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Sample records for activity volcanic eruptions

  1. Active Volcanic Eruptions on Io

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Six views of the volcanic plume named Prometheus, as seen against Io's disk and near the bright limb (edge) of the satellite by the SSI camera on the Galileo spacecraft during its second (G2) orbit of Jupiter. North is to the top of each frame. To the south-southeast of Prometheus is another bright spot that appears to be an active plume erupting from a feature named Culann Patera. Prometheus was active 17 years ago during both Voyager flybys, but no activity was detected by Voyager at Culann. Both of these plumes were seen to glow in the dark in an eclipse image acquired by the imaging camera during Galileo's first (G1) orbit, and hot spots at these locations were detected by Galileo's Near-Infrared Mapping Spectrometer.

    The plumes are thought to be driven by heating sulfur dioxide in Io's subsurface into an expanding fluid or 'geyser'. The long-lived nature of these eruptions requires that a substantial supply of sulfur dioxide must be available in Io's subsurface, similar to groundwater. Sulfur dioxide gas condenses into small particles of 'snow' in the expanding plume, and the small particles scatter light and appear bright at short wavelengths. The images shown here were acquired through the shortest-wavelength filter (violet) of the Galileo camera. Prometheus is about 300 km wide and 75 km high and Culann is about 150 km wide and less than 50 km high. The images were acquired on September 4, 1996 at a range of 2,000,000 km (20 km/pixel resolution). Prometheus is named after the Greek fire god and Culann is named after the Celtic smith god.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the

  2. Seasonality of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Mason, B. G.; Pyle, D. M.; Dade, W. B.; Jupp, T.

    2004-04-01

    An analysis of volcanic activity during the last three hundred years reveals that volcanic eruptions exhibit seasonality to a statistically significant degree. This remarkable pattern is observed primarily along the Pacific "Ring of Fire" and locally at some individual volcanoes. Globally, seasonal fluctuations amount to 18% of the historical average monthly eruption rate. In some regions, seasonal fluctuations amount to as much as 50% of the average eruption rate. Seasonality principally reflects the temporal distribution of the smaller, dated eruptions (volcanic explosivity index of 0-2) that dominate the eruption catalog. We suggest that the pattern of seasonality correlates with the annual Earth surface deformation that accompanies the movement of surface water mass during the annual hydrological cycle and illustrate this with respect to global models of surface deformation and regional measurements of annual sea level change. For example, seasonal peaks in the eruption rate of volcanoes in Central America, the Alaskan Peninsula, and Kamchatka coincide with periods of falling regional sea level. In Melanesia, in contrast, peak numbers of volcanic eruptions occur during months of maximal regional sea level and falling regional atmospheric pressure. We suggest that the well-documented slow deformation of Earth's surface that accompanies the annual movements of water mass from oceans to continents acts to impose a fluctuating boundary condition on volcanoes, such that volcanic eruptions tend to be concentrated during periods of local or regional surface change rather than simply being distributed randomly throughout the year. Our findings have important ramifications for volcanic risk assessment and volcanoclimate feedback mechanisms.

  3. Volcanic eruptions on Io

    NASA Astrophysics Data System (ADS)

    Strom, R. G.; Schneider, N. M.; Terrile, R. J.; Cook, A. F.; Hansen, C.

    1981-09-01

    Nine eruption plumes which were observed during the Voyager 1 encounter with Io are discussed. During the Voyager 2 encounter, four months later, eight of the eruptions were still active although the largest became inactive sometime between the two encounters. Plumes range in height from 60 to over 300 km with corresponding ejection velocities of 0.5 to 1.0 km/s and plume sources are located on several plains and consist of fissures or calderas. The shape and brightness distribution together with the pattern of the surface deposition on a plume 3 is simulated by a ballistic model with a constant ejection velocity of 0.5 km/s and ejection angles which vary from 0-55 deg. The distribution of active and recent eruptions is concentrated in the equatorial regions and indicates that volcanic activity is more frequent and intense in the equatorial regions than in the polar regions. Due to the geologic setting of certain plume sources and large reservoirs of volatiles required for the active eruptions, it is concluded that sulfur volcanism rather than silicate volcanism is the most likely driving mechanism for the eruption plumes.

  4. Volcanic eruptions observed with infrasound

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey B.; Aster, Richard C.; Kyle, Philip R.

    2004-07-01

    Infrasonic airwaves produced by active volcanoes provide valuable insight into the eruption dynamics. Because the infrasonic pressure field may be directly associated with the flux rate of gas released at a volcanic vent, infrasound also enhances the efficacy of volcanic hazard monitoring and continuous studies of conduit processes. Here we present new results from Erebus, Fuego, and Villarrica volcanoes highlighting uses of infrasound for constraining quantitative eruption parameters, such as eruption duration, source mechanism, and explosive gas flux.

  5. Volcanic Eruptions and Climate

    NASA Technical Reports Server (NTRS)

    LeGrande, Allegra N.; Anchukaitis, Kevin J.

    2015-01-01

    Volcanic eruptions represent some of the most climatically important and societally disruptive short-term events in human history. Large eruptions inject ash, dust, sulfurous gases (e.g. SO2, H2S), halogens (e.g. Hcl and Hbr), and water vapor into the Earth's atmosphere. Sulfurous emissions principally interact with the climate by converting into sulfate aerosols that reduce incoming solar radiation, warming the stratosphere and altering ozone creation, reducing global mean surface temperature, and suppressing the hydrological cycle. In this issue, we focus on the history, processes, and consequences of these large eruptions that inject enough material into the stratosphere to significantly affect the climate system. In terms of the changes wrought on the energy balance of the Earth System, these transient events can temporarily have a radiative forcing magnitude larger than the range of solar, greenhouse gas, and land use variability over the last millennium. In simulations as well as modern and paleoclimate observations, volcanic eruptions cause large inter-annual to decadal-scale changes in climate. Active debates persist concerning their role in longer-term (multi-decadal to centennial) modification of the Earth System, however.

  6. Volcanic eruption source parameters from active and passive microwave sensors

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario; Marzano, Frank S.; Cimini, Domenico; Mereu, Luigi

    2016-04-01

    It is well known, in the volcanology community, that precise information of the source parameters characterising an eruption are of predominant interest for the initialization of the Volcanic Transport and Dispersion Models (VTDM). Source parameters of main interest would be the top altitude of the volcanic plume, the flux of the mass ejected at the emission source, which is strictly related to the cloud top altitude, the distribution of volcanic mass concentration along the vertical column as well as the duration of the eruption and the erupted volume. Usually, the combination of a-posteriori field and numerical studies allow constraining the eruption source parameters for a given volcanic event thus making possible the forecast of ash dispersion and deposition from future volcanic eruptions. So far, remote sensors working at visible and infrared channels (cameras and radiometers) have been mainly used to detect, track and provide estimates of the concentration content and the prevailing size of the particles propagating within the ash clouds up to several thousand of kilometres far from the source as well as track back, a-posteriori, the accuracy of the VATDM outputs thus testing the initial choice made for the source parameters. Acoustic wave (infrasound) and microwave fixed scan radar (voldorad) were also used to infer source parameters. In this work we want to put our attention on the role of sensors operating at microwave wavelengths as complementary tools for the real time estimations of source parameters. Microwaves can benefit of the operability during night and day and a relatively negligible sensitivity to the presence of clouds (non precipitating weather clouds) at the cost of a limited coverage and larger spatial resolution when compared with infrared sensors. Thanks to the aforementioned advantages, the products from microwaves sensors are expected to be sensible mostly to the whole path traversed along the tephra cloud making microwaves particularly

  7. Early Detection of Volcanic Eruptions Using Lightning Activity in South America

    NASA Astrophysics Data System (ADS)

    Nicora, M. G.; Bürgesser, R. E.; Quel, E. J.; Avila, E.

    2013-05-01

    A study of the lightning activity produced by the eruption of the Cordón Caulle volcano during June 2011 was performed by using the World Wide Lightning Location Network data. The observed lightning activity corresponds to the electrical activity of the volcanic plume with a good correlation between the amount of lightning detected and the volcanic plume height. Although the detected lightning activity was low, the results agree with previous studies and show that lightning activity could be use as a proxy of the volcanic activity. This study also shows the feasibility on the use of the network for early detection of volcanic eruptions. The Global Volcanic Lightning Monitor is an experimental research project, based on the World Wide Lightning Location Network data, which sent an alert of the eruption of the Cordón Caulle volcanic complex before the report of the National Service of Geology and Mining (SERNAGEOMIN) of Chile. This demonstrate the relevance of the system as support of national warning systems (if any) and, where there are no continuous monitoring of eruptive systems, as early warning of volcanic eruptions.

  8. Can vesicle size distributions predict eruption intensity during volcanic activity?

    NASA Astrophysics Data System (ADS)

    LaRue, A.; Baker, D. R.; Polacci, M.; Allard, P.; Sodini, N.

    2013-06-01

    We studied three-dimensional (3-D) vesicle size distributions by X-ray microtomography in scoria collected during the relatively quiescent Phase II of the 2010 eruption at Eyjafjallajökull volcano, Iceland. Our goal was to compare the vesicle size distributions (VSDs) measured in these samples with those found in Stromboli volcano, Italy. Stromboli was chosen because its VSDs are well-characterized and show a correlation with eruption intensity: typical Strombolian activity produces VSDs with power-law exponents near 1, whereas larger and more energetic Vulcanian-type explosions and Plinian eruptions produce VSDs with power-law exponents near 1.5. The hypothesis to be tested was whether or not the samples studied in this work would contain VSDs similar to normal Strombolian products, display higher power-law exponents, or be described by exponential functions. Before making this comparison we tested the hypothesis that the phreatomagmatic nature of the Eyjafjallajökull eruption might have a significant effect on the VSDs. We performed 1 atm bubble-growth experiments in which the samples were inundated with water and compared them to similar, control, experiments without water inundation. No significant differences between the VSDs of the two sets of experiments were found, and the hypothesis is not supported by the experimental evidence; therefore, VSDs of magmatic and phreatomagmatic eruptions can be directly compared. The Phase II Eyjafjallajökull VSDs are described by power law exponents of ~ 0.8, typical of normal Strombolian eruptions. The comparable VSDs and behavior of Phase II of the Eyjafjallajökull 2010 eruption to Stromboli are interpreted to be a reflection of similar conduit systems in both volcanoes that are being constantly fed by the ascent of deep magma that mixes with resident magma at shallow depths. Such behavior implies that continued activity during Phase II of the Eyjafjallajökull eruption could be expected and would have been predicted

  9. Aspects of historical eruptive activity and volcanic unrest at Mt. Tongariro, New Zealand: 1846-2013

    NASA Astrophysics Data System (ADS)

    Scott, Bradley J.; Potter, Sally H.

    2014-10-01

    The 6 August and 21 November 2012 eruptions from Upper Te Maari crater have heightened interest in past activity at Mt. Tongariro, New Zealand. Risks caused by volcanic hazards are increasingly being quantified by using probability estimates through expert elicitation, partly based on the frequency of past eruptions. To maximise the accuracy of these risk values at Mt. Tongariro, a historical eruption catalogue is required. This paper presents the findings of a detailed historical chronology of unrest and eruptions at Mt. Tongariro between 1846 AD and 2013 AD. It builds on the findings of previous researchers, highlighting that volcanic eruptions and unrest have occurred frequently from this volcano. Eruptions are now thought to have occurred at Mt. Tongariro in 1869, 1892, 1896-97, 1899, 1926, 1927, 1934 and 2012. Eruptions also potentially occurred in 1846, 1855, 1886, and 1928, in addition to frequent eruptions from neighbouring Mt. Ngauruhoe. The number of recognised eruptions during the 1896-97 episode has increased to 18, and the Red Crater area has been found to be more active than previously appreciated. Multiple episodes of unrest not resulting in eruptions have also been identified. New eruption recurrence rates are derived from this catalogue, with the baseline probability of the onset of an eruption episode calculated to be 0.07 per year (if 1896-97 and 2012 are considered as one episode each, and all others separately), and the maximum eruption rate within an eruption episode is 18 per year. These new data contribute towards risk assessments for future eruptions at Mt. Tongariro.

  10. Volcanic Eruptions and Climate

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2012-12-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of these aerosol clouds produce responses in the climate system. Observations and numerical models of the climate system show that volcanic eruptions produce global cooling and were the dominant natural cause of climate change for the past millennium, on timescales from annual to century. Major tropical eruptions produce winter warming of Northern Hemisphere continents for one or two years, while high latitude eruptions in the Northern Hemisphere weaken the Asian and African summer monsoon. The Toba supereruption 74,000 years ago caused very large climate changes, affecting human evolution. However, the effects did not last long enough to produce widespread glaciation. An episode of four large decadally-spaced eruptions at the end of the 13th century C.E. started the Little Ice Age. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade had a small effect on global temperature trends. The June 13, 2011 Nabro eruption in Eritrea produced the largest stratospheric aerosol cloud since Pinatubo, and the most of the sulfur entered the stratosphere not by direct injection, but by slow lofting in the Asian summer monsoon circulation. Volcanic eruptions warn us that while stratospheric geoengineering could cool the surface, reducing ice melt and sea level rise, producing pretty sunsets, and increasing the CO2 sink, it could also reduce summer monsoon precipitation, destroy ozone, allowing more harmful UV at the surface, produce rapid warming when stopped, make the sky white, reduce solar power, perturb the ecology with more diffuse radiation, damage airplanes flying in the stratosphere, degrade astronomical observations, affect remote sensing, and affect

  11. Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

    USGS Publications Warehouse

    Thomas, Ronald J.; Krehbiel, Paul R.; Rison, William; Edens, H. E.; Aulich, G. D.; McNutt, S.R.; Tytgat, Guy; Clark, E.

    2007-01-01

    By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

  12. Electrical activity during the 2006 Mount St. Augustine volcanic eruptions.

    PubMed

    Thomas, R J; Krehbiel, P R; Rison, W; Edens, H E; Aulich, G D; Winn, W P; McNutt, S R; Tytgat, G; Clark, E

    2007-02-23

    By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms. PMID:17322054

  13. Can rain cause volcanic eruptions?

    USGS Publications Warehouse

    Mastin, Larry G.

    1993-01-01

    Volcanic eruptions are renowned for their violence and destructive power. This power comes ultimately from the heat and pressure of molten rock and its contained gases. Therefore we rarely consider the possibility that meteoric phenomena, like rainfall, could promote or inhibit their occurrence. Yet from time to time observers have suggested that weather may affect volcanic activity. In the late 1800's, for example, one of the first geologists to visit the island of Hawaii, J.D. Dana, speculated that rainfall influenced the occurrence of eruptions there. In the early 1900's, volcanologists suggested that some eruptions from Mount Lassen, Calif., were caused by the infiltration of snowmelt into the volcano's hot summit. Most such associations have not been provable because of lack of information; others have been dismissed after careful evaluation of the evidence.

  14. Volcanic Eruptions in Kamchatka

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Sheveluch Stratovolcano Click on the image for full resolution TIFF Klyuchevskoy Stratovolcano Click on the image for full resolution TIFF

    One of the most volcanically active regions of the world is the Kamchatka Peninsula in eastern Siberia, Russia. It is not uncommon for several volcanoes to be erupting at the same time. On April 26, 2007, the Advanced Spaceborne Thermal Emission and Reflection Radioneter (ASTER) on NASA's Terra spacecraft captured these images of the Klyuchevskoy and Sheveluch stratovolcanoes, erupting simultaneously, and 80 kilometers (50 miles) apart. Over Klyuchevskoy, the thermal infrared data (overlaid in red) indicates that two open-channel lava flows are descending the northwest flank of the volcano. Also visible is an ash-and-water plume extending to the east. Sheveluch volcano is partially cloud-covered. The hot flows highlighted in red come from a lava dome at the summit. They are avalanches of material from the dome, and pyroclastic flows.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining

  15. Models of volcanic eruption hazards

    SciTech Connect

    Wohletz, K.H.

    1992-01-01

    Volcanic eruptions pose an ever present but poorly constrained hazard to life and property for geothermal installations in volcanic areas. Because eruptions occur sporadically and may limit field access, quantitative and systematic field studies of eruptions are difficult to complete. Circumventing this difficulty, laboratory models and numerical simulations are pivotal in building our understanding of eruptions. For example, the results of fuel-coolant interaction experiments show that magma-water interaction controls many eruption styles. Applying these results, increasing numbers of field studies now document and interpret the role of external water eruptions. Similarly, numerical simulations solve the fundamental physics of high-speed fluid flow and give quantitative predictions that elucidate the complexities of pyroclastic flows and surges. A primary goal of these models is to guide geologists in searching for critical field relationships and making their interpretations. Coupled with field work, modeling is beginning to allow more quantitative and predictive volcanic hazard assessments.

  16. Aurorae and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  17. A statistical method linking geological and historical eruption time series for volcanic hazard estimations: Applications to active polygenetic volcanoes

    NASA Astrophysics Data System (ADS)

    Mendoza-Rosas, Ana Teresa; De la Cruz-Reyna, Servando

    2008-09-01

    The probabilistic analysis of volcanic eruption time series is an essential step for the assessment of volcanic hazard and risk. Such series describe complex processes involving different types of eruptions over different time scales. A statistical method linking geological and historical eruption time series is proposed for calculating the probabilities of future eruptions. The first step of the analysis is to characterize the eruptions by their magnitudes. As is the case in most natural phenomena, lower magnitude events are more frequent, and the behavior of the eruption series may be biased by such events. On the other hand, eruptive series are commonly studied using conventional statistics and treated as homogeneous Poisson processes. However, time-dependent series, or sequences including rare or extreme events, represented by very few data of large eruptions require special methods of analysis, such as the extreme-value theory applied to non-homogeneous Poisson processes. Here we propose a general methodology for analyzing such processes attempting to obtain better estimates of the volcanic hazard. This is done in three steps: Firstly, the historical eruptive series is complemented with the available geological eruption data. The linking of these series is done assuming an inverse relationship between the eruption magnitudes and the occurrence rate of each magnitude class. Secondly, we perform a Weibull analysis of the distribution of repose time between successive eruptions. Thirdly, the linked eruption series are analyzed as a non-homogeneous Poisson process with a generalized Pareto distribution as intensity function. As an application, the method is tested on the eruption series of five active polygenetic Mexican volcanoes: Colima, Citlaltépetl, Nevado de Toluca, Popocatépetl and El Chichón, to obtain hazard estimates.

  18. Aurorae and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    2001-06-01

    Thermal-IR Observations of Jupiter and Io with ISAAC at the VLT Summary Impressive thermal-infrared images have been obtained of the giant planet Jupiter during tests of a new detector in the ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory (Chile). . They show in particular the full extent of the northern auroral ring and part of the southern aurora. A volcanic eruption was also imaged on Io , the very active inner Jovian moon. Although these observations are of an experimental nature, they demonstrate a great potential for regular monitoring of the Jovian magnetosphere by ground-based telescopes together with space-based facilities. They also provide the added benefit of direct comparison with the terrestrial magnetosphere. PR Photo 21a/01 : ISAAC image of Jupiter (L-band: 3.5-4.0 µm) . PR Photo 21b/01 : ISAAC image of Jupiter (Narrow-band 4.07 µm) . PR Photo 21c/01 : ISAAC image of Jupiter (Narrow-band 3.28 µm) . PR Photo 21d/01 : ISAAC image of Jupiter (Narrow-band 3.21 µm) . PR Photo 21e/01 : ISAAC image of the Jovian aurorae (false-colour). PR Photo 21f/01 : ISAAC image of volcanic activity on Io . Addendum : The Jovian aurorae and polar haze. Aladdin Meets Jupiter Thermal-infrared images of Jupiter and its volcanic moon Io have been obtained during a series of system tests with the new Aladdin detector in the Infrared Spectrometer And Array Camera (ISAAC) , in combination with an upgrade of the ESO-developed detector control electronics IRACE. This state-of-the-art instrument is attached to the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory. The observations were made on November 14, 2000, through various filters that isolate selected wavebands in the thermal-infrared spectral region [1]. They include a broad-band L-filter (wavelength interval 3.5 - 4.0 µm) as well as several narrow-band filters (3.21, 3.28 and 4.07 µm). The filters allow to record the light from different components of the Jovian atmosphere

  19. 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

  20. Infrasound research of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Marchetti, Emanuele; Ripepe, Maurizio

    2016-04-01

    Volcanic eruptions are efficient sources of infrasound produced by the rapid perturbation of the atmosphere by the explosive source. Being able to propagate up to large distances from the source, infrasonic waves from major (VEI 4 or larger) volcanic eruptions have been recorded for many decades with analogue micro-barometers at large regional distances. In late 1980s, near-field observations became progressively more common and started to have direct impact on the understanding and modeling of explosive source dynamics, to eventually play a primary role in volcano research. Nowadays, infrasound observation from a large variety of volcanic eruptions, spanning from VEI 0 to VEI 5 events, has shown a dramatic variability in terms of signature, excess pressure and frequency content of radiated infrasound and has been used to infer complex eruptive source mechanisms for the different kinds of events. Improved processing capability and sensors has allowed unprecedented precise locations of the explosive source and is progressively increasing the possibility to monitor volcanoes from distant records. Very broadband infrasound observations is also showing the relation between volcanic eruptions and the atmosphere, with the eruptive mass injection in the atmosphere triggering acoustic-gravity waves which eventually might control the ash dispersal and fallout.

  1. The intensities and magnitudes of volcanic eruptions

    USGS Publications Warehouse

    Sigurdsson, H.

    1991-01-01

    Ever since 1935, when C.F Richter devised the earthquake magnitude scale that bears his name, seismologists have been able to view energy release from earthquakes in a systematic and quantitative manner. The benefits have been obvious in terms of assessing seismic gaps and the spatial and temporal trends of earthquake energy release. A similar quantitative treatment of volcanic activity is of course equally desirable, both for gaining a further understanding of the physical principles of volcanic eruptions and for volcanic-hazard assessment. A systematic volcanologic data base would be of great value in evaluating such features as volcanic gaps, and regional and temporal trends in energy release.  

  2. Sub-glacial volcanic eruptions

    USGS Publications Warehouse

    White, Donald Edward

    1956-01-01

    The literature on sub-glacial volcanic eruptions and the related flood phenomena has been reviewed as a minor part of the larger problem of convective and conductive heat transfer from intrusive magma. (See Lovering, 1955, for a review of the extensive literature on this subject.) This summary of data on sub-glacial eruptions is part of a program that the U.S. Geological Survey is conducting in connection with its Investigations of Geologic Processes project on behalf of the Division of Research, U.S. Atomic Energy Commission.

  3. Localization of Volcanic Activity: Topographic Effects on Dike Propagation, Eruption and COnduit Formation

    SciTech Connect

    E.S. Gaffney; B. Damjanac

    2006-05-12

    Magma flow in a dike rising in a crack whose strike runs from a highland or a ridge to an adjacent lowland has been modeled to determine the effect of topography on the flow. It is found that there is a distinct tendency for the flow to be diverted away from the highland end of the strike toward the lowland. Separation of the geometric effect of the topography from its effect on lateral confining stresses on the crack indicates that both contribute to the effect but that the effect of stress is less important. Although this analysis explains a tendency for volcanic eruptions to occur in low lands, it does not preclude eruptions on highlands. The particular configuration modeled mimics topography around the proposed nuclear waste repository at Yucca Mountain, Nevada, so that the results may indicate some reduction in the volcanic hazard to the site.

  4. Volcanic Lightning in Eruptions of Sakurajima Volcano

    NASA Astrophysics Data System (ADS)

    Edens, Harald; Thomas, Ronald; Behnke, Sonja; McNutt, Stephen; Smith, Cassandra; Farrell, Alexandra; Van Eaton, Alexa; Cimarelli, Corrado; Cigala, Valeria; Eack, Ken; Aulich, Graydon; Michel, Christopher; Miki, Daisuke; Iguchi, Masato

    2016-04-01

    In May 2015 a field program was undertaken to study volcanic lightning at the Sakurajima volcano in southern Japan. One of the main goals of the study was to gain a better understanding of small electrical discharges in volcanic eruptions, expanding on our earlier studies of volcanic lightning at Augustine and Redoubt volcanoes in Alaska, USA, and Eyjafjallajökull in Iceland. In typical volcanic eruptions, electrical activity occurs at the onset of an eruption as a near-continual production of VHF emissions at or near to the volcanic vent. These emissions can occur at rates of up to tens of thousands of emissions per second, and are referred to as continuous RF. As the ash cloud expands, small-scale lightning flashes of several hundred meters length begin to occur while the continuous RF ceases. Later on during the eruption larger-scale lightning flashes may occur within the ash cloud that are reminiscent of regular atmospheric lightning. Whereas volcanic lightning flashes are readily observed and reasonably well understood, the nature and morphology of the events producing continuous RF are unknown. During the 2015 field program we deployed a comprehensive set of instrumentation, including a 10-station 3-D Lightning Mapping Array (LMA) that operated in 10 μs high time resolution mode, slow and fast ΔE antennas, a VHF flat-plate antenna operating in the 20-80 MHz band, log-RF waveforms within the 60-66 MHz band, an infra-red video camera, a high-sensitivity Watec video camera, two high-speed video cameras, and still cameras. We give an overview of the Sakurajima field program and present preliminary results using correlated LMA, waveforms, photographs and video recordings of volcanic lightning at Sakurajima volcano.

  5. Volcanic activity in the Acambay Graben: a < 25 Ka subplinian eruption from the Temascalcingo volcano and implications for volcanic hazard.

    NASA Astrophysics Data System (ADS)

    Pedrazzi, Dario; Aguirre Díaz, Gerardo; Sunyé Puchol, Ivan; Bartolini, Stefania; Geyer, Adelina

    2016-04-01

    The Trans-Mexican Volcanic Belt (TMVB) contains a large number of stratovolcanoes, some well-known, as Popocatepetl, Iztaccihuatl, Nevado de Toluca, or Colima and many others of more modest dimensions that are not well known but constitute the majority in the TMVB. Such volcanoes are, for example, Tequila, San Juan, Sangangüey, Cerro Culiacán, Cerro Grande, El Zamorano, La Joya, Palo Huerfano, Jocotitlán, Altamirano and Temascalcingo, among many others. The Temascalcingo volcano (TV) is an andesitic-dacitic stratovolcano located in the Trans-Mexican Volcanic Belt (TMVB) at the eastern part of the Acambay Graben (northwest portion of Estado de México). The TV is composed mainly by dacitic, porphyritic lavas, block and ash deposits and subordinate pumice fall deposits and ignimbrites (Roldán-Quintana et al., 2011). The volcanic structure includes a summit caldera that has a rectangular shape, 2.5×3.5 km, with the largest side oriented E-W, parallel to major normal faults affecting the edifice. The San Mateo Pumice eruption is one of the greatest paroxysmal episodes of this volcano with pumice deposits mainly exposed at the scarp of the Acambay-Tixmadeje fault and at the northern and northeastern flanks of TV. It overlies a paleosol dated at 25 Ka. A NE-trending dispersion was obtained from field data covering an area of at least 80 km2. These deposits overlie older lava flows and mud flows and are discontinuously covered and eroded by younger reworked deposits of Temascalcingo volcano. This event represents a highly explosive phase that generated a relatively thick and widespread pumice fallout deposit that may occur again in future eruptions. A similar eruption today would have a significantly impact in the region, overall due to the fact that there has been no systematic assessment of the volcanic hazard in any of the studies that have been conducted so far in the area. So, this is a pending and urgent subject that must be tackled without delay. Financed by

  6. Climatic impact of volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.

    1991-01-01

    Studies have attempted to 'isolate' the volcanic signal in noisy temperature data. This assumes that it is possible to isolate a distinct volcanic signal in a record that may have a combination of forcings (ENSO, solar variability, random fluctuations, volcanism) that all interact. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on temperatures in regions where the effects of aerosol clouds may be amplified by perturbed atmospheric circulation patterns. This is especially true in subpolar and midlatitude areas affected by changes in the position of the polar front. Such climatic perturbation can be detected in proxy evidence such as decrease in tree-ring widths and frost rings, changes in the treeline, weather anomalies, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures. In low latitudes, sudden temperature drops were correlated with the passage overhead of the volcanic dust cloud (Stothers, 1984). For some eruptions, such as Tambora, 1815, these kinds of proxy and anectdotal information were summarized in great detail in a number of papers and books (e.g., Post, 1978; Stothers, 1984; Stommel and Stommel, 1986; C. R. Harrington, in press). These studies lead to the general conclusion that regional effects on climate, sometimes quite severe, may be the major impact of large historical volcanic aerosol clouds.

  7. Potential hazards from future volcanic eruptions in California

    SciTech Connect

    Miller, C.D.

    1989-01-01

    More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the last 10,000 yr. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Volcanoes in California will erupt again, and they could have serious impacts on the health, safety, and economy of the State's citizens as well as that of neighboring states. The nature and probable distribution of potentially hazardous volcanic phenomena and their threat to people and property is described in this bulletin.

  8. Two types of volcanic tremor changed with eruption style during 1986 Izu-Oshima eruption

    NASA Astrophysics Data System (ADS)

    Kurokawa, Aika; Takeo, Minoru; Kurita, Kei

    2016-04-01

    Volcanic tremor provides clues to magma migration pathways so that tremor source location is expected to be an efficient tool for tracking dynamic behavior of magma in evolution of eruptive activity. However, clear evidence, which connects between temporal variation in volcanic tremor and evolution of eruption style, is still lacking. We have analyzed volcanic tremors occurred during 1986 Izu-Oshima eruption using recently digitized data. The results present a clear link between eruption styles, waveform variations and source locations of the tremors. Moreover, precursory activity of the tremors that indicates injection of magma below fissures has been clarified 5 days prior to the fissure eruptions. This demonstrates predominance of tremor activity as an adaptive monitoring tool in volcanic eruption.

  9. Exploring a long-lasting volcanic eruption by means of in-soil radon measurements and seismic activity

    NASA Astrophysics Data System (ADS)

    Falsaperla, Susanna; Neri, Marco; Di Grazia, Giuseppe; Langer, Horst; Spampinato, Salvatore

    2016-04-01

    We analyze in-soil radon (Rn) emission and ambient parameters (barometric pressure and air temperature measurements) along with seismic activity during the longest flank eruption of this century at Mt. Etna, Italy. This eruption occurred between 14 May 2008 and 6 July 2009, from a N120-140°E eruptive fissure extending between 3050 and 2620 m above sea level. It was heralded by a short-lived (~5 hours) episode of lava fountaining three days before a dike-forming intrusion fed a lava emission, which affected the summit area of the volcano over ~15 months. The peculiar position of the station for the Rn measurement, which was at an altitude of 2950 m above sea level and near (~1 km) the summit active craters, offered us the uncommon chance: i) to explore the temporal development of the gas emission close (<2 km) to the 2008-2009 eruptive vents in the long term, and ii) to analyze the relationship between in-soil Rn fluxes and seismic signals (in particular, local earthquakes and volcanic tremor) during the uninterrupted lava emission. This approach reveals important details about the recharging phases characterizing the 2008-2009 eruption, which are not visible with other methods of investigation. Our study benefitted from the application of methods of pattern classification developed in the framework of the European MEDiterrranean Supersite Volcanoes (MED­SUV) project.

  10. Learning to recognize volcanic non-eruptions

    USGS Publications Warehouse

    Poland, Michael P.

    2010-01-01

    An important goal of volcanology is to answer the questions of when, where, and how a volcano will erupt—in other words, eruption prediction. Generally, eruption predictions are based on insights from monitoring data combined with the history of the volcano. An outstanding example is the A.D. 1980–1986 lava dome growth at Mount St. Helens, Washington (United States). Recognition of a consistent pattern of precursors revealed by geophysical, geological, and geochemical monitoring enabled successful predictions of more than 12 dome-building episodes (Swanson et al., 1983). At volcanic systems that are more complex or poorly understood, probabilistic forecasts can be useful (e.g., Newhall and Hoblitt, 2002; Marzocchi and Woo, 2009). In such cases, the probabilities of different types of volcanic events are quantified, using historical accounts and geological studies of a volcano's past activity, supplemented by information from similar volcanoes elsewhere, combined with contemporary monitoring information.

  11. Thermal vesiculation during volcanic eruptions.

    PubMed

    Lavallée, Yan; Dingwell, Donald B; Johnson, Jeffrey B; Cimarelli, Corrado; Hornby, Adrian J; Kendrick, Jackie E; von Aulock, Felix W; Kennedy, Ben M; Andrews, Benjamin J; Wadsworth, Fabian B; Rhodes, Emma; Chigna, Gustavo

    2015-12-24

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the 'strength' of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  12. Thermal vesiculation during volcanic eruptions.

    PubMed

    Lavallée, Yan; Dingwell, Donald B; Johnson, Jeffrey B; Cimarelli, Corrado; Hornby, Adrian J; Kendrick, Jackie E; von Aulock, Felix W; Kennedy, Ben M; Andrews, Benjamin J; Wadsworth, Fabian B; Rhodes, Emma; Chigna, Gustavo

    2015-12-24

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the 'strength' of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  13. Thermal vesiculation during volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Lavallée, Yan; Dingwell, Donald B.; Johnson, Jeffrey B.; Cimarelli, Corrado; Hornby, Adrian J.; Kendrick, Jackie E.; von Aulock, Felix W.; Kennedy, Ben M.; Andrews, Benjamin J.; Wadsworth, Fabian B.; Rhodes, Emma; Chigna, Gustavo

    2015-12-01

    Terrestrial volcanic eruptions are the consequence of magmas ascending to the surface of the Earth. This ascent is driven by buoyancy forces, which are enhanced by bubble nucleation and growth (vesiculation) that reduce the density of magma. The development of vesicularity also greatly reduces the ‘strength’ of magma, a material parameter controlling fragmentation and thus the explosive potential of the liquid rock. The development of vesicularity in magmas has until now been viewed (both thermodynamically and kinetically) in terms of the pressure dependence of the solubility of water in the magma, and its role in driving gas saturation, exsolution and expansion during decompression. In contrast, the possible effects of the well documented negative temperature dependence of solubility of water in magma has largely been ignored. Recently, petrological constraints have demonstrated that considerable heating of magma may indeed be a common result of the latent heat of crystallization as well as viscous and frictional heating in areas of strain localization. Here we present field and experimental observations of magma vesiculation and fragmentation resulting from heating (rather than decompression). Textural analysis of volcanic ash from Santiaguito volcano in Guatemala reveals the presence of chemically heterogeneous filaments hosting micrometre-scale vesicles. The textures mirror those developed by disequilibrium melting induced via rapid heating during fault friction experiments, demonstrating that friction can generate sufficient heat to induce melting and vesiculation of hydrated silicic magma. Consideration of the experimentally determined temperature and pressure dependence of water solubility in magma reveals that, for many ascent paths, exsolution may be more efficiently achieved by heating than by decompression. We conclude that the thermal path experienced by magma during ascent strongly controls degassing, vesiculation, magma strength and the effusive

  14. Soil gas radon and volcanic activity at El Hierro (Canary Islands) before and after the 2011-2012 submarine eruption

    NASA Astrophysics Data System (ADS)

    Barrancos, J.; Padilla, G.; Hernandez Perez, P. A.; Padron, E.; Perez, N.; Melian Rodriguez, G.; Nolasco, D.; Dionis, S.; Rodriguez, F.; Calvo, D.; Hernandez, I.

    2012-12-01

    El Hierro is the youngest and southernmost island of the Canarian archipelago and represents the summit of a volcanic shield elevating from the surrounding seafloor at depth of 4000 m to up to 1501 m above sea level. The island is believed to be near the present hotspot location in the Canaries with the oldest subaerial rocks dated at 1.12 Ma. The subaerial parts of the El Hierro rift zones (NE, NW and S Ridges) are characterized by tightly aligned dyke complexes with clusters of cinder cones as their surface expressions. Since July 16, 2011, an anomalous seismicity at El Hierro Island was recorded by IGN seismic network. Volcanic tremor started at 05:15 hours on October 10, followed on the afternoon of October 12 by a green discolouration of seawater, strong bubbling and degassing indicating the initial stage of submarine volcanic eruption at approximately 2 km off the coast of La Restinga, El Hierro. Soil gas 222Rn and 220Rn activities were continuously measured during the period of the recent volcanic unrest occurred at El Hierro, at two different geochemical stations, HIE02 and HIE03. Significant increases in soil 222Rn activity and 222Rn/220Rn ratio from the soil were observed at both stations prior the submarine eruption off the coast of El Hierro, showing the highest increases before the eruption onset and the occurrence of the strongest seismic event (M=4.6). A statistical analysis showed that the long-term trend of the filtered data corresponded closely to the seismic energy released during the volcanic unrest. The observed increases of 222Rn are related to the rock fracturing processes (seismic activity) and the magmatic CO2 outflow increase, as observed in HIE03 station. Under these results, we find that continuous soil radon studies are important for evaluating the volcanic activity of El Hierro and they demonstrate the potential of applying continuous monitoring of soil radon to improve and optimize the detection of early warning signals of future

  15. Volcanic eruptions; energy and size

    USGS Publications Warehouse

    de la Cruz-Reyna, S.

    1991-01-01

    The Earth is a dynamic planet. Many different processes are continuously developing, creating a delicate balance between the energy stored and generated in its interior and the heat lost into space. The heat in continuously transferred through complex self-regulating convection mechanisms on a planetary scale. The distribution of terrestrial heat flow reveals some of the fine structure of the energy transport mechanisms in the outer layers of the Earth. Of these mechanisms in the outer layers of the Earth. Of these mechanisms, volcanism is indeed the most remarkable, for it allows energy to be transported in rapid bursts to the surface. In order to maintain the subtle balance of the terrestrial heat machine, one may expect that some law or principle restricts the ways in which these volcanic bursts affect the overall energy transfer of the Earth. For instance, we know that the geothermal flux of the planet amounts to 1028 erg/year. On the other hand, a single large event like the Lava Creek Tuff eruption that formed Yellowstone caldera over half a million years ago may release the same amount of energy in a very small area, over a short period of time. 

  16. Volcanic Eruptions and Climate: Outstanding Research Issues

    NASA Astrophysics Data System (ADS)

    Robock, Alan

    2016-04-01

    Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about one year. The radiative and chemical effects of this aerosol cloud produce responses in the climate system. Based on observations after major eruptions of the past and experiments with numerical models of the climate system, we understand much about their climatic impact, but there are also a number of unanswered questions. Volcanic eruptions produce global cooling, and are an important natural cause of interannual, interdecadal, and even centennial-scale climate change. One of the most interesting volcanic effects is the "winter warming" of Northern Hemisphere continents following major tropical eruptions. During the winter in the Northern Hemisphere following every large tropical eruption of the past century, surface air temperatures over North America, Europe, and East Asia were warmer than normal, while they were colder over Greenland and the Middle East. This pattern and the coincident atmospheric circulation correspond to the positive phase of the Arctic Oscillation. While this response is observed after recent major eruptions, most state-of-the-art climate models have trouble simulating winter warming. Why? High latitude eruptions in the Northern Hemisphere, while also producing global cooling, do not have the same impact on atmospheric dynamics. Both tropical and high latitude eruptions can weaken the Indian and African summer monsoon, and the effects can be seen in past records of flow in the Nile and Niger Rivers. Since the Mt. Pinatubo eruption in the Philippines in 1991, there have been no large eruptions that affected climate, but the cumulative effects of small eruptions over the past decade have had a small effect on global temperature trends. Some important outstanding research questions include: How much seasonal, annual, and decadal predictability is possible following a large volcanic eruption? Do

  17. Winter warming from large volcanic eruptions

    SciTech Connect

    Robock, A.; Mao, J.

    1992-01-01

    An examination of the Northern Hemisphere winter surface temperature patterns after the 12 largest volcanic eruptions from 1883-1992 shows warming over Eurasia and North America and cooling over the Middle East which are significant at the 95 percent level. This pattern is found in the first winter after tropical eruptions, in the first or second winter after midlatitude eruptions, and in the second winter after high latitude eruptions. The effects are independent of the hemisphere of the volcanoes. An enhanced zonal wind driven by heating of the tropical stratosphere by the volcanic aerosols is responsible for the regions of warming, while the cooling is caused by blocking of incoming sunlight.

  18. Assessment of the atmospheric impact of volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Sigurdsson, H.

    1988-01-01

    The dominant global impact of volcanic activity is likely to be related to the effects of volcanic gases on the Earth's atmosphere. Volcanic gas emissions from individual volcanic arc eruptions are likely to cause increases in the stratospheric optical depth that result in surface landmass temperature decline of 2 to 3 K for less than a decade. Trachytic and intermediate magmas are much more effective in this regard than high-silica magmas, and may also lead to extensive ozone depletion due to effect of halogens and magmatic water. Given the assumed relationship between arc volcanism and subduction rate, and the relatively small variation in global spreading rates in the geologic record, it is unlikely that the rates of arc volcanism have varied greatly during the Cenozoic. Hotspot related basaltic fissure eruptions in the subaerial environment have a higher mass yield of sulfur, but lofting of the valcanic aerosol to levels above the tropopause is required for a climate impact. High-latitude events, such as the Laki 1783 eruption can easily penetrate the tropopause and enter the stratosphere, but formation of a stratospheric volcanic aerosol form low-latitude effusive basaltic eruptions is problematical, due to the elevated low-latitude tropopause. Due to the high sulfur content of hotspot-derived basaltic magmas, their very high mass eruption rates and the episodic behavior, hotspots must be regarded as potentially major modifiers of Earth's climate through the action of their volcanic volatiles on the chemistry and physics of the atmosphere.

  19. Kamchatkan Volcanic Eruption Response Team (KVERT), Russia: preventing the danger of volcanic eruptions to aviation.

    NASA Astrophysics Data System (ADS)

    Girina, O.; Neal, Ch.

    2012-04-01

    The Kamchatkan Volcanic Eruption Response Team (KVERT) has been a collaborative project of scientists from the Institute of Volcanology and Seismology, the Kamchatka Branch of Geophysical Surveys, and the Alaska Volcano Observatory (IVS, KB GS and AVO). The purpose of KVERT is to reduce the risk of costly, damaging, and possibly deadly encounters of aircraft with volcanic ash clouds. To reduce this risk, KVERT collects all possible volcanic information and issues eruption alerts to aviation and other emergency officials. KVERT was founded by Institute of Volcanic Geology and Geochemistry FED RAS in 1993 (in 2004, IVGG merged with the Institute of Volcanology to become IVS). KVERT analyzes volcano monitoring data (seismic, satellite, visual and video, and pilot reports), assigns the Aviation Color Code, and issues reports on eruptive activity and unrest at Kamchatkan (since 1993) and Northern Kurile (since 2003) volcanoes. KVERT receives seismic monitoring data from KB GS (the Laboratory for Seismic and Volcanic Activity). KB GS maintains telemetered seismic stations to investigate 11 of the most active volcanoes in Kamchatka. Data are received around the clock and analysts evaluate data each day for every monitored volcano. Satellite data are provided from several sources to KVERT. AVO conducts satellite analysis of the Kuriles, Kamchatka, and Alaska as part of it daily monitoring and sends the interpretation to KVERT staff. KVERT interprets MODIS and MTSAT images and processes AVHRR data to look for evidence of volcanic ash and thermal anomalies. KVERT obtains visual volcanic information from volcanologist's field trips, web-cameras that monitor Klyuchevskoy (established in 2000), Sheveluch (2002), Bezymianny (2003), Koryaksky (2009), Avachinsky (2009), Kizimen (2011), and Gorely (2011) volcanoes, and pilots. KVERT staff work closely with staff of AVO, AMC (Airport Meteorological Center) at Yelizovo Airport and the Tokyo Volcanic Ash Advisory Center (VAAC), the

  20. Steam explosions, earthquakes, and volcanic eruptions -- what's in Yellowstone's future?

    USGS Publications Warehouse

    Lowenstern, Jacob B.; Christiansen, Robert L.; Smith, Robert B.; Morgan, Lisa A.; Heasler, Henry

    2005-01-01

    Yellowstone, one of the world?s largest active volcanic systems, has produced several giant volcanic eruptions in the past few million years, as well as many smaller eruptions and steam explosions. Although no eruptions of lava or volcanic ash have occurred for many thousands of years, future eruptions are likely. In the next few hundred years, hazards will most probably be limited to ongoing geyser and hot-spring activity, occasional steam explosions, and moderate to large earthquakes. To better understand Yellowstone?s volcano and earthquake hazards and to help protect the public, the U.S. Geological Survey, the University of Utah, and Yellowstone National Park formed the Yellowstone Volcano Observatory, which continuously monitors activity in the region.

  1. Volcview: A Web-Based Platform for Satellite Monitoring of Volcanic Activity and Eruption Response

    NASA Astrophysics Data System (ADS)

    Schneider, D. J.; Randall, M.; Parker, T.

    2014-12-01

    The U.S. Geological Survey (USGS), in cooperation with University and State partners, operates five volcano observatories that employ specialized software packages and computer systems to process and display real-time data coming from in-situ geophysical sensors and from near-real-time satellite sources. However, access to these systems both inside and from outside the observatory offices are limited in some cases by factors such as software cost, network security, and bandwidth. Thus, a variety of Internet-based tools have been developed by the USGS Volcano Science Center to: 1) Improve accessibility to data sources for staff scientists across volcano monitoring disciplines; 2) Allow access for observatory partners and for after-hours, on-call duty scientists; 3) Provide situational awareness for emergency managers and the general public. Herein we describe VolcView (volcview.wr.usgs.gov), a freely available, web-based platform for display and analysis of near-real-time satellite data. Initial geographic coverage is of the volcanoes in Alaska, the Russian Far East, and the Commonwealth of the Northern Mariana Islands. Coverage of other volcanoes in the United States will be added in the future. Near-real-time satellite data from NOAA, NASA and JMA satellite systems are processed to create image products for detection of elevated surface temperatures and volcanic ash and SO2 clouds. VolcView uses HTML5 and the canvas element to provide image overlays (volcano location and alert status, annotation, and location information) and image products that can be queried to provide data values, location and measurement capabilities. Use over the past year during the eruptions of Pavlof, Veniaminof, and Cleveland volcanoes in Alaska by the Alaska Volcano Observatory, the National Weather Service, and the U.S. Air Force has reinforced the utility of shared situational awareness and has guided further development. These include overlay of volcanic cloud trajectory and

  2. Supercomputer modeling of volcanic eruption dynamics

    SciTech Connect

    Kieffer, S.W.; Valentine, G.A.; Woo, Mahn-Ling

    1995-06-01

    Our specific goals are to: (1) provide a set of models based on well-defined assumptions about initial and boundary conditions to constrain interpretations of observations of active volcanic eruptions--including movies of flow front velocities, satellite observations of temperature in plumes vs. time, and still photographs of the dimensions of erupting plumes and flows on Earth and other planets; (2) to examine the influence of subsurface conditions on exit plane conditions and plume characteristics, and to compare the models of subsurface fluid flow with seismic constraints where possible; (3) to relate equations-of-state for magma-gas mixtures to flow dynamics; (4) to examine, in some detail, the interaction of the flowing fluid with the conduit walls and ground topography through boundary layer theory so that field observations of erosion and deposition can be related to fluid processes; and (5) to test the applicability of existing two-phase flow codes for problems related to the generation of volcanic long-period seismic signals; (6) to extend our understanding and simulation capability to problems associated with emplacement of fragmental ejecta from large meteorite impacts.

  3. Multistation alarm system for eruptive activity based on the automatic classification of volcanic tremor: specifications and performance

    NASA Astrophysics Data System (ADS)

    Langer, Horst; Falsaperla, Susanna; Messina, Alfio; Spampinato, Salvatore

    2015-04-01

    With over fifty eruptive episodes (Strombolian activity, lava fountains, and lava flows) between 2006 and 2013, Mt Etna, Italy, underscored its role as the most active volcano in Europe. Seven paroxysmal lava fountains at the South East Crater occurred in 2007-2008 and 46 at the New South East Crater between 2011 and 2013. Month-lasting lava emissions affected the upper eastern flank of the volcano in 2006 and 2008-2009. On this background, effective monitoring and forecast of volcanic phenomena are a first order issue for their potential socio-economic impact in a densely populated region like the town of Catania and its surroundings. For example, explosive activity has often formed thick ash clouds with widespread tephra fall able to disrupt the air traffic, as well as to cause severe problems at infrastructures, such as highways and roads. For timely information on changes in the state of the volcano and possible onset of dangerous eruptive phenomena, the analysis of the continuous background seismic signal, the so-called volcanic tremor, turned out of paramount importance. Changes in the state of the volcano as well as in its eruptive style are usually concurrent with variations of the spectral characteristics (amplitude and frequency content) of tremor. The huge amount of digital data continuously acquired by INGV's broadband seismic stations every day makes a manual analysis difficult, and techniques of automatic classification of the tremor signal are therefore applied. The application of unsupervised classification techniques to the tremor data revealed significant changes well before the onset of the eruptive episodes. This evidence led to the development of specific software packages related to real-time processing of the tremor data. The operational characteristics of these tools - fail-safe, robustness with respect to noise and data outages, as well as computational efficiency - allowed the identification of criteria for automatic alarm flagging. The

  4. Tectonic Windows Reveal Off-axis Volcanic and Hydrothermal Activity and Along-strike Variations in Eruption Effusion Rates

    NASA Astrophysics Data System (ADS)

    MacDonald, K. C.

    2005-12-01

    Alvin transects of faulted escarpments 50-500m high provide tectonic windows to investigate the top 500m of oceanic crustal structure and lava stratigraphy. The Alvin archives were used to review dives from the East Pacific Rise, the Mid-Atlantic Ridge, the Juan de Fuca Ridge, the Blanco Trough, Cayman Trough and the Galapagos Spreading Center. A spreading rate dependence in lava morphology based solely on areal coverage(Bonatti and Harrison, 1988) was confirmed in scarp transects: mostly pillow lavas at slow spreading rates and sheet flows/lobate flows at faster spreading rates. More interestingly; there is a systematic variation within first, second and third order segments on intermediate and fast-spreading centers such that sheet/lobate flows dominate at segment centers and pillow flows and lava domes are more common at segment ends. This confirms earlier studies which were based on areal coverage (White et al, 2000, 2002, Soule et al 2005). This suggests higher eruption effusion rates and perhaps higher magma pressure and lower magma viscosity at segment centers relative to segment ends. This has important implications for the relationship between segmentation, magma supply, volcanism and hydrothermal activity (Haymon and White 2005). A conundrum remains; based on areal photographic surveys, why are pillow lavas so much more common off-axis than on-axis for intermediate to fast-spreading ridges? If there is an eruption cycle in which sheeted and lobate flows dominate early on, and pillow lavas dominate the waning stages of eruption (e.g. Ballard et al 1979), then more pillow lavas should be seen on axis than are seen on-axis in either areal or transect data. Another explanation is that pillow lavas off-axis are primarily produced by off-axis eruptions (except near segment ends, they may also occur as the pillowed terminations of channeled sheet and lobate flows; the association with channels will make this obvious.) Off-axis volcanism is also indicated by a

  5. Understanding Volcanic Conduit Dynamics: from Experimental Fragmentation to Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Arciniega-Ceballos, A.; Alatorre-Ibarguengoitia, M. A.; Scheu, B.; Dingwell, D. B.

    2011-12-01

    and the effects of such process on the conduit dynamics are independent of size. We first described the very-long period (VLP) and long-period (LP) signals, observed in many active volcanoes around the world, and from comparison of waveform characteristics with their experimental analogues (eLP and eVLP signals) we found remarkable similarities and equivalent physical meaning. Based on our experimental investigations and analysis of field data recorded during volcanic eruptions we may conclude that VLP signals are caused by the inflation-deflation behavior of the volcanic conduit due to the decompression process, and that LP signals are manly associated with cracking and fragmentation of the magmatic material (ash, magma and gas) filling the conduit and ascending to the surface. In addition, we accounted for the repetitive character of LP and VLP signals, as a consequence of contraction and dilatation of a steady non-destructive source mechanism, which systematically responds to pressure changes of the volcanic system.

  6. Database for potential hazards from future volcanic eruptions in California

    USGS Publications Warehouse

    White, Melissa N.; Ramsey, David W.; Miller, C. Dan

    2011-01-01

    More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the past 10,000 yr. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Sooner or later, volcanoes in California will erupt again, and they could have serious impacts on the health and safety of the State's citizens as well as on its economy. This report describes the nature and probable distribution of potentially hazardous volcanic phenomena and their threat to people and property. It includes hazard-zonation maps that show areas relatively likely to be affected by future eruptions in California. This digital release contains information from maps of potential hazards from future volcanic eruptions in the state of California, published as Plate 1 in U.S. Geological Survey Bulletin 1847. The main component of this digital release is a spatial database prepared using geographic information systems (GIS) applications. This release also contains links to files to view or print the map plate, main report text, and accompanying hazard tables from Bulletin 1847. It should be noted that much has been learned about the ages of eruptive events in the State of California since the publication of Bulletin 1847 in 1989. For the most up to date information on the status of California volcanoes, please refer to the U.S. Geological Survey Volcano Hazards Program website.

  7. Geomorphic consequences of volcanic eruptions in Alaska: A review

    NASA Astrophysics Data System (ADS)

    Waythomas, Christopher F.

    2015-10-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta-Katmai eruption, the 1989-1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed. A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment-water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite large

  8. Geomorphic Consequences of Volcanic Eruptions in Alaska: A Review

    USGS Publications Warehouse

    Waythomas, Christopher F.

    2015-01-01

    Eruptions of Alaska volcanoes have significant and sometimes profound geomorphic consequences on surrounding landscapes and ecosystems. The effects of eruptions on the landscape can range from complete burial of surface vegetation and preexisting topography to subtle, short-term perturbations of geomorphic and ecological systems. In some cases, an eruption will allow for new landscapes to form in response to the accumulation and erosion of recently deposited volcaniclastic material. In other cases, the geomorphic response to a major eruptive event may set in motion a series of landscape changes that could take centuries to millennia to be realized. The effects of volcanic eruptions on the landscape and how these effects influence surface processes has not been a specific focus of most studies concerned with the physical volcanology of Alaska volcanoes. Thus, what is needed is a review of eruptive activity in Alaska in the context of how this activity influences the geomorphology of affected areas. To illustrate the relationship between geomorphology and volcanic activity in Alaska, several eruptions and their geomorphic impacts will be reviewed. These eruptions include the 1912 Novarupta–Katmai eruption, the 1989–1990 and 2009 eruptions of Redoubt volcano, the 2008 eruption of Kasatochi volcano, and the recent historical eruptions of Pavlof volcano. The geomorphic consequences of eruptive activity associated with these eruptions are described, and where possible, information about surface processes, rates of landscape change, and the temporal and spatial scale of impacts are discussed.A common feature of volcanoes in Alaska is their extensive cover of glacier ice, seasonal snow, or both. As a result, the generation of meltwater and a variety of sediment–water mass flows, including debris-flow lahars, hyperconcentrated-flow lahars, and sediment-laden water floods, are typical outcomes of most types of eruptive activity. Occasionally, such flows can be quite

  9. Preventive health measures in volcanic eruptions.

    PubMed Central

    Baxter, P J; Bernstein, R S; Buist, A S

    1986-01-01

    Medical treatment has only a small role in severe volcanic eruptions and so preventive measures are paramount if injuries and loss of life are to be reduced. The health team must be incorporated in emergency planning and response at the earliest stage. Guidance on the interpretation of geological information about a volcano and the appropriate health measures that should be adopted before and after an eruption are summarized for the benefit of health workers. PMID:3946731

  10. Interactions between human activity, volcanic eruptions and vegetation during the Holocene at Garua and Numundo, West New Britain, PNG

    NASA Astrophysics Data System (ADS)

    Boyd, W. E.; Lentfer, C. J.; Parr, J.

    2005-11-01

    This paper reviews recent fossil phytolith analysis from wet tropical West New Britain (Papua New Guinea). The Holocene vegetation has been influenced by spatially and temporally diverse patterns of both prehistoric human settlement and catastrophic volcanic events. We have hypothesized different landscape responses and recovery pathways to events during the last six millennia. Phytolith sequences on the coastal lowlands, the Willaumez Peninsula, and nearby island of Garua provide details of vegetational change and human interactions at different landscape scales since c. 5900 cal yr B.P. During this period four major volcanic eruptions (c. 5900, 3600, 1700 and 1400 cal yr B.P.) have disrupted the landscape. The evidence provides detailed descriptions of temporal and spatial patterning in the impacts and changes in the vegetation. In particular, vegetation responded differently from one event to another, reflecting both forest recovery from seed bank and shooting, and the influence of prehistoric people on recovering vegetation. Furthermore, after some events landscape recovery was moderately uniform, while after others there was considerable landscape partitioning. Although these differences largely relate to airfall tephra type, distribution and magnitude, the partitioning is more strongly influenced by human activity.

  11. Volcan Baru: Eruptive History and Volcano-Hazards Assessment

    USGS Publications Warehouse

    Sherrod, David R.; Vallance, James W.; Tapia Espinosa, Arkin; McGeehin, John P.

    2008-01-01

    Volcan Baru is a potentially active volcano in western Panama, about 35 km east of the Costa Rican border. The volcano has had four eruptive episodes during the past 1,600 years, including its most recent eruption about 400?500 years ago. Several other eruptions occurred in the prior 10,000 years. Several seismic swarms in the 20th century and a recent swarm in 2006 serve as reminders of a restless tectonic terrane. Given this history, Volcan Baru likely will erupt again in the near or distant future, following some premonitory period of seismic activity and subtle ground deformation that may last for days or months. Future eruptions will likely be similar to past eruptions?explosive and dangerous to those living on the volcano?s flanks. Outlying towns and cities could endure several years of disruption in the wake of renewed volcanic activity. Described in this open-file report are reconnaissance mapping and stratigraphic studies, radiocarbon dating, lahar-inundation modeling, and hazard-analysis maps. Existing data have been compiled and included to make this report as comprehensive as possible. The report is prepared in coooperation with National Secretariat for Science, Technology and Innovation (SENACYT) of the Republic of Panama and the U.S. Agency for International Development (USAID).

  12. Eruption processes and deposit characteristics at the monogenetic Mt. Gambier Volcanic Complex, SE Australia: implications for alternating magmatic and phreatomagmatic activity

    NASA Astrophysics Data System (ADS)

    van Otterloo, Jozua; Cas, Raymond A. F.; Sheard, Malcolm J.

    2013-08-01

    The ˜5 ka Mt. Gambier Volcanic Complex in the Newer Volcanics Province, Australia is an extremely complex monogenetic, volcanic system that preserves at least 14 eruption points aligned along a fissure system. The complex stratigraphy can be subdivided into six main facies that record alternations between magmatic and phreatomagmatic eruption styles in a random manner. The facies are (1) coherent to vesicular fragmental alkali basalt (effusive/Hawaiian spatter and lava flows); (2) massive scoriaceous fine lapilli with coarse ash (Strombolian fallout); (3) bedded scoriaceous fine lapilli tuff (violent Strombolian fallout); (4) thin-medium bedded, undulating very fine lapilli in coarse ash (dry phreatomagmatic surge-modified fallout); (5) palagonite-altered, cross-bedded, medium lapilli to fine ash (wet phreatomagmatic base surges); and (6) massive, palagonite-altered, very poorly sorted tuff breccia and lapilli tuff (phreato-Vulcanian pyroclastic flows). Since most deposits are lithified, to quantify the grain size distributions (GSDs), image analysis was performed. The facies are distinct based on their GSDs and the fine ash to coarse+fine ash ratios. These provide insights into the fragmentation intensities and water-magma interaction efficiencies for each facies. The eruption chronology indicates a random spatial and temporal sequence of occurrence of eruption styles, except for a "magmatic horizon" of effusive activity occurring at both ends of the volcanic complex simultaneously. The eruption foci are located along NW-SE trending lineaments, indicating that the complex was fed by multiple dykes following the subsurface structures related to the Tartwaup Fault System. Possible factors causing vent migration along these dykes and changes in eruption styles include differences in magma ascent rates, viscosity, crystallinity, degassing and magma discharge rate, as well as hydrological parameters.

  13. Modulations of stratospheric ozone by volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Blanchette, Christian; Mcconnell, John C.

