocene to Pliocene and the lowest bordering the Holocene floodplains. Topographic cross-sections (100 km long at 1:24,000 scale) transecting dated ash deposits and perpendicular to major river systems were used to distinguish terrace levels. Constructional terrace surfaces dated by ash deposits range from 21 to 100 m above and 1 to 16 km distance from present river channels. Soil orders formed in Quaternary alluvium are Entisols, Inceptisols, Mollisols, Alfisols and Vertisols. Ustic and udic soil moisture regimes and a thermic (15 to 22°C mean annual temperature) soil temperature regime dominate the study area. The same soil series is often mapped on terrace surfaces spanning Early to Middle Pleistocene age because current classification does not recognize differences in deeply

  19. What Controls the Sizes and Shapes of Volcanic Ash? Integrating Morphological, Textural and Geochemical Ash Properties to Decipher Eruptive Processes

    NASA Astrophysics Data System (ADS)

    Liu, E. J.; Cashman, K. V.; Rust, A.

    2015-12-01

    Volcanic ash particles encompass a diverse spectrum of shapes as a consequence of differences in the magma properties and the magma ascent and eruption conditions. We show how the quantitative analysis of ash particle shapes can be a valuable tool for deciphering magma fragmentation and transport processes. Importantly, integrating morphological data with ash texture (e.g. bubble and crystal sizes) and dissolved volatile data provides valuable insights into the physical and chemical controls on the resulting ash deposit. To explore the influence of magma-water interaction (MWI) on fine ash generation, we apply this multi-component characterisation to tephra from the 2500BC Hverfjall Fires, Iceland. Here, coeval fissure vents spanned sub-aerial to shallow lacustrine environments. Differences in the size and morphology of pyroclasts thus reflect fragmentation mechanisms under different near-surface conditions. Using shape parameters sensitive to both particle roughness and internal vesicularity, we quantify the relative proportions of dense fragments, bubble shards, and vesicular grains from 2-D SEM images. We show that componentry (and particle morphology) varies as a function of grain size, and that this variation can be related back to the bubble size distribution. Although both magmatic and hydromagmatic deposits exhibit similar component assemblages, they differ in how these assemblages change with grain size. These results highlight the benefits of characterising ash deposits over a wide range of grain sizes, and caution against inferring fragmentation mechanism from a narrow grain size range. Elevated matrix glass S concentrations in hydromagmatic ash (600-1500 ppm) compared to those in magmatic ash and scoria lapilli (200-500 ppm) indicate interrupted vesiculation. In contrast to the subaerial 'dry' deposits, fragmentation during MWI likely occurred over a greater range of depths with quench rates sufficient to prevent post-fragmentation degassing. High

  20. Understanding and Quantifying the Uncertainties of Volcanic Ash Emission Retrievals in Near Real Time Operations

    NASA Astrophysics Data System (ADS)

    Steensen, T. S.; Webley, P.; Dehn, J.

    2013-12-01

    Quantifying volcanic ash emissions syn-eruptively is an important task for the global aviation community. However, due to the near real time nature of volcano monitoring, many parameters important for accurate ash mass estimates cannot be obtained easily. Previous studies highlight the surface temperature, the refractive index of the ash and the cloud top temperature as most crucial of these values. The study presented here shows the effects that a pixel-based surface temperature has on the derived ash masses when compared to a generic value applied for all pixels and all time steps. Our findings show that the variability in the ash masses can be considerably larger with a universal surface temperature but the ash masses in general can be lower than those calculated using a pixel-based value. Still, the uncertainties associated with the ash masses remain high, especially when the satellite data is only available in the traditional 10.8 and 12.0 μm bands. To counteract this limitation, we developed a quantitative comparison between the ash extents in satellite and model data. The main aspect is to manually define the cloud edge based on the available satellite data as well as other knowledge like pilot reports or ground-based observations. This manual aspect, although subjective to the experience of the observer, can show a significant improvement as it provides the ability to highlight ash that otherwise would be obscured by meteorological clouds or, by passing over different surfaces with unaccounted temperatures, might be lost entirely and thus remains undetectable for an automated satellite approach. We show comparisons to Volcanic Ash Transport and Dispersion models and outline a quantitative match as well as percentages of overestimates based on satellite or model data which can be converted into a level of reliability for near real time volcano monitoring.

  1. The Persistence of Volcanic Ash in the Tropical Stratosphere after the Kelud Eruption

    NASA Astrophysics Data System (ADS)

    Vernier, J. P.; Fairlie, T. D.; Deshler, T.; Knepp, T. N.; Natarajan, M.; Foster, K.; Trepte, C. R.; Thomason, L. W.; Bedka, K. M.; Wienhold, F.

    2014-12-01

    An increase of volcanic activity over the past decade is thought to have contributed significantly to the global warming "hiatus". Thus, it is important to improve our understanding of the microphysical and optical properties of even small volcanic plumes as well as their associated climate impacts. On February 13th, 2014, the Mt Kelud volcano, located near 4°S on the island of Java (Indonesia), injected volcanic gases and ash into the tropical stratosphere. An overpass of the CALIPSO lidar during the active phase of the eruption showed volcanic materials reaching 26 km with the main volcanic cloud near 18-19 km. This is the highest altitude volcanic injection since Mt Pinatubo in 1991. CALIPSO has tracked the dispersion of the Kelud plume throughout the tropical lower stratosphere (~20N-20S) since then. Depolarization lidar measurements (0.3-0.4) indicate that the plume was likely composed of irregularly shaped ash particles during the first few days after the eruption, and that sulfate aerosol (spherical droplets) formed thereafter, gradually lowering the mean depolarization to 0.1-0.2. In May, 2014, we mounted a 2-week campaign to Darwin (Australia) to measure several profiles of backscatter in red and blue channels, and one profile of aerosol size distribution using two optical particle counters, one with an inlet heated to 200°C. The purpose was to characterize particle sizes, optical properties, and sulfate fraction from a relatively fresh volcanic plume in the low stratosphere. Preliminary results from the campaign suggest the persistence of ash particles at the bottom of the Kelud plume 3 months after the eruption. This is significant because the climate impact of ash is neglected in most climate models.

  2. Effects of Eyjafjallajökull Volcanic Ash on Innate Immune System Responses and Bacterial Growth in Vitro

    PubMed Central

    Baltrusaitis, Jonas; Powers, Linda S.; Borcherding, Jennifer A.; Caraballo, Juan C.; Mudunkotuwa, Imali; Peate, David W.; Walters, Katherine; Thompson, Jay M.; Grassian, Vicki H.; Gudmundsson, Gunnar; Comellas, Alejandro P.

    2013-01-01

    Background: On 20 March 2010, the Icelandic volcano Eyjafjallajökull erupted for the first time in 190 years. Despite many epidemiological reports showing effects of volcanic ash on the respiratory system, there are limited data evaluating cellular mechanisms involved in the response to ash. Epidemiological studies have observed an increase in respiratory infections in subjects and populations exposed to volcanic eruptions. Methods: We physicochemically characterized volcanic ash, finding various sizes of particles, as well as the presence of several transition metals, including iron. We examined the effect of Eyjafjallajökull ash on primary rat alveolar epithelial cells and human airway epithelial cells (20–100 µg/cm2), primary rat and human alveolar macrophages (5–20 µg/cm2), and Pseudomonas aeruginosa (PAO1) growth (3 µg/104 bacteria). Results: Volcanic ash had minimal effect on alveolar and airway epithelial cell integrity. In alveolar macrophages, volcanic ash disrupted pathogen-killing and inflammatory responses. In in vitro bacterial growth models, volcanic ash increased bacterial replication and decreased bacterial killing by antimicrobial peptides. Conclusions: These results provide potential biological plausibility for epidemiological data that show an association between air pollution exposure and the development of respiratory infections. These data suggest that volcanic ash exposure, while not seriously compromising lung cell function, may be able to impair innate immunity responses in exposed individuals. PMID:23478268

  3. Multi-Partner Experiment to Test Volcanic-Ash Ingestion by a Jet Engine

    NASA Technical Reports Server (NTRS)

    Lekki, John; Lyall, Eric; Guffanti, Marianne; Fisher, John; Erlund, Beth; Clarkson, Rory; van de Wall, Allan

    2013-01-01

    A research team of U.S. Government agencies and engine manufacturers are designing an experiment to test volcanic-ash ingestion by a NASA owned F117 engine that was donated by the U.S. Air Force. The experiment is being conducted under the auspices of NASA s Vehicle Integrated Propulsion Research (VIPR) Program and will take place in early 2014 at Edwards AFB in California as an on-ground, on-wing test. The primary objectives are to determine the effect on the engine of several hours of exposure to low to moderate ash concentrations, currently proposed at 1 and 10 mg/m3 and to evaluate the capability of engine health management technologies for detecting these effects. A natural volcanic ash will be used that is representative of distal ash clouds many 100's to approximately 1000 km from a volcanic source i.e., the ash should be composed of fresh glassy particles a few tens of microns in size. The glassy ash particles are expected to soften and become less viscous when exposed to the high temperatures of the combustion chamber, then stick to the nozzle guide vanes of the high-pressure turbine. Numerous observations and measurements of the engine s performance and degradation will be made during the course of the experiment, including borescope and tear-down inspections. While not intended to be sufficient for rigorous certification of engine performance when ash is ingested, the experiment should provide useful information to aircraft manufacturers, airline operators, and military and civil regulators in their efforts to evaluate the range of risks that ash hazards pose to aviation.

  4. Modelling wet deposition in simulations of volcanic ash dispersion from hypothetical eruptions of Merapi, Indonesia

    NASA Astrophysics Data System (ADS)

    Dare, Richard A.; Potts, Rodney J.; Wain, Alan G.

    2016-10-01

    The statistical impact of including the process of wet deposition in dispersion model predictions of the movement of volcanic ash is assessed. Based on hypothetical eruptions of Merapi, Indonesia, sets of dispersion model simulations were generated, each containing four simulations per day over a period of three years, to provide results based on a wide range of atmospheric conditions. While on average dry sedimentation removes approximately 10% of the volcanic ash from the atmosphere during the first 24 h, wet deposition removes an additional 30% during seasons with highest rainfall (December and January) but only an additional 1% during August and September. The majority of the wet removal is due to in-cloud rather than below-cloud collection of volcanic ash particles. The largest uncertainties in the amount of volcanic ash removed by the process of wet deposition result from the choice of user-defined parameters used to compute the scavenging coefficient, and from the definition of the cloud top height. Errors in the precipitation field provided by the numerical weather prediction model utilised here have relatively less impact.

  5. An "Adventure" of MBA Students in Europe: How Volcanic Ash Produced an Incidental Learning Experience

    ERIC Educational Resources Information Center

    Vazquez, Ana Claudia Souza; Ruas, Roberto Lima; Cervo, Clarissa S.; Hutz, Claudio Simon

    2013-01-01

    Because the volcanic ash that affected air travel in Western Europe in 2010 was considered as one of the most meaningful learning experiences by a group of MBA students, this article aims to outline the main aspects of an incidental learning situation, rarely described on management education literature. Incidental learning is an unsystematic…

  6. Automatic volcanic ash detection from MODIS observations using a back-propagation neural network

    NASA Astrophysics Data System (ADS)

    Gray, T. M.; Bennartz, R.

    2015-08-01

    Due to the climate effects and aviation threats of volcanic eruptions, it is important to accurately locate ash in the atmosphere. This study aims to explore the accuracy and reliability of training a neural network to identify cases of ash using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). Satellite images were obtained for the following eruptions: Kasatochi, Aleutian Islands, 2008; Okmok, Aleutian Islands, 2008; Grímsvötn, northeastern Iceland, 2011; Chaiteìn, southern Chile, 2008; Puyehue-Cordoìn Caulle, central Chile, 2011; Sangeang Api, Indonesia, 2014; and Kelut, Indonesia, 2014. The Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) was used to obtain ash concentrations for the same archived eruptions. Two back-propagation neural networks were then trained using brightness temperature differences as inputs obtained via the following band combinations: 12-11, 11-8.6, 11-7.3, and 11 μm. Using the ash concentrations determined via HYSPLIT, flags were created to differentiate between ash (1) and no ash (0) and SO2-rich ash (1) and no SO2-rich ash (0) and used as output. When neural network output was compared to the test dataset, 93 % of pixels containing ash were correctly identified and 7 % were missed. Nearly 100 % of pixels containing SO2-rich ash were correctly identified. The optimal thresholds, determined using Heidke skill scores, for ash retrieval and SO2-rich ash retrieval were 0.48 and 0.47, respectively. The networks show significantly less accuracy in the presence of high water vapor, liquid water, ice, or dust concentrations. Significant errors are also observed at the edge of the MODIS swath.

  7. Automatic volcanic ash detection from MODIS observations using a back-propagation neural network

    NASA Astrophysics Data System (ADS)

    Gray, T. M.; Bennartz, R.

    2015-12-01

    Due to the climate effects and aviation threats of volcanic eruptions, it is important to accurately locate ash in the atmosphere. This study aims to explore the accuracy and reliability of training a neural network to identify cases of ash using observations from the Moderate Resolution Imaging Spectroradiometer (MODIS). Satellite images were obtained for the following eruptions: Kasatochi, Aleutian Islands, 2008; Okmok, Aleutian Islands, 2008; Grímsvötn, northeastern Iceland, 2011; Chaitén, southern Chile, 2008; Puyehue-Cordón Caulle, central Chile, 2011; Sangeang Api, Indonesia, 2014; and Kelut, Indonesia, 2014. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model was used to obtain ash concentrations for the same archived eruptions. Two back-propagation neural networks were then trained using brightness temperature differences as inputs obtained via the following band combinations: 12-11, 11-8.6, 11-7.3, and 11 μm. Using the ash concentrations determined via HYSPLIT, flags were created to differentiate between ash (1) and no ash (0) and SO2-rich ash (1) and no SO2-rich ash (0) and used as output. When neural network output was compared to the test data set, 93 % of pixels containing ash were correctly identified and 7 % were missed. Nearly 100 % of pixels containing SO2-rich ash were correctly identified. The optimal thresholds, determined using Heidke skill scores, for ash retrieval and SO2-rich ash retrieval were 0.48 and 0.47, respectively. The networks show significantly less accuracy in the presence of high water vapor, liquid water, ice, or dust concentrations. Significant errors are also observed at the edge of the MODIS swath.

  8. Quantification of L-band InSAR decorrelation in volcanic terrains using airborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Sedze, M.; Heggy, E.; Jacquemoud, S.; Bretar, F.

    2011-12-01

    Repeat-pass InSAR LOS measurements of the Piton de La Fournaise (La Reunion Island, France) suffer from substantial phase decorrelation due to the occurrence of vegetation and ash deposits on the caldera and slopes of the edifice. To correct this deficiency, we combine normalized airborne LiDAR (Light Detection and Ranging) intensity data with spaceborne InSAR coherence images from ALOS PALSAR L-band acquired over the volcano in 2008 and 2009, following the 2007 major eruption. The fusion of the two data sets improves the calculation of coherence and the textural classification of different volcanic surfaces. For future missions considering both InSAR and/or LiDAR such as DESDynI (Deformation, Ecosystem Structure and Dynamics of Ice), such data fusion studies can provide a better analysis of the spatiotemporal variations in InSAR coherence in order to enhance the monitoring of pre-eruptive ground displacements. The airborne surveys conducted in 2008 and 2009, cover different types of vegetation and terrain roughness on the central and western parts of the volcano. The topographic data are first processed to generate a high-resolution digital terrain model (DTM) of the volcanic edifice with elevation accuracy better than 1 m. For our purposes, the phase variations caused by the surface relief can be eliminated using the LiDAR-derived DTM. Then normalized LiDAR intensities are correlated to the L-band polarimetric coherence for different zones of the volcano to assess the LiDAR-InSAR statistical behavior of different lava flows, pyroclastics, and vegetated surfaces. Results suggest that each volcanic terrain type is characterized by a unique LiDAR-InSAR histogram pattern. We identified four LiDAR-InSAR distinguished relations: (1) pahoehoe lava flow surfaces show an agglomerate histogram pattern which may be explained by low surface scattering and low wave penetration into the geological medium; (2) eroded a'a lava surfaces is characterized by high standard deviation

  9. Experimental volcanic ash aggregation: Internal structuring of accretionary lapilli and the role of liquid bonding

    NASA Astrophysics Data System (ADS)

    Mueller, Sebastian B.; Kueppers, Ulrich; Ayris, Paul M.; Jacob, Michael; Dingwell, Donald B.

    2016-01-01

    Explosive volcanic eruptions can release vast quantities of pyroclastic material into Earth's atmosphere, including volcanic ash, particles with diameters less than two millimeters. Ash particles can cluster together to form aggregates, in some cases reaching up to several centimeters in size. Aggregation alters ash transport and settling behavior compared to un-aggregated particles, influencing ash distribution and deposit stratigraphy. Accretionary lapilli, the most commonly preserved type of aggregates within the geologic record, can exhibit complex internal stratigraphy. The processes involved in the formation and preservation of these aggregates remain poorly constrained quantitatively. In this study, we simulate the variable gas-particle flow conditions which may be encountered within eruption plumes and pyroclastic density currents via laboratory experiments using the ProCell Lab System® of Glatt Ingenieurtechnik GmbH. In this apparatus, solid particles are set into motion in a fluidized bed over a range of well-controlled boundary conditions (particle concentration, air flow rate, gas temperature, humidity, liquid composition). Experiments were conducted with soda-lime glass beads and natural volcanic ash particles under a range of experimental conditions. Both glass beads and volcanic ash exhibited the capacity for aggregation, but stable aggregates could only be produced when materials were coated with high but volcanically-relevant concentrations of NaCl. The growth and structure of aggregates was dependent on the initial granulometry, while the rate of aggregate formation increased exponentially with increasing relative humidity (12-45% RH), before overwetting promoted mud droplet formation. Notably, by use of a broad granulometry, we generated spherical, internally structured aggregates similar to some accretionary pellets found in volcanic deposits. Adaptation of a powder-technology model offers an explanation for the origin of natural accretionary

  10. The future of volcanic ash-aircraft interactions from technical and policy perspectives

    NASA Astrophysics Data System (ADS)

    Casadevall, T. J.; Guffanti, M.

    2010-12-01

    Since the advent of jet-powered flight in the 1960s, the threat of volcanic ash to aviation operations has become widely recognized and the mitigation of this threat has received concerted international attention. At the same time the susceptibility to operational disruption has grown. Technical improvements to airframes, engines, and avionic systems have been made in response to the need for improved fuel efficiency and the demand for increased capacity for passenger and freight traffic. Operational demands have resulted in the growth of extended overseas flight operations (ETOPS), increased flight frequency on air traffic routes, and closer spacing of aircraft on heavily traveled routes. The net result has been great advances in flight efficiency, but also increased susceptibility to flight disruption, especially in heavily traveled regions such as North Atlantic-Europe, North America, and the North Pacific. Advances in ash avoidance procedures, pilot and air manager training, and in detection of ash-related damage and maintenance of aircraft and engines have been spurred by noteworthy eruptions such as Galunggung, Indonesia, 1982; Redoubt, Alaska, 1989-1990; and Pinatubo, Philippines, 1991. Comparable advances have been made in the detection and tracking of volcanic ash clouds using satellite-based remote sensing and numerical trajectory forecast models. Following the April 2010 eruption of Eyjafjallajökull volcano, Iceland, the global aviation community again focused attention on the issue of safe air operations in airspace affected by volcanic ash. The enormous global disruption to air traffic in the weeks after the Eyjafjallajökull eruption has placed added emphasis for the global air traffic management system as well as on the equipment manufacturers to reevaluate air operations in ash-affected airspace. Under the leadership of the International Civil Aviation Organization and the World Meteorological Organization, efforts are being made to address this

  11. Experiments on gas-ash separation processes in volcanic umbrella plumes

    NASA Astrophysics Data System (ADS)

    Holasek, Rick E.; Woods, Andrew W.; Self, Stephen

    1996-03-01

    We present a series of analogue laboratory experiments which simulate the separation of ash and gas and the formation of secondary intrusions from finite volcanic umbrella plumes. We examined the lateral spreading of mixtures of freshwater and particles released into a laboratory tank containing a uniformly stratified aqueous solution. For times smaller than the sedimentation time of particles through the intrusion, the current remains coherent and intrudes laterally. As some of the particles settle into the underlying ambient fluid, a layer of particle-depleted fluid develops below the upper surface of the current and the density of the residual fluid is reduced. Over longer times, the intrusion ceases to be coherent, with small fingers of relatively buoyant, particle-depleted fluid rising from the upper part of the intrusion into the overlying fluid. Meanwhile, the lateral motion of the injected solution induces a return flow in the ambient fluid which sweeps some of the particles sedimenting from the lower surface of the intrusion inwards. As a result, relatively dense particle-laden fluid collects below the intrusion and then sinks into the underlying fluid. Eventually this fluid reaches a new neutral buoyancy height, where it intrudes to form a second laterally spreading current below the original intrusion. The process then repeats to form further weaker intrusions below. These results of the separation of the ash and volcanic gas in an umbrella plume are consistent with field observations at Sakurajima volcano where positively charged plumes, thought to consist of volcanic gas, have been observed above negatively charged plumes of ash. This work also suggests that volcanic aerosols may form up to a kilometer above the original injection height of the ash. In a strong wind shear, this could result in very different trajectories of the ash and gas and so be important for evaluating the impact of ash plumes on both aviation safety and volcanic aerosol formation

  12. Deriving the concentration of airborne ash with a CAS-DPOL instrument: assessing uncertainties introduced by the instrument design

    NASA Astrophysics Data System (ADS)

    Spanu, Antonio; Weinzierl, Bernadett; Freudenthaler, Volker; Sauer, Daniel; Gasteiger, Josef

    2016-04-01

    Explosive volcanic eruptions inject large amounts of gas and particles into the atmosphere resulting in strong impacts on anthropic systems and climate. Fine ash particles in suspension, even if at low concentrations, are a serious aviation safety hazard. A key point to predict the dispersion and deposition of volcanic ash is the knowledge of emitted mass and its particle size distribution. Usually the deposit is used to characterize the source but a large uncertainty is present for fine and very fine ash particles which are usually not well preserved. Conversely, satellite observations provide only column-integrated information and are strongly sensitive to cloud conditions above the ash plumes. Consequently, in situ measurements are fundamental to extend our knowledge on ash clouds, their properties, and interactions over the vertical extent of the atmosphere. Different in-situ instruments are available covering different particle size ranges using a variety of measurement techniques. Depending on the measurement technique, artefacts due to instrument setup and ambient conditions can strongly modify the measured number concentration and size distribution of the airborne particles. It is fundamental to correct for those effects to quantify the uncertainty associated with the measurement. Here we evaluate the potential of our optical light-scattering spectrometer CAS-DPOL to detect airborne mineral dust and volcanic ash (in the size range between 0.7μm and 50μm) and to provide a reliable estimation of the mass concentration, investigating the associate uncertainty. The CAS-DPOL instrument sizes particles by detecting the light scattered off the particle into a defined angle. The associated uncertainty depends on the optical instrument design and on unknown particles characteristics such as shape and material. Indirect measurements of mass concentrations are statistically reconstructed using the air flow velocity. Therefore, the detected concentration is strongly

  13. Dust, Volcanic Ash, and the Evolution of the South Pacific Gyre through the Cenozoic

    NASA Astrophysics Data System (ADS)

    Dunlea, A. G.; Murray, R. W.; Sauvage, J.; Spivack, A. J.; Harris, R. N.; D'Hondt, S.; Higgins, J. A.

    2015-12-01

    Dust and volcanic ash play a critical role in past global climate by affecting cloud cover and ocean nutrients as well as responding to changes in tectonics, aridity, and wind. Because the eolian fluxes in the Southern Hemisphere are so low, subtle changes in the absolute flux of dust and volcanic ash may have a disproportionally large impact on climate. Our multi-site record of eolian dust and volcanic ash accumulation in pelagic clay of the South Pacific Gyre (SPG), gathered during IODP Expedition 329, shows that eolian fluxes varied by an order of magnitude over the Cenozoic and correlate with changes of tectonic processes and global climate. We analyzed the concentrations of 37 elements in 138 bulk pelagic clay samples from 6 sites drilled throughout the SPG. Using multivariate statistical modeling of the geochemical dataset (e.g. Q-mode factor analysis and multiple linear regression) and a cobalt-based age model, we quantified the mass accumulation rate (MAR) of 6 end-members that comprise the SPG pelagic clay: dust, rhyolite, altered basalt, Fe-Mn oxyhydroxides, excess Si, and apatite. Our record shows that Australian dust MAR begins at the Early Eocene Climatic Optimum ~50 Ma as global temperatures began to cool and Australia began to tectonically separate from Antarctica. The mid-Miocene has noticeably higher MAR of dust and ash at multiple sites. While a simultaneous increase in production is possible (i.e., more aridity and volcanic activity), the synchronicity may be more indicative of stronger winds in the Southern Hemisphere and increased material in the atmosphere during this time. Heavier Mg isotopes occur at Site U1366 in samples that are composed primarily of hydrothermal deposition, excess Si, and volcanic ash. The Mg isotopic enrichment suggests that these components have undergone alterations to form authigenic aluminosilicates.

  14. Ash iron mobilization through physicochemical processing in volcanic eruption plumes: a numerical modeling approach

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, G. A.; Hort, M.; Langmann, B.

    2015-08-01

    It has been shown that volcanic ash fertilizes the Fe-limited areas of the surface ocean through releasing soluble iron. As ash iron is mostly insoluble upon the eruption, it is hypothesized that heterogeneous in-plume and in-cloud processing of the ash promote the iron solubilization. Direct evidences concerning such processes are, however, lacking. In this study, a 1-D numerical model is developed to simulate the physicochemical interactions of the gas-ash-aerosol in volcanic eruption plumes focusing on the iron mobilization processes at temperatures between 600 and 0 °C. Results show that sulfuric acid and water vapor condense at ~ 150 and ~ 50 °C on the ash surface, respectively. This liquid phase then efficiently scavenges the surrounding gases (> 95 % of HCl, 3-20 % of SO2 and 12-62 % of HF) forming an extremely acidic coating at the ash surface. The low pH conditions of the aqueous film promote acid-mediated dissolution of the Fe-bearing phases present in the ash material. We estimate that 0.1-33 % of the total iron available at the ash surface is dissolved in the aqueous phase before the freezing point is reached. The efficiency of dissolution is controlled by the halogen content of the erupted gas as well as the mineralogy of the iron at ash surface: elevated halogen concentrations and presence of Fe2+-carrying phases lead to the highest dissolution efficiency. Findings of this study are in agreement with the data obtained through leaching experiments.

  15. The in vitro respiratory toxicity of cristobalite-bearing volcanic ash.

    PubMed

    Damby, David E; Murphy, Fiona A; Horwell, Claire J; Raftis, Jennifer; Donaldson, Kenneth

    2016-02-01

    Ash from dome-forming volcanoes poses a unique hazard to millions of people worldwide due to an abundance of respirable cristobalite, a crystalline silica polymorph. Crystalline silica is an established respiratory hazard in other mixed dusts, but its toxicity strongly depends on sample provenance. Previous studies suggest that cristobalite-bearing volcanic ash is not as bio-reactive as may be expected for a dust containing crystalline silica. We systematically address the hazard posed by volcanic cristobalite by analysing a range of dome-related ash samples, and interpret the crystalline silica hazard according to the mineralogical nature of volcanic cristobalite. Samples are sourced from five well-characterized dome-forming volcanoes that span a range of magmatic compositions, specifically selecting samples rich in cristobalite (up to 16wt%). Isolated respirable fractions are used to investigate the in vitro response of THP-1 macrophages and A549 type II epithelial cells in cytotoxicity, cellular stress, and pro-inflammatory assays associated with crystalline silica toxicity. Dome-related ash is minimally reactive in vitro for a range of source compositions and cristobalite contents. Cristobalite-based toxicity is not evident in the assays employed, supporting the notion that crystalline silica provenance influences reactivity. Macrophages experienced minimal ash-induced cytotoxicity and intracellular reduction of glutathione; however, production of IL-1β, IL-6 and IL-8 were sample-dependent. Lung epithelial cells experienced moderate apoptosis, sample-dependent reduction of glutathione, and minimal cytokine production. We suggest that protracted interaction between particles and epithelial cells may never arise due to effective clearance by macrophages. However, volcanic ash has the propensity to incite a low, but significant, and sample-dependent response; the effect of this response in vivo is unknown and prolonged exposure may yet pose a hazard. PMID

  16. Potential of thermal infrared radiometry for remote sensing of volcanic ash clouds

    NASA Astrophysics Data System (ADS)

    Dubuisson, P.; Minvielle, F.; Hebin, H.; Thieuleux, F.; Parol, F.; Pelon, J.

    2011-12-01

    This study reports on the optical and microphysical characterization of particles contained in volcanic ash clouds using thermal infrared radiometry. Several works have shown the potential of the split window technique for estimating the effective particle size and optical thickness of semi-transparent clouds from two channels in the infrared atmospheric window (8 - 12 μm). In the present study, this approach is applied to the characterization of volcanic particles. The inversion algorithm is based on LUTs built with an accurate radiative transfer code, including gaseous absorption as well as multiple scattering and absorption by particles. Realistic spectral variations for optical properties of several types of volcanic particle (Ash, H2SO4 ...) and water or ice clouds have been calculated from refractive indices and Mie theory. In addition, this inversion procedure needs to define the altitude, temperature and thickness of the ash cloud. Consequently, meteorological data relative to the atmosphere and the state of ash cloud have been calculated using the Regional Atmospheric Modeling System (RAMS). This model allows giving a 3D dynamical transport of the ash plume and its vertical distribution. Ash sources and scenes area have been studied in detail with higher resolution using nested grid system of the model. In a first step, a sensitivity study based on radiative transfer calculations is presented in order to illustrate the potential of this approach. This technique is then applied to volcanic plumes in April-May 2010. Brightness temperatures from the MODIS spectroradiometer, the Infrared Imaging Radiometer (IIR) and the SEVIRI radiometer are used for some scenes acquired simultaneously over North / West of Europe with similar spectral or spatial resolutions. Spatial distribution of the retrieved optical thickness and effective size of particles are presented and analyzed. Comparisons between retrievals from IIR, MODIS and SEVIRI are presented. Contributions

  17. The in vitro respiratory toxicity of cristobalite-bearing volcanic ash.

    PubMed

    Damby, David E; Murphy, Fiona A; Horwell, Claire J; Raftis, Jennifer; Donaldson, Kenneth

    2016-02-01

    Ash from dome-forming volcanoes poses a unique hazard to millions of people worldwide due to an abundance of respirable cristobalite, a crystalline silica polymorph. Crystalline silica is an established respiratory hazard in other mixed dusts, but its toxicity strongly depends on sample provenance. Previous studies suggest that cristobalite-bearing volcanic ash is not as bio-reactive as may be expected for a dust containing crystalline silica. We systematically address the hazard posed by volcanic cristobalite by analysing a range of dome-related ash samples, and interpret the crystalline silica hazard according to the mineralogical nature of volcanic cristobalite. Samples are sourced from five well-characterized dome-forming volcanoes that span a range of magmatic compositions, specifically selecting samples rich in cristobalite (up to 16wt%). Isolated respirable fractions are used to investigate the in vitro response of THP-1 macrophages and A549 type II epithelial cells in cytotoxicity, cellular stress, and pro-inflammatory assays associated with crystalline silica toxicity. Dome-related ash is minimally reactive in vitro for a range of source compositions and cristobalite contents. Cristobalite-based toxicity is not evident in the assays employed, supporting the notion that crystalline silica provenance influences reactivity. Macrophages experienced minimal ash-induced cytotoxicity and intracellular reduction of glutathione; however, production of IL-1β, IL-6 and IL-8 were sample-dependent. Lung epithelial cells experienced moderate apoptosis, sample-dependent reduction of glutathione, and minimal cytokine production. We suggest that protracted interaction between particles and epithelial cells may never arise due to effective clearance by macrophages. However, volcanic ash has the propensity to incite a low, but significant, and sample-dependent response; the effect of this response in vivo is unknown and prolonged exposure may yet pose a hazard.

  18. Ash-flow tuffs of the Galiuro Volcanics in the northern Galiuro Mountains, Pinal County, Arizona

    USGS Publications Warehouse

    Krieger, Medora Louise Hooper

    1979-01-01

    The upper Oligocene and lower Miocene Galiuro Volcanics in the northern part of the Galiuro Mountains contains two distinctive major ash-flow tuff sheets, the Holy Joe and Aravaipa Members. These major ash-flows illustrate many features of ash-flow geology not generally exposed so completely. The Holy Joe Member, composed of a series of densely welded flows of quartz latite composition that make up a simple cooling unit. is a rare example of a cooling unit that has a vitrophyre at the top as well as at the base. The upper vitrophyre does not represent a cooling break. The Aravaipa Member. a rhyolite, is completely exposed in Aravaipa and other canyons and on Table Mountain. Remarkable exposures along Whitewash Canyon exhibit the complete change from a typical stacked-up interior zonation of an ash flow to a non welded distal margin. Vertical and horizontal changes in welding, crystallization, specific gravity, and lithology are exposed. The ash flow can be divided into six lithologic zones. The Holy Joe and Aravaipa Members of the Galiuro Volcanics are so well exposed and so clearly show characteristic features of ash-flow tuffs that they could be a valuable teaching aid and a source of theses for geology students.

  19. Study on the volcanic ash cloud with Feng Yun-3 meteorological satellite data

    NASA Astrophysics Data System (ADS)

    Gong, Cai-lan T.; Jiang, Shan; Hu, Yong; Meng, Peng

    2013-09-01

    Volcano eruption can produce a mass of volcanic ash floating in the air for a long period, which will seriously threaten the aerial planes safety, and cause the air pollution, it could do harm to people's living environment and their health. Take the Iceland Eyjafjallajokull volcano as an example which erupted in April to May 2010, the volcano ash cloud were derived with the visible and infrared scanning radiometer of FengYun-3(FY-3 VIRR) meteorological satellite data. The medium wave infrared (MWIR) and the thermal infrared split windows (THIR-SW) data were used separately. the MODIS THIR-SW data were also be used to retrieve ash cloud to test the results derived from FY-3 VIRR data. It showed that the MWIR was more applicable for the ash cloud retrieving than the THIR-SW with FY-3 VIRR data, and the threshold value should be adjusted to around negative 1 rather than 0 for VIRR THIR-SW data. And the threshold should be adjusted with the THIR-SW of FY-3. The ash cloud radiation and bright temperature(BT), spatial distribution characteristics were also analyzed quantitatively with the two channels data. The study could provide parameters for the prediction of volcanic ash cloud dispersion simulate. When the real temperature of lava flow were high enough, the sensor will show a false bright temperature, how to retrieve the real temperature of the higher lava flow is a problem need to be studied in the future.

  20. Triboelectric charging of volcanic ash from Grímsvötn

    NASA Astrophysics Data System (ADS)

    Houghton, Isobel; Aplin, Karen; Nicoll, Keri

    2013-04-01

    Volcanic ash is known to charge electrically, producing some of the most spectacular displays of lightning in nature. Triboelectric charging is one mechanism associated with volcanic plume electrification. Previous theoretical work on triboelectric charging of single-material particle systems has shown that the charging is likely to be determined by the number size distribution (Lacks and Levandovsky, 2007). Here we investigate triboelectric charging of a sample of ash from the Grímsvötn eruption in 2011 using a specially designed apparatus. Ash is released to fall under gravity through a screened metal cylinder and into an isolated Faraday cup. A sensitive electrometer is used to measure the voltage change associated with the charge on the ash. The release mechanism has been designed to facilitate only self-charging of the ash, as is expected in the atmospheric plume. Using geological sieves to separate the sample into different size fractions, we were able to create artificial size distributions to investigate the effects of changing the number size distribution. We find that for a sample with a narrow range of particle sizes, the Faraday cup voltage change is much smaller than for a sample with a wide range of particle sizes, in agreement with theory. These results demonstrate that self-charging of ash through triboelectrification is likely, supporting both a frictional origin for the sustained lightning observed during the Grímsvötn eruption, and other observations of self-charging in a plume distant from the source.

  1. MODIS volcanic ash retrievals vs FALL3D transport model: a quantitative comparison

    NASA Astrophysics Data System (ADS)

    Corradini, S.; Merucci, L.; Folch, A.

    2010-12-01

    Satellite retrievals and transport models represents the key tools to monitor the volcanic clouds evolution. Because of the harming effects of fine ash particles on aircrafts, the real-time tracking and forecasting of volcanic clouds is key for aviation safety. Together with the security reasons also the economical consequences of a disruption of airports must be taken into account. The airport closures due to the recent Icelandic Eyjafjöll eruption caused millions of passengers to be stranded not only in Europe, but across the world. IATA (the International Air Transport Association) estimates that the worldwide airline industry has lost a total of about 2.5 billion of Euro during the disruption. Both security and economical issues require reliable and robust ash cloud retrievals and trajectory forecasting. The intercomparison between remote sensing and modeling is required to assure precise and reliable volcanic ash products. In this work we perform a quantitative comparison between Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals of volcanic ash cloud mass and Aerosol Optical Depth (AOD) with the FALL3D ash dispersal model. MODIS, aboard the NASA-Terra and NASA-Aqua polar satellites, is a multispectral instrument with 36 spectral bands operating in the VIS-TIR spectral range and spatial resolution varying between 250 and 1000 m at nadir. The MODIS channels centered around 11 and 12 micron have been used for the ash retrievals through the Brightness Temperature Difference algorithm and MODTRAN simulations. FALL3D is a 3-D time-dependent Eulerian model for the transport and deposition of volcanic particles that outputs, among other variables, cloud column mass and AOD. Three MODIS images collected the October 28, 29 and 30 on Mt. Etna volcano during the 2002 eruption have been considered as test cases. The results show a general good agreement between the retrieved and the modeled volcanic clouds in the first 300 km from the vents. Even if the

  2. Electrical Properties Of Volcanic Ash Samples From Grímsvötn

    NASA Astrophysics Data System (ADS)

    Houghton, I. M.; Aplin, K. L.; Nicoll, K. A.; Green, O.; Mather, T. A.

    2012-12-01

    Recent Icelandic eruptions in 2012 and 2011 were associated with sustained charging of the ash plume (Harrison et al., 2010) and significant volcanic lightning (Bennett et al., 2010; Arason et al., 2012). The sustained charging suggests that some charging of the plume is independent of the eruption process, in addition to other electrification mechanisms such as triboelectric or fractoemission processes at the vent, the 'dirty thunderstorm' mechanism if ice forms in the plume, and the internal radioactivity of the plume (Mather and Harrison, 2006; James et al., 2008). We investigate the triboelectric charging of volcanic material using a charged particle apparatus, which allows the charged particles to fall under gravity in a screened metallic cylinder. This apparatus comprises two induction rings connected to sensitive electrometers, which detect charge induced by the falling ash, and a Faraday cup to measure the total ash charge. The release mechanism has been designed to facilitate only self charging of the ash, as is expected in the atmospheric plume. Previous work on triboelectric charging of single-material particle systems has shown that the charging is likely to be determined by the number size distribution (Lacks and Levandovsky, 2007). We present a mass distribution measurement for a sample of volcanic ash provided by the Icelandic Meteorological Office collected 70 km from the crater of the 2011 Grímsvötn eruption. This shows a high proportion of fine particles compared with the volumetric size distribution reported in Piper et al. (2012). Optical microscopy of the different size fractions of the Grímsvötn sample indicates that the composition varies with size. In addition to charge transfer as a function of size, the different substances will triboelectrically interact with each other, which complicates the nature of the charge interactions. To separate the dependence of particle charging on size from composition, particle charging experiments were

  3. Ground-based analysis of volcanic ash plumes using a new multispectral thermal infrared camera approach

    NASA Astrophysics Data System (ADS)

    Williams, D.; Ramsey, M. S.

    2015-12-01

    Volcanic plumes are complex mixtures of mineral, lithic and glass fragments of varying size, together with multiple gas species. These plumes vary in size dependent on a number of factors, including vent diameter, magma composition and the quantity of volatiles within a melt. However, determining the chemical and mineralogical properties of a volcanic plume immediately after an eruption is a great challenge. Thermal infrared (TIR) satellite remote sensing of these plumes is routinely used to calculate the volcanic ash particle size variations and sulfur dioxide concentration. These analyses are commonly performed using high temporal, low spatial resolution satellites, which can only reveal large scale trends. What is lacking is a high spatial resolution study specifically of the properties of the proximal plumes. Using the emissive properties of volcanic ash, a new method has been developed to determine the plume's particle size and petrology in spaceborne and ground-based TIR data. A multispectral adaptation of a FLIR TIR camera has been developed that simulates the TIR channels found on several current orbital instruments. Using this instrument, data of volcanic plumes from Fuego and Santiaguito volcanoes in Guatemala were recently obtained Preliminary results indicate that the camera is capable of detecting silicate absorption features in the emissivity spectra over the TIR wavelength range, which can be linked to both mineral chemistry and particle size. It is hoped that this technique can be expanded to isolate different volcanic species within a plume, validate the orbital data, and ultimately to use the results to better inform eruption dynamics modelling.

  4. Volcanic ash dispersed in the Wyodak-Anderson coal bed, Powder River Basin, Wyoming

    USGS Publications Warehouse

    Triplehorn, D.M.; Stanton, R.W.; Ruppert, L.F.; Crowley, S.S.

    1991-01-01

    Minerals derived from air-fall volcanic ash were found in two zones in the upper Paleocene Wyodak-Anderson coal bed of the Fort Union Formation in the Powder River Basin of Wyoming, and are the first reported evidence of such volcanic material in this thick (> 20 m) coal bed. The volcanic minerals occur in zones that are not visually obvious because they contain little or no clay. These zones were located by geophysical logs of the boreholes and X-ray radiography of the cores. The zones correspond to two of a series of incremental core samples of the coal bed that have anomalous concentrations of Zr, Ba, Nb, Sr, and P2O5. Two suites of minerals were found in both of the high-density zones. A primary suite (not authigenic) consists of silt-sized quartz grains, biotite, and minor zircon. A minor suite consists of authigenic minerals, including calcite, pyrite, kaolinite, quartz, anatase, barite, and an alumino-phosphate (crandallite?). The original volcanic ash is inferred to have consisted of silica glass containing phenocrysts of quartz, biotite, zircon, and possibly, associated feldspars, pyroxenes, and amphiboles. The glass, as well as the less stable minerals, probably dissolved relatively quickly and contributed to the minor authigenic mineral suite or was removed from the peat as a result of the prevailing hydrologic conditions present in a raised peat formation. This type of volcanic ash suggests that suggests that volcanic material could have rained on the peat; this fallout may have also had a fertilizing effect on the peat by providing nutrients essential for plant growth thus contributing to the thick accumulations of the Wyodak-Anderson bed. Notwithstanding, the presence of these minerals provides evidence for the contribution by volcanic sources to the mineral content of coal, but not as tonsteins. ?? 1991.

  5. Volcanic Ash and SO2 Monitoring Using Suomi NPP Direct Broadcast OMPS Data

    NASA Astrophysics Data System (ADS)

    Seftor, C. J.; Krotkov, N. A.; McPeters, R. D.; Li, J. Y.; Brentzel, K. W.; Habib, S.; Hassinen, S.; Heinrichs, T. A.; Schneider, D. J.