    1994-01-01

    We have used a time series of aerosol surface based on the measurements of Hofmann to investigate the modulation of total column ozone caused by the perturbation to gas phase chemistry by the reaction N2O5(gas) + H2O(aero) yields 2HNO3(gas) on the surface of stratospheric aerosols. We have tested a range of values for its reaction probability, gamma = 0.02, 0.13, and 0.26 which we compared to unperturbed homogeneous chemistry. Our analysis spans a period from Jan. 1974 to Oct. 1994. The results suggest that if lower values of gamma are the norm then we would expect larger ozone losses for highly enhanced aerosol content that for larger values of gamma. The ozone layer is more sensitive to the magnitude of the reaction probability under background conditions than during volcanically active periods. For most conditions, the conversion of NO2 to HNO3 is saturated for reaction probability in the range of laboratory measurements, but is only absolutely saturated following major volcanic eruptions when the heterogeneous loss dominates the losses of N2O5. The ozone loss due to this heterogeneous reaction increases with the increasing chlorine load. Total ozone losses calculated are comparable to ozone losses reported from TOMS and Dobson data.

  14. Critical review of a new volcanic eruption chronology

    NASA Astrophysics Data System (ADS)

    Neuhäuser, Dagmar L.; Neuhäuser, Ralph

    2016-04-01

    Sigl. et al. (2015, Nature) present historical evidence for 32 volcanic eruptions to evaluate their new polar ice core 10-Be chronology - 24 are dated within three years of sulfur layers in polar ice. Most of them can be interpreted as weather phenomena (Babylonia: disk of sun like moon, reported for only one day, e.g. extinction due to clouds), Chinese sunspot reports (pellet, black vapor, etc.), solar eclipses, normal ice-halos and coronae (ring, bow, etc.), one aurora (redness), red suns due to mist drops in wet fog or fire-smoke, etc. Volcanic dust may facilitate detections of sunspots and formation of Bishop's ring, but tend to inhibit ice-halos, which are otherwise often reported in chronicles. We are left with three reports possibly indicating volcanic eruptions, namely fulfilling genuine criteria for atmospheric disturbances due to volcanic dust, e.g. bluish or faint sun, orange sky, or fainting of stars for months (BCE 208, 44-42, and 32). Among the volcanic eruptions used to fix the chronology (CE 536, 626, 939, 1257), the reports cited for the 930s deal only with 1-2 days, at least one reports an eclipse. In the new chronology, there is a sulfur detection eight years after the Vesuvius eruption, but none in CE 79. It may appear surprising that, from BCE 500 to 1, all five northern sulfur peaks labeled in figure 2 in Sigl et al. are systematically later by 2-4 years than the (corresponding?) southern peaks, while all five southern peaks from CE 100 to 600 labeled in figure 2 are systematically later by 1-4 years than the (corresponding?) northern peaks. Furthermore, in most of their six strongest volcanic eruptions, temperatures decreased years before their sulfur dating - correlated with weak solar activity as seen in radiocarbon, so that volcanic climate forcing appears dubious here. Also, their 10-Be peaks at CE 775 and 994 are neither significant nor certain in dating.

  15. Spatial and Temporal Evolution of Eruptive Activity in a Youthful Extensional Setting: the Case of the Nyamulagira Volcanic Field, Western Branch of the East African Rift

    NASA Astrophysics Data System (ADS)

    Smets, B.; Kervyn, M.; d'Oreye, N.; Kervyn, F.

    2014-12-01

    Nyamulagira is the westernmost volcano of the Virunga volcanic province, in the western branch of the East African Rift. This shield volcano is one of the most active African volcanoes with one eruption every 1-4 year(s). Nyamulagira's eruptions usually occur along the flanks of the main edifice and in the lava plain, producing pyroclastic cone(s) and 10-20 km-long lava flows. Between 1913 and 1938, the activity was however restricted to the summit caldera, where lava fountains progressively gave birth to a lava lake, which disappeared in 1938 during the partial collapse of the summit caldera and the onset of a 2.5 years-long flank eruption. The location of flank eruptions and the orientation of the eruptive fissures are strongly influenced by the edifice loading, and by the NNW-SSE fracture network that crosses the main edifice and link it to the neighboring Nyiragongo volcano. But rift fault can also influence fissure orientations and cone alignments, especially for distal events. The flank eruptions typically have similar characteristics, lasting few days to few weeks, with an average of 20-30 days. Less frequently, flank eruptions can be larger and more complex, lasting several months and/or emitting much larger volumes of lava. By combining historical and recent observations, we suggest that magma overpressure at shallow depth is the main cause of flank events. Major eruptions seem to be related to a deeper source able to trigger large magma injections through deep structures, such as rift faults. Since April 2012, the activity of Nyamulagira is restricted to the summit caldera, with continuous and intense gas emissions and, since mid-2014, by lava fountains. This change in eruptive behavior, if it persists, may leads to the emergence of a new lava lake and may significantly decreases the frequency of flank events

  16. Potential hazards from future volcanic eruptions in California

    USGS Publications Warehouse

    Miller, C. Dan

    1989-01-01

    More than 500 volcanic vents have been identified in the State of California. At least 76 of these vents have erupted, some repeatedly, during the last 10,000 years. Past volcanic activity has ranged in scale and type from small rhyolitic and basaltic eruptions through large catastrophic rhyolitic eruptions. Sooner or later, volcanoes in California will erupt again, and they could have serious impacts on the health and safety of the State\\'s citizens as well as on its economy. This report describes the nature and probable distribution of potentially hazardous volcanic phenomena and their threat to people and property. It includes hazard-zonation maps that show areas relatively likely to be affected by future eruptions in California. The potentially more hazardous eruptions in the State are those that involve explosive eruption of large volumes of silicic magma. Such eruptions could occur at vents in as many as four areas in California. They could eject pumice high into the atmosphere above the volcano, produce destructive blasts, avalanches, or pyroclastic flows that reach distances of tens of kilometers from a vent, and produce mudflows and floods that reach to distances of hundreds of kilometers. Smaller eruptions produce similar, but less severe and less extensive, phenomena. Hazards are greatest close to a volcanic vent; the slopes on or near a volcano, and valleys leading away from it, are affected most often and most severely by such eruptions. In general, risk from volcanic phenomena decreases with increasing distance from a vent and, for most flowage processes, with increasing height above valley floors or fan surfaces. Tephra (ash) from explosive eruptions can affect wide areas downwind from a vent. In California, prevailing winds cause the 180-degree sector east of the volcano to be affected most often and most severely. Risk to life from ashfall decreases rapidly with increasing distance from a vent, but thin deposits of ash could disrupt communication

  17. Experimental insights into transient volcanic eruption

    NASA Astrophysics Data System (ADS)

    Alatorre-Ibarguengoitia, M.; Scheu, B.; Dingwell, D. B.; Ramos-Hernandez, S.; de Arcia, P.

    2014-12-01

    The explosive expansion of mixtures of pressurized gases and pyroclasts within volcanic conduits and volcanic flows is a complex process that cannot be directly observed. Here, we present the results of shock-tube experiments with volcanic particles which exhibit remarkable similarities to the ejection dynamics of transient eruptions. Upon rapid decompression (from 2-11 MPa argon pressure to atmospheric pressure Pa = 0.1 MPa), loose particles are vertically accelerated and ejected into a large tank filled with air at atmospheric conditions. Our experimental results show that: 1) time-scales of the mechanical coupling between pyroclasts and the gas phase control the mixture dynamics and different regimes can be defined in terms of the Stokes number according to the particles grain-size; 2) As suggested by previous studies, we found that the pseudo-gas approximation is a reasonable approximation in transient eruptions only under certain conditions (constrained here experimentally); 3) the non-linear decay of the particles velocities with time is related with the conduit depth and the initial volume of the expanding material. Our results broaden the impact of previous experimental studies and provide fundamental information for numerical models of eruptive dynamics.

  18. Volcanic hazards. A sourcebook on the effects of eruptions

    SciTech Connect

    Blong, R.J.

    1984-01-01

    This volume examines the diverse effects of volcanic eruptions on people and their activities using examples and case studies. Eight broad groups of volcanic hazards - lava flows, ash (tephra) falls, pyroclastic flows, lahars (mudflows), volcanogenic earthquakes, volcanogenic tsunami, atmospheric phenomena such as shock waves and lightening strikes, and acid rains and gases - are identified and discussed. The social effects of eruptions are discussed, including human perceptions, mental health problems, evacuation, panic, rumors, disaster relief, religious beliefs, and longer-term social changes. Attention is also given to the effects of volcanic hazards on agriculture and other forms of economic activity. Throughout the book suggestions are made indicating ways in which casualties and damage may be reduced.

  19. Eruption-induced modifications to volcanic seismicity at Ruapehu, New Zealand, and its implications for eruption forecasting

    USGS Publications Warehouse

    Bryan, C.J.; Sherburn, S.

    2003-01-01

    Broadband seismic data collected on Ruapehu volcano, New Zealand, in 1994 and 1998 show that the 1995-1996 eruptions of Ruapehu resulted in a significant change in the frequency content of tremor and volcanic earthquakes at the volcano. The pre-eruption volcanic seismicity was characterized by several independent dominant frequencies, with a 2 Hz spectral peak dominating the strongest tremor and volcanic earthquakes and higher frequencies forming the background signal. The post-eruption volcanic seismicity was dominated by a 0.8-1.4 Hz spectral peak not seen before the eruptions. The 2 Hz and higher frequency signals remained, but were subordinate to the 0.8-1.4 Hz energy. That the dominant frequencies of volcanic tremor and volcanic earthquakes were identical during the individual time periods prior to and following the 1995-1996 eruptions suggests that during each of these time periods the volcanic tremor and earthquakes were generated by the same source process. The overall change in the frequency content, which occurred during the 1995-1996 eruptions and remains as of the time of the writing of this paper, most likely resulted from changes in the volcanic plumbing system and has significant implications for forecasting and real-time assessment of future eruptive activity at Ruapehu.

  20. Explosive volcanism on Hecates Tholus, Mars - Investigation of eruption conditions

    NASA Technical Reports Server (NTRS)

    Mouginis-Mark, P. J.; Head, J. W., III; Wilson, L.

    1982-01-01

    From a reexamination of the medium and high-resolution Viking images of Amazonian and Hesperian age volcanic centers on Mars, it is believed that an excellent example of well-preserved explosive activity does indeed exist close to the summit of Hecates Tholus. A mantled region to the west of the summit caldera is seen as an example of a geologically very recent plinian air fall ash deposit. Morphological evidence is presented for describing this as explosively generated material, and numerical models of magma ascent and eruption in the Martian environment are used to estimate the physical characteristics (eruption cloud height, magma discharge rate, magma volatile content, duration of activity, and vent size) for this event. Attention is also given to the implication of this eruptive style for the composition of the erupted magma.

  1. 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

  2. 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

  3. The largest volcanic eruptions on Earth

    NASA Astrophysics Data System (ADS)

    Bryan, Scott E.; Peate, Ingrid Ukstins; Peate, David W.; Self, Stephen; Jerram, Dougal A.; Mawby, Michael R.; Marsh, J. S. (Goonie); Miller, Jodie A.

    2010-10-01

    silicic eruptions, however, are moderately to highly explosive, producing co-current pyroclastic fountains (rarely Plinian) with discharge rates of 10 9-10 11 kg s -1 that emplace welded to rheomorphic ignimbrites. At present, durations for the large-magnitude silicic eruptions are unconstrained; at discharge rates of 10 9 kg s -1, equivalent to the peak of the 1991 Mt Pinatubo eruption, the largest silicic eruptions would take many months to evacuate > 5000 km 3 of magma. The generally simple deposit structure is more suggestive of short-duration (hours to days) and high intensity (~ 10 11 kg s -1) eruptions, perhaps with hiatuses in some cases. These extreme discharge rates would be facilitated by multiple point, fissure and/or ring fracture venting of magma. Eruption frequencies are much elevated for large-magnitude eruptions of both magma types during LIP-forming episodes. However, in basalt-dominated provinces (continental and ocean basin flood basalt provinces, oceanic plateaus, volcanic rifted margins), large magnitude (> M8) basaltic eruptions have much shorter recurrence intervals of 10 3-10 4 years, whereas similar magnitude silicic eruptions may have recurrence intervals of up to 10 5 years. The Paraná-Etendeka province was the site of at least nine > M8 silicic eruptions over an ~ 1 Myr period at ~ 132 Ma; a similar eruption frequency, although with a fewer number of silicic eruptions is also observed for the Afro-Arabian Province. The huge volumes of basaltic and silicic magma erupted in quick succession during LIP events raises several unresolved issues in terms of locus of magma generation and storage (if any) in the crust prior to eruption, and paths and rates of ascent from magma reservoirs to the surface. Available data indicate four end-member magma petrogenetic pathways in LIPs: 1) flood basalt magmas with primitive, mantle-dominated geochemical signatures (often high-Ti basalt magma types) that were either transferred directly from melting regions in

  4. 1980 volcanic eruption reported on Marion Island

    NASA Astrophysics Data System (ADS)

    Verwoerd, Wilhelm J.; Russell, Shaun; Berruti, Aldo

    1981-06-01

    The first volcanic eruption in the recorded history of Marion Island (46°54'S, 37°45'E) occurred between February and October 1980 at a locality on the west coast. It was a minor event that passed unnoticed at the meteorological station 20 km distant. The discovery was made on November 4, by five expedition members who walked around the island. When examined in more detail on November 25, the lava was still warm in places and numerous fumaroles existed. Three blocky flows emanated from two adjacent cinder cones built-up on a pre-existing phreatomagmatic tuff cone known as Kaalkoppie. The largest flow covers an area of about seven hectares and a further two hectares have been inundated by ash. Another flow poured seawards to form a new beach front, blocking access to what was previously the largest elephant seal wallowing ground on the island. No earth tremors were felt and the activity seems to have ended for the time being.

  5. Eruptive history of the Elysium Volcanic Province of Mars

    NASA Technical Reports Server (NTRS)

    Tanaka, Kenneth L.; Scott, David H.

    1987-01-01

    New geologic mapping of the Elysium volcanic province at 1:2,000,000 scale and crater counts provide a basis for describing its overall eruptive history. Four stages are listed and described in order of their relative age. They are also distinguished by eruption style and location. Stage 1: Central volcanism at Hecates and Albor Tholi. Stage 2: Shield and complex volcanism at Elysium Mons and Elysium Fossae. Stage 3: Rille volcanism at Elysium Fossae and Utopia Planitia. Stage 4: Flood lava and pyroclastic eruptions at Hecates Tholus and Elysium Mons. Tectonic and channeling activity in the Elysium region is intimately associated with volcanism. Recent work indicates that isostatic uplift of Tharsis, loading by Elysium Mons, and flexural uplift of the Elysium rise produced the stresses responsible for the fracturing and wrinkle-ridge formation in the region. Coeval faulting and channel formation almost certainly occurred in the pertinent areas in Stages 2 to 4. Older faults east of the lava flows and channels on Hecates Tholus may be coeval with Stage 1.

  6. Volcanic Eruption: Students Develop a Contingency Plan

    NASA Astrophysics Data System (ADS)

    Meisinger, Philipp; Wittlich, Christian

    2013-04-01

    Dangerous, loud, sensational, exciting - natural hazards have what it takes to get students attention around the globe. Arising interest is the first step to develop an intrinsic motivation to learn about the matter and endure the hardships that students might discover along the way of the unit. Natural hazards thereby establish a close-knit connection between physical and anthropological geography through analyzing the hazardous event and its consequences for the people living in the affected area. Following a general principle of didactics we start searching right on our doorsteps to offer students the possibility to gain knowledge on the familiar and later transfer it to the unknown example. Even in Southwest Germany - a region that is rather known for its wine than its volcanic activity - we can find a potentially hazardous region. The "Laacher See" volcano (a caldera lake) in northern Rhineland-Palatinate is according to Prof. H.U. Schminke a "potentially active volcano" . Its activity can be proven by seismic activities, or experienced when visiting the lake's southeastern shore, where carbondioxid and sulphur gases from the underlying magma chamber still bubble up. The Laacher See is part of a range of volcanoes (classified from 'potentially active' to 'no longer active') of the East Eifel Volcanic Field. Precariously the Laacher See is located closely to the densely populated agglomerations of Cologne (NE, distance: 45 km) and the former capital Bonn (NE: 35km), as well as Koblenz (E: 24km) and the Rhine river. Apart from that, the towns of Andernach (E: 8km ± 30 000 inhabitants) and Mayen (SW: 11km ±20 000 inhabitants) and many smaller towns and villages are nearby due to economic reasons. The number of people affected by a possible eruption easily exceeds two million people considering the range as prime measurement. The underlying danger, as projected in a simulation presented by Prof. Schminke, is a lava stream running down the Brohltal valley

  7. The Variable Climate Impact of Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Graf, H.

    2011-12-01

    The main effect of big volcanic eruptions in the climate system is due to their efficient transport of condensable gases and their precursors into the stratosphere. There the formation of aerosols leads to effects on atmospheric radiation transfer inducing a reduction of incoming solar radiation by reflection (i.e. cooling of the Earth surface) and absorption of near infrared radiation (i.e. heating) in the aerosol laden layers. In the talk processes determining the climate effect of an eruption will be illustrated by examples, mainly from numerical modelling. The amount of gases released from a magma during an eruption and the efficiency of their transport into very high altitudes depends on the geological setting (magma type) and eruption style. While mid-sized eruption plumes of Plinian style quickly can develop buoyancy by entrainment of ambient air, very large eruptions with high magma flux rates often tend to collapsing plumes and co-ignimbrite style. These cover much bigger areas and are less efficient in entraining ambient air. Vertical transport in these plumes is chaotic and less efficient, leading to lower neutral buoyancy height and less gas and particles reaching high stratospheric altitudes. Explosive energy and amount of released condensable gases are not the only determinants for the climatic effect of an eruption. The effect on shortwave radiation is not linear with the amount of aerosols formed since according to the Lambert-Beer Law atmospheric optical depth reaches a saturation limit with increased absorber concentration. In addition, if more condensable gas is available for aerosol growth, particles become larger and this affects their optical properties to less reflection and more absorption. Larger particles settle out faster, thus reducing the life time of the aerosol disturbance. Especially for big tropical eruptions the strong heating of the stratosphere in low latitudes leads to changes in atmospheric wave propagation by strengthened

  8. SO2 flux and the thermal power of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Henley, Richard W.; Hughes, Graham O.

    2016-09-01

    A description of the dynamics, chemistry and energetics governing a volcanic system can be greatly simplified if the expansion of magmatic gas can be assumed to be adiabatic as it rises towards the surface. The conditions under which this assumption is valid are clarified by analysis of the transfer of thermal energy into the low conductivity wallrocks traversed by fractures and vents from a gas phase expanding over a range of mass flux rates. Adiabatic behavior is predicted to be approached typically within a month after perturbations in the release of source gas have stabilized, this timescale being dependent upon only the characteristic length scale on which the host rock is fractured and the thermal diffusivity of the rock. This analysis then enables the thermal energy transport due to gas release from volcanoes to be evaluated using observations of SO2 flux with reference values for the H2O:SO2 ratio of volcanic gas mixtures discharging through high temperature fumaroles in arc and mantle-related volcanic systems. Thermal power estimates for gas discharge are 101.8 to 104.1 MWH during quiescent, continuous degassing of arc volcanoes and 103.7 to 107.3 MWH for their eruptive stages, the higher value being the Plinean Pinatubo eruption in 1991. Fewer data are available for quiescent stage mantle-related volcanoes (Kilauea 102.1 MWH) but for eruptive events power estimates range from 102.8 MWH to 105.5 MWH. These estimates of thermal power and mass of gas discharges are commensurate with power estimates based on the total mass of gas ejected during eruptions. The sustained discharge of volcanic gas during quiescent and short-lived eruptive stages can be related to the hydrodynamic structure of volcanic systems with large scale gaseous mass transfer from deep in the crust coupled with episodes of high level intrusive activity and gas release.

  9. Assessing the volcanic hazard for Rome: 40Ar/39Ar and In-SAR constraints on the most recent eruptive activity and present-day uplift at Colli Albani Volcanic District

    NASA Astrophysics Data System (ADS)

    Marra, F.; Gaeta, M.; Giaccio, B.; Jicha, B. R.; Palladino, D. M.; Polcari, M.; Sottili, G.; Taddeucci, J.; Florindo, F.; Stramondo, S.

    2016-07-01

    We present new 40Ar/39Ar data which allow us to refine the recurrence time for the most recent eruptive activity occurred at Colli Albani Volcanic District (CAVD) and constrain its geographic area. Time elapsed since the last eruption (36 kyr) overruns the recurrence time (31 kyr) in the last 100 kyr. New interferometric synthetic aperture radar data, covering the years 1993-2010, reveal ongoing inflation with maximum uplift rates (>2 mm/yr) in the area hosting the most recent (<200 ka) vents, suggesting that the observed uplift might be caused by magma injection within the youngest plumbing system. Finally, we frame the present deformation within the structural pattern of the area of Rome, characterized by 50 m of regional uplift since 200 ka and by geologic evidence for a recent (<2000 years) switch of the local stress-field, highlighting that the precursors of a new phase of volcanic activity are likely occurring at the CAVD.

  10. Sequences and clusterings of significant volcanic eruptions in convergent plate margins during 1900 1980

    NASA Astrophysics Data System (ADS)

    Papadopoulos, G. A.

    1987-07-01

    Magmatic eruptions which lasted at least 15 days and had a Volcanic Explosivity Index ⩾ 1, are defined as significant volcanic eruptions. Data concerning significant eruptions which occurred from 1900 to 1980 show that in seventeen regions of plate convergence which were examined there is a similar time-evolution pattern of the volcanism, namely, periods of frequent volcanic activity with significant eruptions in at least one volcano (usually lasting less than 15 years) alternating with intervals of quiescence lasting from 4.5 to 20 years. Empirical criteria have been applied to classify ordinary periods, sequences, and clusterings of significant eruptions. Taking into account the date of the first eruption on all the volcanoes of a given period of frequent volcanic activity, then, in seven sequences or clusterings occurring in several regions, one may observe a systematic migration of the volcanism along the arc (e.g. in Lesser Sunda-Banda Sea Islands during 1963-1974). A clear positive correlation between the delay-time of the eruptions and the distance of the corresponding volcanoes from the first erupted volcano has been found. It is suggested that large-scale, long-term physical processes in the earth's interior may be responsible for the volcanic activity-volcanic quiescence pattern in plate convergence regions.

  11. Burst conditions of explosive volcanic eruptions recorded on microbarographs

    USGS Publications Warehouse

    Morrissey, M.M.; Chouet, B.A.

    1997-01-01

    Explosive volcanic eruptions generate pressure disturbances in the atmosphere that propagate away either as acoustic or as shock waves, depending on the explosivity of the eruption. Both types of waves are recorded on microbarographs as 1- to 0.1-hertz N-shaped signals followed by a longer period coda. These waveforms can be used to estimate burst pressures end gas concentrations in explosive volcanic eruptions and provide estimates of eruption magnitudes.

  12. 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.

  13. A probabilistic approach to determine volcanic eruption centres of degraded volcanic edifices

    NASA Astrophysics Data System (ADS)

    Székely, B.; Karátson, D.

    2009-04-01

    It is often a difficult problem to determine the position of original eruption centres of degraded volcanic edifices. Beside of the destructive processes acting during the volcanic activity, subsequent erosion, mass movements and tectonic motions modify the spatial distribution of the volcanic features. The observations including dipping strata, clast orientations, lava flows, etc. made on the present surface are therefore biased by the post-eruptive processes making the reconstruction of the original volcanic pattern problematic. The different types of observations and their various error levels complicate the problem further. We propose a probabilistic approach to evaluate the different types of observations. Each observation type or even each observation may have their own error bars which can be taken into account in this scheme. The only assumption is that it is possible to determine the relative direction of the original volcanic centre based on the specific observation within a given angular accuracy. In our scheme a spatial probability density function (PDF) is assigned to each observation and the weighted sum of these PDFs results in a map. This integrated PDF map then can be evaluated to determine one or multiple eruption centres. In case of multiple centres further decision can be made on whether the various centres are only virtual, caused by subsequent tectonism or, on the contrary, the original setting had several eruption vents. This decision can be made on targeted grouping of PDFs of different types of observations or spatial selection. The resulting compound PDF maps may outline individual centres.

  14. Incorporating the eruptive history in a stochastic model for volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark

    2008-08-01

    We show how a stochastic version of a general load-and-discharge model for volcanic eruptions can be implemented. The model tracks the history of the volcano through a quantity proportional to stored magma volume. Thus large eruptions can influence the activity rate for a considerable time following, rather than only the next repose as in the time-predictable model. The model can be fitted to data using point-process methods. Applied to flank eruptions of Mount Etna, it exhibits possible long-term quasi-cyclic behavior, and to Mauna Loa, a long-term decrease in activity. An extension to multiple interacting sources is outlined, which may be different eruption styles or locations, or different volcanoes. This can be used to identify an 'average interaction' between the sources. We find significant evidence that summit eruptions of Mount Etna are dependent on preceding flank eruptions, with both flank and summit eruptions being triggered by the other type. Fitted to Mauna Loa and Kilauea, the model had a marginally significant relationship between eruptions of Mauna Loa and Kilauea, consistent with the invasion of the latter's plumbing system by magma from the former.

  15. Complex interaction between Strombolian and phreatomagmatic eruptions in the Quaternary monogenetic volcanism of the Catalan Volcanic Zone (NE of Spain)

    NASA Astrophysics Data System (ADS)

    Martí, Joan; Planagumà, Llorenç; Geyer, Adelina; Canal, Esther; Pedrazzi, Dario

    2011-04-01

    The Catalan Volcanic Zone (CVZ), at the NE of the Iberian peninsula, is one of the Quaternary alkaline volcanic provinces of the European rifts system. The CVZ has been active during the last 12 Ma. Despite the fact that this volcanism is significant in extension and volume, and that eruptions have also occurred in Holocene times, it is mostly unknown compared to the contemporaneous alkaline volcanism in other parts of Western and Central Europe. Volcanism younger than 0.5 Ma is mostly concentrated in an area of about 100 km 2 located between the main cities of Olot and Girona. This basaltic volcanic field comprises more than 50 monogenetic cones including scoria cones, lava flows, tuff rings, and maars. Magmatic eruptions range from Hawaiian to violent Strombolian. Phreatomagmatism is also common and has contributed to the construction of more than a half of these volcanic edifices, frequently associated with the Strombolian activity but also independently, giving rise to a large variety of eruptive sequences. We describe the main characteristics of this volcanism and analyse in particular the successions of deposits that form some of these volcanoes and discuss the potential causes of such a wide diversity of eruptive sequences. We find that the main cause of such complex eruptive behaviour resides in the stratigraphic, structural and hydrogeological characteristics of the substrate above which the volcanoes were emplaced, rather than on the compositional characteristics of the erupting magma, as they do not show significant variations among the different volcanoes studied.

  16. Echo-resonance and hydraulic perturbations in magma cavities: application to the volcanic tremor of Etna (Italy) in relation to its eruptive activity

    NASA Astrophysics Data System (ADS)

    Montalto, A.; Longo, V.; Patanè, G.

    1995-08-01

    A study is presented of spectral features of volcanic tremor recorded at Mount Etna (Sicily, Italy) following the methods of analysis suggested by the resonant scattering formalism of Gaunaurd and Überall (1978, 1979a, 1979b) and the model for hydraulic origin of Seidl et al. (1981). The periods investigated include summit and flank eruptions that occurred between 1984 and 1993. Recordings from a permanent station located near the top of the volcano were used, and the temporal patterns associated with (a) the average spacing (bar Δ ) between consecutive spectral peaks in the frequency range 1 6 Hz, (b) the spectral shape and (c) the overall spectral amplitude were analyzed. bar Δ values are thought to depend on the physical properties of magma, such as its density, which, in turn, is controlled by the degree of gas exsolution. Variations in the spectral shape are tentatively attributed to changes in the geometrical scattering from the boundary of resonant conduits and magma batches. Finally, the overall amplitude at the station should essentially reflect the state of turbulence of magma within the superficial ascending path. A limit in the application of the resonant scattering formalism to the study of volcanic tremor is given by the fact that the fundamental modes and integer harmonics are difficult to identify in the frequency spectra, as tremor sources are likely within cavities of very complex geometry, rather than in spherical or cylindrical chambers, as expected by theory. This study gives evidence of some correlations between the analyzed temporal patterns and the major events in the volcanic activity, related to both lava flow and explosions at the summit vents. In particular, relatively high values of bar Δ have been attained during the SE crater eruption of 1984, the complex eruptive phases of September October 1989 and the 1991 1993 flank eruption, suggesting the presence of a relatively dense magma for all of these events. Conversely, very low

  17. [Effects of volcanic eruptions on environment and health].

    PubMed

    Zuskin, Eugenija; Mustajbegović, Jadranka; Doko Jelinić, Jagoda; Pucarin-Cvetković, Jasna; Milosević, Milan

    2007-12-01

    Volcanoes pose a threat to almost half a billion people; today there are approximately 500 active volcanoes on Earth, and every year there are 10 to 40 volcanic eruptions. Volcanic eruptions produce hazardous effects for the environment, climate, and the health of the exposed persons, and are associated with the deterioration of social and economic conditions. Along with magma and steam (H2O), the following gases surface in the environment: carbon dioxide (CO2) and sulphur dioxide (SO2), carbon monoxide (CO), hydrogen sulphide (H2S), carbon sulphide (CS), carbon disulfide (CS2), hydrogen chloride (HCl), hydrogen (H2), methane (CH4), hydrogen fluoride (HF), hydrogen bromide (HBr) and various organic compounds, as well as heavy metals (mercury, lead, gold).Their unfavourable effects depend on the distance from a volcano, on magma viscosity, and on gas concentrations. The hazards closer to the volcano include pyroclastic flows, flows of mud, gases and steam, earthquakes, blasts of air, and tsunamis. Among the hazards in distant areas are the effects of toxic volcanic ashes and problems of the respiratory system, eyes and skin, as well as psychological effects, injuries, transport and communication problems, waste disposal and water supplies issues, collapse of buildings and power outage. Further effects are the deterioration of water quality, fewer periods of rain, crop damages, and the destruction of vegetation. During volcanic eruptions and their immediate aftermath, increased respiratory system morbidity has been observed as well as mortality among those affected by volcanic eruptions. Unfavourable health effects could partly be prevented by timely application of safety measures.

  18. [Effects of volcanic eruptions on environment and health].

    PubMed

    Zuskin, Eugenija; Mustajbegović, Jadranka; Doko Jelinić, Jagoda; Pucarin-Cvetković, Jasna; Milosević, Milan

    2007-12-01

    Volcanoes pose a threat to almost half a billion people; today there are approximately 500 active volcanoes on Earth, and every year there are 10 to 40 volcanic eruptions. Volcanic eruptions produce hazardous effects for the environment, climate, and the health of the exposed persons, and are associated with the deterioration of social and economic conditions. Along with magma and steam (H2O), the following gases surface in the environment: carbon dioxide (CO2) and sulphur dioxide (SO2), carbon monoxide (CO), hydrogen sulphide (H2S), carbon sulphide (CS), carbon disulfide (CS2), hydrogen chloride (HCl), hydrogen (H2), methane (CH4), hydrogen fluoride (HF), hydrogen bromide (HBr) and various organic compounds, as well as heavy metals (mercury, lead, gold).Their unfavourable effects depend on the distance from a volcano, on magma viscosity, and on gas concentrations. The hazards closer to the volcano include pyroclastic flows, flows of mud, gases and steam, earthquakes, blasts of air, and tsunamis. Among the hazards in distant areas are the effects of toxic volcanic ashes and problems of the respiratory system, eyes and skin, as well as psychological effects, injuries, transport and communication problems, waste disposal and water supplies issues, collapse of buildings and power outage. Further effects are the deterioration of water quality, fewer periods of rain, crop damages, and the destruction of vegetation. During volcanic eruptions and their immediate aftermath, increased respiratory system morbidity has been observed as well as mortality among those affected by volcanic eruptions. Unfavourable health effects could partly be prevented by timely application of safety measures. PMID:18063533

  19. On an Unified Scaling Law for Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Cannavo, F.; Nunnari, G.

    2014-12-01

    Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At the present, both analytical and numerical models are unable to include all the possible dynamics involved into eruptions. On the other hand, the knowledge of eruption duration can be a key factor for natural hazard estimation. In this work, analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions can be described by a unique universal distribution which fully governs eruption duration dynamics. In particular, after the well-known results proposed in literature concerning the seismicity (i.e. the Gutenberg-Richter law), we present an Earth-wise power-law distribution of durations of volcanic eruptions that holds from worldwide to local scales, for different volcanic environments and for all the considered eruption types.

  20. Forecasting the duration of volcanic eruptions: an empirical probabilistic model

    NASA Astrophysics Data System (ADS)

    Gunn, L. S.; Blake, S.; Jones, M. C.; Rymer, H.

    2014-01-01

    The ability to forecast future volcanic eruption durations would greatly benefit emergency response planning prior to and during a volcanic crises. This paper introduces a probabilistic model to forecast the duration of future and on-going eruptions. The model fits theoretical distributions to observed duration data and relies on past eruptions being a good indicator of future activity. A dataset of historical Mt. Etna flank eruptions is presented and used to demonstrate the model. The data have been compiled through critical examination of existing literature along with careful consideration of uncertainties on reported eruption start and end dates between the years 1300 AD and 2010. Data following 1600 is considered to be reliable and free of reporting biases. The distribution of eruption duration between the years 1600 and 1669 is found to be statistically different from that following it and the forecasting model is run on two datasets of Mt. Etna flank eruption durations: 1600-2010 and 1670-2010. Each dataset is modelled using a log-logistic distribution with parameter values found by maximum likelihood estimation. Survivor function statistics are applied to the model distributions to forecast (a) the probability of an eruption exceeding a given duration, (b) the probability of an eruption that has already lasted a particular number of days exceeding a given total duration and (c) the duration with a given probability of being exceeded. Results show that excluding the 1600-1670 data has little effect on the forecasting model result, especially where short durations are involved. By assigning the terms `likely' and `unlikely' to probabilities of 66 % or more and 33 % or less, respectively, the forecasting model based on the 1600-2010 dataset indicates that a future flank eruption on Mt. Etna would be likely to exceed 20 days (± 7 days) but unlikely to exceed 86 days (± 29 days). This approach can easily be adapted for use on other highly active, well

  1. A lattice gas cellular automaton approach to model volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Sanchez, L.; Shcherbakov, R.

    2011-12-01

    Volcanic eruptions are the result of complex mechanisms that operate in a magma chamber within the crust. In a previous study, we showed that the dynamics of eruptions on Earth are the same and are quite independent of the location and type of volcanism. The goal of this study is to test the universality of volcanism by designing a simple, general model to simulate processes occurring within a magma chamber. We aim at reproducing the threshold behavior that operates in the magma chamber when pressure increase leads to an eruption. To simulate volcanic eruptions, we propose to use a lattice gas cellular automata (LGCA), which have been proven efficient to simulate fluid flow behavior. This type cellular automaton is a discrete dynamical model in space and time, where the fluid is represented at the microscopic level by discrete particles. We start with the simplest LGCA: the 2-dimensional HPP model (proposed in 1973 by Hardy, de Pazzis and Pomeau), which consists of a square lattice where particles interact with one another mimicking the fluid flow and conserving mass and momentum. We also consider the model on a hexagonal lattice to take anisotropy into account. In this model, magma propagates through a heterogeneous medium, and deformation and fracturing occurs on the walls of the chamber up until a pressure threshold is reached and an eruption or a cascade of eruptions occur. We record the size of each event and the number of time steps between consecutive events (or interevent time). The model simulation results for a large number of realizations are compared with observed data. The observations come from eruption records of 13 individual volcanoes located around the world as well as 11 groups of volcanoes located in various regions surrounded by different tectonic settings. From these, we computed the frequency-size distribution of eruptions and the interevent time distributions for a large number of active volcanoes on Earth. This model allows us to study a

  2. 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.

  3. The mechanism of volcanic eruptions (a steady state approach)

    NASA Astrophysics Data System (ADS)

    Slezin, Yu. B.

    2003-03-01

    A theory of a volcanic eruption as a steady magma flow from a magma chamber to the surface is described. Magma is considered as a two-component two-phase medium and magma flow is steady, one-dimensional and isothermal. Mass and momentum exchange between condensed and gaseous phases is assumed to be in equilibrium with nucleation of bubbles as a fast process at small oversaturations. Three basic flow structures in a conduit are recognized and three resulting types of eruption are described. (1) In the discrete gas separation (DGS) flow, melt with discrete gas bubbles erupts. This type includes lava eruptions and Strombolian activity. (2) In the dispersion regime there is continuous eruption of a gas-pyroclastic suspension. Catastrophic explosive eruptions are included in this type. (3) Here a partly destroyed foam is erupted with permeable structure that allows gas escape. Near the surface this structure evolves with an increase in permeability and a decrease in the total porosity. This type corresponds to lava dome extrusions. A criterion dividing DGS flow from the other two regimes is obtained: Di= Uηn1/3a/ c0, where U is the magma ascent velocity, η is magma viscosity, n is number of bubble nuclei in a unit mass of magma, a is the solubility coefficient for volatiles in magma and c0 is the volatile content. The boundary between the dispersion regime and the partly destroyed foam regime depends on U, c0 and particle size d p. For the dispersion regime the basic governing parameters are: magma chamber depth H, conduit conductivity σ= b2/ η ( b is the characteristic cross-dimension of the conduit), and excess pressure in the magma chamber. Instability of the dispersion regime is investigated numerically. The dependence of magma discharge rate on the governing parameters is described as a combination of equilibrium surfaces with cusp catastrophes. Magma chamber depth is a 'splitting' parameter in most cusps and controls the existence of unstable magma flow with

  4. Submarine Volcanic Eruptions and Potential Analogs for Venus

    NASA Technical Reports Server (NTRS)

    Wilson, L.; Mouginismark, P. J.; Fryer, P.; Gaddis, L. R.

    1985-01-01

    As part of an analysis program to better understand the diversity of volcanic processes on the terrestrial planets, an investigation of the volcanic landforms which exist on the Earth's ocean floor was initiated. In part, this analysis is focused toward gaining a better understanding of submarine volcanic landforms in their own right, but also it is hoped that these features may show similarities to volcanic landforms on Venus, due to the high ambient water (Earth) and atmospheric (Venus) pressures. A series of numerical modelling experiments was performed to investigate the relative importance of such attributes as water pressure and temperature on the eruption process, and to determine the rate of cooling and emplacement of lava flows in the submarine environment. Investigations to date show that the confining water pressure and the buoyancy effects of the surrounding water significantly affect the styles of volcanism on the ocean floor. In the case of Venusian volcanism, confining pressures will not be as great as that found at the ocean's abyssal plains, but nevertheless the general trend toward reducing magma vesiculation will hold true for Venus as well as the ocean floor. Furthermore, other analogs may also be found between submarine volcanism and Venusian activity.

  5. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    NASA Astrophysics Data System (ADS)

    Pyle, David M.

    2012-09-01

    Understanding of volcanic activity and its impacts on the atmosphere has evolved in discrete steps, associated with defining eruptions. The eruption of Krakatau, Indonesia, in August 1883 was the first whose global reach was recorded through observations of atmospheric phenomena around the world (Symons 1888). The rapid equatorial spread of Krakatau's ash cloud revealed new details of atmospheric circulation, while the vivid twilights and other optical phenomena were soon causally linked to the effects of particles and gases released from the volcano (e.g. Stothers 1996, Schroder 1999, Hamilton 2012). Later, eruptions of Agung, Bali (1963), El Chichón, Mexico (1982) and Pinatubo, Philippines (1991) led to a fuller understanding of how volcanic SO2 is transformed to a long-lived stratospheric sulfate aerosol, and its consequences (e.g. Meinel and Meinel 1967, Rampino and Self 1982, Hoffman and Rosen 1983, Bekki and Pyle 1994, McCormick et al 1995). While our ability to track the dispersal of volcanic emissions has been transformed since Pinatubo, with the launch of fleets of Earth-observing satellites (e.g. NASA's A-Train; ESA's MetOp) and burgeoning networks of ground-based remote-sensing instruments (e.g. lidar and sun-photometers; infrasound and lightning detection systems), there have been relatively few significant eruptions. Thus, there have been limited opportunities to test emerging hypotheses including, for example, the vexed question of the role of 'smaller' explosive eruptions in perturbations of the atmosphere—those that may just be large enough to reach the stratosphere (of size 'VEI 3', Newhall and Self 1982, Pyle 2000). Geological evidence, from ice-cores and historical eruptions, suggests that small explosive volcanic eruptions with the potential to transport material into the stratosphere should be frequent (5-10 per decade), and responsible for a significant proportion of the long-term time-averaged flux of volcanic sulfur into the stratosphere

  6. When do Volcanic Eruptions make Lightning? Observations from Sakurajima, Japan

    NASA Astrophysics Data System (ADS)

    Behnke, S. A.; McNutt, S. R.; Thomas, R. J.; Smith, C. M.; Edens, H. E.; Van Eaton, A. R.; Cimarelli, C.; Cigala, V.; Michel, C. W.; Miki, D.; Iguchi, M.

    2015-12-01

    Previous radio frequency (RF) observations of volcanic lightning have revealed that electrical activity frequently occurs concurrent with the onset of an explosive volcanic event. Typically, a myriad of electrical impulses originating from directly above the vent are observed first and the ensemble has durations of several seconds. The impulses are distinct from those produced by typical types of thunderstorm lightning, and have earned the moniker "continuous RF" due to their high rate and long-lasting nature . Several seconds after the onset of these impulses, small (100s of meters to several kilometers) lightning discharges occur in the plume and near the vent, and have electrical signatures similar to typical thunderstorm lightning. In eruptions with plume heights reaching 8-10 km or more, large scale (10s of kilometers) lightning discharges are observed throughout the plume several minutes after the onset of an explosive event.In May 2015, a campaign began to study the various types of small-scale electrical activity, including continuous RF, during explosive eruptions of Sakurajima volcano in Kyushu, Japan. The volcano was instrumented with two seismometers, two infrasound arrays, a high sensitivity video camera, an infrared camera, two high speed video cameras, still cameras, a 10-station Lightning Mapping Array, slow and fast electric field change sensors, and a broadband very high frequency (VHF) antenna. With these instruments, a robust data set of both the volcanic activity and electrical activity was collected. The preliminary data have revealed brief (1-2 seconds) bursts of continuous RF simultaneous with the onset of the more energetic explosions. Occurrence of continuous RF may be linked to mass eruption rate, explosivity, or grain size. Due to its unique nature, detection of continuous RF is an unambiguous indicator of explosive volcanic activity and is therefore useful for real-time volcano monitoring.

  7. Age, distance, and geochemical evolution within a monogenetic volcanic field: Analyzing patterns in the Auckland Volcanic Field eruption sequence

    NASA Astrophysics Data System (ADS)

    Corvec, Nicolas Le; Bebbington, Mark S.; Lindsay, Jan M.; McGee, Lucy E.

    2013-09-01

    The Auckland Volcanic Field (AVF) is a young active monogenetic basaltic field, which contains ˜50 volcanoes scattered across the Auckland metropolitan area. Understanding the temporal, spatial, and chemical evolution of the AVF during the last c.a. 250 ka is crucial in order to forecast a future eruption. Recent studies have provided new age constraints and potential temporal sequences of the past eruptions within the AVF. We use this information to study how the spatial distribution of the volcanic centers evolves with time, and how the chemical composition of the erupted magmas evolves with time and space. We seek to develop a methodology which compares successive eruptions to describe the link between geochemical and spatiotemporal evolution of volcanic centers within a monogenetic volcanic field. This methodology is tested with the present day data of the AVF. The Poisson nearest neighbor analysis shows that the spatial behavior of the field has been constant overtime, with the spatial distribution of the volcanic centers fitting the Poisson model within the significance levels. The results of the meta-analysis show the existence of correlations between the chemical composition of the erupted magmas and distance, volume, and time. The apparent randomness of the spatiotemporal evolution of the volcanic centers observed at the surface is probably influenced by the activity of the source. The methodology developed in this study can be used to identify possible relationships between composition trends and volume, time and/or distance to the behavior of the source, for successive eruptions of the AVF.

  8. Base surge in recent volcanic eruptions

    USGS Publications Warehouse

    Moore, J.G.

    1967-01-01

    A base surge, first identified at the Bikini thermonuclear undersea explosion, is a ring-shaped basal cloud that sweeps outward as a density flow from the base of a vertical explosion column. Base surges are also common in shallow underground test explosions and are formed by expanding gases which first vent vertically and then with continued expansion rush over the crater lip (represented by a large solitary wave in an underwater explosion), tear ejecta from it, and feed a gas-charged density flow, which is the surge cloud. This horizontally moving cloud commonly has an initial velocity of more than 50 meters per second and can carry clastic material many kilometers. Base surges are a common feature of many recent shallow, submarine and phreatic volcanic eruptions. They transport ash, mud, lapilli, and blocks with great velocity and commonly sandblast and knock down trees and houses, coat the blast side with mud, and deposit ejecta at distances beyond the limits of throw-out trajectories. Close to the eruption center, the base surge can erode radial channels and deposit material with dune-type bedding. ?? 1967 Stabilimento Tipografico Francesco Giannini & Figli.

  9. Forecasting volcanic eruptions: the narrow margin between eruption and intrusion

    NASA Astrophysics Data System (ADS)

    Steele, Alexander; Kilburn, Christopher; Wall, Richard; Charlton, Danielle

    2016-04-01

    Volcano-tectonic (VT) seismicity is one of the primary geophysical signals for monitoring volcanic unrest. It measures the brittle response of the crust to changes in stress and provides a natural proxy for gauging the stability of a pressurizing body of magma. Here we apply a new model of crustal extension to observations from the 2015 unrest of Cotopaxi, in Ecuador. The model agrees well with field data and is consistent with accelerating unrest during the pressurization and rupture of a vertically-extended magma source within the volcanic edifice. At andesitic-dacitic stratovolcanoes in subduction zones, unrest after long repose is often characterised by increases in VT event rate that change from an exponential to hyperbolic trend with time. This sequence was observed when renewed unrest was detected in April 2015 at Cotopaxi, following at least 73 years of repose. After about 80 days of elevated seismicity at an approximately steady rate, the numbers of VT events increased exponentially with time for c. 80 days, before increasing for c. 15 days along a faster, hyperbolic trend. Both trends were characterised by the same value of 2 for the ratio of maximum applied stress SF to tensile strength of the crust σT, consistent with the pressurization of an approximately vertical, cylindrical magma body. The hyperbolic trend indicated a potential rupture on 25 September. Rupture appears to have occurred on 21-22 September, when the VT rate rapidly decreased. However, no major eruption accompanied the change, suggesting that a near-surface intrusion occurred instead. Although the quantitative VT trends were consistent with the rupture of a magmatic body, they could not on their own distinguish between an eruptive or intrusive outcome. An outstanding goal remains to identify additional precursory characteristics for quantifying the probability that magma will reach the surface after escaping from a ruptured parent body. Data for this analysis were kindly made available

  10. Nano-volcanic Eruption of Silver

    PubMed Central

    Lin, Shih-kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-chen; Lin, Shih-guei; Suganuma, Katsuaki

    2016-01-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings. PMID:27703220

  11. Nano-volcanic Eruption of Silver

    NASA Astrophysics Data System (ADS)

    Lin, Shih-Kang; Nagao, Shijo; Yokoi, Emi; Oh, Chulmin; Zhang, Hao; Liu, Yu-Chen; Lin, Shih-Guei; Suganuma, Katsuaki

    2016-10-01

    Silver (Ag) is one of the seven metals of antiquity and an important engineering material in the electronic, medical, and chemical industries because of its unique noble and catalytic properties. Ag thin films are extensively used in modern electronics primarily because of their oxidation-resistance. Here we report a novel phenomenon of Ag nano-volcanic eruption that is caused by interactions between Ag and oxygen (O). It involves grain boundary liquation, the ejection of transient Ag-O fluids through grain boundaries, and the decomposition of Ag-O fluids into O2 gas and suspended Ag and Ag2O clusters. Subsequent coating with re-deposited Ag-O and the de-alloying of O yield a conformal amorphous Ag coating. Patterned Ag hillock arrays and direct Ag-to-Ag bonding can be formed by the homogenous crystallization of amorphous coatings. The Ag “nano-volcanic eruption” mechanism is elaborated, shedding light on a new mechanism of hillock formation and new applications of amorphous Ag coatings.

  12. Eruption probabilities for the Lassen Volcanic Center and regional volcanism, northern California, and probabilities for large explosive eruptions in the Cascade Range

    USGS Publications Warehouse

    Nathenson, Manuel; Clynne, Michael A.; Muffler, L.J. Patrick

    2012-01-01

    Chronologies for eruptive activity of the Lassen Volcanic Center and for eruptions from the regional mafic vents in the surrounding area of the Lassen segment of the Cascade Range are here used to estimate probabilities of future eruptions. For the regional mafic volcanism, the ages of many vents are known only within broad ranges, and two models are developed that should bracket the actual eruptive ages. These chronologies are used with exponential, Weibull, and mixed-exponential probability distributions to match the data for time intervals between eruptions. For the Lassen Volcanic Center, the probability of an eruption in the next year is 1.4x10-4 for the exponential distribution and 2.3x10-4 for the mixed exponential distribution. For the regional mafic vents, the exponential distribution gives a probability of an eruption in the next year of 6.5x10-4, but the mixed exponential distribution indicates that the current probability, 12,000 years after the last event, could be significantly lower. For the exponential distribution, the highest probability is for an eruption from a regional mafic vent. Data on areas and volumes of lava flows and domes of the Lassen Volcanic Center and of eruptions from the regional mafic vents provide constraints on the probable sizes of future eruptions. Probabilities of lava-flow coverage are similar for the Lassen Volcanic Center and for regional mafic vents, whereas the probable eruptive volumes for the mafic vents are generally smaller. Data have been compiled for large explosive eruptions (>≈ 5 km3 in deposit volume) in the Cascade Range during the past 1.2 m.y. in order to estimate probabilities of eruption. For erupted volumes >≈5 km3, the rate of occurrence since 13.6 ka is much higher than for the entire period, and we use these data to calculate the annual probability of a large eruption at 4.6x10-4. For erupted volumes ≥10 km3, the rate of occurrence has been reasonably constant from 630 ka to the present, giving

  13. The relationship between eruptive activity, flank collapse, and sea level at volcanic islands: A long-term (>1 Ma) record offshore Montserrat, Lesser Antilles

    NASA Astrophysics Data System (ADS)

    Coussens, Maya; Wall-Palmer, Deborah; Talling, Peter. J.; Watt, Sebastian. F. L.; Cassidy, Michael; Jutzeler, Martin; Clare, Michael A.; Hunt, James. E.; Manga, Michael; Gernon, Thomas. M.; Palmer, Martin. R.; Hatter, Stuart. J.; Boudon, Georges; Endo, Daisuke; Fujinawa, Akihiko; Hatfield, Robert; Hornbach, Matthew. J.; Ishizuka, Osamu; Kataoka, Kyoko; Le Friant, Anne; Maeno, Fukashi; McCanta, Molly; Stinton, Adam. J.

    2016-07-01

    Hole U1395B, drilled southeast of Montserrat during Integrated Ocean Drilling Program Expedition 340, provides a long (>1 Ma) and detailed record of eruptive and mass-wasting events (>130 discrete events). This record can be used to explore the temporal evolution in volcanic activity and landslides at an arc volcano. Analysis of tephra fall and volcaniclastic turbidite deposits in the drill cores reveals three heightened periods of volcanic activity on the island of Montserrat (˜930 to ˜900 ka, ˜810 to ˜760 ka, and ˜190 to ˜120 ka) that coincide with periods of increased volcano instability and mass-wasting. The youngest of these periods marks the peak in activity at the Soufrière Hills volcano. The largest flank collapse of this volcano (˜130 ka) occurred toward the end of this period, and two younger landslides also occurred during a period of relatively elevated volcanism. These three landslides represent the only large (>0.3 km3) flank collapses of the Soufrière Hills edifice, and their timing also coincides with periods of rapid sea level rise (>5 m/ka). Available age data from other island arc volcanoes suggest a general correlation between the timing of large landslides and periods of rapid sea level rise, but this is not observed for volcanoes in intraplate ocean settings. We thus infer that rapid sea level rise may modulate the timing of collapse at island arc volcanoes, but not in larger ocean-island settings.

  14. Particle-water heat transfer during explosive volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Woodcock, D. C.; Gilbert, J. S.; Lane, S. J.

    2012-10-01

    Thermal interaction between volcanic particles and water during explosive eruptions has been quantified using a numerical heat transfer model for spherical particles. The model couples intraparticle conduction with heat transfer from the particle surface by boiling water in order to explore heat loss with time for a range of particle diameters. The results are combined with estimates of particle settling times to provide insight into heat removal during eruption from samples of volcanic particles produced by explosive eruption. Heat removal is restricted by resistance to heat transfer from the volcanic particles with intraparticle thermal conduction important for large particles and surface cooling by boiling dominating for small particles. In most cases, volcanic particles approach thermal equilibrium with the surrounding fluid during an explosive eruption. Application of the results to a sample from the Gjálp 1996, Iceland eruption indicates that, relative to 0○C, 70-80% of the heat is transferred from the particles to boiling water during the settling time before burial in the stratigraphic succession. The implication is that, for subglacial explosive eruptions, much of the heat content of the magma is coupled into melting ice extremely rapidly. If all particles of the Gjálp 1996 deposit were cooled to the local boiling point by the end of the eruption then approximately 78% of the initial heat content was removed from the erupting magma during the eruption. This is consistent with calorimetric calculations based on volumes of ice melted during and after the eruption.

  15. Using Infrasound and Machine Learning for Monitoring Plinian Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Ham, F. M.; Iyengar, I.; Hambebo, B. M.; Garces, M. A.; Deaton, J.; Perttu, A.; Williams, B.

    2012-12-01

    Large plinian volcanic eruptions can inject a substantial amount of volcanic gas and ash into the stratosphere. This can present a severe hazard to commercial air traffic. A hazardous Icelandic volcanic ash-eruption was reported on April 14, 2010. This resulted in London's aviation authority to issue an alert that an ash plume was moving from an eruption in Iceland towards northwestern Europe. This eruption resulted in the closure of large areas of European airspace. Large plinian volcanic eruptions radiate infrasonic signals that can be detected by a global infrasound array network. To reduce potential hazards for commercial aviation from volcanic ash, these infrasound sensor arrays have been used to detect infrasonic signals released by sustained volcanic eruptions that can inject ash into the stratosphere at aircraft's cruising altitudes, typically in the order of 10km. A system that is capable of near, real-time eruption detection and discrimination of plinian eruptions from other natural phenomena that can produce infrasound with overlapping spectral content (0.01 to 0.1 Hz) is highly desirable to provide ash-monitoring for commercial aviation. In the initial study, cepstral features were extracted from plinian volcanic eruptions and mountain associated wave infrasound signals. These feature vectors were then used to train and test a two-module neural network classifier (radial basis function neural networks were used for each module). One module is dedicated to classifying plinian volcanic eruptions, the other mountain associated waves. Using an independent validation dataset, the classifier's correct classification rate was 91.5%. Then a different two-module neural network classifier was designed to discriminate between plinian volcanic eruptions and a collection of infrasound signals that are not-of-interest but have spectral content that overlaps with the volcano signals. One module is again dedicated to classifying plinian volcanic eruptions, however, in

  16. Explosive volcanism lessons learned from Mentos and soda eruptions

    NASA Astrophysics Data System (ADS)

    Wright, H. M.; Rust, A. C.; Cashman, K. V.

    2006-12-01

    When hard Mentos candies are dropped into a bottle of carbonated beverage, the resultant rapid CO2 exsolution and gas expansion causes an impressive soda `eruption'. We explore the ways in which this simple example can be used to demonstrate explosive volcanic processes. Through hands-on experiments, students can vary the type of candy, the type of beverage, and the shape of the vent (by making a hole in the cap of the soda bottle) to understand the processes that are influencing the height and duration of the eruption column. The activity can be tailored to demonstrate basic principles of gas exsolution and expansion for young students, but can also be extended to more complex principles of heterogeneous bubble nucleation and decreasing surface tension for college students. We present results from Mentos and soda experiments by a group of college freshman in the elementary education program (with no real science background). We compare students' resultant understanding of the similarities and differences between volcanic eruptions and the experiments with the results from a similar activity performed by a group of graduate geology students. The Mentos and soda reaction is dramatic. Video clips of people, young and old, trying this experiment across the world can be found on the world wide web. We suggest that the popularity of this demonstration be used to help teach fundamental concepts in both volcanology and scientific experimentation.

  17. Can Rock Deformation Experiments Help us to Forecast Volcanic Eruptions?

    NASA Astrophysics Data System (ADS)

    Smith, R.; Kilburn, C. R.; Sammonds, P. R.

    2009-05-01

    Volcanic eruption forecasting models show that the strength and mechanical properties of volcanic rocks are a primary control on the behaviour of volcanic systems, especially during the approach to eruptions. The progressive failure of these rocks, recorded as sequences of small volcano tectonic earthquakes, can lead to the formation of new magma pathways, allowing eruptions to begin at volcanoes that have not erupted in hundreds of years. Rates and patterns of these small earthquakes, which are typically located within a few km of the volcano summit, are monitored at many volcanoes and used to forecast eruptions. Models of crack growth and interaction have been used to constrain expected patterns in accelerating earthquake rates before the first eruption after a long repose interval. These deterministic models rely on laboratory mechanical data from volcanic rocks tested under the temperature and pressure conditions expected within and beneath a volcanic edifice. Here, we present data from high temperature uniaxial and triaxial deformation of andesite and dacite at temperatures of up to 1000°C, and under confining pressures of up to 50 MPa. These are typical rock types for volcanoes likely to erupt violently after hundreds of years of repose, where these forecasting models have previously been applied. The conditions tested cover the full range of temperatures and pressures expected within the upper 2-3 km of volcanic systems. The eruption forecasting model, with new constraints from this laboratory data, is applied to sequences of VT earthquakes before eruptions and to sequences of acoustic emissions before laboratory sample failure. Both types of data showed accelerating trends within the limits defined in the model, whilst sequences of earthquakes and acoustic emissions not resulting in eruption or sample failure exhibited accelerations outside the model limits. These results support the scaling of laboratory data to field scale and the use of laboratory data

  18. Modelling of Subglacial Volcanic and Geothermal Activity, during the 2014-15 Bárdarbunga-Holuhraun Eruption and Caldera Collapse

    NASA Astrophysics Data System (ADS)

    Reynolds, H. I.; Gudmundsson, M. T.; Hognadottir, T.

    2015-12-01

    Seismic unrest was observed within the subglacial caldera of Bárdarbunga on 16 August 2014, followed by seismicity tracing the path of a lateral dyke extending underneath the Vatnajökull glacier out to 45 km to the north east of the volcano. A short subaerial fissure eruption occurred at the site of the Holuhraun lavas, just north of the glacier edge on 29 August, before recommencing in earnest on 31 August with a large effusive eruption and accompanying slow caldera collapse, which lasted for approximately 6 months. The glacier surface around Bárdarbunga was monitored using aerial altimeter profiling. Several shallow depressions, known as ice cauldrons, formed around the caldera rim and on Dyngjujökull glacier above the dyke propagation path. The cauldrons range in volume from approximately 0.0003 km3 to 0.02 km3. Two types of melting were observed: high initial heat flux over a period of days which gradually disappears; and slower but more sustained melting rates. We present time series data of the development and evolution of these cauldrons, with estimates of the heat flux magnitudes involved.The nature of the heat source required to generate these cauldrons is not obvious. Two scenarios are explored: 1) small subglacial eruptions; or 2) increased geothermal activity induced by the dyke intrusion. We investigate these scenarios using numerical modelling, considering the surface heat flux produced, and timescales and spatial extent of associated surface anomalies. It is found that a magmatic intrusion into rocks where the groundwater is near the boiling point curve can cause rapid increase in geothermal activity, but even a shallow intrusion into a cold groundwater reservoir will have a muted thermal response. Thus, our results indicate that minor subglacial eruptions are the most plausible explanation for the observed rapid melting far from known geothermal areas. These results have implications for the interpretation of thermal signals observed at ice

  19. Using lightning observations as a volcanic eruption monitoring tool

    NASA Astrophysics Data System (ADS)

    Behnke, Sonja A.; McNutt, Stephen R.