    2014-12-01

    NASA's Suomi NPP Ozone Science Team, in conjunction with Goddard Space Flight Center's (GSFC's) Direct Readout Laboratory, developed the capability of processing, in real-time, direct readout (DR) data from the Ozone Mapping and Profiler Suite (OMPS) to perform SO2 and Aerosol Index (AI) retrievals. The ability to retrieve this information from real-time processing of DR data was originally developed for the Ozone Monitoring Instrument (OMI) onboard the Aura spacecraft and is used by Volcano Observatories and Volcanic Ash Advisory Centers (VAACs) charged with mapping ash clouds from volcanic eruptions and providing predictions/forecasts about where the ash will go. The resulting real-time SO2 and AI products help to mitigate the effects of eruptions such as the ones from Eyjafjallajokull in Iceland and Puyehue-Cordón Caulle in Chile, which cause massive disruptions to airline flight routes for weeks as airlines struggle to avoid ash clouds that could cause engine failure, deeply pitted windshields impossible to see through, and other catastrophic events. We will discuss the implementation of real-time processing of OMPS DR data by both the Geographic Information Network of Alaska (GINA) and the Finnish Meteorological Institute (FMI), which provide real-time coverage over some of the most congested airspace and over many of the most active volcanoes in the world, and show examples of OMPS DR processing results from recent volcanic eruptions.

  6. Volcanic Ash and Aviation - the 2014 Eruptions of Kelut and Sangeang Api, Indonesia

    NASA Astrophysics Data System (ADS)

    Tupper, A. C.; Jansons, E.

    2014-12-01

    Two significant eruptions in Indonesia during the first part of 2014 have highlighted the continuing challenges of safe air traffic management around volcanic ash clouds. The stratospheric eruption of Kelut (also known as Kelud) in Java late on 13 February 2014 resulted in widespread aviation disruption over Indonesia and at least one serious volcanic ash encounter from an international airline. An upper-tropospheric eruption of Sangeang Api in the Lesser Sunda Islands on 30 May 2014 did not result in any known aircraft encounters, but did result in many delays and flight cancellations between Indonesia and Australia. In both cases, the eruption and resultant ash clouds were relatively well observed, if subject to the usual issues in characterising such clouds. For example, as tropical eruptions frequently reach 15 km amsl and above due to the height of the tropical tropopause, it is frequently very difficult to provide an accurate estimation of conditions at the cruising levels of aircraft, at 10-11 km (or lower for shorter domestic routes). More critically, the challenge of linking operational results from two scientific professions (volcanology and meteorology) with real-time aviation users remains strongly evident. Situational awareness of domestic and international airlines, ground-based monitoring and communications prior to and during the eruption, receiving and sharing pilot reports of volcanic ash, and appropriate flight responses all remain inadequate even in relatively fine conditions, with an unacceptable ongoing risk of serious aviation encounters should improvements not be made. Despite the extensive efforts of the International Civil Aviation Organization, World Meteorological Organization, and all partners in the International Airways Volcano Watch, and despite the acceleration of work on the issue since 2010, volcanic ash management remains sub-optimal.

  7. Modelling the resuspension of volcanic ash from the Valley of Ten Thousand Smokes

    NASA Astrophysics Data System (ADS)

    Schwaiger, H. F.; Wallace, K.

    2015-12-01

    The 1912 eruption of Novarupta-Katmai was the world's most voluminous eruption since the 1815 eruption of Tombora. The eruption produced 17 km3 of ashfall and 11 km3 of pyroclastic flow deposits that filled nearby valleys, creating what is today known as the Valley of Ten Thousand Smokes. These voluminous pyroclastic deposits continue to pose hazards when strong winds in the valley resuspend ash in times of low snow cover. These resuspension events may be confined to the valley and only recorded when there are local observations (web camera images, field crew). Occasionally, however, these events can loft ash up to altitudes of several kilometers and extend up to 250 km downwind, where it becomes an aviation hazard. A compilation of satellite observations and pilot reports indicate that such significant events occurred on at least 19 occasions since 2003. The longest duration events occurred in the autumn months of September and October. Predicting the resuspension of ash requires estimates of when the ash is exposed (low snow cover), the magnitude of surface wind gusts, and the threshold friction velocity (u*). Models of u* require a characterization of the source ash (density, grain-size distribution) as well as soil moisture. We have sampled source deposits and have installed instruments in the Katmai region to record the relevant meteorological parameters in order to better predict these resuspension events. Using real-time measurements coupled with high-resolution (6 km, 1 hour) meteorological forecast products and a reanalysis of conditions that produced historic events, we constrain the parameters applicable the resuspension of Novarupta ash thus improving our ability to forecast this potential ash hazard. The volcanic ash dispersion and deposition model, Ash3d, will be used to forecast the transport of the resuspended ash.

  8. Classification of volcanic ash particles from Sakurajima volcano using CCD camera image and cluster analysis

    NASA Astrophysics Data System (ADS)

    Miwa, T.; Shimano, T.; Nishimura, T.

    2012-12-01

    Quantitative and speedy characterization of volcanic ash particle is needed to conduct a petrologic monitoring of ongoing eruption. We develop a new simple system using CCD camera images for quantitatively characterizing ash properties, and apply it to volcanic ash collected at Sakurajima. Our method characterizes volcanic ash particles by 1) apparent luminance through RGB filters and 2) a quasi-fractal dimension of the shape of particles. Using a monochromatic CCD camera (Starshoot by Orion Co. LTD.) attached to a stereoscopic microscope, we capture digital images of ash particles that are set on a glass plate under which white colored paper or polarizing plate is set. The images of 1390 x 1080 pixels are taken through three kinds of color filters (Red, Green and Blue) under incident-light and transmitted-light through polarizing plate. Brightness of the light sources is set to be constant, and luminance is calibrated by white and black colored papers. About fifteen ash particles are set on the plate at the same time, and their images are saved with a bit map format. We first extract the outlines of particles from the image taken under transmitted-light through polarizing plate. Then, luminances for each color are represented by 256 tones at each pixel in the particles, and the average and its standard deviation are calculated for each ash particle. We also measure the quasi-fractal dimension (qfd) of ash particles. We perform box counting that counts the number of boxes which consist of 1×1 and 128×128 pixels that catch the area of the ash particle. The qfd is estimated by taking the ratio of the former number to the latter one. These parameters are calculated by using software R. We characterize volcanic ash from Showa crater of Sakurajima collected in two days (Feb 09, 2009, and Jan 13, 2010), and apply cluster analyses. Dendrograms are formed from the qfd and following four parameters calculated from the luminance: Rf=R/(R+G+B), G=G/(R+G+B), B=B/(R+G+B), and

  9. Modernization of the International Volcanic Ash Website - a global resource for ashfall preparedness and impact guidance.

    NASA Astrophysics Data System (ADS)

    Wallace, K.; Leonard, G.; Stewart, C.; Wilson, T. M.; Randall, M.; Stovall, W. K.

    2015-12-01

    The internationally collaborative volcanic ash website (http://volcanoes.usgs.gov/ash/) has been an important global information resource for ashfall preparedness and impact guidance since 2004. Recent volcanic ashfalls with significant local, regional, and global impacts highlighted the need to improve the website to make it more accessible and pertinent to users worldwide. Recently, the Volcanic Ash Impacts Working Group (Cities and Volcanoes Commission of IAVCEI) redesigned and modernized the website. Improvements include 1) a database-driven back end, 2) reorganized menu navigation, 3) language translation, 4) increased downloadable content, 5) addition of ash-impact case studies, 7) expanded and updated references , 8) an image database, and 9) inclusion of cooperating organization's logos. The database-driven platform makes the website more dynamic and efficient to operate and update. New menus provide information about specific impact topics (buildings, transportation, power, health, agriculture, water and waste water, equipment and communications, clean up) and updated content has been added throughout all topics. A new "for scientists" menu includes information on ash collection and analysis. Website translation using Google translate will significantly increase user base. Printable resources (e.g. checklists, pamphlets, posters) provide information to people without Internet access. Ash impact studies are used to improve mitigation measures during future eruptions, and links to case studies will assist communities' preparation and response plans. The Case Studies menu is intended to be a living topic area, growing as new case studies are published. A database of all images from the website allows users to access larger resolution images and additional descriptive details. Logos clarify linkages among key contributors and assure users that the site is authoritative and science-based.

  10. Computation of probabilistic hazard maps and source parameter estimation for volcanic ash transport and dispersion

    SciTech Connect

    Madankan, R.; Pouget, S.; Singla, P.; Bursik, M.; Dehn, J.; Jones, M.; Patra, A.; Pavolonis, M.; Pitman, E.B.; Singh, T.; Webley, P.

    2014-08-15

    Volcanic ash advisory centers are charged with forecasting the movement of volcanic ash plumes, for aviation, health and safety preparation. Deterministic mathematical equations model the advection and dispersion of these plumes. However initial plume conditions – height, profile of particle location, volcanic vent parameters – are known only approximately at best, and other features of the governing system such as the windfield are stochastic. These uncertainties make forecasting plume motion difficult. As a result of these uncertainties, ash advisories based on a deterministic approach tend to be conservative, and many times over/under estimate the extent of a plume. This paper presents an end-to-end framework for generating a probabilistic approach to ash plume forecasting. This framework uses an ensemble of solutions, guided by Conjugate Unscented Transform (CUT) method for evaluating expectation integrals. This ensemble is used to construct a polynomial chaos expansion that can be sampled cheaply, to provide a probabilistic model forecast. The CUT method is then combined with a minimum variance condition, to provide a full posterior pdf of the uncertain source parameters, based on observed satellite imagery. The April 2010 eruption of the Eyjafjallajökull volcano in Iceland is employed as a test example. The puff advection/dispersion model is used to hindcast the motion of the ash plume through time, concentrating on the period 14–16 April 2010. Variability in the height and particle loading of that eruption is introduced through a volcano column model called bent. Output uncertainty due to the assumed uncertain input parameter probability distributions, and a probabilistic spatial-temporal estimate of ash presence are computed.

  11. Impact of meteorological clouds on detection of volcanic ash during the Eyjafjallajökull 2010 eruption: A modelling study

    NASA Astrophysics Data System (ADS)

    Kylling, Arve

    2014-05-01

    Volcanic ash is commonly detected by infrared detectors in space using various variations of the reverse absorption technique. The reverse absorption technique explores the brightness temperature difference (BTD) between the 10.8 and 12,0 μm regions of the thermal spectrum. Several factors affect the infrared detection of volcanic ash. For a cloudless sky (no ice nor liquid water clouds), the density, altitude (temperature), particle size and shape of the ash cloud and the surface temperature, impact the infrared volcanic ash signature. In the presence of ice and/or liquid water clouds the BTD between 10.8 and 12.0 μm may change. The effect of ice and liquid water clouds on detection of volcanic ash may not readily be made based on experimental methods due to the inherent problem in comparing overcast and cloudless cases and the need for in-situ ice and liquid water cloud information together with volcanic ash information. Thus a model based approach was adopted. Simulated 10.8 and 12.0 μm Spinning Enhanced Visible and Infrared Imager (SEVIRI) images for the full duration of the Eyjafjallajökull 2010 eruption were used as input to standard reverse absorption ash detection methods. Simulation of images were made both with and without realistic water and ice clouds taken from European Centre for Medium-Range Weather Forecast (ECMWF) analysis. The volcanic ash cloud fields were taken from simulations by the Langrangian particle dispersion Flexpart model. The effect of clouds on detection of volcanic ash was highly variable. For situations with large areas affected by ash, up to 40% of pixels with mass loading > 2g/m2 went undetected due to the presence of water and ice clouds.

  12. The relation between pre-eruptive bubble size distribution, ash particle morphology, and their internal density: Implications to volcanic ash transport and dispersion models

    NASA Astrophysics Data System (ADS)

    Proussevitch, Alexander

    2014-05-01

    Parameterization of volcanic ash transport and dispersion (VATD) models strongly depends on particle morphology and their internal properties. Shape of ash particles affects terminal fall velocities (TFV) and, mostly, dispersion. Internal density combined with particle size has a very strong impact on TFV and ultimately on the rate of ash cloud thinning and particle sedimentation on the ground. Unlike other parameters, internal particle density cannot be measured directly because of the micron scale sizes of fine ash particles, but we demonstrate that it varies greatly depending on the particle size. Small simple type ash particles (fragments of bubble walls, 5-20 micron size) do not contain whole large magmatic bubbles inside and their internal density is almost the same as that of volcanic glass matrix. On the other side, the larger compound type ash particles (>40 microns for silicic fine ashes) always contain some bubbles or the whole spectra of bubble size distribution (BSD), i.e. bubbles of all sizes, bringing their internal density down as compared to simple ash. So, density of the larger ash particles is a function of the void fraction inside them (magmatic bubbles) which, in turn, is controlled by BSD. Volcanic ash is a product of the fragmentation of magmatic foam formed by pre-eruptive bubble population and characterized by BSD. The latter can now be measured from bubble imprints on ash particle surfaces using stereo-scanning electron microscopy (SSEM) and BubbleMaker software developed at UNH, or using traditional high-resolution X-Ray tomography. In this work we present the mathematical and statistical formulation for this problem connecting internal ash density with particle size and BSD, and demonstrate how the TFV of the ash population is affected by variation of particle density.

  13. Airborne studies of the emissions from the volcanic eruptions of mount st. Helens.

    PubMed

    Hobbs, P V; Radke, L F; Eltgroth, M W; Hegg, D A

    1981-02-20

    The concentrations of particles less than 10 micrometers in diameter in the ash emissions from Mount St. Helens have been more than 1000 times greater than those in the ambient air. Mass loadings of particles less than 2 micrometers in diameter were generally several hundred micrograms per cubic meter. In the ash clouds, produced by the large eruption on 18 May 1980, the concentrations of several trace gases generally were low. In other emissions, significant, but variable, concentrations of sulfur gases were measured. The 18 May eruption produced nuées ardentes, lightning flashes, and volcanic hail.

  14. Airborne studies of the emissions from the volcanic eruptions of mount st. Helens.

    PubMed

    Hobbs, P V; Radke, L F; Eltgroth, M W; Hegg, D A

    1981-02-20

    The concentrations of particles less than 10 micrometers in diameter in the ash emissions from Mount St. Helens have been more than 1000 times greater than those in the ambient air. Mass loadings of particles less than 2 micrometers in diameter were generally several hundred micrograms per cubic meter. In the ash clouds, produced by the large eruption on 18 May 1980, the concentrations of several trace gases generally were low. In other emissions, significant, but variable, concentrations of sulfur gases were measured. The 18 May eruption produced nuées ardentes, lightning flashes, and volcanic hail. PMID:17740388

  15. Airborne studies of the emissions from the volcanic eruptions of Mount St. Helens

    SciTech Connect

    Hobbs, P.V.; Radke, L.F.; Eltgroth, M.W.; Hegg, D.A.

    1981-01-01

    The concentrations of particles less than 10 micrometers in diameter in the ash emissions from Mount St. Helens have been more than 1000 times greater than those in the ambient air. Mass loadings of particles less than 2 micrometers in diameter were generally several hundred micrograms per cubic meter. In the ash clouds, produced by the large eruption on 18 May 1980, the concentrations of several trace gases generally were low. In other emissions, significant, but variable, concentrations of sulfur gases were measured. The 18 May eruption produced nuees ardentes, lightning flashes, and volcanic hail.

  16. The effects of volcanic ash on the maceral and chemical composition of the C coal bed, Emery Coal Field, Utah

    USGS Publications Warehouse

    Crowley, S.S.; Stanton, R.W.; Ryer, T.A.

    1989-01-01

    Volcanic ash which fell in the peat swamp that formed the Upper Cretaceous C coal bed (Ferron Sandstone Member of the Mancos Shale, Utah) produced semi-impermeable layers that caused the ponding of surface waters. Coal samples from directly above tonsteins (altered volcanic ash partings) are enriched in desmocollinite, telinite, and detrocollinite, as a result of poorly drained swamp conditions; coal samples from directly below tonsteins are enriched in semifusinite, inertodetrinite, and fusinite, as a result of well-drained conditions. Leaching of the volcanic ash or the incorporation of volcanic ash in peat provided a source for many elements (including Zr, Nb, Th, and Ce) that are enriched in coal samples taken from directly above and below tonsteins. ?? 1989.

  17. Long-range hazard assessment of volcanic ash dispersal for a Plinian eruptive scenario at Popocatépetl volcano (Mexico): implications for civil aviation safety

    USGS Publications Warehouse

    Bonasia, Rosanna; Scaini, Chirara; Capra, Lucia; Nathenson, Manuel; Siebe, Claus; Arana-Salinas, Lilia; Folch, Arnau

    2013-01-01

    Popocatépetl is one of Mexico’s most active volcanoes threatening a densely populated area that includes Mexico City with more than 20 million inhabitants. The destructive potential of this volcano is demonstrated by its Late Pleistocene–Holocene eruptive activity, which has been characterized by recurrent Plinian eruptions of large magnitude, the last two of which destroyed human settlements in pre-Hispanic times. Popocatépetl’s reawakening in 1994 produced a crisis that culminated with the evacuation of two villages on the northeastern flank of the volcano. Shortly after, a monitoring system and a civil protection contingency plan based on a hazard zone map were implemented. The current volcanic hazards map considers the potential occurrence of different volcanic phenomena, including pyroclastic density currents and lahars. However, no quantitative assessment of the tephra hazard, especially related to atmospheric dispersal, has been performed. The presence of airborne volcanic ash at low and jet-cruise atmospheric levels compromises the safety of aircraft operations and forces re-routing of aircraft to prevent encounters with volcanic ash clouds. Given the high number of important airports in the surroundings of Popocatépetl volcano and considering the potential threat posed to civil aviation in Mexico and adjacent regions in case of a Plinian eruption, a hazard assessment for tephra dispersal is required. In this work, we present the first probabilistic tephra dispersal hazard assessment for Popocatépetl volcano. We compute probabilistic hazard maps for critical thresholds of airborne ash concentrations at different flight levels, corresponding to the situation defined in Europe during 2010, and still under discussion. Tephra dispersal mode is performed using the FALL3D numerical model. Probabilistic hazard maps are built for a Plinian eruptive scenario defined on the basis of geological field data for the “Ochre Pumice” Plinian eruption (4965 14C

  18. Long-range hazard assessment of volcanic ash dispersal for a Plinian eruptive scenario at Popocatépetl volcano (Mexico): implications for civil aviation safety

    NASA Astrophysics Data System (ADS)

    Bonasia, Rosanna; Scaini, Chiara; Capra, Lucia; Nathenson, Manuel; Siebe, Claus; Arana-Salinas, Lilia; Folch, Arnau

    2014-01-01

    Popocatépetl is one of Mexico's most active volcanoes threatening a densely populated area that includes Mexico City with more than 20 million inhabitants. The destructive potential of this volcano is demonstrated by its Late Pleistocene-Holocene eruptive activity, which has been characterized by recurrent Plinian eruptions of large magnitude, the last two of which destroyed human settlements in pre-Hispanic times. Popocatépetl's reawakening in 1994 produced a crisis that culminated with the evacuation of two villages on the northeastern flank of the volcano. Shortly after, a monitoring system and a civil protection contingency plan based on a hazard zone map were implemented. The current volcanic hazards map considers the potential occurrence of different volcanic phenomena, including pyroclastic density currents and lahars. However, no quantitative assessment of the tephra hazard, especially related to atmospheric dispersal, has been performed. The presence of airborne volcanic ash at low and jet-cruise atmospheric levels compromises the safety of aircraft operations and forces re-routing of aircraft to prevent encounters with volcanic ash clouds. Given the high number of important airports in the surroundings of Popocatépetl volcano and considering the potential threat posed to civil aviation in Mexico and adjacent regions in case of a Plinian eruption, a hazard assessment for tephra dispersal is required. In this work, we present the first probabilistic tephra dispersal hazard assessment for Popocatépetl volcano. We compute probabilistic hazard maps for critical thresholds of airborne ash concentrations at different flight levels, corresponding to the situation defined in Europe during 2010, and still under discussion. Tephra dispersal mode is performed using the FALL3D numerical model. Probabilistic hazard maps are built for a Plinian eruptive scenario defined on the basis of geological field data for the "Ochre Pumice" Plinian eruption (4965 14C yr BP

  19. Volcanic ash modeling with the online NMMB/BSC-ASH-v1.0: A novel multiscale meteorological model for operational forecast

    NASA Astrophysics Data System (ADS)

    Marti, Alejandro; Folch, Arnau; Jorba, Oriol; Janjic, Zavisa

    2016-04-01

    Volcanic ash forecast became a research priority and a social concern as a consequence of the severe air-traffic disruptions caused by the eruptions of Eyjafjallajökull (Iceland, 2010) and Cordón Caulle (Chile, 2011) volcanoes. Significant progress has taken place in the aftermath of these dramatic events to improve the accuracy of Volcanic Ash Transport and Dispersal (VATD) models and lessen its associated uncertainties. Various levels of uncertainties affect both the quantification of the source term and the driving meteorological inputs. Substantial research is being performed to reduce and quantify epistemic and aleatoric uncertainties affecting the source term. However, uncertainties arising from the driving NWPMs and its coupling offline with the VATDMs have received little attention, even if the experience from other communities (e.g. air quality) highlights the importance of coupling online dispersal and meteorological modeling. Consequently, the need for integrated predictions to represent these two-way feedback effects of the volcanic pollutants on local-scale meteorology is timely. The aim of this talk is to present the NMMB/BSC-ASH, a new on-line multi-scale meteorological model to simulate the emission, transport and deposition of tephra particles released from volcanic eruptions. The model builds on the NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM), which we have modified to account for the specifics of volcanic particles. The final objective in developing the NMMB/BSC-ASH model is two-fold. On one hand, at a research level, we aim at studying the differences between the online/offline approaches and quantify the two-way feedback effect of dense volcanic ash clouds on the radiative budget and regional meteorology. On the other hand, at an operational level, the low computational cost of the NMMB dynamic core suggests that NMMB/BSC-ASH could be applied in a future for more accurate online operational forecasting of volcanic ash clouds.

  20. Recent Developments in Monitoring of Gas and Ash in Volcanic Plumes by Remote Sensing Techniques

    NASA Astrophysics Data System (ADS)

    Arellano, S. R.

    2007-05-01

    Since the 1970s, a growing list of methods for the remote detection and measurement of the composition and dynamics of volcanic plumes has been available for volcanologists and atmospheric scientists. During the last decade of intensive volcanic activity in Ecuador, the use of spectroscopic techniques like COSPEC, DOAS or FTIR has become an important tool in routine volcano monitoring which has resulted in a better understanding of source and path processes related to volcanogenic gas and ash emissions with increasing spatial-temporal resolution capabilities. The most important developments achieved with these techniques include the incorporation of radiative transfer and diffusion modelling in automatic data processing routines. In addition, work is being done to identify and quantitatively estimate the presence of ash by means of UV spectroscopy. The use of these methods allowed us to follow the degassing process of Tungurahua volcano with unprecedented detail. A brief description of these improvements and their results are presented.

  1. Risk, interest groups and the definition of crisis: the case of volcanic ash.

    PubMed

    Hutter, Bridget M; Lloyd-Bostock, Sally

    2013-09-01

    This paper considers a key aspect of the 'risk society' thesis: the belief that we should be able to manage risks and control the world around us. In particular it focuses on the interface between risk and risk events as socially constructed and the insights that 'critical situations' give us into 'the routine and mundane', the otherwise taken for granted assumptions underlying risk regulation. It does this with reference to the events precipitated by the April 2010 volcanic eruption in the Eyjafjallajökull area of Iceland. The resulting cloud of volcanic ash spread across Europe and much of Europe's airspace was closed to civil aviation for six days, with far reaching consequences including huge financial losses for airlines. The social processes of defining and reacting to risk and crisis both reveal and generate dilemmas and challenges in regulation. This paper examines the role of different interest groups in defining risk expectations and thereby redefining the ash crisis as a regulatory crisis.

  2. Growth of volcanic ash aggregates in the presence of liquid water and ice: an experimental approach

    NASA Astrophysics Data System (ADS)

    Van Eaton, Alexa R.; Muirhead, James D.; Wilson, Colin J. N.; Cimarelli, Corrado

    2012-11-01

    Key processes influencing the aggregation of volcanic ash and hydrometeors are examined with an experimental method employing vibratory pan aggregation. Mechanisms of aggregation in the presence of hail and ice pellets, liquid water (≤30 wt%), and mixed water phases are investigated at temperatures of 18 and -20 °C. The experimentally generated aggregates, examined in hand sample, impregnated thin sections, SEM imagery, and X-ray microtomography, closely match natural examples from phreatomagmatic phases of the 27 ka Oruanui and 2010 Eyjafjallajökull eruptions. Laser diffraction particle size analysis of parent ash and aggregates is also used to calculate the first experimentally derived aggregation coefficients that account for changing liquid water contents and subzero temperatures. These indicate that dry conditions (<5-10 wt% liquid) promote strongly size selective collection of sub-63 μm particles into aggregates (given by aggregation coefficients >1). In contrast, liquid-saturated conditions (>15-20 wt% liquid) promote less size selective processes. Crystalline ice was also capable of preferentially selecting volcanic ash <31 μm under liquid-free conditions in a two-stage process of electrostatic attraction followed by ice sintering. However, this did not accumulate more than a monolayer of ash at the ice surface. These quantitative relationships may be used to predict the timescales and characteristics of aggregation, such as aggregate size spectra, densities, and constituent particle size characteristics, when the initial size distribution and water content of a volcanic cloud are known. The presence of an irregularly shaped, millimeter-scale vacuole at the center of natural aggregates was also replicated during interaction of ash and melting ice pellets, followed by sublimation. Fine-grained rims were formed by adding moist aggregates to a dry mixture of sub-31 μm ash, which adhered by electrostatic forces and sparse liquid bridges. From this, we

  3. Case Study on Combined Lidar-Photometer Retrieval of Volcanic ASH Properties

    NASA Astrophysics Data System (ADS)

    Gasteiger, Josef; Wiegner, Matthias; Toledano, Carlos; Groß, Silke; Freudenthaler, Volker

    2016-06-01

    We study the benefit of considering sun-/skyphotometer measurements in a microphysical lidar retrieval. Furthermore, to assess the importance of the aerosol model employed by the retrieval, we compare results obtained using a spheroid aerosol model with results using an advanced aerosol model that considers irregular particle shapes. Preliminary results are shown for the massextinction conversion factor and the single scattering albedo during a measurement case of long-range-transported volcanic ash.

  4. Atmospheric distribution and removal of volcanic ash after the eruption of Kasatochi volcano: A regional model study

    NASA Astrophysics Data System (ADS)

    Langmann, Baerbel; ZakšEk, Klemen; Hort, Matthias

    2010-01-01

    In August 2008, Kasatochi volcano on the Aleutian Islands erupted without much advance warning. Volcanic ash released during this eruption quickly settled out of the atmosphere, mainly into the NE Pacific Ocean. The amount of volcanic ash, as well as the ash fall area and volume into the NE Pacific Ocean, remains speculative, as only a limited number of measurements is available. We used a three-dimensional atmosphere/chemistry-aerosol model to determine the atmospheric distribution of SO2 and volcanic ash and its fallout after the eruption of Kasatochi volcano. In a first step, modeled atmospheric SO2 distributions are compared with satellite data, thereby evaluating the model capabilities to reasonably reproduce atmospheric transport patterns. For modeled volcanic ash mass a considerable reduction of the atmospheric content already occurred by 10 August, the second day after the eruption in accordance with satellite observations. Gravitational settling is the most efficient removal process for volcanic ash mass, exceeding dry and wet deposition by far. Assuming an ash volume of 0.3 km3 released during the eruption of Kasatochi volcano and a median ash particle diameter of 4 μm, the mass of volcanic ash removed at ground within the 0.1 mm isopach covers an area of 7.6 × 105 km2 over the NE Pacific Ocean and makes up 49% of the removed material out of the atmosphere. The amount of ash and that of iron attached to it is sufficient to explain measured seawater CO2 decrease at the ocean station Papa in August 2008 induced by iron fertilization and subsequent phytoplankton production.

  5. Comenditic and pantelleritic ash-flow tuffs from Volcan Las Navajas, Nayarit, Mexico

    SciTech Connect

    Nelson, S.A.; Hebre, J.A.

    1985-01-01

    Two distinctive ash-flow tuffs occur around the base of Volcan Las Navajas, a Pleistocene trachyte - peralkaline rhyolite center located in the northwestern segment of the Mexican Volcanic belt. The lower ash-flow unit is locally up to 65 m thick, is lithic rich and contains pumice blocks of comenditic rhyolite. The unit is not extensively exposed, and thus its areal extent and volume cannot be determined. Its chemical characteristics and stratigraphic relationship to other products erupted from Las Navajas suggest that it is related to the formation of the older of the two calderas which occur on Las Navajas. Unconformably overlying this unwelded ash-flow is a pantelleritic airfall pumice unit which is locally welded. This airfall unit is conformably overlain by a welded as-flow tuff that contains fiamme of pantelleritic composition (72 %SiO/sub 2/, 8% FeO*, 900 ppm Zr, agpaitic index of 1.7) as well as pumice blocks that show evidence of various degrees of mixing between pantellerite and trachyte. This suggests eruption from a chemically zoned magma chamber. This unit is locally up to 20 m thick, although its top has been removed by erosion. It is found on all sides of Las Navajas except on the south where it may be covered by Volcan Sanganguey, a Pleistocene to Recent calc-alkaline volcano. The welded ash-flow has been dated by K - Ar at 0.2+/-0.1 m.y. Stratigraphically and chemically this ash-flow appears to be related to the formation of younger of the two calderas.

  6. The silicification of trees in volcanic ash - An experimental study

    NASA Astrophysics Data System (ADS)

    Ballhaus, Chris; Gee, Carole T.; Bockrath, Conny; Greef, Karin; Mansfeldt, Tim; Rhede, Dieter

    2012-05-01

    The permineralization of trees by pervasive silicification, that is, when forests are buried by volcanic pyroclastics, is simulated with closed-system experiments at 100 °C. The silica source was a ground rhyolitic obsidian glass. The wood samples were coniferous, (Pseudotsuga menziesii, Douglas fir) from the family Pinaceae, and the medium transporting silica from the lithic matrix into the wood tissue was water. Reaction of wood with silica-enriched water shows that wood has a marked affinity to scavenge silica complexes from an aqueous solution and precipitate them on organic surfaces inside the wood cells in the form of opal. Diffusion and advection models are used to estimate how long it may take to permineralize wood logs as massive as those found in petrified forests worldwide. The time scales are on the order of thousands of years.

  7. Volcanic ash and daily mortality in Sweden after the Icelandic volcano eruption of May 2011.

    PubMed

    Oudin, Anna; Carlsen, Hanne K; Forsberg, Bertil; Johansson, Christer

    2013-12-01

    In the aftermath of the Icelandic volcano Grimsvötn's eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24-31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study effects

  8. Volcanic Ash and Daily Mortality in Sweden after the Icelandic Volcano Eruption of May 2011

    PubMed Central

    Oudin, Anna; Carlsen, Hanne K.; Forsberg, Bertil; Johansson, Christer

    2013-01-01

    In the aftermath of the Icelandic volcano Grimsvötn’s eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24–31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study

  9. Volcanic ash and daily mortality in Sweden after the Icelandic volcano eruption of May 2011.

    PubMed

    Oudin, Anna; Carlsen, Hanne K; Forsberg, Bertil; Johansson, Christer

    2013-12-01

    In the aftermath of the Icelandic volcano Grimsvötn's eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24-31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study effects

  10. Inversion Technique for Estimating Emissions of Volcanic Ash from Satellite Imagery

    NASA Astrophysics Data System (ADS)

    Pelley, Rachel; Cooke, Michael; Manning, Alistair; Thomson, David; Witham, Claire; Hort, Matthew

    2014-05-01

    When using dispersion models such as NAME (Numerical Atmospheric-dispersion Modelling Environment) to predict the dispersion of volcanic ash, a source term defining the mass release rate of ash is required. Inversion modelling using observations of the ash plume provides a method of estimating the source term for use in NAME. Our inversion technique makes use of satellite retrievals, calculated using data from the SEVIRI (Spinning Enhanced Visible and Infrared Imager) instrument on-board the MSG (Meteosat Second Generation) satellite, as the ash observations. InTEM (Inversion Technique for Emission Modelling) is the UK Met Office's inversion modelling system. Recently the capability to estimate time and height varying source terms has been implemented and applied to volcanic ash. InTEM uses a probabilistic approach to fit NAME model concentrations to satellite retrievals. This is achieved by applying Bayes Theorem to give a cost function for the source term. Source term profiles with lower costs generate model concentrations that better fit the satellite retrievals. InTEM uses the global optimisation technique, simulated annealing, to find the minimum of the cost function. The use of a probabilistic approach allows the uncertainty in the satellite retrievals to be incorporated into the inversion technique. InTEM makes use of satellite retrievals of both ash column loadings and of cloud free regions. We present a system that allows InTEM to be used during an eruption. The system is automated and can produce source term updates up to four times a day. To allow automation hourly satellite retrievals of ash are routinely produced using conservative detection limits. The conservative detection limits provide good detection of the ash plume while limiting the number of false alarms. Regions which are flagged as ash contaminated or free from cloud (both meteorological and ash) are used in the InTEM system. This approach is shown to improve the concentrations in the

  11. Airborne magnetic mapping of volcanic areas - state-of-the-art and future perspectives

    NASA Astrophysics Data System (ADS)

    Supper, Robert; Paoletti, Valeria; Okuma, Shigeo

    2015-04-01

    Traditionally airborne magnetics surveys in volcanology are used for mapping regional geological features, fault zones and to develop a magnetic model of the volcanic subsurface. Within an Austrian-Italian-Japanese cooperation, several volcanic areas including Mt. Vesuvius, Ischia, Campi Flegreii and Aeolian Islands in Italy and Socorro Island in Mexico were mapped by high-resolution magnetic mapping during the last 15 years. In this paper, general conclusions from this long-term cooperation project on airborne magnetics in volcanic areas will be summarised. Basically the results showed the results from airborne magnetics could be used for three major purposes: 1. Developing a rough model for the magnetisation below the volcano down to several kilometres by applying advanced magnetic inversion algorithms helped to define the possible depth of the current or past magma chamber. Due to the complexity of the subsurface of volcanic areas, inversion of data was much dependent on constraints coming from other geoscientific disciplines. 2. After applying certain steps of reduction (topographic correction, field transformation) and a combination of source selective filtering, important regional structural trends could be derived from the alignment of the residual magnetic anomalies. 3. On the other hand during recent years, research has also focused on repeated measurements of the magnetic field of volcanic areas (differential in respect of time = differential magnetic measurements - DMM) using airborne sensors. Long-term temporal magnetic field variations in active volcanic areas can be caused by a changing size of the magma chamber or a general rise in temperature. This is caused by the fact that magnetization disappears, when a magnetic material is warmed up over a certain temperature (Curie- temperature). In consequence the resulting total magnetic field changes. Therefore, determining areas showing changes in the magnetic field could help to select areas where a

  12. Volcanic ash in surficial sediments of the Kodiak shelf - An indicator of sediment dispersal patterns

    USGS Publications Warehouse

    Hampton, M.A.; Bouma, A.H.; Frost, T.P.; Colburn, I.P.

    1979-01-01

    Surficial sediments of the Kodiak shelf, Gulf of Alaska, contain various amounts of volcanic ash whose physical properties indicate that it originated from the 1912 Katmai eruption. The distribution of ash is related to the shelf physiography and represents redistribution by oceanic circulation rather than the original depositional pattern from the volcanic event. The ash distribution can be used, in conjunction with the distribution of grain sizes, as an indicator of present-day sediment dispersal patterns on the shelf. No significant modern input of sediment is occurring on the Kodiak shelf, which is mostly covered by Pleistocene glacial deposits. Coarse-grained sediments on flat portions of shallow banks apparently are being winnowed, with the removed ash-rich fine material being deposited in shallow depressions on the banks and in three of the four major troughs that cut transversely across the shelf. The other major trough seems to be experiencing a relatively high-energy current regime, with little deposition of fine material. ?? 1979.

  13. Triboelectric Charging of Volcanic Ash from the 2011 Grímsvötn Eruption

    NASA Astrophysics Data System (ADS)

    Houghton, Isobel M. P.; Aplin, Karen L.; Nicoll, Keri A.

    2013-09-01

    The plume from the 2011 eruption of Grímsvötn was highly electrically charged, as shown by the considerable lightning activity measured by the United Kingdom Met Office’s low-frequency lightning detection network. Previous measurements of volcanic plumes have shown that ash particles are electrically charged up to hundreds of kilometers away from the vent, which indicates that the ash continues to charge in the plume [R. G. Harrison, K. A. Nicoll, Z. Ulanowski, and T. A. Mather, Environ. Res. Lett. 5, 024004 (2010)1748-932610.1088/1748-9326/5/2/024004; H. Hatakeyama J. Meteorol. Soc. Jpn. 27, 372 (1949)JMSJAU0026-1165]. In this Letter, we study triboelectric charging of different size fractions of a sample of volcanic ash experimentally. Consistently with previous work, we find that the particle size distribution is a determining factor in the charging. Specifically, our laboratory experiments demonstrate that the normalized span of the particle size distribution plays an important role in the magnitude of charging generated. The influence of the normalized span on plume charging suggests that all ash plumes are likely to be charged, with implications for remote sensing and plume lifetime through scavenging effects.

  14. Triboelectric charging of volcanic ash from the 2011 Grímsvötn eruption.

    PubMed

    Houghton, Isobel M P; Aplin, Karen L; Nicoll, Keri A

    2013-09-13

    The plume from the 2011 eruption of Grímsvötn was highly electrically charged, as shown by the considerable lightning activity measured by the United Kingdom Met Office's low-frequency lightning detection network. Previous measurements of volcanic plumes have shown that ash particles are electrically charged up to hundreds of kilometers away from the vent, which indicates that the ash continues to charge in the plume [R. G. Harrison, K. A. Nicoll, Z. Ulanowski, and T. A. Mather, Environ. Res. Lett. 5, 024004 (2010); H. Hatakeyama J. Meteorol. Soc. Jpn. 27, 372 (1949)]. In this Letter, we study triboelectric charging of different size fractions of a sample of volcanic ash experimentally. Consistently with previous work, we find that the particle size distribution is a determining factor in the charging. Specifically, our laboratory experiments demonstrate that the normalized span of the particle size distribution plays an important role in the magnitude of charging generated. The influence of the normalized span on plume charging suggests that all ash plumes are likely to be charged, with implications for remote sensing and plume lifetime through scavenging effects. PMID:24074123

  15. Volcanic degassing and secondary hydration of volcanic ash and scoria: Implications for paleoaltimetry and paleoclimate studies

    NASA Astrophysics Data System (ADS)

    Seligman, A. N.; Bindeman, I. N.

    2013-12-01

    The use of δD of ash as a reliable recorder of δD (and δ18O) values of paleoprecipitation in paleoclimate and paleoaltimetry research still requires experimental verification and testing. It is currently assumed that ash is deposited with a water content of no significance, and that within a few thousand years it becomes sufficiently (up to 4 wt.% H2O) hydrated, although the rate of hydration and whether or not the initial isotopic signature is held, are not well understood. We report analyses of δD and H2O of distal ash from recent eruptions (1980 Mount St. Helens, 1992 Mt. Spurr, and 1974 Volcán de Fuego) that were collected syneruption, in addition to scoria ranging in age from ~50 to 7300 years old from Klyuchevskoy volcano (Kamchatka, Russia), using the TC/EA - MAT 253 continuous flow system. Natural variability of studied samples in wt.% H2O (δD in ‰), with errors represented as 1 s.d. for the average, for recent ash eruptions, range from 0.1 × 0.07 (-102 × 4.7) for Volcán de Fuego up to 0.7 × 0.10 (-104 × 3.5) for Mount St. Helens. Ash from the Mt. Spurr eruption averaged 0.4 × 0.04 (-109 × 4.0), and we plan to also analyze ash from Mt. Pinatubo. The δD values are consistent with a magmatic degassing trend, where the last remaining water is depleted in deuterium, suggesting ash may be deposited with up to 0.7 wt.% H2O as primary magmatic water. Klyuchevskoy scoria (basaltic andesite) shows a general trend of increasing wt.% H2O with increasing age: the youngest samples (<2.0 ka) have ~0.2 wt.% water (-99 to -109 ‰), which is likely primary magmatic, while the older samples (4.7-7.3 ka) generally have a higher water concentration (~0.3-0.5 wt.%); likely local meteoric water based on δD values that are lower than degassed magmatic δD values and higher water content. The samples between ~2.3 and 3.6 ka (0.1 to 0.4 wt.% water) have variable water concentrations due to variations in porosity and therefore surface area between the different

  16. Thermal Stability of Volcanic Ash versus Turbine Ingestion Test Sands: an Experimental Investigation

    NASA Astrophysics Data System (ADS)

    Cimarelli, C.; Kueppers, U.; Hess, K.; Dingwell, D. B.; Rickerby, D. S.; Madden, P. C.

    2010-12-01

    Volcanic eruptions are an inevitable natural threat. The range of eruptive styles is large and short term fluctuations of explosivity or vent position pose a large risk not necessarily confined to the immediate vicinity of a volcano. Explosive eruptions rather may also affect aviation, infrastructure and climate, regionally as well as globally. The recent eruption of Eyjafjallajökull drastically brought into common awareness how volcanic activity can affect every day’s life and disrupt air traffic. The presence of solid particles in the air ingested in jet turbines may cause harm as it 1) may deposit on surfaces upon being heated up and 2) abrade upon impact. Particles suspended in the atmosphere may have different origins, including volcanic ash, aeolian sand, or incineration residues, each of them having different chemical and physical characteristics. To date, aircraft turbine operability has been investigated - amongst other tests - through the ingestion of sands whose grains have different mineralogical nature. Due to high cooling rates, volcanic ash is usually made up of glass, i.e. an amorphous phase lacking crystallographic order. Glass and crystal behave very differently to heating up. Glass will soften - and accordingly change shape or stick to surfaces - at temperatures as low as 700 °C, depending on the chemical composition. Crystals however need higher melting temperatures; quartz for example has a melting point at around 1700 °C. Accordingly, the effect of ash on the operational reliability of aircraft turbines may not be judged solely based on knowledge commonly derived from mineral sand ingestion testing. In order to investigate the behaviour upon heating, we performed a series of experiments at ten temperature steps between 700 and 1600 °C. We used three different samples: 1) Ash from the explosive phase of Eyjafjallajökull; 2) MIL E-5007C test sand (MTS), and 3) Arizona Test Dust (ATD). MTS and ATD are commonly used for aircraft turbine

  17. An Early-Warning System for Volcanic Ash Dispersal: The MAFALDA Procedure

    NASA Astrophysics Data System (ADS)

    Barsotti, S.; Nannipieri, L.; Neri, A.

    2006-12-01

    Forecasts of the dispersal of volcanic ash is a fundamental goal in order to mitigate its potential impact on urbanized areas and transport routes surrounding explosive volcanoes. To this aim we developed an early- warning procedure named MAFALDA (Modeling And Forecasting Ash Loading and Dispersal in the Atmosphere). Such tool is able to quantitatively forecast the atmospheric concentration of ash as well as the ground deposition as a function of time over a 3D spatial domain.\\The main features of MAFALDA are: (1) the use of the hybrid Lagrangian-Eulerian code VOL-CALPUFF able to describe both the rising column phase and the atmospheric dispersal as a function of weather conditions, (2) the use of high-resolution weather forecasting data, (3) the short execution time that allows to analyse a set of scenarios and (4) the web-based CGI software application (written in Perl programming language) that shows the results in a standard graphical web interface and makes it suitable as an early-warning system during volcanic crises.\\MAFALDA is composed by a computational part that simulates the ash cloud dynamics and a graphical interface for visualizing the modelling results. The computational part includes the codes for elaborating the meteorological data, the dispersal code and the post-processing programs. These produces hourly 2D maps of aerial ash concentration at several vertical levels, extension of "threat" area on air and 2D maps of ash deposit on the ground, in addition to graphs of hourly variations of column height.\\The processed results are available on the web by the graphical interface and the users can choose, by drop-down menu, which data to visualize. \\A first partial application of the procedure has been carried out for Mt. Etna (Italy). In this case, the procedure simulates four volcanological scenarios characterized by different plume intensities and uses 48-hrs weather forecasting data with a resolution of 7 km provided by the Italian Air Force.

  18. Airborne volcanic plume measurements using a FTIR spectrometer, Kilauea volcano, Hawaii

    USGS Publications Warehouse

    McGee, K.A.; Gerlach, T.M.

    1998-01-01

    A prototype closed-path Fourier transform infrared spectrometer system (FTIK), operating from battery power and with a Stirling engine microcooler for detector cooling, was successfully used for airborne measurements of sulfur dioxide at Kilauea volcano. Airborne profiles of the volcanic plume emanating from the erupting Pu'u 'O'o vent on the East Rift of Kilauea revealed levels of nearly 3 ppm SO2 in the core of the plume. An emission rate of 2,160 metric tons per day of sulfur dioxide was calculated from the FTIR data, which agrees closely with simultaneous measurements by a correlation spectrometer (COSPEC). The rapid spatial sampling possible from an airborne platform distinguishes the methodology described here from previous FTIR measurements.

  19. The Volcanic Ash Strategic Initiative Team (VAST) - operational testing activities and exercises

    NASA Astrophysics Data System (ADS)

    Wotawa, Gerhard; Arnold, Delia; Eckhardt, Sabine; Kristiansen, Nina; Maurer, Christian; Prata, Fred; Stohl, Andreas; Zehner, Claus

    2013-04-01

    The project VAST performs its activities within an ESA (European Space Agency) initiative to enhance the use of Earth Observation (EO) data in volcanic ash monitoring and forecasting. The VAST project aims at further exploring the suitability of EO data for such activities and to improve volcanic ash atmospheric transport forecasting services through exercises and demonstration activities in operational environments. Previous to the in-house deployment of the demonstration service, several exercises on operations and communication exchange are needed and first results are presented here. These exercises include technical in-house settings and conceptual planning of the operations with procedure development, volcanic eruptions drills that trigger the acquiring of data and dispersion/forecasting calculations with preliminary estimates of source terms and finally, an international exercise that provides a test case volcanic event to evaluate response times and the usefulness of the different products obtained. Products also include ensemble dispersion forecasts, on one hand multi-input ensembles utilizing the ECMWF EPS system, and on the other hand multi-model ensembles based on different dispersion models driven with different input data. As part of the work, socio-economic aspects need to be taken into account as well. This includes also the identification of best practices on how results can be presented to the stakeholders, including national authorities and policy makers, and the general public.

  20. Ash Redistribution Following a Potential Volcanic Eruption at Yucca Mountain

    NASA Astrophysics Data System (ADS)

    Pelletier, J. D.; Delong, S. B.; Cline, M. L.; Harrington, C. D.; Keating, G.

    2005-12-01

    The redistribution of contaminated tephra by hillslope, fluvial, and pedologic processes is a poorly-constrained but important aspect of evaluating the radiological dose from an unlikely volcanic eruption at Yucca Mountain (YM). To better evaluate this hazard, we developed a spatially-distributed numerical model of tephra redistribution that integrates contaminated tephra from hill slopes and active channels, mixes it with clean sediment in the channel system, distributes it on the fan, and migrates it into the soil column. The model is coupled with an atmospheric dispersion model that predicts the deposition of radioactive waste-contaminated tephra at specified grid points. The redistribution model begins in the upper Fortymile Wash drainage basin where it integrates the tephra deposited on steep slopes and active channel beds within a spatially-distributed framework. The Fortymile Wash drainage basin is the focus of this model because tephra from only this basin reaches the Fortymile Wash alluvial fan by fluvial processes, and it is on this fan where the radiological dose to a hypothetical individual is compared to the regulatory standard (via additional biosphere models). The dilution effect of flood scour, mixing, and re-deposition within the upper basin is modeled using a dilution-mixing model widely used in the contaminant-transport literature. The accuracy of this model is established by comparing the model prediction with tephra concentrations measured in channels draining the Lathrop Wells volcanic center. The model combines the contaminated tephra transported from the upper basin with the tephra deposited directly on the fan as primary fallout. On the Fortymile Wash fan, channels and interchannel-divide areas are divided on the basis of soil-geomorphic mapping according to whether they are Holocene or Pleistocene in age. This approach allows the model to incorporate the effects of channel migration on the fan within the past 10,000 yr. The model treats

  1. ASH REDISTRIBUTION FOLLOWING A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN

    SciTech Connect

    J. Pelletier; S. deLong; M.L. Cline; C. Harrington; G. Keating

    2005-08-29

    The redistribution of contaminated tephra by hillslope, fluvial, and pedologic processes is a poorly-constrained but important aspect of evaluating the radiological dose from an unlikely volcanic eruption at Yucca Mountain (YM). To better evaluate this hazard, we developed a spatially distributed, numerical model of tephra redistribution that integrates contaminated tephra from hill slopes and active channels, mixes it with clean sediment in the channel system, distributes it on the fan, and migrates it into the soil column. The model is coupled with an atmospheric dispersion model that predicts the deposition of radioactive waste-contaminated tephra at specified grid points. The redistribution model begins in the upper Fortymile Wash drainage basin where it integrates the tephra deposited on steep slopes and active channel beds within a GIS framework. The Fortymile Wash drainage basin is the focus of this model because tephra from only this basin reaches the Fortymile Wash alluvial fan by fluvial processes, and it is on this fan where the radiological dose to a hypothetical individual is compared to the regulatory standard (via additional biosphere models). The dilution effect of flood scour, mixing, and re-deposition within the upper basin is modeled using a dilution-mixing model widely used in the contaminant-transport literature. The accuracy of this model is established by comparing the model prediction with tephra concentrations measured in channels draining the Lathrop Wells volcanic center. The model combines the contaminated tephra transported from the upper basin with the tephra deposited directly on the fan as primary fallout. On the Fortymile Wash fan, channels and interchannel-divide areas are divided on the basis of soil-geomorphic mapping according to whether they are Holocene or Pleistocene in age. This approach allows the model to incorporate the effects of channel migration on the fan within the past 10,000 yr. The model treats the redistribution

  2. Optical, microphysical and compositional properties of the Eyjafjallajökull volcanic ash

    NASA Astrophysics Data System (ADS)

    Rocha-Lima, A.; Martins, J. V.; Remer, L. A.; Krotkov, N. A.; Tabacniks, M. H.; Ben-Ami, Y.; Artaxo, P.

    2014-10-01

    Better characterization of the optical properties of aerosol particles are an essential step to improve atmospheric models and satellite remote sensing, reduce uncertainties in predicting particulate transport, and estimate aerosol forcing and climate change. Even natural aerosols such as mineral dust or particles from volcanic eruptions require better characterization in order to define the background conditions from which anthropogenic perturbations emerge. We present a detailed laboratorial study where the spectral optical properties of the ash from the April-May (2010) Eyjafjallajökull volcanic eruption were derived over a broad spectral range, from ultra-violet (UV) to near-infrared (NIR) wavelengths. Samples of the volcanic ash taken on the ground in the vicinity of the volcano were sieved, re-suspended, and collected on filters to separate particle sizes into fine and mixed (coarse and fine) modes. We derived the spectral mass absorption efficiency αabs [m2g-1] for fine and mixed modes particles in the wavelength range from 300 to 2500 nm from measurements of optical reflectance. We retrieved the imaginary part of the complex refractive index Im(m) from αabs, using Mie-Lorenz and T-matrix theories and considering the size distribution of particles obtained by scanning electron microscopy (SEM), and the grain density of the volcanic ash measured as ρ = 2.16 ± 0.13 g cm-3. Im(m) was found to vary from 0.001 to 0.005 in the measured wavelength range. The dependence of the retrieval on the shape considered for the particles were found to be small and within the uncertainties estimated in our calculation. Fine and mixed modes were also analyzed by X-ray fluorescence, exhibiting distinct elemental composition supporting the optical differences we found between the modes. This is a comprehensive and consistent characterization of spectral absorption and imaginary refractive index, density, size, shape and elemental composition of volcanic ash, which will help

  3. Towards fast and routine analyses of volcanic ash morphometry for eruption surveillance applications

    NASA Astrophysics Data System (ADS)

    Leibrandt, Sébastien; Le Pennec, Jean-Luc

    2015-04-01

    The morphometry of volcanic ash produced by explosive eruptions yields ample information on fragmentation processes (e.g. magmatic vs magma-water interactions), and on transport and sedimentation mechanisms. Most previous works on volcanic clast morphometry focused on the Apparent (2D-)Projected shape of ASH grains, here called APASH, to infer processes and eruptive styles. However, textural analyses of ash grains has remained a long and tedious task that made such approaches inappropriate for eruption surveillance duties. In this work we show that new technological advances on automated dispersion of granular materials imaged with a camera-coupled microscope and enhanced computer capabilities enable fast and high resolution image acquisition of thousands of ash grains that solve this limitation. With a morpho-grainsizer designed for such fast and routine measurements we perform a series of APASH analyses on selected ash fractions of tephra deposits from known eruptive styles. We record the size, aspect ratio, circularity and convexity of APASH images and assess resolution, reproducibility, minimum population size, and total analytical duration, and offer recommendations for the reporting of APASH data for interlaboratory comparisons. To avoid fractal geometry concerns, our analyses are carried out at constant size range (250-300 um) and optical magnification (x5) on ~3000 grains/samples collected from homogenized samples. Results from the andesitic 1999-ongoing eruption of Tungurahua volcano (Ecuador) show that ash particles from the moderate 2001 phase are relatively equant and convex in shape, while the stronger 2006 subplinian phase produced ash grains with more elongated, less circular and less convex APASH signatures. Ash grains from a basaltic scoria cone-forming eruption show even more ragged APASH characteristics. Overall, our protocol allows obtaining accurate and reproducible morphometric measurements that reveal subtle variations of the morphological

  4. Towards fast and routine analyses of volcanic ash morphometry for eruption surveillance applications

    NASA Astrophysics Data System (ADS)

    Leibrandt, Sébastien; Le Pennec, Jean-Luc

    2015-05-01

    The morphometry of volcanic ash produced by explosive eruptions yields ample information on fragmentation processes (e.g. magmatic vs magma-water interactions), and on transport and sedimentation mechanisms. Most previous works on volcanic clast morphometry focused on the Apparent (2D-)Projected shape of ASH grains, here termed APASH, to infer processes and eruptive styles. However, textural analyses of ash grains has remained a long and tedious task that made such approaches inappropriate for eruption surveillance duties. In this work we show that new technological advances on automated dispersion of granular materials imaged with a camera-coupled microscope and enhanced computer capabilities enable fast and high resolution image acquisition of thousands of ash grains that resolve this limitation. With a morpho-grainsizer designed for such fast and routine measurements we perform a series of APASH analyses on selected ash fractions of tephra deposits from known eruptive styles. We record the size, aspect ratio, circularity and convexity of APASH images and assess resolution, reproducibility, minimum population size, and total analytical duration, and offer recommendations for the reporting of APASH data for inter-laboratory comparisons. To avoid fractal geometry concerns, our analyses are carried out at constant size range (250-300 μm) and optical magnification (× 5) on ~ 3000 grains per samples collected from homogenized samples. Results from the andesitic 1999-ongoing eruption of Tungurahua volcano (Ecuador) show that ash particles from the moderate 2001 phase are relatively equant and convex in shape, while the stronger 2006 subplinian phase produced ash grains with more elongated, less circular and less convex APASH signatures. Ash grains from a basaltic scoria cone-forming eruption show even more ragged APASH characteristics. Overall, our protocol allows obtaining accurate and reproducible morphometric measurements that reveal subtle variations of the

  5. Geoethics implications in volcanic hazards in Argentina: 24 years of uninterrupted ash-fall

    NASA Astrophysics Data System (ADS)

    Rovere, Elizabeth I.; Violante, Roberto A.; Uber, Silvia M.; Vázquez Herrera, Marcelo

    2016-04-01

    The impact of falling ash reaches all human activities, has effects on human and animal health and is subject to climate and ecosystem of the affected regions. From 1991 until 2015 (24 years), more than 5 eruptions with VEI ≥ 4 in the Southern Volcanic Zone of the Andes occurred; pyroclastic, dust and volcanic ash were deposited (mostly) in Argentina. A recurring situation during eruptions of Hudson (1991), Chaiten (2008), Puyehue-Cordon Caulle (2011) and Calbuco (2015) volcanoes was the accumulation, storage and dump of volcanic ash in depressed areas, beaches, lakes, ditches, storm drains, areas of landfills and transfer stations. The issues that this practice has taken are varied: pollution of aquifers, changes in geomorphology and water courses, usually in "inconspicuous" zones, often in places where there are precarious population or high poverty settlements. The consequences are not immediate but the effects in the mid and long term bring serious drawbacks. On the contrary, a good example of intelligent management of the volcanic impact occurred many years before, during the eruption of Descabezado Grande (Quizapu) volcano in 1932. In that case, and as an example, the city of Trenque Lauquen, located nearly 770 km east of the volcano, decided a communitarian task of collection and burial of the ashfall in small areas, this was a very successful performance. The Quizapu ash plumes transported by the Westerlies (winds) covered with a blanket of volcanic ash the city, ashfall also reached the capital cities of Argentina (Buenos Aires) and Uruguay (Montevideo). Also, the bagging process of volcanic ash with reinforced plastics was an example of Good Practice in the management of the emergency. This allowed the entire affected community to take advantage of this "mineral resource" and contributes to achieving collective and participatory work leading to commercialization and sustainability of these products availed as fertilizers, granular base for ceramics and

  6. Long term exposure to respirable volcanic ash on Montserrat: a time series simulation

    NASA Astrophysics Data System (ADS)

    Hincks, T. K.; Aspinall, W. P.; Baxter, P. J.; Searl, A.; Sparks, R. S. J.; Woo, G.

    2006-01-01

    Frequent ash fallout from long-lived eruptions (with active phases greater than 5 years) may lead to local populations experiencing unacceptably high cumulative exposures to respirable particulate matter. Ash from Montserrat has been shown to contain significant levels of cristobalite and other reactive agents that are associated with an increased risk of developing pneumoconiosis (including silicosis) and other long-term health problems. There are a number of difficulties associated with estimating risks in populations due to uncertain and wide ranging individual exposures, change in behaviour with time and the natural variation in individual response. Present estimates of risk in workers and other population groups are simplifications based on a limited number of exposure measurements taken on Montserrat (1996-1999), and exposure-response curves from epidemiological studies of coal workers exposed to siliceous dust. In this paper we present a method for calculating the long-term cumulative exposure to cristobalite from volcanic ash by Monte Carlo simulation. Code has been written to generate synthetic time series for volcanic activity, rainfall, ash deposition and erosion to give daily ash deposit values and cristobalite fraction at a range of locations. The daily mean personal exposure for PM10 and cristobalite is obtained by sampling from a probability distribution, with distribution parameters dependent on occupation, ground deposit depth and daily weather conditions. Output from multiple runs is processed to calculate the exceedance probability for cumulative exposure over a range of occupation types, locations and exposure periods. Results are interpreted in terms of current occupational standards, and epidemiological exposure-response functions for silicosis are applied to quantify the long-term health risk. Assuming continuing volcanic activity, median risk of silicosis (profusion 1/0 or higher) for an average adult after 20 years continuous exposure is

  7. Linking the IR Christiansen effect to the mean particle size and type of volcanic ash

    NASA Astrophysics Data System (ADS)

    Scollo, Simona; Baratta, Giuseppe A.; Palumbo, Maria Elisabetta; Corradini, Stefano; Leto, Giuseppe; Strazzulla, Giovanni

    2013-04-01

    Infrared transmittance spectra of several volcanic ash samples positioned in the path of a IR beam have been obtained. This technique is widely used in astronomy, in biological applications, in industrial and environmental fields. Nevertheless, in spite of its wide diffusion in several branch of science, up to now only few IR measurements on volcanic ash particles have been carried out in laboratory. In this work, infrared spectroscopy is used to investigate the spectral signature of volcanic ash particles emitted during the 21-24 July 2001 eruption at Mt. Etna, in Italy. A Bruker Equinox-55 FTIR interferometer operating in the range 1.43-16.67 µm is used to analyse the infrared transmittance of ash particles on KBr windows. For every collected spectrum, an image of the volcanic ash particles was recorded in the visible spectral range through the same microscope. These images are then analyzed by standard image analysis software in order to evaluate the main features of the particle shape: the length of the major and minor axes, Feret diameter, area and aspect ratio. We measured the spectrum of only one particle (Single Particle Measurement SPM), the spectrum of a number of particles from two to ten particles (Multi Particle Measurements type 1, MPM1) and of more than a hundred particles (Multi Particle Measurements type 2, MPM2). For SPM, the length of the major and minor axis ranges between 5 and 25 μm and 3.5 and 15 μm, respectively, Feret diameter ranges between 5.5 and 25 μm, while variations of aspect ratio (AR) and area are between 0.5 and 0.95 and between 14 and 285 μm ^ 2. For MPM1 and MPM2, the mean values of the length of the minor and major axis are between 3-4 and 10-17 μm, the Feret diameter between 5 and 20 μm, AR between 0.3 and 0.7 and area between 50 and 400 μm ^ 2. The optical depth spectra as a function of the wave number showed the presence of the Christiansen effect that produces high transmission at a given wavelength in the infrared

  8. Four-year prospective study of the respiratory effects of volcanic ash from Mt. St. Helens

    SciTech Connect

    Buist, A.S.; Vollmer, W.M.; Johnson, L.R.; Bernstein, R.S.; McCamant, L.E.

    1986-04-01

    This report describes the 4-yr follow-up of 712 loggers exposed over an extended period to varying levels of fresh volcanic ash from the 1980 eruptions of Mt. St. Helens. Concerns related to the irritant effect the ash might have on the airways and also to its fibrogenic potential if exposures were intense and continued over many years. Our subjects were divided into 3 groups: high, low, and no exposure. Baseline testing was begun in June 1980, 1 month after the major eruption, and follow-up testing continued on an annual basis through 1984; 88% of the loggers have been tested at least 3 times. Analysis of lung function data showed that a significant, exposure-related decline in FEV1 occurred during the first year after the eruption. The decline was short-lived, however, and by 1984 the differences between exposure groups were no longer significant. Self-reported symptoms of cough, phlegm, and wheeze showed a similar pattern. No ash-related changes were seen in chest roentgenograms taken in 1980 and in 1984. Our findings are consistent with the hypothesis that the inhaled ash caused mucus hypersecretion and/or airway inflammation that reversed when the exposure levels decreased. The ash levels to which the loggers were exposed were low compared with permissible occupational levels for nuisance dusts, but generally higher than the total suspended particulate levels permissible in ambient air.

  9. Modeling volcanic ash resuspension - application to the 14-18 October 2011 outbreak episode in Central Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Folch, A.; Mingari, L.; Osores, M. S.; Collini, E.

    2013-09-01

    Volcanic fallout deposits from the June 2011 Cordón Caulle eruption in Central Patagonia were remobilized in several occasions months after their emplacement. In particular, during 14-18 October 2011, an intense outbreak episode generated huge volcanic clouds that were dispersed across Argentina, causing multiple impacts in the environment, affecting the air quality and disrupting airports. Fine ash particles in volcanic fallout deposits can be resuspended under favourable meteorological conditions, particularly during strong wind episodes in arid environments having low soil moisture and poor vegetation coverage. In opposition to eruption-formed ash clouds, modeling of resuspension-formed ash clouds has received little attention. In consequence, there are no emission schemes specially developed and calibrated for volcanic ash, and no operational product exists to model and forecast the formation and dispersal of resuspension ash clouds. Here we implement three dust emission schemes of increasing complexity in the FALL3D tephra dispersal model and use the 14-18 October 2011 outbreak episode as a model test case. We calibrate the emission schemes and validate the results of the coupled WRF-ARW/FALL3D modeling system using satellite imagery and measurements of visibility (a quantity related to total suspended particle concentration at surface) and particulate matter (PM10) concentration at several meteorological and air quality stations sparse across Argentina and Uruguay. Our final goal is to test the capability of the modeling system to become, in the near future, an operational forecast product for volcanic ash resuspension events.

  10. Comparison of airborne and spaceborne TIR data for studying volcanic geothermal areas

    NASA Astrophysics Data System (ADS)

    Vaughan, R. G.; Heasler, H.; Jaworowski, C.; Bergfeld, D.; Evans, W.

    2015-12-01

    Mapping and quantifying the surface expression of geothermal heat flux in volcanic geothermal areas is important for establishing baseline thermal activity to better detect and understand any future changes that may be related to hydrothermal or volcanic processes, or human activities. Volcanic geothermal areas are often too large and inaccessible for only field-based thermal monitoring, so thermal infrared (TIR) remote sensing tools are also used. High resolution (sub-meter) airborne TIR imagery can be used for detailed, quantitative analyses of small, subtle geothermal features. Airborne data acquisitions have the advantage of being able to be acquired under ideal conditions (e.g., predawn, cloud-free), but the disadvantage of high costs - thus precluding high-frequency monitoring. Satellite-based TIR data from the Landsat 8 platform are freely available and can be acquired regularly for change detection, but are acquired with coarser spatial resolution (e.g., 100-m pixels), and thus are not as sensitive to subtle thermal characteristics. Two geothermal areas with clear, nighttime TIR data from nearly concurrent (within days) airborne and spaceborne instruments were investigated: Norris Geyser Basin in Yellowstone National Park, WY; and the Casa Diablo geothermal field, near Mammoth Lakes, CA. At Norris Geyser Basin, the area covered by high-resolution airborne TIR imagery is almost entirely geothermally heated ground, with hundreds of fumaroles, hot springs, and thermal drainages - although some non-geothermal background is exposed. With the coarser resolution Landsat 8 data, there are thermal variations within the smaller area covered by the airborne data, but the entire area appears to be thermally anomalous with respect to the non-geothermal background outside the basin. In the geothermal field around the Casa Diablo geothermal site, there are numerous, small areas of geothermal heating that are clearly distinguishable above the background by the high

  11. Sensitivity of dispersion model forecasts of volcanic ash clouds to the physical characteristics of the particles

    NASA Astrophysics Data System (ADS)

    Beckett, F. M.; Witham, C. S.; Hort, M. C.; Stevenson, J. A.; Bonadonna, C.; Millington, S. C.

    2015-11-01

    This study examines the sensitivity of atmospheric dispersion model forecasts of volcanic ash clouds to the physical characteristics assigned to the particles. We show that the particle size distribution (PSD) used to initialise a dispersion model has a significant impact on the forecast of the mass loading of the ash particles in the atmosphere. This is because the modeled fall velocity of the particles is sensitive to the particle diameter. Forecasts of the long-range transport of the ash cloud consider particles with diameters between 0.1 μm and 100 μm. The fall velocity of particles with diameter 100 μm is over 5 orders of magnitude greater than a particle with diameter 0.1 μm, and 30 μm particles fall 88% slower and travel up to 5× further than a 100 μm particle. Identifying the PSD of the ash cloud at the source, which is required to initialise a model, is difficult. Further, aggregation processes are currently not explicitly modeled in operational dispersion models due to the high computational costs associated with aggregation schemes. We show that using a modified total grain size distribution (TGSD) that effectively accounts for aggregation processes improves the modeled PSD of the ash cloud and deposits from the eruption of Eyjafjallajökull in 2010. Knowledge of the TGSD of an eruption is therefore critical for reducing uncertainty in quantitative forecasts of ash cloud dispersion. The density and shape assigned to the model particles have a lesser but still significant impact on the calculated fall velocity. Accounting for the density distribution and sphericity of ash from the eruption of Eyjafjallajökull in 2010, modeled particles can travel up to 84% further than particles with default particle characteristics that assume the particles are spherical and have a fixed density.

  12. Revealing the aerosol radiative impact of volcanic ash on synoptic time scales

    NASA Astrophysics Data System (ADS)

    Walter, Carolin; Rieger, Daniel; Gasch, Philipp; Förstner, Jochen; Vogel, Bernhard

    2016-04-01

    Including the interactions of aerosols with radiation in weather forecast models often leads to perturbations of the temperature field even at locations not directly influenced by the regarded aerosols. They arise out of signals propagating with the speed of sound leading to abrupt changes in cloud cover. The temperature perturbations due to these changes hamper the quantification of the aerosol radiative impact as they can appear in the same order of magnitude. In order to reveal the aerosol radiative impact on synoptic time scales we introduce a new method to separate the aerosol induced temperature effect from atmospheric perturbations. We simulated the impact of volcanic ash aerosol on radiation with the new global to regional scale modelling system ICON-ART (ICOsahedral Nonhydrostatic - Aerosols and Reactive Trace gases; Rieger et al., 2015). Within ICON-ART the radiative fluxes and cooling rates are calculated with the RRTM (Rapid Radiative Transfer Model; Mlawer et al., 1997) for 30 longwave and shortwave bands. To determine the optical properties of the prognostic ash aerosol, Mie calculations were conducted for a compilation of ash refractive indices. We obtain a significant change in 2 m temperature of up to several Kelvin for the Puyehue-Cordon Caulle eruption in 2011. In addition to the temperature effect the atmospheric stability is modified and as a consequence the ash concentrations. The temperature effect during the Eyjafjallajökull eruption in 2010 over Europe is much less pronounced. Nevertheless, we are able to show the impact of volcanic ash on the state of the atmosphere by this eruption.

  13. A physico-chemical assessment of the health hazard of Mt. Vesuvius volcanic ash

    NASA Astrophysics Data System (ADS)

    Horwell, C. J.; Stannett, G. W.; Andronico, D.; Bertagnini, A.; Fenoglio, I.; Fubini, B.; Le Blond, J. S.; Williamson, B. J.

    2010-04-01

    Mt. Vesuvius, Italy, is regarded as one of the world's most dangerous volcanoes because of the potential for vast numbers of people to be affected by the renewal of volcanic activity; more than 600 000 people live within 10 km of the summit alone. Vesuvius has been quiescent since 1944 and with continued dormancy, the more likely it is that the next eruption will be explosive. At that point, wide-spread concern is likely over the potential health hazard of the ash, away from the zone of primary volcanic hazards. Analyses of the mineralogical and geochemical characteristics of ash provide us with critical information on the potential toxicity of the particles, for example, whether particles are sufficiently small to enter the lungs and whether the particles have reactive properties which could trigger disease. Rapid assessment of these characteristics allows real-time decision making on hazard mitigation issues (e.g. distribution of dust masks) and allows considered judgement on whether to embark on major medical/toxicological studies. The study presented here is the first time that the potential respiratory health hazard of ash from Vesuvius volcano has been considered and allows planning for future eruption scenarios. Twenty-one ash samples, representing the range of eruption styles at Vesuvius, were collected and analysed. The results demonstrate that the physical processes of fragmentation play an important role in determining the grain size and, therefore, hazard, of the ash. Here, the finest samples derive from the interaction of magma and water during the final, phreatomagmatic phases of plinian and subplinian eruptions (˜ 16 vol.% <4 µm material), while the low-intensity explosivity activity, associated with lava effusion, produces coarse ash posing a lesser hazard. The quantity of material found in the different health-pertinent fractions is strongly correlated, allowing prediction of these fractions where only coarser sieve data are available. Since

  14. Spain as an emergency air traffic hub during volcanic air fall events? Evidence of past volcanic ash air fall over Europe during the late Pleistocene

    NASA Astrophysics Data System (ADS)

    Hardiman, Mark; Lane, Christine; Blockley, Simon P. E.; Moreno, Ana; Valero-Garcés, Blas; Ortiz, José E.; Torres, Trino; Lowe, John J.; Menzies, Martin A.

    2010-05-01

    Past volcanic eruptions often leave visible ash layers in the geological record, for example in marine or lake sedimentary sequences. Recent developments, however, have shown that non-visible volcanic ash layers are also commonly preserved in sedimentary deposits. These augment the record of past volcanic events by demonstrating that past ash dispersals have been more numerous and widely disseminated in Europe than previously appreciated. The dispersal ‘footprints' of some large late Pleistocene European eruptions are examined here in the light of the recent Eyjafjallajökull eruption. For example, the Vedde Ash which was erupted from Iceland around 12 thousand years ago, delivered distal (and non-visible) glass deposits as far south as Switzerland and as far east as the Ural Mountains in Russia, with an overall European distribution remarkably similar to the dominant tracks of the recent Eyjafjallajökull plumes. The Eyjafjallajökull eruption has demonstrated that relatively small amounts of distal volcanic ash in the atmosphere can seriously disrupt aviation activity, with attendant economic and other consequences. It has raised fundamental questions about the likelihood of larger or more prolonged volcanic activity in the near future, and the possibility of even more serious consequences than those experienced recently. Given that there are several other volcanic centres that could cause such disruption in Europe (e.g. Campania and other volcanic centres in Italy; Aegean volcanoes), a key question is whether there are parts of Europe less prone to ash plumes and which could therefore operate as emergency air traffic hubs during times of ash dispersal. Although not generated to answer this question, the recent geological record might provide a basis for seeking the answer. For example, four palaeo-records covering the time frame of 8 - 40 Ka BP that are geographically distributed across Spain have been examined for non-visible distal ash content. All four have

  15. Uncertainty propagation analysis applied to volcanic ash dispersal at Mt. Etna by using a Lagrangian model

    NASA Astrophysics Data System (ADS)

    de'Michieli Vitturi, Mattia; Pardini, Federica; Spanu, Antonio; Neri, Augusto; Vittoria Salvetti, Maria

    2015-04-01

    Volcanic ash clouds represent a major hazard for populations living nearby volcanic centers producing a risk for humans and a potential threat to crops, ground infrastructures, and aviation traffic. Lagrangian particle dispersal models are commonly used for tracking ash particles emitted from volcanic plumes and transported under the action of atmospheric wind fields. In this work, we present the results of an uncertainty propagation analysis applied to volcanic ash dispersal from weak plumes with specific focus on the uncertainties related to the grain-size distribution of the mixture. To this aim, the Eulerian fully compressible mesoscale non-hydrostatic model WRF was used to generate the driving wind, representative of the atmospheric conditions occurring during the event of November 24, 2006 at Mt. Etna. Then, the Lagrangian particle model LPAC (de' Michieli Vitturi et al., JGR 2010) was used to simulate the transport of mass particles under the action of atmospheric conditions. The particle motion equations were derived by expressing the Lagrangian particle acceleration as the sum of the forces acting along its trajectory, with drag forces calculated as a function of particle diameter, density, shape and Reynolds number. The simulations were representative of weak plume events of Mt. Etna and aimed to quantify the effect on the dispersal process of the uncertainty in the particle sphericity and in the mean and variance of a log-normal distribution function describing the grain-size of ash particles released from the eruptive column. In order to analyze the sensitivity of particle dispersal to these uncertain parameters with a reasonable number of simulations, and therefore with affordable computational costs, response surfaces in the parameter space were built by using the generalized polynomial chaos technique. The uncertainty analysis allowed to quantify the most probable values, as well as their pdf, of the number of particles as well as of the mean and

  16. Volcanic ash layers in the long TALDICE ice core (East Antarctic plateau)

    NASA Astrophysics Data System (ADS)

    Narcisi, B.; Petit, J. R.; Chappellaz, J.; Buiron, D.

    2009-04-01

    The TALDICE (TALos Dome Ice CorE) European project aims to provide a continuous and detailed climatic and environmental record of the last two glacial cycles through the study of a deep ice core from the Antarctic coastal site of Talos Dome (72°49' S, 159°11' E, 2315 m). Drilling was completed in December 2007 at the depth of 1620 m. Tephra studies in the TALDICE record can contribute to solve correlation and dating issues, as well as to provide new insight into the Late Quaternary explosive volcanic history of tephra source regions. A hundred of visible volcanic events have been detected so far during core logging; most likely further tephra layers invisible to the naked eye will be discovered by grain size analysis for continental dust studies. We have characterised 35 tephra layers from the uppermost 1300 m of the TALDICE ice core, spanning the last 70 kyr. Grain size and ash concentration measurements were performed using a Coulter counter set up in a dust-free clean room. Volcanic ash particles were studied under a scanning electron microscope and were characterised for their major element composition with an electron microprobe. Volcanic grains in the studied samples are up to 150 µm large and mainly consist of pristine glass fragments showing various morphologies. The glass geochemical composition is invariably alkaline, indicating provenance from Antarctic within-plate volcanoes. Both coarse particle size and chemical signature of the studied samples strongly suggest that are derived from vents of the McMurdo volcanic province, located ca. 200 km from Talos Dome. A few studied layers contain coarse feldspar grains in addition to glass particles and could be suitable for radiometric dating. Our study provides the first well-dated tephrostratigraphy for the northern Victoria Land region along with initial tephrostratigraphic links with other Antarctic climatic records.

  17. An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash.

    PubMed

    Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

    2013-01-01

    Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s(-1) in each storm with gusts up to 38.7 m s(-1). Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m(-1) during the most intense storm event with a rate of 1,440 kg m(-1) hr(-1) for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions. PMID:23409248

  18. Neural-Network Approach to Hyperspectral Data Analysis for Volcanic Ash Clouds Monitoring

    NASA Astrophysics Data System (ADS)

    Piscini, Alessandro; Ventress, Lucy; Carboni, Elisa; Granger, Roy Gordon; Del Frate, Fabio

    2015-06-01

    In this study three artificial neural networks (ANN) were implemented in order to emulate a retrieval model and to estimate the ash Aerosol optical Depth (AOD), particle effective radius (reff) and cloud height from volcanic eruption using hyperspectral remotely sensed data. ANNs were trained using a selection of Infrared Atmospheric Sounding Interferometer (IASI) channels in Thermal Infrared (TIR) as inputs, and the corresponding ash parameters retrieved obtained using the Oxford retrievals as target outputs. The retrieval is demonstrated for the eruption of the Eyjafjallajokull volcano (Iceland) occurred in 2010. The results of validation provided root mean square error (RMSE) values between neural network outputs and targets lower than standard deviation (STD) of corresponding target outputs, therefore demonstrating the feasibility to estimate volcanic ash parameters using an ANN approach, and its importance in near real time monitoring activities, owing to its fast application. A high accuracy has been achieved for reff and cloud height estimation, while a decreasing in accuracy was obtained when applying the NN approach for AOD estimation, in particular for those values not well characterized during NN training phase.

  19. An extreme wind erosion event of the fresh Eyjafjallajökull 2010 volcanic ash

    PubMed Central

    Arnalds, Olafur; Thorarinsdottir, Elin Fjola; Thorsson, Johann; Waldhauserova, Pavla Dagsson; Agustsdottir, Anna Maria

    2013-01-01

    Volcanic eruptions can generate widespread deposits of ash that are subsequently subjected to erosive forces which causes detrimental effects on ecosystems. We measured wind erosion of the freshly deposited Eyjafjallajökull ash at a field site the first summer after the 2010 eruption. Over 30 wind erosion events occurred (June-October) at wind speeds > 10 m s−1 in each storm with gusts up to 38.7 m s−1. Surface transport over one m wide transect (surface to 150 cm height) reached > 11,800 kg m−1 during the most intense storm event with a rate of 1,440 kg m−1 hr−1 for about 6½ hrs. This storm is among the most extreme wind erosion events recorded on Earth. The Eyjafjallajökull wind erosion storms caused dust emissions extending several hundred km from the volcano affecting both air quality and ecosystems showing how wind erosion of freshly deposited ash prolongs impacts of volcanic eruptions. PMID:23409248

  20. Iron dissolution from volcanic ash in low-pH atmospheric water: a key control on volcanic iron input to the surface ocean?

    NASA Astrophysics Data System (ADS)

    Maters, E.; Delmelle, P.; Ayris, P. M.; Opfergelt, S.

    2012-12-01

    A low concentration of dissolved iron (Fe) limits phytoplankton growth in approximately 30% of the ocean. The input of soluble Fe to these High-Nutrient Low-Chlorophyll (HNLC) regions has the potential to boost primary production and thereby enhance the drawdown of atmospheric carbon dioxide (CO2). Over geological timescales, volcanic activity may alter the flux of Fe to the surface ocean and so contribute to modulating atmospheric CO2 concentrations, ultimately impacting the global climate. Ocean Fe fertilisation has also recently been found to contribute to century-scale carbon sequestration via the export of biomass to the seafloor. Atmospherically deposited volcanic ash is now increasingly seen as an intermittent source of Fe to the surface ocean. Understanding the process of Fe release from ash in solution is key for assessing the potential for ash, particularly that produced by large but rare explosive eruptions or during sustained periods of intense volcanism, to fertilise the marine environment. Previous studies have measured the release of Fe from ash in near-neutral pH solution, but the influence of interaction between ash and acidic cloud- or rainwater during transport on Fe release is poorly understood. In this study, seven volcanic ash samples ranging from tephrite to rhyolite (49-74 wt.% SiO2) were leached in pH 1 H2SO4 in batch reactors for 336 h, at a 1:500 ash-to-solution ratio, to investigate Fe release under acidic conditions. Major element concentrations were measured by inductively coupled plasma- atomic emission spectroscopy (ICP-AES) across a time series of ash leachates. Changes in ash surface composition induced by contact with acid solution were assessed by X-ray photoelectron spectroscopy (XPS). The Fe2+/Fe3+ ratio in ash leachates was also determined for the first time, using the Ferrozine method. The ash samples released 42 to 411 μmol m-2 of Fe over 336 h of leaching. High initial Fe release rates (>1 μmol m-2 h-1) sustained for up

  1. A model sensitivity study of the impact of clouds on satellite detection and retrieval of volcanic ash

    NASA Astrophysics Data System (ADS)

    Kylling, A.; Kristiansen, N.; Stohl, A.; Buras-Schnell, R.; Emde, C.; Gasteiger, J.

    2015-05-01

    Volcanic ash is commonly observed by infrared detectors on board Earth-orbiting satellites. In the presence of ice and/or liquid-water clouds, the detected volcanic ash signature may be altered. In this paper the sensitivity of detection and retrieval of volcanic ash to the presence of ice and liquid-water clouds was quantified by simulating synthetic equivalents to satellite infrared images with a 3-D radiative transfer model. The sensitivity study was made for the two recent eruptions of Eyjafjallajökull (2010) and Grímsvötn (2011) using realistic water and ice clouds and volcanic ash clouds. The water and ice clouds were taken from European Centre for Medium-Range Weather Forecast (ECMWF) analysis data and the volcanic ash cloud fields from simulations by the Lagrangian particle dispersion model FLEXPART. The radiative transfer simulations were made both with and without ice and liquid-water clouds for the geometry and channels of the Spinning Enhanced Visible and Infrared Imager (SEVIRI). The synthetic SEVIRI images were used as input to standard reverse absorption ash detection and retrieval methods. Ice and liquid-water clouds were on average found to reduce the number of detected ash-affected pixels by 6-12%. However, the effect was highly variable and for individual scenes up to 40% of pixels with mass loading >0.2 g m-2 could not be detected due to the presence of water and ice clouds. For coincident pixels, i.e. pixels where ash was both present in the FLEXPART (hereafter referred to as "Flexpart") simulation and detected by the algorithm, the presence of clouds overall increased the retrieved mean mass loading for the Eyjafjallajökull (2010) eruption by about 13%, while for the Grímsvötn (2011) eruption ash-mass loadings the effect was a 4% decrease of the retrieved ash-mass loading. However, larger differences were seen between scenes (standard deviations of ±30 and ±20% for Eyjafjallajökull and Grímsvötn, respectively) and even larger ones

  2. Volcanic-ash hazard to aviation during the 2003 2004 eruptive activity of Anatahan volcano, Commonwealth of the Northern Mariana Islands

    NASA Astrophysics Data System (ADS)

    Guffanti, Marianne; Ewert, John W.; Gallina, Gregory M.; Bluth, Gregg J. S.; Swanson, Grace L.

    2005-08-01

    Within the Commonwealth of the Northern Mariana Islands (CNMI), Anatahan is one of nine active subaerial volcanoes that pose hazards to major air-traffic routes from airborne volcanic ash. The 2003-2004 eruptive activity of Anatahan volcano affected the region's aviation operations for 3 days in May 2003. On the first day of the eruption (10 May 2003), two international flights from Saipan to Japan were cancelled, and several flights implemented ash-avoidance procedures. On 13 May 2003, a high-altitude flight through volcanic gas was reported, with no perceptible damage to the aircraft. TOMS and MODIS analysis of satellite data strongly suggests that no significant ash and only minor amounts of SO 2 were involved in the incident, consistent with crew observations. On 23 May 2003, airport operations were disrupted when tropical-cyclone winds dispersed ash to the south, dusting Saipan with light ashfall and causing flight cancellations there and at Guam 320 km south of the volcano. Operational (near-real-time) monitoring of ash clouds produced by Anatahan has been conducted since the first day of the eruption on 10 May 2003 by the Washington Volcanic Ash Advisory Center (VAAC). The VAAC was among the first groups outside of the immediate area of the volcano to detect and report on the unexpected eruption of Anatahan. After being contacted about an unusual cloud by National Weather Service forecasters in Guam at 1235 UTC on 10 May 2003, the VAAC analyzed GOES 9 images, confirming Anatahan as the likely source of an ash cloud and estimating that the eruption began at about 0730 UTC. The VAAC issued its first Volcanic Ash Advisory for Anatahan at 1300 UTC on 10 May 2003 more than 5 h after the start of the eruption, the delay reflecting the difficulty of detecting and confirming a surprise eruption at a remote volcano with no in situ real-time geophysical monitoring. The initial eruption plume reached 10.7-13.4 km (35,000-44,000 ft), well into jet cruise altitudes

  3. Volcanic-ash hazard to aviation during the 2003-2004 eruptive activity of Anatahan volcano, Commonwealth of the Northern Mariana Islands

    USGS Publications Warehouse

    Guffanti, M.; Ewert, J.W.; Gallina, G.M.; Bluth, G.J.S.; Swanson, G.L.

    2005-01-01

    Within the Commonwealth of the Northern Mariana Islands (CNMI), Anatahan is one of nine active subaerial volcanoes that pose hazards to major air-traffic routes from airborne volcanic ash. The 2003-2004 eruptive activity of Anatahan volcano affected the region's aviation operations for 3 days in May 2003. On the first day of the eruption (10 May 2003), two international flights from Saipan to Japan were cancelled, and several flights implemented ash-avoidance procedures. On 13 May 2003, a high-altitude flight through volcanic gas was reported, with no perceptible damage to the aircraft. TOMS and MODIS analysis of satellite data strongly suggests that no significant ash and only minor amounts of SO2 were involved in the incident, consistent with crew observations. On 23 May 2003, airport operations were disrupted when tropical-cyclone winds dispersed ash to the south, dusting Saipan with light ashfall and causing flight cancellations there and at Guam 320 km south of the volcano. Operational (near-real-time) monitoring of ash clouds produced by Anatahan has been conducted since the first day of the eruption on 10 May 2003 by the Washington Volcanic Ash Advisory Center (VAAC). The VAAC was among the first groups outside of the immediate area of the volcano to detect and report on the unexpected eruption of Anatahan. After being contacted about an unusual cloud by National Weather Service forecasters in Guam at 1235 UTC on 10 May 2003, the VAAC analyzed GOES 9 images, confirming Anatahan as the likely source of an ash cloud and estimating that the eruption began at about 0730 UTC. The VAAC issued its first Volcanic Ash Advisory for Anatahan at 1300 UTC on 10 May 2003 more than 5 h after the start of the eruption, the delay reflecting the difficulty of detecting and confirming a surprise eruption at a remote volcano with no in situ real-time geophysical monitoring. The initial eruption plume reached 10.7-13.4 km (35,000-44,000 ft), well into jet cruise altitudes

  4. Oxidation of shallow conduit magma: Insight from μ-XANES analysis on volcanic ash particle

    NASA Astrophysics Data System (ADS)

    Miwa, T.; Ishibashi, H.; Iguchi, M.