    2014-08-01

    Lightning commonly occurs in the eruption columns produced by explosive volcanic eruptions. There are several different kinds of lightning detection instruments that could be employed to help monitor volcanoes, each with their own advantages and disadvantages. Very low frequency (VLF) instruments have the ability to detect lightning at long ranges but tend to have low sensitivity due to network geometry and typically can provide only the time and 2-D location of a cloud-to-ground return stroke or similar high-amplitude pulse produced by an intracloud discharge. Low frequency (LF) and medium frequency (MF) instruments typically have more sensitivity than a VLF network but can only be used for detection on a regional scale. Very high frequency (VHF) lightning mapping instruments also provide only regional coverage but detect all lightning within their range. During the 2009 eruption of Redoubt Volcano, Alaska, USA, each of these types of instruments detected lightning from Redoubt's ash plume. The VHF system consistently detected lightning before the other two during each distinct explosive event and also detected more lightning than the others, by one or two orders of magnitude. Lightning observations could be used to confirm, and in some cases, detect explosive volcanic activity. The rapid response provided by lightning monitoring is a valuable tool for fast identification of potentially hazardous ash clouds.

  20. Volcanic eruptions and research drilling in the Inyo Domes Chain

    SciTech Connect

    McConnell, V.S.; Eichelberger, J.C.

    1987-07-01

    This booklet is a non-technical guide for visitors to the Inyo Craters and Sandia drilling operation, covering kinds of volcanic eruptions, research drilling into volcanoes, and environmental aspects.

  1. IPLOR performance in detecting infrasound from volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Ghica, Daniela; Popa, Mihaela

    2016-04-01

    Plostina infrasound array (IPLOR) is located in the central part of Romania, in Vrancea region, its current configuration consisting of 6 elements equipped with Chaparral Physics sensors deployed over a 2.5 km aperture. The array detectability observed after processing of more than 6 years of data has shown that IPLOR is more effective in measuring mainly infrasound signals produced by natural and anthropogenic impulsive sources. This can be explained by the sensors' characteristics (frequency response, dynamic range) and the large aperture of array. Among the types of events observed with IPLOR, an emphasis can be given to the Mt. Etna volcanic eruptions as one of the powerful infrasound source recorded by the array. Located at about 1320 km distance from volcano, the array has proved efficient in observing both large and small eruptions. In case of the most large eruptive episodes occurred lately (April and October 2013, December 2015), long duration infrasonic signals were detected, the initial impulsive signature of the volcanic explosion being followed by a long train of irregular waves with smaller amplitudes and higher frequency, extended over periods ranging from 6 hours to more than three days (in December 2015). For the purpose of assessing the IPLOR performance in detecting Etna eruptions, the signal interactive analysis was performed using WinPMCC, CEA/DASE version of PMCC software. The infrasound detections obtained were plotted in function of back-azimuth, velocity and frequency, showing that the detectability is dependent both on the diurnal variations of the noise around the array (during the night the human activity diminishes) and on the seasonally dependent stratospheric winds (westward propagation during summer and eastward propagation during winter). In case of the Etna eruptive episodes detected by IPLOR, the back azimuth observed is in good agreement with the expected value (230o), i.e. an average value of 232±2o could be resolved. The

  2. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    NASA Astrophysics Data System (ADS)

    Pyle, David M.

    2012-09-01

    Understanding of volcanic activity and its impacts on the atmosphere has evolved in discrete steps, associated with defining eruptions. The eruption of Krakatau, Indonesia, in August 1883 was the first whose global reach was recorded through observations of atmospheric phenomena around the world (Symons 1888). The rapid equatorial spread of Krakatau's ash cloud revealed new details of atmospheric circulation, while the vivid twilights and other optical phenomena were soon causally linked to the effects of particles and gases released from the volcano (e.g. Stothers 1996, Schroder 1999, Hamilton 2012). Later, eruptions of Agung, Bali (1963), El Chichón, Mexico (1982) and Pinatubo, Philippines (1991) led to a fuller understanding of how volcanic SO2 is transformed to a long-lived stratospheric sulfate aerosol, and its consequences (e.g. Meinel and Meinel 1967, Rampino and Self 1982, Hoffman and Rosen 1983, Bekki and Pyle 1994, McCormick et al 1995). While our ability to track the dispersal of volcanic emissions has been transformed since Pinatubo, with the launch of fleets of Earth-observing satellites (e.g. NASA's A-Train; ESA's MetOp) and burgeoning networks of ground-based remote-sensing instruments (e.g. lidar and sun-photometers; infrasound and lightning detection systems), there have been relatively few significant eruptions. Thus, there have been limited opportunities to test emerging hypotheses including, for example, the vexed question of the role of 'smaller' explosive eruptions in perturbations of the atmosphere—those that may just be large enough to reach the stratosphere (of size 'VEI 3', Newhall and Self 1982, Pyle 2000). Geological evidence, from ice-cores and historical eruptions, suggests that small explosive volcanic eruptions with the potential to transport material into the stratosphere should be frequent (5-10 per decade), and responsible for a significant proportion of the long-term time-averaged flux of volcanic sulfur into the stratosphere

  3. Volcanic sulfur dioxide index and volcanic explosivity index inferred from eruptive volume of volcanoes in Jeju Island, Korea: application to volcanic hazard mitigation

    NASA Astrophysics Data System (ADS)

    Ko, Bokyun; Yun, Sung-Hyo

    2016-04-01

    Jeju Island located in the southwestern part of Korea Peninsula is a volcanic island composed of lavaflows, pyroclasts, and around 450 monogenetic volcanoes. The volcanic activity of the island commenced with phreatomagmatic eruptions under subaqueous condition ca. 1.8-2.0 Ma and lasted until ca. 1,000 year BP. For evaluating volcanic activity of the most recently erupted volcanoes with reported age, volcanic explosivity index (VEI) and volcanic sulfur dioxide index (VSI) of three volcanoes (Ilchulbong tuff cone, Songaksan tuff ring, and Biyangdo scoria cone) are inferred from their eruptive volumes. The quantity of eruptive materials such as tuff, lavaflow, scoria, and so on, is calculated using a model developed in Auckland Volcanic Field which has similar volcanic setting to the island. The eruptive volumes of them are 11,911,534 m3, 24,987,557 m3, and 9,652,025 m3, which correspond to VEI of 3, 3, and 2, respectively. According to the correlation between VEI and VSI, the average quantity of SO2 emission during an eruption with VEI of 3 is 2-8 × 103 kiloton considering that the island was formed under intraplate tectonic setting. Jeju Island was regarded as an extinct volcano, however, several studies have recently reported some volcanic eruption ages within 10,000 year BP owing to the development in age dating technique. Thus, the island is a dormant volcano potentially implying high probability to erupt again in the future. The volcanoes might have explosive eruptions (vulcanian to plinian) with the possibility that SO2 emitted by the eruption reaches stratosphere causing climate change due to backscattering incoming solar radiation, increase in cloud reflectivity, etc. Consequently, recommencement of volcanic eruption in the island is able to result in serious volcanic hazard and this study provides fundamental and important data for volcanic hazard mitigation of East Asia as well as the island. ACKNOWLEDGMENTS: This research was supported by a grant [MPSS

  4. On a Possible Unified Scaling Law for Volcanic Eruption Durations

    NASA Astrophysics Data System (ADS)

    Cannavò, Flavio; Nunnari, Giuseppe

    2016-03-01

    Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At present, due to the complexity of involved phenomena and to the lack of precise measurements, both analytical and numerical models are unable to simultaneously include the main processes involved in eruptions thus making forecasts of volcanic dynamics rather unreliable. On the other hand, accurate forecasts of some eruption parameters, such as the duration, could be a key factor in natural hazard estimation and mitigation. Analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions seems to be described by a universal distribution which characterizes eruption duration dynamics. In particular, this paper presents a plausible global power-law distribution of durations of volcanic eruptions that holds worldwide for different volcanic environments. We also introduce a new, simple and realistic pipe model that can follow the same found empirical distribution. Since the proposed model belongs to the family of the self-organized systems it may support the hypothesis that simple mechanisms can lead naturally to the emergent complexity in volcanic behaviour.

  5. On a Possible Unified Scaling Law for Volcanic Eruption Durations.

    PubMed

    Cannavò, Flavio; Nunnari, Giuseppe

    2016-03-01

    Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At present, due to the complexity of involved phenomena and to the lack of precise measurements, both analytical and numerical models are unable to simultaneously include the main processes involved in eruptions thus making forecasts of volcanic dynamics rather unreliable. On the other hand, accurate forecasts of some eruption parameters, such as the duration, could be a key factor in natural hazard estimation and mitigation. Analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions seems to be described by a universal distribution which characterizes eruption duration dynamics. In particular, this paper presents a plausible global power-law distribution of durations of volcanic eruptions that holds worldwide for different volcanic environments. We also introduce a new, simple and realistic pipe model that can follow the same found empirical distribution. Since the proposed model belongs to the family of the self-organized systems it may support the hypothesis that simple mechanisms can lead naturally to the emergent complexity in volcanic behaviour.

  6. Months between rejuvenation and volcanic eruption at Yellowstone caldera, Wyoming

    USGS Publications Warehouse

    Till, Christy B.; Vazquez, Jorge A.; Boyce, Jeremy W

    2015-01-01

    Rejuvenation of previously intruded silicic magma is an important process leading to effusive rhyolite, which is the most common product of volcanism at calderas with protracted histories of eruption and unrest such as Yellowstone, Long Valley, and Valles, USA. Although orders of magnitude smaller in volume than rare caldera-forming super-eruptions, these relatively frequent effusions of rhyolite are comparable to the largest eruptions of the 20th century and pose a considerable volcanic hazard. However, the physical pathway from rejuvenation to eruption of silicic magma is unclear particularly because the time between reheating of a subvolcanic intrusion and eruption is poorly quantified. This study uses geospeedometry of trace element profiles with nanometer resolution in sanidine crystals to reveal that Yellowstone’s most recent volcanic cycle began when remobilization of a near- or sub-solidus silicic magma occurred less than 10 months prior to eruption, following a 220,000 year period of volcanic repose. Our results reveal a geologically rapid timescale for rejuvenation and effusion of ~3 km3 of high-silica rhyolite lava even after protracted cooling of the subvolcanic system, which is consistent with recent physical modeling that predict a timescale of several years or less. Future renewal of rhyolitic volcanism at Yellowstone is likely to require an energetic intrusion of mafic or silicic magma into the shallow subvolcanic reservoir and could rapidly generate an eruptible rhyolite on timescales similar to those documented here.

  7. On a Possible Unified Scaling Law for Volcanic Eruption Durations.

    PubMed

    Cannavò, Flavio; Nunnari, Giuseppe

    2016-01-01

    Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At present, due to the complexity of involved phenomena and to the lack of precise measurements, both analytical and numerical models are unable to simultaneously include the main processes involved in eruptions thus making forecasts of volcanic dynamics rather unreliable. On the other hand, accurate forecasts of some eruption parameters, such as the duration, could be a key factor in natural hazard estimation and mitigation. Analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions seems to be described by a universal distribution which characterizes eruption duration dynamics. In particular, this paper presents a plausible global power-law distribution of durations of volcanic eruptions that holds worldwide for different volcanic environments. We also introduce a new, simple and realistic pipe model that can follow the same found empirical distribution. Since the proposed model belongs to the family of the self-organized systems it may support the hypothesis that simple mechanisms can lead naturally to the emergent complexity in volcanic behaviour. PMID:26926425

  8. On a Possible Unified Scaling Law for Volcanic Eruption Durations

    PubMed Central

    Cannavò, Flavio; Nunnari, Giuseppe

    2016-01-01

    Volcanoes constitute dissipative systems with many degrees of freedom. Their eruptions are the result of complex processes that involve interacting chemical-physical systems. At present, due to the complexity of involved phenomena and to the lack of precise measurements, both analytical and numerical models are unable to simultaneously include the main processes involved in eruptions thus making forecasts of volcanic dynamics rather unreliable. On the other hand, accurate forecasts of some eruption parameters, such as the duration, could be a key factor in natural hazard estimation and mitigation. Analyzing a large database with most of all the known volcanic eruptions, we have determined that the duration of eruptions seems to be described by a universal distribution which characterizes eruption duration dynamics. In particular, this paper presents a plausible global power-law distribution of durations of volcanic eruptions that holds worldwide for different volcanic environments. We also introduce a new, simple and realistic pipe model that can follow the same found empirical distribution. Since the proposed model belongs to the family of the self-organized systems it may support the hypothesis that simple mechanisms can lead naturally to the emergent complexity in volcanic behaviour. PMID:26926425

  9. Io. [theories concerning volcanic activity

    NASA Technical Reports Server (NTRS)

    Johnson, T. V.; Soderblom, L. A.

    1983-01-01

    A report on the continuing investigation of Io is presented. Gravitational resonance is discussed as the cause of Io's volcanism, and the volcanic activity is explained in terms of sulfur chemistry. Theories concerning the reasons for the two main types of volcanic eruptions on Io are advanced and correlated with geographical features of the satellite. The sulfur and silicate models of the calderas are presented, citing the strengths and weaknesses of each. Problems of the gravitational resonance theory of Io's heat source are then described. Finally, observations of Io planned for the Galileo mission are summarized.

  10. Characterizing Volcanic Eruptions on Venus: Some Realistic (?) Scenarios

    NASA Technical Reports Server (NTRS)

    Stofan, E. R.; Glaze, L. S.; Grinspoon, D. H.

    2011-01-01

    When Pioneer Venus arrived at Venus in 1978, it detected anomalously high concentrations of SO2 at the top of the troposphere, which subsequently declined over the next five years. This decline in SO2 was linked to some sort of dynamic process, possibly a volcanic eruption. Observations of SO2 variability have persisted since Pioneer Venus. More recently, scientists from the Venus Express mission announced that the SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) instrument had measured varying amounts of SO2 in the upper atmosphere; VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) measured no similar variations in the lower atmosphere (ESA, 4 April, 2008). In addition, Fegley and Prinn stated that venusian volcanoes must replenish SO2 to the atmosphere, or it would react with calcite and disappear within 1.9 my. Fegley and Tremain suggested an eruption rate on the order of approx 1 cubic km/year to maintain atmospheric SO2; Bullock and Grinspoon posit that volcanism must have occurred within the last 20-50 my to maintain the sulfuric acid/water clouds on Venus. The abundance of volcanic deposits on Venus and the likely thermal history of the planet suggest that it is still geologically active, although at rates lower than Earth. Current estimates of resurfacing rates range from approx 0.01 cubic km/yr to approx 2 cubic km/yr. Demonstrating definitively that Venus is still volcanically active, and at what rate, would help to constrain models of evolution of the surface and interior, and help to focus future exploration of Venus.

  11. 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.

  12. Systematic change in global patterns of streamflow following volcanic eruptions

    PubMed Central

    Iles, Carley E.; Hegerl, Gabriele C.

    2016-01-01

    Following large explosive volcanic eruptions precipitation decreases over much of the globe1–6, particularly in climatologically wet regions4,5. Stratospheric volcanic aerosols reflect sunlight, which reduces evaporation, whilst surface cooling stabilises the atmosphere and reduces its water-holding capacity7. Circulation changes modulate this global precipitation reduction on regional scales1,8–10. Despite the importance of rivers to people, it has been unclear whether volcanism causes detectable changes in streamflow given large natural variability. Here we analyse observational records of streamflow volume for fifty large rivers from around the world which cover between two and 6 major volcanic eruptions in the 20th and late 19th century. We find statistically significant reductions in flow following eruptions for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma amongst others. When data from neighbouring rivers are combined - based on the areas where climate models simulate either an increase or a decrease in precipitation following eruptions – a significant (p<0.1) decrease in streamflow following eruptions is detected in northern South American, central African and high-latitude Asian rivers, and on average across wet tropical and subtropical regions. We also detect a significant increase in southern South American and SW North American rivers. This suggests that future volcanic eruptions could substantially affect global water availability. PMID:27279897

  13. Smelters as Analogs for a Volcanic Eruption at Yucca Mountain

    SciTech Connect

    Ross, Benjamin

    2004-11-15

    The distribution of trace radionuclides in secondary metal smelters provides an analog for spent fuel released from packages during a volcanic eruption. The fraction of the inventory of a radionuclide that would be released into the air in a volcanic eruption is called the dust partitioning factor. In consequence analyses of a volcanic eruption at Yucca Mountain, a value of one has been used for this parameter for all elements. This value is too high for the refractory elements. Reducing the dust partitioning factor for refractory elements to a value equal to the fraction of the magma that becomes ash would still yield conservative estimates of how much radioactivity would be released in an eruption.

  14. On-line image analysis of the stromboli volcanic activity recorded by the surveillance camera helps the forecasting of the major eruptive events.

    NASA Astrophysics Data System (ADS)

    Cristaldi, A.; Coltelli, M.; Mangiagli, S.; Pecora, E.

    2003-04-01

    The typical activity of Stromboli consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes. However, the routine activity can be interrupted by more violent, paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. On average, 1-2 paroxysmal explosions occurred per year over the past century, but this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Using image analysis we seeks to identify any change of the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. From the day of the camera installation up to present 12 paroxysmal events and lava flows occurred. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. The plot of dissipated energy by each crater versus time shows a cyclic behavior with max and min of explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxysmal explosions recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at

  15. Eruptive modes and hiatus of volcanism at West Mata seamount, NE Lau basin: 1996-2012

    NASA Astrophysics Data System (ADS)

    Embley, Robert W.; Merle, Susan G.; Baker, Edward T.; Rubin, Kenneth H.; Lupton, John E.; Resing, Joseph A.; Dziak, Robert P.; Lilley, Marvin D.; Chadwick, William W.; Shank, T.; Greene, Ron; Walker, Sharon L.; Haxel, Joseph; Olson, Eric; Baumberger, Tamara

    2014-10-01

    present multiple lines of evidence for years to decade-long changes in the location and character of volcanic activity at West Mata seamount in the NE Lau basin over a 16 year period, and a hiatus in summit eruptions from early 2011 to at least September 2012. Boninite lava and pyroclasts were observed erupting from its summit in 2009, and hydroacoustic data from a succession of hydrophones moored nearby show near-continuous eruptive activity from January 2009 to early 2011. Successive differencing of seven multibeam bathymetric surveys of the volcano made in the 1996-2012 period reveals a pattern of extended constructional volcanism on the summit and northwest flank punctuated by eruptions along the volcano's WSW rift zone (WSWRZ). Away from the summit, the volumetrically largest eruption during the observational period occurred between May 2010 and November 2011 at ˜2920 m depth near the base of the WSWRZ. The (nearly) equally long ENE rift zone did not experience any volcanic activity during the 1996-2012 period. The cessation of summit volcanism recorded on the moored hydrophone was accompanied or followed by the formation of a small summit crater and a landslide on the eastern flank. Water column sensors, analysis of gas samples in the overlying hydrothermal plume and dives with a remotely operated vehicle in September 2012 confirmed that the summit eruption had ceased. Based on the historical eruption rates calculated using the bathymetric differencing technique, the volcano could be as young as several thousand years.

  16. Responses to, and the short and long-term impacts of, the 1957/1958 Capelinhos volcanic eruption and associated earthquake activity on Faial, Azores

    NASA Astrophysics Data System (ADS)

    Coutinho, Rui; Chester, David K.; Wallenstein, Nicolau; Duncan, Angus M.

    2010-10-01

    The 1957/58 Capelinhos eruption on Faial Island in the Azores is well known for being an excellent example of Surtseyan hydromagmatic volcanic activity. Less well known are the responses of the Portuguese authorities to the eruption and subsequent earthquake in May 1958, and the ways in which well-thought-out and generally effective recovery programmes were put in place. At the time Portugal was ruled by a dictatorship, the Estado Novo (New State). Only superficially similar to other fascist governments in Southern Europe, the Estado Novo collected huge amounts of data on the responses of the authorities to the disaster and their programmes of recovery, but never encouraged academic evaluation of policy, although it ensured that the scientific aspects of the eruption and earthquake were meticulously recorded and published. In this paper we remedy this situation by discussing the details of the immediate response to the emergency and the ways in which the island recovered in its aftermath. The study is based not only on archival sources and demographic and economic data, but also on detailed interviews with survivors some of whom were also decision makers. We argue that response, recovery and rehabilitation were generally highly successful and assess the lessons of the 1957/58 emergency which are relevant to future geophysical disasters in Faial and the wider Azores. Since the 1974 revolution Portugal has been a democratic state. We conclude that both the legislation and the civil defence infrastructure, necessary to achieve a similarly strong and successful response, are in place today.

  17. Impact of volcanic eruptions on the marine carbon cycle

    NASA Astrophysics Data System (ADS)

    Segschneider, Joachim; Ulrike, Niemeier; Martin, Wiesner; Claudia, Timmreck

    2010-05-01

    The impact of volcanic eruptions on the marine carbon cycle is investigated for the example of the Pinatubo eruption with model simulations of the distribution of the ash cloud and deposition on the ocean surface and the impact of the nutrient addition from ash leachates on the oceanic biological production and hence biological carbon pump. Natural variations of aerosols, especially due to large-magnitude volcanic eruptions, are recognized as a significant climate forcing, altering the Earth's radiation balance and thus tending to cause global temperature changes. While the impact of such events on climate and the terrestrial biosphere is relatively well documented, scientific knowledge of their effects on marine ecosystems and consequent feedbacks to the atmosphere is still very limited. In the deep sea, subaerial eruptive events of global significance are commonly recorded as widespread ash layers, which were often found to be associated with increased abundances of planktic organisms. This has led to the hypothesis that the influx of volcanic ash may provide an external nutrient source for primary production (in particular through iron fertilization) in ocean surface waters. Recent laboratory experiments have demonstrated that pristine volcanic ash indeed releases significant amounts of macronutrients and bioactive trace metals (including phosphate, iron and silica) adsorbed to the surface of the ash particles. The release of these components most likely has its largest impact in ocean regions where their availability is crucial for the growth of oceanic biomass, which are the high-nutrient but low-productivity (low-iron) areas in the Pacific and the Southern Ocean. These in turn are neighbored by most of those subaerially active volcanoes that are capable of ejecting huge amounts of aerosols into the high-velocity stratospheric wind fields. The dispersal and fallout of ash thus has a high potential to induce globally significant, transient net CO2 removal from

  18. What We Can Learn from the Next Large Volcanic Eruption

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2015-12-01

    The April 1982 eruption of El Chichón in México stimulated interest in the climate response to volcanic eruptions and produced very useful observations and modeling studies. The last large volcanic eruption, the June 15, 1991 eruption of Mt. Pinatubo in the Philippines, was the best observed eruption ever, and serves as a canonical example for studies of aerosol production and transport, climate response, and deposition on ice sheets. However, many aspects of both eruptions were poorly observed, climate model simulations of the response are imperfect, and new scientific issues, such as stratospheric sulfate geoengineering, raise new scientific questions that could be answered by better observations of the next large volcanic eruption. In this talk I will summarize what we know and do not know about large volcanic eruptions, and discuss new questions that can be addressed by being prepared for the next large eruption. These include: How and how fast will SO2 convert to sulfate aerosols? How will the aerosols grow? What will be the size distribution of the resulting sulfate aerosol particles? How will the aerosols be transported throughout the stratosphere? How much fine ash gets to the stratosphere, how long does it stay there, and what are its radiative and chemical impacts? How will temperatures change in the stratosphere as a result of the aerosol interactions with shortwave (particularly near IR) and longwave radiation? Are there large stratospheric water vapor changes associated with stratospheric aerosols? Is there an initial injection of water from the eruption? Is there ozone depletion from heterogeneous reactions on the stratospheric aerosols? As the aerosols leave the stratosphere, and as the aerosols affect the upper troposphere temperature and circulation, are there interactions with cirrus and other clouds?

  19. Monitoring El Hierro submarine volcanic eruption events with a submarine seismic array

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Molino, Erik; Lopez, Carmen

    2013-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2012 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. From the beginning of the eruption a geophone string was installed less than 2 km away from the new volcano, next to La Restinga village shore, to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. The analysis of the dataset using spectral techniques allows the characterization of the different phases of the eruption and the study of its dynamics. The correlation of the data analysis results with the observed sea surface activity (ash and lava emission and degassing) and also with the seismic activity recorded by the IGN field seismic monitoring system, allows the identification of different stages suggesting the existence of different signal sources during the volcanic eruption and also the posteruptive record of the degassing activity. The study shows that the high frequency capability of the geophone array allow the study of important features that cannot be registered by the standard seismic stations. The accumulative spectral amplitude show features related to eruptive changes.

  20. Global monsoon precipitation responses to large volcanic eruptions

    PubMed Central

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-01-01

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do. PMID:27063141

  1. Global monsoon precipitation responses to large volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-04-01

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.

  2. Global monsoon precipitation responses to large volcanic eruptions.

    PubMed

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-01-01

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do. PMID:27063141

  3. Global monsoon precipitation responses to large volcanic eruptions.

    PubMed

    Liu, Fei; Chai, Jing; Wang, Bin; Liu, Jian; Zhang, Xiao; Wang, Zhiyuan

    2016-04-11

    Climate variation of global monsoon (GM) precipitation involves both internal feedback and external forcing. Here, we focus on strong volcanic forcing since large eruptions are known to be a dominant mechanism in natural climate change. It is not known whether large volcanoes erupted at different latitudes have distinctive effects on the monsoon in the Northern Hemisphere (NH) and the Southern Hemisphere (SH). We address this issue using a 1500-year volcanic sensitivity simulation by the Community Earth System Model version 1.0 (CESM1). Volcanoes are classified into three types based on their meridional aerosol distributions: NH volcanoes, SH volcanoes and equatorial volcanoes. Using the model simulation, we discover that the GM precipitation in one hemisphere is enhanced significantly by the remote volcanic forcing occurring in the other hemisphere. This remote volcanic forcing-induced intensification is mainly through circulation change rather than moisture content change. In addition, the NH volcanic eruptions are more efficient in reducing the NH monsoon precipitation than the equatorial ones, and so do the SH eruptions in weakening the SH monsoon, because the equatorial eruptions, despite reducing moisture content, have weaker effects in weakening the off-equatorial monsoon circulation than the subtropical-extratropical volcanoes do.

  4. Climatic effects of atmospheric water vapor distribution through volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Yim, W. W.

    2011-12-01

    Volcanic eruptions play an important role in changing the water vapor distribution of the atmosphere. In comparison with the emission of carbon dioxide released during the consumption of fossil fuel, water vapor's role in climate change has been grossly underestimated. Studies made of modern volcanic eruptions, including satellite images and meteorological records, have revealed climatic effects in different parts of the globe through the migration of volcanic clouds, depending mainly on their timing, location, Volcanic Explosivity Index (VEI) and composition. The climatic effects of volcanic eruptions include: (1) Reduction in solar heating because of the particulates discharged. (2) Interference with the 'normal' atmospheric circulation and/or oceanic circulation. (3) The ash particles and aerosols provide condensation nuclei for water. (4) The transfer from the troposphere into the stratosphere of water vapor which act as a greenhouse gas more important than carbon dioxide. (5) Variability in regional rainfall including the occurrence of droughts, floods, landslides salinization and crop failures. (6) Anomalous regional wind and rain storms. (7) Acid rain. Selected volcanic eruptions will be used as examples to illustrate the different climatic effects.

  5. Volcanic hazards from Bezymianny- and Bandai-type eruptions

    USGS Publications Warehouse

    Siebert, L.; Glicken, H.; Ui, T.

    1987-01-01

    kilometers. When not confined by valley walls, avalanches can affect wide areas beyond the volcano's flanks. Tsunamis from debris avalanches at coastal volcanoes have caused more fatalities than have the landslides themselves or associated eruptions. The probable travel distance (L) of avalanches can be estimated by considering the potential vertical drop (H). Data from a catalog of around 200 debris avalanches indicates that the H/L rations for avalanches with volumes of 0.1-1 km3 average 0.13 and range 0.09-0.18; for avalanches exceeding 1 km3, H/L ratios average 0.09 and range 0.5-0.13. Large-scale deformation of the volcanic edefice and intense local seismicity precede many slope failures and can indicate the likely failure direction and orientation of potential lateral blasts. The nature and duration of precursory activity vary widely, and the timing of slope faliure greatly affects the type of associated eruption. Bandai-type eruptions are particularly difficult to anticipate because they typically climax suddenly without precursory eruptions and may be preceded by only short periods of seismicity. ?? 1987 Springer-Verlag.

  6. Probabilities of future VEI ≥ 2 eruptions at the Central American Volcanic Arc: a statistical perspective based on the past centuries' eruption record

    NASA Astrophysics Data System (ADS)

    Dzierma, Yvonne; Wehrmann, Heidi

    2014-10-01

    A probabilistic eruption forecast is provided for seven historically active volcanoes along the Central American Volcanic Arc (CAVA), as a pivotal empirical contribution to multi-disciplinary volcanic hazards assessment. The eruption probabilities are determined with a Kaplan-Meier estimator of survival functions, and parametric time series models are applied to describe the historical eruption records. Aside from the volcanoes that are currently in a state of eruptive activity (Santa María, Fuego, and Arenal), the highest probabilities for eruptions of VEI ≥ 2 occur at Concepción and Cerro Negro in Nicaragua, which are likely to erupt to 70-85 % within the next 10 years. Poás and Irazú in Costa Rica show a medium to high eruption probability, followed by San Miguel (El Salvador), Rincón de la Vieja (Costa Rica), and Izalco (El Salvador; 24 % within the next 10 years).

  7. Large, Moderate or Small? The Challenge of Measuring Mass Eruption Rates in Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, M. T.; Dürig, T.; Hognadottir, T.; Hoskuldsson, A.; Bjornsson, H.; Barsotti, S.; Petersen, G. N.; Thordarson, T.; Pedersen, G. B.; Riishuus, M. S.

    2015-12-01

    The potential impact of a volcanic eruption is highly dependent on its eruption rate. In explosive eruptions ash may pose an aviation hazard that can extend several thousand kilometers away from the volcano. Models of ash dispersion depend on estimates of the volcanic source, but such estimates are prone to high error margins. Recent explosive eruptions, including the 2010 eruption of Eyjafjallajökull in Iceland, have provided a wealth of data that can help in narrowing these error margins. Within the EU-funded FUTUREVOLC project, a multi-parameter system is currently under development, based on an array of ground and satellite-based sensors and models to estimate mass eruption rates in explosive eruptions in near-real time. Effusive eruptions are usually considered less of a hazard as lava flows travel slower than eruption clouds and affect smaller areas. However, major effusive eruptions can release large amounts of SO2 into the atmosphere, causing regional pollution. In very large effusive eruptions, hemispheric cooling and continent-scale pollution can occur, as happened in the Laki eruption in 1783 AD. The Bárdarbunga-Holuhraun eruption in 2014-15 was the largest effusive event in Iceland since Laki and at times caused high concentrations of SO2. As a result civil protection authorities had to issue warnings to the public. Harmful gas concentrations repeatedly persisted for many hours at a time in towns and villages at distances out to 100-150 km from the vents. As gas fluxes scale with lava fluxes, monitoring of eruption rates is therefore of major importance to constrain not only lava but also volcanic gas emissions. This requires repeated measurements of lava area and thickness. However, most mapping methods are problematic once lava flows become very large. Satellite data on thermal emissions from eruptions have been used with success to estimate eruption rate. SAR satellite data holds potential in delivering lava volume and eruption rate estimates

  8. Volcanic forcing of monsoonal precipitation variability in selected modern volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Yim, W. W.; Chan, J. C.

    2009-12-01

    An important characteristic of the monsoonal climate is the heavy summer precipitation and the winter drought brought about by the shift in wind circulation. For planet Earth to achieve greater future sustainability, a better understanding of precipitation variability in the densely populated monsoonal regions of the world is particularly critical. In the present study, three major modern tropical volcanic eruptions occurring over the past fifty years have been selected to investigate their influence on precipitation variability in the monsoonal region of southern China. The three eruptions are the February 1963 Agung eruption in Indonesia, the March 1982 El Chichón eruption in Mexico and the June 1991 Pinatubo eruption in the Philippines. Abnormally low annual precipitation was found in the southern China region during 1963 and 1991. Based on the annual precipitation at the Hong Kong Observatory Station, they were the driest and the tenth driest respectively since record began in 1884. In contrast, abnormally heavy precipitation was found in southern China in 1982 with the Hong Kong Observatory Station recording the second wettest year since record began. Based on the observed precipitation, near-field major volcanic eruptions located in the Indonesian-Pacific gateway may lead to abnormally dry conditions explained either by a shift and/or strengthening of predominantly offshore wind. Far-field major volcanic eruptions such as in the eastern Pacific may give rise to abnormally wet conditions through the global spread of the volcanic cloud. The El Chichón volcanic cloud was tracked by satellites across the Pacific Ocean and there is a match in the timing of heavy precipitation after the volcanic cloud entered the South China Sea about eleven days after the main eruption phase. Major volcanic eruptions are concluded to be a causative factor in monsoonal precipitation variability worthy of greater attention.

  9. Chronology and References of Volcanic Eruptions and Selected Unrest in the United States, 1980-2008

    USGS Publications Warehouse

    Diefenbach, Angela K.; Guffanti, Marianne; Ewert, John W.

    2009-01-01

    The United States ranks as one of the top countries in the world in the number of young, active volcanoes within its borders. The United States, including the Commonwealth of the Northern Mariana Islands, is home to approximately 170 geologically active (age <10,000 years) volcanoes. As our review of the record shows, 30 of these volcanoes have erupted since 1980, many repeatedly. In addition to producing eruptions, many U.S. volcanoes exhibit periods of anomalous activity, unrest, that do not culminate in eruptions. Monitoring volcanic activity in the United States is the responsibility of the U.S. Geological Survey (USGS) Volcano Hazards Program (VHP) and is accomplished with academic, Federal, and State partners. The VHP supports five Volcano Observatories - the Alaska Volcano Observatory (AVO), Cascades Volcano Observatory (CVO), Yellowstone Volcano Observatory (YVO), Long Valley Observatory (LVO), and Hawaiian Volcano Observatory (HVO). With the exception of HVO, which was established in 1912, the U.S. Volcano Observatories have been established in the past 27 years in response to specific volcanic eruptions or sustained levels of unrest. As understanding of volcanic activity and hazards has grown over the years, so have the extent and types of monitoring networks and techniques available to detect early signs of anomalous volcanic behavior. This increased capability is providing us with a more accurate gauge of volcanic activity in the United States. The purpose of this report is to (1) document the range of volcanic activity that U.S. Volcano Observatories have dealt with, beginning with the 1980 eruption of Mount St. Helens, (2) describe some overall characteristics of the activity, and (3) serve as a quick reference to pertinent published literature on the eruptions and unrest documented in this report.

  10. Prediction and monitoring of volcanic activities

    SciTech Connect

    Sudradjat, A.

    1986-07-01

    This paper summarizes the state of the art for predicting and monitoring volcanic activities, and it emphasizes the experience obtained by the Volcanological Survey Indonesia for active volcanoes. The limited available funds, the large number of active volcanoes to monitor, and the high population density of the volcanic area are the main problems encountered. Seven methods of volcano monitoring are applied to the active volcanoes of Indonesia: seismicity, ground deformation, gravity and magnetic studies, self-potential studies, petrochemistry, gas monitoring, and visual observation. Seismic monitoring augmented by gas monitoring has proven to be effective, particularly for predicting individual eruptions at the after-initial phase. However, the success of the prediction depends on the characteristics of each volcano. In general, the initial eruption phase is the most difficult phenomenon to predict. The preparation of hazard maps and the continuous awareness of the volcanic eruption are the most practical ways to mitigate volcanic danger.

  11. 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.

  12. Impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, Michael; Brinkop, Sabine; Jöckel, Patrick

    2016-05-01

    Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg - Modular Earth Submodel System (ECHAM/MESSy) Atmospheric Chemistry (EMAC) model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño-Southern Oscillation (ENSO) are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.

  13. Effects of Volcanic Eruptions on Stratospheric Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    2002-01-01

    The effects of the stratospheric sulfate aerosol layer associated with the Mt. Pinatubo volcano and future volcanic eruptions on the recovery of the ozone layer is studied with an interactive two-dimensional photochemical model. The time varying chlorine loading and the stratospheric cooling due to increasing carbon dioxide have been taken into account. The computed ozone and temperature changes associated with the Mt. Pinatubo eruption in 1991 agree well with observations. Long model runs out to the year 2050 have been carried out, in which volcanoes having the characteristics of the Mount Pinatubo volcano were erupted in the model at 10-year intervals starting in the year 2010. Compared to a non-volcanic run using background aerosol loading, transient reductions of globally averaged column ozone of 2-3 percent were computed as a result of each of these eruptions, with the ozone recovering to that computed for the non-volcanic case in about 5 years after the eruption. Computed springtime Arctic column ozone losses of from 10 to 18 percent also recovered to the non-volcanic case within 5 years. These results suggest that the long-term recovery of ozone would not be strongly affected by infrequent volcanic eruptions with a sulfur loading approximating Mt. Pinatubo. Sensitivity studies in which the Arctic lower stratosphere was forced to be 4 K and 10 K colder resulted in transient ozone losses of which also recovered to the non-volcanic case in 5 years. A case in which a volcano five times Mt. Pinatubo was erupted in the year 2010 led to maximum springtime column ozone losses of 45 percent which took 10 years to recover to the background case. Finally, in order to simulate a situation in which frequent smaller volcanic eruptions result in increasing the background sulfate loading, a simulation was made in which the background aerosol was increased by 10 percent per year. This resulted in a delay of the recovery of column ozone to 1980 values of more than 10 years.

  14. The effect of volcanic eruptions on the hydrological cycle

    NASA Astrophysics Data System (ADS)

    Iles, Carley; Hegerl, Gabriele

    2015-04-01

    Large explosive volcanic eruptions inject sulphur dioxide into the stratosphere where it is oxidised to sulphate aerosols which reflect sunlight. This causes a reduction in global temperature and precipitation lasting a few years. We investigate the robust features of this precipitation response, comparing climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) archive to three observational datasets, including one with ocean coverage. Global precipitation decreases significantly following eruptions in CMIP5 models, with the largest decrease in wet tropical regions. This also occurs in observational land data, and ocean data in the boreal cold season. In contrast, the dry tropical ocean regions show an increase in precipitation in CMIP5 models. Monsoon regions dry following eruptions in both models and observations, whilst in response to individual eruptions, the ITCZ shifts away from the hemisphere with the greater concentration of aerosols in CMIP5. The ocean response in CMIP5 is longer lasting than that over land, but observational results are too noisy to confirm this. We detect the influence of volcanism on precipitation in the boreal cold season, although the models underestimate the size of the response, whilst in the warm season the volcanic influence is marginally detectable. We then examine whether the influence of volcanoes can be seen in streamflow records for 50 major world rivers. Significant reductions in flow are found for the Amazon, Congo, Nile, Orange, Ob, Yenisey and Kolyma amongst others. When neighbouring rivers are combined into regions, informed by climate model predictions of the precipitation response to eruptions, decreases in streamflow can be detected in northern South American, central African and high-latitude Asian rivers and increases in southern South American and SW North American rivers. An improved understanding of how the hydrological cycle responds to volcanic eruptions is valuable in

  15. How many ensemble members are needed to identify a significant impact of volcanic eruptions?

    NASA Astrophysics Data System (ADS)

    Bittner, Matthias; Schmidt, Hauke; Timmreck, Claudia; Sienz, Frank

    2016-04-01

    Large tropical volcanic eruptions are assumed to cause a strengthening of the northern hemispheric stratospheric polar vortex. The downward propagation of this volcanic signal would then cause the observed winter warming pattern in Northern Eurasia. Several studies have indicate that state-of-the art climate models as represented in the recent CMIP5 activity in general fail at reproducing already the strengthening of the vortex in the first post eruption winters. Here we analyze the dynamical response of the atmosphere to large tropical volcanic eruptions as simulated in a large (100 member) ensemble of CMIP5 historical simulations (1850-2005) with the Max Planck Institute-Earth System Model (MPI-ESM). In this large ensemble, a post-volcanic vortex strengthening can easily be identified. We analyze stratospheric temperature and wind responses in the first NH winter with respect to the question how big an ensemble needs to be in order to obtain statistically significant signals. It becomes clear that the northern hemisphere winter stratosphere due to its natural and forced variability is the atmospheric time and region where the largest ensemble size is needed. Furthermore we show that using more but weaker volcanic eruptions may make the identification of signals more difficult than using few very large eruptions and confirm this by reanalyzing the multi-model CMIP5 data set

  16. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  17. Living through a volcanic eruption: Understanding the experience of survivors as a phenomenological existential phenomenon.

    PubMed

    Warsini, Sri; Mills, Jane; West, Caryn; Usher, Kim

    2016-06-01

    Mount Merapi in Indonesia is the most active volcano in the world with its 4-6-year eruption cycle. The mountain and surrounding areas are populated by hundreds of thousands of people who live near the volcano despite the danger posed to their wellbeing. The aim of this study was to explore the lived experience of people who survived the most recent eruption of Mount Merapi, which took place in 2010. Investigators conducted interviews with 20 participants to generate textual data that were coded and themed. Three themes linked to the phenomenological existential experience (temporality and relationality) of living through a volcanic eruption emerged from the data. These themes were: connectivity, disconnection and reconnection. Results indicate that the close relationship individuals have with Mount Merapi and others in their neighbourhood outweighs the risk of living in the shadow of an active volcano. This is the first study to analyze the phenomenological existential elements of living through a volcanic eruption. PMID:26892390

  18. Living through a volcanic eruption: Understanding the experience of survivors as a phenomenological existential phenomenon.

    PubMed

    Warsini, Sri; Mills, Jane; West, Caryn; Usher, Kim

    2016-06-01

    Mount Merapi in Indonesia is the most active volcano in the world with its 4-6-year eruption cycle. The mountain and surrounding areas are populated by hundreds of thousands of people who live near the volcano despite the danger posed to their wellbeing. The aim of this study was to explore the lived experience of people who survived the most recent eruption of Mount Merapi, which took place in 2010. Investigators conducted interviews with 20 participants to generate textual data that were coded and themed. Three themes linked to the phenomenological existential experience (temporality and relationality) of living through a volcanic eruption emerged from the data. These themes were: connectivity, disconnection and reconnection. Results indicate that the close relationship individuals have with Mount Merapi and others in their neighbourhood outweighs the risk of living in the shadow of an active volcano. This is the first study to analyze the phenomenological existential elements of living through a volcanic eruption.

  19. The volcanic response to deglaciation: Evidence from glaciated arcs and a reassessment of global eruption records

    NASA Astrophysics Data System (ADS)

    Watt, Sebastian F. L.; Pyle, David M.; Mather, Tamsin A.

    Several lines of evidence have previously been used to suggest that ice retreat after the last glacial maximum (LGM) resulted in regionally-increased levels of volcanic activity. It has been proposed that this increase in volcanism was globally significant, forming a substantial component of the post-glacial rise in atmospheric CO2, and thereby contributing to climatic warming. However, as yet there has been no detailed investigation of activity in glaciated volcanic arcs following the LGM. Arc volcanism accounts for 90% of present-day subaerial volcanic eruptions. It is therefore important to constrain the impact of deglaciation on arc volcanoes, to understand fully the nature and magnitude of global-scale relationships between volcanism and glaciation. The first part of this paper examines the post-glacial explosive eruption history of the Andean southern volcanic zone (SVZ), a typical arc system, with additional data from the Kamchatka and Cascade arcs. In all cases, eruption rates in the early post-glacial period do not exceed those at later times at a statistically significant level. In part, the recognition and quantification of what may be small (i.e. less than a factor of two) increases in eruption rate is hindered by the size of our datasets. These datasets are limited to eruptions larger than 0.1 km3, because deviations from power-law magnitude-frequency relationships indicate strong relative under-sampling at smaller eruption volumes. In the southern SVZ, where ice unloading was greatest, eruption frequency in the early post-glacial period is approximately twice that of the mid post-glacial period (although frequency increases again in the late post-glacial). A comparable pattern occurs in Kamchatka, but is not observed in the Cascade arc. The early post-glacial period also coincides with a small number of very large explosive eruptions from the most active volcanoes in the southern and central SVZ, consistent with enhanced ponding of magma during

  20. The lateral extent of volcanic interactions during unrest and eruption

    NASA Astrophysics Data System (ADS)

    Biggs, Juliet; Robertson, Elspeth; Cashman, Katharine

    2016-04-01

    Volcanic eruptions often occur simultaneously or tap multiple magma reservoirs. Such lateral interactions between magmatic systems are attributed to stress changes or hydraulic connections but the precise conditions under which coupled eruptions occur have yet to be quantified. Here we use interferometric synthetic aperture radar satellite data to analyse the surface deformation generated by volcanic unrest in the Kenyan Rift. We identify several magma sources located at depths of 2-5 km importantly, sources that are spaced less than about 10 km apart interact, whereas those spaced more than about 25 km apart do not. However, volcanoes up to 25 km apart have interacted in the geologic past. Thus, volcanic coupling is not simply controlled by the distance between the magma reservoirs. We then consider different tectonic settings globally, including intraplate volcanoes such as Hawaii and Yellowstone, arc volcanism in Alaska and Chile, and other rift settings, such as New Zealand, Iceland and Afar. We find that the most closely spaced magmatic interactions are controlled by the extent of a shallow crystal mush layer, stress changes can couple large eruptions over distances of about 20-40 km, and only large dyke intrusions or subduction earthquakes could generate coupled eruptions over distances of about 50-100 km.

  1. Comment on "The Latest on Volcanic Eruptions and Climate"

    NASA Astrophysics Data System (ADS)

    Johnson, Thomas C.; Lane, Christine S.

    2014-09-01

    Alan Robock (Eos, 94(35), 305-306, doi:10.1002/2013EO350001) nicely summarizes past volcanic eruptions and climate, but we wish to correct his assessment of our recent discovery of the Youngest Toba ash in the sediments of Lake Malawi in East Africa [Lane et al., 2013].

  2. Impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, M.; Brinkop, S.; Jöckel, P.

    2015-12-01

    Volcanic eruptions can have significant impact on the earth's weather and climate system. Besides the subsequent tropospheric changes also the stratosphere is influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour after the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as important sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on the tropospheric water vapour and ENSO are evident.

  3. Volcanic twilights from the fuego eruption.

    PubMed

    Volz, F E

    1975-07-01

    Striated twilight glows have been observed since 26 November 1974 in New England, indicating the spread of stratospheric dust earlier observed over Arizona. Similar photometric results were obtained from New Mexico and Florida, and twilights in Puerto Rico showed features not hitherto measured. Letters and verbal reports indicate the source to be eruptions of Fuego Volcano in Guatemala between 13 and 23 October 1974.

  4. Steady state volcanism: Evidence from eruption histories of polygenetic volcanoes

    SciTech Connect

    Wadge, G.

    1982-05-10

    Some volcanoes erupt magma at average rates which are constant over periods of many years, even through this magma may appear in a complex series of eruptions. This constancy of output is tested by construction of a curve of cumulative volume of erupted magma, which is linear for steady state volcanism, and whose gradient defines the steady state rate Q/sub s/s. The assumption is made that Q/sub s/s is the rate at which magma is supplied to these polygenetic volcanoes. Five general types of eruptive behavior can be distinguished from the cumulative volume studied. These types are interpreted in terms of a simple model of batches of magma rising buoyantly through the crust and interacting with a small-capacity subvolcanic magma reservoir. Recognition of previous steady state behavior at a volcano may enable the cumulative volume curve to be used empirically as a constraint on the timing and volume of the next eruption. The steady state model thus has a limited predictive capability. With the exception of Kilauea (O/sub s/s = 4m/sup 3/ s/sup -1/) all the identified steady state volcanoes have values of Q/sub s/s of a few tenths of one cubic meter per second. These rates are consistent with the minimum flux rates required by theoretical cooling models of batches of magma traversing the crust. The similarity of these Q/sub s/s values of volcanoes (producing basalt, andesite, and dacite magmas) in very different tectonic settings suggests that the common factors of crustal buoyancy forces and the geotherm-controlled cooling rates control the dynamics of magma supply through the crust. Long-term dormancy at active volcanoes may be a manifestation of the steady accumulation of magma in large crustal reservoirs, a process that complements the intermittent periods of steady state output at the surface. This possibility has several implications, the most important of which is that it provides a constraint on the supply rate of new magma to the bases of plutons.

  5. 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

  6. Using Blogs to Promote Alternative Perspective to Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Hamane, A.

    2011-12-01

    Distance learning is becoming more common in many higher education institutions making asynchronous online tools an essential component to promote positive student outcomes. California State University Los Angeles's online Natural Disasters course implements blogs as a collaborative constructive tool to allow students to build knowledge with their peers rather than to receive a body of facts in isolation. Blogs allow participants to post a chronological series of entries that give insight to thoughts and feelings about a specific event to a broader audience. In this course, students adopt an alternate identity and create a first-person commentary or diary entry as if they witnessed a historical volcanic event. Peers are instructed to post comments to blogs by offering sympathy, advice, solutions, or encouragement. Roleplaying between participants provides the opportunity for students to be engaged through multiple perspectives - a powerful means to understand societal impacts and to gain valuable insights. The blogging activity is devised so that novice students can complete the task on their own, yet read blog posts and comments from more capable peers. Anecdotal evidence suggests students have a greater appreciation and a deeper understanding of the impacts that volcanic eruptions have on society and the environment.

  7. Extreme Volcanic Eruptions: return periods, impact and implications (Invited)

    NASA Astrophysics Data System (ADS)

    Sparks, R. S.

    2010-12-01

    In the very short history of civilisation, a few thousand years, there have been comparably few very large volcanic events which global effects. Such events include very large lavas flow eruptions, such as Laki (Iceland) in 1783 and major caldera-forming explosive eruptions, such as Tambora in 1815 and Tianchi around 930 AD. Much larger magnitude eruptions have happened regularly when time scales of millions of years are considered. The modern globalised world is arguably uniquely vulnerable to very large volcanic events, making the study of their return periods, possible environmental effects and consequences a key goal of volcanology. A database of Quaternary large magnitude explosive eruptions (M ≥ 4) is under development as part of the VOGRIPA project on global volcanic hazards and risk. The database, currently consisting of 1929 entries from 481 Quaternary volcanoes, can be applied to constraining the magnitude-frequency relationship of global and regional explosive volcanism. Application of extreme value statistics to a Holocene subset of data, corrected for under-recording, enables construction of a magnitude-frequency relationship for global volcanism. Return periods based on maximum likelihood statistical analysis are 7.9 years for M ≥ 4, 35 years for M ≥ 5, and 370 years for M ≥ 7.0 with uncertainty increasing with magnitude. The return periods depend on the threshold chosen between the main part of the distribution and the extreme value tail and the results cited here are for a threshold of M = 4. For the largest magnitude eruptions (M > 7.5) the Holocene period is too short to obtain a meaningful result. The effects if an eruption like Tambora 1815 (M ~ 6.9) in the modern world is likely to be dramatic as the populations in SE Asia are now well over 20 time greater and the socio-economic vulnerability has also increased. Effects will include atmospheric pollution lasting a few years, major global climate perturbations and regional disruption

  8. Possible effects of volcanic eruptions on stratospheric minor constituent chemistry

    NASA Technical Reports Server (NTRS)

    Stolarski, R. S.; Butler, D. M.

    1979-01-01

    Although stratosphere penetrating volcanic eruptions have been infrequent during the last half century, periods have existed in the last several hundred years when such eruptions were significantly more frequent. Several mechanisms exist for these injections to affect stratospheric minor constituent chemistry, both on the long-term average and for short-term perturbations. These mechanisms are reviewed and, because of the sensitivity of current models of stratospheric ozone to chlorine perturbations, quantitative estimates are made of chlorine injection rates. It is found that, if chlorine makes up as much as 0.5 to 1% of the gases released and if the total gases released are about the same magnitude as the fine ash, then a major stratosphere penetrating eruption could deplete the ozone column by several percent. The estimate for the Agung eruption of 1963 is just under 1% an amount not excluded by the ozone record but complicated by the peak in atmospheric nuclear explosions at about the same time.

  9. 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.

  10. Volcanic geology and eruption frequency, São Miguel, Azores

    USGS Publications Warehouse

    Moore, Richard B.

    1990-01-01

    Six volcanic zones comprise São Miguel, the largest island in the Azores. All are Quaternary in age except the last, which is partly Pliocene. From west to east the zones are (1) the trachyte stratovolcano of Sete Cidades, (2) a field of alkali-basalt cinder cones and lava flows with minor trachyte, (3) the trachyte stratovolcano of Agua de Pau, (4) a field of alkali-basalt cinder cones and lava flows with minor trachyte and tristanite, (5) the trachyte stratovolcano of Furnas, and (6) the Nordeste shield, which includes the Povoação caldera and consists of alkali basalt, tristanite, and trachyte. New radiocarbon and K-Ar ages augment stratigraphic data obtained during recent geologic mapping of the entire island and provide improved data to interpret eruption frequency. Average dormant intervals for the past approximately 3000 years in the areas active during that time are about 400 years for Sete Cidades, 145 for zone 2, 1150 for Agua de Pau, and 370 for Furnas. However, the average dormant interval at Sete Cidades increased from 400 to about 680 years before each of the past two eruptions, and the interval at Furnas decreased from 370 to about 195 years before each of the past four eruptions. Eruptions in zone 4 occurred about once every 1000 years during latest Pleistocene and early Holocene time; none has occurred for about 3000 years. The Povoação caldera truncates part of the Nordeste shield and probably formed during the middle to late Pleistocene. Calderas formed during latest Pleistocene time at the three younger stratovolcanoes in the sequence: outer Agua de Pau (between 46 and 26.5 ka), Sete Cidades (about 22 ka), inner Agua de Pau (15.2 ka), and Furnas (about 12 ka). Normal faults are common, but many are buried by Holocene trachyte pumice. Most faults trend northwest or west-northwest and are related to the Terceira rift, whose most active segment on São Miguel passes through Sete Cidades and zone 2. A major normal fault displaces Nordeste

  11. Consistent decrease in North Atlantic Tropical Cyclone frequency following major volcanic eruptions in the last three centuries

    NASA Astrophysics Data System (ADS)

    Guevara-Murua, A.; Hendy, E. J.; Rust, A. C.; Cashman, K. V.

    2015-11-01

    Injection of sulphate aerosols into the stratosphere following major volcanic eruptions alters global climate through the absorption and scattering of solar radiation. One proposed consequence is a decrease in North Atlantic Tropical Cyclone (TC) activity, as was observed following the El Chichón (1982) and Mount Pinatubo (1991) eruptions. We test this relationship using documentary and proxy reconstructions of major volcanic eruptions and TC frequency in the North Atlantic basin over the last three centuries. We find a consistent reduction in the number of TCs formed during the 3 years following major eruptions compared to the preceding 3 years, including after eruptions located at northern high latitudes. Our findings suggest that low-latitude eruptions reduce Atlantic TC frequency by decreasing local sea surface temperatures, whereas the mechanisms for the decrease in TC frequency following high-latitude eruptions are less clear and attribution is hampered by poor identification of these events.

  12. Beyond baking soda: Demonstrating the link between volcanic eruptions and viscosity to all ages

    NASA Astrophysics Data System (ADS)

    Smithka, I. N.; Walters, R. L.; Harpp, K. S.

    2014-12-01

    Public interest in volcanic eruptions and societal relevance of volcanic hazards provide an excellent basis for successful earth science outreach. During a museum-based earth science outreach event free and open to the public, we used two new interactive experiments to illustrate the relationship between gas content, magma viscosity, and eruption style. Learning objectives for visitors are to understand: how gas drives volcanic eruptions, the differences between effusive and explosive eruption styles, viscosity's control on gas pressure within a magma reservoir, and the role of gas pressure on eruption style. Visitors apply the scientific method by asking research questions and testing hypotheses by conducting the experiments. The demonstrations are framed with real life examples of volcanic eruptions (e.g., Mt. St. Helens eruption in 1980), providing context for the scientific concepts. The first activity demonstrates the concept of fluid viscosity and how gas interacts with fluids of different viscosities. Visitors blow bubbles into water and corn syrup. The corn syrup is so viscous that bubbles are trapped, showing how a more viscous material builds up higher gas pressure. Visitors are asked which kind of magma (high or low viscosity) will produce an explosive eruption. To demonstrate an explosive eruption, visitors add an Alka-Seltzer tablet to water in a snap-top film canister. The reaction rapidly produces carbon dioxide gas, increasing pressure in the canister until the lid pops off and the canister launches a few meters into the air (tinyurl.com/nzsgfoe). Increasing gas pressure in the canister is analogous to gas pressure building within a magma reservoir beneath a volcano. The lid represents high-viscosity magma that prevents degassing, causing gas pressure to reach explosive levels. This interactive activity is combined with a display of an effusive eruption: add vinegar to baking soda in a model volcano to produce a quick-flowing eruption. These

  13. Effects of deglaciation on the petrology and eruptive history of the Western Volcanic Zone, Iceland

    NASA Astrophysics Data System (ADS)

    Eason, Deborah E.; Sinton, John M.; Grönvold, Karl; Kurz, Mark D.

    2015-06-01

    New observations and geochemical analyses of volcanic features in the 170-km-long Western Volcanic Zone (WVZ) of Iceland constrain spatial and temporal variations in volcanic production and composition associated with the last major deglaciation. Subglacial eruptions represent a significant portion of the late Quaternary volcanic budget in Iceland. Individual features can have volumes up to ˜48 km3 and appear to be monogenetic. Subaqueous to subaerial transition zones provide minimum estimates of ice sheet thickness at the time of eruption, although water-magma interactions and fluctuating lake levels during eruption can lead to complex lithological sequences. New major and trace element data for 36 glacial and postglacial eruptive units, combined with observations of lava surface quality, passage zone heights, and 3He exposure ages of some glacial units, indicate a maximum in volcanic production in the WVZ during the last major ice retreat. Anomalously high volcanic production rates continue into the early postglacial period and coincide with significant incompatible element depletions and slightly higher CaO and SiO2 and lower FeO content at a given MgO. Subglacial units with strong incompatible element depletions also have lava surfaces that lack evidence of subsequent glaciation. These units likely formed after the onset of deglaciation, when rapidly melting ice sheets increased decompression rates in the underlying mantle, leading to anomalously high melting rates in the depleted upper mantle. This process also can explain the eruption of extremely depleted picritic lavas during the early postglacial period. These new observations indicate that the increased volcanic activity associated with glacial unloading peaked earlier than previously thought, before Iceland was completely ice free.

  14. Assessing probabilistic forecasts of volcanic eruption onsets

    NASA Astrophysics Data System (ADS)

    Bebbington, Mark S.

    2013-12-01

    A method for assessing prospectively the quality of a suite of eruption forecasts is proposed. Any forecast of the next eruption onset from a polygenetic volcano can be converted into a probability distribution for the elapsed time since the forecast is made. This probability distribution, which effectively becomes a statistical P value when the observation is "plugged in," will thus itself have a uniform distribution under the null hypothesis that the forecast correctly describes the process. Given sufficient realizations, which may be on the same or different volcanoes, we can use standard statistical tests, such as the Kolmogorov-Smirnov test, to determine if the forecasts are consistent with the model(s). The use of the Kolmogorov-Smirnov test enables currently open forecasts to be included via the Kaplan-Meier product-limit estimator. While consistent underestimates (or overestimates) of the repose length will result in a median greater (or less) than , the method also assesses whether the method assigns the correct degree of aleatory variability to the forecast. Note that it is possible for the forecasts to be less precise than claimed. This would be indicated by the median of the sample being around , but the quartiles being well outside the interval, for example. The method is illustrated on the author's library of forecasts dating back to 1994, including renewal models and other point processes, on a gallery of approximately 20 volcanoes including Etna, Aso, and Ruapehu.

  15. Using Volcanic Lightning Measurements to Discern Variations in Explosive Volcanic Activity

    NASA Astrophysics Data System (ADS)

    Behnke, S. A.; Thomas, R. J.; McNutt, S. R.; Edens, H. E.; Krehbiel, P. R.; Rison, W.