    2014-12-01

    Redox state of magma is important to understand dynamics of volcanic eruptions because magma properties such as composition of degassed volatiles, stability field of minerals, and rheology of magma depend on redox state. To evaluate redox state of magma, Fe3+/ΣFe ratio [= Fe3+/( Fe3++ Fe2+)] of volcanic glass has been measured non-destructively by Fe-K edge μ-XANES (micro X-ray Absorption Near Edge Structure) spectroscopy (e.g., Cottrell and Kelly, 2011). We performed textural, compositional, and Fe-K edge μ-XANES analyses on volcanic ash to infer oxidation process of magma at shallow conduit during eruption at Bromo Volcano, Indonesia. The volcanic ash particles were collected in 24th March 2011 by real-time sampling from ongoing activity. The activity was characterized by strombolian eruption showing magma head ascended to near the ground surface. The ash sample contains two type of volcanic glasses named as Brown and Black glasses (BrG and BlG), based on their color. Textual analysis shows microlite crystallinities are same in the two type of glasses, ranging from 0 to 3 vol.%. EPMA analyses show that all of the glasses have almost identical andesitic composition with SiO2 = 60 wt.%. In contrast, Fe-K edge μ-XANES spectra with the analytical method by Ishibashi et al. (in prep) demonstrate that BrG (Fe3+/ΣFe = 0.20-0.26) is more oxidized than BlG (Fe3+/ΣFe = 0.32-0.60). From combination of the glass composition, the measured Fe3+/ΣFe ratio and 1060 degree C of temperature (Kress and Carmichael, 1991), the oxygen fugacities are estimated to be NNO and NNO+4 for BrG and BlG, respectively. The volcanic glasses preserve syn-eruptive physicochemical conditions by rapid quenching due to their small size ranging from 125 to 250 μm. Our results demonstrate that BrG and BlG magmas are textually and chemically identical but their redox conditions are different at the eruption. The oxidation of magma can be caused by following two processes; 1) diffusive transport

  5. Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards: Part I. Validation of satellite-derived Volcanic Ash Levels.

    NASA Astrophysics Data System (ADS)

    Koukouli, MariLiza; Balis, Dimitris; Simopoulos, Spiros; Siomos, Nikos; Clarisse, Lieven; Carboni, Elisa; Wang, Ping; Siddans, Richard; Marenco, Franco; Mona, Lucia; Pappalardo, Gelsomina; Spinetti, Claudia; Theys, Nicolas; Tampellini, Lucia; Zehner, Claus

    2014-05-01

    The 2010 eruption of the Icelandic volcano Eyjafjallajökull attracted the attention of the public and the scientific community to the vulnerability of the European airspace to volcanic eruptions. Major disruptions in European air traffic were observed for several weeks surrounding the two eruptive episodes, which had a strong impact on the everyday life of many Europeans as well as a noticable economic loss of around 2-3 billion Euros in total. The eruptions made obvious that the decision-making bodies were not informed properly and timely about the commercial aircraft capabilities to ash-leaden air, and that the ash monitoring and prediction potential is rather limited. After the Eyjafjallajökull eruptions new guidelines for aviation, changing from zero tolerance to newly established ash threshold values, were introduced. Within this spirit, the European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, called for the creation of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction . This system is based on improved and dedicated satellite-derived ash plume and sulphur dioxide level assessments, as well as an extensive validation using auxiliary satellite, aircraft and ground-based measurements. The validation of volcanic ash levels extracted from the sensors GOME-2/MetopA, IASI/MetopA and MODIS/Terra and MODIS/Aqua is presented in this work with emphasis on the ash plume height and ash optical depth levels. Co-located aircraft flights, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation [CALIPSO] soundings and well as European Aerosol Research Lidar Network [EARLINET] measurements were compared to the different satellite estimates for the those two eruptive episodes. The validation results are extremely promising with most satellite sensors performing quite well and within the estimated uncertainties compared to the comparative datasets. The findings are

  6. Data on Holocene Tephra (Volcanic Ash) Deposits in the Alaska Peninsula and Lower Cook Inlet Region of the Aleutian Volcanic Arc, Alaska

    USGS Publications Warehouse

    Riehle, J.R.; Meyer, C.E.; Miyaoka, Ronny T.

    1999-01-01

    Introduction This site provides information about the number, thickness, and grainsize of Holocene volcanic ash deposits at 50 localities in the eastern Aleutian volcanic arc. In addition, the major-element compositions of the glasses separated from more than 350 samples of tephra from these localities, determined by electron microprobe, are presented as a basis for correlating samples. Where known with reasonable certainty, the source of an analyzed sample is also identified for use in comparative studies of magma chemistry.

  7. An Appalachian isochron: a kaolinized Carboniferous air-fall volcanic-ash deposit (tonstein)

    USGS Publications Warehouse

    Lyons, P.C.

    1992-01-01

    The Fire Clay tonstein is a kaolinized, airfall volcanic ash bed that was deposited in a widespread late Carboniferous peat-forming mire. Eleven samples from Kentucky and West Virginia, spanning a distance of 200km, and two samples from Tennessee and Virginia indicate a characteristic mineralogical signature. A high-silica alkalic rhyolitic source is suggested by the geochemistry of immobile elements and by electron-probe analyses of glass inclusions. 40Ar/39Ar sanidine plateau dating indicates an age of 312??1 Ma for the Fire Clay tonstein, which is consistent with previous 40Ar/39Ar dates for this tonstein. A new isopachous map of the Fire Clay ash-fall deposit indicates an area of 37 000km2 and a probable source to the present-day southwest. -from Authors

  8. Explosions of andesitic volcanoes in Kamchatka and danger of volcanic ash clouds to aviation

    NASA Astrophysics Data System (ADS)

    Gordeev, E. I.; Girina, O. A.; Neal, C. A.

    2010-12-01

    There are 30 active volcanoes in Kamchatka and 4 of them continuously active. The explosions of andesitic volcanoes (Bezymianny and Sheveluch) produce strong and fast ash plumes, which can rich high altitude (up to 15 km) in short time. Bezymianny and Sheveluch are the most active volcanoes of Kamchatka. A growth of the lava dome of Bezymianny into the explosive crater continues from 1956 till present. Nine strong explosive eruptions of the volcano associated with the dome-building activity occurred for last 5 years in: 2005, January 11 and November 30; 2006, May 09 and December 24; 2007, May 11 and October 14-15; 2008, August 19; 2009, December 16-17 and 2010, May 31. Since 1980, a lava dome of Sheveluch has being growing at the bottom of the explosive crater, which has formed as the result of the catastrophic eruption in 1964. Strong explosive eruptions of the volcano associated with the dome-building activity occurred in: 1993, April 22; 2001, May 19-21; 2004, May 09; 2005, February 27 and September 22; 2006, December 25-26; 2007, March 29 and December 19; 2009, April 26-28 and September 10-11. Strong explosive eruption of andesitic volcanoes is the most dangerous for aircraft because in a few hours or days in the atmosphere and the stratosphere can produce about several cubic kilometers of volcanic ash and aerosols. Volcanic ash is an extremely abrasive, as it consists of acute-angled rock fragments and volcanic glass. Due to the high specific surface of andesitic ash particles are capable of retaining an electrostatic charge and absorb droplets of water and corrosive acids. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines. To reduce the risk of collision of aircraft with ash clouds of Kamchatkan volcanoes, was

  9. Volcanic ash-leachates: a review and recommendations for sampling methods

    NASA Astrophysics Data System (ADS)

    Witham, C. S.; Oppenheimer, C.; Horwell, C. J.

    2005-03-01

    Tephra in plumes can scavenge and thereby rapidly deposit volatiles including sulphur, halogen and metal species. These may then be leached (e.g. by rainfall), potentially releasing heavy loadings to soils and water bodies. Several eruptions have resulted in contamination of pasture, sometimes with serious impacts on livestock. Water quality has also been an issue in some areas affected by tephra fall. This work synthesises the literature on volcanic ash-leachates and considers the controls on volatile adsorption. General trends emerge for basaltic, intermediate and silicic tephra, as well as for variable particle size and transport distance. The applications of ash-leachate data to plume-gas geochemistry, calculation of volatile budgets and environmental impact assessment are evaluated. Comparisons for different eruptions are hampered by disparities in leachate analysis techniques. A standardised methodology is therefore proposed to facilitate future health impact assessment and volcanological interpretation of results from different sites.

  10. Aviation response to a widely dispersed volcanic ash and gas cloud from the August 2008 eruption of Kasatochi, Alaska, USA

    USGS Publications Warehouse

    Guffanti, Marianne; Schneider, David J.; Wallace, Kristi L.; Hall, Tony; Bensimon, Dov R.; Salinas, Leonard J.

    2010-01-01

    The extensive volcanic cloud from Kasatochi's 2008 eruption caused widespread disruptions to aviation operations along Pacific oceanic, Canadian, and U.S. air routes. Based on aviation hazard warnings issued by the National Oceanic and Atmospheric Administration, U.S. Geological Survey, the Federal Aviation Administration, and Meteorological Service of Canada, air carriers largely avoided the volcanic cloud over a 5 day period by route modifications and flight cancellations. Comparison of time coincident GOES thermal infrared (TIR) data for ash detection with Ozone Monitoring Instrument (OMI) ultraviolet data for SO2 detection shows congruent areas of ash and gas in the volcanic cloud in the 2 days following onset of ash production. After about 2.5 days, the area of SO2 detected by OMI was more extensive than the area of ash indicated by TIR data, indicating significant ash depletion by fall out had occurred. Pilot reports of visible haze at cruise altitudes over Canada and the northern United States suggested that SO2 gas had converted to sulfate aerosols. Uncertain about the hazard potential of the aging cloud, airlines coped by flying over, under, or around the observed haze layer. Samples from a nondamaging aircraft encounter with Kasatochi's nearly 3 day old cloud contained volcanic silicate particles, confirming that some fine ash is present in predominantly gas clouds. The aircraft's exposure to ash was insufficient to cause engine damage; however, slightly damaging encounters with volcanic clouds from eruptions of Reventador in 2002 and Hekla in 2000 indicate the possibility of lingering hazards associated with old and/or diffuse volcanic clouds.

  11. Use of magnetic hysteresis properties and electron spin resonance spectroscopy for the identification of volcanic ash: a preliminary study

    NASA Astrophysics Data System (ADS)

    Pawse, Archana; Beske-Diehl, Suzanne; Marshall, S. A.

    1998-03-01

    This initial study investigates the possible use of hysteresis parameters and electron spin resonance (ESR) spectroscopy to identify and correlate volcanic ash. ESR and hysteresis properties are sensitive to characteristics such as the chemical composition, mineralogy, and grain size and shape. These characteristics are determined by the tectonic setting of the volcano and by the magmatic and eruptive history of the volcanic ash. Hysteresis properties and ESR spectra, therefore, should be distinct for each ash eruption and may help to identify the eruptive source of the ash and to correlate ash from unknown sources. We conducted ESR spectroscopy at room temperature and magnetic hysteresis measurements on 19 samples of a single ash, the 1974 October 14 eruption of the Fuego volcano, Guatemala, and on single samples of ash obtained from eight different volcanoes. The Fuego ash samples were obtained at increasing distances from the volcano. For the single Fuego ash, ESR spectra and hysteresis parameters become increasingly similar as the distance from the volcano increases. At distances greater than 30km, ESR spectra and hysteresis properties are uniform. The variability of magnetic and ESR properties with distance from Fuego is due to the preferential fall-out of phenocrysts closer to the volcano. At large distances, the ash is more uniform, containing more glass and microcrystals. All eight ash samples from the different volcanoes can be distinguished from the distal Fuego 1974 October 14 ash using ESR spectra and hysteresis parameters. These results suggest that ESR and hysteresis measurements have a potential to be used as tools to identify distal ash when used in conjunction with geochemical, mineralogical and/or other types of data.

  12. Compton-Belkovich Volcanic Complex (CBVC): An ash flow caldera on the Moon

    NASA Astrophysics Data System (ADS)

    Chauhan, M.; Bhattacharya, S.; Saran, S.; Chauhan, P.; Dagar, A.

    2015-06-01

    Volcanic calderas are found on Earth, Mars, Venus and Io, and are rare, but unique volcanic structures in the Solar System. Compton-Belkovich Volcanic Complex (CBVC) (60.5°N-99.5°E) on the far side of the Moon is a unique non-mare feature due to its evolved lithology, regional tectonic setting, its location being near the north pole, far from the Procellarum KREEP Terrane (PKT) and its recent association with endogenic water. High-resolution remote sensing observations of several structural features at CBVC such as ring faults, radial faults, fractures manifested by various morphological features such as domes of varied sizes and shapes and pyroclastic ash flows characterize it to be a volcanic caldera. The loading of Humboldtianum basin with basalts and subsequent development of extensional structures outside it along with high-thorium anomaly and resulting silicic volcanism at CBVC producing central collapsed caldera could be considered as an analogy to silicic calderas on Earth formed in extensional tectonic regime even though the tectonic processes involved in these two cases are entirely different, the former being impact-related, whereas the latter involves rifting or hotspot-related activities associated with extensional plate tectonics. Presence of high-reflectance feature and its extension to the east-southeast of the topographic expression and its relation with pyroclastic dispersal have been supported by radar-based Mini-RF observations and high-resolution LROC-NAC imagery. It suggests the presence of a late-stage fine pyroclastic layer within the CBVC region. The diverse volcanic features that exist at the studied site indicate a series of deformation and eruption events associated with silicic magmatism and thus, CBVC could be considered as an ash flow caldera on the Moon. Here, we present a detailed appraisal of various volcanic and structural features detected at CBVC through high-resolution optical as well as radar observations. Based on the

  13. Environmental hazards of fluoride in volcanic ash: a case study from Ruapehu volcano, New Zealand

    NASA Astrophysics Data System (ADS)

    Cronin, Shane J.; Neall, V. E.; Lecointre, J. A.; Hedley, M. J.; Loganathan, P.

    2003-03-01

    The vent-hosted hydrothermal system of Ruapehu volcano is normally covered by a c. 10 million m 3 acidic crater lake where volcanic gases accumulate. Through analysis of eruption observations, granulometry, mineralogy and chemistry of volcanic ash from the 1995-1996 Ruapehu eruptions we report on the varying influences on environmental hazards associated with the deposits. All measured parameters are more dependent on the eruptive style than on distance from the vent. Early phreatic and phreatomagmatic eruption phases from crater lakes similar to that on Ruapehu are likely to contain the greatest concentrations of environmentally significant elements, especially sulphur and fluoride. These elements are contained within altered xenolithic material extracted from the hydrothermal system by steam explosions, as well as in residue hydrothermal fluids adsorbed on to particle surfaces. In particular, total F in the ash may be enriched by a factor of 6 relative to original magmatic contents, although immediately soluble F does not show such dramatic increases. Highly soluble NaF and CaSiF 6 phases, demonstrated to be the carriers of 'available' F in purely magmatic eruptive systems, are probably not dominant in the products of phreatomagmatic eruptions through hydrothermal systems. Instead, slowly soluble compounds such as CaF 2, AlF 3 and Ca 5(PO 4) 3F dominate. Fluoride in these phases is released over longer periods, where only one third is leached in a single 24-h water extraction. This implies that estimation of soluble F in such ashes based on a single leach leads to underestimation of the F impact, especially of a potential longer-term environmental hazard. In addition, a large proportion of the total F in the ash is apparently soluble in the digestive system of grazing animals. In the Ruapehu case this led to several thousand sheep deaths from fluorosis.

  14. HCl uptake by volcanic ash in the high temperature eruption plume: mechanistic insights

    NASA Astrophysics Data System (ADS)

    Ayris, P. M.; Delmelle, P.; Cimarelli, C.; Maters, E. C.; Suzuki, Y.; Dingwell, D. B.

    2014-12-01

    The injection of HCl into the stratosphere by large volcanic eruptions is considered to be little importance, due to the efficient incorporation of the former into hydrometeors within the cooling plume. However, HCl is also adsorbed onto ash surfaces to form soluble -Cl salts within the high temperature core of the eruption plume, and the atmospheric and environmental significance of this process is uncertain. We investigate the capacity of volcanic glasses with tephrite, phonolite, dacite, and rhyolite compositions to adsorb HCl at temperatures of 200-800°C in the presence of SO2, CO2 and He. Experiments show that only tephrite and phonolite glasses are significantly reactive to HCl, exhibiting optimal uptake at 400-600°C. The primary reaction product formed during adsorption is NaCl, but Ca-, K-, Al- and Fe- chlorides are also identified. Uptake of HCl by glass surfaces is sustained by interdiffusion of Na+ and other Cl-reactive cations with H+. Diffusion coefficient calculations yield Na diffusion coefficients for the four glasses, suggesting that the structural role for Na within the glass network governs the capacity for HCl retention. The uptake of HCl under experimental conditions is limited above 500°C by a Cl-induced dehydroxylation process, but the presence of H2O in the hydrous eruption plume may sustain or enhance adsorption. The experimental data, combined with simulated plume cooling profiles, suggest that HCl adsorption can be a significant scavenging mechanism in large explosive eruptions, particularly in peralkaline systems. The fate of adsorbed HCl is variable; some may be retained on ash surfaces within pyroclastic flows, while chloride-coated ash in the stratosphere could promote the formation of reactive Cl species associated with O3 destruction. Additionally, Fe- and Cl-bearing salts emplaced on ash surfaces by HCl adsorption within the plume cores of large explosive eruptions may increase the ocean fertilising potential of such events.

  15. Possible role of volcanic ash-gas clouds in the Earth's prebiotic chemistry.

    PubMed

    Basiuk, V A; Navarro-Gonzalez, R

    1996-04-01

    Volcanic ash-gas clouds represent versatile local atmospheric environments appropriate for abiotic synthesis of rather complex organic molecules due to the simultaneous presence of various gaseous reagents, catalytically active inorganic particles, electric discharges, pressure and temperature gradients. They are relatively readily attainable for the scientists, contrary to objects or events of space origin (interstellar and planetary dust, meteoritic/cometary impacts, etc.), providing excellent opportunities for in situ studies and grounded simulating experiments. This paper reviews the available data on this environment, its most important chemical and physical parameters. Based on this analysis, it is suggested in brief experimental conditions for the simulation.

  16. Possible role of volcanic ash-gas clouds in the Earth's prebiotic chemistry.

    PubMed

    Basiuk, V A; Navarro-Gonzalez, R

    1996-04-01

    Volcanic ash-gas clouds represent versatile local atmospheric environments appropriate for abiotic synthesis of rather complex organic molecules due to the simultaneous presence of various gaseous reagents, catalytically active inorganic particles, electric discharges, pressure and temperature gradients. They are relatively readily attainable for the scientists, contrary to objects or events of space origin (interstellar and planetary dust, meteoritic/cometary impacts, etc.), providing excellent opportunities for in situ studies and grounded simulating experiments. This paper reviews the available data on this environment, its most important chemical and physical parameters. Based on this analysis, it is suggested in brief experimental conditions for the simulation. PMID:11536751

  17. Evidence of Carboniferous volcanic ash in Pictou Group (West-phalian D), Sydney Coalfield, Nova Scotia, Canada

    SciTech Connect

    Lyons, P.C.; Outerbridge, W.F. ); Hacquebard, P.A. )

    1991-08-01

    Until now, Carboniferous-altered volcanic ash in North America was known only from the Middle Pennsylvanian (upper Westphalian A to lower Westphalian D) of the Appalachian basin. Now, however, mineralogical analysis of thin claystones (8-24 mm thick) in mineable bituminous coal (Hub and Harbour seams) form the P-boreholes in the Donkin submarine areas of the Sydney coalfield, Nova Scotia, indicates the presence of trace amounts of minerals probably derived from a volcanic ash fall of late Westphalian D age. Water-clear to cloudy quartz splinters and euhedral zircon with sharp crystal faces and edges, and length-to-width ratios up to 6:1 - which are typical of Appalachian altered acidic volcanic ash deposits (tonsteins) - were with a dominantly detrital (fluvial ) mineral suite. Fifty to 90% water-laid silt- to sand-size detrital grains of quartz, tourmaline( ), zircon, white mica, and other minerals are found in the HF residum after the removal of the dominant components: clay minerals, pyrite, and coal particles (spores, secretinite, etc.). The fine size of the volcanic minerals and their low concentration indicate a very distant volcanic ash source, perhaps western Europe, where volcanic activity extended into the Stephanian.

  18. Understanding volcanism at the PETM: Abundant volcanic ash layers in the Central Tertiary Basin of Spitsbergen, Svalbard

    NASA Astrophysics Data System (ADS)

    Jones, Morgan; Eliassen, Gauti; Svensen, Henrik; Jochmann, Malte; Friis, Bjarki; Jerram, Dougal; Planke, Sverre

    2014-05-01

    During the early Tertiary, Svalbard developed a fold-thrust belt on its western margin with an associated foreland basin in the central-south of what is now Spitsbergen. This Central Tertiary Basin (CTB) is a syn-orogenic sedimentary basin in a strike-slip regime. The CTB contains the ~1900 m thick Van Mijenfjorden group, a dominantly sandstone-shale succession that was deposited in a North-South extending basin. Sediments in this group display evidence of major transgressive-regressive cycles related to local tectonics and eustatic sea level change. This basin is ideal for study as it has been extensively cored for coal prospecting, allowing a suite of sedimentary logs across the basin to be considered. Prominent marker beds in this sedimentary sequence are 1-30 cm thick bentonites, formed from the chemical weathering of volcanic tuff deposits. In this study, we focus on 8 sedimentary logs across the CTB, spanning the Palaeocene to lower Eocene in age. Bentonites are common in the Palaeocene cores (Basilika and Grumantbyen formations), while rarer but still occasionally present in the Eocene Frysjaodden formation. The cores had between 3-12 observable bentonite layers that showed large variations in preservation and subsequent reworking. Roots and other finer organic material were common, especially when the bentonites were found next to coal seams. Geochemical affinities between ash layers were investigated to identify basin-wide depositional events, with the aim of elucidating the provenance of these ashes. This sedimentary sequence is of broader interest as it covers the Palaeocene-Eocene thermal maximum (PETM), an extreme global warming event driven by large releases to the atmosphere of CO2 and/or CH4, evidenced by a negative carbon isotope excursion in both the ocean and atmosphere. Potential sources include volcanism and associated gas release from intruded sediments, CH4 hydrate dissociation, and/or the oxidation of organic matter. These formations are

  19. Consequences of volcanic ash deposition on the locomotor performance of the Phymaturus spectabilis lizard from Patagonia, Argentina.

    PubMed

    Cabezas-Cartes, Facundo; Kubisch, Erika Leticia; Ibargüengoytía, Nora Ruth

    2014-03-01

    The locomotor performance of lizards depends on their morphological and physiological adaptations to the habitat. However, when the habitat changes dramatically, for example, by a volcanic eruption, the performance of lizards may be affected. We registered the vegetation cover, the surface covered by ash, the presence of crevices suitable for Phymaturus and the rocks slopes to analyze the effects of ash accumulation produced by the eruption of Puyehue-Cordon Caulle volcanic complex on microhabitat use and availability of the Phymaturus spectabilis lizard. In addition, we studied the effect of ashes and slope on the locomotor performance of P. spectabilis by registering the maximum speed in sprint runs and long runs under four different treatments (cork and on the level, ashes and on the level, cork and slope, and ashes and slope). P. spectabilis selected microhabitats unvegetated, with crevices and steep slopes. Regarding locomotor performance, the speed of lizards was negatively affected by the presence of ash only in sprint runs on the level and in long runs with slope. The slope had a negative impact on the speed in all the treatments. These results show that the presence of volcanic ashes in the substrate might have affected the locomotor performance of the lizards, especially in long runs, and hence, the interaction of individuals with the environment, that is, escaping from predators and social behavior.

  20. Consequences of volcanic ash deposition on the locomotor performance of the Phymaturus spectabilis lizard from Patagonia, Argentina.

    PubMed

    Cabezas-Cartes, Facundo; Kubisch, Erika Leticia; Ibargüengoytía, Nora Ruth

    2014-03-01

    The locomotor performance of lizards depends on their morphological and physiological adaptations to the habitat. However, when the habitat changes dramatically, for example, by a volcanic eruption, the performance of lizards may be affected. We registered the vegetation cover, the surface covered by ash, the presence of crevices suitable for Phymaturus and the rocks slopes to analyze the effects of ash accumulation produced by the eruption of Puyehue-Cordon Caulle volcanic complex on microhabitat use and availability of the Phymaturus spectabilis lizard. In addition, we studied the effect of ashes and slope on the locomotor performance of P. spectabilis by registering the maximum speed in sprint runs and long runs under four different treatments (cork and on the level, ashes and on the level, cork and slope, and ashes and slope). P. spectabilis selected microhabitats unvegetated, with crevices and steep slopes. Regarding locomotor performance, the speed of lizards was negatively affected by the presence of ash only in sprint runs on the level and in long runs with slope. The slope had a negative impact on the speed in all the treatments. These results show that the presence of volcanic ashes in the substrate might have affected the locomotor performance of the lizards, especially in long runs, and hence, the interaction of individuals with the environment, that is, escaping from predators and social behavior. PMID:24273207

  1. Volcanic particle aggregation in explosive eruption columns. Part I: Parameterization of the microphysics of hydrometeors and ash

    NASA Astrophysics Data System (ADS)

    Textor, C.; Graf, H. F.; Herzog, M.; Oberhuber, J. M.; Rose, William I.; Ernst, G. G. J.

    2006-02-01

    The aggregation of volcanic ash particles within the eruption column of explosive eruptions has been observed at many volcanoes. It influences the residence time of ash in the atmosphere and the radiative properties of the umbrella cloud. However, the information on the processes leading to aggregate formation are still either lacking or very incomplete. We examine the fate of ash particles through numerical experiments with the plume model ATHAM (Active Tracer High resolution Atmospheric Model) in order to determine the conditions that promote ash particle aggregation. In this paper we describe the microphysics and parameterization of ash and hydrometeors. In a companion paper (this issue) we use this information in a series of numerical experiments. The parameterization includes the condensation of water vapor in the rising eruption column. The formation of liquid and solid hydrometeors and the effect of latent heat release on the eruption column dynamics are considered. The interactions of hydrometeors and volcanic ash within the eruption column that lead to aggregate formation are simulated for the first time within a rising eruption column. The microphysical parameterization follows a modal approach. The hydrometeors are described by two size classes, each of which is divided into a liquid and a frozen category. By analogy with the hydrometeor classification, we specify four categories of volcanic ash particles. We imply that volcanic particles are active as condensation nuclei for water and ice formation. Ash can be contained in all categories of hydrometeors, thus forming mixed particles of any composition reaching from mud rain to accretionary lapilli. Collisions are caused by gravitational capture of particles with different fall velocity. Coalescence of hydrometeor-ash aggregates is assumed to be a function of the hydrometeor mass fraction within the mixed particles. The parameterization also includes simplified descriptions of electrostatics and salinity

  2. A new method for GPS-based wind speed determinations during airborne volcanic plume measurements

    USGS Publications Warehouse

    Doukas, Michael P.

    2002-01-01

    Begun nearly thirty years ago, the measurement of gases in volcanic plumes is today an accepted technique in volcano research. Volcanic plume measurements, whether baseline gas emissions from quiescent volcanoes or more substantial emissions from volcanoes undergoing unrest, provide important information on the amount of gaseous output of a volcano to the atmosphere. Measuring changes in gas emission rates also allows insight into eruptive behavior. Some of the earliest volcanic plume measurements of sulfur dioxide were made using a correlation spectrometer (COSPEC). The COSPEC, developed originally for industrial pollution studies, is an upward-looking optical spectrometer tuned to the ultraviolet absorption wavelength of sulfur dioxide (Millán and Hoff, 1978). In airborne mode, the COSPEC is mounted in a fixed-wing aircraft and flown back and forth just underneath a volcanic plume, perpendicular to the direction of plume travel (Casadevall and others, 1981; Stoiber and others, 1983). Similarly, for plumes close to the ground, the COSPEC can be mounted in an automobile and driven underneath a plume if a suitable road system is available (Elias and others, 1998). The COSPEC can also be mounted on a tripod and used to scan a volcanic plume from a fixed location on the ground, although the effectiveness of this configuration declines with distance from the plume (Kyle and others, 1990). In the 1990’s, newer airborne techniques involving direct sampling of volcanic plumes with infrared spectrometers and electrochemical sensors were developed in order to measure additional gases such as CO2 and H2S (Gerlach and others, 1997; Gerlach and others, 1999; McGee and others, 2001). These methods involve constructing a plume cross-section from several measurement traverses through the plume in a vertical plane. Newer instruments such as open-path Fourier transform infrared (FTIR) spectrometers are now being used to measure the gases in volcanic plumes mostly from fixed

  3. Correlation and Analysis of Volcanic Ash in Marine Sediments From the Peru Margin: Explosive Volcanic Cycles of the North-Central Andes

    NASA Astrophysics Data System (ADS)

    Hart, D.; Miller, J.

    2003-12-01

    To decipher the episodicity of explosive volcanic activity in the North-Central Andes, we have measured the thickness and calculated the volume of ash layers from sites drilled along the Peru margin during Leg 201 of the Ocean Drilling Program (ODP). The geographic distribution of the sites (over 3 degrees of latitude and from 50 to 300 km offshore) and correlation of ash units between sites form the basis for minimal estimates of explosive volcanic activity in the region (only eruptions large enough to deposit ash in excess of 100 km from source are represented). Pouclet et al., (1990), estimated the minimum explosive activity along the Andean Arc from ash-bearing sediments and ash layers within cores from sites along the Peru margin collected during ODP Leg 112. As a result of higher recovery (as much as ten times more core recovery in many intervals) and decreased disturbance in cores recovered during Leg 201, our documentation of ash content in cores from Leg 201 has led to a more complete record of the explosive volcanic activity along the Andean Arc. For example, Pouclet, et al., (1990), reports four ash layers from Sites 680 and 684, whereas we have documented fourteen ash layers from cores recovered from the same locations (Sites 1228 and 1227, respectively). Our stratigraphic record agrees with Pouclet, et al., (1990), suggesting that explosive activity began in the early Eocene ( ˜35Ma) and continued with explosive pulses during the Miocene. The greatest explosive activity occurred within the past 5 million years, with peak activity in the late Pliocene to early Pleistocene. Based on petrographic and geochemical analysis, most of the volcanic ash within cores from Leg 201 was derived from the Andean volcanic arc. These plinian eruptions produced acidic glasses and ash layers with abundant feldspar, hornblende, and biotite. Pouclet, et al., (1990), reports a transition from andesitic volcanism in the Middle to Late Miocene to a more shoshonitic

  4. Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

    PubMed

    Karbowska, Bozena; Zembrzuski, Wlodzimierz

    2016-07-01

    Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase. PMID:27209545

  5. Fractionation and Mobility of Thallium in Volcanic Ashes after Eruption of Eyjafjallajökull (2010) in Iceland.

    PubMed

    Karbowska, Bozena; Zembrzuski, Wlodzimierz

    2016-07-01

    Volcanic ash contains thallium (Tl), which is highly toxic to the biosphere. The aim of this study was to determine the Tl concentration in fractions of volcanic ash samples originating from the Eyjafjallajökull volcano. A sequential extraction scheme allowed for a study of element migration in the environment. Differential pulse anodic stripping voltammetry using a flow measuring system was selected as the analytical method to determine Tl content. The highest average content of Tl in volcanic ash was determined in the fraction entrapped in the aluminosilicate matrix (0.329 µg g(-1)), followed by the oxidizable fraction (0.173 µg g(-1)). The lowest content of Tl was found in the water soluble fraction (0.001 µg g(-1)); however, this fraction is important due to the fact that Tl redistribution among all the fractions occurs through the aqueous phase.

  6. Encounters of aircraft with volcanic ash clouds; A compilation of known incidents, 1953-2009

    USGS Publications Warehouse

    Guffanti, Marianne; Casadevall, Thomas J.; Budding, Karin

    2010-01-01

    Information about reported encounters of aircraft with volcanic ash clouds from 1953 through 2009 has been compiled to document the nature and scope of risks to aviation from volcanic activity. The information, gleaned from a variety of published and other sources, is presented in database and spreadsheet formats; the compilation will be updated as additional encounters occur and as new data and corrections come to light. The effects observed by flight crews and extent of aircraft damage vary greatly among incidents, and each incident in the compilation is rated according to a severity index. Of the 129 reported incidents, 94 incidents are confirmed ash encounters, with 79 of those having various degrees of airframe or engine damage; 20 are low-severity events that involve suspected ash or gas clouds; and 15 have data that are insufficient to assess severity. Twenty-six of the damaging encounters involved significant to very severe damage to engines and (or) airframes, including nine encounters with engine shutdown during flight. The average annual rate of damaging encounters since 1976, when reporting picked up, has been approximately 2 per year. Most of the damaging encounters occurred within 24 hours of the onset of ash production or at distances less than 1,000 kilometers from the source volcanoes. The compilation covers only events of relatively short duration for which aircraft were checked for damage soon thereafter; documenting instances of long-term repeated exposure to ash (or sulfate aerosols) will require further investigation. Of 38 source volcanoes, 8 have caused 5 or more encounters, of which the majority were damaging: Augustine (United States), Chaiten (Chile), Mount St. Helens (United States), Pacaya (Guatemala), Pinatubo (Philippines), Redoubt (United States), Sakura-jima (Japan), and Soufriere Hills (Montserrat, Lesser Antilles, United Kingdom). Aircraft have been damaged by eruptions ranging from small, recurring episodes to very large

  7. Ground-based microwave radar and optical lidar signatures of volcanic ash plumes: models, observations and retrievals

    NASA Astrophysics Data System (ADS)

    Mereu, Luigi; Marzano, Frank; Mori, Saverio; Montopoli, Mario; Cimini, Domenico; Martucci, Giovanni

    2013-04-01

    The detection and quantitative retrieval of volcanic ash clouds is of significant interest due to its environmental, climatic and socio-economic effects. Real-time monitoring of such phenomena is crucial, also for the initialization of dispersion models. Satellite visible-infrared radiometric observations from geostationary platforms are usually exploited for long-range trajectory tracking and for measuring low level eruptions. Their imagery is available every 15-30 minutes and suffers from a relatively poor spatial resolution. Moreover, the field-of-view of geostationary radiometric measurements may be blocked by water and ice clouds at higher levels and their overall utility is reduced at night. Ground-based microwave radars may represent an important tool to detect and, to a certain extent, mitigate the hazard from the ash clouds. Ground-based weather radar systems can provide data for determining the ash volume, total mass and height of eruption clouds. Methodological studies have recently investigated the possibility of using ground-based single-polarization and dual-polarization radar system for the remote sensing of volcanic ash cloud. A microphysical characterization of volcanic ash was carried out in terms of dielectric properties, size distribution and terminal fall speed, assuming spherically-shaped particles. A prototype of volcanic ash radar retrieval (VARR) algorithm for single-polarization systems was proposed and applied to S-band and C-band weather radar data. The sensitivity of the ground-based radar measurements decreases as the ash cloud is farther so that for distances greater than about 50 kilometers fine ash might be not detected anymore by microwave radars. In this respect, radar observations can be complementary to satellite, lidar and aircraft observations. Active remote sensing retrieval from ground, in terms of detection, estimation and sensitivity, of volcanic ash plumes is not only dependent on the sensor specifications, but also on

  8. Proof-of-principle results for identifying the composition of dust particles and volcanic ash samples through the technique of photon activation analysis at the IAC

    NASA Astrophysics Data System (ADS)

    Mamtimin, Mayir; Cole, Philip L.; Segebade, Christian

    2013-04-01

    Instrumental analytical methods are preferable in studying sub-milligram quantities of airborne particulates collected in dust filters. The multi-step analytical procedure used in treating samples through chemical separation can be quite complicated. Further, due to the minute masses of the airborne particulates collected on filters, such chemical treatment can easily lead to significant levels of contamination. Radio-analytical techniques, and in particular, activation analysis methods offer a far cleaner alternative. Activation methods require minimal sample preparation and provide sufficient sensitivity for detecting the vast majority of the elements throughout the periodic table. In this paper, we will give a general overview of the technique of photon activation analysis. We will show that by activating dust particles with 10- to 30-MeV bremsstrahlung photons, we can ascertain their elemental composition. The samples are embedded in dust-collection filters and are irradiated "as is" by these photons. The radioactivity of the photonuclear reaction products is measured with appropriate spectrometers and the respective analytes are quantified using multi-component calibration materials. We shall provide specific examples of identifying the elemental components of airborne dust particles and volcanic ash by making use of bremsstrahlung photons from an electron linear accelerator at the Idaho Accelerator Center in Pocatello, Idaho.

  9. The European air traffic management response to volcanic ash crises: towards institutionalised aviation crisis management.

    PubMed

    Dopagne, Jacques

    2011-06-01

    A cloud of ash drifting from the erupting Eyjafjallajökull volcano in Iceland in April and May 2010 covered Europe and created an unprecedented situation. It resulted in an almost complete lockdown of European airspace in the period from 15th to 21st April, 2010: more than 100,000 flights were cancelled, 10 million people were affected and over US$1.8bn was lost by airlines globally. This paper presents the air traffic management (ATM) view of the situation. Through an analysis of the evolution of the events in the affected region, the paper will provide more details on ATM planning, reaction and follow-up actions. Furthermore, the influence of this event on the identification of further improvements needed to advance volcanic procedures internationally will be discussed. Actions undertaken since the end of the event - the establishment of the European Aviation Crisis Coordination Cell, running of the International Civil Aviation Organization VOLCEX 11/01 volcanic ash exercise and European response to the Grimsvötn eruption in May 2011 - will be discussed at the end of the paper. PMID:21835749

  10. Aerosols Monitoring Network to Create a Volcanic ASH Risk Management System in Argentina and Chile

    NASA Astrophysics Data System (ADS)

    Quel, Eduardo; Sugimoto, Nobuo; Otero, Lidia; Jin, Yoshitaka; Ristori, Pablo; Nishizawa, Tomoaki; González, Francisco; Papandrea, Sebastián; Shimizu, Atsushi; Mizuno, Akira

    2016-06-01

    Two main decisions were made in Argentina to mitigate the impact of the recent volcanic activity in de country basically affected by the presence of volcanic ash in the air and deposited over the Argentinean territory. The first one was to create a risk management commission were this risk between others were studied, and second to develop new ground based remote sensing technologies to be able to identify and inform the risk close to the airports. In addition the Japanese government program for Science and Technology joint Research Partnership between Argentina, Chile and Japan for Sustainable Development (SATREPS) accepted to fund this cooperation due to the potential future utilization of the research outcomes to the benefit of the society. This work present the actual achievements and expected advance of these projects that try to joint efforts between national and international agencies as well as countries on behalf of a better understanding of the risks and a joint collaboration on the mitigation of suspended ashes impact over the aerial navigation.

  11. The European air traffic management response to volcanic ash crises: towards institutionalised aviation crisis management.

    PubMed

    Dopagne, Jacques

    2011-06-01

    A cloud of ash drifting from the erupting Eyjafjallajökull volcano in Iceland in April and May 2010 covered Europe and created an unprecedented situation. It resulted in an almost complete lockdown of European airspace in the period from 15th to 21st April, 2010: more than 100,000 flights were cancelled, 10 million people were affected and over US$1.8bn was lost by airlines globally. This paper presents the air traffic management (ATM) view of the situation. Through an analysis of the evolution of the events in the affected region, the paper will provide more details on ATM planning, reaction and follow-up actions. Furthermore, the influence of this event on the identification of further improvements needed to advance volcanic procedures internationally will be discussed. Actions undertaken since the end of the event - the establishment of the European Aviation Crisis Coordination Cell, running of the International Civil Aviation Organization VOLCEX 11/01 volcanic ash exercise and European response to the Grimsvötn eruption in May 2011 - will be discussed at the end of the paper.

  12. Volcanic ash layers in blue ice fields (Beardmore Glacier Area, Antarctica): Iridium enrichments

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian

    1988-01-01

    Dust bands on blue ice fields in Antarctica have been studied and have been identified to originate from two main sources: bedrock debris scraped up from the ground by the glacial movement (these bands are found predominantly at fractures and shear zones in the ice near moraines), and volcanic debris deposited on and incorporated in the ice by large-scale eruptions of Antarctic (or sub-Antractic) volcanoes. Ice core studies have revealed that most of the dust layers in the ice cores are volcanic (tephra) deposits which may be related to some specific volcanic eruptions. These eruptions have to be related to some specific volcanic eruptions. These eruptions have to be relatively recent (a few thousand years old) since ice cores usually incorporate younger ice. In contrast, dust bands on bare blue ice fields are much older, up to a few hundred thousand years, which may be inferred from the rather high terrestrial age of meteorites found on the ice and from dating the ice using the uranium series method. Also for the volcanic ash layers found on blue ice fields correlations between some specific volcanoes (late Cenozoic) and the volcanic debris have been inferred, mainly using chemical arguments. During a recent field expedition samples of several dust bands found on blue ice fields at the Lewis Cliff Ice Tongue were taken. These dust band samples were divided for age determination using the uranium series method, and chemical investigations to determine the source and origin of the dust bands. The investigations have shown that most of the dust bands found at the Ice Tongue are of volcanic origin and, for chemical and petrological reasons, may be correlated with Cenozoic volcanoes in the Melbourne volcanic province, Northern Victoria Land, which is at least 1500 km away. Major and trace element data have been obtained and have been used for identification and correlation purposes. Recently, some additional trace elements were determined in some of the dust band

  13. Multi-parametric observation of volcanic lightning produced by ash-rich plumes at Sakurajima volcano, Japan.

    NASA Astrophysics Data System (ADS)

    Cimarelli, Corrado; Alatorre-Ibargüengoitia, Miguel; Aizawa, Koki; Scheu, Bettina; Yokoo, Akihiko; Mueller, Sebastian; Dingwell, Donald B.

    2014-05-01

    Ash-rich volcanic plumes are very often associated with electrical discharges producing a majestic display of volcanic lightning. While the direct threat posed by volcanic lightning is small in comparison to other hazards, observation and understanding of this phenomenon can shed light on important properties of the plume such as mass eruption rate and content of fine particles as recently demonstrated by laboratory investigation of volcanic lightning (Cimarelli et al., 2014). Electrical charging of ash particles within the plume can in addition play an important role in aggregation processes therefore influencing the dispersion and sedimentation of tephra. Despite the recent advances in the experimental investigations under controlled conditions and the increasing detailed observation by lightning monitoring arrays, many fundamental questions about electrical discharges in volcanic plume still remain unsolved. In particular, to which extent electrical discharges in volcanic plumes are comparable to thundercloud lightning? Is the presence of hydrometeors in the plume a necessary condition for the generation of volcanic lightning? Answering these questions is vital for the thorough understanding of the electrification process and in turn it is fundamental to fully decipher what volcanic lightning can tell us about the properties of volcanic plumes. The combination of multiparametric observation of electrical activity at erupting volcanoes can undoubtedly help us answering these questions. Here we present preliminary results from a campaign of measurements conducted at Sakurajima volcano in Japan where we combined high-speed imaging with magnetotelluric and acoustic measurements of ash-rich plumes generating electrical discharges and compare our observation with maximum plume height measurement and atmospheric soundings. We invite discussions on cross-correlation of relevant monitoring techniques and possible future developments of multi-parametric arrays. Cimarelli

  14. Integration between Satellite and Ground-Based Data for the Improvement of Volcanic Ash Retrievals and Eruption Characterization

    NASA Astrophysics Data System (ADS)

    Corradini, S.; Merucci, L.; Marzano, F. S.; Montopoli, M.; Vulpiani, G.; Ricci, M.; Guerrieri, L.; Pugnaghi, S.; Scollo, S.; Coltelli, M.; Stramondo, S.

    2014-12-01

    Due to the large emission of gas and ash particles into the atmosphere, volcanic eruptions are among the most important sources of natural pollution. The size, density and shape of volcanic ash particles determine their residence time in the atmosphere that varies from minutes (for particles with radius larger than 100 μm) to weeks (for particles smaller than 10 μm). The interest in determining the abundances of these particles is high because of their effects on the environment, climate, public health and aviation. A practical consequence after the recent 2010 Eyjafjallajökull (Iceland) eruption, was the introduction of a volcanic ash concentration threshold to reduce the level of flight disruption whilst ensuring the passenger safety. This requirement forces the scientific community to develop novel techniques to obtain reliable results in real time. On the other hand, from the research point of view, an accurate estimation of the volcanic ash emissions can also yield insights into magmatic processes which control volcanic activity during the eruptive phases.Worldwide volcanic activity is observed with a variety of ground and space-based instruments that offer advantages and drawbacks. Because doesn't exist a single system able to give a comprehensive description of a particular phenomenon, an integrated approach based on the use of different types of remote sensing data is required. This approach is the core of the Multi-platform volcanic Ash Cloud Estimation (MACE) procedure that will be developed within the European FP7-APHORISM project.In this is work the measurements obtained from the geostationary MSG-SEVIRI, the polar Terra/Aqua MODIS and the ground-based weather RADAR instruments are integrated thus blending infrared and microwave ash estimation techniques from space and ground platforms. The expected outcomes are the improvements of the volcanic ash retrievals (mass, aerosol optical depth, effective radius, concentration, size distribution, cloud

  15. Resonances of a Volcanic Conduit Triggered by Repetitive Injections of an Ash-laden gas

    NASA Astrophysics Data System (ADS)

    Molina, I.; Kumagai, H.; Yepes, H.

    2003-12-01

    Tungurahua Volcano, located at the center of the Ecuadorian Andes, entered in eruption characterized by ash emissions, vulcanian and strombolian activities in October 1999. There have been 7 to 10 short-period seismic stations and 1 broadband station to monitor the Tungurahua volcanic activity. Between December 5 and 11, 2001, a swarm of long-period (LP) events occurred. The LP waveform is characterized by screw-shaped harmonic oscillations. In this study, we used the LP waveforms to calculate temporal variations in their complex frequencies (frequency, f and quality factor, Q) to understand the source process associated with this activity. We applied the Sompi spectral method to 57 LP waveforms from the station RETU, which provided the best continuous data in the Tungurahua seismic network. We determined the temporal variations in the complex frequencies of the LP events, which indicated that the frequency gradually decreased from 3.5 to 2 Hz, whereas Q gradually increased from 100 to 400 with wide scatter along this trend. Based on the acoustic properties of a crack containing various types of magmatic and hydrothermal fluids, the observed high Q values can only be explained by a large velocity contrast between the surrounding rock and fluid. Such a high velocity contrast suggests ash-gas or water droplet-gas mixtures in a crack developed in the solid rock. Since the LP events are most probably located around 2 km below the summit, a water droplet (liquid water) may not exist at this source depth. We may therefore reasonably assume that the fluid at the source of the LP events is an ash-gas mixture. We propose that an ash-laden gas was injected into a closed conduit (pre-existing crack) just above the magmatic system, causing the resonance of the conduit or an LP event. This process repeatedly occurred and accumulated ash particles in the conduit, generating the temporal variations in the frequency and Q of the LP events. Finally, the conduit was almost filled

  16. Early Eocene volcanic ashes on Greifswalder Oie and their depositional environment, with an overview of coeval ash-bearing deposits in northern Germany and Denmark

    NASA Astrophysics Data System (ADS)

    Obst, Karsten; Ansorge, Jörg; Matting, Sabine; Hüneke, Heiko

    2015-11-01

    Unconsolidated bentonites and carbonate-cemented volcanic ashes occur in northern Germany within the clay sequence of the Lamstedt and Schlieven Formations documented by several wells. Ash-bearing carbonate concretions (so-called cementstones) are also known from glacially transported rafts and erratic boulders on the Baltic Sea island Greifswalder Oie, representing the easternmost exposures of early Eocene sediments in the North Sea Basin. The ashes can be correlated with water-lain ashes of the Danish Fur and Ølst Formations (mo-clay) generated during the opening of the North Atlantic Ocean about 55 Ma ago. Two types of cementstones can be distinguished on the basis of the mineralogical composition, sedimentary features and fossil content. Greifswalder Oie type I contains a black, up to 12-cm-thick ash deposit that follows above two distinct thin grey ash layers. The major ash unit has a rather homogeneous lower part; only a very weak normal grading and faint lamination are discernible. In the upper part, however, intercalations with light mudstone, in part intensively bioturbated, together with parallel and cross-lamination suggest reworking of the ash in a shallow marine environment. Major and trace element compositions are used to correlate type I ashes with those of the Danish-positive series which represent rather uniform ferrobasalts of the Danish stage 4, probably related to the emergence of proto-Iceland. In contrast, type II ash comprises a single, normally graded, about 5-cm-thick layer of water-lain air-fall tuff, which is embedded in fine-grained sandstone to muddy siltstone. Type II ash is characterised by very high TiO2 but low MgO contents. Exceptional REE patterns with a pronounced positive Eu anomaly suggest intense leaching of the glass that hampers exact correlation with pyroclastic deposits within the North Atlantic Igneous Province.

  17. Heterogeneous photochemistry of oxalic acid on Mauritanian sand and Icelandic volcanic ash.

    PubMed

    Styler, Sarah A; Donaldson, D J

    2012-08-21

    Teragram quantities of crustal and volcanic aerosol are released into the atmosphere on an annual basis. Although these substrates contain photoactive metal oxides, little is known about the role that they may play in catalyzing the heterogeneous phototransformation of semivolatile organic species. In the present study, we have investigated oxalic acid photochemistry at the surface of Fe(2)O(3), TiO(2), Mauritanian sand, and Icelandic volcanic ash in the presence and absence of oxygen using a photochemical Knudsen cell reactor. Illumination of all sample types resulted in the production of gas-phase CO(2). In the case of Mauritanian sand, the production of gas-phase CO(2) scaled with the loss of surface oxalic acid. In the absence of oxygen, the production of CO(2) by the sand and ash films scaled with the absorption spectrum of iron oxalate, which suggests that the reaction is at least in part iron-mediated. The presence of oxygen suppressed CO(2) production at the Fe(2)O(3) surface, enhanced CO(2) production at the Mauritanian sand surface, and did not have a net effect upon CO(2) production at the Icelandic ash surface. These different oxygen dependencies imply that oxalic acid photochemistry at the authentic surfaces under study was not solely iron-mediated. Experiments at the TiO(2) surface, which showed enhanced CO(2) production from oxalic acid in the presence of oxygen, suggest that Ti-mediated photochemistry played an important role. In summary, these results provide evidence that solid-phase aerosol photochemistry may influence the atmospheric lifetime of oxalic acid in arid regions, where its removal via wet deposition is insignificant.

  18. HCl uptake by volcanic ash in the high temperature eruption plume: Mechanistic insights

    NASA Astrophysics Data System (ADS)

    Ayris, Paul M.; Delmelle, Pierre; Cimarelli, Corrado; Maters, Elena C.; Suzuki, Yujiro J.; Dingwell, Donald B.

    2014-11-01

    The injection of HCl into the stratosphere by large volcanic eruptions has long been considered to be of minor importance. This is due to the widespread assumption that any HCl will be efficiently taken up by hydrometeors in the cooling plume. However, this assumption does not account for the possibility that prior scavenging processes can act within the high temperature core of the eruption plume. The adsorption of HCl onto ash surfaces to form soluble -Cl salts is a hitherto unconstrained scavenging mechanism, and their fate within the atmosphere and environment is uncertain. Here, we investigate the capacity of volcanic glasses of tephrite, phonolite, dacite and rhyolite composition to adsorb HCl. The experiments are conducted in the presence of He-SO2-CO2 mixtures at temperatures of 200-800 °C. Our experimental findings show that only the tephrite and phonolite glasses exhibit significant reactivity to HCl, which show optimal efficiency of uptake at 400-600 °C. The primary reaction product formed during adsorption is halite (NaCl), in addition to minor quantities of Ca-, K-, Al- and Fe-bearing chlorides. Uptake of HCl by glass surfaces is sustained by the outward diffusion of Na+ and other Cl-reactive cations via exchange with H+. Simple mathematical models can be used to yield Na diffusion coefficients for the four experimental glasses, and suggest that a varying structural role for Na within the glass network governs the capacity for HCl retention. The uptake of HCl under experimental conditions is limited above 500 °C by a Cl-induced dehydroxylation process, but the presence of H2O in the hydrous plume may sustain or even enhance adsorption. The present experimental data, combined with cooling gradients obtained from established plume evolution models, lead us to conclude that HCl adsorption within the eruption plume core can be a more significant scavenging mechanism in large explosive eruptions than previously considered. We additionally highlight the

  19. Development of an automatic volcanic ash sampling apparatus for active volcanoes

    NASA Astrophysics Data System (ADS)

    Shimano, Taketo; Nishimura, Takeshi; Chiga, Nobuyuki; Shibasaki, Yoshinobu; Iguchi, Masato; Miki, Daisuke; Yokoo, Akihiko

    2013-12-01

    We develop an automatic system for the sampling of ash fall particles, to be used for continuous monitoring of magma ascent and eruptive dynamics at active volcanoes. The system consists of a sampling apparatus and cameras to monitor surface phenomena during eruptions. The Sampling Apparatus for Time Series Unmanned Monitoring of Ash (SATSUMA-I and SATSUMA-II) is less than 10 kg in weight and works automatically for more than a month with a 10-kg lead battery to obtain a total of 30 to 36 samples in one cycle of operation. The time range covered in one cycle varies from less than an hour to several months, depending on the aims of observation, allowing researchers to target minute-scale fluctuations in a single eruptive event, as well as daily to weekly trends in persistent volcanic activity. The latest version, SATSUMA-II, also enables control of sampling parameters remotely by e-mail commands. Durability of the apparatus is high: our prototypes worked for several months, in rainy and typhoon seasons, at windy and humid locations, and under strong sunlight. We have been successful in collecting ash samples emitted from Showa crater almost everyday for more than 4 years (2008-2012) at Sakurajima volcano in southwest Japan.

  20. Particle morphologies and formation mechanisms of fine volcanic ash aerosol collected from the 2006 eruption of Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Rinkleff, P. G.; Cahill, C. F.

    2010-12-01

    Fine volcanic ash aerosol (35-0.09um) erupted in 2006 by Augustine Volcano, southwest of Anchorage, Alaska was collected by a DRUM cascade impactor and analyzed by scanning electron microscopy for individual particle chemistry and morphology. Results of these analyses show ash particles occur as either individual glass shard and mineral phase (plagioclase, magnetite, ilmenite, hornblende, etc.) particles or aggregates thereof. Individual glass shard ash particles are angular, uniformly-sized, consist of calc-alkaline whole-rock elements (Si, Al, Fe, Na, and Ca) and are not collocated on the sample media with non-silicate, Cl and S bearing sea salt particles. Aggregate particles occur as two types: pure ash aggregates and sea salt-cored aggregates. Pure ash aggregates are made up of only ash particles and contain no other constituents. Sea salt-cored aggregates are ash particles commingled with sea salts. Determining the formation processes of the different ash particle types need further investigation but some possibilities are proposed here. Individual ash particles may exist when the ambient air is generally dry, little electrical charge exists on ash particles, the eruptive cloud is generally dry, or the number of individual particles exceeds the scavenging capacity of the water droplets present. Another possibility is that ash aggregates may break apart as relative humidity drops over time and causes ash-laden water droplets to evaporate and subsequently break apart. Pure ash aggregates may form when the ambient air and plume is relatively dry but the ash has a significant charge to cause ash to aggregate. Or they could form during long-range transport when turbulent or Brownian motion can cause ash particles to collide and coagulate. Pure ash aggregates could also form as a result of water droplet scavenging and subsequent evaporation of water droplets, leaving behind only ash. In this case, droplets would not have interacted with a sea salt

  1. Airborne EM survey in volcanoes : Application to a volcanic hazards assessment

    NASA Astrophysics Data System (ADS)

    Mogi, T.

    2010-12-01

    Airborne electromagnetics (AEM) is a useful tool for investigating subsurface structures of volcanoes because it can survey large areas involving inaccessible areas. Disadvantages include lower accuracy and limited depth of investigation. AEM has been widely used in mineral exploration in frontier areas, and have been applying to engineering and environmental fields, particularly in studies involving active volcanoes. AEM systems typically comprise a transmitter and a receiver on an aircraft or in a towed bird, and although effective for surveying large areas, their penetration depth is limited because the distance between the transmitter and receiver is small and higher-frequency signals are used. To explore deeper structures using AEM, a semi-airborne system called GRounded Electrical source Airborne Transient ElectroMagnetics (GREATEM) has been developed. The system uses a grounded-electrical-dipole as the transmitter and generates horizontal electric fields. The GREATEM technology, first proposed by Mogi et al. (1998), has recently been improved and used in practical surveys (Mogi et al., 2009). The GREATEM survey system was developed to increase the depth of investigation possible using AEM. The method was tested in some volcanoes at 2004-2005. Here I will talk about some results of typical AEM surveys and GREATEM surveys in some volcanoes in Japan to mitigate hazards associated with volcano eruption. Geologic hazards caused by volcanic eruptions can be mitigated by a combination of prediction, preparedness and land-use control. Risk management depends on the identification of hazard zones and forecasting of eruptions. Hazard zoning involves the mapping of deposits which have formed during particular phases of volcanic activity and their extrapolation to identify the area which would be likely to suffer a similar hazard at some future time. The mapping is usually performed by surface geological surveys of volcanic deposits. Resistivity mapping by AEM is useful

  2. Volcanic Ash Hazards and Risk in Argentina: Scientific and Social Collaborative Approaches.

    NASA Astrophysics Data System (ADS)

    Rovere, E. I., II; Violante, R. A.; Vazquez Herrera, M. D.; Martinez Fernandez, M. D. L. P.

    2015-12-01

    Due to the absence of alerts or volcanic impacts during 60 years (from 1932, Quizapu-Descabezado Grande -one of the major eruptions of the XX Century- until 1991 Hudson eruption) there was mild remembrance of volcanic hazards in the collective memory of the Argentina citizens. Since then and until April 2015, the social perception changed according to different factors: age, location, education, culture, vulnerability. This variability produces a maze of challenges that go beyond the scientific knowledge. Volcanic health hazards began to be understood in 2008 after the eruption of Chaiten volcano. The particle size of ashfall (<10 μ) and the silica composition were the main factors of concern on epidemiological monitoring. In 2011 the volcanic complex Puyehue - Cordon Caulle eruption produced ashfall through plumes that reached densely populated cities like San Carlos de Bariloche and Buenos Aires. Farther away in South Africa and New Zealand ash plumes forced airlines to cancel local and international flights for several weeks. The fear of another eruption did not wait long when Calbuco volcano started activity in April 2015, it came at a time when Villarrica volcano was also in an eruptive phase, and the SERNAGEOMIN Chile, through the Observatory OVDAS of the Southern Andes, faced multiple natural disasters at the same time, 3 volcanoes in activity, lahars, pyroclastic flows and floods in the North. In Argentina, critical infrastructure, farming, livestock and primary supplies were affected mainly in the western region. Copahue volcano, is increasing unstability on seismic and geochemistry data since 2012. Caviahue resort village, distant only 8 Km. from the active vent happens to be a high vulnerable location. In 2014 GEVAS (Geology, Volcanoes, Environment and Health) Network ARGENTINA Civil Association started collaborative activities with SEGEMAR and in 2015 with the IAPG (Geoethics, Argentina), intending to promote Best Practices in volcanic and geological

  3. Modeling volcanic ash resuspension - application to the 14-18 October 2011 outbreak episode in central Patagonia, Argentina

    NASA Astrophysics Data System (ADS)

    Folch, A.; Mingari, L.; Osores, M. S.; Collini, E.

    2014-01-01

    Volcanic fallout deposits from the June 2011 Cordón Caulle eruption on central Patagonia were remobilized in several occasions months after their emplacement. In particular, during 14-18 October 2011, an intense outbreak episode generated widespread volcanic clouds that were dispersed across Argentina, causing multiple impacts in the environment, affecting the air quality and disrupting airports. Fine ash particles in volcanic fallout deposits can be resuspended under favorable meteorological conditions, particularly during strong wind episodes in arid environments with low soil moisture and poor vegetation coverage. As opposed to eruption-formed ash clouds, modeling of resuspension-formed ash clouds has received little attention. In consequence, there are no emission schemes specially developed and calibrated for resuspended volcanic ash, and few operational products exists to model and forecast the formation and dispersal of resuspension ash clouds. Here we implement three dust emission schemes of increasing complexity in the FALL3D tephra dispersal model and use the 14-18 October 2011 outbreak episode as a model test case. We calibrate the emission schemes and validate the results of the coupled WRF-ARW (Weather Research and Forecasting - Advanced Research WRF)/FALL3D modeling system using satellite imagery and measurements of visibility (a quantity related to total suspended particle concentration at the surface) and particulate matter (PM10) concentration at several meteorological and air quality stations located at Argentina and Uruguay. Our final goal is to test the capability of the modeling system to become, in the near future, an operational forecast product for volcanic ash resuspension events.

  4. Improvements on Near Real Time Detection of Volcanic Ash Emissions for Emergency Monitoring with Limited Satellite Bands

    NASA Astrophysics Data System (ADS)

    Steensen, Torge; Webley, Peter; Dehn, Jon

    2014-05-01

    Quantifying volcanic ash emissions syn-eruptively is an important task for the global aviation community. However, due to the near real time nature of volcano monitoring, many parameters important for accurate ash mass estimates cannot be obtained easily. Previous studies highlight the surface temperature, the refractive index of the ash and the cloud top temperature as most crucial of these values. Even when estimating those parameters best possible, uncertainties associated with the ash masses remain high, especially when the satellite data is only available in the traditional 10.8 and 12.0 µm bands. To counteract this limitation, we developed a quantitative comparison between the ash extents in satellite and model data. The main aspect is to manually define the cloud edge based on the available satellite data as well as other knowledge like pilot reports or ground-based observations. This manual aspect, although subjective to the experience of the observer, can show a significant improvement as it provides the ability to highlight ash that otherwise would be obscured by meteorological clouds or, by passing over different surfaces with unaccounted temperatures, might be lost entirely and thus remains undetectable for an automated satellite approach. We show comparisons to Volcanic Ash Transport and Dispersion models and outline a quantitative match as well as percentages of overestimates based on satellite or dispersion model data which can be converted into a level of reliability for near real time volcano monitoring.

  5. FPLUME-1.0: An integral volcanic plume model accounting for ash aggregation

    NASA Astrophysics Data System (ADS)

    Folch, A.; Costa, A.; Macedonio, G.

    2016-02-01

    Eruption source parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D (one-dimensional) cross-section-averaged eruption column model based on the buoyant plume theory (BPT). The model accounts for plume bending by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in the presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an effective grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the effective particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland). The modular structure of the code facilitates the implementation in the future code versions of more quantitative ash aggregation parameterization as further observations and experiment data will be available for better constraining ash aggregation processes.

  6. FPLUME-1.0: An integral volcanic plume model accounting for ash aggregation

    NASA Astrophysics Data System (ADS)

    Folch, Arnau; Costa, Antonio; Macedonio, Giovanni

    2016-04-01

    Eruption Source Parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1D cross-section averaged eruption column model based on the Buoyant Plume Theory (BPT). The model accounts for plume bending by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an "effective" grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice-versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the "effective" particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland). The modular structure of the code facilitates the implementation in the future code versions of more quantitative ash aggregation parameterization as further observations and experiments data will be available for better constraining ash aggregation processes.

  7. First airborne samples of a volcanic plume for δ13C of CO2 determinations

    NASA Astrophysics Data System (ADS)

    Fischer, Tobias P.; Lopez, Taryn M.

    2016-04-01

    Volcanic degassing is one of the main natural sources of CO2 to the atmosphere. Carbon isotopes of volcanic gases enable the determination of CO2 sources including mantle, organic or carbonate sediments, and atmosphere. Until recently, this work required sample collection from vents followed by laboratory analyses. Isotope ratio infrared analyzers now enable rapid analyses of plume δ13C-CO2, in situ and in real time. Here we report the first analyses of δ13C-CO2 from airborne samples. These data combined with plume samples from the vent area enable extrapolation to the volcanic source δ13C. We performed our experiment at the previously unsampled and remote Kanaga Volcano in the Western Aleutians. We find a δ13C source composition of -4.4‰, suggesting that CO2 from Kanaga is primarily sourced from the upper mantle with minimal contributions from subducted components. Our method is widely applicable to volcanoes where remote location or activity level precludes sampling using traditional methods.

  8. Multi-sensor satellite monitoring of ash and SO2 volcanic plume in support to aviation control

    NASA Astrophysics Data System (ADS)

    Brenot, Hugues; Theys, Nicolas; Clarisse, Lieven; van Geffen, Jos; van Gent, Jeroen; Van Roozendael, Michel; van der A, Ronald; Hurtmans, Daniel; Coheur, Pierre-Francois; Clerbaux, Cathy; Valks, Pieter; Hedelt, Pascal; Prata, Fred; Rasson, Olivier; Sievers, Klaus; Zehner, Claus

    2014-05-01

    The 'Support to Aviation Control Service' (SACS; http://sacs.aeronomie.be) is an ESA-funded project hosted by the Belgian Institute for Space Aeronomy since 2007. The service provides near real-time (NRT) global volcanic ash and SO2 observations, as well as notifications in case of volcanic eruptions (success rate >95% for ash and SO2). SACS is based on the combined use of UV-visible (OMI, GOME-2 MetOp-A, GOME-2 MetOp-B) and infrared (AIRS, IASI MetOp-A, IASI MetOp-B) satellite instruments. The SACS service is primarily designed to support the Volcanic Ash Advisory Centers (VAACs) in their mandate to gather information on volcanic clouds and give advice to airline and air traffic control organisations. SACS also serves other users that subscribe to the service, in particular local volcano observatories, research scientists and airliner pilots. When a volcanic eruption is detected, SACS issues a warning that takes the form of a notification sent by e-mail to users. The SACS notification points to a dedicated web page where all relevant information is available and can be visualised with user-friendly tools. Information about the volcanic plume height from GOME-2 (MetOp-A and MetOp-B) are also available. The strength of a multi-sensor approach relies in the use of satellite data with different overpasses times, minimising the time-lag for detection and enhancing the reliability of such alerts. This presentation will give an overview of the SACS service, and of the different techniques used to detect volcanic plumes (ash, SO2 and plume height). It will also highlight the strengths and limitations of the service and measurements, and some perspectives.

  9. Atmospheric correction for satellite-based volcanic ash mapping and retrievals using ``split window'' IR data from GOES and AVHRR

    NASA Astrophysics Data System (ADS)

    Yu, Tianxu; Rose, William I.; Prata, A. J.

    2002-08-01

    Volcanic ash in volcanic clouds can be mapped in two dimensions using two-band thermal infrared data available from meteorological satellites. Wen and Rose [1994] developed an algorithm that allows retrieval of the effective particle size, the optical depth of the volcanic cloud, and the mass of fine ash in the cloud. Both the mapping and the retrieval scheme are less accurate in the humid tropical atmosphere. In this study we devised and tested a scheme for atmospheric correction of volcanic ash mapping and retrievals. The scheme utilizes infrared (IR) brightness temperature (BT) information in two infrared channels (both between 10 and 12.5 μm) and the brightness temperature differences (BTD) to estimate the amount of BTD shift caused by lower tropospheric water vapor. It is supported by the moderate resolution transmission (MODTRAN) analysis. The discrimination of volcanic clouds in the new scheme also uses both BT and BTD data but corrects for the effects of the water vapor. The new scheme is demonstrated and compared with the old scheme using two well-documented examples: (1) the 18 August 1992 volcanic cloud of Crater Peak, Mount Spurr, Alaska, and (2) the 26 December 1997 volcanic cloud from Soufriere Hills, Montserrat. The Spurr example represents a relatively ``dry'' subarctic atmospheric condition. The new scheme sees a volcanic cloud that is about 50% larger than the old. The mean optical depth and effective radii of cloud particles are lower by 22% and 9%, and the fine ash mass in the cloud is 14% higher. The Montserrat cloud is much smaller than Spurr and is more sensitive to atmospheric moisture. It also was located in a moist tropical atmosphere. For the Montserrat example the new scheme shows larger differences, with the area of the volcanic cloud being about 5.5 times larger, the optical depth and effective radii of particles lower by 56% and 28%, and the total fine particle mass in the cloud increased by 53%. The new scheme can be automated and

  10. The Detection, Characterization and Tracking of Recent Aleutian Island Volcanic Ash Plumes and the Assessment of Their Impact on Aviation

    NASA Technical Reports Server (NTRS)

    Murray, John J.; Hudnall, L. A.; Matus, A.; Krueger, A. J.; Trepte, C. r.

    2010-01-01

    The Aleutian Islands of Alaska are home to a number of major volcanoes which periodically present a significant hazard to aviation. During summer of 2008, the Okmok and Kasatochi volcanoes experienced moderate eruptive events. These were followed a dramatic, major eruption of Mount Redoubt in late March 2009. The Redoubt case is extensively covered in this paper. Volcanic ash and SO2 from each of these eruptions dispersed throughout the atmosphere. This created the potential for major problems for air traffic near the ash dispersions and at significant distances downwind. The NASA Applied Sciences Weather Program implements a wide variety of research projects to develop volcanic ash detection, characterization and tracking applications for NASA Earth Observing System and NOAA GOES and POES satellites. Chemistry applications using NASA AURA satellite Ozone Monitoring System (OMI) retrievals produced SO2 measurements to trace the dispersion of volcanic aerosol. This work was complimented by advanced multi-channel imager applications for the discrimination and height assignment of volcanic ash using NASA MODIS and NOAA GOES and POES imager data. Instruments similar to MODIS and OMI are scheduled for operational deployment on NPOESS. In addition, the NASA Calipso satellite provided highly accurate measurements of aerosol height and dispersion for the calibration and validation of these algorithms and for corroborative research studies. All of this work shortens the lead time for transition to operations and ensures that research satellite data and applications are operationally relevant and utilized quickly after the deployment of operational satellite systems. Introduction

  11. Volcanic Ash Cloud Altitude retrievals from passive satellite sensors: the 03-09 December 2015 Etna eruption.

    NASA Astrophysics Data System (ADS)

    corradini, stefano; merucci, luca; guerrieri, lorenzo; pugnaghi, sergio; mcgarragh, greg; carboni, elisa; ventress, lucy; grainger, roy; scollo, simona; pardini, federica; zaksek, klemen; langmann, baerbel; bancalá, severin; stelitano, dario

    2016-04-01

    The volcanic ash cloud altitude is one of the most important parameter needed for the volcanic ash cloud estimations (mass, effective radius and optical depth). It is essential by modelers to initialize the ash cloud transportation models, and by volcanologists to give insights into eruption dynamics. Moreover, it is extremely important in order to reduce the disruption to flights as a result of volcanic activity whilst still ensuring safe travel. In this work, the volcanic ash cloud altitude is computed from remote sensing passive satellite data (SEVIRI, MODIS, IASI and MISR) by using the most of the existing retrieval techniques. A novel approach, based on the CO2 slicing procedure, is also shown. The comparisons among different techniques are presented and advantages and drawbacks emphasized. As test cases Etna eruptions in the period between 03 and 09 December 2015 are considered. During this time four lava fountain events occurred at the Voragine crater, forming eruption columns higher than 12 km asl and producing copious tephra fallout on volcano flanks. These events, among the biggest of the last 20 years, produced emissions that reached the stratosphere and produced a circum-global transport throughout the northern hemisphere.

  12. Description and mineralogy of Tertiary volcanic ash partings and their relationship to coal seams, near Homer, Alaska

    SciTech Connect

    Reinink-Smith, L.M.

    1985-04-01

    Outcrops of Tertiary coal-bearing units in sea cliffs of the Kenai Peninsula provide an excellent study area for volcanic ash partings in coals. Twenty mid-to late-Miocene, 50-cm to 3-m thick coal seams exposed in the sea cliffs about 10 km west of Homer contain an average of 10 volcanic ash or lapilli tuff partings each. The bedding relationships of the coal with any one parting cannot be predicted, and the contacts of the partings with the coal range from very sharp to predominantly gradational. These bedding relationships provide clues about the surface on which the ashes fell and on which the coal was accumulating. For example, some ashes fell in standing water, others on irregular subaerial surfaces. The partings are in various stages of alteration to kaolinite and bentonite, and vary in thickness from a few millimeters to about 10 cm. The consistency and texture of the partings depend on the degree of alteration; the less altered partings display visible pumice fragments and euhedral feldspars, commonly within a finer grained matrix. Separate pumice fragments, excluding matrix, can also occur as partings in the coal. The more altered partings may be wet and plastic, or they may be well indurated claystones; the colors range from gray-yellow to dark brown. The indurated prints are more common in older part of the section. The coal seams may be capped by volcanic ash partings and are commonly underlain by a pencil shale of nonvolcanic origin.

  13. Results from Volcanic Ash Aerosol Collection and Analysis from the Recent Eruptions of Pavlof, Okmok, and Kasatochi Volcanoes, Alaska

    NASA Astrophysics Data System (ADS)

    Rinkleff, P. G.; Cahill, C. F.

    2009-12-01

    Pavlof Volcano, on the Alaska Peninsula SW of Anchorage, Alaska, erupted during Fall 2007; the Aleutian volcanoes, Okmok and Kasatochi, erupted during late Summer 2008. These eruptions sent ash plumes into the North Pacific Ocean, disrupting regional air traffic, and sending ash into nearby communities. The eruptions of Pavlof and Okmok occurred over several weeks and both had waning phases dominated by low level ash emissions. Kasatochi erupted on 7 August 2009 over a period of seven days in large, short, discrete pulses. Fine ash (2.5 - 0.1 micrometer in aerodynamic diameter) from these eruptions was collected using DRUM aerosol impactors. Aerosol samples were analyzed for mass by β-gauge and elemental composition by synchrotron x-ray fluorescence. Aerosols collected during the waning phase of the eruption of Pavlof from 27 August through 2 September 2007 and the eruption of Okmok Volcano 23 July through early August 2008, show strong diurnal cycles in the concentration of ash reaching sampling locations; ash concentrations are highest in the morning and lowest in the early afternoon. Air transport models (HYSPLIT and PUFF) confirm the transport of ash from Pavlof Volcano to Sand Point, Alaska and from Okmok Volcano to Dutch Harbor, Alaska during this interval and show that stable meteorological conditions allowed for the downward mixing of volcanic aerosols to the sampling sites. Although no visible ash fallout was observed during aerosol sampling, these results demonstrate that volcanic ash was present in respirable size fractions downwind of the volcanoes even during periods of low ash emissions. In contrast to Pavlof and Okmok, the Kasatochi eruption was characterized by discrete, strong, short-lived pulses, not sustained low-level ash emissions like the waning phases of the Pavlof and Okmok eruptions. PUFF and HYSPLIT confirm ash from the eruption of Kasatochi was transported to Dutch Harbor. However, the ash collected from Kasatochi eruption pulses

  14. Measurements of the complex refractive index of volcanic ash at 450, 546.7, and 650 nm

    NASA Astrophysics Data System (ADS)

    Ball, J. G. C.; Reed, B. E.; Grainger, R. G.; Peters, D. M.; Mather, T. A.; Pyle, D. M.

    2015-08-01

    The detection and quantification of volcanic ash is extremely important to the aviation industry, civil defense organizations, and those in peril from volcanic ashfall. To exploit the remote sensing techniques that are used to monitor a volcanic cloud and return information on its properties, the effective complex refractive index of the volcanic ash is required. This paper presents the complex refractive index determined in the laboratory at 450.0 nm, 546.7 nm, and 650.0 nm for volcanic ash samples from eruptions of Aso (Japan), Grímsvötn (Iceland), Chaitén (Chile), Etna (Italy), Eyjafjallajökull (Iceland), Tongariro (New Zealand), Askja (Iceland), Nisyros (Greece), Okmok (Alaska), Augustine (Alaska), and Spurr (Alaska). The Becke line method was used to measure the real part of the refractive index with an accuracy of 0.01. The values measured differed between eruptions and were in the range 1.51-1.63 at 450.0 nm, 1.50-1.61 at 546.7 nm, and 1.50-1.59 at 650.0 nm. A novel method is introduced to derive the imaginary part of the refractive index from the attenuation of light by ash. The method has a precision in the range 10-3-10-4. The values for the ash imaginary refractive index ranged 0.22-1.70 × 10-3 at 450.0 nm, 0.16-1.93 × 10-3 at 546.7 nm, and 0.15-2.08 × 10-3 at 650.0 nm. The accuracy of Becke and attenuation methods was assessed by measuring the complex refractive index of Hoya neutral density glass and found to have an accuracy of <0.01 and <2 × 10-5 for the real and imaginary parts of the refractive index, respectively.

  15. Sakurajima volcano: a physico-chemical study of the health consequences of long-term exposure to volcanic ash

    NASA Astrophysics Data System (ADS)

    Hillman, S. E.; Horwell, C. J.; Densmore, A. L.; Damby, D. E.; Fubini, B.; Ishimine, Y.; Tomatis, M.

    2012-05-01

    Regular eruptions from Sakurajima volcano, Japan, repeatedly cover local urban areas with volcanic ash. The frequency of exposure of local populations to the ash led to substantial concerns about possible respiratory health hazards, resulting in many epidemiological and toxicological studies being carried out in the 1980s. However, very few mineralogical data were available for determination of whether the ash was sufficiently fine to present a respiratory hazard. In this study, we review the existing studies and carry out mineralogical, geochemical and toxicological analyses to address whether the ash from Sakurajima has the potential to cause respiratory health problems. The results show that the amount of respirable (<4 μm) material produced by the volcano is highly variable in different eruptions (1.1-18.8 vol.%). The finest samples derive from historical, plinian eruptions but considerable amounts of respirable material were also produced from the most recent vulcanian eruptive phase (since 1955). The amount of cristobalite, a crystalline silica polymorph which has the potential to cause chronic respiratory diseases, is ~3-5 wt.% in the bulk ash. Scanning electron microscope and transmission electron microscope imaging showed no fibrous particles similar to asbestos particles. Surface reactivity tests showed that the ash did not produce significant amounts of highly reactive hydroxyl radicals (0.09-1.35 μmol m-2 at 30 min.) in comparison to other volcanic ash types. A basic toxicology assay to assess the ability of ash to rupture the membrane of red blood cells showed low propensity for haemolysis. The findings suggest that the potential health hazard of the ash is low, but exposure and respiratory conditions should still be monitored given the high frequency and durations of exposure.

  16. Coupling a Lagrangian Dispersion Model and Remote Sensing Data for Quantification of Volcanic Ash Transport and Deposition

    NASA Astrophysics Data System (ADS)

    Peterson, R. A.; Dean, K.

    2003-12-01

    Use of remote sensing techniques, particularly the band 4 (10.3-11.3 μ m) minus band 5 (11.5-12.5 μ m) "split-window", is the predominant method for monitoring the long-term movement of airborne volcanic emissions such as ash, water vapor, and other gases. The split-window technique works well for moderately concentrated clouds, and there are methods based on radiative transfer that may provide quantitative information about total mass and particle size (Wen and Rose, 1994). However atmospheric dispersion, sedimentation and wet deposition eventually lead to the loss of discernible signals in the split window. Fortunately, numerical dispersion models do not have a low-concentration limit and are capable of longer term tracking. Model simulations also provide relative concentration changes with time. Only after post-event analysis is it possible to obtain quantitative concentration information as a function of space and time. A new technique combining remote sensing data with model simulations which may help provide near real-time information of cloud concentrations has been developed. This technique uses information gathered from several relatively recent eruptions for which total eruption volume and fallout distributions have been determined. Using the fallout distribution measurements and model simulations, the deposition rates at a function of location and time can be calculated. Combining this information with net eruption volume, ash cloud concentrations can be quantified from the model simulations and further correlated with the remote sensing data. The low-concentration limit of the split-window technique can then be obtained. Using this information, cloud concentrations can be obtained from model simulations for cases when concentration levels are too low or remote sensing data is simply not available. Although the required data for this technique is somewhat scare, initial results are encouraging and will be discussed. The results from this technique will

  17. The generation of lighting in volcanic plumes: The microphysics of ash triboelectric charging

    NASA Astrophysics Data System (ADS)

    Mendez, J. S.; Dufek, J.

    2013-12-01

    The spectacular lightning strokes observed during eruptions testify to the enormous potentials that can be generated within plumes. Related to the charging of individual ash particles, large electric fields and volcanic lightning have been observed at Eyjafjallajokull, Redoubt, and Sakurajima, among other volcanoes. A number of mechanisms have been proposed for plume electrification. These include charging from the brittle failure of rock, charging due to phase change as material is carried aloft, and triboelectric charging. While the first two mechanisms (fracto-emission and volatile charging) have been described by other authors (James et al, 2000 and McNutt et al., 2010, respectively), the physics of tribocharging--charging caused by the collisions of particles--of ash are still relatively unknown. In the present work, we describe two sets of experiments designed to explore what controls the exchange of charge during particle collisions. The first set of experiments was designed to determine the transient electrostatic behavior of a parcel of ash. Succinctly, the experiments consist of fluidizing an ash bed with nitrogen and monitoring the resulting currents induced in a monopole probe by the moving particles. It is important to note that the reaction chamber only allows particle-particle interactions. The entire experimental setup is enclosed in a vacuum chamber, allowing us to carefully control the environment during experiments. The second experimental apparatus allows us measure how much charge is exchanged during a single particle-particle collision. Capable of measuring charges as small as 1 fC, this device allows us to methodically to characterize charges on particles smaller than 100 microns. Previous work (Forward et al. 2009) has demonstrated that charging is often enhanced when the particle system is less homogeneous. Indeed, our experiments have shown that mixtures of two substances can produce greater electrification by almost an order of magnitude

  18. Particle size distribution and PM10 of volcanic ashes in Guadeloupe during the major eruption of Soufrière Hills in February 2010

    NASA Astrophysics Data System (ADS)

    Molinie, Jack; Bernard, Marie-Lise; Komorowski, Jean-Christophe; Euphrasie-Clotilde, Lovely; Brute, France-Nor; Roussas, Andre

    2014-05-01

    On the 11 February 2010, fifteen minutes after midday, an explosive eruption of Soufriere Hills volcano sent tephra over the neighbour Caribbean islands. The volcanic ashes benefit from the vertical wind distribution of the moment to reach Guadeloupe island and cover it ground near 5 hours after the ash venting. Since the first ashes arrival over the town of Pointe-a-Pitre (located at 80 km at the South East of Soufriere hills volcano) to the end of the event, we measured the mean particle concentrations and particle size distributions every twenty minutes. Measurements were performed at a building roof of the town using an optical particles counter Lighthouse IAQ 3016 mainly used in indoor air quality studies and which provides up to 6 particle size channels of simultaneous counting with aerodynamic diameters classes ranging from 0.3 to >10 µm. The airborne particulate matter mass concentration, with equivalent aerodynamic diameters less than 10 µm (PM10) were measured by the local air quality network Gwad'air, in the vicinity of the site used to study this ash fall.. The maximum concentration of small particles with diameter lesser than 1µm (D0.3-1) was observed one hour before the larger particles. This result may imply a difference in shape and density between particles D0.3-1 and particles D1-10 (1volcanic ashes which impacts on the exposed population, especially their

  19. Forecasting volcanic ash dispersal and coeval resuspension during the April-May 2015 Calbuco eruption

    NASA Astrophysics Data System (ADS)

    Reckziegel, F.; Bustos, E.; Mingari, L.; Báez, W.; Villarosa, G.; Folch, A.; Collini, E.; Viramonte, J.; Romero, J.; Osores, S.

    2016-07-01

    Atmospheric dispersion of volcanic ash from explosive eruptions or from subsequent fallout deposit resuspension causes a range of impacts and disruptions on human activities and ecosystems. The April-May 2015 Calbuco eruption in Chile involved eruption and resuspension activities. We overview the chronology, effects, and products resulting from these events, in order to validate an operational forecast strategy for tephra dispersal. The modelling strategy builds on coupling the meteorological Weather Research and Forecasting (WRF/ARW) model with the FALL3D dispersal model for eruptive and resuspension processes. The eruption modelling considers two distinct particle granulometries, a preliminary first guess distribution used operationally when no field data was available yet, and a refined distribution based on field measurements. Volcanological inputs were inferred from eruption reports and results from an Argentina-Chilean ash sample data network, which performed in-situ sampling during the eruption. In order to validate the modelling strategy, results were compared with satellite retrievals and ground deposit measurements. Results indicate that the WRF-FALL3D modelling system can provide reasonable forecasts in both eruption and resuspension modes, particularly when the adjusted granulometry is considered. The study also highlights the importance of having dedicated datasets of active volcanoes furnishing first-guess model inputs during the early stages of an eruption.

  20. FPLUME-1.0: An integrated volcanic plume model accounting for ash aggregation

    NASA Astrophysics Data System (ADS)

    Folch, A.; Costa, A.; Macedonio, G.

    2015-09-01

    Eruption Source Parameters (ESP) characterizing volcanic eruption plumes are crucial inputs for atmospheric tephra dispersal models, used for hazard assessment and risk mitigation. We present FPLUME-1.0, a steady-state 1-D cross-section averaged eruption column model based on the Buoyant Plume Theory (BPT). The model accounts for plume bent over by wind, entrainment of ambient moisture, effects of water phase changes, particle fallout and re-entrainment, a new parameterization for the air entrainment coefficients and a model for wet aggregation of ash particles in presence of liquid water or ice. In the occurrence of wet aggregation, the model predicts an "effective" grain size distribution depleted in fines with respect to that erupted at the vent. Given a wind profile, the model can be used to determine the column height from the eruption mass flow rate or vice-versa. The ultimate goal is to improve ash cloud dispersal forecasts by better constraining the ESP (column height, eruption rate and vertical distribution of mass) and the "effective" particle grain size distribution resulting from eventual wet aggregation within the plume. As test cases we apply the model to the eruptive phase-B of the 4 April 1982 El Chichón volcano eruption (México) and the 6 May 2010 Eyjafjallajökull eruption phase (Iceland).