    2013-12-01

    VHF observations of volcanic lightning have been made during the recent eruptions of Augustine Volcano (2006, Alaska, USA), Redoubt Volcano (2009, Alaska, USA), and Eyjafjallajökull (2010, Iceland). These show that electrical activity occurs both on small scales at the vent of the volcano, concurrent with an eruptive event and on large scales throughout the eruption column during and subsequent to an eruptive event. The small-scale discharges at the vent of the volcano are often referred to as 'vent discharges' and are on the order of 10-100 meters in length and occur at rates on the order of 1000 per second. The high rate of vent discharges produces a distinct VHF signature that is sometimes referred to as 'continuous RF' radiation. VHF radiation from vent discharges has been observed at sensors placed as far as 100 km from the volcano. VHF and infrasound measurements have shown that vent discharges occur simultaneously with the onset of eruption, making their detection an unambiguous indicator of explosive volcanic activity. The fact that vent discharges are observed concurrent with explosive volcanic activity indicates that volcanic ejecta are charged upon eruption. VHF observations have shown that the intensity of vent discharges varies between eruptive events, suggesting that fluctuations in eruptive processes affect the electrification processes giving rise to vent discharges. These fluctuations may be variations in eruptive vigor or variations in the type of eruption; however, the data obtained so far do not show a clear relationship between eruption parameters and the intensity or occurrence of vent discharges. Further study is needed to clarify the link between vent discharges and eruptive behavior, such as more detailed lightning observations concurrent with tephra measurements and other measures of eruptive strength. Observations of vent discharges, and volcanic lightning observations in general, are a valuable tool for volcano monitoring, providing a

  16. Volcanic activity: a review for health professionals.

    PubMed Central

    Newhall, C G; Fruchter, J S

    1986-01-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace elements composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); "mudflows" (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity. Images FIGURE 1 FIGURE 2 FIGURE 6a-6e FIGURE 6a-6e FIGURE 8 FIGURE 9 FIGURE 10 FIGURE 11 PMID:3946726

  17. Volcanic activity: a review for health professionals

    SciTech Connect

    Newhall, C.G.; Fruchter, J.S.

    1986-03-01

    Volcanoes erupt magma (molten rock containing variable amounts of solid crystals, dissolved volatiles, and gas bubbles) along with pulverized pre-existing rock (ripped from the walls of the vent and conduit). The resulting volcanic rocks vary in their physical and chemical characteristics, e.g., degree of fragmentation, sizes and shapes of fragments, minerals present, ratio of crystals to glass, and major and trace element composition. Variability in the properties of magma, and in the relative roles of magmatic volatiles and groundwater in driving an eruption, determine to a great extent the type of an eruption; variability in the type of an eruption in turn influences the physical characteristics and distribution of the eruption products. The principal volcanic hazards are: ash and larger fragments that rain down from an explosion cloud (airfall tephra and ballistic fragments); flows of hot ash, blocks, and gases down the slopes of a volcano (pyroclastic flows); mudflows (debris flows); lava flows; and concentrations of volcanic gases in topographic depressions. Progress in volcanology is bringing improved long- and short-range forecasts of volcanic activity, and thus more options for mitigation of hazards. Collaboration between health professionals and volcanologists helps to mitigate health hazards of volcanic activity.

  18. Compound Antidunes: a Key to Detect Catastrophic Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Yoshida, S.; Nemoto, Y.

    2008-12-01

    Antidunes are common in pyroclastic flow and surge deposits. However, the compound or nested occurrence of antidunes, where smaller antidunes reside within a larger-scale antidune, has seldom been documented or discussed in both pyroclastic and siliciclastic depositional settings. Without realizing this complexity, the frequency and magnitude of volcanic eruptions estimated from pyroclastic deposits are severely unrealistic. We have documented the Holocene outcrops of the antidune-bearing pyroclastites in Niijima Island, 100 miles SSW of Tokyo, Japan. The pyroclastites were formed by the eruptions in 886 AD Along the Habushiura coast in the southeastern part of the island, these outcrops form up to 50 m high cliffs, and are laterally traceable over 5 km from the volcano crater that shed the pyroclastites in the northward (downcurrent) direction. These pyroclastites were previously interpreted as recording about 30 small eruptions, each forming a 0.5-2 meter thick subhorizontal couplet of pumice (inversely grading) and lithic (normal grading) debris, with cm-m thick antidunes. However, we postulate that each of these couplets does not record a single volcanic eruption, but a much shorter time. These couplets occur between concave-up vertical accretion surfaces, which have both upstream- and downstream-migration components, within a 5-15 meter thick compound antidune (our "rank-1" antidune). Three erosively stacked compound antidunes form the coastal cliffs in the Habushiura coast, and each compound antidune is about ten times thicker than antidunes reported by earlier workers (corresponding to our "rank-2 antidunes" that nest within a rank-1 antidune, and "rank-3 antidunes" that nest within a rank-2 antidune). Hence, the Habushiura cliffs represent only three eruption events (instead of 30 events), but each representing much larger magnitude of eruptions. The geometry of these antidunes is comparable to "sediment waves" or "cyclic steps" of siliciclastic deposits

  19. Late Quaternary history of the Vakinankaratra volcanic field (central Madagascar): insights from luminescence dating of phreatomagmatic eruption deposits

    NASA Astrophysics Data System (ADS)

    Rufer, Daniel; Preusser, Frank; Schreurs, Guido; Gnos, Edwin; Berger, Alfons

    2014-05-01

    The Quaternary Vakinankaratra volcanic field in the central Madagascar highlands consists of scoria cones, lava flows, tuff rings, and maars. These volcanic landforms are the result of processes triggered by intracontinental rifting and overlie Precambrian basement or Neogene volcanic rocks. Infrared-stimulated luminescence (IRSL) dating was applied to 13 samples taken from phreatomagmatic eruption deposits in the Antsirabe-Betafo region with the aim of constraining the chronology of the volcanic activity. Establishing such a chronology is important for evaluating volcanic hazards in this densely populated area. Stratigraphic correlations of eruption deposits and IRSL ages suggest at least five phreatomagmatic eruption events in Late Pleistocene times. In the Lake Andraikiba region, two such eruption layers can be clearly distinguished. The older one yields ages between 109 ± 15 and 90 ± 11 ka and is possibly related to an eruption at the Amboniloha volcanic complex to the north. The younger one gives ages between 58 ± 4 and 47 ± 7 ka and is clearly related to the phreatomagmatic eruption that formed Lake Andraikiba. IRSL ages of a similar eruption deposit directly overlying basement laterite in the vicinity of the Fizinana and Ampasamihaiky volcanic complexes yield coherent ages of 68 ± 7 and 65 ± 8 ka. These ages provide the upper age limit for the subsequently developed Iavoko, Antsifotra, and Fizinana scoria cones and their associated lava flows. Two phreatomagmatic deposits, identified near Lake Tritrivakely, yield the youngest IRSL ages in the region, with respective ages of 32 ± 3 and 19 ± 2 ka. The reported K-feldspar IRSL ages are the first recorded numerical ages of phreatomagmatic eruption deposits in Madagascar, and our results confirm the huge potential of this dating approach for reconstructing the volcanic activity of Late Pleistocene to Holocene volcanic provinces.

  20. Steady state volcanism - Evidence from eruption histories of polygenetic volcanoes

    NASA Technical Reports Server (NTRS)

    Wadge, G.

    1982-01-01

    Cumulative volcano volume curves are presented as evidence for steady-state behavior at certain volcanoes and to develop a model of steady-state volcanism. A minimum criteria of five eruptions over a year was chosen to characterize a steady-state volcano. The subsequent model features a constant head of magmatic pressure from a reservoir supplied from depth, a sawtooth curve produced by the magma arrivals or discharge from the subvolcanic reservoir, large volume eruptions with long repose periods, and conditions of nonsupply of magma. The behavior of Mts. Etna, Nyamuragira, and Kilauea are described and show continuous levels of plasma output resulting in cumulative volume increases. Further discussion is made of steady-state andesitic and dacitic volcanism, long term patterns of the steady state, and magma storage, and the lack of a sufficient number of steady-state volcanoes in the world is taken as evidence that further data is required for a comprehensive model.

  1. Total electron content anomalies associated with global VEI4 + volcanic eruptions during 2002-2015

    NASA Astrophysics Data System (ADS)

    Li, Wang; Guo, Jinyun; Yue, Jianping; Shen, Yi; Yang, Yang

    2016-10-01

    In previous studies, little attention has been paid to the total electron content (TEC) anomalies preceding the volcanic eruption. We analyze the coupling relationship between volcanic eruption and TEC anomalies, and discuss the spatial distribution of TEC anomalies associated with volcanic geographical location. We utilize the global ionosphere map (GIM) data from the Center for Orbit Determination in Europe (CODE) to analyze TEC variations before the global volcanic eruptions indicated by VEI (Volcanic Explosivity Index) 4 + from 2002 to 2015 with the sliding interquartile range method. The results indicate the occurrence rate of TEC anomalies before great volcanic eruptions is related with the volcanic type and geographical position. The occurrence rate of TEC anomalies before stratovolcano and caldera eruptions is higher than that before shield and pyroclastic shield eruptions, and the occurrence rate of TEC anomalies has a descending trend from low latitudes to high latitudes. The TEC anomalies before the volcanic eruptions in low-mid latitudes are within the volcanic affected areas, but do not coincide with the volcanic foci. The corresponding TEC anomalies could be observed in the conjugated region, and all the TEC anomalies in the volcanic affected areas are usually close to bounds of equatorial anomaly zones. However, the TEC anomalies preceding these eruptions in high latitudes usually surround the volcano, and no TEC anomalies appear in the conjugated region. These conclusions have potential applications to the prediction of great volcanic eruptions in the future.

  2. 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

  3. Demonstrating the Importance of Bubbles and Viscosity on Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Namiki, A.

    2005-12-01

    The behavior of bubbles (exsolved volatile from magma) and viscosity of magma are important parameters that influence volcanic eruptions. Exsolved volatiles increase the volume of magma and reduce its density so that magma has sufficient volume and buoyancy force to erupt. Volatiles exsolve through nucleation and growth by diffusion and bubbles can expand as pressure is reduced. The time scale of diffusion depends on the viscosity of surrounding magma, and the expansion time scale of a bubble is also depends on the viscosity of magma. These control the time scale for volume change. If bubbles segregate from magma and collapse, the magma might not able to expand sufficiently to erupt violently. Whether a bubble can segregate from the liquid part of magma is also depends on viscosity of magma. In this poster, I introduce a straightforward demonstration to show the importance of bubbles and viscosity of magma on volcanic eruptions. To make bubbles, I use baking soda (NaHCO3) and citric acid. Reaction between them generates carbon dioxide (CO2) to make bubbles. I make citric acid solution gel by using agar at the bottom of a transparent glass and pour baking soda disolved corn syrup on top of the agar. This situation is a model of basally heated magma chamber. When water disolved magma (baking soda disolved corn syrup) receives sufficient heat (citric acid) bubbles are generated. I can change viscosity of corn syrup by varying the concentration of water. This demonstration shows how viscosity controls the time scale of volume change of bubbly magma and the distribution of bubbles in the fluid. In addition it helps to understand the important physical processes in volcanic eruption: bubble nucleation, diffusion grows, expansion, and bubble driving convection. I will perform a live demonstration at the site of the poster.

  4. The Evolving Structure of Young Volcanic Eruption Clouds

    NASA Astrophysics Data System (ADS)

    Carn, S. A.; Bursik, M. I.

    2015-12-01

    Processes acting in nascent volcanic clouds within seconds to hours of eruption (e.g., ash aggregation, ice nucleation, gravity waves) set the stage for subsequent advection and diffusion of volcanic ash, hence strongly influence aviation hazards and atmospheric impacts, but are very difficult to observe. Young plumes initially spread by gravity in the crosswind direction due to density differences with the surrounding stratified atmosphere. Subsequently, plumes lose their density contrast with the atmosphere and are advected as lenses of aerosol and gas, slowly thinning, spreading and dispersing as shearing and small scale turbulence act at their margins, and as fine ash settles out. Since 2006, satellite observations from NASA's A-Train constellation, including the CALIOP lidar and CloudSat radar, have provided tantalizing glimpses of young volcanic clouds in the first few hours of atmospheric residence. These unique observations, although spatially limited, provide insight into the evolving structure of young volcanic clouds from an optically thick, vertically extensive initial state to thin layers confined to a limited altitude range. Layered volcanic clouds may develop due to the existence of alternating turbulent and stable layers in the free troposphere and stratosphere. Turbulent layers retain particles longer than do quiescent layers because the turbulence retains particles in suspension. Particles fall more rapidly through the quiescent layers by single particle settling, or more rapidly because of convective sedimentation. The result is a distinct, banded ash cloud structure. We present A-Train satellite observations of volcanic clouds at various stages of evolution from several recent eruptions (including Kelut, Redoubt, Chaitén, Eyjafjallajökull, Okmok and Kasatochi) and also show the results of preliminary model simulations of the development of volcanic cloud layering.

  5. Climate Curriculum Modules on Volcanic Eruptions, Geoengineering, and Nuclear Winter

    NASA Astrophysics Data System (ADS)

    Robock, A.

    2014-12-01

    To support a climate dynamics multidisciplinary curriculum for graduate and senior university students, I will describe on-line modules on volcanic eruptions and climate, geoengineering, and nuclear winter. Each of these topics involves aerosols in the stratosphere and the response of the climate system, but each is distinct, and each is evolving as more research becomes available. As reported for the first time in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, volcanic eruptions are a natural analog for the climate impacts of potential anthropogenic aerosol injections into the stratosphere, either sulfates from potential attempts to cool the climate to counteract global warming, or smoke that would be produced from fires in cities and industrial targets in a nuclear war. The volcanic eruptions module would stand alone, and would also serve as a prerequisite for each of the other two modules, which could be taught independently of each other. Each module includes consideration of the physical climate system as well as impacts of the resulting climate change. Geoengineering includes both solar radiation management and carbon dioxide reduction. The geoengineering and nuclear winter modules also include consideration of policy and governance issues. Each module includes a slide set for use in lecturing, links to related resources, and student exercises. The modules will be regularly updated.

  6. Significant statistically relationship between the great volcanic eruptions and the count of sunspots from 1610 to the present

    NASA Astrophysics Data System (ADS)

    Casati, Michele

    2014-05-01

    The assertion that solar activity may play a significant role in the trigger of large volcanic eruptions is, and has been discussed by many geophysicists. Numerous scientific papers have established a possible correlation between these events and the electromagnetic coupling between the Earth and the Sun, but none of them has been able to highlight a possible statistically significant relationship between large volcanic eruptions and any of the series, such as geomagnetic activity, solar wind, sunspots number. In our research, we compare the 148 volcanic eruptions with index VEI4, the major 37 historical volcanic eruptions equal to or greater than index VEI5, recorded from 1610 to 2012 , with its sunspots number. Staring, as the threshold value, a monthly sunspot number of 46 (recorded during the great eruption of Krakatoa VEI6 historical index, August 1883), we note some possible relationships and conduct a statistical test. • Of the historical 31 large volcanic eruptions with index VEI5+, recorded between 1610 and 1955, 29 of these were recorded when the SSN<46. The remaining 2 eruptions were not recorded when the SSN<46, but rather during solar maxima of the solar cycle of the year 1739 and in the solar cycle No. 14 (Shikotsu eruption of 1739 and Ksudach 1907). • Of the historical 8 large volcanic eruptions with index VEI6+, recorded from 1610 to the present, 7 of these were recorded with SSN<46 and more specifically, within the three large solar minima known : Maunder (1645-1710), Dalton (1790-1830) and during the solar minimums occurred between 1880 and 1920. As the only exception, we note the eruption of Pinatubo of June 1991, recorded in the solar maximum of cycle 22. • Of the historical 6 major volcanic eruptions with index VEI5+, recorded after 1955, 5 of these were not recorded during periods of low solar activity, but rather during solar maxima, of the cycles 19,21 and 22. The significant tests, conducted with the chi-square χ ² = 7,782, detect a

  7. Hydrogeomorphic effects of explosive volcanic eruptions on drainage basins

    USGS Publications Warehouse

    Pierson, Thomas C.; Major, Jon J.

    2014-01-01

    Explosive eruptions can severely disturb landscapes downwind or downstream of volcanoes by damaging vegetation and depositing large volumes of erodible fragmental material. As a result, fluxes of water and sediment in affected drainage basins can increase dramatically. System-disturbing processes associated with explosive eruptions include tephra fall, pyroclastic density currents, debris avalanches, and lahars—processes that have greater impacts on water and sediment discharges than lava-flow emplacement. Geo-morphic responses to such disturbances can extend far downstream, persist for decades, and be hazardous. The severity of disturbances to a drainage basin is a function of the specific volcanic process acting, as well as distance from the volcano and magnitude of the eruption. Postdisturbance unit-area sediment yields are among the world's highest; such yields commonly result in abundant redeposition of sand and gravel in distal river reaches, which causes severe channel aggradation and instability. Response to volcanic disturbance can result in socioeconomic consequences more damaging than the direct impacts of the eruption itself.

  8. Classification of Volcanic Eruptions on Io and Earth Using Low-Resolution Remote Sensing Data

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Keszthelyi, L. P.

    2005-01-01

    Two bodies in the Solar System exhibit high-temperature active volcanism: Earth and Io. While there are important differences in the eruptions on Earth and Io, in low-spatial-resolution data (corresponding to the bulk of available and foreseeable data of Io), similar styles of effusive and explosive volcanism yield similar thermal flux densities. For example, a square metre of an active pahoehoe flow on Io looks very similar to a square metre of an active pahoehoe flow on Earth. If, from observed thermal emission as a function of wavelength and change in thermal emission with time, the eruption style of an ionian volcano can be constrained, estimates of volumetric fluxes can be made and compared with terrestrial volcanoes using techniques derived for analysing terrestrial remotely-sensed data. In this way we find that ionian volcanoes fundamentally differ from their terrestrial counterparts only in areal extent, with Io volcanoes covering larger areas, with higher volumetric flux. Io outbursts eruptions have enormous implied volumetric fluxes, and may scale with terrestrial flood basalt eruptions. Even with the low-spatial resolution data available it is possible to sometimes constrain and classify eruption style both on Io and Earth from the integrated thermal emission spectrum. Plotting 2 and 5 m fluxes reveals the evolution of individual eruptions of different styles, as well as the relative intensity of eruptions, allowing comparison to be made from individual eruptions on both planets. Analyses like this can be used for interpretation of low-resolution data until the next mission to the jovian system. For a number of Io volcanoes (including Pele, Prometheus, Amirani, Zamama, Culann, Tohil and Tvashtar) we do have high/moderate resolution imagery to aid determination of eruption mode from analyses based only on low spatial-resolution data.

  9. Improved Constraints on the Eruptive History of Northern Harrat Rahat Volcanic Field, Kingdom of Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Stelten, M. E.; Downs, D. T.; Calvert, A. T.; Sherrod, D. R.; Hassan, K. H.; Muquyyim, F. A.; Ashur, M. S.

    2015-12-01

    Harrat Rahat is a large (~20,000 km2) alkalic volcanic field located in central western Saudi Arabia. A variety of eruptive products ranging from alkali basalt to trachyte have erupted at Harrat Rahat over the past ~10 m.y., with the most recent eruptions occurring at 641 CE (uncertain) and 1256 CE in the northern part of the volcanic field. Despite the field's young age and its close proximity to two major city centers, the eruptive history of Harrat Rahat remains poorly constrained. Previous researchers grouped the volcanic strata of northern Harrat Rahat into seven subunits based on limited K-Ar and 40Ar/39Ar dating, and on the degree of erosion displayed by the eruptive products. The youngest eruptive products (subunits Qm7 - Qm4) are thought to be ≤600 ka, whereas the older lavas (Qm3 - Qm1) are thought to be >600 ka. However, due to the sparse geochronologic control on the ages of the eruptive units, it remains unclear if the currently defined subunits accurately reflect the age distribution of lavas in northern Harrat Rahat. Additionally, the temporal relation between basaltic magmatism and the more evolved eruptive products has yet to be examined. To better constrain the eruptive history of Harrat Rahat we measured >50 new 40Ar/39Ar eruption ages for Qm1 through Qm5 lavas in northern Harrat Rahat. These new 40Ar/39Ar ages suggest that the majority of volcanism in the region occurred ≤400 ka and is significantly younger than previously thought, indicating that the magmatic system at Harrat Rahat has been more active over the past 400 kyr then previously recognized. Additionally, these new age data suggest that nearly all trachytic magmatism occurred <125 ka and was preceded by a pulse of more mafic magmatism. It is likely the magmatic system at Harrat Rahat reached an evolved state late in the history of the volcanic field due to increased and/or prolonged input of basaltic magmas into the crust.

  10. Building the Volcanic Oceanic Crust One Eruption at a Time (Invited)

    NASA Astrophysics Data System (ADS)

    Sinton, J. M.; Rubin, K. H.; White, S. M.; Colman, A.; Bowles, J. A.; Gronvold, K.

    2010-12-01

    The physical and chemical characteristics of lava flow fields formed during individual volcanic eruptions provides critical information on the nature of underlying magma reservoirs and the diking events that feed magma to the surface. Chemical variability of individual flow fields can constrain important parameters, such as the depth, geometry, melt percentage, and cooling rate of magma reservoirs and, in some case, whether or not dikes traveled vertically from magma reservoirs to the surface, with examples from the East Pacific Rise, Juan de Fuca Ridge and Iceland. Lava flow morphology and the length of ridge activated during individual eruptions constrain eruption rates and, in some cases, how eruption rates and magma sources vary during the course of long-lived eruptions. Although the study of submarine volcanic eruptions has historically been dominated by study of very recent flow fields or remotely detected “events”, a recent cruise to the Galápagos Spreading Center demonstrated that volcanic geology can be deciphered for areas of seafloor using the same basic methods commonly employed on-land: near-bottom geological observations, remote images at the appropriate spatial resolution, and petrologic and geochronologic study of samples. For the Galápagos study we used the AUV Sentry to obtain very high resolution (~1-m spatial scale) bathymetry, 26 Alvin dives, 17 camera-tows, and on-shore chemical and magnetic paeleointensity sample analyses to identify the areal extents, chemical variability and age constraints of at least 14 previously unknown discrete eruptive units in two areas with highly contrasting average magma supply defined by variations in crustal thickness and spreading rate. Preliminary general results of this study indicate that, at high magma supply, relatively low-volume eruptions are fed from shallow, moderately to highly differentiated, melt-dominated magma chambers to elongate fissures at relatively high average eruption rates. At low

  11. A Brownian model for recurrent volcanic eruptions: an application to Miyakejima volcano (Japan)

    NASA Astrophysics Data System (ADS)

    Garcia-Aristizabal, Alexander; Marzocchi, Warner; Fujita, Eisuke

    2012-03-01

    The definition of probabilistic models as mathematical structures to describe the response of a volcanic system is a plausible approach to characterize the temporal behavior of volcanic eruptions and constitutes a tool for long-term eruption forecasting. This kind of approach is motivated by the fact that volcanoes are complex systems in which a completely deterministic description of the processes preceding eruptions is practically impossible. To describe recurrent eruptive activity, we apply a physically motivated probabilistic model based on the characteristics of the Brownian passage-time (BPT) distribution; the physical process defining this model can be described by the steady rise of a state variable from a ground state to a failure threshold; adding Brownian perturbations to the steady loading produces a stochastic load-state process (a Brownian relaxation oscillator) in which an eruption relaxes the load state to begin a new eruptive cycle. The Brownian relaxation oscillator and Brownian passage-time distribution connect together physical notions of unobservable loading and failure processes of a point process with observable response statistics. The Brownian passage-time model is parameterized by the mean rate of event occurrence, μ, and the aperiodicity about the mean, α. We apply this model to analyze the eruptive history of Miyakejima volcano, Japan, finding a value of 44.2 (±6.5 years) for the μ parameter and 0.51 (±0.01) for the (dimensionless) α parameter. The comparison with other models often used in volcanological literature shows that this physically motivated model may be a good descriptor of volcanic systems that produce eruptions with a characteristic size. BPT is clearly superior to the Exponential distribution, and the fit to the data is comparable to other two-parameters models. Nonetheless, being a physically motivated model, it provides an insight into the macro-mechanical processes driving the system.

  12. Observations of volcanic lightning during the 2009 eruption of Redoubt Volcano

    NASA Astrophysics Data System (ADS)

    Behnke, Sonja A.; Thomas, Ronald J.; McNutt, Stephen R.; Schneider, David J.; Krehbiel, Paul R.; Rison, William; Edens, Harald E.

    2013-06-01

    Observations of volcanic lightning during the eruption of Redoubt Volcano in March and April 2009 were made with the Lightning Mapping Array. During the eruption twenty-three distinct episodes of volcanic lightning were observed. Electrical activity occurred as either a volcanic lightning storm with up to thousands of lightning discharges or as a weak electrical event with only a handful of lightning discharges. During the volcanic lightning storms we observed two phases of electrical activity: the explosive phase and the plume phase. The explosive phase consisted of very small discharges (on the order of 10-100 m) occurring directly above the vent while an explosive eruption was ongoing, whereas the plume phase was comprised of discharges occurring throughout the plume subsequent to the explosive eruption. The area of discharges during the explosive phase ranged from less than 1 km2 to 50 km2 or more. The electrical activity at the beginning of the plume phase was dominated by small discharges. Over time the horizontal extent of the flashes increased, with the largest flashes occurring at the end of the plume phase. The distribution of the horizontal size of the discharges over the lifetime of the storm indicate that the charge structure of the plume evolved from a complex and ‘clumpy’ structure to a more simple horizontally stratified structure. Plume height was shown to be a key factor in the quantity of lightning in a storm. The volcanic lightning storms occurred in plumes with column heights greater than 10 km. The tall plumes may contribute to the efficiency of charge generation through ice collisions by providing strong updrafts from the large thermal energy input from the eruption.

  13. Intensification of tropical Pacific biological productivity due to volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Chikamoto, Megumi O.; Timmermann, Axel; Yoshimori, Masakazu; Lehner, Flavio; Laurian, Audine; Abe-Ouchi, Ayako; Mouchet, Anne; Joos, Fortunat; Raible, Christoph C.; Cobb, Kim M.

    2016-02-01

    Major volcanic eruptions generate widespread ocean cooling, which reduces upper ocean stratification. This effect has the potential to increase nutrient delivery into the euphotic zone and boost biological productivity. Using externally forced last millennium simulations of three climate/Earth System models (Model for Interdisciplinary Research On Climate (MIROC), Community Earth System Model (CESM), and LOch-Vecode-Ecbilt-CLio-agIsm Model (LOVECLIM)), we test the hypothesis that large volcanic eruptions intensify nutrient-driven export production. It is found that strong volcanic radiative forcing enhances the likelihood of eastern Pacific El Niño-like warming in CESM and LOVECLIM. This leads to an initial reduction of nutrients and export production in the eastern equatorial Pacific. However, this initial response reverses after about 3 years in association with La Niña cooling. The resulting delayed enhancement of biological production resembles the multiyear response in MIROC. The model simulations show that volcanic impacts on tropical Pacific dynamics and biogeochemistry persist for several years, thus providing a new source for potential multiyear ecosystem predictability.

  14. Was there a volcanic eruption off Vietnam in AD 608?

    NASA Astrophysics Data System (ADS)

    Khoo, T. T.

    In the Sui-shu (Annals of the Sui Dynasty, 581-618), there is a record that returning envoys of the Chinese court to a state in northeastern Malay peninsula had in April-June AD 608 reached the state of Lin-i where for a whole day's sail the air around the vessel was yellowish and fetid. Lin-i was located at the southern end of the Annam Highlands chain and it is interpreted here that the phenominon reported could be due to a volcanic eruption in the Poulo Cecir-Ile des Cendres-Veteran volcanic islands group near the area. During the months of May to June the winds of the southwest monsoon, too, blow from the volcanic area toward the southern end of the Annam Highlands.

  15. Two-phase volcanic eruptions: Compaction, compression, and choking

    NASA Astrophysics Data System (ADS)

    Bercovici, D.; Michaut, C.

    2009-12-01

    Volcanic eruptions involve turbulent, often super-sonic flows of gas and magma or ash mixtures. The mixture density is controlled both by gas content as well as gas compressibility, both of which vary according to different processes of compaction and compression, respectively. Moreover, the two phases of the mixture separate because of their different densities, and the interaction forces (turbulent drag and inertial exchange) can be complex. We develop and explore a model for two-phase, high Reynolds number flow of a compacting suspension of magma particles in a compressible gas. The model is used to examine acoustic-porosity wave propagation and the development of shocks or choking in a volcanic conduit. Standard pseudo-gas treatments of volcanic eruptions -- wherein the phases are assumed to move with the same velocity -- predict greatly reduced accoustic sound waves, and thus shock development at relatively low velocities. Sound waves in separable mixtures, however, are highly dispersive with fast waves propagating at the pure gas sound speed at small wavelengths, slow waves traveling at the pseudo-gas speed at long wavelengths, and pure attenuation and sound blocking at intermediate wavelengths. Short-wavelength disturbances on an erupting column will thus only induce shocks if the column's gas velocity reaches the gas sound speed. Long-wavelength disturbances will develop shocks if the column is erupting at least as fast as the reduced pseudo-gas sound speed. Intermediate-wavelength disturbances associated with sound blocking will induce shocks at any column velocity. However, steepening by shock development will force the long wavelength disturbances toward shorter wavelengths, at which point they can propagate up to the gas sound speed without inducing shocks. This dispersive behavior provides a natural mechanism by which long wavelength disturbances choke and then unchoke by shock steepening. Non-linear, finite-amplitude steady-state models of eruptions

  16. UK Hazard Assessment for a Laki-type Volcanic Eruption

    NASA Astrophysics Data System (ADS)

    Witham, Claire; Felton, Chris; Daud, Sophie; Aspinall, Willy; Braban, Christine; Loughlin, Sue; Hort, Matthew; Schmidt, Anja; Vieno, Massimo

    2014-05-01

    Following the impacts of the Eyjafjallajokull eruption in 2010, two types of volcanic eruption have been added to the UK Government's National Risk Register for Civil Emergencies. One of these, a large gas-rich volcanic eruption, was identified as a high impact natural hazard, one of the three highest priority natural hazards faced by the UK. This eruption scenario is typified by the Laki eruption in Iceland in 1783-1784. The Civil Contingency Secretariat (CCS) of the UK's Cabinet Office, responsible for Civil Protection in the UK, has since been working on quantifying the risk and better understanding its potential impacts. This involves cross-cutting work across UK Government departments and the wider scientific community in order to identify the capabilities needed to respond to an effusive eruption, to exercise the response and develop increased resilience where possible. As part of its current work, CCS has been working closely with the UK Met Office and other UK agencies and academics (represented by the co-authors and others) to generate and assess the impacts of a 'reasonable worst case scenario', which can be used for decision making and preparation in advance of an eruption. Information from the literature and the findings of an expert elicitation have been synthesised to determine appropriate eruption source term parameters and associated uncertainties. This scenario is then being used to create a limited ensemble of model simulations of the dispersion and chemical conversion of the emissions of volcanic gases during such an eruption. The UK Met Office's NAME Lagrangian dispersion model and the Centre for Ecology and Hydrology's EMEP4UK Eulerian model are both being used. Modelling outputs will address the likelihood of near-surface concentrations of sulphur and halogen species being above specified health thresholds. Concentrations at aviation relevant altitudes will also be evaluated, as well as the effects of acid deposition of volcanic species on

  17. Pre-eruption deformation and seismic anomalies in 2012 in Tolbachik volcanic zone, Kamchatka

    NASA Astrophysics Data System (ADS)

    Kugaenko, Yulia; Saltykov, Vadim; Titkov, Nikolay

    2014-05-01

    Tolbachik volcanic zone (active volcano Plosky Tolbachik, dormant volcano Ostry Tolbachik and Tolbachik zone of cinder cones) is situated in the south part of Klyuchevskaya group of volcanoes in Kamchatka. All historical fissure eruptions of Tolbachik volcanic zone (1740, 1941, 1975-76 and 2012-13) were connected with one or another activity of Plosky Tolbachik volcano. In 1941 the fissure vent was occurred during the completion of 1939-41 terminal eruption of Plosky Tolbachik. In 1975 the Large Tolbachik Fissure Eruption (LTFE) was forestalled by Plosky Tolbachik terminal activity of the Hawaiian type and then was accompanied by the catastrophic collapse in the crater of Plosky Tolbachik. What events took place in the vicinity of Plosky Tolbachik in 2012 before the 2012-13 fissure eruption? In contrast of the 1975-76 LTFE the eruption 2012-13 was not preceded by intensive seismic preparation. Nowadays Klyuchevskaya group of volcanoes is under monitoring by 12 seismic stations, so we can investigate seismicity in details on the lower energy level then forty years ago. We analyzed seismicity of Plosky Tolbachik using regional catalogue 1999-2012. Anomalies of low-energy (M≥1.5) seismicity parameters (increase of seismicity rate and seismic energy) were discovered. This is evidence of seismic activization covered the whole Plosky Tolbachik volcano. The significance of this anomaly was estimated by distribution function of emitted seismic energy. Statistically significant transition of seismicity from background level to high and extremely high levels was revealed. It corresponds to multiple growth of earthquake number and seismic energy in 2012, July-November (five months before the eruption). The seismicity transition from background level to high level was happen in August 2012. During last three weeks before fissure eruption seismicity of analyzed seismoactive volume was on extremely high level. Earthquakes from fissure site directly appeared only on November 27

  18. Volcanic plume measurements using a UAV for the 2014 Mt. Ontake eruption

    NASA Astrophysics Data System (ADS)

    Mori, Toshiya; Hashimoto, Takeshi; Terada, Akihiko; Yoshimoto, Mitsuhiro; Kazahaya, Ryunosuke; Shinohara, Hiroshi; Tanaka, Ryo

    2016-03-01

    A phreatic eruption of Mt. Ontake, Japan, started abruptly on September 27, 2014, and caused the worst volcanic calamity in recent 70 years in Japan. We conducted volcanic plume surveys using an electric multirotor unmanned aerial vehicle to elucidate the conditions of Mt. Ontake's plume, which is flowing over 3000 m altitude. A plume gas composition, sulfur dioxide flux and thermal image measurements and a particle sampling were carried out using the unmanned aerial vehicle for three field campaigns on November 20 and 21, 2014, and June 2, 2015. Together with the results of manned helicopter and aircraft observations, we revealed that the plume of Mt. Ontake was not directly emitted from the magma but was influenced by hydrothermal system, and observed SO2/H2S molar ratios were decreasing after the eruption. High SO2 flux of >2000 t/d observed at least until 20 h after the onset of the eruption implies significant input of magmatic gas and the flux quickly decreased to about 130 t/d in 2 months. In contrast, H2S fluxes retrieved using SO2/H2S ratio and SO2 flux showed significantly high level of 700-800 t/d, which continued at least between 2 weeks and 2 months after the eruption. This is a peculiar feature of the 2014 Mt. Ontake eruption. Considering the trends of the flux changes of SO2 and H2S, we presume that majority of SO2 and H2S are supplied, respectively, from high-temperature magmatic fluid of a deep origin and from hydrothermal system. From the point of view of SO2/H2S ratios and fumarolic temperatures, the plume degassing trend after the 2014 eruption is following the similar course as that after the 1979 eruptions, and we speculate the 2014 eruptive activity will cease slowly similar to the 1979 eruption.

  19. Bipolar volcanic events in ice cores and the Toba eruption at 74 ka BP (Invited)

    NASA Astrophysics Data System (ADS)

    Svensson, A.

    2013-12-01

    Acidity spikes in Greenland and Antarctic ice cores are applied as tracers of past volcanic activity. Besides providing information on the timing and magnitude of past eruptions, the acidity spikes are also widely used for synchronization of ice cores. All of the deep Greenland ice cores are thus synchronized throughout the last glacial cycle based on volcanic markers. Volcanic matching of ice cores from the two Hemispheres is much more challenging but it is feasible in periods of favourable conditions. Over the last two millennia, where ice cores are precisely dated, some 50 bipolar volcanic events have thus been identified. In order for an eruption to express a bipolar fingerprint it generally needs to be a low latitude eruption with stratospheric injection. Sometimes tephra is associated with the ice-core acidity spikes, but most often there is no tephra present in the ice. As yet, an unknown eruption occurring in 1259 AD is the only event reported to have deposited tephra in both Greenland and Antarctica. During the last glacial period bipolar volcanic matching is very challenging and very little work has been done, but recent high-resolution ice core records have the potential to provide bipolar ice core matching for some periods. Recently, Greenland and Antarctic ice cores have been linked by acidity spikes in the time window of the most recent eruption (the YTT eruption) of the Indonesian Toba volcano that is situated close to equator in Sumatra. Ash from this Toba event is widespread over large areas in Asia and has been identified as far west as Africa, but no corresponding tephra has been found in polar ice cores despite several attempts. The age of the YTT eruption is well constrained by recent Ar-Ar dating to have occurred some 74 ka ago close to the Marine Isotope Stage 4/5 boundary and close to the onset of the cold Greenland Stadial 20 and the corresponding mild Antarctic Isotopic Maxima 19 and 20. Surprisingly, no single outstanding acidity spike

  20. Satellite observations of lightning-generated NOx in volcanic eruption clouds

    NASA Astrophysics Data System (ADS)

    Carn, Simon; Krotkov, Nickolay; Pickering, Ken; Allen, Dale; Bucsela, Eric

    2016-04-01

    stratospheric contribution and tropospheric NO2 background and applies an appropriate air mass factor to convert the slant column LNO2 to a vertical column of LNOx. However, OMI measurements of LNOx in thunderstorms suggest that any NOx below the cloud optical centroid pressure (OCP; ~350-500 hPa) is not detected. We speculate that the OCP may be lower (i.e., at higher altitude) in fresh volcanic clouds due to higher optical depths. The observation of vLNOx in volcanic clouds is significant since it implies active convection and plume electrification close to the satellite overpass time, with implications for aviation hazards due to volcanic ash. Furthermore, the vLNOx observations may provide information on air entrainment in volcanic eruption columns, which is required for some volcanic ash dispersion models. Although vLNOx is undoubtedly a very minor fraction of global LNOx production, explosive volcanic eruptions may inject NOx into the stratosphere where it has implications for ozone chemistry.

  1. Short-term spatial change in a volcanic tremor source during the 2011 Kirishima eruption

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Shimizu, Hiroshi; Matsushima, Takeshi; Uehira, Kenji; Yamashita, Yusuke; Nakamoto, Manami; Miyazaki, Masahiro; Chikura, Hiromi

    2013-04-01

    Volcanic tremors are indicators of magmatic behavior, which is strongly related to volcanic eruptions and activity. Detection of spatial and temporal variations in the source location is important for understanding the mechanism of volcanic eruptions. However, short-term temporal variations within a tremor event have not always been detected by seismic array observations around volcanoes. Here, we show that volcanic tremor sources were activated at both the top (i.e., the crater) and the lower end of the conduit, by analyzing seismograms from a dense seismic array 3 km from the Shinmoedake crater, Kirishima volcano, Japan. We observed changes in the seismic ray direction during a volcanic tremor sequence, and inferred two major sources of the tremor from the slowness vectors of the approaching waves. One was located in a shallow region beneath the Shinmoedake crater. The other was found in a direction N30°W from the array, pointing to a location above a pressure source. The fine spatial and temporal characteristics of volcanic tremors suggest an interaction between deep and shallow conduits.

  2. Bromo volcano area as human-environment system: interaction of volcanic eruption, local knowledge, risk perception and adaptation strategy

    NASA Astrophysics Data System (ADS)

    Bachri, Syamsul; Stötter, Johann; Sartohadi, Junun

    2013-04-01

    People in the Bromo area (located within Tengger Caldera) have learn to live with the threat of volcanic hazard since this volcano is categorized as an active volcano in Indonesia. During 2010, the eruption intensity increased yielding heavy ash fall and glowing rock fragments. A significant risk is also presented by mass movement which reaches areas up to 25 km from the crater. As a result of the 2010 eruption, 12 houses were destroyed, 25 houses collapsed and there were severe also effects on agriculture and the livestock sector. This paper focuses on understanding the interaction of Bromo volcanic eruption processes and their social responses. The specific aims are to 1) identify the 2010 eruption of Bromo 2) examine the human-volcano relationship within Bromo area in general, and 3) investigate the local knowledge related to hazard, risk perception and their adaptation strategies in specific. In-depth interviews with 33 informants from four districts nearest to the crater included local people and authorities were carried out. The survey focused on farmers, key persons (dukun), students and teachers in order to understand how people respond to Bromo eruption. The results show that the eruption in 2010 was unusual as it took continued for nine months, the longest period in Bromo history. The type of eruption was phreatomagmatic producing material dominated by ash to fine sand. This kind of sediment typically belongs to Tengger mountain eruptions which had produced vast explosions in the past. Furthermore, two years after the eruption, the interviewed people explained that local knowledge and their experiences with volcanic activity do not influence their risk perception. Dealing with this eruption, people in the Bromo area applied 'lumbung desa' (traditional saving systems) and mutual aid activity for surviving the volcanic eruption. Keywords: Human-environment system, local knowledge, risk perception, adaptation strategies, Bromo Volcano Indonesia

  3. Disentangling the eruption source parameters that control the climate effects of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Marshall, Lauren; Schmidt, Anja; Mann, Graham; Carslaw, Kenneth; Dhomse, Sandip; Haywood, Jim; Jones, Andy

    2016-04-01

    Climatic cooling in the 1-2 years following a major volcanic eruption does not scale linearly with the mass of SO2 injected into the atmosphere. The injection height of the emissions, the latitude of the volcano, the season and large scale atmospheric circulations, also influence the climatic response. Complex couplings exist between stratospheric chemistry and circulations, and aerosol induced heating and aerosol microphysical processes such as condensation and evaporation. As yet, there has been no systematic assessment of these relationships when considering different eruption source parameters. A series of simulations with a global composition-climate model with interactive stratospheric chemistry and aerosol microphysics are conducted, in which the eruption latitude and injection height are varied. Parameter combinations are chosen such that injections sample areas in the atmosphere where different chemical and dynamical influences are important (e.g. tropical vs. high latitude eruptions, injections near the tropopause vs. injections in the upper stratosphere). Each experiment is repeated for varying SO2 injection magnitudes. We focus on the analysis of aerosol properties such as the stratospheric aerosol optical depth, effective radius and heating rates, and resultant perturbations to radiative fluxes. Initial results demonstrate the non-linearity in the climatic response as the injection magnitude is increased. Future work will focus on disentangling the contribution of each parameter to the climatic response with additional simulations to investigate the effect of season and the Quasi Biennial Oscillation. Results will aid in the understanding of the impact of past, present and future volcanic eruptions. By analysing sulfate deposition to the polar ice caps, we will assess the uncertainty in, and validity of, the historic volcanic radiative forcing deduced from ice cores.

  4. 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.

  5. Quantifying the condition of eruption column collapse during explosive volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Koyaguchi, Takehiro; Suzuki, Yujiro

    2016-04-01

    During an explosive eruption, a mixture of pyroclasts and volcanic gas forms a buoyant eruption column or a pyroclastic flow. Generation of a pyroclastic flow caused by eruption column collapse is one of the most hazardous phenomena during explosive volcanic eruptions. The quantification of column collapse condition (CCC) is, therefore, highly desired for volcanic hazard assessment. Previously the CCC was roughly predicted by a simple relationship between magma discharge rate and water content (e.g., Carazzo et al., 2008). When a crater is present above the conduit, because of decompression/compression process inside/above the crater, the CCC based on this relationship can be strongly modified (Woods and Bower, 1995; Koyaguchi et al., 2010); however, the effects of the crater on CCC has not been fully understood in a quantitative fashion. Here, we have derived a semi-analytical expression of CCC, in which the effects of the crater is taken into account. The CCC depends on magma properties, crater shape (radius, depth and opening angle) as well as the flow rate at the base of crater. Our semi-analytical CCC expresses all these dependencies by a single surface in a parameter space of the dimensionless magma discharge rate, the dimensionless magma flow rate (per unit area) and the ratio of the cross-sectional areas at the top and the base of crater. We have performed a systematic parameter study of three-dimensional (3D) numerical simulations of eruption column dynamics to confirm the semi-analytical CCC. The results of the 3D simulations are consistent with the semi-analytical CCC, while they show some additional fluid dynamical features in the transitional state (e.g., partial column collapse). Because the CCC depends on such many parameters, the scenario towards the generation of pyroclastic flow during explosive eruptions is considered to be diverse. Nevertheless, our semi-analytical CCC together with the existing semi-analytical solution for the 1D conduit flow

  6. 2010 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; Herrick, Julie; Girina, O.A.; Chibisova, Marina; Rybin, Alexander; McGimsey, Robert G.; Dixon, Jim

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest or suspected unrest at 12 volcanic centers in Alaska during 2010. The most notable volcanic activity consisted of intermittent ash emissions from long-active Cleveland volcano in the Aleutian Islands. AVO staff also participated in hazard communication regarding eruptions or unrest at seven volcanoes in Russia as part of an ongoing collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  7. Regional-scale forcing of precipitation in selected modern volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Yim, W. W.-S.

    2009-04-01

    Major volcanic eruptions are known to lower the Earth's surface temperature but their regional-scale forcing of precipitation is poorly understood. In this presentation, three modern volcanic eruptions have been selected for investigation. The three eruptions are the February 1963 Agung eruption in Indonesia, the March 1982 El Chichón eruption in Mexico and the June 1991 Pinatubo eruption in the Philippines. Abnormally low annual rainfall was found in the southern China region during 1963 and 1991 respectively. Based on the total annual rainfall recorded at the Hong Kong Station, the rainfall was the driest and the tenth driest since record began in 1884 respectively. In contrast, abnormally high annual rainfall was found in southern China in 1982 with the Hong Kong Station recording the second wettest year since record began. Based on the pattern of rainfall observed, near-field major volcanic eruptions located in the Indonesian-Pacific gateway may lead to abnormally dry conditions in southern China through a shift of wind direction to predominantly offshore. On the other hand, major far-field volcanic eruptions in the eastern Pacific may give rise to abnormally wet conditions through the spread of the volcanic cloud across the globe. In the El Chichón eruption, the spread of volcanic cloud across the Pacific Ocean was tracked by satellite images. Heavy rainfall occurred when the volcanic cloud reached the coastal regions of southern China. Volcanic eruptions are therefore a possible causative factor in monsoonal variability.

  8. Exploring the Potential Impacts of Historic Volcanic Eruptions on the Contemporary Global Food System

    NASA Technical Reports Server (NTRS)

    Puma, Michael J.; Chon, S.; Wada, Y.

    2015-01-01

    A better understanding of volcanic impacts on crops is urgently needed, as volcanic eruptions and the associated climate anomalies can cause unanticipated shocks to food production. Such shocks are a major concern given the fragility of the global food system.

  9. Investigating the value of passive microwave observations for monitoring volcanic eruption source parameters

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario; Cimini, Domenico; Marzano, Frank

    2016-04-01

    Volcanic eruptions inject both gas and solid particles into the Atmosphere. Solid particles are made by mineral fragments of different sizes (from few microns to meters), generally referred as tephra. Tephra from volcanic eruptions has enormous impacts on social and economical activities through the effects on the environment, climate, public health, and air traffic. The size, density and shape of a particle determine its fall velocity and thus residence time in the Atmosphere. Larger particles tend to fall quickly in the proximity of the volcano, while smaller particles may remain suspended for several days and thus may be transported by winds for thousands of km. Thus, the impact of such hazards involves local as well as large scales effects. Local effects involve mostly the large sized particles, while large scale effects are caused by the transport of the finest ejected tephra (ash) through the atmosphere. Forecasts of ash paths in the atmosphere are routinely run after eruptions using dispersion models. These models make use of meteorological and volcanic source parameters. The former are usually available as output of numerical weather prediction models or large scale reanalysis. Source parameters characterize the volcanic eruption near the vent; these are mainly the ash mass concentration along the vertical column and the top altitude of the volcanic plume, which is strictly related to the flux of the mass ejected at the emission source. These parameters should be known accurately and continuously; otherwise, strong hypothesis are usually needed, leading to large uncertainty in the dispersion forecasts. However, direct observations during an eruption are typically dangerous and impractical. Thus, satellite remote sensing is often exploited to monitor volcanic emissions, using visible (VIS) and infrared (IR) channels available on both Low Earth Orbit (LEO) and Geostationary Earth Orbit (GEO) satellites. VIS and IR satellite imagery are very useful to monitor

  10. 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

  11. Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) project and a next-generation real-time volcano hazard assessment system

    NASA Astrophysics Data System (ADS)

    Takarada, S.

    2012-12-01

    The first Workshop of Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER1) was held in Tsukuba, Ibaraki Prefecture, Japan from February 23 to 24, 2012. The workshop focused on the formulation of strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis, and volcanic eruptions. More than 150 participants attended the workshop. During the workshop, the G-EVER1 accord was approved by the participants. The Accord consists of 10 recommendations like enhancing collaboration, sharing of resources, and making information about the risks of earthquakes and volcanic eruptions freely available and understandable. The G-EVER Hub website (http://g-ever.org) was established to promote the exchange of information and knowledge among the Asia-Pacific countries. Several G-EVER Working Groups and Task Forces were proposed. One of the working groups was tasked to make the next-generation real-time volcano hazard assessment system. The next-generation volcano hazard assessment system is useful for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is planned to be developed based on volcanic eruption scenario datasets, volcanic eruption database, and numerical simulations. Defining volcanic eruption scenarios based on precursor phenomena leading up to major eruptions of active volcanoes is quite important for the future prediction of volcanic eruptions. Compiling volcanic eruption scenarios after a major eruption is also important. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and styles, is important for the next-generation volcano hazard assessment system. The volcanic eruption database is developed based on past eruption results, which only represent a subset of possible future scenarios. Hence, different distributions from the previous deposits are mainly observed due to the differences in

  12. Lidar Observations of Stratospheric Clouds After Volcanic Eruption of Pinatubo

    NASA Technical Reports Server (NTRS)

    Sun, Jinhui; Qiu, Jinhuan; Xia, Qilin; Zhang, Jinding

    1992-01-01

    A very large increase of backscattered light from the stratospheric aerosol layer was observed by using a ruby laser in Beijing (39 degrees 54 minutes N, 116 degrees 27 minutes E) from the end of July 1991 to March 1992. It was concluded that this increase was almost certainly due to the volcanic eruption of Mt. Pinatubo in the Philippines in June 1991. The measuring instruments used are described. Information is given in graphical form for vertical profiles, fluctuation of the maximum backscattering ratio above 20 km during the nine month period, and the time variation of the integrated backscattering coefficient at a height of 15 to 30 km.

  13. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Hao, Zhixin; Sun, Di

    2016-04-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after tropical volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport,therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  14. The large volcanic eruptions at different latitude bands and patterns of winter temperature changes over China

    NASA Astrophysics Data System (ADS)

    Sun, D.; Hao, Z.; Zheng, J.

    2015-12-01

    Based on the chronology of 29 large volcanic eruptions events (Volcanic Explosivity Index≥4) since 1951 and gridded temperature dataset from China Meteorological Data Sharing Service System, we identified the patterns of winter temperature changes over China after the large volcanic eruptions, comparing with the mean temperature within the five years before, then we analyzed the related dynamic mechanisms of different patterns by NCEP reanalysis data and model output data from Community Earth System Model (CESM). The results showed that the winter temperature decreased more than 1°C in East China after volcanic eruptions on middle-lower latitudes and equatorial bands. After volcanic eruptions on different latitudes, the temperature spatial patterns were summarized as two types, which included that temperature was cooling centered on Northeast and warming in Tibets, and its opposite pattern. The first pattern was usually detected after equatorial volcanic eruptions in spring/summer and it also appeared after volcanic eruptions on high latitudes in spring/autumn. After middle-lower latitude volcanic eruptions, the variation of geopotential height on 500hPa showed that the positive anomaly was existed at the East of Ural mountain, which caused the temperature decreased in Northwest , Central East and Southeast when east asian trough was intensified. After high latitudes volcanic eruptions, the zonal circulation was more obvious at middle latitudes, the cold air was not easy to transport therefore winter temperature increased in China except for the Yangtze River Basin. The result of full forcing experiments by CESM showed that temperature decreased at most regions after large volcanic eruptions on equatorial /high bands, and troughs and wedges were developed on 500 hPa. The variation of geopotential height was nearly reversed after volcanic eruptions on high latitudes, only the temperature of Tibetan Plateau decreased. But how the variation of geopotential height

  15. Eruptive History of the Rhyolitic Guangoche Volcano, Los Azufres Volcanic Field, Central Mexico

    NASA Astrophysics Data System (ADS)

    Rangel Granados, E.; Arce, J. L.; Macias, J. L.; Layer, P. W.

    2014-12-01

    Guangoche is a rhyolitic and polygenetic volcano with a maximum elevation of 2,760 meters above sea level. It is situated to the southwest of the Los Azufres Volcanic Field (LAVF), in the central sector of the Trans-Mexican Volcanic Belt. Guangoche volcano is the youngest volcano described within the LAVF. It shows a horseshoe shaped crater open to the south, with a central lava dome. Its eruptive history during late Pleistocene has been intense with six explosive eruptions that consists of: 1) A southwards sector collapse of the volcano that generated a debris avalanche deposit with megablocks of heterogenous composition; 2) A plinian-type eruption that generated a pumice fall deposit and pyroclastic density currents by column collapse at 30.6 ka; 3) A plinian-type eruption "White Pumice Sequence" (29 ka) that developed a 22-km-high eruptive column, with a MDR of 7.0 x 107 kg/s (vol. = 0.53 km3); 4) A dome-destruction event, "Agua Blanca Pyroclastic Sequence" at 26.7 ka, that deposited a block-and-ash flow deposit; 5) A subplinian-plinian type eruption "Ochre Pyroclastic Sequence" (<26 ka) with an important initial phreatomagmatic phase, that generated pyroclastic density currents and pumice fallouts. The subplinian-plinian event generated a 16-km-high eruptive column, with a MDR of 1.9 x 107 kg/s, and magma volume of 0.38 km3; 6) The eruptive history ended with a subplinian eruption (<<26 ka), that generated a multilayered fall deposit, that developed a 11-km-high eruptive column, with a MDR of 2.9 x 106 kg/s and a magma volume of 0.26 km3. Volcanic activity at Guangoche volcano has been intense and future activity should not be discarded. Unfortunately, the last two events have not been dated yet. Guangoche rhyolitic magma is characterized by low-Ba contents suggesting crystal mush extraction for their genesis.

  16. Transient changes in bacterioplankton communities induced by the submarine volcanic eruption of El Hierro (Canary Islands).

    PubMed

    Ferrera, Isabel; Arístegui, Javier; González, José M; Montero, María F; Fraile-Nuez, Eugenio; Gasol, Josep M

    2015-01-01

    The submarine volcanic eruption occurring near El Hierro (Canary Islands) in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1-V3 regions for Bacteria and V3-V5 for Archaea) to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012). Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells) of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70-200 m), coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index) decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria). Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer observed. PMID

  17. Transient Changes in Bacterioplankton Communities Induced by the Submarine Volcanic Eruption of El Hierro (Canary Islands)

    PubMed Central

    Ferrera, Isabel; Arístegui, Javier; González, José M.; Montero, María F.; Fraile-Nuez, Eugenio; Gasol, Josep M.

    2015-01-01

    The submarine volcanic eruption occurring near El Hierro (Canary Islands) in October 2011 provided a unique opportunity to determine the effects of such events on the microbial populations of the surrounding waters. The birth of a new underwater volcano produced a large plume of vent material detectable from space that led to abrupt changes in the physical-chemical properties of the water column. We combined flow cytometry and 454-pyrosequencing of 16S rRNA gene amplicons (V1–V3 regions for Bacteria and V3–V5 for Archaea) to monitor the area around the volcano through the eruptive and post-eruptive phases (November 2011 to April 2012). Flow cytometric analyses revealed higher abundance and relative activity (expressed as a percentage of high-nucleic acid content cells) of heterotrophic prokaryotes during the eruptive process as compared to post-eruptive stages. Changes observed in populations detectable by flow cytometry were more evident at depths closer to the volcano (~70–200 m), coinciding also with oxygen depletion. Alpha-diversity analyses revealed that species richness (Chao1 index) decreased during the eruptive phase; however, no dramatic changes in community composition were observed. The most abundant taxa during the eruptive phase were similar to those in the post-eruptive stages and to those typically prevalent in oceanic bacterioplankton communities (i.e. the alphaproteobacterial SAR11 group, the Flavobacteriia class of the Bacteroidetes and certain groups of Gammaproteobacteria). Yet, although at low abundance, we also detected the presence of taxa not typically found in bacterioplankton communities such as the Epsilonproteobacteria and members of the candidate division ZB3, particularly during the eruptive stage. These groups are often associated with deep-sea hydrothermal vents or sulfur-rich springs. Both cytometric and sequence analyses showed that once the eruption ceased, evidences of the volcano-induced changes were no longer observed

  18. Ionospheric disturbances by volcanic eruptions by GNSS-TEC: Comparison between Vulcanian and Plinian eruptions

    NASA Astrophysics Data System (ADS)

    Nakashima, Y.; Heki, K.; Takeo, A.; Cahyadi, M. N.; Aditiya, A.

    2014-12-01

    Acoustic waves from volcanic eruptions are often observed as infrasound in near fields. Part of them propagate upward and disturb the ionosphere, and can be observed in Total Electron Content (TEC) data derived by Global Navigation Satellite System (GNSS) receivers. In the past, Heki (2006 GRL) detected ionospheric disturbances by the 2004 explosion of the Asama Volcano, central Japan, and Dautermann et al. (2009 JGR) studied the 2003 eruption of the Soufriere Hills volcano in Montserrat, West Indies. Here we present new examples, and try to characterize such disturbances. We first show TEC disturbances by the 2014 February Plinian eruption (VEI 4) of the Kelud volcano, East Java, Indonesia (Figure), observed with a regional GNSS network.The 2014 Kelud eruption broke a lava dome made by 2007 eruption and created a new creator. Significant disturbances were detected with four GPS and two GLONASS satellites, and the wavelet analyses showed that harmonic oscillations started at ~16:25 UT and continued nearly one hour. The frequency of the oscillation was ~3.8 mHz, which coincides with the atmospheric fundamental mode. We also confirmed concentric wavefronts, moving outward by ~0.8m/sec (stronger signals on the northern side). These features are similar to the 2003 Soufriere Hills case, although the signals in the present Kelud case is much clearer. Next, we compare them with ionospheric disturbances by Vulcanian explosions that occurred recently in Japan, i.e. the 2004 Asama case and the 2009 Sakurajima, and the 2011 Shin-moedake eruptions. They are characterized with one-time N-shaped disturbances possibly excited by the compression of the air above the vents. On the other hand, data from nearby seismometers suggested that atmospheric oscillations of various frequencies were excited by this continuous Plinian eruption. Part of such oscillations would have grown large due to atmospheric resonance.

  19. 2011 volcanic activity in Alaska: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Maharrey, J. Zebulon; Neal, Christina A.

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near three separate volcanic centers in Alaska during 2011. The year was highlighted by the unrest and eruption of Cleveland Volcano in the central Aleutian Islands. AVO annual summaries no longer report on activity at Russian volcanoes.

  20. Eruption chronology of Ciomadul, a long dormant dacitic volcanic system in the Eastern Carpathians

    NASA Astrophysics Data System (ADS)

    Molnár, Kata; Harangi, Szabolcs; Dunkl, István; Lukács, Réka; Kiss, Balázs; Schmitt, Axel K.; Seghedi, Ioan

    2016-04-01

    During the last decade, the zircon (U-Th)/He geochronology has become a promising method for dating eruption histories even in case of very young (Quaternary) volcanic products. It is proved to be particularly applicable when other dating methods such as radiocarbon, K/Ar, and 40Ar/39Ar techniques encounter analytical or interpretational difficulties often caused by a lack of appropriate materials for dating. Zircon (U-Th)/He method can be used to infer the date of the rapid cooling of the erupted magma, i.e. the eruption age. However, when the crystals formed less than ~350 ka, correction for U-series disequilibrium is necessary. The effect of the secular disequilibrium can be corrected by the U-Th zircon dates, which provides additional information also about the timescale of the magma storage. Here, we provide a detailed zircon (U-Th)/He dating approach to refine the eruption chronology of the Ciomadul dacite volcanic complex, found at the East Carpathians, eastern-central Europe. It is characterized by an intermittent precursor lava dome activity with extrusion of 0.1-0.6 km3 dacitic magma, followed by the build-up of a massive lava dome complex with two explosion craters. The erupted products are fairly homogeneous dacite with similar mineral cargo. During the field campaigns we focused on the volcanic products of the Ciomadul lava dome complex and sampled all the known localities to cover the whole volcanic period and avoid sampling bias. According to the new (U-Th)/He results the precursor lava domes were formed between ~1000 and 300 ka, during several intermittent eruption events which were separated by long repose times: Bába Laposa: 950±50 ka, Delaul Mare: 840±12 ka, Puturosul: 710±50 ka, Bálványos: 580±20 ka and Turnul Apor: 330±40 ka. After another long quiescence, volcanic activity renewed at about 200 ka and became more productive. Numerous lava domes were developed between ca. 160 and 100 ka, which form the 10-12 km3 central lava dome edifice

  1. NO2 column changes induced by volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Johnston, Paul V.; Keys, J. Gordon; Mckenzie, Richard L.