  1. Future developments in modelling and monitoring of volcanic ash clouds: outcomes from the first IAVCEI-WMO workshop on Ash Dispersal Forecast and Civil Aviation

    NASA Astrophysics Data System (ADS)

    Bonadonna, Costanza; Folch, Arnau; Loughlin, Susan; Puempel, Herbert

    2012-01-01

    As a result of the serious consequences of the 2010 Eyjafjallajökull eruption (Iceland) on civil aviation, 52 volcanologists, meteorologists, atmospheric dispersion modellers and space and ground-based monitoring specialists from 12 different countries (including representatives from 6 Volcanic Ash Advisory Centres and related institutions) gathered to discuss the needs of the ash dispersal modelling community, investigate new data-acquisition strategies (i.e. quantitative measurements and observations) and discuss how to improve communication between the research community and institutions with an operational mandate. Based on a dedicated benchmark exercise and on 3 days of in-depth discussion, recommendations have been made for future model improvements, new strategies of ash cloud forecasting, multidisciplinary data acquisition and more efficient communication between different communities. Issues addressed in the workshop include ash dispersal modelling, uncertainty, ensemble forecasting, combining dispersal models and observations, sensitivity analysis, model variability, data acquisition, pre-eruption forecasting, first simulation and data assimilation, research priorities and new communication strategies to improve information flow and operational routines. As a main conclusion, model developers, meteorologists, volcanologists and stakeholders need to work closely together to develop new and improved strategies for ash dispersal forecasting and, in particular, to: (1) improve the definition of the source term, (2) design models and forecasting strategies that can better characterize uncertainties, (3) explore and identify the best ensemble strategies that can be adapted to ash dispersal forecasting, (4) identify optimized strategies for the combination of models and observations and (5) implement new critical operational strategies.

  2. Partial Collapse of Plinian Volcanic Jets and the Production of Multiply Layered Ash Clouds

    NASA Astrophysics Data System (ADS)

    Gilchrist, J. T.; Jellinek, M.

    2014-12-01

    Powerful explosive volcanic eruptions inject ash high into the atmosphere, which spreads as an intrusion to form characteristic umbrella-shaped clouds. An enigmatic feature of a number of recent eruption clouds (e.g. Popocatepetl, 2012; Soufriere Hills, 2010; Mt. St. Helens, 1980 and Puyehue, 2011) is that they are constructed of multiple layers (Figure 1, left). How such layering emerges within an advancing gravity current of initially well-mixed ash is unclear. Potential major controls include the strength and structure of the atmospheric density stratification, the particle size distribution within the ash cloud and the entrainment of ambient atmosphere into the rising plume. Accordingly, we conduct analog experiments in which saltwater jets with mono- and bi-disperse suspensions of fine and coarse silica particles are injected into a saltwater tank with a linear density stratification. Whereas classical umbrella clouds are produced for strong jets (low source Richardson number, -Ri0) under all particle-loading conditions, multiply layered clouds emerge for weak jets (high -Ri0) and relatively concentrated bi-disperse and coarse mono-disperse suspensions. In particular, at high -Ri0 coarse particles inhibit entrainment and enhance the partial collapse of rising jets to form gravity currents that intermittently descend along the jet margin and spread at varying neutral buoyancy heights to form layers. For high concentrations of coarse sand gravity currents can reach the tank floor. Collapse and compaction of this material to form a deposit expels buoyant interstitial fluid that rises to form additional layers below and within the overlying multiply layered cloud. One layer and multiply layered clouds have distinct depositional patterns and present unique risks to air traffic.

  3. Predicting and validating the tracking of a Volcanic Ash Cloud during the 2006 Eruption of Mt. Augustine Volcano

    SciTech Connect

    Webley, Peter W.; Atkinson, D.; Collins, Richard L.; Dean, K.; Fochesatto, J.; Sassen, Kenneth; Cahill, Catherine F.; Prata, A.; Flynn, Connor J.; Mizutani, K.

    2008-11-01

    On 11 January 2006, Mount Augustine volcano in southern Alaska began erupting after 20-year repose. The Anchorage Forecast Office of the National Weather Service (NWS) issued an advisory on 28 January for Kodiak City. On 31 January, Alaska Airlines cancelled all flights to and from Anchorage after multiple advisories from the NWS for Anchorage and the surrounding region. The Alaska Volcano Observatory (AVO) had reported the onset of the continuous eruption. AVO monitors the approximately 100 active volcanoes in the Northern Pacific. Ash clouds from these volcanoes can cause serious damage to an aircraft and pose a serious threat to the local communities, and to transcontinental air traffic throughout the Arctic and sub-Arctic region. Within AVO, a dispersion model has been developed to track the dispersion of volcanic ash clouds. The model, Puff, was used operational by AVO during the Augustine eruptive period. Here, we examine the dispersion of a volcanic ash cloud from Mount Augustine across Alaska from 29 January through the 2 February 2006. We present the synoptic meteorology, the Puff predictions, and measurements from aerosol samplers, laser radar (or lidar) systems, and satellites. UAF aerosol samplers revealed the presence of volcanic aerosols at the surface at sites where Puff predicted the ash clouds movement. Remote sensing satellite data showed the development of the ash cloud in close proximity to the volcano and a sulfur-dioxide cloud further from the volcano consistent with the Puff predictions. Lidars showed the presence of volcanic aerosol with consistent characteristics aloft over Alaska and were capable of detecting the aerosol, even in the presence of scattered clouds and where the cloud is too thin/disperse to be detected by remote sensing satellite data. The lidar measurements revealed the different trajectories of ash consistent with the Puff predictions. Dispersion models provide a forecast of volcanic ash cloud movement that might be

  4. Volcanic Gas

    MedlinePlus

    ... Hazards Tephra/Ash Lava Flows Lahars Volcanic Gas Climate Change Pyroclastic Flows Volcanic Landslides Preparedness Volcano Hazard Zones ... Please see our discussion of volcanic gases and climate change for additional information. Hydrogen sulfide (H 2 S) is ...

  5. Examining ash fall sequences in calk-alkaline subduction related volcanism, southern New Mexico

    NASA Astrophysics Data System (ADS)

    Rentz, S. P.; Michelfelder, G.; Salings, E. E.; Sikes, E. R.

    2015-12-01

    The Mogollon-Datil volcanic field (MDVF) is a 40-20 ma cluster of caldera activity in southern New Mexico tied to the subduction of oceanic lithosphere beneath the North American continental plate. The calk-alkaline magmatism of the three calderas in this field (Mogollon, Bursum, and Gila Cliff Dwellings) produced several voluminous regionally dispersed ash flow tuffs. This study will specifically examine the volcanic rocks: Cooney Formation (a compositionally zoned rhyolitic to quartz latite ash flow tuff containing quartz>k-feldspar>plagioclase>biotite, and pumice and lithic fragments. Rb ranges from 213-317ppm, Sr from 104-108ppm, and 87Sr/86Srm from 0.71326-0.71534), Davis Canyon Tuff (a phenocryst poor, high-silica rhyolite ash flow tuff containing sanidine>quartz>sodic plagioclase. Rb ranges from 214-230ppm, Sr from 42.2-63.2ppm, and 87Sr/86Srm from 0.71383-0.71464), and the Shelley Peak Tuff (a compositionally zoned, crystal-rich rhyolite tuff containing sodic plagioclase>minor sanidine>biotite>cpx. Rb ranges from 154-213ppm, Sr from 105-245ppm, and 87Sr/86Srm from 0.70944-0.7112) to further elucidate their petrogenic origins, attempt to determine if they may be of the same magmatic source, and yield data that could help model processes that would generate magma of these particular compositions. This study will examine compositional variation between the Davis Canyon, Shelley Peak and Cooney Tuffs and help with understanding the magma plumbing system during each eruption. More specifically, we will evaluate possible crustal components of these units, along with looking for geochemical signatures of arc or rift related magmatism. We will compare previous geochronology results (K-Ar and U-Pb fission track) and whole rock major and trace element geochemistry to data obtained via 40Ar/39Ar and U/Pb dates and new whole rock Sr, Nd and Pb isotopic ratios.

  6. Toxicity of volcanic-ash leachate to a blue-green alga. Results of a preliminary bioassay experiment

    USGS Publications Warehouse

    McKnight, Diane M.; Feder, G.L.; Stiles, E.A.

    1981-01-01

    To assess the possible effects of volcanic ash from the May 18,1980, eruption of Mt. St. Helens, Washington, on aquatic ecosystems, we conducted a bioassay experiment with a blue-green alga, Anabaena flos-aquae. Results showed that leachate (obtained by leaching 151 g of ash with 130 mL of simulated freshwater) was lethal to Anabaena flos-aquae cultures when diluted as much as 1:100 with culture medium. Cultures exposed to a 1:500 dilution grew, but a toxic effect was indicated by abnormalities in the Anabaena filaments. This study indicates that ash from the Mt. St. Helens volcano could have an effect on aquatic ecosystems in the areas of significant ashfall. Further study is needed to determine the toxic chemical constituents in the ash and also its possible effects on other aquatic organisms.

  7. Speciation analysis of antimony in extracts of size-classified volcanic ash by HPLC-ICP-MS.

    PubMed

    Miravet, R; López-Sánchez, J F; Rubio, R; Smichowski, P; Polla, G

    2007-03-01

    Although there is concern about the presence of toxic elements and their species in environmental matrices, for example water, sediment, and soil, speciation analysis of volcanic ash has received little attention. Antimony, in particular, an emerging element of environmental concern, has been less studied than other potentially toxic trace elements. In this context, a study was undertaken to assess the presence of inorganic Sb species in ash emitted from the Copahue volcano (Argentina). Antimony species were extracted from size-classified volcanic ash (<36 microm, 35-45 microm, 45-150 microm, and 150-300 microm) by use of 1 mol L(-1) citrate buffer at pH 5. Antimony(III) and (V) in the extracts were separated and quantified by high-performance liquid chromatography combined on-line with inductively coupled plasma mass spectrometry (HPLC-ICP-MS). Antimony species concentrations (microg g(-1)) in the four fractions varied from 0.14 to 0.67 for Sb(III) and from 0.02 to 0.03 for Sb(V). The results reveal, for the first time, the occurrence of both inorganic Sb species in the extractable portion of volcanic ash. Sb(III) was always the predominant species.

  8. Identifying the Volcanic Source of Disconnected Ash Clouds using the HYSPLIT Dispersion Model

    NASA Astrophysics Data System (ADS)

    Williams, D.; Ramsey, M. S.; Karimi, B.

    2013-12-01

    Monitoring of volcanic systems and their eruptive products can provide key insights into their hazard state and the processes occurring at depth. However, a large proportion of volcanic centers around the world are not actively monitored, especially those in remote regions. Some of these volcanoes are capable of producing devastating eruptions that emit ash plumes in excess of 10 km with little warning. Once erupted, these plumes can quickly become disconnected from their source making it difficult to determine their origin and assess the risk of continued activity, as well as creating ash-rich clouds that pose a serious risk to any aircraft in the region. Furthermore, some eruptions are not preceded by increased thermal activity (or these thermal anomalies are obscured by the plume) rendering traditional spaceborne thermal monitoring less effective. However, it may be possible to identify the source of the cloud using remote sensing data and trajectory modeling. Results could then be used to trigger imaging by higher spatial resolution sensors such as the Advanced Spacebourne Thermal Emission and Reflection Radiometer (ASTER) to detect activity. We attempt to trace ash cloud trajectories from three known eruptions (Chaiten, Kliuchevskoi, and Anatahan) with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model using the backward trajectory function. Ash cloud detection was obtained from the Moderate Resolution Imaging Spectroradiometer (MODIS) using the Brightness Temperature Difference (BTD) technique. Areas of high density within the cloud were assigned based on the BTD values, and were then classified. A grid of coordinate points from the cloud was made and each coordinate associated with the average density of its grid cell. Those cells with the highest average density were assigned a greater importance, and were the input coordinates for the HYSPLIT model. Three height levels were also chosen, associated with the troposphere, tropopause

  9. Episodic eruptions of volcanic ash trigger a reversible cascade of nuisance species outbreaks in pristine coral habitats.

    PubMed

    Schils, Tom

    2012-01-01

    Volcanically active islands abound in the tropical Pacific and harbor complex coral communities. Whereas lava streams and deep ash deposits are well-known to devastate coral communities through burial and smothering, little is known about the effect of moderate amounts of small particulate ash deposits on reef communities. Volcanic ash contains a diversity of chemical compounds that can induce nutrient enrichments triggering changes in benthic composition. Two independently collected data sets on the marine benthos of the pristine and remote reefs around Pagan Island, Northern Mariana Islands, reveal a sudden critical transition to cyanobacteria-dominated communities in 2009-2010, which coincides with a period of continuous volcanic ash eruptions. Concurrently, localized outbreaks of the coral-killing cyanobacteriosponge Terpios hoshinota displayed a remarkable symbiosis with filamentous cyanobacteria, which supported the rapid overgrowth of massive coral colonies and allowed the sponge to colonize substrate types from which it has not been documented before. The chemical composition of tephra from Pagan indicates that the outbreak of nuisance species on its reefs might represent an early succession stage of iron enrichment (a.k.a. "black reefs") similar to that caused by anthropogenic debris like ship wrecks or natural events like particulate deposition from wildfire smoke plumes or desert dust storms. Once Pagan's volcanic activity ceased in 2011, the cyanobacterial bloom disappeared. Another group of well-known nuisance algae in the tropical Pacific, the pelagophytes, did not reach bloom densities during this period of ash eruptions but new species records for the Northern Mariana Islands were documented. These field observations indicate that the study of population dynamics of pristine coral communities can advance our understanding of the resilience of tropical reef systems to natural and anthropogenic disturbances. PMID:23056381

  10. Episodic Eruptions of Volcanic Ash Trigger a Reversible Cascade of Nuisance Species Outbreaks in Pristine Coral Habitats

    PubMed Central

    Schils, Tom

    2012-01-01

    Volcanically active islands abound in the tropical Pacific and harbor complex coral communities. Whereas lava streams and deep ash deposits are well-known to devastate coral communities through burial and smothering, little is known about the effect of moderate amounts of small particulate ash deposits on reef communities. Volcanic ash contains a diversity of chemical compounds that can induce nutrient enrichments triggering changes in benthic composition. Two independently collected data sets on the marine benthos of the pristine and remote reefs around Pagan Island, Northern Mariana Islands, reveal a sudden critical transition to cyanobacteria-dominated communities in 2009–2010, which coincides with a period of continuous volcanic ash eruptions. Concurrently, localized outbreaks of the coral-killing cyanobacteriosponge Terpios hoshinota displayed a remarkable symbiosis with filamentous cyanobacteria, which supported the rapid overgrowth of massive coral colonies and allowed the sponge to colonize substrate types from which it has not been documented before. The chemical composition of tephra from Pagan indicates that the outbreak of nuisance species on its reefs might represent an early succession stage of iron enrichment (a.k.a. “black reefs”) similar to that caused by anthropogenic debris like ship wrecks or natural events like particulate deposition from wildfire smoke plumes or desert dust storms. Once Pagan's volcanic activity ceased in 2011, the cyanobacterial bloom disappeared. Another group of well-known nuisance algae in the tropical Pacific, the pelagophytes, did not reach bloom densities during this period of ash eruptions but new species records for the Northern Mariana Islands were documented. These field observations indicate that the study of population dynamics of pristine coral communities can advance our understanding of the resilience of tropical reef systems to natural and anthropogenic disturbances. PMID:23056381

  11. Densification kinetics of glassy and crystalline volcanic ash and subsequent predictability associated with its fragmentation

    NASA Astrophysics Data System (ADS)

    Vasseur, Jeremie; Wadsworth, Fabian; Lavallée, Yan; Hess, Kai-Uwe; Dingwell, Donald

    2014-05-01

    Explosive volcanism is one of the most catastrophic material failure phenomenon. During magma ascent fragmentation produces particulate magma which, if deposited above the glass transition of the interstitial melt, will sinter viscously. In-conduit tuffisites, conduit wall breccias and ash deposited from exceptionally hot pyroclastic flows are scenarios in which sintering by viscous flow is possible. Therefore, understanding the kinetics of sintering and the characteristic timescales over which magma densifies are critical to understanding the degassing timeframe in conduits and deposits. Viscous sintering is accompanied by a recovery of material strength toward that of a pore-free magma. Understanding damage mechanisms and seismic behaviour prior to failure of sintered volcanic products are also crucial for the application of micromechanical models and material failure forecasting laws. Powdered standard glass (NIST 717a) and natural volcanic ash have been used to explore sintering mechanisms at ambient pressure conditions and temporal evolution of connected and isolated pore-structure. We observed that sintering under low axial stress is essentially grain-size, surface tension and melt viscosity controlled. We found that the timescale over which the bulk density and the strength approaches that of pore-free melt at a given temperature is dependent on the grain-contact surface area, which can be estimated from the particle shape, the packing type and the initial total porosity. Granulometric constraint on the starting material indicates that the fraction of finer particles controls the rate of sintering as they cluster in pore spaces between larger particles and have a higher driving force for sintering due to their higher surface energy to volume ratio. In a volcano, newly formed sintering material will then further contribute to magma-plugging of the conduit and its mechanical properties will affect magma rupture and its associated precursory signals. This

  12. The bioreactivity of the sub-10 μm component of volcanic ash: Soufrière Hills volcano, Montserrat.

    PubMed

    Jones, Timothy; Bérubé, Kelly

    2011-10-30

    With the recent eruption of the Icelandic volcano Eyafallajökull and resulting ash cloud over much of Europe there was considerable concern about possible respiratory hazards. Volcanic ash can contain minerals that are known human respiratory health hazards such as cristobalite. Short-term ash exposures can cause skin sores, respiratory and ocular irritations and exacerbation of pre-existing lung conditions such as asthma. Long-term occupational level exposures to crystalline silicon dioxide can cause lung inflammation, oedema, fibrosis and cancer. The potential health effects would be dependent on factors including mineralogy, surface chemistry, size, and levels and duration of exposure. Bulk ash from the Soufrière Hills volcano was sourced and inhalable (<2.5 μm) ash samples prepared and physicochemically characterised. The fine ash samples were tested for bioreactivity by SDS-PAGE which determined the strength of binding between mineral grains and lung proteins. Selected proteins bound tightly to cristobalite, and bound loosely to other ash components. A positive correlation was seen between the amount of SiO(2) in the sample and the strength of the binding. The strength of binding is a function of the mineral's bioreactivity, and therefore, a potential geo-biomarker of respiratory risk. PMID:21872393

  13. Gigantic Ordovician volcanic ash fall in North America and Europe: Biological, tectonomagmatic, and event-stratigraphic significance

    SciTech Connect

    Huff, W.D. ); Bergstroem, S.M. ); Kolata, D.R. )

    1992-10-01

    Biostratigraphical, geochemical, isotopic, and paleogeographic data suggest that the Millbrig K-bentonite, one of the thickest and most widespread Ordovician volcanic ash beds in eastern North America, is the same as the so-called 'Big Bentonite' in Baltoscandia. This is the first time that the same K-bentonite has been identified in both North America and Europe, and it serves as a unique event-stratigraphic marker over a large portion of the Northern Hemisphere. This eruption produced at least 340 km[sup 3] of dense-rock-equivalent ash that was deposited in a layer up to 1-2 m thick over several million square kilometers. As much as 800 km[sup 3] of additional ash may have fallen into the Iapetus Ocean, for a total of 1,140 km[sup 3]. Trace element geochemistry shows that the ash was derived from a felsic calc-alkalic magmatic source characteristic of volcanism in a continental crust-based, destructive plate-margin setting. This is one of the largest, if not the largest, ash falls recorded in Earth's Phanerozoic stratigraphic record, but its recognizable effect on faunas and floras was minimal, and it did not result in a global extinction event. The Millbrig-Big Bentonite bed provides accurate time control for sedimentologic, paleoecologic, and paleogeographic reconstructions across plates positioned in tropical (Laurentia) and temperate (Baltica) latitudes during Middle Ordovician time.

  14. Influence of management practices on C stabilization pathways in agricultural volcanic ash soils (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Hernandez, Zulimar; María Álvarez, Ana; Carral, Pilar; de Figueiredo, Tomas; Almendros, Gonzalo

    2014-05-01

    Although C stabilization mechanisms in agricultural soils are still controversial [1], a series of overlapped pathways has been suggested [2] such as: i) insolubilization of low molecular weight precursors of soil organic matter (SOM) with reactive minerals through physical and chemical bonding, ii) selective accumulation of biosynthetic substances which are recalcitrant because of its inherent chemical composition, and iii) preservation and furter diagenetic transformation of particulate SOM entrapped within resistant microaggregates, where diffusion of soil enzymes is largely hampered. In some environments where carbohydrate and N compounds are not readily biodegraded, e.g., with water saturated micropores, an ill-known C stabilization pathway may involve the formation of Maillard's reaction products [3]. In all cases, these pathways converge in the formation of recalcitrant macromolecular substances, sharing several properties with the humic acid (HA) fraction [4]. In template forests, the selective preservation and further microbial reworking of plant biomass has been identified as a prevailing mechanism in the accumulation of recalcitrant SOM forms [5]. However, in volcanic ash soils with intense organomineral interactions, condensation reactions of low molecular weight precursors with short-range minerals may be the main mechanism [6]. In order to shed some light about the effect of agricultural management on soil C stabilization processes on volcanic ash soils, the chemical composition of HA and some structural proxies of SOM informing on its origin and potential resistance to biodegradation, were examined in 30 soils from Canary Islands (Spain) by visible, infrared (IR) and 13C nuclear magnetic resonance (NMR) spectroscopies, elementary analysis and pyrolytic techniques. The results of multivariate treatments, suggested at least three simultaneous C stabilization biogeochemical trends: i) diagenetic alteration of plant biomacromolecules in soils receiving

  15. Numerical Modelling of Volcanic Ash Settling in Water Using Adaptive Unstructured Meshes

    NASA Astrophysics Data System (ADS)

    Jacobs, C. T.; Collins, G. S.; Piggott, M. D.; Kramer, S. C.; Wilson, C. R.

    2011-12-01

    At the bottom of the world's oceans lies layer after layer of ash deposited from past volcanic eruptions. Correct interpretation of these layers can provide important constraints on the duration and frequency of volcanism, but requires a full understanding of the complex multi-phase settling and deposition process. Analogue experiments of tephra settling through a tank of water demonstrate that small ash particles can either settle individually, or collectively as a gravitationally unstable ash-laden plume. These plumes are generated when the concentration of particles exceeds a certain threshold such that the density of the tephra-water mixture is sufficiently large relative to the underlying particle-free water for a gravitational Rayleigh-Taylor instability to develop. These ash-laden plumes are observed to descend as a vertical density current at a velocity much greater than that of single particles, which has important implications for the emplacement of tephra deposits on the seabed. To extend the results of laboratory experiments to large scales and explore the conditions under which vertical density currents may form and persist, we have developed a multi-phase extension to Fluidity, a combined finite element / control volume CFD code that uses adaptive unstructured meshes. As a model validation, we present two- and three-dimensional simulations of tephra plume formation in a water tank that replicate laboratory experiments (Carey, 1997, doi:10.1130/0091-7613(1997)025<0839:IOCSOT>2.3.CO;2). An inflow boundary condition at the top of the domain allows particles to flux in at a constant rate of 0.472 gm-2s-1, forming a near-surface layer of tephra particles, which initially settle individually at the predicted Stokes velocity of 1.7 mms-1. As more tephra enters the water and the particle concentration increases, the layer eventually becomes unstable and plumes begin to form, descending with velocities more than ten times greater than those of individual

  16. Dust, volcanic ash, and the evolution of the South Pacific Gyre through the Cenozoic

    NASA Astrophysics Data System (ADS)

    Dunlea, Ann G.; Murray, Richard W.; Sauvage, Justine; Spivack, Arthur J.; Harris, Robert N.; D'Hondt, Steven

    2015-08-01

    We examine the 0-100 Ma paleoceanographic record retained in pelagic clay from the South Pacific Gyre (SPG) by analyzing 47 major, trace, and rare earth elements in bulk sediment in 206 samples from seven sites drilled during Integrated Ocean Drilling Program Expedition 329. We use multivariate statistical analyses (Q-mode factor analysis and multiple linear regression) of the geochemical data to construct a model of bulk pelagic clay composition and mass accumulation rates (MAR) of six end-members, (post-Archean average Australian shale, rhyolite, basalt, Fe-Mn-oxyhydroxides, apatite, and excess Si). Integrating the results with Co-based age models at Sites U1365, U1366, U1369, and U1370, we link changes in MAR of these components to global oceanographic, terrestrial, and climatic transformations through the Cenozoic. Our results track the spatial extent (thousands of kilometers) of dust deposition in the SPG during the aridification of Australia. Dispersed ash is a significant component of the pelagic clay, often comprising >50% by mass, and records episodes of Southern Hemisphere volcanism. Because both are transported by wind, the correlation of dust and ash MAR depends on the site's latitude and suggests meridional shifts in the position of atmospheric circulation cells. The hydrothermal MARs provide evidence for rapid deposition from the Osbourn Trough spreading ridge before it went extinct. Excess Si MARs show that the abrupt increase in siliceous productivity observed at Site U1371 also extended at least as far north as Sites U1369 and U1370, suggesting large-scale reorganizations of oceanic Si distributions ~10-8 Ma in the southern SPG.

  17. Performance of volcanic ash and pumice based blended cement concrete in mixed sulfate environment

    SciTech Connect

    Hossain, K.M.A. . E-mail: ahossain@ryerson.ca; Lachemi, M.

    2006-06-15

    The deterioration of concrete structures due to the presence of mixed sulfate in soils, groundwater and marine environments is a well-known phenomenon. The use of blended cements incorporating supplementary cementing materials and cements with low C{sub 3}A content is becoming common in such aggressive environments. This paper presents the results of an investigation on the performance of 12 volcanic ash (VA) and finely ground volcanic pumice (VP) based ASTM Type I and Type V (low C{sub 3}A) blended cement concrete mixtures with varying immersion period of up to 48 months in environments characterized by the presence of mixed magnesium-sodium sulfates. The concrete mixtures comprise a combination of two Portland cements (Type I and Type V) and four VA/VP based blended cements with two water-to-binder ratio of 0.35 and 0.45. Background experiments (in addition to strength and fresh properties) including X-ray diffraction (XRD), Differential scanning calorimetry (DSC), mercury intrusion porosimetry (MIP) and rapid chloride permeability (RCP) were conducted on all concrete mixtures to determine phase composition, pozzolanic activity, porosity and chloride ion resistance. Deterioration of concrete due to mixed sulfate attack and corrosion of reinforcing steel were evaluated by assessing concrete weight loss and measuring corrosion potentials and polarization resistance at periodic intervals throughout the immersion period of 48 months. Plain (Type I/V) cement concretes, irrespective of their C{sub 3}A content performed better in terms of deterioration and corrosion resistance compared to Type I/V VA/VP based blended cement concrete mixtures in mixed sulfate environment.

  18. Investigating the use of the Saharan dust index as a tool for the detection of volcanic ash in SEVIRI imagery

    NASA Astrophysics Data System (ADS)

    Taylor, Isabelle; Mackie, Shona; Watson, Matthew

    2015-10-01

    Despite the similar spectral signatures of ash and desert dust, relatively little has been done to explore the application of dust detection techniques to the problem of volcanic ash detection. The Saharan dust index (SDI) is routinely implemented for dust monitoring at some centres and could be utilised for volcanic ash detection with little computational expense, thereby providing a product that forecasters already have some familiarity with to complement the suite of existing ash detection tools. We illustrate one way in which the index could be implemented for the purpose of ash detection by applying it to three scenes containing volcanic ash from the 2010 Eyjafjallajökull eruption, Iceland and the 2011 eruption of Puyehue, Chile. It was also applied to an image acquired over Etna in January 2011, where a volcanic plume is clearly visible but is unlikely to contain any ash. These examples demonstrate the potential of the SDI as a tool for ash monitoring under different environmental and atmospheric conditions. In addition to presenting a valuable qualitative product to aid monitoring, this work includes a quantitative assessment of the detection skill using a manually constructed expert ash mask. The optimum implementation of any technique is likely to be dependent on both atmospheric conditions and on the properties of the imaged ash (which is often unknown in a real-time situation). Here we take advantage of access to a 'truth' rarely available in a real-time situation and calculate an ash mask based on the optimum threshold for the specific scene, which is then used to demonstrate the potential of the SDI. The SDI mask is compared to masks calculated from a simplistic implementation of the more traditional split window method, again exploiting our access to the 'truth' to set the most appropriate threshold for each scene, and to a probabilistic method that is implemented without reference to the 'truth' and which provides useful insights into the likely

  19. Evaluation of blends tincal waste, volcanic tuff, bentonite and fly ash for use as a cement admixture.

    PubMed

    Abali, Y; Bayca, S U; Targan, S

    2006-04-17

    The evaluation of blends tincal waste (TW), fly ash (FA), bentonite (BE), volcanic tuff (VT) for use as a cement admixture was investigated. The properties examined include setting time, expansion, water requirement, specific surface and compressive strength of cement mixtures. The results revealed that the early compressive strength decrease with increasing tincal waste, due to tincal waste increasing initial setting time of the cement. The tincal waste and volcanic tuff of cement mixtures increased and there was reduction in compressive strength. The more the tincal waste increased the greater retardation there was initial setting time this may be attributed to containing high amount B2O3 and MgO content. The tincal waste and fly ash increased with expansion increased. Water requirement increased as the Blaine fineness of the cement mixtures increased. The results obtained were compared with standards and five batches were advised as suitable for the standard. PMID:16314042

  20. Requirements and Implementation Feasibility for a CubeSat Thermal Infrared Imaging System to Monitor the Structure of Volcanic Ash Clouds

    NASA Astrophysics Data System (ADS)

    Thorsen, D.; Carroll, R.; Webley, P.; Hawkins, J.

    2014-12-01

    The 2010 eruption of the Eyjafjallajökull volcano in Iceland caused the cancellation of approximately 108,000 flights over an 8-day period, disrupted air traffic worldwide, and cost the airline industry more than $400 million per day. The inconvenience and economic impact of this and similar events, such as Puyehue-Cordon-Caulle in 2011, have heightened the interest in developing improved satellite remote sensing techniques for monitoring volcanic plumes and drifting clouds. For aviation safety, the operational/research community has started to move towards classifying the concentrations within volcanic plumes and clouds. Additionally, volcanic ash transport and dispersion (VATD) models are often used for forecasting ash cloud locations and they require knowledge of the structure of the erupting column to improve their ash simulations and also downwind 3-D maps of the ash cloud to calibrate/validate their modeling output. Existing remote sensing satellites utilize a brightness temperature method with thermal infrared (TIR) measurements from 10 - 12 μm to determine mass loading of volcanic ash along a single line of sight, but they have infrequent revisit times and they cannot resolve the three-dimensional structure of the ash clouds. A cluster of CubeSats dedicated to the monitoring of volcanic ash and plumes could provide both more frequent updates and the multi-aspect images needed to resolve the density structure of volcanic ash clouds and plumes. In this presentation, we discuss the feasibility and requirements for a CubeSat TIR imaging system and the associated on-board image processing that would be required to monitor the structure of volcanic ash clouds from Low Earth Orbit.

  1. Examining the influence of meteorological simulations forced by different initial and boundary conditions in volcanic ash dispersion modelling

    NASA Astrophysics Data System (ADS)

    Mulena, Gabriela C.; Allende, David G.; Puliafito, Salvador E.; Lakkis, Susan G.; Cremades, Pablo G.; Ulke, Ana G.

    2016-07-01

    The performance of the combination of the FALL3D ash dispersion model with the Weather Research and Forecast (WRF) meteorological model in the southern cone of South America under two initial and boundary conditions was evaluated. ERA-Interim and NCEP-GFS datasets were used as dynamic conditions by WRF to simulate meteorological fields for FALL3D. As a study case, we used the eruption of the Puyehue-Cordón Caulle Volcanic Complex occurred in Chile in June 2011. The simulated meteorological results were compared with the horizontal wind direction, meridional and zonal wind components, air and dew point temperatures of 7 radio sounding stations using a set of error indicators. In addition, the ash mass load simulated by FALL3D for a day of maximum dispersion of volcanic ash was evaluated using the Moderate Resolution Imaging Spectroradiometer (MODIS) data, on which the Prata algorithm was applied. As well as this, the WRF-dominant physical processes with both dynamic conditions were analyzed for that same date. Meteorological results indicated that the simulation performed with WRF and NCEP-GFS shows the lowest errors at levels between 925 and 300 hPa. Ash dispersion simulated with FALL3D and WRF in both dynamic conditions shows a different perfomance, which from the synoptic and dynamic viewpoint can be explained for the result of wind intensity and geopotential height. Moreover, WRF intiliazed with NCEP-GFS and FALL3D has a higher degree of concordance with the MODIS image. Based on the analysis and results, it was concluded that for the southern cone of South America, 1) it was not trivial for the simulation of volcanic ash dispersion to use one dynamic condition or another in WRF; 2) in that sense, meteorological variables that influenced the differences in volcanic ash dispersion were horizontal wind intensity and direction and geopotential heights; 3) the system generated from the combination of the WRF model initialized with NCEP-GFS and the FALL3D dispersion

  2. ASHEE: a compressible, Equilibrium-Eulerian model for volcanic ash plumes

    NASA Astrophysics Data System (ADS)

    Cerminara, M.; Esposti Ongaro, T.; Berselli, L. C.

    2015-10-01

    A new fluid-dynamic model is developed to numerically simulate the non-equilibrium dynamics of polydisperse gas-particle mixtures forming volcanic plumes. Starting from the three-dimensional N-phase Eulerian transport equations (Neri et al., 2003) for a mixture of gases and solid dispersed particles, we adopt an asymptotic expansion strategy to derive a compressible version of the first-order non-equilibrium model (Ferry and Balachandar, 2001), valid for low concentration regimes (particle volume fraction less than 10-3) and particles Stokes number (St, i.e., the ratio between their relaxation time and flow characteristic time) not exceeding about 0.2. The new model, which is called ASHEE (ASH Equilibrium Eulerian), is significantly faster than the N-phase Eulerian model while retaining the capability to describe gas-particle non-equilibrium effects. Direct numerical simulation accurately reproduce the dynamics of isotropic, compressible turbulence in subsonic regime. For gas-particle mixtures, it describes the main features of density fluctuations and the preferential concentration and clustering of particles by turbulence, thus verifying the model reliability and suitability for the numerical simulation of high-Reynolds number and high-temperature regimes in presence of a dispersed phase. On the other hand, Large-Eddy Numerical Simulations of forced plumes are able to reproduce their observed averaged and instantaneous flow properties. In particular, the self-similar Gaussian radial profile and the development of large-scale coherent structures are reproduced, including the rate of turbulent mixing and entrainment of atmospheric air. Application to the Large-Eddy Simulation of the injection of the eruptive mixture in a stratified atmosphere describes some of important features of turbulent volcanic plumes, including air entrainment, buoyancy reversal, and maximum plume height. For very fine particles (St → 0, when non-equilibrium effects are negligible) the

  3. ASHEE-1.0: a compressible, equilibrium-Eulerian model for volcanic ash plumes

    NASA Astrophysics Data System (ADS)

    Cerminara, M.; Esposti Ongaro, T.; Berselli, L. C.

    2016-02-01

    A new fluid-dynamic model is developed to numerically simulate the non-equilibrium dynamics of polydisperse gas-particle mixtures forming volcanic plumes. Starting from the three-dimensional N-phase Eulerian transport equations for a mixture of gases and solid dispersed particles, we adopt an asymptotic expansion strategy to derive a compressible version of the first-order non-equilibrium model, valid for low-concentration regimes (particle volume fraction less than 10-3) and particle Stokes number (St - i.e., the ratio between relaxation time and flow characteristic time) not exceeding about 0.2. The new model, which is called ASHEE (ASH Equilibrium Eulerian), is significantly faster than the N-phase Eulerian model while retaining the capability to describe gas-particle non-equilibrium effects. Direct Numerical Simulation accurately reproduces the dynamics of isotropic, compressible turbulence in subsonic regimes. For gas-particle mixtures, it describes the main features of density fluctuations and the preferential concentration and clustering of particles by turbulence, thus verifying the model reliability and suitability for the numerical simulation of high-Reynolds number and high-temperature regimes in the presence of a dispersed phase. On the other hand, Large-Eddy Numerical Simulations of forced plumes are able to reproduce the averaged and instantaneous flow properties. In particular, the self-similar Gaussian radial profile and the development of large-scale coherent structures are reproduced, including the rate of turbulent mixing and entrainment of atmospheric air. Application to the Large-Eddy Simulation of the injection of the eruptive mixture in a stratified atmosphere describes some of the important features of turbulent volcanic plumes, including air entrainment, buoyancy reversal and maximum plume height. For very fine particles (St → 0, when non-equilibrium effects are negligible) the model reduces to the so-called dusty-gas model. However

  4. Paleocene and Early Eocene volcanic ash layers in the Schlieren Flysch, Switzerland: U-Pb dating and Hf-isotopes of zircons, pumice geochemistry and origin

    NASA Astrophysics Data System (ADS)

    Koch, Simone; Winkler, Wilfried; Von Quadt, Albrecht; Ulmer, Peter

    2015-11-01

    Thin mm to cm thick bentonite layers of Paleocene to Early Eocene age in the Tonsteinschichten of the Schlieren Flysch represent volcanic ash layers. Heavy mineral analysis of the layers indicates basic to acidic volcanic sources. U/Pb dating of single zircon crystals of a Paleocene layer (WW1948) by LA-ICP-MS points to an eruption at 59.87 ± 0.41 Ma, whereas ID-TIMS shows an eruption age of 60.96 ± 0.07 Ma. Taking into account the external precision of LA-ICP-MS analyses of 1-2% both ages are overlapping and indicate an apparent minimal durations of zircon crystallization of 350 ka. Hf-isotope analysis of the same zircon crystals reveals the hybrid character of the source magma. The geochemical composition of the pumice grains of all bentonite layers is strongly affected by alteration. Nevertheless, the original character of the volcanic source can be evaluated. The Paleocene ashes (Lower Tonsteinschichten, LT) show a more fractionated multi-element pattern than the ashes of Early Eocene (Upper Tonsteinschichten, UT). The LT ash series are of rhyodacite to dacite character whereas the UT ashes fall in the field of alkali basalts. Both ash series seem to originate from a within-plate volcanic setting according to their trace element concentrations. Geochemical and temporary counterparts can be found in ash layers from Anthering (Austria) and the Danish Basin. As proposed for those ashes, volcanism connected to the opening of the North Atlantic might be the source as well for the ashes in the Schlieren Flysch. By comparison of the composition of rocks from the British Paleogene Igneous Province BPIP and the Schlieren Flysch ashes many correlations can be drawn which supports the suggestion of a North Atlantic origin of the Alpine ashes.

  5. Chemical signature of two Permian volcanic ash deposits within a bentonite bed from Melo, Uruguay.

    PubMed

    Calarge, Liane M; Meunier, Alain; Lanson, Bruno; Formoso, Milton L L

    2006-09-01

    A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m) overlying a pink massive clay deposit (0.50-2.10 m). The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively. The smectite is remarkably homogeneous throughout the profile: it is a complex mixed layer composed of three layer types whose expandability with ethylene glycol (2EG 1EG or 0EG sheets in the interlayer zone which correspond to low-, medium- and high-charge layers respectively) varies with the cation saturating the interlayer zone. The smectite homogeneity through the profile is the signature of an early alteration process in a lagoonal water which was over saturated with respect to calcite. Compaction during burial has made the bentonite bed a K-depleted closed system in which diagenetic illitization was inhibited. Variations in major, REE and minor element abundances throughout the massive clay deposit suggest that it originated from two successive ash falls. The incompatible element abundances are consistent with that of a volcanic glass fractionated from a rhyolite magma formed in a subduction/collision geological context. PMID:16936941

  6. Chemical signature of two Permian volcanic ash deposits within a bentonite bed from Melo, Uruguay.

    PubMed

    Calarge, Liane M; Meunier, Alain; Lanson, Bruno; Formoso, Milton L L

    2006-09-01

    A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m) overlying a pink massive clay deposit (0.50-2.10 m). The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively. The smectite is remarkably homogeneous throughout the profile: it is a complex mixed layer composed of three layer types whose expandability with ethylene glycol (2EG 1EG or 0EG sheets in the interlayer zone which correspond to low-, medium- and high-charge layers respectively) varies with the cation saturating the interlayer zone. The smectite homogeneity through the profile is the signature of an early alteration process in a lagoonal water which was over saturated with respect to calcite. Compaction during burial has made the bentonite bed a K-depleted closed system in which diagenetic illitization was inhibited. Variations in major, REE and minor element abundances throughout the massive clay deposit suggest that it originated from two successive ash falls. The incompatible element abundances are consistent with that of a volcanic glass fractionated from a rhyolite magma formed in a subduction/collision geological context.

  7. Imaginary refractive index and other microphysical properties of volcanic ash, Sarahan dust, and other mineral aerosols

    NASA Astrophysics Data System (ADS)

    Rocha Lima, A.; Martins, J.; Krotkov, N. A.; Artaxo, P.; Todd, M.; Ben Ami, Y.; Dolgos, G.; Espinosa, R.

    2013-12-01

    Aerosol properties are essential to support remote sensing measurements, atmospheric circulation and climate models. This research aims to improve the understanding of the optical and microphysical properties of different types of aerosols particles. Samples of volcanic ash, Saharan dust and other mineral aerosols particles were analyzed by different techniques. Ground samples were sieved down to 45um, de-agglomerated and resuspended in the laboratory using a Fluidized Bed Aerosol Generator (FBAG). Particles were collected on Nuclepore filters into PM10, PM2.5, or PM1.0. and analyzed by different techniques, such as Scanning Electron Microscopy (SEM) for determination of size distribution and shape, spectral reflectance for determination of the optical absorption properties as a function of the wavelength, material density, and X-Ray fluorescence for the elemental composition. The spectral imaginary part of refractive index from the UV to the short wave infrared (SWIR) wavelength was derived empirically from the measurements of the spectral mass absorption coefficient, size distribution and density of the material. Some selected samples were also analyzed with the Polarized Imaging Nephelometer (PI-Neph) instrument for the characterization of the aerosol polarized phase function. This work compares results of the spectral refractive index of different materials obtained by our methodology with those available in the literature. In some cases there are significant differences both in magnitude and spectral dependence of the imaginary refractive index. These differences are evaluated and discussed in this work.

  8. Particle size distributions and the sequential fragmentation/transport theory applied to volcanic ash

    SciTech Connect

    Wohletz, K.H. ); Sheridan, M.F. ); Brown, W.K. )

    1989-11-10

    The assumption that distributions of mass versus size interval for fragmented materials fit the log normal distribution is empirically based and has historical roots in the late 19th century. Other often used distributions (e.g., Rosin-Rammler, Weibull) are also empirical and have the general form for mass per size interval: {ital n}({ital l})={ital kl}{sup {alpha}} exp(-{ital l}{beta}), where {ital n}({ital l}) represents the number of particles of diameter {ital l}, {ital l} is the normalized particle diameter, and {ital k}, {alpha}, and {beta} are constants. We describe and extend the sequential fragmentation distribution to include transport effects upon observed volcanic ash size distributions. The sequential fragmentation/transport (SFT) distribution is also of the above mathematical form, but it has a physical basis rather than empirical. The SFT model applies to a particle-mass distribution formed by a sequence of fragmentation (comminution) and transport (size sorting) events acting upon an initial mass {ital m}{prime}: {ital n}({ital x}, {ital m})={ital C} {integral}{integral} {ital n}({ital x}{prime}, {ital m}{prime}){ital p}({xi}) {ital dx}{prime} {ital dm}{prime}, where {ital x}{prime} denotes spatial location along a linear axis, {ital C} is a constant, and integration is performed over distance from an origin to the sample location and mass limits from 0 to {ital m}.

  9. The 2010 Eyjafjallajökull volcanic summit eruption: evidences from ash-leachates analysis and ground deposition fluxes

    NASA Astrophysics Data System (ADS)

    Bagnato, E.; Aiuppa, A.; Bertagnini, A.; Bonadonna, C.; Cioni, R.; Pedone, M.; Pistolesi, M.

    2012-04-01

    The Eyjafjallajökull 2010 eruption was an extraordinary event in that it led to widespread over Europe. Volcanic processes which lead to eruptions can be investigated by monitoring a variety of parameters, including the composition of ash leachates. Fine-grained tephra erupted from active vents, and transported through volcanic plumes, can adsorbs, and therefore rapidly scavenge, volatile elements such as S, halogens, and metal species in the form of soluble salts adhering to ash surfaces. Analysis of such water-soluble phases is a suitable complement for the remote sensing of volcanic gases at inaccessible volcanoes, like Eyjafjallajökull. The 2010 Eyjafjallajökull eruption developed in four main phases, whose difference in gas chemistry and products has been marked in ash-leachates data too. The recurrent ash fallout provided a unique opportunity to characterize the compositional features of ash leachates, and to identify their relation (if any) with the eruptive activity styles of the volcano. By these considerations, we report on the chemical composition of leachates of 20 volcanic ash samples deposited during the most explosive Eyjafjallajökull activities (from 14 April to 8 May) and during the lava fountaining event (on 26th March 2010). We found that ash-leachate solutions are dominated - among cations - by Na and Ca, while they display nearly equal S : Cl : F abundances (mean S/Cl and S/F molar ratios of 0.85 and 0.33, respectively), as characteristic of divergent-plate and within-plate volcanism. The strong correlations between leached Ca - F , Ca - SO4, and Na - Cl (r2 = 0.7 - 0.9), suggest that fluorite, anhydrite, and halite are the most likely soluble surface minerals formed in the plume (and therefore leached during our experiments), as also reported at many active volcanoes. Our data bring evidence for variations in S and halogens proportions, with samples from 5 - 8th May which show the highest S/Cl and lowest Cl/F ratios. By combining the

  10. A retrospective study on acute health effects due to volcanic ash exposure during the eruption of Mount Etna (Sicily) in 2002

    PubMed Central

    2013-01-01

    Background Mount Etna, located in the eastern part of Sicily (Italy), is the highest and most active volcano in Europe. During the sustained eruption that occurred in October-November 2002 huge amounts of volcanic ash fell on a densely populated area south-east of Mount Etna in Catania province. The volcanic ash fall caused extensive damage to infrastructure utilities and distress in the exposed population. This retrospective study evaluates whether or not there was an association between ash fall and acute health effects in exposed local communities. Methods We collected the number and type of visits to the emergency department (ED) for diseases that could be related to volcanic ash exposure in public hospitals of the Province of Catania between October 20 and November 7, 2002. We compared the magnitude of differences in ED visits between the ash exposure period in 2002 and the same period of the previous year 2001. Results We observed a significant increase of ED visits for acute respiratory and cardiovascular diseases, and ocular disturbances during the ash exposure time period. Conclusions There was a positive association between exposure to volcanic ash from the 2002 eruption of Mount Etna and acute health effects in the Catania residents. This study documents the need for public health preparedness and response initiatives to protect nearby populations from exposure to ash fall from future eruptions of Mount Etna. PMID:23924394

  11. Impact on aviation operations of volcanic gas and ash clouds from the 2008 eruptions of Okmok and Kasatochi, Alaska

    NASA Astrophysics Data System (ADS)

    Guffanti, M.; Schneider, D. J.; Ewert, J. W.; Targosz, S.

    2008-12-01

    The eruptions of Okmok in July 2008 and Kasatochi in August 2008 both produced sulfur dioxide clouds notable for their dispersion over the northern conterminous United States. An aircraft encounter with the Okmok volcanic cloud occurred near Kodiak Island on 15 July, and some other flights were diverted north of normal air routes, but the overall impact on aviation of the Kasatochi eruption was greater. The 7 August 2008 eruption of Kasatochi sent an impressive amount of sulfur dioxide gas into the atmosphere, about 1.5 megatons according to S. Carn (this session), an order of magnitude greater than from Okmok. Preliminary estimates of Kasatochi's erupted volume range between 0.1 and 0.25 cubic kilometers (dense rock equivalent), making it one of the largest North American eruptions in the past 25 years. As Kasatochi's cloud dispersed over the Gulf of Alaska, Canada, and the northern conterminous United States, widespread disruptions to aviation operations occurred. On 10 August 2008 the ash/gas cloud passed over the southeast coast of Alaska, resulting in flight cancellations between Anchorage and Seattle, Portland, San Francisco, Denver, Los Angeles, and Vancouver BC and the stranding of a reported 6,000 passengers. The cancellations were primarily night flights, aa the airlines were concerned that pilots would not be able to visually identify the potentially hazardous volcanic cloud. As the cloud moved over Canada and parts of the United States, the area of sulfur dioxide detected by the satellite-borne Ozone Monitoring Instrument, while in accord with dispersion modeling by the Montreal Volcanic Ash Advisory Center, was much larger than the area of ash detected by the thermal infrared brightness-temperature-differencing (BTD) remote-sensing method. Concurrently, numerous pilot reports of sulfurous odors in the cockpit and visible brownish haze at cruise altitudes (the latter as late as two weeks after the eruption) suggested that sulfur dioxide gas had been

  12. What is the role of pyroclastic density currents in volcanic ash aggregation? Perspectives from a phreatoplinian eruption deposit, New Zealand

    NASA Astrophysics Data System (ADS)

    Van Eaton, A. R.; Wilson, C. J.

    2012-12-01

    This study documents the processes and products of volcanic ash aggregation within individual phases of the 25.4 ka Oruanui super-eruption from Taupo volcano, New Zealand. Textural and stratigraphic relationships of aggregates are examined in seven of the ten erupted units, which range from relatively dry styles of eruption and deposition (fall units 2, 5) to mixed (units 6, 7, 8) and dominantly wet (unit 3). Aggregate structures and grain size distributions shift abruptly over vertical scales of cm to dm within and between eruptive units, providing diagnostic features that identify deposits emplaced as vertical fallout or pyroclastic density currents (PDCs). The six categories of ash aggregates documented here are used to infer distinct volcanic and meteorological interactions in the eruption cloud related to dispersal characteristics and mode of emplacement. Our field observations support the notion that deposits bearing matrix-supported accretionary lapilli with complex internal layering and abundant rim fragments are associated with emplacement of PDCs. However, on the basis of grain size distributions and field relationships, it is inferred that these types of ash aggregates formed their ultrafine (<10 μm ash) outer layers in the overriding fine ash cloud elutriated from PDCs, not during transport within the basal portion of ground-hugging currents. The propagation of voluminous PDCs beneath an overriding buoyant plume - whether coignimbrite or vent-derived in origin - is proposed to generate the observed, concentrically layered accretionary lapilli by producing wedge-like updrafts of convectively unstable, ash-laden air. The apparent coarsening of mean grain size with distance from source, which is observed in the aggregate-bearing fall deposits, reflects a combination of multi-level plume transport and preferential scavenging of fine ash <250 μm. Proximal fallout and melting of ice in the clouds was likely to have contributed a key source of liquid water

  13. Combination of Methods for the Fractionation, Investigation, and Analysis of Micro/Nano Particles in Volcanic Ash

    NASA Astrophysics Data System (ADS)

    Valeriy, Shkinev; Michail, Ermolin; Peter, Fedotov; Aleksander, Rudnev; Nikolay, Bulychev; Vitaliy, Linnik; Gerardo, Moreno

    2013-04-01

    Micro and nanoparticles play a very important role in environment, in biology and medicine, in various technologies. The investigation of particles is often based on the fractionation according to particle size, density and charge followed by the analysis of the separated fractions. Such studies are needed in the analysis of environmental samples (natural and waste waters, soils, sediments, ashes) to assess the soil formation processes as well as distribution, transport, and biological uptake of pollutants. Recently, the review dealing with the fractionation and investigation of particles in liquid media has been published [Anal. Bioanal. Chem., 2011, v. 400, no 6, p. 1787-1804]. The present report gives a brief overview of the state-of-the-art and describes some new methods, approaches, and devices developed in the Laboratory for Concentration Methods of Vernadsky Institute for the studies of volcanic ash samples. The ash is attributed to the volcanic activity of Cordón Caulle. Puyehue and Cordón Caulle (40°35'25″S -72°07'02″W) are two coalesced volcanic vents that form a major mountain massif in Puyehue National Park in the Andes of Ranco Province, Chile. In volcanology, this group is known under the name of Puyehue-Cordón Caulle Volcanic Complex. Four different volcanoes constitute the volcanic group or complex, the Cordillera Nevada caldera, the Pliocene Mencheca volcano, Cordón Caulle fissure vents, and the Puyehue stratovolcano. Most stratovolcanoes on the Southern Volcanic Zone of the Andes, Puyehue and Cordón Caulle are located along the intersection of traverse fault with the larger north-south Liquiñe-Ofqui Fault. A new eruption started on 04 June 2011. By 15 June a dense column of ash (9 km height) was still erupting into the air, with the ash cloud spreading across the Southern Hemisphere. Actually the volcano activity continues. The samples were collected before and after the acidic rain which occurred due to the release of sulfur gases

  14. Volcanic sintering and densification of glassy and crystalline ash: Kinetics, strength recovery and seismogenicity

    NASA Astrophysics Data System (ADS)

    Vasseur, J.; Wadsworth, F. B.; Lavallee, Y.; Hess, K.; Dingwell, D. B.

    2013-12-01

    Explosive volcanism is one of the most catastrophic material failure phenomenon. During magma ascent fragmentation produces particulate magma which, if deposited above the glass transition of the interstitial melt, will sinter viscously. In-conduit tuffisites, conduit wall breccias and ash deposited from exceptionally hot pyroclastic flows are scenarios in which sintering by viscous flow is possible. Therefore, understanding the kinetics of sintering and the characteristic timescales over which magma densifies are critical to understanding the degassing timeframe in conduits and deposits. Viscous sintering is accompanied by a recovery of material strength toward that of a pore-free magma. Understanding damage mechanisms and seismic behaviour prior to failure of sintered volcanic products are also crucial for the application of micromechanical models and material failure forecasting laws. Powdered standard glass (NIST 717a) and natural obsidians have been used to explore sintering mechanisms at ambient pressure conditions and temporal evolution of connected and isolated pore-structure. We observed that sintering under low axial stress is essentially grain-size, surface tension and melt viscosity controlled. We found that the timescale over which the bulk density and the strength approaches that of pore-free melt at a given temperature is dependent on the grain-contact surface area, which can be estimated from the particle shape, the packing type and the initial total porosity. Granulometric constraint on the starting material indicates that the fraction of finer particles controls the rate of sintering as they cluster in pore spaces between larger particles and have a higher driving force for sintering due to their higher surface energy to volume ratio. In a volcano, newly formed sintering material will then further contribute to magma-plugging of the conduit and its mechanical properties will affect magma rupture and its associated precursory signals. This

  15. Dual-wavelength light-scattering technique for selective detection of volcanic ash particles in the presence of water droplets

    NASA Astrophysics Data System (ADS)

    Jurányi, Z.; Burtscher, H.; Loepfe, M.; Nenkov, M.; Weingartner, E.

    2015-12-01

    A new method is presented in this paper which analyses the scattered light of individual aerosol particles simultaneously at two different wavelengths in order to retrieve information on the particle type. We show that dust-like particles, such as volcanic ash, can be unambiguously discriminated from water droplets on a single-particle level. As a future application of this method, the detection of volcanic ash particles should be possible in a humid atmosphere in the presence of cloud droplets. The characteristic behaviour of pure water's refractive index can be used to separate water droplets and dust-like particles which are commonly found in the micrometre size range in the ambient air. The low real part of the water's refractive index around 2700-2800 nm results in low scattered light intensities compared to e.g. the visible wavelength range, and this feature can be used for the desired particle identification. The two-wavelength measurement set-up was theoretically and experimentally tested and studied. Theoretical calculations were done using Mie theory. Comparing the ratio of the scattered light at the two wavelengths (visible-to-IR (infrared), R value) for water droplets and different dust types (basalt, andesite, African mineral dust, sand, volcanic ash, pumice) showed at least 9-times-higher values (on average 70 times) for water droplets than for the dust types at any diameter within the particle size range of 2-20 μm. The envisaged measurement set-up was built up into a laboratory prototype and was tested with different types of aerosols. We generated aerosols from the following powders, simulating dust-like particles: cement dust, ISO 12103-1 A1 Ultrafine Test Dust and ash from the 2012 eruption of the Etna volcano. Our measurements verified the theoretical considerations; the median experimental R value is 8-21 times higher for water than for the "dust" particles.

  16. Emergency hospital visits in association with volcanic ash, dust storms and other sources of ambient particles: a time-series study in Reykjavík, Iceland.

    PubMed

    Carlsen, Hanne Krage; Gislason, Thorarinn; Forsberg, Bertil; Meister, Kadri; Thorsteinsson, Throstur; Jóhannsson, Thorsteinn; Finnbjornsdottir, Ragnhildur; Oudin, Anna

    2015-04-13

    Volcanic ash contributed significantly to particulate matter (PM) in Iceland following the eruptions in Eyjafjallajökull 2010 and Grímsvötn 2011. This study aimed to investigate the association between different PM sources and emergency hospital visits for cardiorespiratory causes from 2007 to 2012. Indicators of PM10 sources; "volcanic ash", "dust storms", or "other sources" (traffic, fireworks, and re-suspension) on days when PM10 exceeded the daily air quality guideline value of 50 µg/m3 were entered into generalized additive models, adjusted for weather, time trend and co-pollutants. The average number of daily emergency hospital visits was 10.5. PM10 exceeded the air quality guideline value 115 out of 2191 days; 20 days due to volcanic ash, 14 due to dust storms (two days had both dust storm and ash contribution) and 83 due to other sources. High PM10 levels from volcanic ash tended to be significantly associated with the emergency hospital visits; estimates ranged from 4.8% (95% Confidence Interval (CI): 0.6, 9.2%) per day of exposure in unadjusted models to 7.3% (95% CI: -0.4, 15.5%) in adjusted models. Dust storms were not consistently associated with daily emergency hospital visits and other sources tended to show a negative association. We found some evidence indicating that volcanic ash particles were more harmful than particles from other sources, but the results were inconclusive and should be interpreted with caution.

  17. Emergency hospital visits in association with volcanic ash, dust storms and other sources of ambient particles: a time-series study in Reykjavík, Iceland.

    PubMed

    Carlsen, Hanne Krage; Gislason, Thorarinn; Forsberg, Bertil; Meister, Kadri; Thorsteinsson, Throstur; Jóhannsson, Thorsteinn; Finnbjornsdottir, Ragnhildur; Oudin, Anna

    2015-04-01

    Volcanic ash contributed significantly to particulate matter (PM) in Iceland following the eruptions in Eyjafjallajökull 2010 and Grímsvötn 2011. This study aimed to investigate the association between different PM sources and emergency hospital visits for cardiorespiratory causes from 2007 to 2012. Indicators of PM10 sources; "volcanic ash", "dust storms", or "other sources" (traffic, fireworks, and re-suspension) on days when PM10 exceeded the daily air quality guideline value of 50 µg/m3 were entered into generalized additive models, adjusted for weather, time trend and co-pollutants. The average number of daily emergency hospital visits was 10.5. PM10 exceeded the air quality guideline value 115 out of 2191 days; 20 days due to volcanic ash, 14 due to dust storms (two days had both dust storm and ash contribution) and 83 due to other sources. High PM10 levels from volcanic ash tended to be significantly associated with the emergency hospital visits; estimates ranged from 4.8% (95% Confidence Interval (CI): 0.6, 9.2%) per day of exposure in unadjusted models to 7.3% (95% CI: -0.4, 15.5%) in adjusted models. Dust storms were not consistently associated with daily emergency hospital visits and other sources tended to show a negative association. We found some evidence indicating that volcanic ash particles were more harmful than particles from other sources, but the results were inconclusive and should be interpreted with caution. PMID:25872017

  18. Lateral Dispersion of Volcanic Ash From the Flanks of an Actively Erupting Submarine Volcano

    NASA Astrophysics Data System (ADS)

    Walker, S. L.; Baker, E. T.; Resing, J. A.; Lebon, G. T.; Lupton, J. E.; Greene, R. R.

    2006-12-01

    NW Rota-1 is an actively erupting submarine volcano along the Mariana Arc, rising some 2500 m from the local seafloor. Eruptions at Brimstone Pit, located about 30 m below the summit on the south side of the volcano at 550 m water depth, have been directly observed since 2004. Water column surveys (using CTD-O vertical cast and tow methods) in 2003, 2004 and 2006 mapped the distribution of both persistent and variable particle plumes over the summit and down the flanks. In all years, there was a non-buoyant laterally dispersing plume over the summit that was optically intense and very thin (25-30 m plume maximum), measurable up to 2-3 km from the summit. The plume was most intense in 2003 and 2004 with dNTU values reaching 5 (the upper limit of the optical backscatter sensor). High concentrations of particulate sulfur in the plume contribute to these unusually intense optical signals, as sulfur particles are efficient optical backscatters. The plume maxima depth has steadily declined over 3 years: 460 m in 2003, 485 m in 2004, and 505-530 m in 2006. In 2003, both hydrothermal and volcanic components were detected in the plume, so it is not certain that the 2003 data represent pre-eruption conditions. Deeper layers of turbidity were absent in 2003, but were observed in multiple layers surrounding the volcano in 2004 and 2006 from depths of about 700 m extending to >2500 m, and were detectable at distances up to 18 km from the summit. Microscopy and chemical analysis indicates that the particles in these layers are overwhelmingly glass fragments rather than hydrothermal precipitates. Over the scale of 3-6 days, repeat tows showed significant decreases in particle concentrations, implying some of the particles settled rapidly from these plumes. The most likely source of these layers is gravity flow of volcanic ash down the flanks, fed by violent eruptions at the summit. Detachment from the seafloor may be controlled by turbulence from current flow or internal waves

  19. Spectrally Enhanced Cloud Objects—A generalized framework for automated detection of volcanic ash and dust clouds using passive satellite measurements: 1. Multispectral analysis

    NASA Astrophysics Data System (ADS)

    Pavolonis, Michael J.; Sieglaff, Justin; Cintineo, John

    2015-08-01

    While satellites are a proven resource for detecting and tracking volcanic ash and dust clouds, existing algorithms for automatically detecting volcanic ash and dust either exhibit poor overall skill or can only be applied to a limited number of sensors and/or geographic regions. As such, existing techniques are not optimized for use in real-time applications like volcanic eruption alerting and data assimilation. In an effort to significantly improve upon existing capabilities, the Spectrally Enhanced Cloud Objects (SECO) algorithm was developed. The SECO algorithm utilizes a combination of radiative transfer theory, a statistical model, and image processing techniques to identify volcanic ash and dust clouds in satellite imagery with a very low false alarm rate. This fully automated technique is globally applicable (day and night) and can be adapted to a wide range of low earth orbit and geostationary satellite sensors or even combinations of satellite sensors. The SECO algorithm consists of four primary components: conversion of satellite measurements into robust spectral metrics, application of a Bayesian method to estimate the probability that a given satellite pixel contains volcanic ash and/or dust, construction of cloud objects, and the selection of cloud objects deemed to have the physical attributes consistent with volcanic ash and/or dust clouds. The first two components of the SECO algorithm are described in this paper, while the final two components are described in a companion paper.

  20. Rising from the ashes: Changes in salmonid fish assemblages after 30 months of the Puyehue-Cordon Caulle volcanic eruption.

    PubMed

    Lallement, Mailén; Macchi, Patricio J; Vigliano, Pablo; Juarez, Santiago; Rechencq, Magalí; Baker, Matthew; Bouwes, Nicolaas; Crowl, Todd

    2016-01-15

    Events such as volcanic eruptions may act as disturbance agents modifying the landscape spatial diversity and increasing environmental instability. On June 4, 2011 the Puyehue-Cordon Caulle volcanic complex located on Chile (2236 m.a.s.l., 40° 02' 24" S- 70° 14' 26" W) experience a rift zone eruption ejecting during the first day 950 million metric tons into the atmosphere. Due to the westerly winds predominance, ash fell differentially upon 24 million ha of Patagonia Argentinean, been thicker deposits accumulated towards the West. In order to analyze changes on stream fish assemblages we studied seven streams 8, 19 and 30 months after the eruption along the ash deposition gradient, and compare those data to pre eruption ones. Habitat features and structure of the benthic macroinvertebrate food base of fish was studied. After the eruption, substantial environmental changes were observed in association with the large amount of ash fallout. In western sites, habitat loss due to ash accumulation, changes in the riparian zone and morphology of the main channels were observed. Turbidity was the water quality variable which reflected the most changes throughout time, with NTU values decreasing sharply from West to East sites. In west sites, increased Chironomid densities were recorded 8 months after the initial eruption as well as low EPT index values. These relationships were reversed in the less affected streams farther away from the volcano. Fish assemblages were greatly influenced both by habitat and macroinvertebrate changes. The eruption brought about an initial sharp decline in fish densities and the almost total loss of young of the year in the most western streams affecting recruitment. This effect diminished rapidly with distance from the emission center. Thirty months after the eruption, environmental changes are still occurring as a consequence of basin wide ash remobilization and transport.

  1. Rising from the ashes: Changes in salmonid fish assemblages after 30 months of the Puyehue-Cordon Caulle volcanic eruption.

    PubMed

    Lallement, Mailén; Macchi, Patricio J; Vigliano, Pablo; Juarez, Santiago; Rechencq, Magalí; Baker, Matthew; Bouwes, Nicolaas; Crowl, Todd

    2016-01-15

    Events such as volcanic eruptions may act as disturbance agents modifying the landscape spatial diversity and increasing environmental instability. On June 4, 2011 the Puyehue-Cordon Caulle volcanic complex located on Chile (2236 m.a.s.l., 40° 02' 24" S- 70° 14' 26" W) experience a rift zone eruption ejecting during the first day 950 million metric tons into the atmosphere. Due to the westerly winds predominance, ash fell differentially upon 24 million ha of Patagonia Argentinean, been thicker deposits accumulated towards the West. In order to analyze changes on stream fish assemblages we studied seven streams 8, 19 and 30 months after the eruption along the ash deposition gradient, and compare those data to pre eruption ones. Habitat features and structure of the benthic macroinvertebrate food base of fish was studied. After the eruption, substantial environmental changes were observed in association with the large amount of ash fallout. In western sites, habitat loss due to ash accumulation, changes in the riparian zone and morphology of the main channels were observed. Turbidity was the water quality variable which reflected the most changes throughout time, with NTU values decreasing sharply from West to East sites. In west sites, increased Chironomid densities were recorded 8 months after the initial eruption as well as low EPT index values. These relationships were reversed in the less affected streams farther away from the volcano. Fish assemblages were greatly influenced both by habitat and macroinvertebrate changes. The eruption brought about an initial sharp decline in fish densities and the almost total loss of young of the year in the most western streams affecting recruitment. This effect diminished rapidly with distance from the emission center. Thirty months after the eruption, environmental changes are still occurring as a consequence of basin wide ash remobilization and transport. PMID:26473706

  2. Characteristics of zircons from volcanic ash-derived tonsteins in Late Permian coal fields of eastern Yunnan, China

    USGS Publications Warehouse

    Zhou, Y.; Ren, Y.; Tang, D.; Bohor, B.

    1994-01-01

    Kaolinitic tonsteins of altered synsedimentary volcanic ash-fall origin are well developed in the Late Permian coal-bearing formations of eastern Yunnan Province. Because of their unique origin, wide lateral extent, relatively constant thickness and sharp contacts with enclosing strata, great importance has been attached to these isochronous petrographic markers. In order to compare tonsteins with co-existing, non-cineritic claystones and characterize the individuality of tonsteins from different horizons for coal bed correlation, a semi-quantitative method was developed that is based on statistical analyses of the concentration and morphology of zircons and their spatial distribution patterns. This zircon-based analytical method also serves as a means for reconstructing volcanic ash-fall dispersal patterns. The results demonstrate that zircons from claystones of two different origins (i.e., tonstein and non-cineritic claystone) differ greatly in their relative abundances, crystal morphologies and spatial distribution patterns. Tonsteins from the same area but from different horizons are characterized by their own unique statistical patterns in terms of zircon concentration values and morphologic parameters (crystal length, width and the ratio of these values), thus facilitating stratigraphic correlation. Zircons from the same tonstein horizon also show continuous variation in these statistical patterns as a function of areal distribution, making it possible to identify the main path and direction in which the volcanic source materials were transported by prevailing winds. ?? 1994.

  3. Surface reactivity of volcanic ash from the eruption of Soufrière Hills volcano, Montserrat, West Indies with implications for health hazards.

    PubMed

    Horwell, Claire J; Fenoglio, Ivana; Vala Ragnarsdottir, K; Sparks, R Steve J; Fubini, Bice

    2003-10-01

    The fine-grained character of volcanic ash generated in the long-lived eruption of the Soufrière Hills volcano, Montserrat, West Indies, raises the issue of its possible health hazards. Surface- and free-radical production has been closely linked to bioreactivity of dusts within the lung. In this study, electron paramagnetic resonance (EPR) techniques have been used, for the first time, on volcanic ash to measure the production of radicals from the surface of particles. Results show that concentrations of hydroxyl radicals (HO*) in respirable ash are two to three times higher than a toxic quartz standard. The dome-collapse ash contains cristobalite, a crystalline silica polymorph that may cause adverse health effects. EPR experiments indicate, however, that cristobalite in the ash does not contribute to HO* generation. Our results show that the main cause of reactivity is removable divalent iron (Fe2+), which is present in abundance on the surfaces of the particles and is very reactive in the lung. Our analyses show that fresh ash generates more HO* than weathered ash (which has undergone progressive oxidation and leaching of iron from exposed surfaces), an effect replicated experimentally by incubating fresh ash in dilute acid. HO* production experiments also indicate that iron-rich silicate minerals are responsible for surface reactivity in the Soufrière Hills ash.

  4. Volcanic ash leaching as a means of tracing the environmental impact of the 2011 Grímsvötn eruption, Iceland.

    PubMed

    Cabré, J; Aulinas, M; Rejas, M; Fernandez-Turiel, J L

    2016-07-01

    The Grímsvötn volcanic eruption, from 21 to 28 May, 2011, was the largest eruption of the Grímsvötn Volcanic System since 1873, with a Volcanic Explosivity Index (VEI) of magnitude 4. The main geochemical features of the potential environmental impact of the volcanic ash-water interaction were determined using two different leaching methods as proxies (batch and vertical flow-through column experiments). Ash consists of glass with minor amounts of plagioclase, clinopyroxene, diopside, olivine and iron sulphide; this latter mineral phase is very rare in juvenile ash. Ash grain morphology and size reflect the intense interaction of magma and water during eruption. Batch and column leaching tests in deionised water indicate that Na, K, Ca, Mg, Si, Cl, S and F had the highest potential geochemical fluxes to the environment. Release of various elements from volcanic ash took place immediately through dissolution of soluble salts from the ash surface. Element solubilities of Grímsvötn ash regarding bulk ash composition were <1 %. Combining the element solubilities and the total estimated mass of tephra (7.29 × 10(14) g), the total inputs of environmentally important elements were estimated to be 8.91 × 10(9) g Ca, 7.02 × 10(9) g S, 1.10 × 10(9) g Cl, 9.91 × 10(8) g Mg, 9.91 × 10(8) g Fe and 1.45 × 10(8) g P The potential environmental problems were mainly associated with the release of F (5.19 × 10(9) g).

  5. Dissolution of trace metals from lava ash: influence on the composition of rainwater in the Mount Etna volcanic area.

    PubMed

    Cimino, G; Toscano, G

    1998-01-01

    Dissolution of trace metals from lava ash of the Mount Etna volcano in aqueous suspensions is studied as a function of solution pH and aerosol mass loading. The rate of dissolution and the final concentration increase with decreasing pH. Leaching experiments are found to be consistent with the observations of these metals in rainwater of the volcanic area. Elements such as Fe and Mn are important in the aqueous oxidation of SO(2) which increases the acidity of the rainwater. Leaching of Na, Ca, K, Fe and Mg may have a buffering effect in reacting with cloud and aerosol droplets.

  6. Cristobalite in volcanic ash of the soufriere hills volcano, montserrat, british west indies

    PubMed

    Baxter; Bonadonna; Dupree; Hards; Kohn; Murphy; Nichols; Nicholson; Norton; Searl; Sparks; Vickers

    1999-02-19

    Crystalline silica (mostly cristobalite) was produced by vapor-phase crystallization and devitrification in the andesite lava dome of the Soufriere Hills volcano, Montserrat. The sub-10-micrometer fraction of ash generated by pyroclastic flows formed by lava dome collapse contains 10 to 24 weight percent crystalline silica, an enrichment of 2 to 5 relative to the magma caused by selective crushing of the groundmass. The sub-10-micrometer fraction of ash generated by explosive eruptions has much lower contents (3 to 6 percent) of crystalline silica. High levels of cristobalite in respirable ash raise concerns about adverse health effects of long-term human exposure to ash from lava dome eruptions.

  7. Properties of ash-infused hail during the Grímsvötn 2011 eruption and implications for radar detection of volcanic columns

    NASA Astrophysics Data System (ADS)

    Arason, Þórður; Þorláksdóttir, Svava B.; Sigurðsson, Geirfinnur S.; Yeo, Richard F.; Thorsteinsson, Thorsteinn

    2013-04-01

    The latest Grímsvötn volcanic eruption in Iceland lasted for a week, 21-28 May 2011, while most of the tephra was erupted in the first 24 hours. During the early hours the volcanic column rose to about 20-25 km altitude. The Grímsvötn caldera is within the Vatnajökull glacier and most of the tephra was deposited on the glacier. Fortunately, for our study of ash-infused hail deposited from the column, the surface air temperatures on the glacier were below freezing level during the first few weeks after the eruption. In early June 2011 the ash deposits around the eruption site were studied, with special focus on thick distinct intermittent layers of ash-infused hail. Close-up photographs of the in-situ hail layers were taken and hail samples collected, some were kept frozen while others were allowed to melt. Most of the hail had grain sizes between 1 and 2 mm with various visual grades of ash density, from almost clear hail to ice-glaced spherical balls of packed fine ash. Both the ash and hail grain size distributions of the samples were analyzed as well as their water content. The much larger grain size of the hail than of the ash has important implications for some effective physical properties and remote detection of ash in volcanic columns. These changes in effective grain size lead to increased precipitation of ash, and affect radar reflectivity. The influence of hail formation in volcanic columns on mass flux estimates based on radar measurements will be discussed.

  8. Heterogeneous volcanism across the Permian-Triassic Boundary in South China and implications for the Latest Permian Mass Extinction: New evidence from volcanic ash layers in the Lower Yangtze Region

    NASA Astrophysics Data System (ADS)

    Liao, Zhiwei; Hu, Wenxuan; Cao, Jian; Wang, Xiaolin; Yao, Suping; Wu, Haiguang; Wan, Ye

    2016-09-01

    Volcanism has been suggested to have occurred widely in South China across the Permian-Triassic boundary (PTB); this has important implications for understanding the cause of the Latest Permian Mass Extinction (LMPE). However, few volcanic deposits have been reported in the Lower Yangtze Region and the extent of volcanism is uncertain. Herein we report new discoveries of intensive volcanism in this region for the first time, as evidenced by multiple (n > 20) and thick (3-5 cm) claystones (volcanic ash layers, K-bentonite) found in three deep-water outcrops in Xuancheng city, southern Anhui Province. Detailed petrographic and geochemical analyses of the ash layers were conducted to understand their origin and implications for the cause of the LPME, including X-ray diffraction, scanning electronic microscopy, energy dispersive spectroscopy, and whole-rock geochemistry. The petrological and mineralogical results show that the claystones contain clastic minerals indicative of a volcanic origin, such as zircon, analcites, pentagonal dodecahedral pyrite, and micro-spherules. The whole-rock geochemical data of the claystones suggest that the source rock of the ash layers was intermediate-acidic rhyodacite. The claystones are different from previously known claystones in the Middle-Upper Yangtze regions, indicating the occurrence of chemically heterogeneous volcanism in South China at the PTB.

  9. Water Repellency Effects on Water Retention in Heat Pre-treated Volcanic Ash Soil

    NASA Astrophysics Data System (ADS)

    Chhoden, T.; Karunarathna, A.; Kawamoto, K.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Water repellency (WR) in soil is a common phenomenon after forest fires all over the world. It can induce hydrological problems such as preferential flow in soils and reduced water infiltration rate which in turn can lead to surface runoff and erosion. In this study, we examined the hydrophobicity for pre-heated volcanic ash soil samples with different temperatures between 60 and 200oC and non pre-heated samples (20oC) from a single surface soil profile down to 25 cm depth. Moreover, the pre-heated samples were used to investigate the effects of pre-heat treatment and hydrophobic severity on soil-water retention properties. We first assessed the degree of water repellency for pre-heated samples by the Water Droplet Penetration Time test and Molarity of Ethanol Droplet test and categorized the water repellency into four different classes (extremely, severely, strongly and non-WR) as proposed by Bisdom et al. (1993). The depth profiles of soil organic carbon (SOC) content for the pre-heated samples were also measured. Results showed the categorized WR classes changed depending on pre-heated temperatures and residual SOC contents. For top surface soil with 0-5cm depth, pre-heated samples at 105, 125, 150 and 175oC exhibited extremely WR, pre-heated samples at 60oC exhibited severely WR, non pre-heated samples (20oC) exhibited strongly WR, and pre-heated samples at 200oC exhibited non-WR. Moreover, the threshold value of SOC above which WR occurs was found to be around 7.4% based on the measured WR classes and SOC profiles. The water supply/drainage controlled hanging column setup equipped with a newly-developed mini tensiometer-TDR coil probe (5 cm in length and 0.5 cm in diameter) was used to measure wetting and drying processes of the soil-water retention curves (SWRCs) for the pre-heated samples. Results showed that the SWRCs on the wetting process were highly affected by the degree of water repellency. Clear water-entry pressures (hwe) were observed in the SWRCs

  10. Scale effect on the water retention curve of a volcanic ash

    NASA Astrophysics Data System (ADS)

    Damiano, Emilia; Comegna, Luca; Greco, Roberto; Guida, Andrea; Olivares, Lucio; Picarelli, Luciano

    2015-04-01

    During the last decades, a number of flowslides and debris flows triggered by intense rainfall affected a wide mountainous area surrounding the "Campania Plain" (southern Italy). The involved slopes are constituted by shallow unsaturated air-fall deposits of pyroclastic nature, which stability is guaranteed by the contribution of suction on shear strength. To reliably predict the onset of slope failure triggered by critical precipitations, is essential to understand the infiltration process and the soil suction distribution in such granular deposits. The paper presents the results of a series of investigation performed at different scales to determine the soil water retention curve (SWRC) of a volcanic ash which is an es-sential element in the analysis of the infiltration processes. The soil, a silty sand, was taken at Cervinara hillslope, 30 km East of Naples, just aside an area which had been subjected to a catastrophic flowslide. The SWRC was obtained through: - standard tests in a suction-controlled triaxial apparatus (SCTX), in a pressure plate and by the Wind technique (1968) on small natural and reconstituted soil samples (sample dimensions in the order of the 1•10-6m3) ; - infiltration tests on small-scale model slopes reconstituted in an instrumented flume (sample dimensions in the order of 5•10-3m3); - suction and water content monitoring at the automatic station installed along the Cervinara hillslope. The experimental points generally were defined by coupling suction measurements through jet-fill tensiometers and water content through TDR probes installed close each others. The obtained data sets individuate three different curves characterized by different shapes in the transition zone: at larger volume element dimensions correspond curves which exhibit steeper slopes and lower values of the water content in the transition zone. This result confirms the great role of the volume element dimensions in the de-termination of hydraulic characteristics

  11. New identification and interpreted correlation, deposition, and significance of widespread Quaternary volcanic ash in the Sacramento-San Joaquin Delta, California

    NASA Astrophysics Data System (ADS)

    Maier, K. L.; Gatti, E.; Wan, E.; Ponti, D. J.; Tinsley, J. C.; Starratt, S. W.; Hillhouse, J.; Pagenkopp, M.; Olson, H. A.; Burtt, D.; Rosa, C. M.; Holzer, T. L.

    2013-12-01

    We recently identified and correlated volcanic ash deposits buried in the Sacramento-San Joaquin Delta, California, with widespread ash in the Pacific Northwest. The Sacramento-San Joaquin Delta (herein, the Delta) contains stratigraphic records of climate change, sea level variability, and tectonic processes. It drains the interior of central and northern California, covers ~1400 km2, and is underlain by Quaternary deposits that are difficult to correlate and date. Tephrochronology provides maximal depositional ages and regional sequence stratigraphic correlations. Using Electron Microprobe analysis, we identified the Loleta (0.390 Ma), the Rockland (~0.575 Ma), and an unnamed volcanic ash (>0.78-<1.45 Ma) in ten samples from eight boreholes in the Delta drilled by the California Department of Water Resources. These tephra correlate chemostratigraphically with widespread volcanic ash found in California, Nevada, and the Pacific Northwest. Major and minor element compositions of glass shards from each tephra sample also indicate that these deposits derive from Cascade Range volcanic sources. The Rockland ash erupted from the southern Cascades near Lassen Peak, California. The Loleta ash is the distal equivalent of the Bend pumice tuff that probably originated from the Three Sisters volcanoes, Oregon. The unnamed, but chemically distinctive, ash bed also resembles Cascade -type tephra. The ash layers are identified in 27 boreholes in the northern to central Delta that we correlate using facies. Grain-size distributions and sedimentary structures are inconsistent within the tephra units and indicate variations in concentrations, deposition rates, and depositional environments. Much of the Delta tephra was transported and deposited in fluvial settings. The tephra deposits occur as three facies: 1) volcanic ash, in thick deposits containing silt- to sand-size glass shards; 2) pumice, in thick deposits of bedded and variably current-structured coarse-sand to pebble

  12. Exceptionally Long Distance Transport of Volcanic Ash: Implications for Stratigraphy, Hazards and the Sourcing of Distal Tephra Deposits

    NASA Astrophysics Data System (ADS)

    Jensen, B. J. L.; Mackay, H.; Pyne-O'Donnell, S.; Plunkett, G.; Hughes, P. D. M.; Froese, D. G.; Booth, R.

    2014-12-01

    Cryptotephras (tephra not visible to the naked eye) form the foundation of the tephrostratigraphic frameworks used in Europe to date and correlate widely distributed geologic, paleoenvironmental and archaeological records. Pyne-O'Donnell et al. (2012) established the potential for developing a similar crypto-tephrostratigraphy across eastern North America by identifying multiple tephra, including the White River Ash (east; WRAe), St. Helens We and East Lake, in a peat core located in Newfoundland. Following on from this work, several ongoing projects have examined additional peat cores from Michigan, New York State, Maine, Nova Scotia and Newfoundland to build a tephrostratigraphic framework for this region. Using the precedent set by recent research by Jensen et al.(in press) that correlated the Alaskan WRAe to the European cryptotephra AD860B, unknown tephras identified in this work were not necessarily assumed to be from "expected" source areas (e.g. the Cascades). Here we present several examples of the preservation of tephra layers with an intercontinental distribution (i.e. WRAe and Ksudach 1), from relatively small magnitude events (i.e. St. Helens layer T, Mono Crater), and the first example of a Mexican ash in the NE (Volcan Ceboruco, Jala pumice). There are several implications of the identification of these units. These far-travelled ashes: (1) highlight the need to consider "ultra" distal source volcanoes for unknown cryptotephra deposits,. (2) present an opportunity for physical volcanologists to examine why some eruptions have an exceptional distribution of ash that is not necessarily controlled by the magnitude of the event. (3) complicate the idea of using tephrostratigraphic frameworks to understand the frequency of eruptions towards aiding hazard planning and prediction (e.g. Swindles et al., 2011). (4) show that there is a real potential to link tropical and mid to high-latitude paleoenvironmental records. Jensen et al. (in press) Transatlantic

  13. Which observations are necessary to estimate ash injection in the atmosphere by volcanic plumes? The case of the Eyjafjöll 2010 eruption

    NASA Astrophysics Data System (ADS)

    Kaminski, E.; Tait, S.; Ferrucci, F.

    2010-12-01

    On the 14th april of 2010, after about a month of effusive lateral eruption, the Eyjafjallajökull volcano, Iceland, changed to a more violent sub-glacial explosive eruption. The eruption produced a powerful volcanic plume that stunned air traffic above Europe for a few weeks. During this "sub-Plinian" activity, the key issue was the necessity for volcanologists to provide robust estimates of the ash content of the plume, a parameter required to correctly estimate the dispersion of ash in the atmosphere, and the related necessity to close (or not) the airports. 1D models of convective plumes show that the classical method relating the mass flux to the plume height, provides a satisfying estimate of the ash flux and ash concentration in the plume only for Plinian eruptions in which the magma is very finely fragmented. For "intermediate" silicic and basaltic eruptions, in which both a convective plume and an effusive lava flow or pyroclastic flows are produced, the "plinian" framework yields an over-estimation of the ash content of the plume. As a consequence, a correct estimation of ash concentration in a volcanic plume required a complementary knowledge of the partitioning of the mass flux between ground and atmospheric flow. A reference abacus is provided as a tool for a real time estimate of both the ash flux and ash concentration in the volcanic plume as a function of the ground and atmospheric fluxes. In the case of the Eyjafjallajökull eruption, the use of the "Plinian" model yielded an overestimation of the ash content in the plume of a factor 2, an acceptable error due to the interaction of water that enhanced magma fragmentation. In a dry basaltic eruption, the plinian model may overestimate the ash content by more than two orders of magnitude, and a knowledge of the ground flux is essential.

  14. Possible secondary apatite fission track age standard from altered volcanic ash beds in the middle Jurassic Carmel Formation, Southwestern Utah

    USGS Publications Warehouse

    Kowallis, B.J.; Christiansen, E.H.; Everett, B.H.; Crowley, K.D.; Naeser, C.W.; Miller, D.S.; Deino, A.L.

    1993-01-01

    Secondary age standards are valuable in intra- and interlaboratory calibration. At present very few such standards are available for fission track dating that is older than Tertiary. Several altered volcanic ash beds occur in the Middle Jurassic Carmel Formation in southwestern Utah. The formation was deposited in a shallow marine/sabhka environment. Near Gunlock, Utah, eight ash beds have been identified. Sanidines from one of the ash beds (GUN-F) give a single-crystal laser-probe 40Ar/39Ar age of 166.3??0.8 Ma (2??). Apatite and zircon fission track ages range from 152-185 Ma with typically 15-20 Ma errors (2??). Track densities in zircons are high and most grains are not countable. Apatites are fairly common in most of the ash beds and have reasonable track densities ranging between 1.2-1.5 ?? 106 tracks/cm2. Track length distributions in apatites are unimodal, have standard deviations <1??m, and mean track lengths of about 14-14.5 ??m. High Cl apatites (F:Cl:OH ratio of 39:33:28) are particularly abundant and large in ash GUN-F, and are fairly easy to concentrate, but the concentrates contain some siderite, most of which can be removed by sieving. GUN-F shows evidence of some reworking and detriaal contamination based on older single grain 40Ar/39Ar analyses and some rounding of grains, but the apatite population appears to be largely uncontaminated. At present BJK has approximately 12 of apatite separate from GUN-F. ?? 1993.