    1994-01-01

    Nitrogen dioxide slant column amounts measured by ground-based remote sensing from Lauder, New Zealand (45 deg S) and Campbell Island (53 deg S) during the second half of 1991 and early 1992 show anomalously low values that are attributed to the effects of volcanic eruptions. It is believed that the eruptions of Mount Pinatubo in the Philippines in June 1991 and possibly Mount Hudson in Chile in August 1991 are responsible for the stratospheric changes, which first became apparent in July 1991. The effects in the spring of 1991 are manifested as a reduction in the retrieved NO2 column amounts from normal levels by 35 to 45 percent, and an accompanying increase in the overnight decay of NO2. The existence of an accurate long-term record of column NO2 from the Lauder site enables us to quantify departures from the normal seasonal behavior with some confidence. Simultaneous retrievals of column ozone agree well with Dobson measurements, confirming that only part of the NO2 changes can be attributed to a modification of the scattering geometry by volcanic aerosols. Other reasons for the observed behavior are explored, including the effects of stratospheric temperature increases resulting from the aerosol loading and the possible involvement of heterogeneous chemical processes.

  2. Detection from Space of Active Volcanism on Earth and, Potentially, on Venus and Rocky Exoplanets

    NASA Astrophysics Data System (ADS)

    Mouginis-Mark, P. J.

    2015-05-01

    Volcanic eruptions (lava flows, lava lakes, and explosive activity) on Earth have been monitored from space for >3 decades. Such observations are extrapolated to understand how volcanic activity on Venus and rocky exoplanets may be detected.

  3. Katmai volcanic cluster and the great eruption of 1912

    USGS Publications Warehouse

    Hildreth, W.; Fierstein, J.

    2000-01-01

    In June 1912, the world's largest twentieth century eruption broke out through flat-lying sedimentary rocks of Jurassic age near the base of Trident volcano on the Alaska Peninsula. The 60 h ash-flow and Plinian eruptive sequence excavated and subsequently backfilled with ejecta a flaring funnel-shaped vent since called Novarupta. The vent is adjacent to a cluster of late Quaternary stratocones and domes that have released about 140 km3 of magma in the past 150 k.y. Although the 1912 vent is closest to the Trident group and is also close to Mageik and Griggs volcanoes, it was the summit of Mount Katmai, 10 km east of Novarupta, that collapsed during the eruption to form a 5.5 km3 caldera. Many earthquakes, including 14 in the range M 6-7, took place during and after the eruption, releasing 250 times more seismic energy than the 1991 caldera-forming eruption of the Philippine volcano, Pinatubo. The contrast in seismic behavior may reflect the absence of older caldera faults at Mount Katmai, lack of upward (subsidence opposing) magma flow owing to lateral magma withdrawal in 1912, and the horizontally stratified structure of the thick shale-rich Mesozoic basement. The Katmai caldera compensates for only 40% of the 13 km3 of 1912 magma erupted, which included 7-8 km3 of slightly zoned high-silica rhyolite and 4.5 km3 of crystal-rich dacite that grades continuously into 1 km3 of crystal-rich andesite. We have now mapped, sampled, and studied the products of all 20 components of the Katmai volcanic cluster. Pyroxene dacite and silicic andesite predominate at all of them, and olivine andesite is also common at Griggs, Katmai, and Trident volcanoes, but basalt and rhyodacite have erupted only at Mount Katmai. Rhyolite erupted only in 1912 and is otherwise absent among Quaternary products of the cluster. Pleistocene products of Mageik and Trident and all products of Griggs are compositionally distinguishable from those of 1912 at Novarupta. Holocene products of Mount

  4. Eruptions at Chaos Crags, Lassen Volcanic National Park, California

    SciTech Connect

    Heiken, G.; Eichelberger, J.C.

    1980-05-01

    Chaos Crags are a group of silicic lava domes and associated tephra deposits composed of intermediate and silicic lavas on the edge of the central plateau of Lassen Volcanic National Park, California. The plateau coincides with a negative gravity anomaly interpreted as a large silicic magma reservoir. About 0.15 km/sup 3/ of rhyodacitic pyroclastic flows were erupted 1100 years ago from vents beneath the present Crags and flowed for 21 km down the valleys of Lost and Manzanita Creeks. Pumice pyroclasts in the flows are characterized by high phenocryst content and low vesicularity. These eruptions were followed by the extrusion of 1.25 km/sup 3/ of dacitic lava as a stubby flow and three-lobed dome. The tephra and lava appear to be products of intrusion of mostly liquid high-alumina basalt into a large, partially crystallized rhyolitic magma body with subsequent mixing. The earliest tephra contain only a minor basaltic component while the youngest portion of the Crags contain approximately 20%. This change with time reflects either a vertical zonation in the magma inherited from the mixing event or a continued admixing of basaltic magma within the chamber during the span of eruptive period.

  5. Quantifying the impact of moderate volcanic eruptions on the stratosphere

    NASA Astrophysics Data System (ADS)

    Lurton, Thibaut; Jégou, Fabrice; Berthet, Gwenaël; Renard, Jean-Baptiste; Vignelles, Damien; Bègue, Nelson; Portafaix, Thierry; Bencherif, Hassan; Couté, Benoît; Duverger, Vincent; Payen, Guillaume; Metzger, Jean-Marc; Posny, Françoise

    2016-04-01

    We have investigated the impact of two recent moderate volcanic eruptions upon the sulphur dioxide and sulphate loading in the stratosphere, with the use of the CESM numerical global model. Through the use of the WACCM/CARMA module in CESM, which provides with a comprehensive modelling of the sulphur cycle, and at a ˜2° spatial resolution, we have investigated the impacts of the eruptions of the Kelud (13 February 2014, 7° S, 112° E) and Calbuco (22 April 2015, 41° S, 72° W) volcanoes on the lower stratosphere. The input SO2 quantities and altitudes of injection were estimated from satellite observations, and correspond in both cases to several hundreds of kT of SO2 injected directly at upper troposphere/lower stratosphere heights, over a few kilometres of altitude span. Our results have been compared with satellite measurements, from IASI for SO2, and the CALIOP space-borne lidar for aerosols. We also provide cross-comparisons with in-situ measurements performed above La Réunion Island (21° S, 55° E), first comparing our simulation results to the data obtained through the launch of a balloon-borne light optical aerosol counter (LOAC), and also by cross-comparison with in-situ lidar measurements. To investigate the role of dynamical barriers around those volcanic events, our simulations have been run using two different sets of meteorological forcing data (namely MERRA vs. ERA-Interim), which can differ in that respect, especially regarding the vertical advection at tropical latitudes. Our overall aim is to assess the impact of such moderate eruptions over the lower stratosphere, on the one hand chemically, and on the other hand in terms of radiative effects.

  6. Volcanic inflation of Axial Seamount since the 1998 eruption

    NASA Astrophysics Data System (ADS)

    Nooner, S. L.; Chadwick, W.

    2010-12-01

    Since 2000, ambient seawater pressure has been precisely measured at five seafloor benchmarks inside the summit caldera at Axial Seamount in order to measure their relative depth and monitor volcanic inflation that has been occurring since an eruption in 1998. A remotely operated vehicle has been used to deploy a mobile pressure recorder (MPR) in campaign-style surveys, with additional seawater pressure data collected at the caldera center with multiyear deployments of continuously recording bottom pressure recorders (BPRs). Our previous measurements at Axial Seamount have shown steady inflation of the caldera center through 2007 and the spatial pattern of uplift has been consistent with magma storage in a shallow reservoir underlying the caldera at a depth of 3.5 km. This is the only location in the world where long-term monitoring of volcanic inflation has been accomplished at a submarine volcano. Here we present the results of new pressure data (both MPR and BPR) collected during a cruise on board the R/V Thomas Thompson in August-September 2010 and using the Jason ROV. Three years have passed since the previous survey, providing enough time to distinguish between two alternative models of inflation and magma recharge for the volcano. This allows us to refine our forecast for the next eruption at Axial and estimate total uplift that has occurred since the 1998 eruption. During the 2010 survey we also deployed new concrete benchmarks to replace our original galvanized steel benchmarks. The new benchmarks are larger and much heavier, and we expect them to be much more durable and stable over long time periods and help keep measurement errors as small as possible. We installed a sixth benchmark at a new site within the caldera, near the Ashes vent field, which will help constrain our modeling of the inflation signal in future years.

  7. The feeder system for the 2014 fissure eruption at Holuhraun, Bárðarbunga volcanic system, Iceland: Geodetic and seismic constraints on subsurface activity in the area north of the Vatnajökull ice cap

    NASA Astrophysics Data System (ADS)

    Dumont, Stéphanie; Parks, Michelle; Sigmundsson, Freysteinn; Hooper, Andy; Hreinsdóttir, Sigrun; Ófeigsson, Benedikt; Spaans, Karsten; Vogfjörd, Kristin; Jónsdóttir, Kristín; Hensch, Martin; Gudmundsson, Gunnar; Rafn Heimisson, Elias; Drouin, Vincent; Árnadóttir, Thóra; Pedersen, Rikke; Rut Hjartardóttir, Ásta; Magnússon, Eyjólfur

    2015-04-01

    An intense earthquake swarm began on 16 August 2014 at Bárðarbunga volcano under the Vatnajökull ice cap in Central Iceland. It marked the beginning of an intrusive activity, with a dyke propagating over 45 km northward. Such major magmatic activity has not been observed for the last three decades in Iceland, since the Krafla rifting episode 1975-1984. The dyke propagation stopped 15 days after the onset of the seismic activity, with the dyke distal end in the Holuhraun plain north of the Vatnajökull ice cap. A small 4 hour eruption marked the beginning of extrusive activity. A new fissure eruption opened up on 31 August at the northern dyke tip, with lava fountaining and feeding extensive lava flows. In January 2014 the surface covered by the lava had exceeded 80 km2, and the eruption activity does not show significant decline. We have carried out interferometric analysis of SAR data (InSAR) since the onset of the unrest. X-band satellite images from COSMO-SkyMed and TerraSAR-X satellites were acquired and analyzed to map ground surface deformation associated with the dyke emplacement. Despite most of the dyke propagation occurring under several hundreds meters of ice, the last 10 km were outside the ice cap, allowing better characterisation of the dyke-induced deformation. Here we focus on the deformation in the Holuhraun plain, in order to better understand the link between the surface deformation detected in the vicinity of the dyke by InSAR as well as GPS measurements, and the eruptive activity. The regular SAR acquisitions made over the Holuhraun area since the beginning of the unrest offer a unique opportunity to better understand the evolution of the intrusion feeding the fissure eruption. For that purpose, we focus on the faults and fissures forming the graben borders on the glacier as well as in the Holuhraun plain, initially mapped using high-resolution radar images, acquired by airborne radar. We extract movement along and perpendicular to these

  8. The mechanisms of fine particle generation and electrification during Mount St. Helens volcanic eruption

    NASA Technical Reports Server (NTRS)

    Cheng, R. J.

    1982-01-01

    Microscopical investigation of volcanic ash collected from ground stations during Mount St. Helens eruptions reveal a distinctive bimodel size distribution with high concentrations of particle ranges at (1) 200-100 microns and (2) 20-0.1 microns. Close examination of individual particles shows that most larger ones are solidified magma particles of porous pumice with numerous gas bubbles in the interior and the smaller ones are all glassy fragments without any detectable gas bubbles. Elemental analysis demonstrates that the fine fragments all have a composition similar to that of the larger pumice particles. Laboratory experiments suggest that the formation of the fine fragments is by bursting of glassy bubbles from a partially solidified surface of a crystallizing molten magma particle. The production of gas bubbles is due to the release of absorbed gases in molten magma particles when solubility decreases during phase transition. Diffusion cloud chamber experiments strongly indicate that sub-micron volcanic fragments are highly hygroscopic and extremely active as cloud condensation nuclei. Ice crystals also are evidently formed on those fragments in a supercooled (-20 C) cloud chamber. It has been reported that charge generation from ocean volcanic eruptions is due to contact of molten lava with sea water. This seems to be insufficient to explain the observed rapid and intense lightning activities over Mount St. Helens eruptions. Therefore, a hypothesis is presented here that highly electrically charged fine solid fragments are ejected by bursting of gas bubbles from the surface of a crystallizing molten magma particles.

  9. The effect of volcanic eruptions on global precipitation

    NASA Astrophysics Data System (ADS)

    Iles, Carley E.; Hegerl, Gabriele C.; Schurer, Andrew P.; Zhang, Xuebin

    2013-08-01

    We examine robust features of the global precipitation response to 18 large low-latitude volcanic eruptions using an ensemble of last millennium simulations from the climate model HadCM3. We then test whether these features can be detected in observational land precipitation data following five twentieth century eruptions. The millennium simulations show a significant reduction in global mean precipitation following eruptions, in agreement with previous studies. Further, we find that the response over ocean remains significant for around 5 years and matches the timescale of the near-surface air temperature response. In contrast, the land precipitation response remains significant for 3 years and reacts faster than land temperature, correlating with aerosol optical depth and a reduction in land-ocean temperature contrast. In the tropics, areas experiencing posteruption drying coincide well with climatologically wet regions, while dry regions get wetter on average, but there changes are spatially heterogeneous. This pattern is of opposite sign to, but physically consistent with, projections under global warming. A significant reduction in global mean and wet tropical land regions precipitation is also found in response to twentieth century eruptions in both the observations and model masked to replicate observational coverage, although this is not significant for the observed wet regions response in boreal summer. In boreal winter, the magnitude of this global response is significantly underestimated by the model; the discrepancy originating from the wet tropical regions although removing the influence of ENSO improves agreement. The modeled precipitation response is detectable in the observations in boreal winter but marginal in summer.

  10. Degassing during quiescence as a trigger of magma ascent and volcanic eruptions

    PubMed Central

    Girona, Társilo; Costa, Fidel; Schubert, Gerald

    2015-01-01

    Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. The hyperactivity of these volcanoes results from frequent pressurizations of the shallow magma plumbing system, which in most cases are thought to occur by the ascent of magma from deep to shallow reservoirs. However, the driving force that causes magma ascent from depth remains unknown. Here we demonstrate that magma ascent can be triggered by the passive release of gas during quiescence, which induces the opening of pathways connecting deep and shallow magma reservoirs. This top-down mechanism for volcanic eruptions contrasts with the more common bottom-up mechanisms in which magma ascent is only driven by processes occurring at depth. A cause-effect relationship between passive degassing and magma ascent can explain the fact that repose times are typically much longer than unrest times preceding eruptions, and may account for the so frequent unrest episodes of persistently degassing volcanoes. PMID:26666396

  11. Degassing during quiescence as a trigger of magma ascent and volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Girona, Társilo; Costa, Fidel; Schubert, Gerald

    2015-12-01

    Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. The hyperactivity of these volcanoes results from frequent pressurizations of the shallow magma plumbing system, which in most cases are thought to occur by the ascent of magma from deep to shallow reservoirs. However, the driving force that causes magma ascent from depth remains unknown. Here we demonstrate that magma ascent can be triggered by the passive release of gas during quiescence, which induces the opening of pathways connecting deep and shallow magma reservoirs. This top-down mechanism for volcanic eruptions contrasts with the more common bottom-up mechanisms in which magma ascent is only driven by processes occurring at depth. A cause-effect relationship between passive degassing and magma ascent can explain the fact that repose times are typically much longer than unrest times preceding eruptions, and may account for the so frequent unrest episodes of persistently degassing volcanoes.

  12. Degassing during quiescence as a trigger of magma ascent and volcanic eruptions.

    PubMed

    Girona, Társilo; Costa, Fidel; Schubert, Gerald

    2015-01-01

    Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. The hyperactivity of these volcanoes results from frequent pressurizations of the shallow magma plumbing system, which in most cases are thought to occur by the ascent of magma from deep to shallow reservoirs. However, the driving force that causes magma ascent from depth remains unknown. Here we demonstrate that magma ascent can be triggered by the passive release of gas during quiescence, which induces the opening of pathways connecting deep and shallow magma reservoirs. This top-down mechanism for volcanic eruptions contrasts with the more common bottom-up mechanisms in which magma ascent is only driven by processes occurring at depth. A cause-effect relationship between passive degassing and magma ascent can explain the fact that repose times are typically much longer than unrest times preceding eruptions, and may account for the so frequent unrest episodes of persistently degassing volcanoes. PMID:26666396

  13. Degassing during quiescence as a trigger of magma ascent and volcanic eruptions.

    PubMed

    Girona, Társilo; Costa, Fidel; Schubert, Gerald

    2015-12-15

    Understanding the mechanisms that control the start-up of volcanic unrest is crucial to improve the forecasting of eruptions at active volcanoes. Among the most active volcanoes in the world are the so-called persistently degassing ones (e.g., Etna, Italy; Merapi, Indonesia), which emit massive amounts of gas during quiescence (several kilotonnes per day) and erupt every few months or years. The hyperactivity of these volcanoes results from frequent pressurizations of the shallow magma plumbing system, which in most cases are thought to occur by the ascent of magma from deep to shallow reservoirs. However, the driving force that causes magma ascent from depth remains unknown. Here we demonstrate that magma ascent can be triggered by the passive release of gas during quiescence, which induces the opening of pathways connecting deep and shallow magma reservoirs. This top-down mechanism for volcanic eruptions contrasts with the more common bottom-up mechanisms in which magma ascent is only driven by processes occurring at depth. A cause-effect relationship between passive degassing and magma ascent can explain the fact that repose times are typically much longer than unrest times preceding eruptions, and may account for the so frequent unrest episodes of persistently degassing volcanoes.

  14. Active Eruptions in the NE Lau Basin

    NASA Astrophysics Data System (ADS)

    Resing, J. A.; Embley, R. W.

    2009-12-01

    NE Lau Response Team: K Rubin, E Baker, J Lupton, M Lilley, T Shank, S Merle, R Dziak, T Collasius (Jason 2 Expedition Leader), N Buck, T Baumberger, D Butterfield, D Clague, D Conlin, J Cowen, R Davis, L Evans, J Huber, M Keith, N Keller, P Michael, E Podowski, A-L Reysenbach, K Roe, H Thomas, S Walker. During a May 2009 cruise to W Mata volcano in the NE Lau Basin, we made the first observations of an active eruption on the deep-sea floor. The cruise was organized after volcanic activity was detected at two sites (W Mata volcano and NE Lau Spreading Center, NELSC) during a Nov. 2008 NOAA-PMEL expedition. At that time, both sites had elevated H2 concentrations and volcaniclastic shards in the hydrothermal plumes. Moored hydrophone data since Jan 2009 indicate that the activity at W Mata has been continuous between these expeditions. Results of our cruise and other work suggest that the NE Lau Basin hosts an unusually high level of magmatic activity, making it an ideal location to study the effects of magmatic processes on hydrothermal activity and associated ecosystems. W Mata was visited with 5 ROV Jason 2 dives and 2 dives with the MBARI autonomous mapping vehicle in May 2009. It was actively erupting at the 1200 m deep summit during each, so a hydrophone was deployed locally to collect acoustic data. Ship and shore-based analysis of HD video, molten lava, rocks, sediments, hot spring waters, and micro- and macro biological specimens collected by Jason 2 have provided a wealth of data. The eruption itself was characterized by extrusion of red, molten lava, extensive degassing, formation of large magma bubbles, explosive pyroclast ejection, and the active extrusion of pillow lavas. The erupting magmas are boninite, a relatively rare magma type found only at convergent margins. The hydrothermal fluids are generally acidic and all diffuse fluids collected were microbially active, even those at pH <3. W Mata was host to shrimp similar to those found at several other

  15. Character and timing of recent eruptions of the Tatun Volcanic Group, Northern Taiwan

    NASA Astrophysics Data System (ADS)

    Belousova, Marina; Belousov, Alexander; Chen, Chang-Hwa; Zellmer, Georg

    2010-05-01

    The quaternary dominantly andesitic Tatun Volcanic Group (TVG) occupies 400 km² in the northern part of Taiwan Island. The group has more than 20 well-preserved volcanic edifices, multiple hot springs and fumaroles as hot as 120°C with magmatic isotopic signatures. Local seismic network has registered shallow volcano-tectonic earthquakes in the area. The TVG is surrounded by densely populated areas, the largest of which is Taipei City (7 million people), as well as by multiple industrial factories and two nuclear power plants. Therefore, the question about timing and styles of the most recent TVG eruptions is important. We report results of our investigations of TVG physical volcanology, with focus on pyroclastic stratigraphy and eruption dynamics. For the most recent TVG eruptions were common long-term extrusions of crystal-rich, viscous lava. The eruptions formed dominantly monogenetic plug domes, coulees, and lava flows. The domes have heights of 150-400 m, base diameters of 0.5-2 km, and volumes of 0.05-0.3 km³. The nine best-preserved TVG lava flows have thicknesses of 80-150 m, lengths of 1-5.6 km, and volumes of 0.07-0.6 km³. Based on morphology of the largest lava flow we estimated an effusion rate of 6.4 m³/s, eruption duration of 1100 days, lava front speed of 2-3 m/hour. The only pyroclastic edifice of the Tatun group is a tephra ring ~500 m in diameter and 40 m high formed by plinian eruption. Apart from that, few non-reworked pyroclastic deposits are currently preserved at TVG. The available data have shown that the explosive activity of TVG was weak-to-mild, but rather diverse with deposition of fallout tephra, base surges, and pyroclastic flows. Fallout deposits are represented mostly by well-sorted, crystal-rich ash layers (Md 1.0-3.4 phi, sorting 0.9-2.4 phi) left by Vulcanian-type activity. Deposits of pumice fallout (Md -4-(-2.5) phi, sorting 1.2-2.4 phi) from Plinian eruptions are less common. Many of the eruptions show evidence of water

  16. Impacts of volcanic eruptions and geoengineering on Arctic climate

    NASA Astrophysics Data System (ADS)

    Berdahl, Mira

    Stratospheric aerosols can produce large radiative forcing and climate response, often amplified in the Arctic. Here I study the Arctic response to natural (volcanic eruptions) and potential anthropogenic (geoengineering) stratospheric sulfate aerosols. I use a regional climate model and global climate model output from two modeling intercomparison projects. First, I investigate the relative impacts of changes in radiation and advection on snow extent over Baffin Island with the Weather Research and Forecasting model. Model results show it is possible to suddenly lower the snowline by amounts comparable to those seen during the Little Ice Age with an average temperature decrease of --3.9 +/- 1.1 K from present. Further, sea ice expansion following large volcanic eruptions would have significant affects on inland temperatures, especially in the fall. Next, I analyze Last Millennium simulations from the Paleoclimate Modeling Intercomparison Project 3 to assess whether state-of-the-art global climate models produce sudden changes and persistence of cold conditions after large volcanic eruptions as inferred by geological records and previous climate modeling. North Atlantic sea ice and Baffin Island snow cover showed large-scale expansion in the simulations, but none of the models produced significant centennial-scale effects. Warm Baffin Island summer climates stunt snow expansion in some models completely, and model topography misses the critical elevations that could sustain snow on the island. This has critical consequences for ice and snow formation and persistence in regions such as the Arctic where temperatures are near freezing and small temperature changes affect the state of water. Finally, I analyze output from the Geoengineering Modeling Intercomparison Project to examine whether geoengineering by injection of sulfate aerosols into the lower stratosphere prevents the demise of minimum annual sea ice extent, or slows spring snow cover loss. Despite

  17. New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy)

    USGS Publications Warehouse

    de Vivo, B.; Rolandi, G.; Gans, P.B.; Calvert, A.; Bohrson, W.A.; Spera, F.J.; Belkin, H.E.

    2001-01-01

    The ∼ 150 km3 (DRE) trachytic Campanian Ignimbrite, which is situated north-west of Naples, Italy, is one of the largest eruptions in the Mediterranean region in the last 200 ky. Despite centuries of investigation, the age and eruptive history of the Campanian Ignimbrite is still debated, as is the chronology of other significant volcanic events of the Campanian Plain within the last 200–300 ky. New 40Ar/39Ar geochronology defines the age of the Campanian Ignimbrite at 39.28 ± 0.11 ka, about 2 ky older than the previous best estimate. Based on the distribution of the Campanian Ignimbrite and associated uppermost proximal lithic and polyclastic breccias, we suggest that the Campanian Ignimbrite magma was emitted from fissures activated along neotectonic Apennine faults rather than from ring fractures defining a Campi Flegrei caldera. Significantly, new volcanological, geochronological, and geochemical data distinguish previously unrecognized ignimbrite deposits in the Campanian Plain, accurately dated between 157 and 205 ka. These ages, coupled with a xenocrystic sanidine component > 315 ka, extend the volcanic history of this region by over 200 ky. Recent work also identifies a pyroclastic deposit, dated at 18.0 ka, outside of the topographic Campi Flegrei basin, expanding the spatial distribution of post-Campanian Ignimbrite deposits. These new discoveries emphasize the importance of continued investigation of the ages, distribution, volumes, and eruption dynamics of volcanic events associated with the Campanian Plain. Such information is critical for accurate assessment of the volcanic hazards associated with potentially large-volume explosive eruptions in close proximity to the densely populated Neapolitan region.

  18. Explosive eruption of rhyodacitic magma at the Cordón-Caulle volcanic complex, southern Chile

    NASA Astrophysics Data System (ADS)

    Castro, J. M.; Schipper, C.

    2011-12-01

    After lying dormant for decades, the Cordón-Caulle volcanic complex (CCVC) reactivated again on 4 June, 2011 with an explosive eruption that produced a sustained vertical ash column reaching roughly 14,000 m a.s.l. This explosive phase produced a tephra plume that dispersed E-SE across the Chilean Patagonia into Argentina, and within a week encircled the globe prompting widespread disruption to air traffic and several airport closures. After about 3 weeks of fluctuating explosive activity, a lava flow began effusing from the same vent as the initial activity. We analyzed pumice and ash samples of the Plinian fall from 4 June for their major and trace element makeup, mineralogical characteristics, and 3D textural relationships within pyroclasts. The light beige, phenocryst-poor (<5 vol%) pumice contains plagioclase (~1mm) as its primary phase, and magnetite, orthopyroxene and clinopyroxene in sub-equal amounts. The crystals often form intergrowth clusters but may also be found separate and enclosed in highly vesicular microlite-free glass. As shown by XRF analyses on bulk pumice and ash samples collected from two localities southeast of the vent, the current eruptives comprise the following (in wt.%): SiO2 = 69.6, TiO2 = 0.70, Al2O3 = 14.3, Fe2O3 = 4.56, MnO = 0.11, MgO = 0.54, CaO = 2.3, Na2O = 5.14, K2O = 2.75, P2O5 = 0.11; and, (in ppm): Cr = 6.7, Ni = 2.3, Rb = 70.3, Sr = 163.3, Y = 51.7, Zr = 328, Ba = 702, Pb = 23.7. Interestingly, these compositions are virtually identical to those of magma erupted during 1960 and closely resemble rhyodacite erupted in 1921 from nearby vents. The primary difference between the present eruption and its recent predecessors is the much greater eruptive vigour of the current phase. Another distinction between the present and past historical eruptions is the presence of conspicuous mafic-felsic mingling textures in a small percentage (~0.5 vol%) of the current pumice. Textural and chemical analyses of the mafic blobs are

  19. Exploring the influence of vent location and eruption style on tephra fall hazard from the Okataina Volcanic Centre, New Zealand

    NASA Astrophysics Data System (ADS)

    Thompson, Mary Anne; Lindsay, Jan M.; Sandri, Laura; Biass, Sébastien; Bonadonna, Costanza; Jolly, Gill; Marzocchi, Warner

    2015-05-01

    Uncertainties in modelling volcanic hazards are often amplified in geographically large systems which have a diverse eruption history that comprises variable eruption styles from many different vent locations. The ~700 km2 Okataina Volcanic Centre (OVC) is a caldera complex in New Zealand which has displayed a range of eruption styles and compositions over its current phase of activity (26 ka-present), including one basaltic maar-forming eruption, one basaltic Plinian eruption and nine rhyolitic Plinian eruptions. All three of these eruption styles occurred within the past 3.5 ky, and any of these styles could occur in the event of a future eruption. The location of a future eruption is also unknown. Future vents could potentially open in one of three different areas which have been activated in the past 26 ky at the OVC: the Tarawera linear vent zone (LVZ) (five eruptions), the Haroharo LVZ (five eruptions) or outside of these LVZs (one eruption). A future rhyolitic or basaltic Plinian eruption from the OVC is likely to generate widespread tephra fall in loads that will cause significant disruption and have severe socio-economic impacts. Past OVC tephra hazard studies have focused on evaluating hazard from a rhyolitic Plinian eruption at select vent locations in the OVC's Tarawera LVZ. Here, we expand upon past studies by evaluating tephra hazard for all possible OVC eruption vent areas and for both rhyolitic and basaltic Plinian eruption styles, and explore how these parameters influence tephra hazard forecasts. Probabilistic volcanic hazard model BET_VH and advection-diffusion model TEPHRA2 were used to assess the hazard of accumulating ≥10 kg m-2 of tephra from both basaltic Plinian and rhyolitic Plinian eruption styles, occurring from within the Tarawera LVZ, the Haroharo LVZ or other potential vent areas within the caldera. Our results highlight the importance of considering all the potential vent locations of a volcanic system, in order to capture the full

  20. The eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru)

    NASA Astrophysics Data System (ADS)

    Samaniego, Pablo; Rivera, Marco; Mariño, Jersy; Guillou, Hervé; Liorzou, Céline; Zerathe, Swann; Delgado, Rosmery; Valderrama, Patricio; Scao, Vincent

    2016-09-01

    We have reconstructed the eruptive chronology of the Ampato-Sabancaya volcanic complex (Southern Peru) on the basis of extensive fieldwork, and a large dataset of geochronological (40K-40Ar, 14C and 3He) and geochemical (major and trace element) data. This volcanic complex is composed of two successive edifices that have experienced discontinuous volcanic activity from Middle Pleistocene to Holocene times. The Ampato compound volcano consists of a basal edifice constructed over at least two cone-building stages dated at 450-400 ka and 230-200 ka. After a period of quiescence, the Ampato Upper edifice was constructed firstly during an effusive stage (80-70 ka), and then by the formation of three successive peaks: the Northern, Southern (40-20 ka) and Central cones (20-10 ka). The Southern peak, which is the biggest, experienced large explosive phases, resulting in deposits such as the Corinta plinian fallout. During the Holocene, eruptive activity migrated to the NE and constructed the mostly effusive Sabancaya edifice. This cone comprised many andesitic and dacitic blocky lava flows and a young terminal cone, mostly composed of pyroclastic material. Most samples from the Ampato-Sabancaya define a broad high-K magmatic trend composed of andesites and dacites with a mineral assemblage of plagioclase, amphibole, biotite, ortho- and clino-pyroxene, and Fe-Ti oxides. A secondary trend also exists, corresponding to rare dacitic explosive eruptions (i.e. Corinta fallout and flow deposits). Both magmatic trends are derived by fractional crystallisation involving an amphibole-rich cumulate with variable amounts of upper crustal assimilation. A marked change in the overall eruptive rate has been identified between Ampato (~ 0.1 km3/ka) and Sabancaya (0.6-1.7 km3/ka). This abrupt change demonstrates that eruptive rates have not been homogeneous throughout the volcano's history. Based on tephrochronologic studies, the Late Holocene Sabancaya activity is characterised by strong

  1. Sedimentology, eruptive mechanism and facies architecture of basaltic scoria cones from the Auckland Volcanic Field (New Zealand)

    NASA Astrophysics Data System (ADS)

    Kereszturi, Gábor; Németh, Károly

    2016-09-01

    Scoria cones are a common type of basaltic to andesitic small-volume volcanoes (e.g. 10- 1-10- 5 km3) that results from gas-bubble driven explosive eruptive styles. Although they are small in volume, they can produce complex eruptions, involving multiple eruptive styles. Eight scoria cones from the Quaternary Auckland Volcanic Field in New Zealand were selected to define the eruptive style variability from their volcanic facies architecture. The reconstruction of their eruptive and pyroclastic transport mechanisms was established on the basis of study of their volcanic sedimentology, stratigraphy, and measurement of their pyroclast density, porosity, Scanning Electron Microscopy, 2D particle morphology analysis and Visible and Near Visible Infrared Spectroscopy. Collection of these data allowed defining three end-member types of scoria cones inferred to be constructed from lava-fountaining, transitional fountaining and Strombolian type, and explosive Strombolian type. Using the physical and field-based characteristics of scoriaceous samples a simple generalised facies model of basaltic scoria cones for the AVF is developed that can be extended to other scoria cones elsewhere. The typical AVF scoria cone has an initial phreatomagmatic phases that might reduce the volume of magma available for subsequent scoria cone forming eruptions. This inferred to have the main reason to have decreased cone volumes recognised from Auckland in comparison to other volcanic fields evolved dominantly in dry eruptive condition (e.g. no external water influence). It suggests that such subtle eruptive style variations through a scoria cone evolution need to be integrated into the hazard assessment of a potentially active volcanic field such as that in Auckland.

  2. 1996 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.

    1997-01-01

    During 1996, the Alaska Volcano Observatory (AVO) responded to eruptive activity, anomalous seismicity, or suspected volcanic activity at 10 of the approximately 40 active volcanic centers in the state of Alaska. As part of a formal role in KVERT (the Kamchatkan Volcano Eruption Response Team), AVO staff also disseminated information about eruptions and other volcanic unrest at six volcanic centers on the Kamchatka Peninsula and in the Kurile Islands, Russia.

  3. Psychological aspects in a volcanic crisis: El Hierro Island eruption (October, 2011).

    NASA Astrophysics Data System (ADS)

    Lopez, P.; Llinares, A.; Garcia, A.; Marrero, J. M.; Ortiz, R.

    2012-04-01

    The recent eruption on the El Hierro Island (Canary Islands, Spain) has shown that Psychology plays an important role in the emergence management of a natural phenomenon. However, Psychology continues to have no social coverage it deserves in the mitigation of the effects before, during and after the occurrence of a natural phenomenon. Keep in mind that an unresolved psychological problem involves an individual and collective mismatch may become unrecoverable. The population of El Hierro has been under a state of alert since July 2011, when seismic activity begins, until the occurrence of submarine eruption in October 2011 that is held for more than three months. During this period the inhabitants of the small island have gone through different emotional states ranging from confusion to disappointment. A volcanic eruption occurs not unexpectedly, allowing to have a time of preparation / action before the disaster. From the psychological point of view people from El Hierro Island have responded to different stages of the same natural process. Although the island of El Hierro is of volcanic origin, the population has no historical memory since the last eruption occurred in 1793. Therefore, the educational system does not adequately address the formation in volcanic risk. As a result people feel embarrassment when the seismovolcanic crisis begins, although no earthquakes felt. As an intermediate stage, when the earthquakes are felt by the population, scientists and operational Emergency Plan care to inform and prepare actions in case of a possible eruption. The population feel safe despite the concerns expressed by not knowing where, how and when the eruption will occur. Once started the submarine eruption, taking into account that all the actions (evacuation, relocation, etc.) have worked well and that both their basic needs and security are covered there are new states of mind. These new emotional states ranging from disenchantment with the phenomenology of the

  4. Fracturing of volcanic systems: Experimental insights into pre-eruptive conditions

    NASA Astrophysics Data System (ADS)

    Smith, Rosanna; Sammonds, Peter R.; Kilburn, Christopher R. J.

    2009-04-01

    Conditions for fracturing are a primary control on the behaviour of volcanic systems, especially during the approach to eruption. We here present the results of deformation experiments under simulated volcanic conditions on a porhyritic andesite from ancestral Mount Shasta. Andesite was chosen as a representative material because it is common at subduction-zone volcanoes, among both erupted products and country rock. We deformed the lava in tension and triaxial compression tests at strain rates of 10 - 5 s - 1 , confining pressures from 0 to 50 MPa and temperatures up to 900 °C. We also concurrently recorded acoustic emissions (AE), in order to monitor cracking activity. The results show that deformation behaviour changes significantly in the temperature range 600-750 °C. Thus, as temperatures increased across this interval, the tensile fracture toughness increased from 2.5 ± 0.5 MPa m 1/2 to 3.5 ± 1 MPa m 1/2, the compressive strength decreased from 110 ± 30 MPa to 55 ± 35 MPa (at 900 °C) and the corresponding Young's Modulus decreased from 20 ± 4 GPa to 6 ± 4 GPa. The changes occur when the deformation of the sample changes from elastic-brittle to brittle-ductile behaviour, which we attribute to the blunting of crack tips due to melting of the glass phase and enhanced crystal plasticity at high temperature. AE activity was observed in all experiments, indicating that earthquakes can be generated not only in country rock, but also in hot magma, such as may be found in lava domes and at the margins of magma conduits. In addition, the trends in accelerating AE event rates before sample failure were comparable to those seen in earthquakes before some volcanic eruptions and a minimum in the seismic b-value coincided with sample failure. Applied to volcanic systems, the results suggest that (1) andesite strength and elasticity will not be affected by temperature or pressure beyond ~ 10-100 m from active magma, (2) before eruptions, fractures propagate

  5. Predicting eruptions from precursory activity using remote sensing data hybridization

    NASA Astrophysics Data System (ADS)

    Reath, K. A.; Ramsey, M. S.; Dehn, J.; Webley, P. W.

    2016-07-01

    Many volcanoes produce some level of precursory activity prior to an eruption. This activity may or may not be detected depending on the available monitoring technology. In certain cases, precursors such as thermal output can be interpreted to make forecasts about the time and magnitude of the impending eruption. Kamchatka (Russia) provides an ideal natural laboratory to study a wide variety of eruption styles and precursory activity prior to an eruption. At Bezymianny volcano for example, a clear increase in thermal activity commonly occurs before an eruption, which has allowed predictions to be made months ahead of time. Conversely, the eruption of Tolbachik volcano in 2012 produced no discernable thermal precursors before the large scale effusive eruption. However, most volcanoes fall between the extremes of consistently behaved and completely undetectable, which is the case with neighboring Kliuchevskoi volcano. This study tests the effectiveness of using thermal infrared (TIR) remote sensing to track volcanic thermal precursors using data from both the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Advanced Very High Resolution Radiometer (AVHRR) sensors. It focuses on three large eruptions that produced different levels and durations of effusive and explosive behavior at Kliuchevskoi. Before each of these eruptions, TIR spaceborne sensors detected thermal anomalies (i.e., pixels with brightness temperatures > 2 °C above the background temperature). High-temporal, low-spatial resolution (i.e., ~ hours and 1 km) AVHRR data are ideal for detecting large thermal events occurring over shorter time scales, such as the hot material ejected following strombolian eruptions. In contrast, high-spatial, low-temporal resolution (i.e., days to weeks and 90 m) ASTER data enables the detection of much lower thermal activity; however, activity with a shorter duration will commonly be missed. ASTER and AVHRR data are combined to track low

  6. Phase Equilibria Impetus For Large-Volume Explosive Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Fowler, S. J.; Spera, F. J.; Bohrson, W. A.; Ghiorso, M. S.

    2006-12-01

    We have investigated the phase equilibria and associated variations in melt and magma thermodynamic and transport properties of seven large-volume silicic explosive volcanic systems through application of the MELTS (Ghiorso &Sack, 1995) algorithm. Each calculation is based on fractional crystallization along an oxygen buffer at low-pressure (0.1 - 0.3 GPa), starting from a mafic parental liquid. Site-specific geological constraints provide starting conditions for each system. We have performed calculations for seven tuffs; the Otowi (~400 km3) and Tshirege (~200 km3) members of the Bandelier Tuff, the ~600 km3 Bishop Tuff, and the 2500, 300, and 1000 km3 Yellowstone high-silica rhyolite tuffs. These represent the six largest eruptions within North America over the past ~2 million years. The seventh tuff, the 39.3 ka Campanian Ignimbrite, a 200 km3 trachytic to phonolitic ignimbrite located near Naples, Italy, is the largest explosive eruption in the Mediterranean area in the last 200 kyr. In all cases, MELTS faithfully tracks the liquid line of descent as well as the identity and composition of phenocrysts. The largest discrepancy between predicted and observed melt compositions is for CaO in all calculations. A key characteristic for each system is a pseudoinvariant temperature, Tinv, where abrupt shifts in crystallinity (1-fm, where fm is the fraction of melt), volume fraction of supercritical fluid (θ), magma compressibility, melt and magma density, and viscosity occur over a small temperature interval of order 1 - 10 K. In particular, the volume fraction of vapor increases from θ ~0.1 just below Tinv to θ >0.7 just above Tinv for each case. The rheological transition between melt-dominated (high viscosity) and bubble-dominated (low viscosity) magma occurs at θ ~0.6. We emphasize that this effect is observed under isobaric conditions and is distinct from the oft-studied phenomenon of volatile exsolution accompanying magma decompression and subsequent

  7. On the impact of different volcanic hot spot detection methods on eruption energy quantification

    NASA Astrophysics Data System (ADS)

    Pergola, Nicola; Coviello, Irina; Falconieri, Alfredo; Lacava, Teodosio; Marchese, Francesco; Tramutoli, Valerio

    2016-04-01

    Several studies have shown that sensors like the Advanced Very High Resolution Radiometer (AVHRR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) may be effectively used to identify volcanic hotspots. These sensors offer in fact some spectral channels in the Medium Infrared (MIR) and Thermal Infrared (TIR) bands together with a good compromise between spatial and temporal resolution suited to study and monitor thermal volcanic activity. Many algorithms were developed to identify volcanic thermal anomalies from space with some of them that were extensively tested in very different geographich areas. In this work, we analyze the volcanic radiative power (VRP) representing one of parameters of major interest for volcanologists that may be estimated by satellite. In particular, we compare the radiative power estimations driven by some well-established state of the art hotspot detection methods (e.g. RSTVOLC, MODVOLC, HOTSAT). Differences in terms of radiative power estimations achieved during recent Mt. Etna (Italy) eruptions will be evaluated, assessing how much the VRP retrieved during effusive eruptions is affected by the sensitivity of hotspot detection methods.

  8. 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

  9. Spatio-temporal occurrence of eruptions in El Hierro (Canary Islands). Sequential steps for long-term volcanic hazard assessment.

    NASA Astrophysics Data System (ADS)

    Becerril, Laura; Bartolini, Stefania; Sobradelo, Rosa; Martí, Joan; María Morales, José; Galindo, Inés; Geyer, Adelina

    2014-05-01

    Long term volcanic hazard assessment requires the attainment of several sequential steps, including the compilation of geological and volcanological information, the characterization of past eruptions, spatial and temporal probabilistic studies, and the simulation of different eruptive scenarios to get qualitative and representative results. Volcanic hazard assessment has not been yet systematically conducted in the Canary Islands, in spite of being a densely populated active volcanic region that receives millions of visitors per year. In this paper we focus our attention on El Hierro, the youngest and latest island affected by an eruption in the Canary Islands. We analyze the past eruptive activity (how), the spatial probability (where), and the temporal probability (when) on the island. Looking at the past eruptive behavior of the island, and assuming future eruptive patterns will be similar, we try to identify the most likely set of volcanic scenarios and corresponding hazards that could occur in the future (eg. lava flows, pyroclastic fallout, and pyroclastic density currents) and estimate their probability of occurrence. The final result shows the first volcanic hazard map of the island. This study represents a step forward in the evaluation of long term volcanic hazard at El Hierro Island with regard to previous studies. The obtained results should represent the main pillars on which to build risk mitigation programs as it is required for territorial planning and to develop emergency plans. This research was partially funded by IGME, CSIC and the European Commission (FT7 Theme: ENV.2011.1.3.3-1; Grant 282759: "VUELCO"), and MINECO grant GL2011-16144-E.

  10. Volcanic eruptions and seismicity of Mt. Baekdu (Changbai) occurred in the historical time

    NASA Astrophysics Data System (ADS)

    Kang, T.; Baag, C.; Chu, K.

    2011-12-01

    Recently, it was reported that the Mt. Baekdu had large volcanic eruptions at least two times in the geological and historical times and the lake Cheonji (Tianchi in Chinese) had formed by collapse of the summit part of the mountain. The last one of the four eruptions occurred in the historical time. Geologists tried to measure the date of eruptions using carbon isotope, but the results show diversity ranging approximately form AD 8 to 14 centuries corresponding to the dates of two dynasties of Balhae (Bohai in Chinese) and Goryeo. Unfortunately, there is no distinct record of the eruptions in this period in historical literatures. In the current study, we could infer that the last great volcanic eruption occurred in the winter time with strong northwestern seasonal wind, considering the distribution of pumice on the satellite images and the thickness of the pumice layers measured at sites in relationship with the climatic environment. On the other hand, some researchers interpreted five events appearing in historical documents written in the Joseon dynasty to be related to volcanic eruptions of Mt. Baekdu. These events occurred in the years 1413, 1597, 1668, 1702, and 1903. Their interpretations have been widely cited in journals and books, However based on critical reviews of historical literature including Joseon Wangjo Sillok (Annals of the Joseon Dynasty), we find that three events of the five were not related to volcanic eruptions of the Mt. Baekdu. Events in the years 1413 and 1668 were phenomena of Asian dust. The event in 1903 recorded in a Chinese literature is found to be a shower type of rain drop with hail accompanied by thunder and lightning. Only the two events in 1597 and 1702 are confirmed to be related to volcanic activities of Mt. Baekdu. According to Joseon Wangjo Sillok, a large earthquake of maximum intensity 9 (Modified Mercalli Intensity, MMI) and its aftershocks occurred at the border region of Samsu county in Hamgyeongdo Province in the

  11. Degassing mechanism change regarding an eruption in 2009 at Mt. Asama revealed by volcanic gas and seismic studies

    NASA Astrophysics Data System (ADS)

    Kazahaya, R.; Shinohara, H.; Kazahaya, K.; Ohwada, M.; Mori, T.; Takeo, M.; Ohminato, T.; Ichihara, M.; Aoki, Y.; Maeda, Y.; Miyashita, M.

    2012-12-01

    Volcanic gas has a close relationship with geophysical phenomena involving eruptive activities. In particular, previous studies suggested that very-long-period (VLP) seismic signals are caused by fluid (i.e., gas and/or magma) within a volcano (e.g., Chouet et al. 2010). Investigation for VLP seismic source is crucial not only for volcanic seismology but also for understanding degassing processes at depths. In this study, at Mt. Asama, Japan, we examine VLP seismic source model of the volcano and change of degassing mechanism before and after an eruption in Feb. 2009 by means of a linkage between volcanic sulfur dioxide emission and VLP seismic moment, which was revealed by Kazahaya et al. (2011). This linear relationship between them implies that volcanic gas injected into the VLP seismic source causes a VLP pulse. Complementing it with volcanic gas composition data, we calculated pressure/volumetric changes at the VLP seismic source both by volcanic gas amount and by seismic analyses; and found a significant difference between them. We propose the VLP seismic source filled with pressure (porous) medium so as to explain this discrepancy. This linear relation between volcanic gas and VLP seismic signal allows us to calculate gas amount triggering VLP pulses from seismic record. The long-term time series of volcanic gas emission which gives rise to VLP pulses were examined; the ratio of gas emission regarding VLP pulses showed drastic change before and after the eruption in Feb. 2009. The novel timeline data suggest that degassing mechanism at the depth within the volcano changed by the eruption to excite VLP seismicity easier. GPS and infrasonic data may give constraints to comprehend the volcanic structure such as magma supply and gas exhalation, respectively. Collaboration of geochemical and geophysical studies opens up the possibility to get brand new insights within the volcano.

  12. Evaluation of climate impacts after a large volcanic eruption during stratospheric sulfur injections

    NASA Astrophysics Data System (ADS)

    Laakso, Anton; Kokkola, Harri; Partanen, Antti-Ilari; Niemeier, Ulrike; Timmreck, Claudia; Lehtinen, Kari; Hakkarainen, Hanne; Korhonen, Hannele

    2016-04-01

    Solar radiation management (SRM) by injecting sulfur to the stratosphere is one of the most discussed geoengineering methods, because it has been suggested to be affordable and effective and its impacts have been thought to be predictable based on volcanic eruptions. Injecting sulfur to the stratosphere could be seen as an analogy of large volcanic eruptions, where large amounts of sulfur dioxide are released into the stratosphere. In the atmosphere sulfur dioxide oxidizes and forms aqueous sulfuric acid aerosols which reflect incoming solar radiation back to space. If SRM is ever used to cool the climate it is possible that a large volcanic eruption could happen also during the SRM, which would lead temporally to a very strong cooling. The simulations in this study were performed in two steps. In the first step, we used the aerosol-climate model MAECHAM5-HAM-SALSA to define global aerosol fields in scenarios with stratospheric sulfur injections and/or a volcanic eruption. In the second step of the study we performed climate simulations using Max-Planck-Institute's Earth system model (MPI-ESM) by using aerosol fields defined by MAECHAM5-HAM-SALSA. We studied scenarios of volcanic eruptions in two different locations and seasons and during the SRM sulfur injections and without injections. According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. Adding to this, sulfate burden and radiative forcing after the volcanic eruption decrease significantly faster if the volcanic eruption happens during the geoengineering injections. In this situation, sulfur from the eruption does not only form new particles but it also condenses into pre-existing particles. Furthermore, the new small particles that are formed after the eruption coagulate effectively with the existing larger particles from

  13. Solar Activity and Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Sterling, Alphonse C.

    2006-01-01

    Our Sun is a dynamic, ever-changing star. In general, its atmosphere displays major variation on an 11-year cycle. Throughout the cycle, the atmosphere occasionally exhibits large, sudden outbursts of energy. These "solar eruptions" manifest themselves in the form of solar flares, filament eruptions, coronal mass ejections (CMEs), and energetic particle releases. They are of high interest to scientists both because they represent fundamental processes that occur in various astrophysical context, and because, if directed toward Earth, they can disrupt Earth-based systems and satellites. Research over the last few decades has shown that the source of the eruptions is localized regions of energy-storing magnetic field on the Sun that become destabilized, leading to a release of the stored energy. Solar scientists have (probably) unraveled the basic outline of what happens in these eruptions, but many details are still not understood. In recent years we have been studying what triggers these magnetic eruptions, using ground-based and satellite-based solar observations in combination with predictions from various theoretical models. We will present an overview of solar activity and solar eruptions, give results from some of our own research, and discuss questions that remain to be explored.

  14. Recent Eruptive History of the Tatun Volcanic Group, Northern Taiwan: Hazard-related Issues

    NASA Astrophysics Data System (ADS)

    Belousov, A.; Belousova, M.; Chen, C.

    2009-12-01

    The Quaternary dominantly andesitic Tatun Volcanic Group (TVG) occupies 400 km2 in the northern part of Taiwan Island. The group has more than 20 well-preserved volcanic edifices, multiple hot springs and fumaroles as hot as 120oC with magmatic isotopic signatures. Local seismic network has registered shallow volcano-tectonic earthquakes in the area. The TVG is surrounded by densely populated areas, the largest of which is Taipei City (7 million people), as well as by multiple industrial factories and two nuclear power plants. Therefore, the question about timing and styles of the most recent TVG eruptions is important. We report results of our investigations of TVG physical volcanology, with focus on pyroclastic stratigraphy and eruption dynamics. For the most recent TVG eruptions were common long-term extrusions of crystal-rich, viscous lava. The eruptions formed dominantly monogenetic plug domes, coulees, and lava flows. The domes have heights of 150-350 m, base diameters of 0.5-1.0 km, and volumes of 0.05-0.3 km3. The nine best-preserved TVG lava flows have thicknesses of 80-150 m, lengths of 1-7.5 km, and volumes of 0.07-0.6 km3. For the largest lava flow we estimated an effusion rate of 6.4 m3/s, eruption duration of 1100 days, lava front speed of 2-3 m/hour (method, e.g. Stevenson et al. 1994). The only pyroclastic edifice of the Tatun group is a tephra ring ~ 500 m in diameter and 40 m high formed by plinian eruption. Apart from that, few non-reworked pyroclastic deposits are currently preserved at TVG. The available data have shown that the explosive activity of TVG was weak-to-mild, but rather diverse with deposition of fallout tephra, base surges, and pyroclastic flows. Fallout deposits are represented mostly by well-sorted, crystal-rich ash layers (Md=1.0-3.4 phi, sorting = 0.9-2.4 phi) left by Vulcanian-type activity. Deposits of pumice fallout (Md = -4-(-2.5) phi, sorting = 1.2-2.4 phi) from Plinian eruptions are less common. Many of the eruptions

  15. Young volcanoes in the Chilean Southern Volcanic Zone: A statistical approach to eruption prediction based on time series

    NASA Astrophysics Data System (ADS)

    Dzierma, Y.; Wehrmann, H.

    2010-03-01

    Forecasting volcanic activity has long been an aim of applied volcanology with regard to mitigating consequences of volcanic eruptions. Effective disaster management requires both information on expected physical eruption behaviour such as types and magnitudes of eruptions as typical for the individual volcano, usually reconstructed from deposits of past eruptions, and the likelihood that a new eruption will occur within a given time. Here we apply a statistical procedure to provide a probability estimate for future eruptions based on eruption time series, and discuss the limitations of this approach. The statistical investigation encompasses a series of young volcanoes of the Chilean Southern Volcanic Zone. Most of the volcanoes considered have been active in historical times, in addition to several volcanoes with a longer eruption record from Late-Pleistocene to Holocene. Furthermore, eruption rates of neighbouring volcanoes are compared with the aim to reveal possible regional relations, potentially resulting from local to medium-scale tectonic dynamics. One special focus is directed to the two currently most active volcanoes of South America, Llaima and Villarrica, whose eruption records comprise about 50 historical eruptions over the past centuries. These two front volcanoes are considered together with Lanín Volcano, situated in the back-arc of Villarrica, for which the analysis is based on eight eruptions in the past 10 ka. For Llaima and Villarrica, affirmed tests for independence of the repose times between successive eruptions permit to assume Poisson processes; which is hampered for Lanín because of the more limited availability of documented eruptions. The assumption of stationarity reaches varying degrees of confidence depending on the time interval considered, ameliorating towards the more recent and hence probably more complete eruption record. With these pre-requisites of the time series, several distribution functions are fit and the goodness of

  16. Biogeochemical impacts of volcanic eruptions on alkaline lake environments: A case study on Lake Van in the eastern Turkey

    NASA Astrophysics Data System (ADS)

    Olgun, Nazli; Çagatay, Namık; Aksu, Abdullah; Balkıs, Nuray; Kaiser, Jerome; Öveçoglu, Lütfi; Özcan, Mustafa

    2014-05-01

    Volcanic ashes ejected during explosive volcanic eruptions can release more than fifty-five soluble elements in contact with water, most of which have environmental significance such as fluoride, chloride, the nutrients like the fixed-nitrogen, phosphate, silica and a variety of key trace metals including iron. Deposition of volcanic ash onto the aqueous environments can therefore affect the water geochemistry and eventually the phytoplankton growth in the ash fallout regions. Alkaline (soda) lakes are distributed world-wide and located almost exclusively in the volcanic regions, which have been related to the long term dissolution of volcanic products. However, although alkali lakes are found in the high volcanic impact regions, the way in which the biogeochemistry of the alkaline lake waters is affected by the volcanic eruptions still remains unknown. Lake Van, located in the eastern Turkey, is the largest of the alkaline lakes on Earth and had been exposed to various volcanic ash fallouts produced by the historical eruptions of neighbouring semi-active volcanoes Nemrut, Süphan and Tendürek. Here, we present new data from geochemical analyses of Lake Van sediments, aiming to determine the potential changes in the primary productivity related to the volcanic eruptions, by using organic biomarkers such as pigments chlorin and fucoxanthin, long chain alkenons, total organic and inorganic carbon contents of sediment layers above and below the ten selected tephra fallout deposits dating back from 1 ka to 82 ka. Furthermore, we have performed microscopic observations of the microfossils (diatoms and coccoliths) in the Lake Van sediments. Our data pointed out variable changes related to different fallout deposits including significant positive (fertilizing affect) and negative (toxic affect) impacts and as well as nearly negligible changes in the biomarker concentrations in the sediments overlying the ten tephra layers compared to the underlying sediments. We suggest

  17. Effect of recent minor volcanic eruptions on temperatures in the upper troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Mehta, Sanjay Kumar; Fujiwara, Masatomo; Tsuda, Toshitaka; Vernier, Jean-Paul

    2015-07-01

    The impact of the recent minor volcanic eruptions during 2001-2010 in the temperature of the upper troposphere and lower stratosphere (UTLS) is investigated using data from the Global Positioning System Radio Occultation (GPS RO), three radiosonde compilations and two reanalyses (ERA-Interim and MERRA). The volcanic signals are identified in the residual temperature time series after removal of the linear trend, the quasi-biennial oscillation and El Nino Southern Oscillation components. Eight minor volcanic eruptions (six from the tropics and two from midlatitude) over the last decade (2001-2010) are analyzed in this study. We found significant volcanic signals in the UTLS temperature only in association with the tropical Soufrière Hills and Tavurvur eruptions (in May 2006 and in October 2006, respectively). Other four tropical eruptions had very small aerosol perturbations and did not show any significant UTLS temperature change. Out of the two midlatitude eruptions, Sarychev peak had similar stratospheric aerosol perturbations as Soufrière Hills and Tavurvur eruptions, but did not show any significant UTLS temperature change. The volcanic signals in the UTLS temperature from the tropical Soufrière Hills and Tavurvur eruptions were observed for the period of 7 months after August 2006. A warming of 0.5-0.8 K in the tropical 16-18.5 km (100-70 hPa) layer was observed in association with these two tropical eruptions.

  18. Spatial probability distribution of future volcanic eruptions at El Hierro Island (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Becerril, Laura; Cappello, Annalisa; Galindo, Inés; Neri, Marco; Del Negro, Ciro

    2013-05-01

    The 2011 submarine eruption that took place in the proximity of El Hierro Island (Canary Islands, Spain) has raised the need to identify the most likely future emission zones even on volcanoes characterized by low frequency activity. Here, we propose a probabilistic method to build the susceptibility map of El Hierro, i.e. the spatial distribution of vent opening for future eruptions, based on the probabilistic analysis of volcano-structural data of the Island collected through new fieldwork measurements, bathymetric information, as well as analysis of geological maps, orthophotos and aerial photographs. These data have been divided into different datasets and converted into separate and weighted probability density functions, which were included in a non-homogeneous Poisson process to produce the volcanic susceptibility map. The most likely area to host new eruptions in El Hierro is in the south-western part of the West rift. High probability locations are also found in the Northeast and South rifts, and along the submarine parts of the rifts. This map represents the first effort to deal with the volcanic hazard at El Hierro and can be a support tool for decision makers in land planning, emergency measures and civil defense actions.

  19. Atmospheric Dispersal and Dispostion of Tephra From a Potential Volcanic Eruption at Yucca Mountain, Nevada

    SciTech Connect

    G. Keating; W.Statham

    2004-02-12

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (ASHPLUME) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. The ASHPLUME conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The ASHPLUME mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report will improve and clarify the previous documentation of the ASHPLUME mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model.

  20. The Tolbachik volcanic massif: A review of the petrology, volcanology and eruption history prior to the 2012-2013 eruption

    NASA Astrophysics Data System (ADS)

    Churikova, T. G.; Gordeychik, B. N.; Edwards, B. R.; Ponomareva, V. V.; Zelenin, E. A.