  15. Validation of a continuous flow method for the determination of soluble iron in atmospheric dust and volcanic ash.

    PubMed

    Simonella, Lucio E; Gaiero, Diego M; Palomeque, Miriam E

    2014-10-01

    Iron is an essential micronutrient for phytoplankton growth and is supplied to the remote areas of the ocean mainly through atmospheric dust/ash. The amount of soluble Fe in dust/ash is a major source of uncertainty in modeling-Fe dissolution and deposition to the surface ocean. Currently in the literature, there exist almost as many different methods to estimate fractional solubility as researchers in the field, making it difficult to compare results between research groups. Also, an important constraint to evaluate Fe solubility in atmospheric dust is the limited mass of sample which is usually only available in micrograms to milligrams amounts. A continuous flow (CF) method that can be run with low mass of sediments (<10mg) was tested against a standard method which require about 1g of sediments (BCR of the European Union). For validation of the CF experiment, we run both methods using South American surface sediment and deposited volcanic ash. Both materials tested are easy eroded by wind and are representative of atmospheric dust/ash exported from this region. The uncertainty of the CF method was obtained from seven replicates of one surface sediment sample, and shows very good reproducibility. The replication was conducted on different days in a span of two years and ranged between 8 and 22% (i.e., the uncertainty for the standard method was 6-19%). Compared to other standardized methods, the CF method allows studies of dissolution kinetic of metals and consumes less reagents and time (<3h). The method validated here is suggested to be used as a standardized method for Fe solubility studies on dust/ash.

  16. Advances in Monitoring, Modelling and Forecasting Volcanic Ash Plumes over the Past 5 Years and the Impact on Preparedness from the London VAAC Perspective

    NASA Astrophysics Data System (ADS)

    Lee, D. S.; Lisk, I.

    2015-12-01

    Hosted and run by the Met Office, the London VAAC (Volcanic Ash Advisory Centre) is responsible for issuing advisories on the location and likely dispersion of ash clouds originating from volcanoes in the North East Atlantic, primarily from Iceland. These advisories and additional guidance products are used by the civil aviation community to make decisions on airspace flight management. London VAAC has specialist forecasters who use a combination of volcano source data, satellite-based, ground-based and aircraft observations, weather forecast models and dispersion models. Since the eruption of the Icelandic volcano Eyjafjallajökull in 2010, which resulted in the decision by many northern European countries to impose significant restrictions on the use of their airspace, London VAAC has been active in further developing its volcanic ash monitoring, modelling and forecasting capabilities, collaborating with research organisations, industry, other VAACs, Meteorological Services and the Volcano Observatory in Iceland. It has been necessary to advance operational capabilities to address evolving requirements, including for more quantitative assessments of volcanic ash in the atmosphere. Here we summarise advances in monitoring, modelling and forecasting of volcanic ash plumes over the past 5 years from the London VAAC perspective, and the realization of science into operations. We also highlight the importance of collaborative activities, such as the 'VAAC Best Practice' Workshop, where information is exchanged between all nine VAACs worldwide on the operational practices in monitoring and forecasting volcanic ash, with the aim of working toward a more harmonized service for decision makers in the aviation community. We conclude on an evaluation of how better we are prepared for the next significant ash-rich Icelandic eruption, and the challenges still remaining.

  17. Cristobalite in volcanic ash of the soufriere hills volcano, montserrat, british west indies

    PubMed

    Baxter; Bonadonna; Dupree; Hards; Kohn; Murphy; Nichols; Nicholson; Norton; Searl; Sparks; Vickers

    1999-02-19

    Crystalline silica (mostly cristobalite) was produced by vapor-phase crystallization and devitrification in the andesite lava dome of the Soufriere Hills volcano, Montserrat. The sub-10-micrometer fraction of ash generated by pyroclastic flows formed by lava dome collapse contains 10 to 24 weight percent crystalline silica, an enrichment of 2 to 5 relative to the magma caused by selective crushing of the groundmass. The sub-10-micrometer fraction of ash generated by explosive eruptions has much lower contents (3 to 6 percent) of crystalline silica. High levels of cristobalite in respirable ash raise concerns about adverse health effects of long-term human exposure to ash from lava dome eruptions. PMID:10024235

  18. Characterization of Eyjafjallajokull volcanic ash particles and a protocol for rapid risk assessment.

    PubMed

    Gislason, S R; Hassenkam, T; Nedel, S; Bovet, N; Eiriksdottir, E S; Alfredsson, H A; Hem, C P; Balogh, Z I; Dideriksen, K; Oskarsson, N; Sigfusson, B; Larsen, G; Stipp, S L S

    2011-05-01

    On April 14, 2010, when meltwaters from the Eyjafjallajökull glacier mixed with hot magma, an explosive eruption sent unusually fine-grained ash into the jet stream. It quickly dispersed over Europe. Previous airplane encounters with ash resulted in sandblasted windows and particles melted inside jet engines, causing them to fail. Therefore, air traffic was grounded for several days. Concerns also arose about health risks from fallout, because ash can transport acids as well as toxic compounds, such as fluoride, aluminum, and arsenic. Studies on ash are usually made on material collected far from the source, where it could have mixed with other atmospheric particles, or after exposure to water as rain or fog, which would alter surface composition. For this study, a unique set of dry ash samples was collected immediately after the explosive event and compared with fresh ash from a later, more typical eruption. Using nanotechniques, custom-designed for studying natural materials, we explored the physical and chemical nature of the ash to determine if fears about health and safety were justified and we developed a protocol that will serve for assessing risks during a future event. On single particles, we identified the composition of nanometer scale salt coatings and measured the mass of adsorbed salts with picogram resolution. The particles of explosive ash that reached Europe in the jet stream were especially sharp and abrasive over their entire size range, from submillimeter to tens of nanometers. Edges remained sharp even after a couple of weeks of abrasion in stirred water suspensions. PMID:21518890

  19. Characterization of Eyjafjallajokull volcanic ash particles and a protocol for rapid risk assessment.

    PubMed

    Gislason, S R; Hassenkam, T; Nedel, S; Bovet, N; Eiriksdottir, E S; Alfredsson, H A; Hem, C P; Balogh, Z I; Dideriksen, K; Oskarsson, N; Sigfusson, B; Larsen, G; Stipp, S L S

    2011-05-01

    On April 14, 2010, when meltwaters from the Eyjafjallajökull glacier mixed with hot magma, an explosive eruption sent unusually fine-grained ash into the jet stream. It quickly dispersed over Europe. Previous airplane encounters with ash resulted in sandblasted windows and particles melted inside jet engines, causing them to fail. Therefore, air traffic was grounded for several days. Concerns also arose about health risks from fallout, because ash can transport acids as well as toxic compounds, such as fluoride, aluminum, and arsenic. Studies on ash are usually made on material collected far from the source, where it could have mixed with other atmospheric particles, or after exposure to water as rain or fog, which would alter surface composition. For this study, a unique set of dry ash samples was collected immediately after the explosive event and compared with fresh ash from a later, more typical eruption. Using nanotechniques, custom-designed for studying natural materials, we explored the physical and chemical nature of the ash to determine if fears about health and safety were justified and we developed a protocol that will serve for assessing risks during a future event. On single particles, we identified the composition of nanometer scale salt coatings and measured the mass of adsorbed salts with picogram resolution. The particles of explosive ash that reached Europe in the jet stream were especially sharp and abrasive over their entire size range, from submillimeter to tens of nanometers. Edges remained sharp even after a couple of weeks of abrasion in stirred water suspensions.

  20. Characterization of Eyjafjallajökull volcanic ash particles and a protocol for rapid risk assessment

    PubMed Central

    Gislason, S. R.; Hassenkam, T.; Nedel, S.; Bovet, N.; Eiriksdottir, E. S.; Alfredsson, H. A.; Hem, C. P.; Balogh, Z. I.; Dideriksen, K.; Oskarsson, N.; Sigfusson, B.; Larsen, G.; Stipp, S. L. S.

    2011-01-01

    On April 14, 2010, when meltwaters from the Eyjafjallajökull glacier mixed with hot magma, an explosive eruption sent unusually fine-grained ash into the jet stream. It quickly dispersed over Europe. Previous airplane encounters with ash resulted in sandblasted windows and particles melted inside jet engines, causing them to fail. Therefore, air traffic was grounded for several days. Concerns also arose about health risks from fallout, because ash can transport acids as well as toxic compounds, such as fluoride, aluminum, and arsenic. Studies on ash are usually made on material collected far from the source, where it could have mixed with other atmospheric particles, or after exposure to water as rain or fog, which would alter surface composition. For this study, a unique set of dry ash samples was collected immediately after the explosive event and compared with fresh ash from a later, more typical eruption. Using nanotechniques, custom-designed for studying natural materials, we explored the physical and chemical nature of the ash to determine if fears about health and safety were justified and we developed a protocol that will serve for assessing risks during a future event. On single particles, we identified the composition of nanometer scale salt coatings and measured the mass of adsorbed salts with picogram resolution. The particles of explosive ash that reached Europe in the jet stream were especially sharp and abrasive over their entire size range, from submillimeter to tens of nanometers. Edges remained sharp even after a couple of weeks of abrasion in stirred water suspensions. PMID:21518890

  1. Differentiation of volcanic ash-fall and water-borne detrital layers in the Eocene Senakin coal bed, Tanjung Formation, Indonesia

    USGS Publications Warehouse

    Ruppert, L.F.; Moore, T.A.

    1993-01-01

    The Sangsang deposit of the Eocene Senakin coal bed, Tanjung Formation, southeastern Kalimantan, Indonesia, contains 11 layers, which are thin ( 70%). These layers are characterized by their pelitic macroscopic texture. Examination of eight of the layers by scanning-electron microscopy, energy-dispersive X-ray, and X-ray diffraction analyses show that they are composed primarily of fairly well-crystallized kaolinite, much of which is vermicular. Accessory minerals include abundant Ti oxide, rare-earth element-rich Ca and A1 phosphates, quartz that luminescences in the blue color range, and euhedral to subhedral pyroxene, hornblende, zircon, and sanidine. Although this mineral suite is suggestive of volcanic ash-fall material, only the four pelitic layers in the middle of the bed are thought to be solely derived from volcanic ash-falls on the basis of diagnostic minerals, replaced glass shards, and lithostratigraphic relationships observed in core and outcrop. The three uppermost pelitic layers contain octahedral chromites, some quartz grains that luminesce in teh orange color range, and some quartz grains that contain two-phase fluid inclusions. These layers are interpreted to be derived from a combination of volcanic ash-fall material and hydrologic transport of volcaniclastic sediment. In contrast, the lowermost pelitic layer, which contains large, rounded FeMg-rich chromites, is thought to have been dominantly deposited by water. The source of the volcanic ash-fall material may have been middle Tertiary volcanism related to plate tectonic activity between Kalimantan and Sulawesi. The volcanic ash was deposited in sufficient amounts to be preserved as layers within the coal only in the northern portions of the Senakin region: the southern coal beds in the region do not contain pelitic layers. ?? 1993.

  2. Volcanic ash leachate compositions and assessment of health and agricultural hazards from 2012 hydrothermal eruptions, Tongariro, New Zealand

    NASA Astrophysics Data System (ADS)

    Cronin, S. J.; Stewart, C.; Zernack, A. V.; Brenna, M.; Procter, J. N.; Pardo, N.; Christenson, B.; Wilson, T.; Stewart, R. B.; Irwin, M.

    2014-10-01

    After almost 80 years of quiescence, the upper Te Maari vent on Mt. Tongariro erupted suddenly at 2352 h (NZ time) on 6 August 2012. The short-lived hydrothermal eruption distributed a fine ash of minor volume (~ 5 × 105 m3) over 200 km from source. The threat of further eruptions prompted an investigation of the possible health and agricultural impacts of any future eruptions from this volcano, particularly since the most recent large-scale ash falls in New Zealand in 1995-1996 had generated significant agricultural problems, including livestock deaths. Deposited ash was sampled between 5 and 200 km from the volcano as soon as possible after the eruption. Two sub-lobes of ash were identified from different vent areas and displayed subtly different leaching properties. The first was an initial small lobe directed NNE, likely formed from drifting low-level clouds associated with the initial lateral explosive blast and surges. The main fall lobe, directed eastward, was sourced from a short-lived vertical plume that rose up to c. 8 km. Ash from the initial fall lobe had higher concentrations of F and Al, in single-step leaches as well as in the totals of three, sequential extractions. Further, the initial lobe showed a higher proportion of soluble F and Al extracted in the first leach, compared to totals. A linear relationship between concentrations of Al and F in single leaches from the 6 August eruption was highly significant (Pearson correlation coefficient r = 0.987 for 1:20 leaching ratios and r = 0.971 for 1:100), suggesting the presence of soluble alumino-fluoride complexes (AlFx+ 3 - x). An even more significant 1:1 ratio is displayed for the largest concentration leached ions of Ca and SO4, which correspond to the presence of crystalline gypsum throughout the newly excavated hydrothermal system. Although no fresh magma was erupted in this event, a shallow intrusion prior to the hydrothermal explosion apparently provided significant contents of volcanic gas

  3. Mineralogical and Sulfur Isotopic Study on Volcanic Ash of the 2014 Eruption at Ontake Volcano, Central Honshu, Japan

    NASA Astrophysics Data System (ADS)

    Imura, T.; Minami, Y.; Ohba, T.; Takahashi, R.; Imai, A.; Hayashi, S.

    2015-12-01

    Ontake volcano erupted on 27th September 2014. Components in fallout samples were analyzed with microscope, XRD, and SEM-EDS. Pyrophyllite, smectite, muscovite, kaoline group minerals, quartz, cristobalite, tridymite, pyrite, alunite, gypsum and anhydrite were identified from bulk samples. Coarse ash fraction (> 125 µm) consists mainly of siliceous fragments that are intensely altered and contain pyrite and rutile. Weakly-altered dark-gray volcanic rock fragments are also contained. Fine fraction is abundant in euhedral free crystals of alunite and gypsum and aggregates of silica minerals. The 34S/32S ratios of bulk ash samples were analyzed for sulfur leached by water (water-soluble sulfate), gastric (HCl-soluble sulfate), and HNO3 (sulfide). Gastric and HNO3 leaching methods were applied to coarse fraction too. The bulk δ34SCDT compositions of water-soluble sulfate, HCl-soluble sulfate and sulfide were +14.7 ‰, +15.7 ‰, and -4.7 ‰, respectively. Those of HCl-soluble sulfate and sulfide in coarse fraction were +9.1 ‰ and -4.3 ‰, respectively. Paragenesis of quartz and pyrophyllite in single grain implies hydrothermal alteration by hot (> 230 °C), acidic fluid in the sub-volcanic system. The sulfur isotope geothermometry (Ohmoto and Rye, 1979) applied to the pair of water-soluble sulfate and bulk sulfide resulted in 306 °C. Similar temperature (ca. 296 °C) was estimated for the pair of HCl-soluble sulfate and sulfide in bulk ash. The mineralogy and sulfur isotopic study indicate that the 2014 Ontake eruption was derived from an acidic high-temperature (ca. 300 °C) sub-volcanic hydrothermal fluid. However, the estimated temperature for the pair of HCl-soluble sulfate and sulfide from coarse fraction resulted in higher temperature (ca. 482 °C). The coarse fraction preserved the past temperature record of the hydrothermal fluid, because the coarse lithic fragments were derived from pre-existing altered rocks.

  4. Evidence of volcanic ash at a K-T boundary section: Ocean drilling program hole 690 C, Maud Rise, Weddell Sea off East Antarctica

    NASA Technical Reports Server (NTRS)

    Wise, S. W.; Hamilton, N.; Pospichal, J.; Barker, P. F.; Kennett, James P.; Oconnell, S.; Bryant, W. R.; Burckle, L. H.; Egeberg, P. K.; Futterer, D. K.

    1988-01-01

    Rare vitric volcanogenic ash but more abundant clay minerals considered volcanogenic in origin are associated with an expanded and essentially complete K-T boundary sequence from Ocean Drilling Project (ODP) Hole 690 C on Maud Rise in the Weddell Sea off East Antarctica. Results at this writing are preliminary and are still based to some extent on shipboard descriptions. Further shore-based studies are in progress. It would appear, however, that the presence of volcanic ash and altered ash in the Danian section beginning at the biostratigraphically and paleomagnetically determined K-T boundary on Maud Rise can be cited as evidence of significant volcanic activity within the South Atlantic-Indian Ocean sector of the Southern Ocean coincident with the time of biotic crises at the end of the Maestrichtian. This is a postulated time of tectonic and volcanic activity within this Southern Hemisphere region, including possible initiation of the Reunion hot spot and a peak in explosive volcanism on Walvis Ridge (1) among other events. A causal relationship with the biotic crisis is possible and volcanism should be given serious consideration as a testable working hypothesis to explain these extinctions.

  5. Altered volcanic ash partings in Wasatch Formation coal beds of the northern Powder River basin: composition and geologic applications

    USGS Publications Warehouse

    Bohor, Bruce Forbes; Phillips, Richard E.; Pollastro, Richard M.

    1979-01-01

    In contrast to the coal-bearing rocks of the Appalachian and Eastern Interior Basins, those of the northern Powder River Basin exhibit more complex stratigraphic and facies relationships, and regional correlations of coal beds are, therefore, more difficult to establish. Recently, however, several coal beds in the Powder River Basin, as well as coal beds in several other coal basins of the Rocky Mountain region, have been found to contain thin but persist·ent layers. of altered volcanic ash described as kaolinitic bentonites (Bohor, 1976, 1977, 1978, Bohor and others, 1976, 1978, Bohor and Pillmore, 1976). These layers serve as isochronous marker horizons which aid in correlating coal beds over broad areas.

  6. The edge of time: Dating young volcanic ash layers with the 40Ar- 39Ar laser probe

    USGS Publications Warehouse

    Chen, Y.; Smith, P.E.; Evensen, N.M.; York, D.; Lajoie, K.R.

    1996-01-01

    Argon-40-argon-39 single-crystal dating of young (5000 to 30,000 years ago) volcanic ash layers erupted from the Mono Craters, California, shows that the method can yield meaningful ages in Holocene tephra. Because of ubiquitous xenocrystic contamination, the data do not form isochrons but plot in wedge-shaped regions on an argon isotopic diagram. The upper boundary of the region is an isochron matching the 14C-derived age of the eruption. Such contamination-related patterns may be common in dating young materials by the single-crystal method. Argon dating by this method can help refine the time scale of physical and biological evolution over the past 100,000 years.

  7. Effect of long-term different fertilization on bacterial community structures and diversity in citrus orchard soil of volcanic ash.

    PubMed

    Joa, Jae Ho; Weon, Hang Yeon; Hyun, Hae Nam; Jeun, Young Chull; Koh, Sang Wook

    2014-12-01

    This study was conducted to assess bacterial species richness, diversity and community distribution according to different fertilization regimes for 16 years in citrus orchard soil of volcanic ash. Soil samples were collected and analyzed from Compost (cattle manure, 2,000 kg/10a), 1/2 NPK+compost (14-20-14+2,000 kg/10a), NPK+compost (28-40-28+2,000 kg/10a), NPK (28-40-28 kg/10a), 3 NPK (84-120-84 kg/10a), and Control (no fertilization) plot which have been managed in the same manners with compost and different amount of chemical fertilization. The range of pyrosequencing reads and OTUs were 4,687-7,330 and 1,790-3,695, respectively. Species richness estimates such as Ace, Chao1, and Shannon index were higher in 1/2 NPK+compost than other treatments, which were 15,202, 9,112, 7.7, respectively. Dominant bacterial groups at level of phylum were Proteobacteria, Acidobacteria, and Actinobacteria. Those were occupied at 70.9% in 1/2 NPK+compost. Dominant bacterial groups at level of genus were Pseudolabrys, Bradyrhizobium, and Acidobacteria. Those were distributed at 14.4% of a total of bacteria in Compost. Soil pH displayed significantly closely related to bacterial species richness estimates such as Ace, Chao1 (p<0.05) and Shannon index (p<0.01). However, it showed the negative correlation with exchangeable aluminum contents (p<0.05). In conclusion, diversity of bacterial community in citrus orchard soil was affected by fertilization management, soil pH changes and characteristics of volcanic ash. PMID:25467117

  8. Effect of long-term different fertilization on bacterial community structures and diversity in citrus orchard soil of volcanic ash.

    PubMed

    Joa, Jae Ho; Weon, Hang Yeon; Hyun, Hae Nam; Jeun, Young Chull; Koh, Sang Wook

    2014-12-01

    This study was conducted to assess bacterial species richness, diversity and community distribution according to different fertilization regimes for 16 years in citrus orchard soil of volcanic ash. Soil samples were collected and analyzed from Compost (cattle manure, 2,000 kg/10a), 1/2 NPK+compost (14-20-14+2,000 kg/10a), NPK+compost (28-40-28+2,000 kg/10a), NPK (28-40-28 kg/10a), 3 NPK (84-120-84 kg/10a), and Control (no fertilization) plot which have been managed in the same manners with compost and different amount of chemical fertilization. The range of pyrosequencing reads and OTUs were 4,687-7,330 and 1,790-3,695, respectively. Species richness estimates such as Ace, Chao1, and Shannon index were higher in 1/2 NPK+compost than other treatments, which were 15,202, 9,112, 7.7, respectively. Dominant bacterial groups at level of phylum were Proteobacteria, Acidobacteria, and Actinobacteria. Those were occupied at 70.9% in 1/2 NPK+compost. Dominant bacterial groups at level of genus were Pseudolabrys, Bradyrhizobium, and Acidobacteria. Those were distributed at 14.4% of a total of bacteria in Compost. Soil pH displayed significantly closely related to bacterial species richness estimates such as Ace, Chao1 (p<0.05) and Shannon index (p<0.01). However, it showed the negative correlation with exchangeable aluminum contents (p<0.05). In conclusion, diversity of bacterial community in citrus orchard soil was affected by fertilization management, soil pH changes and characteristics of volcanic ash.

  9. Runoff and erosion effects after prescribed fire and wildfire on volcanic ash-cap soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AFTER PRESCRIBED BURNS AT THREE LOCATIONS AND ONE WILDFIRE, RAINFALL SIMULATIONS STUDIES WERE COMPLETED TO COMPARE POSTFIRE RUNOFF RATES AND SEDIMENT YIELDS ON ASH-CAP SOIL IN CONIFER FOREST REGIONS OF NOTHERN IDAHO AND WESTERN MONTANA. THE MEASURED FIRE EFFECTS WERE DIFFERENTIATED BY BURN SEVERITY ...

  10. Emergency Hospital Visits in Association with Volcanic Ash, Dust Storms and Other Sources of Ambient Particles: A Time-Series Study in Reykjavík, Iceland

    PubMed Central

    Carlsen, Hanne Krage; Gislason, Thorarinn; Forsberg, Bertil; Meister, Kadri; Thorsteinsson, Throstur; Jóhannsson, Thorsteinn; Finnbjornsdottir, Ragnhildur; Oudin, Anna

    2015-01-01

    Volcanic ash contributed significantly to particulate matter (PM) in Iceland following the eruptions in Eyjafjallajökull 2010 and Grímsvötn 2011. This study aimed to investigate the association between different PM sources and emergency hospital visits for cardiorespiratory causes from 2007 to 2012. Indicators of PM10 sources; “volcanic ash”, “dust storms”, or “other sources” (traffic, fireworks, and re-suspension) on days when PM10 exceeded the daily air quality guideline value of 50 µg/m3 were entered into generalized additive models, adjusted for weather, time trend and co-pollutants. The average number of daily emergency hospital visits was 10.5. PM10 exceeded the air quality guideline value 115 out of 2191 days; 20 days due to volcanic ash, 14 due to dust storms (two days had both dust storm and ash contribution) and 83 due to other sources. High PM10 levels from volcanic ash tended to be significantly associated with the emergency hospital visits; estimates ranged from 4.8% (95% Confidence Interval (CI): 0.6, 9.2%) per day of exposure in unadjusted models to 7.3% (95% CI: −0.4, 15.5%) in adjusted models. Dust storms were not consistently associated with daily emergency hospital visits and other sources tended to show a negative association. We found some evidence indicating that volcanic ash particles were more harmful than particles from other sources, but the results were inconclusive and should be interpreted with caution. PMID:25872017

  11. Mineralogical analyses and in vitro screening tests for the rapid evaluation of the health hazard of volcanic ash at Rabaul volcano, Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Le Blond, Jennifer S.; Horwell, Claire J.; Baxter, Peter J.; Michnowicz, Sabina A. K.; Tomatis, Maura; Fubini, Bice; Delmelle, Pierre; Dunster, Christina; Patia, Herman

    2010-11-01

    The continuous ash and gas emissions from the Tavurvur cone in Rabaul caldera, Papua New Guinea, during 2007-08, raised concerns regarding how exposure would affect the respiratory health of nearby populations and impact on the environment. As part of a formal evaluation of the effects of volcanic emissions on public health, we investigated the potential health hazard of the ash using a suite of selected mineralogical analyses and in vitro toxicity screening tests. The trachy -andesitic ash comprised 2.1-6.7 vol.% respirable (sub -4 μm diameter) particles. The crystalline silica content was 1.9-5.0 wt.% cristobalite (in the bulk sample) with trace amounts of quartz and/or tridymite. Scanning electron microscopy showed that the ash particles were angular with sparse, fibre -like particles (˜3-60 μm max. diameter) observed in some samples, which we confirmed to be CaSO4 (gypsum, at <6 wt.% in the bulk samples) and not asbestiform fibres. The ash specific surface area was low (0.1-2.7 m2 g-1). The leached solution from one of the ash samples was slightly acidic (pH 5.6), but did not contain high levels of toxic metals (such as F, Cu, Zn, Mn, As, Ni and Cd) when compared to previously tested volcanic ash leachates. Ash samples generated potentially -harmful hydroxyl radicals through an iron -mediated catalytic reaction, in the range of 0.15-2.47 μmol m-2 (after 30 min of reaction). However, measurement of particle oxidative capacity (potential oxidative stress reaction using ascorbic acid) and silica -like injury to red blood cells (erythrolysis assay, i.e. measurement of cell death) nevertheless revealed low biological reactivity. The findings suggest that acute exposure to the ash would have a limited potential to exacerbate pre -existing conditions such as asthma or chronic bronchitis, and the potential for chronic exposure leading to silicosis was low.

  12. Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka.

    PubMed

    Lane, Christine S; Chorn, Ben T; Johnson, Thomas C

    2013-05-14

    The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, which revises the chronology of past climatic events in East Africa. The YTT in Lake Malawi is not accompanied by a major change in sediment composition or evidence for substantial temperature change, implying that the eruption did not significantly impact the climate of East Africa and was not the cause of a human genetic bottleneck at that time.

  13. The E-PROFILE network of automatic LIDARS and ceilometers for operational monitoring of cloud base, aerosols and volcanic ash

    NASA Astrophysics Data System (ADS)

    Haefele, Alexander; Martucci, Giovanni; Haffelin, Martial; Besson, Florence; Lehmann, Volker

    2014-05-01

    During the last years it has been shown that ceilometers are cost effective instruments for vertical profiling of aerosols with proven skills for volcanic plumes detection. As a reaction to the eruptions of the Icelandic volcanoes in 2010 and 2011 and upon recommendation of the COST ES0702 action EG-CLIMET, EUMETNET created the E-PROFILE activity as part of the observation programme which is supported by 18 national meteorological services. E-PROFILE is the continuation of the operational RADAR wind-profiler network E-WINPROF. The new objective of E-PROFILE is to integrate the approximately 700 ceilometers of the E-PROFILE country members into a European network providing vertical profiles for the monitoring of cloud base, aerosols and volcanic ash. A standardized calibration procedure is being developed in collaboration with the COST Action ES1303 TOPROF to provide profile information homogeneously across the network. The information will be distributed in real time and visualized on an interactive map. We present a detailed description of the activity and report on the current status of the development.

  14. Effects of quartz, airborne particulates and fly ash fractions from a waste incinerator on elastase release by activated and nonactivated rabbit alveolar macrophages

    SciTech Connect

    Gulyas, H.; Labedzka, M.; Schmidt, N.; Gercken, G.

    1988-01-01

    Elastase release from cultured, activated and nonactivated rabbit alveolar macrophages (AM) was investigated after stimulation by different environmentally related mineral dusts (50-1000 micrograms/10(6) cells). Eight different dusts were analyzed for element contents and grain size: one rural and three urban airborne dusts, a coarse and a fine fraction of a sieved waste incinerator fly ash, a sonicated coarse fly ash fraction, and the standard quartz dust DQ 12. The fine fly ash fraction, the sonicated coarse fly ash fraction, and the quartz dust DQ 12 enhanced elastase release by activated AM. Only one of the tested airborne dusts effected a comparable elastase release. The untreated coarse fraction of the fly ash did not cause a significant increase of extracellular elastase activities. Elastase release was dependent on particle numbers and chemical composition and correlated best with barium and tin contents. Nonactivated AM released higher elastase activities than activated AM at low-dose levels. The possible role of dust-induced elastase secretion in the pathogenesis of emphysema is discussed.

  15. Estimation of volcanic ash emissions with satellite data: The inclusion of mass loading and plume height information in modified 4D-Var

    NASA Astrophysics Data System (ADS)

    Lu, Sha; Lin, Hai Xiang; Heemink, Arnold; Segers, Arjo; Fu, Guangliang

    2015-04-01

    Volcanic ash forecasting is a critical tool in hazard assessment and operational volcano monitoring. Emission parameters such as injection height, total emission mass and vertical distribution of the emission plume rate are essential and important in the implementation of volcanic ash models. Satellite instrument is a powerful tool to monitor volcanic aerosol evolution and satellite total-column data has been integrated in the modeling process to achieve a better initial condition for the forecasting. However, the use of total-column data,which has no vertical resolution, usually leads to an ill-conditioned problem and ineffective estimation of emission parameters. Fortunately, techniques to retrieve the information of total ash mass loading and injection height from satellite data has been developed recently. It provides a new possibility to increase the accuracy of estimation results by integrating them into data assimilation systems. In this work we propose a modified 4D-Var approach which seek the vertical emission distribution by observing ash cloud transport patterns from satellite total-ash-columns data, and two ways of including the information of mass loading and plume height in the assimilation process. The modified 4D-Var based on trajectory statistics forms a reformulated cost function which computes the total difference between observed ash columns and a linear combination of simulated ensemble columns coupled with a priori emission knowledge ('background' term). The ensembles are generated by a volcanic ash transport model with the tracer released form different layers. Experiment shows such straightforward method does not always guarantee the identification of injection height with a short assimilation time window, and additional information of injection height is needed to correct the solution. We propose two tricks to incorporate the information: 1. add extra terms containing the information to the cost function as restriction term; 2. generate a

  16. Volcanic ash in bare ice south of Sør Rondane Mountains, Antarctica: geochemistry, rock magnetism and nondestructive magnetic detection with SQUID gradiometer

    NASA Astrophysics Data System (ADS)

    Oda, Hirokuni; Miyagi, Isoji; Kawai, Jun; Suganuma, Yusuke; Funaki, Minoru; Imae, Naoya; Mikouchi, Takashi; Matsuzaki, Takuya; Yamamoto, Yuhji

    2016-03-01

    Nondestructive magnetic detection of tephra layers in ice cores will be an important method to identify and correlate stratigraphic horizons of ice bearing volcanic ash particles. Volcanic ash particles were extracted from tephra-bearing ice samples collected from Nansen Ice Field south of the Sør Rondane Mountains, Antarctica. Particles are fresh glassy volcanic ash with diameters of ~50 μm, and chemical composition of the matrix glass belongs to a low-K basaltic andesite group, ranging from SiO2 60-62 wt% and K2O 0.40-0.50 wt%. Considering the grain size of ash particles and chemical composition of volcanic glass, the ash in tephra-bearing ice samples might be originated from the South Sandwich Islands located 2800 km northwest of the sampling sites. Correlations on major element concentrations with tephra layers associated with South Sandwich Islands in EPICA-Dome C, Vostok, and Dome Fuji ice cores show high similarity. Rock magnetic experiments show that the magnetic mineral is pseudo-single-domain titanomagnetite with ulvospinel content of 0.2-0.35 mixed with single-domain to superparamagnetic (titano)magnetite. Small blocks of the tephra-bering ice were measured with a SQUID gradiometer at 1-mm intervals with a spatial resolution of ~3 mm. With DC magnetic field of 25 mT, magnetic signal could be enhanced and detected for all the samples including the one with invisible amount of tephra particles. In order to simulate a thin ash layer in ice core, volcanic ash particles extracted from the tephra-bearing ice were used to fabricate a thin ash layer, which were subsequently magnetized, measured with the gradiometer. The noise level for Z axis gradiometer was about 0.6 pT. Detection limit for a half-cylinder with 29 mm radius and a thickness of 1 mm uniformly magnetized in X axis direction is ~9 × 10-5 A/m, which could be improved down to ~2 × 10-6 A/m by reducing the sensor-to-sample distance to 0.5 mm.

  17. A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions

    NASA Astrophysics Data System (ADS)

    Mastin, L. G.; Guffanti, M.; Servranckx, R.; Webley, P.; Barsotti, S.; Dean, K.; Durant, A.; Ewert, J. W.; Neri, A.; Rose, W. I.; Schneider, D.; Siebert, L.; Stunder, B.; Swanson, G.; Tupper, A.; Volentik, A.; Waythomas, C. F.

    2009-09-01

    During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days in order to define hazards to aircraft and to communities downwind. Those models use input parameters, called "eruption source parameters", such as plume height H, mass eruption rate Ṁ, duration D, and the mass fraction m63 of erupted debris finer than about 4ϕ or 63 μm, which can remain in the cloud for many hours or days. Observational constraints on the value of such parameters are frequently unavailable in the first minutes or hours after an eruption is detected. Moreover, observed plume height may change during an eruption, requiring rapid assignment of new parameters. This paper reports on a group effort to improve the accuracy of source parameters used by VATDs in the early hours of an eruption. We do so by first compiling a list of eruptions for which these parameters are well constrained, and then using these data to review and update previously studied parameter relationships. We find that the existing scatter in plots of H versus Ṁ yields an uncertainty within the 50% confidence interval of plus or minus a factor of four in eruption rate for a given plume height. This scatter is not clearly attributable to biases in measurement techniques or to well-recognized processes such as elutriation from pyroclastic flows. Sparse data on total grain-size distribution suggest that the mass fraction of fine debris m63 could vary by nearly two orders of magnitude between small basaltic eruptions (˜ 0.01) and large silicic ones (> 0.5). We classify eleven eruption types; four types each for different sizes of silicic and mafic eruptions; submarine eruptions; "brief" or Vulcanian eruptions; and eruptions that generate co-ignimbrite or co-pyroclastic flow plumes. For each eruption type we assign source parameters. We then assign a characteristic eruption type to each of the world's ˜ 1500 Holocene

  18. A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions

    USGS Publications Warehouse

    Mastin, L.G.; Guffanti, M.; Servranckx, R.; Webley, P.; Barsotti, S.; Dean, K.; Durant, A.; Ewert, J.W.; Neri, A.; Rose, William I.; Schneider, D.; Siebert, L.; Stunder, B.; Swanson, G.; Tupper, A.; Volentik, A.; Waythomas, C.F.

    2009-01-01

    During volcanic eruptions, volcanic ash transport and dispersion models (VATDs) are used to forecast the location and movement of ash clouds over hours to days in order to define hazards to aircraft and to communities downwind. Those models use input parameters, called "eruption source parameters", such as plume height H, mass eruption rate ???, duration D, and the mass fraction m63 of erupted debris finer than about 4??{symbol} or 63????m, which can remain in the cloud for many hours or days. Observational constraints on the value of such parameters are frequently unavailable in the first minutes or hours after an eruption is detected. Moreover, observed plume height may change during an eruption, requiring rapid assignment of new parameters. This paper reports on a group effort to improve the accuracy of source parameters used by VATDs in the early hours of an eruption. We do so by first compiling a list of eruptions for which these parameters are well constrained, and then using these data to review and update previously studied parameter relationships. We find that the existing scatter in plots of H versus ??? yields an uncertainty within the 50% confidence interval of plus or minus a factor of four in eruption rate for a given plume height. This scatter is not clearly attributable to biases in measurement techniques or to well-recognized processes such as elutriation from pyroclastic flows. Sparse data on total grain-size distribution suggest that the mass fraction of fine debris m63 could vary by nearly two orders of magnitude between small basaltic eruptions (??? 0.01) and large silicic ones (> 0.5). We classify eleven eruption types; four types each for different sizes of silicic and mafic eruptions; submarine eruptions; "brief" or Vulcanian eruptions; and eruptions that generate co-ignimbrite or co-pyroclastic flow plumes. For each eruption type we assign source parameters. We then assign a characteristic eruption type to each of the world's ??? 1500

  19. Ash3d: A finite-volume, conservative numerical model for ash transport and tephra deposition

    USGS Publications Warehouse

    Schwaiger, Hans F.; Denlinger, Roger P.; Mastin, Larry G.

    2012-01-01

    We develop a transient, 3-D Eulerian model (Ash3d) to predict airborne volcanic ash concentration and tephra deposition during volcanic eruptions. This model simulates downwind advection, turbulent diffusion, and settling of ash injected into the atmosphere by a volcanic eruption column. Ash advection is calculated using time-varying pre-existing wind data and a robust, high-order, finite-volume method. Our routine is mass-conservative and uses the coordinate system of the wind data, either a Cartesian system local to the volcano or a global spherical system for the Earth. Volcanic ash is specified with an arbitrary number of grain sizes, which affects the fall velocity, distribution and duration of transport. Above the source volcano, the vertical mass distribution with elevation is calculated using a Suzuki distribution for a given plume height, eruptive volume, and eruption duration. Multiple eruptions separated in time may be included in a single simulation. We test the model using analytical solutions for transport. Comparisons of the predicted and observed ash distributions for the 18 August 1992 eruption of Mt. Spurr in Alaska demonstrate to the efficacy and efficiency of the routine.

  20. Volcanic Ash over Arizona in the Spring of 1982: Astronomical Observations.

    PubMed

    Livingston, W; Lockwood, G W

    1983-04-15

    Astronomical observations in Arizona recorded the passage of one, and possibly more, volcanic dust clouds between January and June 1982. On 15 May the increase in extinction in visible wavelengths at Tucson was more than 40 percent or 0.4 in optical depth. At Flagstaff, 325 kilometers north, the increase in extinction on the same day was 25 percent. A detailed time history of atmospheric extinction plus evidence for nongray absorption from the cloud is presented.

  1. A glacier peak and Mount Saint Helens J volcanic ash couplet and the timing of deglaciation in the Colville Valley area, Washington

    USGS Publications Warehouse

    Carrara, P.E.; Trimble, D.A.

    1992-01-01

    A Late Pleistocene volcanic ash couplet consisting of a glacier Peak ash layer and an underlying Mount Saint Helens J ash layer has been identified at three sites in the Colville Valley area of northeastern Washington. This ash couplet has been reported as far east as northwestern Montana and therefore appears to have widespread distribution south of the International Boundary. Because areas covered by the Cordilleran Ice Sheet, as well as by local mountain glaciers and icefields, were undergoing extensive deglaciation when these ash layers were deposited, about 11 200 BP, the ash couplet is an important time-stratigraphic marker, and its identification at a site provides information about the extent of deglaciation at that time. The presence of the Glacier Peak and Mount Saint Helens J ash couplet in the Colville Valley, about 50km north (upglacier) from the Late Wisconsin terminal moraine near the town of Springdale, indicates that the active margin of the Colville sublobe of the Cordilleran Ice Sheet had retreated at least that distance by 11 200 BP. -from Authors

  2. Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards: Part II. Validation of satellite-derived Volcanic Sulphur Dioxide Levels.

    NASA Astrophysics Data System (ADS)

    Koukouli, MariLiza; Balis, Dimitris; Dimopoulos, Spiros; Clarisse, Lieven; Carboni, Elisa; Hedelt, Pascal; Spinetti, Claudia; Theys, Nicolas; Tampellini, Lucia; Zehner, Claus

    2014-05-01

    The eruption of the Icelandic volcano Eyjafjallajökull in the spring of 2010 turned the attention of both the public and the scientific community to the susceptibility of the European airspace to the outflows of large volcanic eruptions. The ash-rich plume from Eyjafjallajökull drifted towards Europe and caused major disruptions of European air traffic for several weeks affecting the everyday life of millions of people and with a strong economic impact. This unparalleled situation revealed limitations in the decision making process due to the lack of information on the tolerance to ash of commercial aircraft engines as well as limitations in the ash monitoring and prediction capabilities. The European Space Agency project Satellite Monitoring of Ash and Sulphur Dioxide for the mitigation of Aviation Hazards, was introduced to facilitate the development of an optimal End-to-End System for Volcanic Ash Plume Monitoring and Prediction. This system is based on comprehensive satellite-derived ash plume and sulphur dioxide [SO2] level estimates, as well as a widespread validation using supplementary satellite, aircraft and ground-based measurements. The validation of volcanic SO2 levels extracted from the sensors GOME-2/MetopA and IASI/MetopA are shown here with emphasis on the total column observed right before, during and after the Eyjafjallajökull 2010 eruptions. Co-located ground-based Brewer Spectrophotometer data extracted from the World Ozone and Ultraviolet Radiation Data Centre, WOUDC, were compared to the different satellite estimates. The findings are presented at length, alongside a comprehensive discussion of future scenarios.

  3. Estimating Saturation with Depth in the Vadose Zone of Volcanic Ash Deposits

    NASA Astrophysics Data System (ADS)

    Gay, D.; Reppert, P. M.

    2003-12-01

    Surface geophysical measurements were conducted in a vast area of compacted ash deposits on the island of Dominica, West Indies. The seismic refraction data can be modeled as a power law velocity increasing with depth to the water table. Conversely, the electrical resistivity data fits a power law increasing in height from the water table. These two datasets/models are combined using basic rock physics models to predict the level of saturation from the surface to the water table. The geophysical predictions are compared to civil-engineering saturation profiles with depth.

  4. Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka.

    PubMed

    Lane, Christine S; Chorn, Ben T; Johnson, Thomas C

    2013-05-14

    The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has been attributed to the cooling effects of the ash and aerosols ejected during the eruption of the Youngest Toba Tuff (YTT). These events coincided roughly with a hypothesized human genetic bottleneck, when the number of our species in Africa may have been reduced to near extinction. Some have speculated that the demise of early modern humans at that time was due in part to a dramatic climate shift triggered by the supereruption. Others have argued that environmental conditions would not have been so severe to have such an impact on our ancestors, and furthermore, that modern humans may have already expanded beyond Africa by this time. We report an observation of the YTT in Africa, recovered as a cryptotephra layer in Lake Malawi sediments, >7,000 km west of the source volcano. The YTT isochron provides an accurate and precise age estimate for the Lake Malawi paleoclimate record, wh