    2015-12-01

    The primary goal of this paper is to summarize all of the published data on the Tolbachik volcanic massif in order to provide a clear framework for the geochronologic, petrologic, geochemical and to a lesser extent the geophysical and tectonic characteristics of the Tolbachik system established prior to the 2012-2013 eruption. The Tolbachik massif forms the southwestern part of the voluminous Klyuchevskoy volcanic group in Kamchatka. The massif includes two large stratovolcanoes, Ostry ("Sharp") Tolbachik and Plosky ("Flat") Tolbachik, and a 70 km long zone of the basaltic monogenetic cones that form an arcuate rift-like structure running across the Plosky Tolbachik summit. The Tolbachik massif gained international attention after the 1975-1976 Great Tolbachik Fissure Eruption (GTFE), which was one of the largest eruptions of the 20th century and one of the six largest basaltic fissure eruptions in historical time. By the end of the GTFE, 2.2 km3 of volcanic products of variable basaltic compositions with MORB-like isotopic characteristics covered an area of > 1000 km2. During the following three decades more than 700 papers on various aspects of this eruption have been published both in national and international journals. Although the recent 2012-2013 eruption, which is the main topic of this volume, was not as long as the GTFE in duration or as large in area and volume of the erupted deposits, it brought to the surface a unique volcanic material never found before. In order to understand the data from new eruptions and make significant progress towards a better understanding of the Tolbachik magmatic system it is important to be able to put the new results into the historic context of previous research.

  1. 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

  2. Forecasting volcanic eruptions: the control of elastic-brittle deformation

    NASA Astrophysics Data System (ADS)

    Kilburn, Christopher; Robertson, Robert; Wall, Richard; Steele, Alexander

    2016-04-01

    At volcanoes reawakening after long repose, patterns of unrest normally reflect the elastic-brittle deformation of crust above a magma reservoir. Local fault movements, detected as volcano-tectonic (VT) earthquakes, increase in number with surface deformation, at first approximately exponentially and then linearly. The trends describe how crustal behaviour evolves from quasi-elastic deformation under an increasing stress to inelastic deformation under a constant stress. They have been quantified and verified against experiments for deformation in compression [1]. We have extended the analysis to extensional deformation. The results agree well with field data for crust being stretched by a pressurizing magmatic system [2]. They also provide new criteria for enhancing the definitions of alert levels and preferred times to eruption. The VT-deformation sequence is a field proxy for changes in deformation with applied stress. The transition from quasi-elastic to inelastic behaviour is characterised in extension by the ratio of differential failure stress SF to tensile strength σT. Unrest data from at least basaltic to andesitic stratovolcanoes, as well as large calderas, yield preferred values for SF/σT ≤ 4, coinciding with the range for tensile failure expected from established theoretical constraints (from Mohr-Coulomb-Griffiths failure). We thus associate the transition with the approach to tensile rupture at the wall of a pressurized magma reservoir. In particular, values of about 2 are consistent with the rupture of a cylindrical reservoir, such as a closed conduit within a volcanic edifice, whereas values of about 3 suggest an approximately spherical reservoir, such as may exist at deeper levels. The onset of inelastic behaviour reflects the emergence of self-accelerating crack growth under a constant stress. Applied to forecasting eruptions, it provides a new and objective criterion for raising alert levels during an emergency; it yields the classic linear

  3. Eruptive history and geochronology of the Mount Baker volcanic field, Washington

    USGS Publications Warehouse

    Hildreth, W.; Fierstein, J.; Lanphere, M.

    2003-01-01

    Mount Baker, a steaming, ice-mantled, andesitic stratovolcano, is the most conspicuous component of a multivent Quaternary volcanic field active almost continuously since 1.3 Ma. More than 70 packages of lava flows and ???110 dikes have been mapped, ???500 samples chemically analyzed, and ???80 K-Ar and 40Ar/39Ar ages determined. Principal components are (1) the ignimbrite-filled Kulshan caldera (1.15 Ma) and its precaldera and postcaldera rhyodacite lavas and dikes (1.29-0.99 Ma); (2) ???60 intracaldera, hydrothermally altered, andesite-dacite dikes and pods-remnants of a substantial early-postcaldera volcanic center (1.1-0.6 Ma); (3) unaltered intracaldera andesite lavas and dikes, including those capping Ptarmigan and Lasiocarpa Ridges and Table Mountain (0.5-0.2 Ma); (4) the long-lived Chowder Ridge focus (1.29-0.1 Ma)-an andesite to rhyodacite eruptive complex now glacially reduced to ???50 dikes and remnants of ???10 lava flows; (5) Black Buttes stratocone, basaltic to dacitic, and several contemporaneous peripheral volcanoes (0.5-0.2 Ma); and (6) Mount Baker stratocone and contemporaneous peripheral volcanoes (0.1 Ma to Holocene). Glacial ice has influenced eruptions and amplified erosion throughout the lifetime of the volcanic field. Although more than half the material erupted has been eroded, liberal and conservative volume estimates for 77 increments of known age yield cumulative curves of volume erupted vs. time that indicate eruption rates in the range 0.17-0.43 km3/k.y. for major episodes and longterm background rates of 0.02-0.07 km3/k.y. Andesite and rhyodacite each make up nearly half of the 161 ?? 56 km3 of products erupted, whereas basalt and dacite represent only a few cubic kilometers, each representing 1%-3% the total. During the past 4 m.y., the principal magmatic focus has migrated stepwise 25 km southwestward, from the edge of the Chilliwack batholith to present-day Mount Baker.

  4. Gas and hydrogen isotopic analyses of volcanic eruption clouds in Guatemala sampled by aircraft

    USGS Publications Warehouse

    Rose, W.I.; Cadle, R.D.; Heidt, L.E.; Friedman, I.; Lazrus, A.L.; Huebert, B.J.

    1980-01-01

    Gas samples were collected by aircraft entering volcanic eruption clouds of three Guatemalan volcanoes. Gas chromatographic analyses show higher H2 and S gas contents in ash eruption clouds and lower H2 and S gases in vaporous gas plumes. H isotopic data demonstrate lighter isotopic distribution of water vapor in ash eruption clouds than in vaporous gas plumes. Most of the H2O in the vaporous plumes is probably meteoric. The data are the first direct gas analyses of explosive eruptive clouds, and demonstrate that, in spite of atmospheric admixture, useful compositional information on eruptive gases can be obtained using aircraft. ?? 1980.

  5. Trace element degassing patterns and volcanic fluxes to the atmosphere during the 2014 Holuhraun eruption, Iceland

    NASA Astrophysics Data System (ADS)

    Gauthier, Pierre-Jean; Sigmarsson, Olgeir; Moune, Séverine; Haddadi, Baptiste; Gouhier, Mathieu

    2015-04-01

    Trace elements are well known to be volatile at magma temperature and enriched in volcanic gases from active volcanoes worldwide. However, little is known so far regarding their volatility at Icelandic volcanoes, mostly because high temperature volcanic gases are often inaccessible. The 2014 Holuhraun eruption that began on August 29 is characterized by both high extrusion rates of lava and intensive degassing which gives rise to a volcanic plume made of volcanic gases, aerosols and fine solid particles. A unique opportunity to sample the diluted plume at the eruption site was given to us on October 2. Volcanic aerosols were collected on washed PTFE membranes by pumping through the diluted plume for 30 minutes to 1 hour. Reactive gases were simultaneously trapped on impregnated filters, yielding a SO2/HCl molar ratio at the eruption site of 29-46 and SO2 concentrations in the diluted plume up to 200 mg/m3 (Haddadi et al., EGU 2015). PTFE filters were leached in 5 ml of a diluted HNO3-HF mixture for one week at 90°C. Solutions were subsequently analyzed by ICP-MS using a synthetic reference solution at 10 ppb for external calibration. Both siderophile (Mo, W, Re) and calchophile trace metals (Cu, Zn, As, Se, Cd, In, Sn, Sb, Te, Tl, Pb, Bi) were found to be significantly enriched in the diluted volcanic plume of Holuhraun compared to the background atmosphere in Iceland. Measured concentrations range from less than 0.1 ng/m3 for W up to 400 ng/m3 of Cd. Enrichment factors (EF) relative to Mg, considered as a strictly lithophile element with extremely low volatility, were computed for all analyzed trace metals. The least volatile elements (W, Cu, Zn, Mo, Ag) have EFs in the range 50-300 while the most volatile elements (Cd, Bi, Re, Se, Te) have EFs as high as 10E6. The overall degassing pattern observed at Holuhraun is consistent with those previously reported for other mantle plume related volcanoes like Kilauea (Mather et al., Geochim. Cosmochim. Acta, 2012) and

  6. On numerical simulation of the global distribution of sulfate aerosol produced by a large volcanic eruption

    SciTech Connect

    Pudykiewicz, J.A.; Dastoor, A.P.

    1994-12-31

    Volcanic eruptions play an important role in the global sulfur cycle of the Earth`s atmosphere and can significantly perturb the global atmospheric chemistry. The large amount of sulfate aerosol produced by the oxidation of SO{sub 2} injected into the atmosphere during volcanic eruptions also has a relatively big influence on the radiative equilibrium of the Earth`s climatic system. The submicron particles of the sulfate aerosol reflect solar radiation more effectively than they trap radiation in the infrared range. The effect of this is observed as cooling of the Earth`s surface. The modification of the global radiation budget following volcanic eruption can subsequently cause significant fluctuations of atmospheric variables on a subclimatic scale. The resulting perturbation of weather patterns has been observed and well documented since the eruptions of Mt. Krakatau and Mt. Tambora. The impact of the sulfate aerosol from volcanic eruptions on the radiative equilibrium of the Earth`s atmosphere was also confirmed by the studies done with Global Circulation Models designed to simulate climate. The objective of the present paper is to present a simple and effective method to estimate the global distribution of the sulfate aerosol produced as a consequence of volcanic eruptions. In this study we will present results of the simulation of global distribution of sulfate aerosol from the eruption of Mt Pinatubo.

  7. The response of winter Pacific North American pattern to strong volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Liu, Zhongfang; Yoshimura, Kei; Buenning, Nikolaus H.; Jian, Zhimin; Zhao, Liang

    2016-07-01

    The impact of volcanic eruptions on large-scale atmospheric circulation patterns has been well studied, but very little effort has been made on relating the response of Pacific North American (PNA) pattern to strong volcanic eruptions. Here we investigate the response of winter PNA to the largest volcanic eruptions using three different reanalysis datasets. We demonstrate a significant positive PNA circulation response to strong volcanic forcing in the first winter following the eruptions. This circulation pattern is associated with enhanced southwesterly winds advecting warm air from the tropical/subtropical Pacific into northwestern North America and leads to a significant warming in the region. However, no significant PNA signal is found for the second post-eruption winter. The PNA responses to volcanic forcing depend partly upon the modulation of the El Niño Southern Oscillation (ENSO) events. When the ENSO influence is linearly removed, this positive PNA signal is still robust during the first post-eruption winter, albeit with slightly decreased magnitude and significance. Our findings provide new evidence for volcanic forcing of the Pacific and North American climates. The results presented here may contribute to deconvolving modern and past continental-scale climate changes over North America.

  8. Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

    NASA Astrophysics Data System (ADS)

    Laakso, A.; Kokkola, H.; Partanen, A.-I.; Niemeier, U.; Timmreck, C.; Lehtinen, K. E. J.; Hakkarainen, H.; Korhonen, H.

    2015-08-01

    Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere. In addition, the recovery of the stratospheric sulfate burden and forcing was significantly faster in the concurrent case since the sulfate particles grew larger and thus sedimented faster from the stratosphere. In our simulation where we assumed that SRM would be stopped immediately after a volcano eruption, stopping SRM decreased the overall stratospheric aerosol load. For the same reasons, a volcanic eruption during SRM lead to only about 1/3 of the peak global ensemble-mean cooling compared to an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal was seen only for 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of the global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mt Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption

  9. 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

  10. 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

  11. Violent Explosive Eruptions in the Ararat Valley, Armenia and Associated Volcanic Hazards

    NASA Astrophysics Data System (ADS)

    Meliksetian, Khachatur; Savov, Ivan; Connor, Charles; Gevorgyan, Hripsime; Connor, Laura; Navasardyan, Gevorg; Manucharyan, Davit; Jrbashyan, Ruben; Ghukasyan, Yura

    2016-04-01

    The Anatolian-Armenian-Iranian volcanically active orogenic plateau is located in the collision zone between the Arabian and Eurasian plates. The majority of regional geodynamic and petrologic models of collision-related magmatism use the model proposed by Keskin (2003), where volcanism is driven by Neo-Tethyan slab break-off, however an updated model by Neill et al. (2015) and Skolbeltsyn et al.(2014) comprise break-off of two slabs. One of the significant (and understudied) features of the regionally extensive collision zone volcanism is the diversity of eruption styles and also the presence of large number of highly explosive (Plinian) eruptions with VEI≥5 during the Middle-Upper Pleistocene. Geological records of the Ararat depression include several generations of thick low aspect ratio Quaternary ignimbrites erupted from Aragats volcano, as well as up to 3 m thick ash and pumice fall deposit from the Holocene-historically active Ararat volcano. The Ararat tephra fall deposit is studied at 12 newly discovered outcrops covering an area ˜1000 km2. It is noteworthy, that the Ararat tephra deposits are loose and unwelded and observed only in cross-sections in small depressions or in areas where they were rapidly covered by younger, colluvium deposits, presumably of Holocene age. Therefore, the spatial extent of the explosive deposits of Ararat is much bigger but not well preserved due to rapid erosion. Whole rock elemental, isotope (Sr, Nd) and mineral chemistry data demonstrate significant difference in the magma sources of the large Aragats and Ararat stratovolcanoes. Lavas and pyroclastic products of Aragats are high K calc-alkaline, and nearly always deprived from H2O rich phases such as amphibole. In contrasts lavas and pyroclastic products from Ararat are medium K calc-alkaline and volatile-rich (>4.6 wt% H2O and amphibole bearing) magmas. Here we shall attempt to reveal possible geochemical triggers of explosive eruptions in these volcanoes and assess

  12. Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering

    NASA Astrophysics Data System (ADS)

    Laakso, A.; Kokkola, H.; Partanen, A.-I.; Niemeier, U.; Timmreck, C.; Lehtinen, K. E. J.; Hakkarainen, H.; Korhonen, H.

    2016-01-01

    Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an Earth system model to study the radiative and climate changes occurring after an erupting volcano during solar radiation management (SRM). According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. In the former case, the peak burden of the additional stratospheric sulfate as well as changes in global mean precipitation are fairly similar regardless of whether the eruption takes place in a SRM or non-SRM world. However, the maximum increase in the global mean radiative forcing caused by the eruption is approximately 21 % lower compared to a case when the eruption occurs in an unperturbed atmosphere. In addition, the recovery of the stratospheric sulfur burden and radiative forcing is significantly faster after the eruption, because the eruption during the SRM leads to a smaller number and larger sulfate particles compared to the eruption in a non-SRM world. On the other hand, if SRM is suspended immediately after the eruption, the peak increase in global forcing caused by the eruption is about 32 % lower compared to a corresponding eruption into a clean background atmosphere. In this simulation, only about one-third of the global ensemble-mean cooling occurs after the eruption, compared to that occurring after an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal is seen only for the 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of global precipitation rate, we obtain a 36 % smaller decrease in the

  13. Explosive volcanic eruptions, the El Nino-southern oscillation, and U.S. climate variability

    SciTech Connect

    Portman, D.A.

    1996-01-01

    A study was conducted to identify and separate possible signals of volcanic eruptions and of the El Nino Southern Oscillation (ENSO) in U.S. surface climate records. Anomalies of monthly mean surface air temperature and total precipitation taken from the U.S. Historical Climatology Network were composited (averaged) over years of major explosive volcanic eruptions, ENSO warm events, and ENSO cold events since the year 1900. It was assumed that volcanic eruptions and ENSO events occur independently of each other. All composite anomalies were assessed for significance with regard to several statistical and physical criteria. The composite ENSO-related anomalies were then subtracted from anomalies of temperature and precipitation associated with the volcanic eruptions. Removal of large magnitude and highly significant anomalies associated with the ENSO warm and cold events is found to facilitate detection of volcanic signals in monthly records of U.S. temperature and precipitation. Volcanic signals are strongly suggested east of the Continental Divide, for example, where positive monthly temperature anomalies exceeding 1{degrees}C occur during the first fall and winter after eruptions. Negative temperature anomalies occur west of the Continental Divide during the first winter and spring after eruptions and in the southern United States during the summer of the first post-eruption calendar year. Positive monthly precipitation anomalies exceeding 15 mm in magnitude are found in the southeastern United States during the first winter and spring after eruptions. Precipitation anomalies that are smaller in magnitude and yet significant, such as positive anomalies in the northwestern United States and negative anomalies in the central and eastern United States, are found during the summer of the first post-eruption calendar year. 62 refs., 9 figs., 4 tabs.

  14. 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

  15. Amazonian volcanic activity at the Syrtis volcanic province, Mars

    NASA Astrophysics Data System (ADS)

    Platz, Thomas; Jodlowski, Piotr; Fawdon, Peter; Michael, Greg; Tanaka, Kenneth

    2014-05-01

    The Syrtis Major volcanic province, including the entire Syrtis Major Planum, is located near the Martian highland/lowland transitional zone west of Isidis Planitia. It covers ≡7.4×105 km2 and contains two low-shield volcanic edifices with N-S elongated calderas named Nili and Meroe Paterae. The estimated thickness of erupted material in the province ranges from approximately 0.5 km to 1.0 km with a total volume of about 1.6-3.2×105 km3 [1]. The timing of volcanic activity in the Syrtis Major volcanic province has been suggested to be restricted to the Hesperian Period [1-4]. In the geological map of Greeley and Guest [2], volcanic material of Syrtis Major was assigned an Hesperian age based on the density of observed craters larger than 5 km in diameter. Using the same crater density range, recent studies of Hiesinger et al. [1] and Tanaka et al. [3] and Tanaka et al. [4] assigned an Early Hesperian and Early to Late Hesperian age, respectively, for the entire province. In this study we mapped lava flows, lava channels, and major lava-flow margins and report model ages for lava-flow formation and caldera segments of Nili and Meroe Paterae. The objective of this ongoing survey is to better understand the eruption frequency of this volcanic province. In total, we mapped 67 lava flows, caldera segments, and intra-crater fillings of which 55 were dated. Crater size-frequency distributions (CSFD) were mapped on HRSC and CTX imagery using CraterTools [5]. CSFDs were analyzed and model ages determined in Craterstats [6] using the production and chronology functions of Ivanov [7] and Hartmann and Neukum [8], respectively. A detailed description of the utilization of the crater-counting technique and its limitations with respect to small-scale mapping is given in Platz et al. [9]. Model ages range between 838 Ma (Middle Amazonian) to 3.6 Ga (Late Hesperian). In our survey, a broad age peak occurs between 2 to 2.6 Ga, continuously declining thereafter. We note that

  16. The mechanism of polar vortex strengthening after large tropical volcanic eruptions as simulated in the MPI-ESM

    NASA Astrophysics Data System (ADS)

    Bittner, Matthias; Timmreck, Claudia; Schmidt, Hauke; Toohey, Matthew; Krueger, Kirstin

    2016-04-01

    State-of-the-art climate models that have participated in the recent CMIP5 model intercomparison activity do, on average, not produce the strengthened northern hemispheric (NH) polar vortex after historical large tropical volcanic eruptions as suggested by observations. Here, we study the impact of volcanic eruptions of different strength on the NH winter stratosphere in the MPI-ESM Earth system model. We compare the dynamical impact in ensemble simulations of a very large Tambora eruption in 1815 with the response to the two largest eruptions of the CMIP5 historical simulations (Krakatau, 1883; and Mt. Pinatubo, 1991). The mechanism, of the strengthening of the vortex can clearly be identified in the simulations for the Tambora eruption. An increased meridional stratospheric temperature gradient is often assumed to be the cause of the vortex strengthening. The position of the maximum temperature anomaly gradient is located, however, at approximately 30°N, far away from the polar vortex . Hence, the vortex strengthening is caused only indirectly by the changed temperature gradient which first produces a subtropical wind anomaly in early winter. This leads planetary waves propagating more equatorward causing finally the vortex strengthening. The simulated response to the weaker eruptions of Krakatau and Pinatubo is also a slight average strengthening of the polar vortex, but individual ensemble members differ strongly indicating that internal variability can mask the impact on the polar vortex in the NH post-eruption winter under such moderate eruption strengths. The large forcing of the Tambora eruption does not only cause a mean vortex strengthening but also a reduction of the ensemble variability of the vortex.

  17. Active Volcanic Plumes on Io

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This color image, acquired during Galileo's ninth orbit around Jupiter, shows two volcanic plumes on Io. One plume was captured on the bright limb or edge of the moon (see inset at upper right), erupting over a caldera (volcanic depression) named Pillan Patera after a South American god of thunder, fire and volcanoes. The plume seen by Galileo is 140 kilometers (86 miles) high and was also detected by the Hubble Space Telescope. The Galileo spacecraft will pass almost directly over Pillan Patera in 1999 at a range of only 600 kilometers (373 miles).

    The second plume, seen near the terminator (boundary between day and night), is called Prometheus after the Greek fire god (see inset at lower right). The shadow of the 75-kilometer (45- mile) high airborne plume can be seen extending to the right of the eruption vent. The vent is near the center of the bright and dark rings. Plumes on Io have a blue color, so the plume shadow is reddish. The Prometheus plume can be seen in every Galileo image with the appropriate geometry, as well as every such Voyager image acquired in 1979. It is possible that this plume has been continuously active for more than 18 years. In contrast, a plume has never been seen at Pillan Patera prior to the recent Galileo and Hubble Space Telescope images.

    North is toward the top of the picture. The resolution is about 6 kilometers (3.7 miles) per picture element. This composite uses images taken with the green, violet and near infrared filters of the solid state imaging (CCD) system on NASA's Galileo spacecraft. The images were obtained on June 28, 1997, at a range of more than 600,000 kilometers (372,000 miles).

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page

  18. G-EVER Activities and the Next-generation Volcanic Hazard Assessment System

    NASA Astrophysics Data System (ADS)

    Takarada, S.

    2013-12-01

    The Asia-Pacific Region Global Earthquake and Volcanic Eruption Risk Management (G-EVER) is a consortium of Asia-Pacific geohazard research institutes that was established in 2012. G-EVER aims to formulate strategies to reduce the risks of disasters worldwide caused by the occurrence of earthquakes, tsunamis and volcanic eruptions. G-EVER is working on enhancing collaboration, sharing of resources, and making information on the risks of earthquakes and volcanic eruptions freely available and understandable. The 1st G-EVER International Symposium was held in Tsukuba, Japan in March 11, 2013. The 2nd Symposium is scheduled in Sendai, Tohoku Japan, in Oct. 19-20, 2013. Currently, 4 working groups were proposed in the G-EVER Consortium. The next-generation volcano hazard assessment WG is developing a useful system for volcanic eruption prediction, risk assessment, and evacuation at various eruption stages. The assessment system is based on volcanic eruption history datasets, volcanic eruption database, and numerical simulations. Volcanic eruption histories including precursor phenomena leading to major eruptions of active volcanoes are very important for future prediction of volcanic eruptions. A high quality volcanic eruption database, which contains compilations of eruption dates, volumes, and types, is important for the next-generation volcano hazard assessment system. Proposing international standards on how to estimate the volume of volcanic products is important to make a high quality volcanic eruption database. Spatial distribution database of volcanic products (e.g. tephra and pyroclastic flow distributions), encoded into a GIS based database is necessary for more precise area and volume estimation and risk assessments. The volcanic eruption database is developed based on past eruption results, which only represents a subset of possible future scenarios. Therefore, numerical simulations with controlled parameters are needed for more precise volcanic eruption

  19. 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.

  20. 3-D Numerical Modeling Perspectives on Lightning Generation in Volcanic Eruption Clouds

    NASA Astrophysics Data System (ADS)

    Van Eaton, A. R.; Behnke, S. A.; Herzog, M.

    2014-12-01

    Although numerous charging mechanisms have been implicated in the formation of volcanic lightning, recent insights from lightning mapping arrays indicate that vent charging (produced at or near the volcanic source) creates electrical discharges that are distinct from lightning initiated in the airborne plume during transport away from the vent. Previous work has suggested that turbulent structure and formation of hydrometeors, including rain, graupel and ash aggregates, are likely to play important roles in the plume charging process. We examine these phenomena with 3D large-eddy simulations of volcanic plume development that include cloud microphysics, using the Active Tracer High-resolution Atmospheric Model (ATHAM). Three relatively recent eruptions are targeted, each with different plume heights, degrees of wind interaction, and amounts of surface water interaction. We have compared the simulated evolution of turbulence and precipitation formation with data from lightning mapping arrays to address the following question - what can lightning tell us about the initiation and development of a volcanic plume in near-real time?

  1. Global link between deformation and volcanic eruption quantified by satellite imagery.

    PubMed

    Biggs, J; Ebmeier, S K; Aspinall, W P; Lu, Z; Pritchard, M E; Sparks, R S J; Mather, T A

    2014-01-01

    A key challenge for volcanological science and hazard management is that few of the world's volcanoes are effectively monitored. Satellite imagery covers volcanoes globally throughout their eruptive cycles, independent of ground-based monitoring, providing a multidecadal archive suitable for probabilistic analysis linking deformation with eruption. Here we show that, of the 198 volcanoes systematically observed for the past 18 years, 54 deformed, of which 25 also erupted. For assessing eruption potential, this high proportion of deforming volcanoes that also erupted (46%), together with the proportion of non-deforming volcanoes that did not erupt (94%), jointly represent indicators with 'strong' evidential worth. Using a larger catalogue of 540 volcanoes observed for 3 years, we demonstrate how this eruption-deformation relationship is influenced by tectonic, petrological and volcanic factors. Satellite technology is rapidly evolving and routine monitoring of the deformation status of all volcanoes from space is anticipated, meaning probabilistic approaches will increasingly inform hazard decisions and strategic development.

  2. Global link between deformation and volcanic eruption quantified by satellite imagery.

    PubMed

    Biggs, J; Ebmeier, S K; Aspinall, W P; Lu, Z; Pritchard, M E; Sparks, R S J; Mather, T A

    2014-01-01

    A key challenge for volcanological science and hazard management is that few of the world's volcanoes are effectively monitored. Satellite imagery covers volcanoes globally throughout their eruptive cycles, independent of ground-based monitoring, providing a multidecadal archive suitable for probabilistic analysis linking deformation with eruption. Here we show that, of the 198 volcanoes systematically observed for the past 18 years, 54 deformed, of which 25 also erupted. For assessing eruption potential, this high proportion of deforming volcanoes that also erupted (46%), together with the proportion of non-deforming volcanoes that did not erupt (94%), jointly represent indicators with 'strong' evidential worth. Using a larger catalogue of 540 volcanoes observed for 3 years, we demonstrate how this eruption-deformation relationship is influenced by tectonic, petrological and volcanic factors. Satellite technology is rapidly evolving and routine monitoring of the deformation status of all volcanoes from space is anticipated, meaning probabilistic approaches will increasingly inform hazard decisions and strategic development. PMID:24699342

  3. Lidar Observations of Stratospheric Aerosol Layer After the Mt. Pinatubo Volcanic Eruption

    NASA Technical Reports Server (NTRS)

    Nagai, Tomohiro; Uchino, Osamu; Fujimoto, Toshifumi

    1992-01-01

    The volcano Mt. Pinatubo located on the Luzon Island, Philippines, had explosively erupted on June 15, 1991. The volcanic eruptions such as volcanic ash, SO2 and H2O reached into the stratosphere over 30 km altitude by the NOAA-11 satellite observation and this is considered one of the biggest volcanic eruptions in this century. A grandiose volcanic eruption influences the atmosphere seriously and causes many climatic effects globally. There had been many impacts on radiation, atmospheric temperature and stratospheric ozone after some past volcanic eruptions. The main cause of volcanic influence depends on stratospheric aerosol, that stay long enough to change climate and other meteorological conditions. Therefore it is very important to watch stratospheric aerosol layers carefully and continuously. Standing on this respect, we do not only continue stratospheric aerosol observation at Tsukuba but also have urgently developed another lidar observational point at Naha in Okinawa Island. This observational station could be thought valuable since there is no lidar observational station in this latitudinal zone and it is much nearer to Mt. Pinatubo. Especially, there is advantage to link up these two stations on studying the transportation mechanism in the stratosphere. In this paper, we present the results of lidar observations at Tsukuba and Naha by lidar systems with Nd:YAG laser.

  4. Space-borne constraints on SO2 fluxes for recent volcanic eruptions in 2011

    NASA Astrophysics Data System (ADS)

    Theys, N.; Campion, R.; Clarisse, L.; Brenot, H.; van Gent, J.; Coheur, P.; Van Roozendael, M.; Tait, S.; Ferrucci, F.

    2012-04-01

    Magmatic gases (H2O, CO2, sulphur and halogenated species) are the driving forces of volcanic eruptions. These emissions can strongly impact the local biosphere (through acid deposition) and also affect significantly the chemical composition of the atmosphere and climate. Sulphur dioxide (SO2) measurements have been used to characterize and monitor volcanic activity for decades. However, remote-sensing methods based on absorption spectroscopy generally provide integrated concentration of already dispersed plumes of SO2. In the last years, consolidated measurements of total emission fluxes of SO2 have been made possible for active degassing volcanoes using ground-based measurements. For non-monitored volcanoes or explosive volcanic eruptions, space-based measurements of SO2 are more adequate but unfortunately fluxes estimates are sparse. The motivation for this study is an effort to constrain volcanic SO2 fluxes using satellite measurements of dispersed and large-scale plumes of SO2. We combine different approaches and investigate the temporal evolution of the total emissions of SO2 for a number of recent volcanic events in 2011: Nyamuragira (Congo), Nabro (Eritrea) and Puyehue (Chili). High spectral resolution satellite instruments operating both in the UV-visible (OMI/Aura and GOME-2/MetOp-A) and thermal Infrared (IASI/MetOp-A) spectral ranges are used in a synergistic way. Although the primary objective of this study is the calculation of SO2 fluxes, it also enables to assess the consistency of the SO2 products from the different sensors used. Moreover, our estimates of SO2 fluxes are confronted to magma fluxes constraints obtained from independent thermal measurements. This work is performed in the frame of the European Volcano Observatory Space Services (EVOSS) EU FP7 project whose aim is to develop and demonstrate a portfolio of GMES Downstream Services, based on Earth Observation data products, to monitor volcanic activity and relevant hazards at a global

  5. Global detection of explosive volcanic eruptions with the World Wide Lightning Location Network (WWLLN) and application to aviation safety (Invited)

    NASA Astrophysics Data System (ADS)

    Ewert, J. W.; Holzworth, R. H.; Diefenbach, A. K.

    2010-12-01

    The hazards of volcanic ash to modern aviation are now widely known, and there is a concerted global effort on the part of volcano observatories, meteorological services, and civil aviation authorities to keep aircraft out of harm’s way. A major issue with providing rapid notification of dangerous eruptions is that only about 50% of the world's volcanoes that currently threaten air operations have any sort of ground-based, real-time monitoring; thus, timely detection of explosive eruptions is more difficult owing to reliance on satellite remote sensing. We have been evaluating the World Wide Lightning Location Network (WWLLN, see http://wwlln.net) as a tool to detect volcanogenic lightning associated with explosive eruptions worldwide to aid rapid eruption reporting for aviation. The WWLLN has a data latency of one minute and thus can detect and report volcanogenic lightning in near-real time. We compared explosive volcanic activity worldwide (data from the Smithsonian’s Global Volcanism Program, volcano observatory reports, Volcanic Ash Advisory Center (VAAC) reports, and ancillary data sources) with the entire catalog of WWLLN data for 2008 and 2009 to determine the eruption-detection capabilities of the system. Duration and number of WWLLN lightning detections is positively correlated with eruption magnitude. In 2008 the WWLLN detected lightning from all eruptions VEI 4 or larger (Chaiten, Chile; Kasatochi and Okmok, Alaska, USA), as well as four out of six of the ~VEI 3 and two ~VEI 2 eruptions. In 2009 the WWLLN detected the single VEI 4 eruption (Sarychev Peak, Kurile Islands, Russia), four out six of the ~VEI 3 and a single VEI 2 eruption. At volcanoes where eruption-onset times are well determined by seismic or remote sensing means, lightning flashes started within 4 to 58 minutes of eruption onset. Lightning was detected from eruptions that produced ash clouds with heights that ranged from approximately 1-15 km above the vent, with most >9 km. Detected

  6. A cellular automaton to model magma/crust interactions and volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Sanchez, L.; Shcherbakov, R.

    2012-12-01

    Volcanic eruptions are the outcomes of complex dynamical interactions between magma and the Earth's crust and are characterized by non-trivial temporal correlations. It is of major importance to study the processes involved in magma ascent within the crust which can lead to a better under-standing of the failure mechanism that leads to an eruption. In a previous study, we showed that the interevent time distributions of volcanic eruptions were characterized by a universal behavior, independent of the type of volcanism and geographical location. The distribution for interevent times between successive eruptions were shown to deviate from the simple Poisson statistics. Instead, occurrence of volcanic eruptions can be modeled by a log-normal distribution. In the present work, we investigate the interactions between the magma and the host rock at the microscopic level using a cellular automaton approach. We consider a two-dimensional system on a rectangular lattice consisting of the magma chamber and the overlying crust. The magma particles coming from the chamber rise through the crust by damaging it to its failure point, and eventually reach the surface resulting in an eruption. While not damaged by magma, the crust can heal with time and fractures will close. The amount of damage that a particle can afflict on a crustal site and the healing capability of the crust are two model parameters and mimic various crustal settings. We consider two different definitions of the eruption sizes: i) only the magma in the vertical fractures directly under the eruption point is considered to define the eruption; ii) the entire fracture network (vertical and horizontal) filled with magma and connected to the eruption point is considered to define the eruption. In order to investigate further what controls the explosivity of eruptions, we introduce a binary system to model the magma and dissolved gases: magma and dissolved gases which are characterized by dierent damage capacities

  7. Volcanic eruption crisis and the challenges of geoscience education in Indonesia

    NASA Astrophysics Data System (ADS)

    Hariyono, E.; Liliasari, Tjasyono, B.; Madlazim

    2016-02-01

    The study aims was to describe of the profile of geoscience education conducted at the institution of teacher education for answer challenges of volcanic eruption crisis in Indonesia. The method used is descriptive analysis based on result of test and interview to 31 students of physics pre-service teachers about volcanoes through field study. The results showed that the students have a low understanding of volcanic material and there are several problems associated with the volcanoes concept. Other facts are geoscience learning does not support to the formation of geoscience knowledge and skills, dominated by theoretical studies and less focused on effort to preparing students towards disasters particularly to the volcanic eruption. As a recommendation, this require to restructuring geoscience education so as relevant with the social needs. Through courses accordingly, we can greatly help student's physics prospective teacher to improve their participations to solve problems of volcanic eruption crisis in the society.

  8. Modeling the statistical behaviour of volcanic eruptions using a cellular automaton

    NASA Astrophysics Data System (ADS)

    Sanchez, Laura; Shcherbakov, Robert

    2013-04-01

    Volcanic eruptions are a complex dynamical system characterized by non-trivial temporal correlations. Understanding the processes involved in magma ascent within the crust as well as the interactions between magma and crust and the failure mechanism that leads to an eruption are crucial in order to develop better hazard assessment techniques. In a previous study, we showed that the interevent time distributions of volcanic eruptions are characterized by a universal behavior, independent of the type of volcanism and geographical location. The distribution for eruptions with a large interevent time seems to deviate from the simple Poisson statistics. In order to investigate the interactions between the magma and the host rock within the crust, we developed a cellular automaton model which mimics those interactions at the microscopic level. The results from a preliminary analysis presented at the AGU fall meeting 2012 showed a good agreement between the model results and the world eruption data. We observe 2 regimes of eruptions that could be representative of close and open conduits systems. Here, we explore the capabilities of the model on larger lattice sizes and longer time intervals. We consider two different fracture profiles within the crust. (1)- Only the vertical fractures directly under the eruption point are considered in the eruption; (2)- the entire fracture network (vertical and horizontal) under the eruption point is considered in the eruption. We also introduce different particle types: magma and dissolved gas, in order to take into account the explosivity of eruptions. We then perform a statistical analysis to compare the model results with the world eruption data. This model allows us to describe the dynamics of complex magma interactions using a minimum number of parameters.

  9. Determining volcanic eruption styles on Earth and Mars from crystallinity measurements.

    PubMed

    Wall, Kellie T; Rowe, Michael C; Ellis, Ben S; Schmidt, Mariek E; Eccles, Jennifer D

    2014-01-01

    Both Earth and Mars possess different styles of explosive basaltic volcanism. Distinguishing phreatomagmatic eruptions, driven by magma-water interaction, from 'magmatic' explosive eruptions (that is, strombolian and plinian eruptions) is important for determining the presence of near-surface water or ice at the time of volcanism. Here we show that eruption styles can be broadly identified by relative variations in groundmass or bulk crystallinity determined by X-ray diffraction. Terrestrial analogue results indicate that rapidly quenched phreatomagmatic ejecta display lower groundmass crystallinity (<35%) than slower cooling ejecta from strombolian or plinian eruptions (>40%). Numerical modelling suggests Martian plinian eruptive plumes moderate cooling, allowing 20-30% syn-eruptive crystallization, and thus reduce the distinction between eruption styles on Mars. Analysis of Mars Curiosity rover CheMin X-ray diffraction results from Gale crater indicate that the crystallinity of Martian sediment (52-54%) is similar to pyroclastic rocks from Gusev crater, Mars, and consistent with widespread distribution of basaltic strombolian or plinian volcanic ejecta.

  10. Determining volcanic eruption styles on Earth and Mars from crystallinity measurements.

    PubMed

    Wall, Kellie T; Rowe, Michael C; Ellis, Ben S; Schmidt, Mariek E; Eccles, Jennifer D

    2014-01-01

    Both Earth and Mars possess different styles of explosive basaltic volcanism. Distinguishing phreatomagmatic eruptions, driven by magma-water interaction, from 'magmatic' explosive eruptions (that is, strombolian and plinian eruptions) is important for determining the presence of near-surface water or ice at the time of volcanism. Here we show that eruption styles can be broadly identified by relative variations in groundmass or bulk crystallinity determined by X-ray diffraction. Terrestrial analogue results indicate that rapidly quenched phreatomagmatic ejecta display lower groundmass crystallinity (<35%) than slower cooling ejecta from strombolian or plinian eruptions (>40%). Numerical modelling suggests Martian plinian eruptive plumes moderate cooling, allowing 20-30% syn-eruptive crystallization, and thus reduce the distinction between eruption styles on Mars. Analysis of Mars Curiosity rover CheMin X-ray diffraction results from Gale crater indicate that the crystallinity of Martian sediment (52-54%) is similar to pyroclastic rocks from Gusev crater, Mars, and consistent with widespread distribution of basaltic strombolian or plinian volcanic ejecta. PMID:25277152

  11. The Extremes of Volcanic Activity: Earth and Jupiter's Moon Io

    NASA Astrophysics Data System (ADS)

    Lowes, L. L.; Lopes, R.

    2004-12-01

    Jupiter's moon Io is the solar system's most volcanically active body, and the only place that magmatic volcanic eruptions have been observed beyond Earth. One of the first images of Io obtained by NASA's Voyager 1 spacecraft in 1979 shows a plume above one of its volcanoes. The NASA Voyager and Galileo spacecraft imaged many explosive eruptions of plumes and deposits - which travel hundreds of kilometers (farther than on the Earth or the Moon). Very hot lavas that are erupting from volcanic vents on Io may be similar to lavas that erupted on Earth billions of years ago. Understanding the physical processes driving volcanic eruptions is important for the understanding of terrestrial volcanoes, not only because of their potential hazards, but also as geologic resources, biologic environments, and for their role in shaping the surface of Earth and other planets. Volcanic eruptions are perhaps the most dramatic events on Earth, and are of intrinsic interest to students, youth, and adults. Topics involving volcanoes are a part of the national science education benchmarks for understanding the Earth's composition and structure for grades 6-8 (the process of creating landforms) and grades 9-12 (the effects of movement of crustal plates). Natural events on Earth coupled with exciting discoveries in space can serve to heighten the awareness of these phenomena and provide learning opportunities for real world applications of science. Educational applications for youth to compare volcanic activity on Io and Earth have been done through NASA-sponsored field trip workshops to places such as Yellowstone National Park (allowing educators to experience environments similar to those on other worlds), targeted classroom and hands-on activities, special interest books, and other resources. A sampling of such activities will be presented, and discussion invited on other related developmentally appropriate resources and activities.

  12. Palaeomagnetic refinement of the eruption ages of Holocene lava flows, and implications for the eruptive history of the Tongariro Volcanic Centre, New Zealand

    NASA Astrophysics Data System (ADS)

    Greve, Annika; Turner, Gillian M.; Conway, Chris E.; Townsend, Dougal B.; Gamble, John A.; Leonard, Graham S.

    2016-11-01

    We present a detailed palaeomagnetic study from 35 sites on Holocene lava flows of the Tongariro Volcanic Centre, central North Island, New Zealand. Prior to the study the eruption ages of these flows were constrained to within a few thousand years by recently published high-precision 40Ar/39Ar geochronological data and tephrostratigraphic controls. Correlation of flow mean palaeomagnetic directions with a recently published continuous sediment record from Lake Mavora, Fiordland, allows us to reduce the age uncertainty to 300-500 yr in some cases. Our refined ages significantly improve the chronology of Holocene effusive eruptions of the volcanoes of the Tongariro Volcanic Centre. For instance, differences in the palaeomagnetic directions recorded by lavas from the voluminous Iwikau and Rangataua members suggest that individual effusive periods lasted up to thousands of years and that these bursts have been irregularly spaced over time. While over the last few millennia the effusive eruptive activity from Mt Ruapehu has been relatively quiet, the very young age (200-500 BP) of a Red Crater sourced flow suggests that effusive activity around Mt Tongariro lasted into the past few centuries. This adds an important hazard context to the historical record, which has otherwise comprised frequent relatively small, tephra producing, explosive eruptions without the production of lava flows.

  13. Spaceborne Synthetic Aperture Radar (SAR) Doppler anomalies due to volcanic eruption induced phenomena

    NASA Astrophysics Data System (ADS)

    de Michele, Marcello; Raucoules, Daniel; Minet, Christian

    2015-04-01

    In the frame of the EU funded "MEDSUV" supersite project, we use multiple SAR data to investigate Doppler anomalies in the SAR signal occurring during volcanic eruptions. In Synthetic Aperture Radar, variations in the Electro Magnetic Waves travel time results in a change in the Doppler frequency that adds up to the one that is naturally generated by the relative motion between the platform and the ground targets. Within the SAR system, frequencies modulations control the image focusing along the two fundamental SAR directions, the azimuth (i.e. the platform motion direction) and the range (i. e. the sensor looking direction). During the synthetic aperture process (the so called image focusing) a target on the surface is seen along different paths. In standard focusing processing it is assumed both that ground targets are stationary and that between the sensor and the target the medium is the vacuum or a totally homogeneous medium. Therefore, if there is a significant path delay variation along the paths to a specific target this can result either in image defocusing or in pixel misregistration or both. It has been shown that SAR Doppler history anomalies can occur over volcanic areas. The goal of this study is to highlight Doppler history anomalies occurring during the SAR image formation over active volcanoes on a number of test cases. To do so, we apply a sub-aperture cross correlation algorithm on Single Look Complex data. Practically, we measure any pixel misregistration between two sub-looks of the same SAR acquisition. If a pixel shift occurs, it means that the expected radar wave path has been lengthened (or shortened) during the time when ground surface scatterers were illuminated by the sensor radiation either by a ground feature velocity (e. g. water flows, vehicles) or it is refracted by a strong medium discontinuity in the air (volcanic ash plume?). If a Doppler history anomaly is detected by the sub-aperture cross correlation, we try to explore

  14. Effects of Volcanic Eruptions on Climate in Inner Asia from 600 BCE to 2015 CE

    NASA Astrophysics Data System (ADS)

    Zhu, J. L.; Hessl, A. E.; Leland, C.; Byambasuren, O.; Anchukaitis, K. J.; Pederson, N.

    2015-12-01

    Volcanic eruptions have strongly influenced regional and global climate on many time scales. However, past studies have focused solely on the temperature variability of climate due to eruptions, using modern eruptions with the aid of satellite records. By using tree-ring data from a variety of sites that are temperature or moisture limited, it may be possible to attain a more complete understanding of the climatic effects of large eruptions from the past 2600 years. We used existing tree-ring data from Mongolia to understand how volcanic eruptions influence different climatic variables (temperature, moisture, and solar irradiance) in Inner Asia. This study, part of a larger research project on human ecology of Inner Asia, focuses on past volcanic eruptions ( 600 BCE to 2015 CE) at three sites in north central Mongolia: Solongotyn Davaa (48.3°N, 98.93°E), a temperature limited site, Khorgo Lava (48.17°N, 99.87°E), and Urgaat Lava (46.40°N, 101.46°E), both moisture limited sites. We collected more than 200 tree-ring samples of Siberian pine (Pinus sibirica) from the three sites. We used the Grid Analysis and Display System to run composite analyses using Climatic Research Unit temperature and precipitation data to test how modern eruptions between 1961 and 1999 influenced temperature and precipitation regimes in Mongolia. Four eruptions were analyzed and both composite analyses suggest that each variable is altered by volcanic eruptions during the 1 to 2 years following an eruption. We then used superposed epoch analysis to evaluate how past eruptions affect regional climate in Mongolia by separating temperature and precipitation variables. Our results indicate that most of Mongolia experienced 0.5°C cooler and dryer conditions following major eruptions. This research shows that tree-ring data is invaluable to studying volcanic eruptions by extending the time range of eruptions available to study and providing a more complete understanding of how they affect

  15. 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

  16. ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA

    SciTech Connect

    C. Harrington

    2004-10-25

    The purpose of this model report is to provide documentation of the conceptual and mathematical model (Ashplume) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. These aspects of volcanism-related dose calculation are described in the context of the entire igneous disruptive events conceptual model in ''Characterize Framework for Igneous Activity'' (BSC 2004 [DIRS 169989], Section 6.1.1). The Ashplume conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The Ashplume mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report update the previous documentation of the Ashplume mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application (TSPA-LA) igneous scenarios. This model report also documents the redistribution model product outputs based on analyses to support the conceptual model. In this report, ''Ashplume'' is used when referring to the atmospheric dispersal model and ''ASHPLUME'' is used when referencing the code of that model. Two analysis and model reports provide direct inputs to this model report, namely ''Characterize Eruptive Processes at Yucca Mountain, Nevada and Number of Waste Packages Hit by Igneous Intrusion''. This model report provides direct inputs to

  17. Active and Recent Volcanism and Hydrogeothermal Activity on Mars

    NASA Astrophysics Data System (ADS)

    Edgett, Kenneth S.; Cantor, B. A.; Harrison, T. N.; Kennedy, M. R.; Lipkaman, L. J.; Malin, M. C.; Posiolova, L. V.; Shean, D. E.

    2010-10-01

    There are no active volcanoes or geysers on Mars today, nor in the very recent past. Since 1997, we have sought evidence from targeted narrow angle camera images and daily, global wide angle images for active or very recent (decades to < 10 Ma) volcanism or hydrogeothermal events on Mars. Despite > 11 years of daily global imaging and coverage of > 60% of Mars at ≤ 6 m/pixel (with the remaining < 40% largely outside of volcanic regions), we have found no such evidence, although one lava field in Aeolis (5°N, 220°W) stands out as possibly the site of the most recent volcanism. Authors of impact crater size-frequency studies suggest some volcanic landforms on Mars are as young as tens to hundreds of Ma. This interpreted youth has implications for understanding the internal geophysical state of Mars and has encouraged those seeking sources for trace gases (methane) in the atmosphere and those seeking "warm havens for life” (Jakosky 1996, New Scientist 150, 38-42). We targeted thousands of Mars Global Surveyor (MGS) MOC and Mars Reconnaissance Orbiter (MRO) CTX (and HiRISE) images to examine volcanic regions; we also studied every MGS MOC and MRO MARCI wide angle image. For evidence of active volcanism, we sought eruption plumes, new vents, new tephra deposits, and new volcanogenic flows not observed in earlier images. For recent volcanism, we sought volcanogenic flows with zero or few superposed impact craters and minimal regolith development or superposed eolian sediment. Targets included all volcanic landforms identified in research papers as "recent” as well as areas speculated to have exhibited eruptive plumes. An independent search for endogenic heat sources, a key Mars Odyssey THEMIS objective, has also not produced a positive result (Christensen et al. 2005, P24A-01, Eos, Trans. Am. Geophys. Union 86/52).

  18. Identifying the volcanic eruption depicted in a neolithic painting at Çatalhöyük, Central Anatolia, Turkey.

    PubMed

    Schmitt, Axel K; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M

    2014-01-01

    A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with (14)C ages for cultural strata at Çatalhöyük, including level VII containing the "map" mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard.

  19. Identifying the Volcanic Eruption Depicted in a Neolithic Painting at Çatalhöyük, Central Anatolia, Turkey

    PubMed Central

    Schmitt, Axel K.; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M.

    2014-01-01

    A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with 14C ages for cultural strata at Çatalhöyük, including level VII containing the “map” mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard. PMID:24416270

  20. Identifying the volcanic eruption depicted in a neolithic painting at Çatalhöyük, Central Anatolia, Turkey.

    PubMed

    Schmitt, Axel K; Danišík, Martin; Aydar, Erkan; Şen, Erdal; Ulusoy, İnan; Lovera, Oscar M

    2014-01-01

    A mural excavated at the Neolithic Çatalhöyük site (Central Anatolia, Turkey) has been interpreted as the oldest known map. Dating to ∼6600 BCE, it putatively depicts an explosive summit eruption of the Hasan Dağı twin-peaks volcano located ∼130 km northeast of Çatalhöyük, and a birds-eye view of a town plan in the foreground. This interpretation, however, has remained controversial not least because independent evidence for a contemporaneous explosive volcanic eruption of Hasan Dağı has been lacking. Here, we document the presence of andesitic pumice veneer on the summit of Hasan Dağı, which we dated using (U-Th)/He zircon geochronology. The (U-Th)/He zircon eruption age of 8.97±0.64 ka (or 6960±640 BCE; uncertainties 2σ) overlaps closely with (14)C ages for cultural strata at Çatalhöyük, including level VII containing the "map" mural. A second pumice sample from a surficial deposit near the base of Hasan Dağı records an older explosive eruption at 28.9±1.5 ka. U-Th zircon crystallization ages in both samples range from near-eruption to secular equilibrium (>380 ka). Collectively, our results reveal protracted intrusive activity at Hasan Dağı punctuated by explosive venting, and provide the first radiometric ages for a Holocene explosive eruption which was most likely witnessed by humans in the area. Geologic and geochronologic lines of evidence thus support previous interpretations that residents of Çatalhöyük artistically represented an explosive eruption of Hasan Dağı volcano. The magmatic longevity recorded by quasi-continuous zircon crystallization coupled with new evidence for late-Pleistocene and Holocene explosive eruptions implicates Hasan Dağı as a potential volcanic hazard. PMID:24416270

  1. Volcanic Eruptions, Landscape Disturbance, and Potential Impacts to Marine and Terrestrial Ecosystems in Alaska: An Example from the August 2008 Eruption of Kasatochi Volcano

    NASA Astrophysics Data System (ADS)

    Waythomas, C. F.; Drew, G. S.

    2011-12-01

    The magnitude, style, and sometimes-prolonged nature of volcanic activity in Alaska has had significant impact on ecological habitat. The accumulation of volcaniclastic deposits during eruptions have destroyed or altered areas important to the success of various species and it may take years to decades for landforms and surfaces to recover and become habitable again. Kasatochi volcano, in the Aleutian Islands of Alaska, erupted explosively on August 7-8, 2008 and the rich nesting habitat for several species of seabirds on the island was completely destroyed. The eruption produced thick pyroclastic fall and flow deposits and several SO2 rich ash-gas plumes that reached 14 to 18 km above sea level. Pyroclastic deposits are several tens of meters thick, blanket the entire island, and initially extended seaward to increase the diameter of the island by about 800 m. Wave and gully erosion have modified these deposits and have exhumed some pre-eruption surfaces. Analysis of surface erosional features observed in satellite and time-lapse camera images and field studies have shown that by September 2009, gully erosion removed 300,000-600,000 m3 of mostly fine-grained volcanic sediment from the volcano flanks and much of this has reached the ocean. Sediment yield estimates from two representative drainage basins are about 104 m3km-2yr-1 and are comparable to sediment yields at other active volcanoes outside of Alaska. Coastal erosion rates at Kasatochi are as high as 80-140 myr-1 and parts of the northern coastline have already been eroded back to pre-eruption positions. As of March, 2011 about 72% of the material emplaced beyond the pre-eruption coastline on the northern sector of the island has been removed by wave erosion. Parts of the southern coastline have prograded beyond the post-eruption shoreline as a result of long-shore transport of sediment from north to south. As of March 2011, the total volume of material eroded by wave action was about 107 m3. The preferred

  2. Time and space variations in magmatic and phreatomagmatic eruptive processes at Easy Chair (Lunar Crater Volcanic Field, Nevada, USA)

    NASA Astrophysics Data System (ADS)

    Valentine, Greg A.; Cortés, Joaquín A.

    2013-09-01

    The products of monogenetic volcanoes often record complex sequences of eruptive processes. Easy Chair volcano (Lunar Crater Volcanic Field, Nevada, USA) was formed by a monogenetic eruption along a ˜2.5-km-long series of en echelon fissure vents. Hawaiian to Strombolian fountains along the fissures dominated initial activity, producing a series of agglomerate ramparts. Focusing of eruptive activity to two central vents and the formation of two overlapping scoria cones followed the early phase. Fountain-fed lavas from those cones merged to form a channel that fed lava onto a flow field at the foot of the cones. Focusing of subsurface magma flow toward the central conduits may have reduced magma flux in the remaining fissures, and the southern segment(s) entered a phase of phreatomagmatic explosions that destroyed the early agglomerate rampart and formed a maar and tephra ring composed of lapilli tuff rich in clasts derived from pre-Easy Chair lavas and early agglomerates. The eruption closed with a minor phase of magmatic activity that deposited scoria lapilli and bombs on top of the phreatomagmatic deposits. The eruptive sequence indicates that relatively low hazard Strombolian to Hawaiian activity can be replaced by more hazardous phreatomagmatic explosions well into a monogenetic eruption.

  3. A numeral model to simulate the chemical processing of volcanic ejecta in eruption plumes and clouds

    NASA Astrophysics Data System (ADS)

    Hoshyaripour, Gholam Ali; Hort, Marthias; Brasseur, Guy

    2016-04-01

    Volcanic eruptions inject tremendous amount of gases and particles into the atmosphere that can notably affect different components of the climate system. The scale of such impacts strongly depends on the eruption magnitude as well as the physicochemical properties of the erupted material, which are mainly shaped during the atmospheric transport within the eruption plume and cloud. For instance, the radiative forcing of an eruption through backscattering the incoming solar radiation depends on the amount and properties of the sulfate aerosols formed as the result of in-cloud processes including chemical conversion of volcanic SO2 to sulfate. The rate, pathway and efficiency of this conversion can therefore significantly influence the radiative forcing posed by the eruption. Models that can simulate such in-plume and in-cloud processes are rare. Here we present the framework and initial results of a numerical model that simulates the chemical interaction of gas, ash and aerosols within the volcanic eruption plumes and clouds. The chemical mechanism takes into account the gaseous and aqueous chemistry as well as the gas-aerosol partitioning within a fully-coupled scheme. In other words, it is capable of modeling the changes in the gas, liquid and solid phase separately as well as the interactions between phases. For instance, the results show that the ash dissolution reduces the acidity of its liquid coating and thus, enhances the scavenging of SO2 and HCl. The potential application of the model in volcanology, geochemistry and atmospheric sciences are discussed.

  4. Historical evidence for a connection between volcanic eruptions and climate change

    NASA Technical Reports Server (NTRS)

    Rampino, Michael R.

    1991-01-01

    The times of historical volcanic aerosol clouds were compared with changes in atmospheric temperatures on regional, hemispheric, and global scales. These involve either a direct comparison of individual significant eruption years with temperature records, or a comparison of eruption years with composited temperature records for several years before and after chosen sets of eruptions. Some studies have challenged the connection between individual eruptions and climate change. Mass and Portman (1989) recently suggested that the volcanic signal was present, but smaller than previously thought. In a study designed to test the idea that eruptions could cause small changes in climate, Hansen and other (1978) chose one of the best monitored eruptions at the time, the 1963 eruption of Agung volcano on the island of Bali. Using a simple radiation-balance model, in which an aerosol cloud in the tropics was simulated, this basic pattern of temperature change in the tropics and subtropics was reproduced. There may be natural limits to the atmospheric effects of any volcanic eruption. Self-limiting physical and chemical effects in eruption clouds were proposed. Model results suggest that aerosol microphysical processes of condensation and coagulation produce larger aerosols as the SO2 injection rate is increased. The key to discovering the greatest effects of volcanoes on short-term climate may be to concentrate on regional temperatures where the effects of volcanic aerosol clouds can be amplified by perturbed atmospheric circulation patterns, especially changes in mid-latitudes where meridional circulation patterns may develop. Such climatic perturbations can be detected in proxy evidence such as decreases in tree-ring widths and frost damage rings in climatically sensitive parts of the world, changes in treelines, weather anomalies such as unusually cold summers, severity of sea-ice in polar and subpolar regions, and poor grain yields and crop failures.

  5. 2009 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Girina, Olga A.; Chibisova, Marina; Rybin, Alexander

    2014-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, volcanic unrest, and reports of unusual activity at or near eight separate volcanic centers in Alaska during 2009. The year was highlighted by the eruption of Redoubt Volcano, one of three active volcanoes on the western side of Cook Inlet and near south-central Alaska's population and commerce centers, which comprise about 62 percent of the State's population of 710,213 (2010 census). AVO staff also participated in hazard communication and monitoring of multiple eruptions at ten volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  6. 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

  7. 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.

  8. Estimating different eruptive style volcanic areas of Mars from NASA Martian Meteorites Compendium data

    NASA Astrophysics Data System (ADS)

    Mari, Nicola; Verrino, Miriam

    2016-04-01

    The geomorphological characteristics of the Martian surface suggest that both effusive and explosive eruptive behaviour occurred. We investigated whether data about magma viscosity could be extrapolated from Mars SNCs (Shergotty, Nakhla, and Chassigny classes) meteorites, by using available geochemical and petrographic data from the NASA Martian Meteorites Compendium. Viscosity was used to characterize how eruptive style could change in different volcanic regions of planet Mars. Data about composition and crystallinity of 41 SNCs meteorites were used and classified, avoiding meteorites with poor/incomplete database. We assumed Mars as a one-plate planet, fO2 = QFM, and H2O wt% = 0 for each sample. Collected data from the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES) identified the source regions for almost all the studied SNCs meteorites. As input for thermodynamic simulations we first needed to find the depth and pressure of the magmatic source for each meteorite sample through available Thermal Emission Imaging System (THEMIS). Data about average surface temperatures was used to establish whether a magmatic source is shallow or deep. Successively, we found the magma source depth (and pressure) by using the relationship with the heights of the volcanic edifice. The subsolidus equilibration temperatures found through petrologic softwares were used to calculate viscosity. Results indicate a crystallization temperature in a range from 1,120°C to 843°C, follow by a variation in viscosity from 101,43 to 105,97 Pa s. Viscosity seems to be higher in Tharsis, Elysium, Amazonis, and Syrtis Major regions than the remnant areas. According to past experimental studies about magma viscosity, we classified the eruptive style into effusive (101-103,5 Pa s), intermediate (103,5-104,5 Pa s), and explosive (104,5-106 Pa s). The Hellas Basin, Argyre Basin, Ganges Chasma, Eos Chasma, and Nili Fossae regions show an eruptive behaviour between effusive and intermediate

  9. Volcanic lightning and plume behavior reveal evolving hazards during the April 2015 eruption of Calbuco volcano, Chile

    NASA Astrophysics Data System (ADS)

    Van Eaton, Alexa R.; Amigo, Álvaro; Bertin, Daniel; Mastin, Larry G.; Giacosa, Raúl E.; González, Jerónimo; Valderrama, Oscar; Fontijn, Karen; Behnke, Sonja A.

    2016-04-01

    Soon after the onset of an eruption, model forecasts of ash dispersal are used to mitigate the hazards to aircraft, infrastructure, and communities downwind. However, it is a significant challenge to constrain the model inputs during an evolving eruption. Here we demonstrate that volcanic lightning may be used in tandem with satellite detection to recognize and quantify changes in eruption style and intensity. Using the eruption of Calbuco volcano in southern Chile on 22 and 23 April 2015, we investigate rates of umbrella cloud expansion from satellite observations, occurrence of lightning, and mapped characteristics of the fall deposits. Our remote sensing analysis gives a total erupted volume that is within uncertainty of the mapped volume (0.56 ± 0.28 km3 bulk). Observations and volcanic plume modeling further suggest that electrical activity was enhanced both by ice formation in the ash clouds >10 km above sea level and development of a low-level charge layer from ground-hugging currents.

  10. Volcanic lightning and plume behavior reveal evolving hazards during the April 2015 eruption of Calbuco Volcano, Chile

    DOE PAGES

    Van Eaton, Alexa R.; Behnke, Sonja Ann; Amigo, Alvaro; Bertin, Daniel; Mastin, Larry G.; Giacosa, Raul E.; Gonzalez, Jeronimo; Valderrama, Oscar; Fontijn, Karen

    2016-04-12

    Soon after the onset of an eruption, model forecasts of ash dispersal are used to mitigate the hazards to aircraft, infrastructure, and communities downwind. However, it is a significant challenge to constrain the model inputs during an evolving eruption. Here we demonstrate that volcanic lightning may be used in tandem with satellite detection to recognize and quantify changes in eruption style and intensity. Using the eruption of Calbuco volcano in southern Chile on 22 and 23 April 2015, we investigate rates of umbrella cloud expansion from satellite observations, occurrence of lightning, and mapped characteristics of the fall deposits. Our remotemore » sensing analysis gives a total erupted volume that is within uncertainty of the mapped volume (0.56 ± 0.28 km3 bulk). Furthermore, observations and volcanic plume modeling further suggest that electrical activity was enhanced both by ice formation in the ash clouds >10 km above sea level and development of a low-level charge layer from ground-hugging currents.« less

  11. Using volcanic tremor for eruption forecasting at White Island volcano (Whakaari), New Zealand

    NASA Astrophysics Data System (ADS)

    Chardot, Lauriane; Jolly, Arthur D.; M. Kennedy, Ben; Fournier, Nicolas; Sherburn, Steven

    2015-09-01

    Eruption forecasting is a challenging task because of the inherent complexity of volcanic systems. Despite remarkable efforts to develop complex models in order to explain volcanic processes prior to eruptions, the material Failure Forecast Method (FFM) is one of the very few techniques that can provide a forecast time for an eruption. However, the method requires testing and automation before being used as a real-time eruption forecasting tool at a volcano. We developed an automatic algorithm to issue forecasts from volcanic tremor increase episodes recorded by Real-time Seismic Amplitude Measurement (RSAM) at one station and optimised this algorithm for the period August 2011-January 2014 which comprises the recent unrest period at White Island volcano (Whakaari), New Zealand. A detailed residual analysis was paramount to select the most appropriate model explaining the RSAM time evolutions. In a hindsight simulation, four out of the five small eruptions reported during this period occurred within a failure window forecast by our optimised algorithm and the probability of an eruption on a day within a failure window was 0.21, which is 37 times higher than the probability of having an eruption on any day during the same period (0.0057). Moreover, the forecasts were issued prior to the eruptions by a few hours which is important from an emergency management point of view. Whereas the RSAM time evolutions preceding these four eruptions have a similar goodness-of-fit with the FFM, their spectral characteristics are different. The duration-amplitude distributions of the precursory tremor episodes support the hypothesis that several processes were likely occurring prior to these eruptions. We propose that slow rock failure and fluid flow processes are plausible candidates for the tremor source of these episodes. This hindsight exercise can be useful for future real-time implementation of the FFM at White Island. A similar methodology could also be tested at other

  12. The Volcano Disaster Assistance Program: Working with International Partners to Reduce the Risk from Volcanic Eruptions Worldwide

    NASA Astrophysics Data System (ADS)

    Mayberry, G. C.; Pallister, J. S.

    2015-12-01

    The Volcano Disaster Assistance Program (VDAP) is a joint effort between USGS and the U.S. Agency for International Development's (USAID) Office of U.S. Foreign Disaster Assistance (OFDA). OFDA leads and coordinates disaster responses overseas for the U.S. government and is a unique stakeholder concerned with volcano disaster risk reduction as an international humanitarian assistance donor. One year after the tragic eruption of Nevado del Ruiz in 1985, OFDA began funding USGS to implement VDAP. VDAP's mission is to reduce the loss of life and property and limit the economic impact from foreign volcano crises, thereby preventing such crises from becoming disasters. VDAP fulfills this mission and complements OFDA's humanitarian assistance by providing crisis response, capacity-building, technical training, and hazard assessments to developing countries before, during, and after eruptions. During the past 30 years, VDAP has responded to more than 27 major volcanic crises, built capacity in 12+ countries, and helped counterparts save tens of thousands of lives and hundreds of millions of dollars in property. VDAP responses have evolved as host-country capabilities have grown, but the pace of work has not diminished; as a result of VDAP's work at 27 volcanoes in fiscal year 2014, more than 1.3 million people who could have been impacted by volcanic activity benefitted from VDAP assistance, 11 geological policies were modified, 188 scientists were trained, and several successful eruption forecasts were made. VDAP is developing new initiatives to help counterparts monitor volcanoes and communicate volcanic risk. These include developing the Eruption Forecasting Information System (EFIS) to learn from compiled crisis data from 30 years of VDAP responses, creating event trees to forecast eruptions at restless volcanoes, and exploring the use of unmanned aerial systems for monitoring. The use of these new methods, along with traditional VDAP assistance, has improved VDAP

  13. 3-D high-speed imaging of volcanic bomb trajectory in basaltic explosive eruptions

    USGS Publications Warehouse

    Gaudin, D.; Taddeucci, J; Houghton, B. F.; Orr, Tim R.; Andronico, D.; Del Bello, E.; Kueppers, U.; Ricci, T.; Scarlato, P.

    2016-01-01

    Imaging, in general, and high speed imaging in particular are important emerging tools for the study of explosive volcanic eruptions. However, traditional 2-D video observations cannot measure volcanic ejecta motion toward and away from the camera, strongly hindering our capability to fully determine crucial hazard-related parameters such as explosion directionality and pyroclasts' absolute velocity. In this paper, we use up to three synchronized high-speed cameras to reconstruct pyroclasts trajectories in three dimensions. Classical stereographic techniques are adapted to overcome the difficult observation conditions of active volcanic vents, including the large number of overlapping pyroclasts which may change shape in flight, variable lighting and clouding conditions, and lack of direct access to the target. In particular, we use a laser rangefinder to measure the geometry of the filming setup and manually track pyroclasts on the videos. This method reduces uncertainties to 10° in azimuth and dip angle of the pyroclasts, and down to 20% in the absolute velocity estimation. We demonstrate the potential of this approach by three examples: the development of an explosion at Stromboli, a bubble burst at Halema'uma'u lava lake, and an in-flight collision between two bombs at Stromboli.

  14. Liquid carbon dioxide of magmatic origin and its role in volcanic eruptions

    USGS Publications Warehouse

    Chivas, A.R.; Barnes, I.; Evans, William C.; Lupton, J.E.; Stone, J.O.

    1987-01-01

    Natural liquid carbon dioxide is produced commercially from a 2.5-km-deep well near the 4,500-yr-old maar volcano, Mount Gambier, South Australia. The carbon dioxide has accumulated in a dome that is located on the extension of a linear chain of volcanic activity. A magmatic origin for the fluid is suggested by the geological setting, ??13CPDB of -4.0???, for the CO2 (where PDB represents the carbon-isotope standard), and a relatively high 3He component of the contained helium and high 3He/C ratio (6.4 x 10-10). The 3He/ 4He and He/Ne ratios are 3.0 and > 1,370 times those of air, respectively. The CO2, as collected at the Earth's surface at 29.5 ??C and 75 bar, expands more than 300-fold to form a gas at 1 atm and 22 ??C. We suggest that liquid CO2 or high-density CO2 fluid (the critical point is 31.1 ??C, 73.9 bar) of volcanic origin that expands explosively from shallow levels in the Earth's crust may be a major contributor to 'phreatic' volcanic eruptions and maar formation. Less violent release of magmatic CO2 into crater lakes may cause gas bursts with equally disastrous consequences such as occurred at Lake Nyos, Cameroon, in August 1986. ?? 1987 Nature Publishing Group.

  15. Simulation of the trans-oceanic tsunami propagation due to the 1883 Krakatau volcanic eruption

    NASA Astrophysics Data System (ADS)

    Choi, B. H.; Pelinovsky, E.; Kim, K. O.; Lee, J. S.

    The 1883 Krakatau volcanic eruption has generated a destructive tsunami higher than 40 m on the Indonesian coast where more than 36 000 lives were lost. Sea level oscillations related with this event have been reported on significant distances from the source in the Indian, Atlantic and Pacific Oceans. Evidence of many manifestations of the Krakatau tsunami was a subject of the intense discussion, and it was suggested that some of them are not related with the direct propagation of the tsunami waves from the Krakatau volcanic eruption. Present paper analyzes the hydrodynamic part of the Krakatau event in details. The worldwide propagation of the tsunami waves generated by the Krakatau volcanic eruption is studied numerically using two conventional models: ray tracing method and two-dimensional linear shallow-water model. The results of the numerical simulations are compared with available data of the tsunami registration.

  16. Early evolution of a stratospheric volcanic eruption cloud as observed with TOMS and AVHRR

    USGS Publications Warehouse

    Schneider, D.J.; Rose, William I.; Coke, L.R.; Bluth, G.J.S.; Sprod, I.E.; Krueger, A.J.

    1999-01-01

    This paper is a detailed study of remote sensing data from the total ozone mapping spectrometer (TOMS) and the advanced very high resolution radiometer (AVHRR) satellite detectors, of the 1982 eruption of El Chicho??n, Mexico. The volcanic cloud/atmosphere interactions in the first four days of this eruption were investigated by combining ultraviolet retrievals to estimate the mass of sulfur dioxide in the volcanic cloud [Krueger et al., 1995] with thermal infrared retrievals of the size, optical depth, and mass of fine-grained (1-10 ??m radius) volcanic ash [Wen and Rose, 1994]. Our study provides the first direct evidence of gravitational separation of ash from a stratospheric, gas-rich, plinian eruption column and documents the marked differences in residence times of volcanic ash and sulfur dioxide in volcanic clouds. The eruption column reached as high as 32 km [Carey and Sigurdsson, 1986] and was injected into an atmosphere with a strong wind shear, which allowed for an observation of the separation of sulfur dioxide and volcanic ash. The upper, more sulfur dioxide-rich part of the cloud was transported to the west in the stratosphere, while the fine-grained ash traveled to the south in the troposphere. The mass of sulfur dioxide released was estimated at 7.1 ?? 109 kg with the mass decreasing by approximately 4% 1 day after the peak. The mass of fine-grained volcanic ash detected was estimated at 6.5 ?? 109 kg, amounting to about 0.7% of the estimated mass of the ash which fell out in the mapped ash blanket close to the volcano. Over the following days, 98% of this remaining fine ash was removed from the volcanic cloud, and the effective radius of ash in the volcanic cloud decreased from about 8 ??m to about 4 ??m. Copyright 1999 by the American Geophysical Union.

  17. Measurement of post-eruptive volcanic deformation and depositional features using high-resolution remote sensing data

    NASA Astrophysics Data System (ADS)

    McAlpin, D. B.; Meyer, F. J.

    2011-12-01

    This proposal examines changes in volcanic geomorphology and topography using a new, multi-sensor approach to produce high-resolution digital elevation models (DEMs) and surface deformation maps that measure post-eruption volcanic changes and depositional features, including lava domes, lahars, and pyroclastic flow deposits. The advantage of this new approach is to exploit available data sets that have not previously been used systematically, or in full coordination. The use of readily available spaceborne remote sensing data is therefore maximized in a manner that is routine in method, but of sufficient quality to answer many important geophysical questions. Finally, this method provides these benefits while reducing expensive and potentially hazardous field campaigns. The multi-sensor approach involves a mix of stereoscopic optical, interferometric radar, and thermal space borne images to generate high-resolution DEMs and multi-sensor analyses of volcanic domes, as well as lower resolution analyses of deposits from other volcanic activity. The terrain of volcanic areas is subject to rapid topographic change. The time and elevation information obtained from DEMs of these areas enable us to perform accurate topographic phase correction of interferograms derived from interferometric synthetic aperture radar (InSAR) imaging and therefore facilitates the use of InSAR data for monitoring centimeter scale surface motion. It also allows us to determine quantitative volume estimates of dynamically emplaced deposits from lahars, tsunamis, and mud flows, and it provides information for emergency planners to use in risk assessments facing communities in volcanically active areas. A principal test scenario for our method is Redoubt Volcano in South-Central Alaska. During March and April, 2009, Redoubt erupted in a series of explosive eruptions that melted the Drift Glacier on its North flank, and produced lahars that inundated the adjacent Drift River Valley. Quantitative

  18. The Online GVP/USGS Weekly Volcanic Activity Report: Providing Timely Information About Worldwide Volcanism

    NASA Astrophysics Data System (ADS)

    Mayberry, G. C.; Guffanti, M. C.; Luhr, J. F.; Venzke, E. A.; Wunderman, R. L.

    2001-12-01

    The awesome power and intricate inner workings of volcanoes have made them a popular subject with scientists and the general public alike. About 1500 known volcanoes have been active on Earth during the Holocene, approximately 50 of which erupt per year. With so much activity occurring around the world, often in remote locations, it can be difficult to find up-to-date information about current volcanism from a reliable source. To satisfy the desire for timely volcano-related information the Smithsonian Institution and US Geological Survey combined their strengths to create the Weekly Volcanic Activity Report. The Smithsonian's Global Volcanism Program (GVP) has developed a network of correspondents while reporting worldwide volcanism for over 30 years in their monthly Bulletin of the Global Volcanism Network. The US Geological Survey's Volcano Hazards Program studies and monitors volcanoes in the United States and responds (upon invitation) to selected volcanic crises in other countries. The Weekly Volcanic Activity Report is one of the most popular sites on both organization's websites. The core of the Weekly Volcanic Activity Report is the brief summaries of current volcanic activity around the world. In addition to discussing various types of volcanism, the summaries also describe precursory activity (e.g. volcanic seismicity, deformation, and gas emissions), secondary activity (e.g. debris flows, mass wasting, and rockfalls), volcanic ash hazards to aviation, and preventative measures. The summaries are supplemented by links to definitions of technical terms found in the USGS photoglossary of volcano terms, links to information sources, and background information about reported volcanoes. The site also includes maps that highlight the location of reported volcanoes, an archive of weekly reports sorted by volcano and date, and links to commonly used acronyms. Since the Weekly Volcanic Activity Report's inception in November 2000, activity has been reported at

  19. Eruptive Productivity of the Ceboruco-San Pedro Volcanic Field, Nayarit, Mexico

    NASA Astrophysics Data System (ADS)

    Frey, H. M.; Lange, R. A.; Hall, C. M.; Delgado-Granados, H.

    2002-12-01

    High-precision 40Ar/39Ar geochronology coupled with GIS spatial analysis provides constraints on magma eruption rates over the past 1 Myr of the Ceboruco-San Pedro volcanic field (1870 km2), located in the Tepic-Zacoalco rift in western Mexico. The volcanic field is part of the Trans Mexican Volcanic arc and is dominated by the andesitic-dacitic stratocone of Volcan Ceboruco and includes peripheral fissure-fed flows, domes, and monogenetic cinder cones. The ages of these volcanic features were determined using 40Ar/39Ar laser step-heating techniques on groundmass or mineral separates, with 78% of the 52 analyses yielding plateau ages with a 2 sigma error < 50 kyrs. The volumes were determined using high resolution (1:50,000) digital elevation models, orthophotos, and GIS software, which allowed for the delineation of individual volcanic features, reconstruction of the pre-eruptive topography, and volume calculations by linear interpolation. The relative proportions of the 80 km3 erupted over the past 1 Myr are 14.5% basaltic andesite, 64.5% andesite, 20% dacite, and 1% rhyolite, demonstrating the dominance of intermediate magma types (in terms of silica content). Overall, there appears to be no systematic progression in the eruption of different magma types (e.g., basalt, andesite, dacite, etc.) with time. However, more than 75% of the total volume of lava within the Ceboruco-San Pedro volcanic field erupted in the last 100 kyrs. This reflects the youthfulness of Volcan Ceboruco, which was constructed during the last 50 kyrs and has a present day volume of 50 +/- 2.5 km3, accounting for 81% of the andesite and 50% of the dacite within the volcanic field. Eleven cinder cones, ranging from the Holocene to 0.37 Ma, display a narrow compositional range, with 52-58 wt% SiO2, 3-5.5 wt% MgO, and relatively high TiO2 concentrations (0.9-1.8 wt%). The total volume of the cinder cones is 0.83 km3. No lavas with < 51 wt% SiO2 have erupted in the past 1 Myr. Peripheral

  20. Dispersion of the volcanic sulfate cloud from a Mount Pinatubo-like eruption

    NASA Astrophysics Data System (ADS)

    Aquila, Valentina; Oman, Luke D.; Stolarski, Richard S.; Colarco, Peter R.; Newman, Paul A.

    2012-03-01

    We use the GEOS-5 general circulation model to simulate the transport of the volcanic cloud from an eruption similar to the 1991 eruption of Mount Pinatubo. The simulated aerosol optical thickness and transport of the volcanic cloud are in good agreement with observations of the actual Pinatubo eruption from the Stratospheric Aerosol and Gas Experiment II (SAGE II) and the Advanced Very High Resolution Radiometer (AVHRR) and with vertical profiles of sulfur dioxide observed by the Microwave Limb Sounder (MLS). We tested the importance of initial conditions corresponding to the specific meteorological situation at the time of the eruption by comparing results when GEOS-5 is initialized using Modern Era Retrospective Analyses for Research and Applications (MERRA) reanalysis fields with results when it is initialized from an existing model run. We found no significant difference in the transport of the cloud. We show how the inclusion of the interaction between volcanic sulfate aerosol and radiation is essential for a reliable simulation of the transport of the volcanic cloud. The absorption of longwave radiation by the volcanic sulfate largely induces the rising of the volcanic cloud up to the middle stratosphere and the divergent motion from the latitude of the eruption to the tropics. Our simulations indicate that the cloud is transported to the Northern Hemisphere through a lower stratospheric pathway and to middle and high latitudes of the Southern Hemisphere through a middle stratospheric pathway, centered at about 30 hPa. The direction of the middle stratospheric pathway depends on the season of the eruption.

  1. Nighttime Monitoring of Volcanic Eruptions with Satellite-Based Multispectral Infrared Radiometers

    NASA Astrophysics Data System (ADS)

    Zhizhin, M. N.; Trifonov, G.

    2015-12-01

    The Nightfire algorithm for detection of night-time infrared sources with multispectral radiometers from the Suomi NPP and Landsat 8 satellites can be used for global monitoring of volcanic activity. By searching the spatio-temporal database of the Nightfire detections in the vicinity of active volcanoes we can reconstruct the day-by-day history of recent eruptions, including the temperature and size of the lava flow. By correlation of the detections from different satellite zenith angles in some cases we can derive the 3D geometry of the lava lake. Potential application may be an early alert system to monitor remote volcanoes which are out of reach for permanent ground instrumentation network.

  2. Nightfire method to track volcanic eruptions from multispectral satellite images

    NASA Astrophysics Data System (ADS)

    Trifonov, Grigory; Zhizhin, Mikhail; Melnikov, Dmitry

    2016-04-01

    This work presents the first results of an application of the Nightfire hotspot algorithm towards volcano activity detection. Nightfire algorithm have been developed to play along with a Suomi-NPP polar satellite launched in 2011, which has a new generation multispectral VIIRS thermal sensor on board, to detect gas flares related to the upstream and downstream production of oil and natural gas. Simultaneously using of nighttime data in SWIR, MWIR, and LWIR sensor bands the algorithm is able to estimate the hotspot temperature, size and radiant heat. Four years of non-filtered observations have been accumulated in a spatio-temporal detection database, which currently totals 125 GB in size. The first part of this work presents results of retrospective cross-match of the detection database with the publicly available observed eruptions databases. The second part discusses how an approximate 3D shape of a lava lake could be modeled based on the apparent source size and satellite zenith angle. The third part presents the results of fusion Landsat-8 and Himawari-8 satellites data with the VIIRS Nightfire for several active volcanoes.

  3. Observations of a stratospheric aerosol veil from a tropical volcanic eruption in December 1808: is this the "Unknown" ~1809 eruption?

    NASA Astrophysics Data System (ADS)

    Guevara-Murua, A.; Williams, C. A.; Hendy, E. J.; Rust, A. C.; Cashman, K. V.

    2014-04-01

    The "Unknown" eruption of 1808/1809 was the second most explosive SO2-rich volcanic eruption in the last two centuries, only eclipsed by the cataclysmic VEI 7 Tambora eruption in April 1815. However, no eyewitness accounts of the event, and therefore its location, or the atmospheric optical effects associated with its aerosols have been documented from historical records. Here we report on two meteorological observations dating from the end of 1808 that describe phenomena we attribute to volcanic-induced atmospheric effects caused by the Unknown eruption. The observations were made by two highly respected Latin American scientists. The first, Francisco José de Caldas, describes a stratospheric aerosol haze, a "transparent cloud that obstructs the sun's brilliance", that was visible over the city of Bogotá, Colombia, from 11 December 1808 to at least mid-February 1809. The second, made by physician José Hipólito Unanue in Lima, Peru, describes sunset after-glows (akin to well-documented examples known to be caused by stratospheric volcanic aerosols) from mid-December 1808 to February 1809. These two accounts provide direct evidence of a persistent stratospheric aerosol veil that spanned at least 2600 km into both Northern and Southern Hemispheres and establish that the source was a tropical volcano. Moreover, these observations confirm that the Unknown eruption, previously identified and tentatively assigned to February 1809 (±4 months) from analysis of ice core sulphate records, occurred in late November or early December 1808 (4 December 1808 ± 7 days). This date has important implications for the associated hemispheric climate impacts and temporal pattern of aerosol dispersal.

  4. Pre-eruptive volatile and erupted gas phase characterization of the 2014 basalt of Bárðarbunga volcanic system, Iceland.

    NASA Astrophysics Data System (ADS)

    Haddadi, Baptiste; Moune, Séverine; Sigmarsson, Olgeir; Gauthier, Pierre-Jean; Gouhier, Mathieu

    2015-04-01

    -pack sampling of the gas plume was performed 2 October 2014 few hundred meters to the W of the active crater row. Filter packs were composed of three filters in series: one PTFE filter to collect particulate phases, followed by two impregnated filters to trap major gaseous species (SO2, HF and HCl). Sulphate (SO4) and halide (Cl- and F-) ion concentrations were determined by ion chromatography. The SO2/HCl molar ratio in the erupted gas phase at the eruption site is 29-46, only slightly higher than that estimated from the MIs. Trace element volatility and fluxes are discussed elsewhere (Gauthier et al., 2015) but the average SO2 flux calculated from lava volume estimate end of November as 1.2 km3 (Gouhier et al., 2015) is close to 1100 kg/sec. This is the highest SO2 flux ever estimated from gas plume measurements. References: Gauthier et al. (2015) Trace element degassing patterns and volcanic fluxes to the atmosphere during the 2014 Holuhraun eruption, Iceland. EGU General Assembly 2015. Gouhier et al. (2015) Retrieval of lava and SO2 long-lived emissions using MSG-SEVIRI data during the 2014 Holuhraun eruption. EGU General Assembly 2015.

  5. Measurement of post-eruptive deformation and depositional features from the 2009 Redoubt Volcanic Eruption using high-resolution digital elevation models

    NASA Astrophysics Data System (ADS)

    McAlpin, D. B.; Meyer, F.; Webley, P.

    2010-12-01

    We present a system to examine changes in volcanic morphology and topography using a new multi-sensor approach to produce high-resolution digital elevation models (DEMs), and measure post-eruption volcanic deformation and depositional features, including lava domes, lahars, and pyroclastic flow deposits. The developed system exploits available data sets that have not been previously subjected to systematic or fully coordinated use. By employing readily available space borne remote sensing data, resources are used in a manner that is routine in method, but of sufficient quality and availability to answer many important geophysical questions. The multi-sensor approach involves a mix of stereoscopic optical, interferometric radar, and thermal space borne imagery to generate DEMs and multi-sensor analyses of volcanic activity. Interferometric Synthetic Aperture Radar (InSAR) data originates from the European Remote Sensing (ERS)-2 / Envisat Advanced Synthetic Aperture Radar (ASAR) tandem campaign, whose setup allows DEM generation with sub-meter accuracy in flat to moderately hilly terrain. For areas not suitable for SAR analysis, accurate elevations are determined by photogrammetric analysis of high-resolution, stereoscopic optical data from the Japanese Aerospace Exploration Agency’s (JAXA’s) Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried by the Advanced Land-Observing Satellite (ALOS). The generated DEMs are associated with a time stamp and are stored in a database. The time annotation and elevation information of DEMs in volcanic areas that are subject to rapid and drastic topographic changes enable us to perform topographical correction of interferograms, with the appropriate elevation information. It also allows us to determine volume estimates of low-relief deposits such as lahars and other volcanic deposits along with their evolution over time. Higher relief features, such as volcanic domes, are similarly examined at a somewhat

  6. High-resolution sulfur isotopes in ice cores identify large stratospheric volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Burke, Andrea; Sigl, Michael; Adkins, Jess; Paris, Guillaume; McConnell, Joe

    2016-04-01

    The record of the volcanic forcing of climate over the past 2500 years is reconstructed primarily from sulfate concentrations in ice cores. Of particular interest are stratospheric eruptions, as these afford sulfate aerosols the longest residence time and largest dispersion in the atmosphere, and thus the greatest impact on radiative forcing. Identification of stratospheric eruptions currently relies on the successful matching of the same volcanic sulphate peak in ice cores from both the Northern and Southern hemispheres (a "bipolar event"). These are interpreted to reflect the global distribution of sulfur aerosols by the stratospheric winds. Despite its recent success, this method relies on precise and accurate dating of ice cores, in order to distinguish between a true 'bipolar event' and two separate eruptions that occurred in close temporal succession. Sulfur isotopes can been used to distinguish between these two scenarios since stratospheric sulfur aerosols are exposed to UV radiation which imparts a mass independent fractionation (Baroni et al., 2007). Mass independent fractionation of sulfate in ice cores thus offers a novel method of fingerprinting stratospheric eruptions, and thus refining the historic record of explosive volcanism and its forcing of climate. Here we present new high-resolution (sub-annual) sulfur isotope data from the Tunu Ice core in Greenland over seven eruptions. Sulfur isotopes were measured by MC-ICP-MS, which substantially reduces sample size requirements and allows high temporal resolution from a single ice core. We demonstrate the efficacy of the method on recent, well-known eruptions (including Pinatubo and Katmai/Novarupta), and then apply it to unidentified sulfate peaks, allowing us to identify new stratospheric eruptions. Baroni, M., Thiemens, M. H., Delmas, R. J., & Savarino, J. (2007). Mass-independent sulfur isotopic compositions in stratospheric volcanic eruptions. Science, 315(5808), 84-87. http://doi.org/10

  7. Magma, crust and water fluid. From the imbalance of their interaction to the modeling of volcanic eruption

    NASA Astrophysics Data System (ADS)

    Nechayev, A.

    2012-12-01

    The work describes a simple physical model that provides a theoretical justification for a single origin of the different types of volcanic eruptions. The leading mechanism of this model is that a vertical column of magma under certain conditions starts to be erupted by the critical action of water vapor fluid contained by the crust under high pressure and high temperature. This fundamental mechanism of imbalance between liquid and gas was first described as a mechanism of geyser eruption (Nechayev 2012a). A generalization of this mechanism in case of volcanic eruptions is developed in (Nechayev 2012b). We assume that the acceleration of magma and its eruption results from a pressure difference between magma and fluid in the contact zone at depths exceeding 1 km. Water vapor as a fluid can be found in the subduction zones where the oceanic crust with the sedimentary layer saturated by water is pushing under the continental crust delivering water fluid in the zone of active volcanism. Water vapor fluid in the supercritical state behaves as an ideal gas. The greater the volume of fluid the smaller the decrease of its pressure during the expansion. If the fluid penetrates the magma conduit and its volume exceeds a certain critical value, the fluid starts to push magma as a piston. The critical volume is equal to γSH, where γ is the adiabatic coefficient of water vapor (γ=1,4), S is the section of the magmatic conduit, H is the bedding depth of fluid layer. The greater the volume of superheated water fluid and the distance separating it from the magma chamber, the higher may be the eruption power. During volcanic eruption the fluid does work and expands, its pressure and density decrease, the eruption ends. To be repeated and to form a stratovolcano the eruption need some time to restore the critical volume of the fluid. This can occur due to the diffusion of fluid from the periphery. Perhaps it is just the fluid diffusion time which determines the interval between

  8. Geomorphic change along a gravel bed river affected by volcanic eruption: Rio Blanco - Volcan Chaiten (South Chile)

    NASA Astrophysics Data System (ADS)

    Picco, Lorenzo; Ravazzolo, Diego; Ulloa, Hector; Iroumé, Andres; Aristide Lenzi, Mario

    2014-05-01

    Gravel bed rivers are environments shaped by the balance of flow, sediment regimes, large wood (LW) and vegetation. Geomorphic changes are response to fluctuations and changes of runoff and sediment supply involving mutual interactions among these factors. Typically, many natural disasters (i.e. debris flows, floods and forest fires) can affect the river basin dynamics. Explosive volcanic eruptions present, instead, the potential of exerting severe impacts as, for example, filling river valleys or changing river network patterns thanks to massive deposition of tephra and volcanic sediment all over the main channel and over the basin. These consistent impacts can strongly affect both hydrology and sediment transport dynamics, all over the river system, producing huge geomorphic changes. During the last years there has been a consistent increase in the survey technologies that permit to monitor geomorphic changes and to estimate sediment budgets through repeat topographic surveys. The calculation of differences between subsequent DEMs (difference of DEMs, DoD) is a commonly applied method to analyze and quantify these dynamics. Typically the higher uncertainty values are registered in areas with higher topographic variability and lower point density. This research was conducted along a ~ 2.2 km-long sub-reach of the Blanco River (Southern Chile), a fourth-order stream that presents a mainly rainfall regime with winter peak flows. The May 2008 Chaitén volcanic eruption strongly affected the entire Rio Blanco basin. The entire valley was highly exposed to the pyroclastic and fluvial flows, which affected directly a consistent area of evergreen forests. Extreme runoff from the upper Blanco catchment aggraded the channel and deposited up to several meters of tephra, alluvium, and LW along the entire river system. Aims of this contribution are to define and quantify the short term evolution of the Blanco River after the big eruption event and a subsequent consistent

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

    NASA Astrophysics Data System (ADS)

    Jouannic, G.; Walter-Simonnet, A. V.; Bossuet, G.; Cubizolle, H.; Boivin, P.; Devidal, J. L.; Oberlin, C.

    2014-08-01

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

  10. Risk assessment of the impact of future volcanic eruptions on direct normal irradiance

    NASA Astrophysics Data System (ADS)

    Pagh Nielsen, Kristian; Blanc, Philippe; Vignola, Frank

    2016-04-01

    Stratospheric sulfate aerosols from Plinian volcanic eruptions affect the solar surface irradiance forcing by scattering the solar radiation as it passes through the Earth atmosphere. Since these aerosols have high single scattering albedos they mostly affect direct normal irradiances (DNI). The effect on global horizontal irradiance (GHI) is less because some of the scattered irradiance reaches the surface as diffuse horizontal irradiance (DHI) and adds to the GHI. DNI is the essential input to concentrating solar thermal electric power (CSP/STE) and concentrated photovoltaic (CPV) plants. Therefore, an assessment of the future potential variability in the DNI resource caused by Plinian volcanic eruptions is desirable. Based on investigations of the El Chichón and Pinatubo eruptions, the microphysical, and thereby optical, properties of the stratospheric sulfate aerosols are well known. Given these, radiative transfer computations of the DNI resource can be made. The DNI resource includes forward scattered irradiance within the acceptance angle of a given CSP/STE or CPV plant. The rarity of Plinian eruptions poses a challenge for assessing the statistical risk of future eruptions and its potential of risk in the electricity production. Here we present and discuss methods to account for these potential volcanic eruptions for technical and economical studies including scenarios with very high probability of exceedance (e.g. P99 scenarios) for risk assessment of DNI-based solar power projects.

  11. Water vapour variability in the high-latitude upper troposphere - Part 2: Impact of volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Sioris, Christopher E.; Zou, Jason; McElroy, C. Thomas; Boone, Chris D.; Sheese, Patrick E.; Bernath, Peter F.

    2016-02-01

    The impact of volcanic eruptions on water vapour in the high-latitude upper troposphere is studied using deseasonalized time series based on observations by the Atmospheric Chemistry Experiment (ACE) water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) and the Fourier Transform Spectrometer (ACE-FTS). The two eruptions with the greatest impact on the high-latitude upper troposphere during the time frame of this satellite-based remote sensing mission are chosen. The Puyehue-Cordón Caulle volcanic eruption in June 2011 was the most explosive in the past 24 years and is shown to be able to account for the observed (50 ± 12) % increase in water vapour in the southern high-latitude upper troposphere in July 2011 after a minor adjustment for the simultaneous influence of the Antarctic oscillation. Eyjafjallajökull erupted in the spring of 2010, increasing water vapour in the upper troposphere at northern high latitudes significantly for a period of ˜ 1 month. These findings imply that extratropical volcanic eruptions in windy environments can lead to significant perturbations to high-latitude upper tropospheric humidity mostly due to entrainment of lower tropospheric moisture by wind-blown plumes. The Puyehue-Cordón Caulle eruption must be taken into account to properly determine the magnitude of the trend in southern high-latitude upper tropospheric water vapour over the last decade.

  12. Timing and climate forcing of volcanic eruptions for the past 2,500 years.

    PubMed

    Sigl, M; Winstrup, M; McConnell, J R; Welten, K C; Plunkett, G; Ludlow, F; Büntgen, U; Caffee, M; Chellman, N; Dahl-Jensen, D; Fischer, H; Kipfstuhl, S; Kostick, C; Maselli, O J; Mekhaldi, F; Mulvaney, R; Muscheler, R; Pasteris, D R; Pilcher, J R; Salzer, M; Schüpbach, S; Steffensen, J P; Vinther, B M; Woodruff, T E

    2015-07-30

    Volcanic eruptions contribute to climate variability, but quantifying these contributions has been limited by inconsistencies in the timing of atmospheric volcanic aerosol loading determined from ice cores and subsequent cooling from climate proxies such as tree rings. Here we resolve these inconsistencies and show that large eruptions in the tropics and high latitudes were primary drivers of interannual-to-decadal temperature variability in the Northern Hemisphere during the past 2,500 years. Our results are based on new records of atmospheric aerosol loading developed from high-resolution, multi-parameter measurements from an array of Greenland and Antarctic ice cores as well as distinctive age markers to constrain chronologies. Overall, cooling was proportional to the magnitude of volcanic forcing and persisted for up to ten years after some of the largest eruptive episodes. Our revised timescale more firmly implicates volcanic eruptions as catalysts in the major sixth-century pandemics, famines, and socioeconomic disruptions in Eurasia and Mesoamerica while allowing multi-millennium quantification of climate response to volcanic forcing.

  13. Determination of volumetric variations and coastal changes due to historical volcanic eruptions using historical maps and remote-sensing at Deception Island (West-Antarctica)

    NASA Astrophysics Data System (ADS)

    Torrecillas, C.; Berrocoso, M.; Pérez-López, R.; Torrecillas, M. D.

    2012-01-01

    Deception Island is an active volcano in the South Shetland Islands (Antarctic). Its eruptions have been recorded since 1842, the last episode occurring between 1967 and 1970. This study quantifies the geomorphological changes which have taken place as a result of historical volcanic activity on the island. The linear and volumetric results obtained for the Telefon Bay and Craters of 1970s where the Surtseyan eruption took place in 1967 are presented in detail.

  14. Parameters influencing the location and characteristics of volcanic eruptions in a youthful extensional setting: Insights from the Virunga Volcanic Province, in the Western Branch of the East African Rift System

    NASA Astrophysics Data System (ADS)

    Smets, Benoît; d'Oreye, Nicolas; Kervyn, Matthieu; Kervyn, François

    2016-04-01

    The East African Rift System (EARS) is often mentioned as the modern archetype for rifting and continental break-up (Calais et al., 2006, GSL Special Publication 259), showing the complex interaction between rift faults, magmatism and pre-existing structures of the basement. Volcanism in the EARS is characterized by very active volcanoes, several of them being among the most active on Earth (Wright et al., 2015, GRL 42). Such intense volcanic activity provides useful information to study the relationship between rifting, magmatism and volcanism. This is the case of the Virunga Volcanic Province (VVP) located in the central part of the Western Branch of the EARS, which hosts two of the most active African volcanoes, namely Nyiragongo and Nyamulagira. Despite the intense eruptive activity in the VVP, the spatial distribution of volcanism and its relationship with the extensional setting remain little known. Here we present a study of the interaction between tectonics, magmatism and volcanism at the scale of the Kivu rift section, where the VVP is located, and at the scale of a volcano, by studying the dense historical eruptive activity of Nyamulagira. Both the complex Precambrian basement and magmatism appear to contribute to the development of the Kivu rift. The presence of transfer zones north and south of the Lake Kivu rift basin favoured the development of volcanic provinces at these locations. Rift faults, including reactivated Precambrian structures influenced the location of volcanism within the volcanic provinces and the rift basin. At a more local scale, the historical eruptive activity of Nyamulagira highlights that, once a composite volcano developed, the gravitational stress field induced by edifice loading becomes the main parameter that influence the location, duration and lava volume of eruptions.

  15. Volcanic eruptions: Atmospheric effects. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-02-01

    The bibliography contains citations concerning gaseous and particulate contributions to the Earth's atmosphere from volcanoes, and the effects these substances have on the climate and the environment. Citations cover case studies of specific volcanic eruptions, detection and measurement of volcanic gases and aerosols in the atmosphere, environmental effects on the biota, long and short term climatological effects, paleoclimatology and volcanoes, atmospheric and transport modeling, and solar radiation inhibition. (Contains a minimum of 214 citations and includes a subject term index and title list.)

  16. Chemical composition of volcanic gases emitted during the 2014-15 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Hernández, Pedro A.; Melián, Gladys V.; Dionis, Samara; Barrancos, José; Padilla, Germán; Padrón, Eleazar; Silva, Sónia; Fernandes, Paulo; Cardoso, Nadir; Pérez, Nemesio M.; Rodríguez, Fátima; Asensio-Ramos, María; Calvo, David; Semedo, Helio; Alfama, Vera

    2015-04-01

    Pico do Fogo volcano (2,800 m) is the youngest and most active volcano of the Cape Verde archipelago and is located in Fogo Island. In November 23, 2014, a new volcanic eruption occurred at the west flank of Pico do Fogo, near the site of the 1995 eruption. From November 28, 2014, daily SO2 ground-based plume measurements have been performed by ITER/INVOLCAN/UNICV/OVCV/SNPC research team, representing the first SO2 plume measurements ever performed during an eruption of this volcano. Measurements were carried out with a miniature ultraviolet (UV) spectrometer miniDOAS to estimate the SO2 emission from the volcanic plume. On November 30th by combining mini-DOAS and a portable multi-sensor gas (Shinohara et al., 2005), we were able to quantify the SO2, H2S, H2, CO2 and H2O emission rates from the plume. Multi-sensor gas measurements were performed about 1 km distance from the eruptive vent. Average SO2 emission rate calculated from 4 traverses on November 30, 2014, was 117 kg s-1 (10,118 t d-1). Combining this value with the estimated average CO2/SO2, SO2/H2S, and H2S/H2 and H2O/SO2 mass ratios (1.06, 178, 568 and 2.40, respectively), we calculated the CO2, H2S, H2 and H2O plume emissions: 124 kg s-1 (10,688 t d-1), 0.7 kg s-1 (57 t d-1), 0.2 kg s-1 (18 t d-1), and 281 kg s-1 (24,245 t d-1), respectively. Plume gas composition obtained in November 30 indicated average CO2/SO2, CO2/H2O and SO2/H2S molar ratios of 1.5, 0.3 and 7.5, respectively. These values were remarkably different from those molar ratios measured at the fumarole discharges from summit crater previously to the eruption onset, and representative of the ascent of magma to the surface and the injection of SO2-rich hot magmatic gases in the H2S-rich hydrothermal system of Pico do Fogo volcano as was observed through the increase on the SO2/ H2S and decrease on the CO2/SO2 measured molar plume ratios. Based on the measured chemical composition of the plume, the apparent equilibrium temperature (AET) was

  17. Detection and estimation of volcanic eruption onset and mass flow rate using weather radar and infrasonic array

    NASA Astrophysics Data System (ADS)

    Marzano, Frank S.; Mereu, Luigi; Montopoli, Mario; Picciotti, Errico; Di Fabio, Saverio; Bonadonna, Costanza; Marchetti, Emanuele; Ripepe, Maurizio

    2015-04-01

    The explosive eruption of sub-glacial Eyjafjallajökull volcano in 2010 was of modest size, but ash was widely dispersed over Iceland and Europe. The Eyjafjallajökull pulsating explosive activity started on April 14 and ended on May 22. The combination of a prolonged and sustained ejection of volcanic ash and persistent northwesterly winds resulted in dispersal the volcanic cloud over a large part of Europe. Tephra dispersal from an explosive eruption is a function of multiple factors, including magma mass flow rate (MFR), degree of magma fragmentation, vent geometry, plume height, particle size distribution (PSD) and wind velocity. One of the most important geophysical parameters, derivable from the analysis of tephra deposits, is the erupted mass, which is essential for the source characterization and assessment of the associated hazards. MFR can then be derived by dividing the erupted mass by the eruption duration (if known) or based on empirical and analytical relations with plume height. Microwave weather radars at C and X band can provide plume height, ash concentration and loading, and, to some extent, PSD and MFR. Radar technology is well established and can nowadays provide fast three-dimensional (3D) scanning antennas together with Doppler and dual polarization capabilities. However, some factors can limit the detection and the accuracy of the radar products aforementioned. For example, the sensitivity of microwave radar measurements depends on the distance between the radar antenna and the target, the transmitter central wavelength, receiver minimum detachable power and the resolution volume. In addition, radar measurements are sensitive to particle sizes larger than few tens of microns thus limiting the radar-based quantitative estimates to the larger portion of the PSD. Volcanic activity produces infrasonic waves (i.e., acoustic waves below 20 Hz), which can propagate in the atmosphere useful for the remote monitoring of volcanic activity. Infrasound

  18. Direct injection of water vapor into the stratosphere by volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Sioris, Christopher E.; Malo, Alain; McLinden, Chris A.; D'Amours, Real

    2016-07-01

    While theoretical studies show that water vapor (WV) can be directly injected into the stratosphere during a volcanic eruption, few observations of such a phenomenon exist. The Microwave Limb Sounder observed stratospheric injection of WV following the 2015 Calbuco eruption. Lower stratospheric mixing ratios exceeded 10 ppmv for a few days downwind of the injection location. Plume transport is confirmed by back trajectory modeling. Due to the short duration and limited spatial extent of the enhancement, climatic impact is expected to be negligible. This letter provides spatiotemporal analysis of a volcanogenic pulse of lower stratospheric WV as it dispersed. The inferred mass of stratospheric WV from this eruption of 2 megaton (Mt) and the rapid evanescence of the enhancement are similar to what has been observed for other eruptions, suggesting that injection by moderately explosive eruptions is not an effective mechanism for large-scale stratospheric hydration.

  19. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Fuglestvedt, Jan S.; Samset, Bjørn H.; Shine, Keith P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. We show, for the first time, that it may be possible to counteract these climate effects through deliberate emissions of short-lived greenhouse gases, dampening the abrupt impact of an eruption. We estimate an emission pathway countering a hypothetical eruption 3 times the size of Mount Pinatubo in 1991. We use a global climate model to evaluate global and regional responses to the eruption, with and without counteremissions. We then raise practical, financial, and ethical questions related to such a strategy. Unlike the more commonly discussed geoengineering to mitigate warming from long-lived greenhouse gases, designed emissions to counter temporary cooling would not have the disadvantage of needing to be sustained over long periods. Nevertheless, implementation would still face significant challenges.

  20. ENSO response to high-latitude volcanic eruptions: the role of the initial conditions

    NASA Astrophysics Data System (ADS)

    Pausata, Francesco S. R.; Caballero, Rodrigo; Battisti, David S.

    2016-04-01

    Large volcanic eruptions can have major impacts on global climate affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is around 2-3 years and attention has consequently focused on their short-term impacts, and in particular on tropical eruptions. The long-term, ocean-mediated response has been less studied and large uncertainties remain. Moreover, studies have largely focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts have been thought to be merely hemispheric rather than global and no study has hitherto investigated the long-term effects of such eruptions. Here we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere could cause an El Niño-like anomaly in the equatorial Pacific during the first 8-9 months after the start of the eruption owing to a strong hemispheric cooling. The hemispherically asymmetric cooling shifts the Inter-Tropical Convergence Zone southwards, triggering a weakening of the trade winds over the western and central equatorial Pacific that leads to an El Niño-like anomaly. However, the El Niño-like anomaly strongly depends on the initial ENSO state: a 3-time larger response is shown when the climate system is going towards a La Niña compared to when is going towards an El Niño. Finally, the eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first twenty-five years after the eruption, followed by a weakening lasting at least 35 years. The long-lived changes in the AMOC strength also alter the variability of El Niño-Southern Oscillation.

  1. Long-term eruptive activity at a submarine arc volcano.

    PubMed

    Embley, Robert W; Chadwick, William W; Baker, Edward T; Butterfield, David A; Resing, Joseph A; de Ronde, Cornel E J; Tunnicliffe, Verena; Lupton, John E; Juniper, S Kim; Rubin, Kenneth H; Stern, Robert J; Lebon, Geoffrey T; Nakamura, Ko-ichi; Merle, Susan G; Hein, James R; Wiens, Douglas A; Tamura, Yoshihiko

    2006-05-25

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. PMID:16724063

  2. Long-term eruptive activity at a submarine arc volcano

    USGS Publications Warehouse

    Embley, R.W.; Chadwick, W.W.; Baker, E.T.; Butterfield, D.A.; Resing, J.A.; De Ronde, C. E. J.; Tunnicliffe, V.; Lupton, J.E.; Juniper, S.K.; Rubin, K.H.; Stern, R.J.; Lebon, G.T.; Nakamura, K.-I.; Merle, S.G.; Hein, J.R.; Wiens, D.A.; Tamura, Y.

    2006-01-01

    Three-quarters of the Earth's volcanic activity is submarine, located mostly along the mid-ocean ridges, with the remainder along intraoceanic arcs and hotspots at depths varying from greater than 4,000 m to near the sea surface. Most observations and sampling of submarine eruptions have been indirect, made from surface vessels or made after the fact. We describe here direct observations and sampling of an eruption at a submarine arc volcano named NW Rota-1, located 60 km northwest of the island of Rota (Commonwealth of the Northern Mariana Islands). We observed a pulsating plume permeated with droplets of molten sulphur disgorging volcanic ash and lapilli from a 15-m diameter pit in March 2004 and again in October 2005 near the summit of the volcano at a water depth of 555 m (depth in 2004). A turbid layer found on the flanks of the volcano (in 2004) at depths from 700 m to more than 1,400 m was probably formed by mass-wasting events related to the eruption. Long-term eruptive activity has produced an unusual chemical environment and a very unstable benthic habitat exploited by only a few mobile decapod species. Such conditions are perhaps distinctive of active arc and hotspot volcanoes. ?? 2006 Nature Publishing Group.

  3. Effects of Mount Pinatubo Volcanic Eruption on the Hydrological Cycle as an Analog of Geoengineering

    NASA Astrophysics Data System (ADS)

    Trenberth, K. E.

    2007-05-01

    Much of my work in recent years has been devoted to understanding the hydrological and energy cycles. The incoming radiant energy from the sun is transformed into various forms (internal heat, potential energy, latent energy, and kinetic energy) moved around in various ways primarily by the atmosphere and oceans, stored and sequestered in the ocean, land, and ice components of the climate system, and ultimately radiated back to space as infrared radiation. The requirement for an equilibrium climate mandates a balance between the incoming and outgoing radiation and further mandates that the flows of energy are systematic. The imbalance at top of atmosphere from increasing greenhouse gases from human activities creates warming. The central concern with geoengineering fixes to global warming is that the cure could be worse than the disease. The problem of global warming arises from the buildup of greenhouse gases such as carbon dioxide from burning of fossil fuels and other human activities that change the composition of the atmosphere. However, the solution proposed is to reduce the incoming sunshine by emulating a volcanic eruption. In between the incoming solar radiation and the outgoing longwave radiation is the entire weather and climate system and the operation of the hydrological cycle. The eruption of Mount Pinatubo in 1991 is used as an analog for the geoengineering and show that there was a substantial decrease in precipitation over land and a record decrease in runoff and streamflow in 1992, suggesting that major adverse effects, such as drought, could arise from such geoengineering solutions.

  4. Volcanic activity at Tvashtar Catena, Io

    USGS Publications Warehouse

    Milazzo, M.P.; Keszthelyi, L.P.; Radebaugh, J.; Davies, A.G.; Turtle, E.P.; Geissler, P.; Klaasen, K.P.; Rathbun, J.A.; McEwen, A.S.

    2005-01-01

    Galileo's Solid State Imager (SSI) observed Tvashtar Catena four times between November 1999 and October 2001, providing a unique look at a distinctive high latitude volcanic complex on Io. The first observation (orbit I25, November 1999) resolved, for the first time, an active extraterrestrial fissure eruption; the brightness temperature was at least 1300 K. The second observation (orbit I27, February 2000) showed a large (??? 500 km 2) region with many, small, hot, regions of active lava. The third observation was taken in conjunction with Cassini imaging in December 2000 and showed a Pele-like, annular plume deposit. The Cassini images revealed an ???400 km high Pele-type plume above Tvashtar Catena. The final Galileo SSI observation of Tvashtar (orbit I32, October 2001), revealed that obvious (to SSI) activity had ceased, although data from Galileo's Near Infrared Mapping Spectrometer (NIMS) indicated that there was still significant thermal emission from the Tvashtar region. In this paper, we primarily analyze the style of eruption during orbit I27 (February 2000). Comparison with a lava flow cooling model indicates that the behavior of the Tvashtar eruption during I27 does not match that of simple advancing lava flows. Instead, it may be an active lava lake or a complex set of lava flows with episodic, overlapping eruptions. The highest reliable color temperature is ???1300 K. Although higher temperatures cannot be ruled out, they do not need to be invoked to fit the observed data. The total power output from the active lavas in February 2000 was at least 1011 W. ?? 2005 Elsevier Inc. All rights reserved.

  5. Stratospheric chlorine injection by volcanic eruptions - HCl scavenging and implications for ozone

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Turco, R. P.

    1993-01-01

    Because the output of volatile chlorine during a major volcanic event can greatly exceed the annual anthropogenic emissions of chlorine to the atmosphere, the fate of volcanic chlorine must be known. Although numerous observations have shown that volcanoes do not significantly contribute to the stratospheric chlorine burden, no quantitative explanation has been published. Hydrogen chloride (HCl) scavenging processes during the early phases of a volcanic eruption are discussed. A plume dynamics and thermodynamics model is used to show that HCl removal in condensed supercooled water can reduce HCl vapor concentrations by up to four orders of magnitude, preventing substantial stratospheric chlorine injection.

  6. Hydrothermal reservoir beneath Taal Volcano (Philippines): Implications to volcanic activity

    NASA Astrophysics Data System (ADS)

    Nagao, T.; Alanis, P. B.; Yamaya, Y.; Takeuchi, A.; Bornas, M. V.; Cordon, J. M.; Puertollano, J.; Clarito, C. J.; Hashimoto, T.; Mogi, T.; Sasai, Y.

    2012-12-01

    Taal Volcano is one of the most active volcanoes in the Philippines. The first recorded eruption was in 1573. Since then it has erupted 33 times resulting in thousands of casualties and large damages to property. In 1995, it was declared as one of the 15 Decade Volcanoes. Beginning in the early 1990s it has experienced several phases of abnormal activity, including seismic swarms, episodes of ground deformation, ground fissuring and hydrothermal activities, which continues up to the present. However, it has been noted that past historical eruptions of Taal Volcano may be divided into 2 distinct cycles, depending on the location of the eruption center, either at Main Crater or at the flanks. Between 1572-1645, eruptions occurred at the Main Crater, in 1707 to 1731, they occurred at the flanks. In 1749, eruptions moved back to the Main Crater until 1911. During the 1965 and until the end of the 1977 eruptions, eruptive activity once again shifted to the flanks. As part of the PHIVOLCS-JICA-SATREPS Project magnetotelluric and audio-magnetotelluric surveys were conducted on Volcano Island in March 2011 and March 2012. Two-dimensional (2-D) inversion and 3-D forward modeling reveals a prominent and large zone of relatively high resistivity between 1 to 4 kilometers beneath the volcano almost directly beneath the Main Crater, surrounded by zones of relatively low resistivity. This anomalous zone of high resistivity is hypothesized to be a large hydrothermal reservoir filled with volcanic fluids. The presence of this large hydrothermal reservoir could be related to past activities of Taal Volcano. In particular we believe that the catastrophic explosion described during the 1911 eruption was the result of the hydrothermal reservoir collapsing. During the cycle of Main Crater eruptions, this hydrothermal reservoir is depleted, while during a cycle of flank eruptions this reservoir is replenished with hydrothermal fluids.

  7. 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

  8. The radiative impact of major volcanic eruptions on stratospheric water vapour

    NASA Astrophysics Data System (ADS)

    Löffler, Michael; Brinkop, Sabine; Jöckel, Patrick

    2016-04-01

    Volcanic eruptions can have significant impact on the earth's weather and climate system. Besides the subsequent tropospheric changes also the stratosphere is influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour after the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as important sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on the tropospheric water vapour and ENSO are evident.

  9. Pre-eruptive storage conditions and eruption dynamics of a small rhyolite dome: Douglas Knob, Yellowstone volcanic field, USA

    NASA Astrophysics Data System (ADS)

    Befus, Kenneth S.; Zinke, Robert W.; Jordan, Jacob S.; Manga, Michael; Gardner, James E.

    2014-03-01

    The properties and processes that control the size, duration, and style of eruption of rhyolite magma are poorly constrained because of a paucity of direct observations. Here, we investigate the small-volume, nonexplosive end-member. In particular, we determine the pre-eruptive storage conditions and eruption dynamics of Douglas Knob, a 0.011-km3 obsidian dome that erupted from a 500-m-long fissure in the Yellowstone volcanic system. To determine pre-eruptive storage conditions, we analyzed compositions of phenocrysts, matrix glass, and quartz-hosted glass inclusions by electron microprobe and Fourier-transform infrared analyses. The pre-eruptive melt is a high-silica rhyolite (˜75 wt.% SiO2) and was stored at 760 ± 30 °C and 50 ± 25 MPa prior to eruption, assuming vapor saturation at depth. To investigate emplacement dynamics and kinematics, we measured number densities and orientations of microlites at various locations across the lava dome. Microlites in samples closest to the inferred fissure vent are the most aligned. Alignment does not increase with distance traveled away from the vent, suggesting microlites record conduit processes. Strains of <5 accumulated in the conduit during ascent after microlite formation, imparted by a combination of pure and simple shear. Average microlite number density in samples varies from 104.9 to 105.7 mm-3. Using the magma ascent model of Toramaru et al. (J Volcanol Geotherm Res 175:156-157, 2008), microlite number densities imply decompression rates ranging from 0.03 to 0.11 MPa h-1 (˜0.4-1.3 mm s-1 ascent rates). Such slow ascent would allow time for passive degassing at depth in the conduit, thus resulting in an effusive eruption. Using calculated melt viscosity, we infer that the dike that fed the eruption was 4-8 m in width. Magma flux through this dike, assuming fissure dimensions at the surface represent its geometry at depth, implies an eruption duration of 17-210 days. That duration is also consistent with the

  10. Volcanic origin of the eruptive plumes on Io

    USGS Publications Warehouse

    Cook, A.F.; Shoemaker, E.M.; Smith, B.A.; Danielson, G.E.; Johnson, T.V.; Synnott, S.P.

    1981-01-01

    A quadruple long exposure of Io in eclipse exhibits faint auroral emission from the eruptive plumes. No luminous spots in the vents, predicted by Gold, were observed. Heat from the interior of Io appears to be the predominant source of energy in the plumes. Copyright ?? 1981 AAAS.

  11. Enhancements in biologically effective ultraviolet radiation following volcanic eruptions

    NASA Technical Reports Server (NTRS)

    Vogelmann, A. M.; Ackerman, T. P.; Turco, R. P.

    1992-01-01

    A radiative transfer model is used to estimate the changes in biologically effective radiation (UV-BE) at the earth's surface produced by the El Chichon (1982) and Mount Pinatubo (1991) eruptions. It is found that in both cases surface intensity can increase because the effect of ozone depletion outweighs the increased scattering.

  12. Preliminary Results on the 2015 Eruption of Wolf Volcano, Isabela Island, Galápagos: Chronology, Dispersion of the Volcanic Products, and Insight into the Eruptive Dynamics

    NASA Astrophysics Data System (ADS)

    Wright, H. M. N.; Bernard, B.; Ramon, P.; Guevara, A.; Hidalgo, S.; Pacheco, D. A.; Narváez, D.; Vásconez, F.

    2015-12-01

    After 33 years of quiescence, Wolf volcano, located in the northernmost tip of Isabela Island (Galápagos Islands, Ecuador), started a new eruption on May 25, 2015. The first signs of activity were recorded at 5:50 UTC (23:50 on May 24, Local Time in Galápagos) by a seismic station installed on Fernandina island. The first visual observation was reported at 7:38 UTC (1:38 LT). Based on amateur film footage, the vent was a >800 m-long circumferential fissure that produced a >100 m-high lava curtain. The eruption also released a 15 km-high gas plume with a large amount of SO2 and minimal ash content. Lightning was observed in the plume but not near the vent. Due to complex wind directions at high altitude, the gas cloud drifted in all directions eventually coming toward the continent and producing an extremely small ashfall in Quito that was detected only through the use of homemade ashmeters. The ash sample included lava droplets, scoria, and one small fragment of reticulite, indicating high lava fountaining during the first days of the eruption. The active vents on the circumferential fissure, initially located on the SE side of the caldera outer rim, moved progressively northward, eventually extending for a total of 2 km. One week later on June 02, satellite imagery (OMI, GOME, MODIS) documented decreased volcanic activity, leaving two new lava fields covering over 17 km2 on the SE (10 km-long and up to 2 km-wide) and E (7 km-long and up to 1 km-wide, reaching the sea) flanks of the volcano. Volcanic activity resumed on June 11, and on June 13 it shifted into the caldera, apparently emerging from a fissure close to the vent from the 1982 eruption, about 4 km W of the circumferential fissure. This new lava flow covered approximately 3.5 km2 of the caldera floor. Finally, volcanic activity waned at the end of June and appeared to have ended by July 11, accounting for one of the largest eruptions in the Galápagos since 1968 based on remote sensing.

  13. Communicating Uncertainty to the Public During Volcanic Unrest and Eruption -A Case Study From the 2004-2005 Eruption of Mount St. Helens, USA

    NASA Astrophysics Data System (ADS)

    Gardner, C. A.; Pallister, J. S.

    2005-12-01

    worldwide web, teleconferences, and meetings with land and emergency managers. Initial concerns revolved around the questions of if and when an eruption would occur, whether it would be explosive, and how large-all questions without definitive answers. As the eruption progresses, concerns have transformed to whether the eruptive behavior will change and how long the eruption will last-also questions lacking definitive answers. We have found it important in communicating our uncertainty to the public to articulate how we came to our conclusions and why our answers cannot be more definitive. We have also found that framing volcanic uncertainty in terms of more common analogies (e.g. knowing that conditions are right for development of a tornado, but not being able to predict exactly when a funnel cloud will form, precisely where it will touch down, or how severe the damage will be) appears to help the public and public officials understand volcanic uncertainty better. As the eruption continues and people become more accustomed to the activity, we find an increasingly more knowledgeable public who can better understand and deal with uncertainty. Also, it is clear that establishing interagency relationships by developing volcano response plans before a crisis greatly facilitates a successful response. A critical component of this planning is discussing uncertainties inherent during volcanic crises such that when unrest begins, the concept of, and reasons behind uncertainty are already well understood.

  14. 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

  15. Contrastive research of ionospheric precursor anomalies between Calbuco volcanic eruption on April 23 and Nepal earthquake on April 25, 2015

    NASA Astrophysics Data System (ADS)

    Li, Wang; Guo, Jinyun; Yue, Jianping; Yang, Yang; Li, Zhen; Lu, Deikai

    2016-05-01

    On April 23, 2015, the VEI4 (volcanic explosive index) Calbuco volcano abruptly erupted in Chile and the Mw7.9 Nepal earthquake occurred on April 25. In order to investigate the similarities and differences between total electron content (TEC) anomalies preceding these two types of geophysical activities, the TEC time series over preparation zones before the volcanic eruption and earthquake extracted from global ionosphere map were analyzed. We used sunspot numbers (SSN), Bz, Dst, and Kp indices to represent the solar-terrestrial environment and eliminate the effects of solar and geomagnetic activities on ionosphere by the sliding interquartile range method with the 27-day window. The results indicate that TEC-negative and -positive anomalies appeared in the 14th and 6th day before the eruption, respectively. The anomalies lasted about 4-6 h with a magnitude of 15-20 TECU. The TEC anomalies were also observed on the 14th and 6th day before the Nepal earthquake with a duration of 6-8 h, and the absolute magnitude of TEC anomalies was within 12-20 TECU. These findings indicate that the magnitude of TEC anomalies preceding volcanic eruption was larger, and the duration of TEC anomalies before the earthquake was longer, which may be associated with their particular physical mechanisms. The TEC anomalies before the Nepal earthquake in the Eastern hemisphere occurred in the afternoon local time, but those before the eruption were observed in the night local time. Peak regions of TEC anomalies did not coincide with the epicenters of geophysical activities, and the TEC anomalies also appeared in the magnetic conjugated region. Both the TEC anomalies in the preparation zone and conjugated region were distributed near the boundaries of equatorial anomaly zone and moved along the boundaries. In the moving process, sometimes the extent or magnitude of TEC anomalies in the conjugated region was larger than that in the preparation zone. Many more GPS stations and receivers

  16. The nearshore benthic community of Kasatochi Island, one year after the 2008 volcanic eruption

    USGS Publications Warehouse

    Jewett, S.C.; Bodkin, J.L.; Chenelot, H.; Esslinger, G.G.; Hoberg, M.K.

    2010-01-01

    A description is presented of the nearshore benthic community of Kasatochi Island 1012 months after a catastrophic volcanic eruption in 2008. The eruption extended the coastline of the island approximately 400 m offshore, mainly along the south, southeast, and southwest shores, to roughly the 20 m isobath. Existing canopy kelp of Eualaria (Alaria) fistulosa, as well as limited understory algal species and associated fauna (e.g., urchin barrens) on the hard substratum were apparently buried following the eruption. Samples and observations revealed the substrate around the island in 2009 was comprised almost entirely of medium and coarse sands with a depauperate benthic community, dominated by opportunistic pontogeneiid amphipods. Comparisons of habitat and biological communities with other nearby Aleutian Islands, as well as with the Icelandic volcanic island of Surtsey, confirm dramatic reductions in flora and fauna consistent with an early stage of recovery from a large-scale disturbance event. ?? 2010 Regents of the University of Colorado.

  17. Iron fertilisation of the ocean through major volcanic eruptions. A case study of the Kasatochi eruption 2008

    NASA Astrophysics Data System (ADS)

    Lindenthal, A.; Langmann, B.; Hort, M.; Hoshyaripour, G.; Paetsch, J.; Lorkowski, I.

    2012-04-01

    Until recently it was more or less common sense that once volcanic ash enters the ocean it simply deposits into the sediments without any further impact on ocean biochemistry. This view has been notably revised after the eruption of Kasatochi volcano in 2008. During the eruption significant amounts of ash were deposited into oceanic NE Pacific. The NE Pacific is known as a high-nutrient-low-chlorophyll (HNLC) region where algae growth is limited by the bio-available, i.e. soluble iron. These bio-available iron salts residing on the volcanic ash are most likely formed by gas-ash/aerosol interactions inside the volcanic plume. The physico-chemical mechanisms behind the processes contributing to bio-available iron production in volcanic plumes, however, are still poorly constrained. As the eruption occurred in early August, the atmospheric and oceanic conditions were favourable to generate a massive phytoplankton bloom as was observed by satellite instruments and in-situ measurements. Here we investigate this event with the marine biogeochemical model ECOHAM, which is a regional scale three-dimensional ocean biogeochemistry model, coupled to the hydrodynamic model HAMSON. It has been successfully applied mainly over the NW European continental shelf area where iron limitation does not play a role. For applications of this model to the eruption of Kasatochi volcano, an iron cycle model has been implemented, which considers the influence of iron addition to the euphotic zone on diatoms, flagellates, and carbon dioxide concentrations. This model-approach assumes that all dissolved iron in the first meters of seawater is bio-available for phytoplankton uptake. It describes the limitation of phytoplankton growth rates by iron in addition to the limitation by the macro-nutrients nitrogen, phosphate and silicate as well as by light. The surface ocean iron input associated with the eruption of Kasatochi volcano has been determined by an atmospheric-aerosol model to be on the

  18. Constraining the Spatial and Temporal Variability of Atmospheric Conditions to Explore the Infrasound Detection of Volcanic Eruptions in Alaska

    NASA Astrophysics Data System (ADS)

    Iezzi, A. M.; Schwaiger, H. F.; Fee, D.; Haney, M. M.

    2015-12-01

    Alaska's over 50 historically active volcanoes span 2,500 kilometers, and their eruptions pose great threats to the aviation industry. This makes both prompt observations of explosion onsets and changes in intensity a necessity. Due to their expansive range and remoteness, these volcanoes are predominantly monitored by local seismic networks, remote observations including satellite imagery and infrasound sensors. Infrasound is an especially crucial tool in this area because infrasound data collection is not obstructed by frequent cloud cover (as in satellite imagery) and infrasound waves can travel hundreds to thousands of kilometers. However, infrasound station coverage is relatively sparse and strong wind and temperature gradients in the atmosphere create multiple waveguides and shadow zones where the propagation of infrasound is enhanced and diminished, respectively. To accurately constrain volcanic source information and the long-range propagation of infrasound waves, a detailed characterization of the spatial and temporal variability of the atmosphere is vital. These properties can be constrained using a ground-to-space model similar to that of Drob et al. (2003) based upon varied meteorological observations and applied to infrasound waves to model the propagation of infrasound. Here we present the first results of a re-analysis system constructed by the Alaska Volcano Observatory to accurately characterize and model long-range infrasound propagation from volcanic eruptions. We select a number of case studies to examine infrasound detections (or lack thereof) from recent eruptions of Alaskan volcanoes, including the November 2014 eruption of Pavlof Volcano and July 2015 eruption of Cleveland Volcano. Detailed examination of the acoustic propagation conditions will provide additional insight into detection capability and eruption dynamics with future work aiming to implement real-time long-range infrasound propagation modeling.Drob, Douglas P., J. M. Picone

  19. Infrasonic observations of the June 2009 Sarychev Peak eruption, Kuril Islands: Implications for infrasonic monitoring of remote explosive volcanism

    NASA Astrophysics Data System (ADS)

    Matoza, Robin S.; Le Pichon, Alexis; Vergoz, Julien; Herry, Pascal; Lalande, Jean-Marie; Lee, Hee-il; Che, Il-Young; Rybin, Alexander

    2011-02-01

    Sarychev Peak (SP), located on Ostrov Matua, Kurils, erupted explosively during 11-16 June 2009. Whereas remote seismic stations did not record the eruption, we report atmospheric infrasound (acoustic wave ~ 0.01-20 Hz) observations of the eruption at seven infrasound arrays located at ranges of ~ 640-6400 km from SP. The infrasound arrays consist of stations of the International Monitoring System global infrasound network and additional stations operated by the Korea Institute of Geoscience and Mineral Resources. Signals at the three closest recording stations IS44 (643 km, Petropavlovsk-Kamchatskiy, Kamchatka Krai, Russia), IS45 (1690 km, Ussuriysk, Russia), and IS30 (1774 km, Isumi, Japan) represent a detailed record of the explosion chronology that correlates well with an eruption chronology based on satellite data (TERRA, NOAA, MTSAT). The eruption chronology inferred from infrasound data has a higher temporal resolution than that obtained with satellite data. Atmosphere-corrected infrasonic source locations determined from backazimuth cross-bearings of first-arrivals have a mean centroid ~ 15 km from the true location of SP. Scatter in source locations of up to ~ 100 km result from currently unresolved details of atmospheric propagation and source complexity. We observe systematic time-variations in trace-velocity, backazimuth deviation, and signal frequency content at IS44. Preliminary investigation of atmospheric propagation from SP to IS44 indicates that these variations can be attributed to solar tide variability in the thermosphere. It is well known that additional information about active volcanic processes can be learned by deploying infrasonic sensors with seismometers at erupting volcanoes. This study further highlights the significant potential of infrasound arrays for monitoring volcanic regions such as the Kurils that have only sparse seismic network coverage.

  20. Impacts of high-latitude volcanic eruptions on ENSO and AMOC

    PubMed Central

    Pausata, Francesco S. R.; Chafik, Leon; Caballero, Rodrigo; Battisti, David S.

    2015-01-01

    Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is roughly 2–3 y. Attention has consequently focused on their short-term impacts, whereas the long-term, ocean-mediated response has not been well studied. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts are thought to be merely hemispheric rather than global. No study to date has investigated the long-term effects of high-latitude eruptions. Here, we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce an El Niño-like anomaly, in the equatorial Pacific during the first 8–9 mo after the start of the eruption. The hemispherically asymmetric cooling shifts the Intertropical Convergence Zone southward, triggering a weakening of the trade winds over the western and central equatorial Pacific that favors the development of an El Niño-like anomaly. In the model used here, the specified high-latitude eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first 25 y after the eruption, followed by a weakening lasting at least 35 y. The long-lived changes in the AMOC strength also alter the variability of the El Niño–Southern Oscillation (ENSO). PMID:26504201

  1. Impacts of high-latitude volcanic eruptions on ENSO and AMOC.

    PubMed

    Pausata, Francesco S R; Chafik, Leon; Caballero, Rodrigo; Battisti, David S

    2015-11-10

    Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is roughly 2-3 y. Attention has consequently focused on their short-term impacts, whereas the long-term, ocean-mediated response has not been well studied. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts are thought to be merely hemispheric rather than global. No study to date has investigated the long-term effects of high-latitude eruptions. Here, we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce an El Niño-like anomaly, in the equatorial Pacific during the first 8-9 mo after the start of the eruption. The hemispherically asymmetric cooling shifts the Intertropical Convergence Zone southward, triggering a weakening of the trade winds over the western and central equatorial Pacific that favors the development of an El Niño-like anomaly. In the model used here, the specified high-latitude eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first 25 y after the eruption, followed by a weakening lasting at least 35 y. The long-lived changes in the AMOC strength also alter the variability of the El Niño-Southern Oscillation (ENSO). PMID:26504201

  2. Impacts of high-latitude volcanic eruptions on ENSO and AMOC.

    PubMed

    Pausata, Francesco S R; Chafik, Leon; Caballero, Rodrigo; Battisti, David S

    2015-11-10

    Large volcanic eruptions can have major impacts on global climate, affecting both atmospheric and ocean circulation through changes in atmospheric chemical composition and optical properties. The residence time of volcanic aerosol from strong eruptions is roughly 2-3 y. Attention has consequently focused on their short-term impacts, whereas the long-term, ocean-mediated response has not been well studied. Most studies have focused on tropical eruptions; high-latitude eruptions have drawn less attention because their impacts are thought to be merely hemispheric rather than global. No study to date has investigated the long-term effects of high-latitude eruptions. Here, we use a climate model to show that large summer high-latitude eruptions in the Northern Hemisphere cause strong hemispheric cooling, which could induce an El Niño-like anomaly, in the equatorial Pacific during the first 8-9 mo after the start of the eruption. The hemispherically asymmetric cooling shifts the Intertropical Convergence Zone southward, triggering a weakening of the trade winds over the western and central equatorial Pacific that favors the development of an El Niño-like anomaly. In the model used here, the specified high-latitude eruption also leads to a strengthening of the Atlantic Meridional Overturning Circulation (AMOC) in the first 25 y after the eruption, followed by a weakening lasting at least 35 y. The long-lived changes in the AMOC strength also alter the variability of the El Niño-Southern Oscillation (ENSO).

  3. 2008 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    Neal, Christina A.; McGimsey, Robert G.; Dixon, James P.; Cameron, Cheryl E.; Nuzhdaev, Anton A.; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest or suspected unrest at seven separate volcanic centers in Alaska during 2008. Significant explosive eruptions at Okmok and Kasatochi Volcanoes in July and August dominated Observatory operations in the summer and autumn. AVO maintained 24-hour staffing at the Anchorage facility from July 12 through August 28. Minor eruptive activity continued at Veniaminof and Cleveland Volcanoes. Observed volcanic unrest at Cook Inlet's Redoubt Volcano presaged a significant eruption in the spring of 2009. AVO staff also participated in hazard communication regarding eruptions or unrest at nine volcanoes in Russia as part of a collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  4. Dispersion of the Volcanic Sulfate Cloud from the Mount Pinatubo Eruption

    NASA Technical Reports Server (NTRS)

    Aquila, Valentina; Oman, Luke D.; Stolarski, Richard S.; Colarco, Peter R.; Newman, Paul A.

    2012-01-01

    We simulate the transport of the volcanic cloud from the 1991 eruption of Mount Pinatubo with the GEOS-5 general circulation model. Our simulations are in good agreement with observational data. We tested the importance of initial condition corresponding to the specific meteorological situation at the time of the eruption by employing reanalysis from MERRA. We found no significant difference in the transport of the cloud. We show how the inclusion of the interaction between volcanic sulfate aerosol and radiation is essential for a reliable simulation of the transport of the volcanic cloud. The absorption of long wave radiation by the volcanic sulfate induces a rising of the volcanic cloud up to the middle stratosphere, combined with divergent motion from the latitude of the eruption to the tropics. Our simulations indicate that the cloud diffuses to the northern hemisphere through a lower stratospheric pathway, and to mid- and high latitudes of the southern hemisphere through a middle stratospheric pathway, centered at about 30 hPa. The direction of the middle stratospheric pathway depends on the season. We did not detect any significant change of the mixing between tropics and mid- and high latitudes in the southern hemisphere.

  5. 1995 volcanic activity in Alaska and Kamchatka: summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.

    1996-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptive activity or suspected volcanic activity (SVA) at 6 volcanic centers in 1995: Mount Martin (Katmai Group), Mount Veniaminof, Shishaldin, Makushin, Kliuchef/Korovin, and Kanaga. In addition to responding to eruptive activity at Alaska volcanoes, AVO also disseminated information for the Kamchatkan Volcanic Eruption Response Team (KVERT) on the 1995 eruptions of 2 Russian volcanoes: Bezymianny and Karymsky. This report summarizes volcanic activity in Alaska during 1995 and the AVO response, as well as information on the 2 Kamchatkan eruptions. Only those reports or inquiries that resulted in a "significant" investment of staff time and energy (here defined as several hours or more for reaction, tracking, and follow-up) are included. AVO typically receives dozens of phone calls throughout the year reporting steaming, unusual cloud sightings, or eruption rumors. Most of these are resolved quickly and are not tabulated here as part of the 1995 response record.

  6. Diverse Eruptions at Approximately 2,200 Years B.P. on the Great Rift, Idaho: Inferences for Magma Dynamics Along Volcanic Rift Zones

    NASA Technical Reports Server (NTRS)

    Hughes, S. S.; Nawotniak, S. E. Kobs; Borg, C.; Mallonee, H. C.; Purcell, S.; Neish, C.; Garry, W. B.; Haberle, C. W.; Lim, D. S. S.; Heldmann, J. L.

    2016-01-01

    Compositionally and morphologically diverse lava flows erupted on the Great Rift of Idaho approximately 2.2 ka (kilo-annum, 1000 years ago) during a volcanic "flare-up" of activity following an approximately 2 ky (kiloyear, 1000 years) hiatus in eruptions. Volcanism at Craters of the Moon (COTM), Wapi and Kings Bowl lava fields around this time included primitive and evolved compositions, separated over 75 kilometers along the approximately 85 kilometers-long rift, with striking variability in lava flow emplacement mechanisms and surface morphologies. Although the temporal associations may be coincidental, the system provides a planetary analog to better understand magma dynamics along rift systems, including that associated with lunar floor-fractured craters. This study aims to help bridge the knowledge gap between ancient rift volcanism evident on the Moon and other terrestrial planets, and active rift volcanism, e.g., at Hawai'i and Iceland.

  7. Impact of explosive volcanic eruptions around Vesuvius: a story of resilience in Roman time

    NASA Astrophysics Data System (ADS)

    Scarpati, Claudio; Perrotta, Annamaria; De Simone, Girolamo Ferdinando

    2016-03-01

    Large explosive eruptions have reshaped the landscape around Vesuvius many times in prehistoric and historical times. Previous stratigraphic surveys suggested that people living in this area have probably abandoned their settlements (in the Bronze Age) or towns and villas (in the Roman period) for centuries after each major plinian eruption. New archaeological excavations on the northern slope of Vesuvius suggest a much more intriguing scenario. At Pollena Trocchia, an ongoing excavation has shown the superimposition of three different Roman structures, sandwiched between the deposits of the AD 79, AD 472, and AD 512 Vesuvius eruptions. Each of these eruptions more or less completely destroyed and buried the buildings under meters of volcanic products. Surprisingly, after a few years or decades, a new settlement was established exactly on the top of the buried one, indicating the immediate recovery of part of the devastated area. Our research documents the destruction of Roman buildings by volcanic eruptions over a period of five centuries (first to sixth century AD) and provides new insight into human behavior after major explosive eruptions.

  8. Sulfur isotopic characteristics of volcanic products from the September 2014 Mount Ontake eruption, Japan

    NASA Astrophysics Data System (ADS)

    Ikehata, Kei; Maruoka, Teruyuki

    2016-07-01

    Components and sulfur isotopic compositions of pyroclastic materials from the 2014 Mt. Ontake eruption were investigated. The volcanic ash samples were found to be composed of altered volcanic fragments, alunite, anhydrite, biotite, cristobalite, gypsum, ilmenite, kaolin minerals, native sulfur, orthopyroxene, plagioclase, potassium feldspar, pyrite, pyrophyllite, quartz, rutile, and smectite, and most of these minerals were likely derived from the acidic alteration zones of Mt. Ontake. The absence of juvenile material in the eruptive products indicates that the eruption was phreatic. The sulfur isotopic compositions of the water-leached sulfate, hydrochloric acid-leached sulfate, acetone-leached native sulfur, and pyrite of the samples indicate that these sulfur species were produced by disproportionation of magmatic SO2 in the hydrothermal system at temperatures of 270-281 °C. This temperature range is consistent with that inferred from the hydrothermal mineral assemblage (e.g., pyrophyllite and rutile) in the 2014 pyroclastic materials (200-300 °C). Except for the sulfur isotopic compositions of anhydrite, which may have been altered by incorporation of sulfate minerals in a fumarolic area with lower sulfur isotopic values into the underground materials during the 1979 eruption, no significant differences in the mineral assemblages and sulfur isotopic compositions of the pyroclastic materials were identified between the products of the 2014 and 1979 Ontake phreatic eruptions, which suggests geochemical similarities in the underlying hydrothermal systems before the 2014 and 1979 eruptions.

  9. Constraining timescales of pre-eruptive events within large silicic volcanic centers

    NASA Astrophysics Data System (ADS)

    Rubin, A. E.; Cooper, K. M.; Kent, A. J.; Costa Rodriguez, F.; Till, C. B.

    2015-12-01

    Large silicic volcanic centers produce catastrophic supervolcanic eruptions. As a result it is necessary to understand what's happening within these centers, and on what timescales, in order to anticipate and prepare for such eruptions. A widely accepted model for many rhyolitic volcanic systems is that of a long-lived mush from which melt is periodically extracted and erupted. However, what remains unclear are 1) the specific processes by which melt is amalgamated and extracted from this mush and 2) the timescales over which these occur. Processes occurring close to eruption likely include amalgamation (and potentially homogenization) of melt, melt extraction, crystallization of major phases, and final magma ascent. Numerical and geochemical models have been used to constrain timescales of mush rejuvenation, and contrast between short timescales for mush reactivation (e.g., <<1000 years, depending on the reservoir) and others demonstrating much longer timescales at super-solidus conditions (e.g., 100s of kyrs). Timescales calculated from intra-crystalline diffusion profiles suggest that many crystals spend very short amounts of time (decades to centuries) at near-solidus temperatures prior to eruption. At the Okataina Volcanic Center (OVC) in New Zealand, geochemical and isotopic data suggest that melts are extracted from a long-lived, heterogeneous mush prior to eruption. Despite this protracted existence, combined U-series ages and diffusion profiles in OVC zircon and plagioclase crystals suggest that crystallization often occurs within the final hundreds to thousands of years prior to eruption, and at most, a few percent of a crystal's total history is spent at above-solidus conditions. Within these brief amounts of time, diffusion techniques can be linked to specific pre-eruptive processes in order to constrain timescales of melt extraction from a mush (likely decades to centuries), intrusions of new melt and/or magma mixing (likely years to decades), and

  10. 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.

  11. Evaluation of sulfur dioxide emissions from explosive volcanism: the 1982-1983 eruptions of Galunggung, Java, Indonesia

    USGS Publications Warehouse

    Bluth, G.J.S.; Casadevall, T.J.; Schnetzler, C.C.; Doiron, S.D.; Walter, Louis S.; Krueger, A.J.; Badruddin, M.

    1994-01-01

    Galunggung volcano, Java, awoke from a 63-year quiescence in April 1982, and erupted sporadically through January 1983. During its most violent period from April to October, the Cikasasah Volcano Observatory reported 32 large and 56 moderate to small eruptions. From April 5 through September 19 the Total Ozone Mapping Spectrometer (TOMS), carried on NASA's Nimbus-7 satellite, detected and measured 24 different sulfur dioxide clouds; an estimated 1730 kilotons (kt) of SO2 were outgassed by these explosive eruptions. The trajectories, and rapid dispersion rates, of the SO2 clouds were consistent with injection altitudes below the tropopause. An additional 300 kt of SO2 were estimated to have come from 64 smaller explosive eruptions, based on the detection limit of the TOMS instrument. For the first time, an extended period of volcanic activity was monitored by remote sensing techniques which enabled observations of both the entire SO2 clouds produced by large explosive eruptions (using TOMS), and the relatively lower levels of SO2 emissions during non-explosive outgassing (using the Correlation Spectrometer, or COSPEC). Based on COSPEC measurements from August 1982 to January 1983, and on the relationship between explosive and non-explosive degassing, approximately 400 kt of SO2 were emitted during non-explosive activity. The total sulfur dioxide outgassed from Galunggung volcano from April 1982 to January 1983 is calculated to be 2500 kt (?? 30%) from both explosive and non-explosive activity. While Galunggung added large quantities of sulfur dioxide to the atmosphere, its sporadic emissions occurred in relatively small events distributed over several months, and reached relatively low altitudes, and are unlikely to have significantly affected aerosol loading of the stratosphere in 1982 by volcanic activity. ?? 1994.

  12. Classifying Volcanic Activity Using an Empirical Decision Making Algorithm

    NASA Astrophysics Data System (ADS)

    Junek, W. N.; Jones, W. L.; Woods, M. T.

    2012-12-01

    Detection and classification of developing volcanic activity is vital to eruption forecasting. Timely information regarding an impending eruption would aid civil authorities in determining the proper response to a developing crisis. In this presentation, volcanic activity is characterized using an event tree classifier and a suite of empirical statistical models derived through logistic regression. Forecasts are reported in terms of the United States Geological Survey (USGS) volcano alert level system. The algorithm employs multidisciplinary data (e.g., seismic, GPS, InSAR) acquired by various volcano monitoring systems and source modeling information to forecast the likelihood that an eruption, with a volcanic explosivity index (VEI) > 1, will occur within a quantitatively constrained area. Logistic models are constructed from a sparse and geographically diverse dataset assembled from a collection of historic volcanic unrest episodes. Bootstrapping techniques are applied to the training data to allow for the estimation of robust logistic model coefficients. Cross validation produced a series of receiver operating characteristic (ROC) curves with areas ranging between 0.78-0.81, which indicates the algorithm has good predictive capabilities. The ROC curves also allowed for the determination of a false positive rate and optimum detection for each stage of the algorithm. Forecasts for historic volcanic unrest episodes in North America and Iceland were computed and are consistent with the actual outcome of the events.

  13. The 2006 Eruption of Raoul Volcano (Kermadecs): A Phreato-magmatic Event From a Hydrothermally-Sealed Volcanic Conduit System.

    NASA Astrophysics Data System (ADS)

    Christenson, B. W.; Reyes, A. G.; Werner, C. A.

    2006-12-01

    The March 17, 2006 eruption from Raoul volcano (Kermadec Islands, NZ), which tragically claimed the life of NZ Department of Conservation staff member Mark Kearney, is being interpreted as a magmatic-hydrothermal event triggered by shaking associated with regional earthquake swarm activity. Although the eruption released ca. 200 T of SO2, thus confirming its magmatic nature, it occurred without significant precursory volcanic seismicity, and without any of the precursory responses of the volcanic hydrothermal system which were observed prior to the last eruption in 1964. Raoul Island has a long and varied eruption history dating back > 1.4 ma, and has been hydrothermally active throughout historic time. Present day fumarolic and hotspring discharges within Raoul caldera point to the existence of a small but well established, mixed meteoric - seawater hydrothermal system within the volcano. Magmatic signatures are apparent in fumarolic gas discharges, but are heavily masked by their interaction with hydrothermal system fluids (eg. near complete scrubbing of sulphur and halogen gases from the boiling point fumarolic discharges). A diffuse degassing study conducted in 2004 revealed that ca. 80 T/d CO2 is passively discharged from the volcano, suggesting that ongoing (albeit low level) convective degassing of magma occurs at depth. Interestingly, vent locations from the 2006 eruption correspond to areas of relatively low CO2 discharge on the crater floor in 2004. This, in conjunction with the preliminary findings of abundant hydrothermal mineralisation (calcite, anhydrite, quartz) in eruption ejecta, suggests that the main volcanic conduits had become effectively sealed during the interval since the last eruption. Calcite-hosted fluid inclusions are CO2 clathrate-bearing, and have relatively low homogenisation temperatures (165-180 °C), suggesting that the seal environment was both gas-charged and shallowly seated (< 200 m). Shaking associated with the regional

  14. 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.

  15. 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

  16. Storage conditions and eruptive dynamics of central versus flank eruptions in volcanic islands: The case of Tenerife (Canary Islands, Spain)

    NASA Astrophysics Data System (ADS)

    Andújar, Joan; Costa, Fidel; Scaillet, Bruno

    2013-06-01

    We report the results of phase equilibrium experiments on a phonolite produced during one of the most voluminous flank eruptions (ca. 1 km3) of the Teide-Pico Viejo complex (Tenerife Island). Combined with previous experimental and volcanological data we address the factors that control the structure of the phonolitic plumbing system of Teide-Pico Viejo stratovolcanoes. The Roques Blancos phonolite erupted ca 1800 BP and contains ~ 14 wt.% phenocrysts, mainly anorthoclase, biotite, magnetite, diopside and lesser amounts of ilmenite. Crystallization experiments were performed at temperatures of 900 °C, 850 °C and 800 °C, in the pressure range 200 MPa to 50 MPa. The oxygen fugacity (fO2) was varied between NNO + 0.3 (0.3 log units above to the Ni-NiO solid buffer) to NNO-2, whilst dissolved water contents varied from 7 wt.% to 1.5 wt.%. The comparison between natural and experimental phase proportions and compositions, including glass, indicates that the phonolite magma was stored prior to eruption at 900 ± 15 °C, 50 ± 15 MPa, with about 2.2 wt.% H2O dissolved in the melt, at an oxygen fugacity of NNO-0.5 (± 0.5). The difference in composition between the rim and the cores of the natural anorthoclase phenocrysts suggests that the phonolite was heated by about 50 °C before the eruption, upon intrusion of a hotter tephriphonolitic magma. The comparison between the storage conditions of Roques Blancos and those inferred for other phonolites of the Teide-Pico Viejo volcanic complex shows that flank eruptions are fed by reservoirs located at relatively shallow depths (1-2 km) compared to those feeding Teide central eruptions (5 km).

  17. Multi-decadal satellite measurements of passive and eruptive volcanic SO2 emissions

    NASA Astrophysics Data System (ADS)

    Carn, Simon; Yang, Kai; Krotkov, Nickolay; Prata, Fred; Telling, Jennifer

    2015-04-01

    Periodic injections of sulfur gas species (SO2, H2S) into the stratosphere by volcanic eruptions are among the most important, and yet unpredictable, drivers of natural climate variability. However, passive (lower tropospheric) volcanic degassing is the major component of total volcanic emissions to the atmosphere on a time-averaged basis, but is poorly constrained, impacting estimates of global emissions of other volcanic gases (e.g., CO2). Stratospheric volcanic emissions are very well quantified by satellite remote sensing techniques, and we report ongoing efforts to catalog all significant volcanic SO2 emissions into the stratosphere and troposphere since 1978 using measurements from the ultraviolet (UV) Total Ozone Mapping Spectrometer (TOMS; 1978-2005), Ozone Monitoring Instrument (OMI; 2004 - present) and Ozone Mapping and Profiler Suite (OMPS; 2012 - present) instruments, supplemented by infrared (IR) data from HIRS, MODIS and AIRS. The database, intended for use as a volcanic forcing dataset in climate models, currently includes over 600 eruptions releasing a total of ~100 Tg SO2, with a mean eruption discharge of ~0.2 Tg SO2. Sensitivity to SO2 emissions from smaller eruptions greatly increased following the launch of OMI in 2004, but uncertainties remain on the volcanic flux of other sulfur species other than SO2 (H2S, OCS) due to difficulty of measurement. Although the post-Pinatubo 1991 era is often classified as volcanically quiescent, many smaller eruptions (Volcanic Explosivity Index [VEI] 3-4) since 2000 have injected significant amounts of SO2 into the upper troposphere - lower stratosphere (UTLS), peaking in 2008-2011. We also show how even smaller (VEI 2) tropical eruptions can impact the UTLS and sustain above-background stratospheric aerosol optical depth, thus playing a role in climate forcing on short timescales. To better quantify tropospheric volcanic degassing, we use ~10 years of operational SO2 measurements by OMI to identify the

  18. Tree-Ring Evidence for Volcanic Eruption Effects on Temperate and Boreal Tree Net Primary Productivity

    NASA Astrophysics Data System (ADS)

    Krakauer, N. Y.; Smith, N. V.; Randerson, J. T.

    2003-12-01

    The 1991 Pinatubo eruption and the apparent increased terrestrial carbon uptake in 1992 and 1993 have motivated interest in understanding the impact on plant productivity of the climate and radiative change resulting from volcanic eruptions that generate large stratospheric aerosol loadings. We used tree ring width series to look for anomalously high or low tree growth following 10 large eruptions since 1500 (not including Pinatubo) that resulted in stratospheric aerosol loadings comparable to Pinatubo's. We obtained crossdated ring width series from the International Tree Ring Data Bank, developed regional mean width indices, and used a Monte Carlo approach to test for significant departures in the indices following eruptions. Boreal zone trees (north of 50° N) showed significantly reduced widths ( ˜5% below average) for several years centered around years 4-6 after eruptions. Temperate zone (35° -50° N) trees in eastern North America showed significantly increased (by ˜6%) widths on years 0-2 after eruptions. Temperate zone trees in western North America showed a smaller increase, and trees in Europe showed no increase. We tentatively suggest that eruption-induced cooling causes the growth reduction in boreal trees, whereas the differing regional patterns found in temperate trees could be due to a combination of differences in eruption climate effects between regions, temperature versus moisture limited growth depending on ambient climate, and enhancement of tree light use efficiency in closed-canopy forest because of an increase in diffuse light fraction. Our findings invite additional research to clarify how regional climate and ecology modulate the effects of eruptions on tree growth and to assess the net effect of eruptions on global plant productivity. A series of annual tree carbon increment compiled from coring in plots of Harvard Forest, Massachusetts (42.5° N, 72.2° W), as well as other series for eastern North America do not show increased growth

  19. Coupled evolution of magma chambers and flow in conduits during large volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Karlstrom, L.; Manga, M.; Rudolph, M. L.

    2010-12-01

    The largest silicic and mafic volcanic eruptions in the geologic record, Supervolcano and Large Igneous Province (LIP) eruptions, are distinguished by differences in surface emplacement mode, geologic context, magma volatile content, viscosity, and reservoir depth. However, these large eruptions also share several common features. Individual eruptions of both types emplace roughly the same total volume (10^3 - 10^4 km^3) of remarkably homogeneous magma that likely comes from a single reservoir. In addition, they both release large quantities of volatiles, and hence individual eruptions may significantly perturb global climate. We have developed a model that couples conduit flow and magma chamber deformation, allowing us to study both eruption types. Steady, one-dimensional multiphase flow of magma containing crystals, exsolved water, and CO_2 in a cylindrical conduit is coupled to pressure evolution within an ellipsoidal magma chamber beneath a free surface. LIP eruptions are characterized by gas-driven flow of mafic lava that may be sustained past the cessation of chamber overpressure, much like a siphon. Eruptions cease when the yield strength of the country rocks is reached and the (generally Moho-level) chamber or the conduit implodes, resulting in steady discharge and atmospheric volatile loading. In contrast, more shallow silicic lavas such as the Fish Canyon Tuff erupt through rapid mobilization of a long-lived crystal-rich mush. The crystal-rich mush is a yield strength fluid, which we model using the von Mises criterion for mobilization. If the trigger for mobilization of the mush leads directly to eruption, time-progressive yielding due to mass removal results in a fluid magma chamber that grows as the eruption proceeds, until free-surface stresses induce roof collapse and caldera formation. Chamber pressure evolution may be buffered by the mobilization of the mush, maintaining overpressure and high discharge throughout the eruption. This model suggests

  20. Magmatic vapor source for sulfur dioxide released during volcanic eruptions: Evidence from Mount Pinatubo

    USGS Publications Warehouse

    Wallace, P.J.; Gerlach, T.M.

    1994-01-01

    Sulfur dioxide (SO2) released by the explosive eruption of Mount Pinatubo on 15 June 1991 had an impact on climate and stratospheric ozone. The total mass of SO2 released was much greater than the amount dissolved in the magma before the eruption, and thus an additional source for the excess SO2 is required. Infrared spectroscopic analyses of dissolved water and carbon dioxide in glass inclusions from quartz phenocrysts demonstrate that before eruption the magma contained a separate, SO2-bearing vapor phase. Data for gas emissions from other volcanoes in subduction-related arcs suggest that preeruptive magmatic vapor is a major source of the SO2 that is released during many volcanic eruptions.

  1. Sulfur and halogen chemistry of the stratosphere and of volcanic eruption plumes

    NASA Technical Reports Server (NTRS)

    Lazrus, A. L.; Cadle, R. D.; Gandrud, B. W.; Greenberg, J. P.; Huebert, B. J.; Rose, W. I., Jr.

    1979-01-01

    The major eruption of Volcan de Fuego caused an enhancement of 1.6 x 10 to the 9 kg of SO4(-) in the stratosphere 6 months after the eruption. Measurable changes in nitric acid vapor and particulate chloride were not observed. Subsequent data suggests that HCl was not injected into the stratosphere. The first simultaneous measurement of halogen and sulfur content of gases and particles in explosive eruption plumes is reported. The average percents of elements in particles were sulfur, 2.5 + or - 2.1; chlorine, 18 + or - 12; and fluorine, 38 + or - 29. The average molecular ratio of HCl/SO2 and HCl/HF were 0.41 + or - 0.26 and 14 + or - 12 in the Guatemalan eruption plumes.

  2. Sponge Cake or Champagne? Bubbles, Magmatic Degassing and Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Cashman, K.; Pioli, L.; Belien, I.; Wright, H.; Rust, A.

    2007-12-01

    Vesiculation is an unavoidable consequence of magma decompression; the extent to which bubbles travel with ascending magma or leave the system by separated or permeable flow will determine the nature of the ensuing eruption. Bubbles travel with the melt from which they exsolve if the rise time of bubbles through the melt (the 'drift velocity') is much less than the rise rate of the magma (sponge cake). This condition is most likely to be met in viscous melts (where bubble rise velocities are low) and in melts that experience rapid decompression (high ascent velocities). Under these conditions, bubble expansion within the melt continues until sufficient bubble expansion causes coalescence and the development of a permeable network. Typical pumice vesicularities of 70-80% and permeabilities of 10-12 m2 constrain this limit under conditions appropriate for subplinian to plinian eruptions (mass fluxes > 106 kg/s). Slower rise rates (and lower mass fluxes) that characterize effusive eruptions produce silicic lavas with a wider range of vesicularities. In general, permeability decreases with decreasing sample vesicularity as bubbles deform (as evidenced by anisotropy in permeability and electrical conductivity) and pore apertures diminish. Degassing efficiency (and resulting densification of magma within the conduit) under these conditions is determined by permeability and the time allowed for gas escape. Bubbles rise through the melt if the drift velocity exceeds the velocity of magma ascent (champagne). This condition is most easily met in volatile-rich, low viscosity (mafic) melts at low to moderate fluxes. At very low magma flux, magma eruption rate is determined by the extent to which magma is entrained and ejected by rising gases (strombolian eruptions); when bubbles are too small, or are rising too slowly, they may not break the surface at all, but instead may be concentrated in a near-surface layer (surface foam). As the magma flux increases, segregation of

  3. On the Generation of Multiple Atmospheric Pressure Waves Observed During Violent Volcanic Eruptions.

    NASA Astrophysics Data System (ADS)

    Medici, E. F.; Waite, G. P.

    2015-12-01

    One or more atmospheric pressure waves followed by a supersonic jet may be generated during the over pressurized vapor-solid-liquid mixture ejection of a violent volcanic eruption. The source of these multiple atmospheric pressure waves could have different origins. Among the physical mechanisms that could explain these behaviors are pulsating eruptions, the dynamics of shock waves, coupled pressure wave-supersonic jet interaction, or a combination of all these factors. In order to elucidate the causes of these complex fluid flow dynamics, a series of analog volcanic eruption experiments using an atmospheric shock tube were performed. During the testing, single and multiple pressure waves and the subsequent supersonic jet were generated. The controlled laboratory conditions enable studies of the most relevant variables potentially responsible for the formation of the multiple pressure waves. The tests were performed using dry, compressed nitrogen at standard room temperature that was free of particles. Yet, under this idealization of a real volcanic eruption, multiple pressure waves were observed on the high-speed video imaging and recorded on the pressure transducer. The amount of energy being released on each test was varied to achieve different discharge dynamics and the formation of single and multiple pressure waves. The preliminary experimental observations indicate a coupled pressure wave-jet interaction as source of multiple pressure waves.

  4. What caused the mass extinction A volcanic eruption

    SciTech Connect

    Courtillot, V.E. )

    1990-10-01

    The authors proposes that dust, carbon dioxide and other emissions from an episode of enormous volcanism that formed the basaltic Deccan Traps in India produced the climate changes that led to the mass extinction at the end of the Cretaceous period. The iridium could, he says, just as easily have risen from the earth's mantle. The sheer size of the Deccan Traps suggests that their formation must have been an important event in the earth's history. An important, unresolved question was whether the data and duration of Deccan volcanism are compatible with the age and thickness of the KT boundary. Until recently the lava samples from the Deccan Traps were thought to range in age from 80 to 30 million years (estimated by measuring the decay of the radioactive isotope potassium 40 in rocks). The author presents data suggesting volcanism could not have lasted much more than one million years and was roughly simultaneous with the extinction at the end of the Cretaceous period.

  5. Global Temperature Response to the Major Volcanic Eruptions in Multiple Reanalysis Datasets

    NASA Astrophysics Data System (ADS)

    Fujiwara, M.; Hibino, T.; Mehta, S. K.; Gray, L. J.; Mitchell, D.; Anstey, J.

    2015-12-01

    Global temperature response to the eruptions of Mount Agung in 1963, El Chichón in 1982 and Mount Pinatubo in 1991 is investigated using nine reanalysis datasets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979-2009 (for eight reanalysis datasets) and 1958-2001 (for four reanalysis datasets), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately. In response to the Mount Pinatubo eruption, most reanalysis datasets show strong warming signals (up to 2-3 K for one-year average) in the tropical lower stratosphere and weak cooling signals (down to -1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. Comparison of the results from several different reanalysis datasets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis datasets.

  6. Multiple dendrochronological responses to the eruption of Cinder Cone, Lassen Volcanic National Park, California

    USGS Publications Warehouse

    Sheppard, P.R.; Ort, M.H.; Anderson, K.C.; Clynne, M.A.; May, E.M.

    2009-01-01

    Two dendrochronological properties – ring width and ring chemistry – were investigated in trees near Cinder Cone in Lassen Volcanic National Park, northeastern California, for the purpose of re-evaluating the date of its eruption. Cinder Cone is thought to have erupted in AD 1666 based on ring-width evidence, but interpreting ring-width changes alone is not straightforward because many forest disturbances can cause changes in ring width. Old Jeffrey pines growing in Cinder Cone tephra and elsewhere for control comparison were sampled. Trees growing in tephra show synchronous ring-width changes at AD 1666, but this ring-width signal could be considered ambiguous for dating the eruption because changes in ring width can be caused by other events. Trees growing in tephra also show changes in ring phosphorus, sulfur, and sodium during the late 1660s, but inter-tree variability in dendrochemical signals makes dating the eruption from ring chemistry alone difficult. The combination of dendrochemistry and ring-width signals improves confidence in dating the eruption of Cinder Cone over the analysis of just one ring-growth property. These results are similar to another case study using dendrochronology of ring width and ring chemistry at Parícutin, Michoacán, Mexico, a cinder cone that erupted beginning in 1943. In both cases, combining analysis with ring width and ring chemistry improved confidence in the dendro-dating of the eruptions.

  7. Retrieving eruptive vent conditions from dynamical properties of unsteady volcanic plume using high-speed imagery and numerical simulations

    NASA Astrophysics Data System (ADS)

    Tournigand, Pierre-Yves; Taddeucci, Jacopo; José Peña Fernandez, Juan; Gaudin, Damien; Sesterhenn, Jörn; Scarlato, Piergiorgio; Del Bello, Elisabetta

    2016-04-01

    Vent conditions are key parameters controlling volcanic plume dynamics and the ensuing different hazards, such as human health issues, infrastructure damages, and air traffic disruption. Indeed, for a given magma and vent geometry, plume development and stability over time mainly depend on the mass eruption rate, function of the velocity and density of the eruptive mixture at the vent, where direct measurements are impossible. High-speed imaging of eruptive plumes and numerical jet simulations were here non-dimensionally coupled to retrieve eruptive vent conditions starting from measurable plume parameters. High-speed videos of unsteady, momentum-driven volcanic plumes (jets) from Strombolian to Vulcanian activity from three different volcanoes (Sakurajima, Japan, Stromboli, Italy, and Fuego, Guatemala) were recorded in the visible and the thermal spectral ranges by using an Optronis CR600x2 (1280x1024 pixels definition, 500 Hz frame rate) and a FLIR SC655 (640x480 pixels definition, 50 Hz frame rate) cameras. Atmospheric effects correction and pre-processing of the thermal videos were performed to increase measurement accuracy. Pre-processing consists of the extraction of the plume temperature gradient over time, combined with a temperature threshold in order to remove the image background. The velocity and the apparent surface temperature fields of the plumes, and their changes over timescales of tenths of seconds, were then measured by particle image velocimetry and thermal image analysis, respectively, of the pre-processed videos. The parameters thus obtained are representative of the outer plume surface, corresponding to its boundary shear layer at the interface with the atmosphere, and may significantly differ from conditions in the plume interior. To retrieve information on the interior of the plume, and possibly extrapolate it even at the eruptive vent level, video-derived plume parameters were non-dimensionally compared to the results of numerical

  8. Bombs, flyin' high. In-flight dynamics of volcanic bombs from Strombolian to Vulcanian eruptions.

    NASA Astrophysics Data System (ADS)

    Taddeucci, Jacopo; Alatorre, Miguel; Cruz Vázquez, Omar; Del Bello, Elisabetta; Ricci, Tullio; Scarlato, Piergiorgio; Palladino, Danilo

    2016-04-01

    Bomb-sized (larger than 64 mm) pyroclasts are a common product of explosive eruptions and a considerable source of hazard, both from directly impacting on people and properties and from wildfires associated with their landing in vegetated areas. The dispersal of bombs is mostly modeled as purely ballistic trajectories controlled by gravity and drag forces associated with still air, and only recently other effects, such as the influence of eruption dynamics, the gas expansion, and in-flight collisions, are starting to be quantified both numerically and observationally. By using high-speed imaging of explosive volcanic eruptions here we attempt to calculate the drag coefficient of free-flying volcanic bombs during an eruption and at the same time we document a wide range of in-flight processes affecting bomb trajectories and introducing deviations from purely ballistic emplacement. High-speed (500 frames per second) videos of explosions at Stromboli and Etna (Italy), Fuego (Gatemala), Sakurajima (Japan), Yasur (Vanuatu), and Batu Tara (Indonesia) volcanoes provide a large assortment of free-flying bombs spanning Strombolian to Vulcanian source eruptions, basaltic to andesitic composition, centimeters to meters in size, and 10 to 300 m/s in fly velocity. By tracking the bombs during their flying trajectories we were able to: 1) measure their size, shape, and vertical component of velocity and related changes over time; and 2) measure the different interactions with the atmosphere and with other bombs. Quantitatively, these data allow us to provide the first direct measurement of the aerodynamic behavior and drag coefficient of volcanic bombs while settling, also including the effect of bomb rotation and changes in bomb shape and frontal section. We also show how our observations have the potential to parameterize a number of previously hypothesized and /or described but yet unquantified processes, including in-flight rotation, deformation, fragmentation, agglutination

  9. Native gold from volcanic gases at Tolbachik 1975-76 and 2012-13 Fissure Eruptions, Kamchatka

    NASA Astrophysics Data System (ADS)

    Chaplygin, Ilya; Yudovskaya, Marina; Vergasova, Lidiya; Mokhov, Andrey

    2015-12-01

    Aggregates and euhedral crystals of native gold were found in sublimates formed during New Tolbachik Fissure Eruption in 2012-2013 (NTFE). Gold-bearing sublimate samples were taken from a red-hot (690 °C) degassing fracture in the roof of an active lava tunnel 1.5 km from active Naboko cinder cone in May 2013. The gas condensate collected at 690 °C in this site contains 16 ppb Au, 190 ppb Ag and 1180 ppm Cu compared to 3 ppb Au, 39 ppb Ag and 9.7 ppm Cu in the condensate of pristine magmatic gas sampled at 1030 °C. The 690 °C volcanic gas is most likely a mix of magmatic gas and local snow buried under the lava flows as indicated by oxygen and hydrogen isotope compositions of the condensate. The lower-temperature gas enrichment in gold, copper and chlorine is resulted from evaporation of the 690 °C condensate during forced gas pumping at sampling. Native gold was also found in fumarolic encrustations collected from caverns in basalt lava flows with temperature up to 600 °C in June 2014, in a year after eruption finished. The native gold precipitation in newly formed Cu-rich sublimates together with the well known gold occurrences in cinder cones of 1975-1976 Large Tolbachik Fissure Eruption manifest a transport capability of oxidized volcanic gas.

  10. The eruption history of the quaternary Eifel volcanic fields: Implications from the ELSA - Tephra - Stack

    NASA Astrophysics Data System (ADS)

    Förster, Michael; Sirocko, Frank

    2015-04-01

    Numerous tephra layers occur in maar sediments in the quaternary Eifel volcanic fields. The sediments were systematically drilled and cored since 1998 by the Eifel Laminated Sediment Archive project (ELSA) (Sirocko et al. 2013). These maar sediments are laminated and the tephra is easily recognizeable by a coarser grain size. Additionaly, tephra layers appear dark grey to black in color. The ashes were sieved to a fraction of 250 - 100 µm and sorted into grains of: reddish and greyish sandstone, quartz, amphibole, pyroxene, scoria and pumice, sanidine, leucite and biotite. A minimum of 100 grains for each tephra layer were used for a sediment petrographic tephra characterisation (SPTC). The grain counts resemble the vol. -% of each grain species. Three types of tephra could be identified by their distinctive grain pattern: (1) phreatomagmatic tephra, rich in basement rocks like greyish/reddish sandstone and quartz. (2) Strombolian tephra, rich in scoria and mafic minerals like pyroxene. (3) evolved tephra, rich in sanidine and pumice. 16 drill-cores, covering the last 500 000 years have been examined. Younger cores were dated by 14C ages and older cores by optical stimulated luminescence. Independently from this datings, the drill-cores were cross-correlated by pollen and the occurences of specific marker-tephra layers, comprising characteristic grain-types. These marker-tephra layers are especially thick and of evolved composition with a significant abundance of sanidine and pumice. The most prominent tephra layers of this type are the Laacher See tephra, dated to 12 900 b2k by Zolitschka (1998), the 40Ar/39Ar dated tephra layers of Dümpelmaar, Glees and Hüttenberg, dated to 116 000 b2k, 151 000 b2k and 215 000 b2k by van den Bogaard & Schmincke (1990), van den Bogaard et al. (1989). These datings set the time-frame for the eruption-phases of the quaternary Eifel Volcanic Fields. Our study refines these findings and shows that phases of activity are very

  11. Uncertainties in Initial Plume Modeling: What is needed prior to a volcanic eruption?

    NASA Astrophysics Data System (ADS)

    Webley, P. W.; Dehn, J.

    2015-12-01

    Low-probability high-intensity volcanic events are likely to have the greatest impact on us all. Pre-event scenario planning can help us to understand the likelihood of event type, size and duration while observational data can be used, once an event occurs, as calibration/validation to the pre-event modeling. During the 2010 Eyjafjallajökull eruption uncertainty in initial plume dynamics and ash mass lead to significant variability in modeling the downwind ash clouds. To forecast the potential dispersal patterns from volcanic eruptions assumptions are made on eruption start time; initial plume dynamics; erupted mass; and erupted/dispersing particle size distributions. There is a need for pre-event inputs to the dispersion models used in operational ash cloud forecasting. There are a number of different initial plume models available and each has its own set of defined inputs that are needed to model the eruption plume. There is a need for updated rapidly produced scenarios daily at time of unrest and updated as soon as the event occurs. While validation with satellite data is key, the models can forecast ash in locations that could be below detection limits that are still relevant for mitigation strategies and aviation safety. So, are we sufficiently prepared to perform the number of initial plume modeling simulations to capture all the potential variability in the dispersion model inputs? Can a systematic approach be developed for application within the operational environment and for use by the volcanic ash advisory centers? Here we will present approaches to building a real-time workflow that encompasses the initial plume uncertainties and discuss how we as a community can develop tools to be implemented in an operational environment. The aim is to a build a complete system to provide the simulations of the ash cloud location and concentrations along with confidence levels that can then be used by the aviation community in their decision support systems.

  12. 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

  13. The influence of tropical volcanic eruptions on the climate of South America during the last millennium

    NASA Astrophysics Data System (ADS)

    Colose, C. M.; LeGrande, A. N.; Vuille, M.

    2015-07-01

    Currently, little is known on how volcanic eruptions impact large-scale climate phenomena such as paleo-ITCZ position or South American summer monsoon behavior. In this paper, an analysis of observations and model simulations is employed to assess the influence of large volcanic eruptions on the climate of South America. This problem is considered both for historically recent volcanic episodes, for which more comprehensive global observations exist, as well as reconstructed volcanic events for the period 850 C.E. to present that are incorporated into the NASA GISS ModelE2-R simulation of the Last Millennium. An advantage of this model is its ability to explicitly track water isotopologues throughout the hydrologic cycle and simulating the isotopic imprint following a large eruption. This effectively removes a degree of uncertainty associated with error-prone conversion of isotopic signals into climate variables, and allows for a direct comparison between GISS simulations and paleoclimate proxy archives. Our analysis reveals that both precipitation and oxygen isotope variability respond with a distinct seasonal and spatial structure across South America following an eruption. During austral winter, the heavy oxygen isotope in precipitation is enriched, likely due to reduced moisture convergence in the ITCZ domain and reduced rainfall over northern South America. During austral summer, however, precipitation is depleted in heavy isotopes over Amazonia, despite reductions in rainfall, suggesting that the isotopic response is not a simple function of the "amount effect". During the South American monsoon season, the amplitude of the temperature response to volcanic forcing is larger than the rather weak and spatially less coherent precipitation signal, potentially masking the isotopic response to changes in the hydrologic cycle.

  14. Constraining explosive volcanism: subjective choices during estimates of eruption magnitude

    USGS Publications Warehouse

    Klawonn, Malin; Houghton, Bruce F.; Swanson, Don; Fagents, Sarah A.; Wessel, Paul; Wolfe, Cecily J.

    2014-01-01

    When estimating the magnitude of explosive eruptions from their deposits, individuals make three sets of critical choices with respect to input data: the spacing of sampling sites, the selection of contour intervals to constrain the field measurements, and the hand contouring of thickness/isomass data, respectively. Volcanologists make subjective calls, as there are no accepted published protocols and few accounts of how these choices will impact estimates of eruption magnitude. Here, for the first time, we took a set of unpublished thickness measurements from the 1959 Kīlauea Iki pyroclastic fall deposit and asked 101 volcanologists worldwide to hand contour the data. First, there were surprisingly consistent volume estimates across maps with three different sampling densities. Second, the variability in volume calculations imparted by individuals’ choices of contours is also surprisingly low and lies between s = 5 and 8 %. Third, volume estimation is insensitive to the extent to which different individuals “smooth” the raw data in constructing contour lines. Finally, large uncertainty is associated with the construction of the thinnest isopachs, which is likely to underestimate the actual trend of deposit thinning. The net result is that researchers can have considerable confidence in using volume or dispersal data from multiple authors and different deposits for comparative studies. These insights should help volcanologists around the world to optimize design and execution of field-based studies to characterize accurately the volume of pyroclastic deposits.

  15. Radiocarbon Dates from Volcanic Deposits of the Chaos Crags and Cinder Cone Eruptive Sequences and Other Deposits, Lassen Volcanic National Park and Vicinity, California

    USGS Publications Warehouse

    Clynne, Michael A.; Christiansen, Robert L.; Trimble, Deborah A.; McGeehin, John P.

    2008-01-01

    This contribution reports radiocarbon ages obtained from charcoal, wood and other samples collected between 1979 and 2001 in Lassen Volcanic National Park and vicinity and a few samples from other nearby localities. Most of the samples are from the Chaos Crags and Cinder Cone eruptive sequences. Brief summaries are given of the Chaos Crags and Cinder Cone eruptive sequences.

  16. Characterization of organic contaminants in environmental samples associated with mount St. Helens 1980 volcanic eruption

    USGS Publications Warehouse

    Pereira, W.E.

    1982-01-01

    Volcanic ash, surface-water, and bottom-material samples obtained in the vicinity of Mount St. Helens after the May 18, 1980, eruption were analyzed for organic contaminants by using capillary gas chromatography-mass spectrometry-computer techniques. Classes of compounds identified include n-alkanes, fatty acids, dicarboxylic acids, aromatic acids and aldehydes, phenols, resin acids, terpenes, and insect juvenile hormones. The most probable source of these compounds is from pyrolysis of plant and soil organic matter during and after the eruption. The toxicity of selected compounds and their environmental significance are discussed.

  17. Possible effects on the stratosphere of the 1963 Mt. Agung volcanic eruption.

    NASA Technical Reports Server (NTRS)

    Mcinturff, R. M.; Miller, A. J.; Angell, J. K.; Korshover , J.

    1971-01-01

    Previous studies of atmospheric pollution resulting from the 1963 eruption of Mt. Agung have shown that the volcanic dust caused temperature increases in the lower stratosphere over Australia. The present study provides time series of monthly-mean lower stratospheric temperatures for eight tropical stations on both sides of the equator. The data have been smoothed by taking 12-month running means. The results suggest that any effect of the eruption may be impossible to isolate. Some features of the quasi-biennial oscillation in zonal winds and temperatures are pointed out which must be considered in any attempt to explain the peculiarities in the curves of monthly mean temperatures.

  18. 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.

  19. 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

  20. 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.

  1. 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

  2. Recent volcanic activity on Venus - Evidence from radiothermal emissivity measurements

    NASA Astrophysics Data System (ADS)

    Robinson, C. A.; Wood, J. A.

    1993-03-01

    Radiothermal emissivity measurements are analyzed in order to study large volcanic constructs on Venus and to correlate details of the reflectivity/emissivity patterns with geological landforms and stratigraphy visible in corresponding SAR images. There appears to be a correlation between locations on Venus where high emissivity at high altitudes and low emissivity at low altitudes are observed. These phenomena are attributed here to relatively recent volcanic activity: the former to summit eruptions that have not had time to weather to the low-emissivity state, the latter to continuing emission of volcanic gases from neighboring small plains volcanoes. The pattern of reflectivity and emissivity on Maat Mons is examined in the light of these findings. It is concluded that Maat Mons has undergone the most recent episode of volcanic activity of all the volcanoes studied here.

  3. Recent volcanic activity on Venus - Evidence from radiothermal emissivity measurements

    NASA Technical Reports Server (NTRS)

    Robinson, Cordula A.; Wood, John A.

    1993-01-01

    Radiothermal emissivity measurements are analyzed in order to study large volcanic constructs on Venus and to correlate details of the reflectivity/emissivity patterns with geological landforms and stratigraphy visible in corresponding SAR images. There appears to be a correlation between locations on Venus where high emissivity at high altitudes and low emissivity at low altitudes are observed. These phenomena are attributed here to relatively recent volcanic activity: the former to summit eruptions that have not had time to weather to the low-emissivity state, the latter to continuing emission of volcanic gases from neighboring small plains volcanoes. The pattern of reflectivity and emissivity on Maat Mons is examined in the light of these findings. It is concluded that Maat Mons has undergone the most recent episode of volcanic activity of all the volcanoes studied here.

  4. Idiosyncrasies of volcanic sulfur viscosity and the triggering of unheralded volcanic eruptions

    NASA Astrophysics Data System (ADS)

    Scolamacchia, Teresa; Cronin, Shane

    2016-03-01

    Unheralded "blue-sky" eruptions from dormant volcanoes cause serious fatalities, such as at Mt. Ontake (Japan) on 27 September 2014. Could these events result from magmatic gas being trapped within hydrothermal system aquifers by elemental sulfur (Se) clogging pores, due to sharp increases in its viscosity when heated above 159oC? This mechanism was thought to prime unheralded eruptions at Mt. Ruapehu in New Zealand. Impurities in sulfur (As, Te, Se) are known to modify S-viscosity and industry experiments showed that organic compounds, H2S, and halogens dramatically influence Se viscosity under typical hydrothermal heating/cooling rates and temperature thresholds. However, the effects of complex sulfur compositions are currently ignored at volcanoes, despite its near ubiquity in long-lived volcano-hydrothermal systems. Models of impure S behavior must be urgently formulated to detect pre-eruptive warning signs before the next "blue-sky" eruption

  5. Reconstruction of eruption column model based on the 3D numerical simulation of volcanic plume for 2011 Shinmoe-dake eruption

    NASA Astrophysics Data System (ADS)

    Hashimoto, A.; Suzuki, Y.; Shimbori, T.; Ishii, K.; Takagi, A.

    2014-12-01

    The result of volcanic ash transport simulation strongly depends on an eruption column model, that gives a profile of discharging rate of ash particles, for a predictability of dispersion of ash particles. Simple eruption column models, such as proposed by Suzuki (1983), have been adopted in volcanic ash transport simulations for its simplicity and convenience. However, such a model sometimes brings erroneous results especially when an environmental wind field considerably affects the behavior of eruption column. The distortion of eruption column and enhancement of turbulent mixing due to wind shear should be taken into account in an eruption column model for the improvement of its applicability. The authors have conducted the three-dimensional simulation of volcanic plume for the 2011 Shinmoe-dake eruption, assuming the vertically-sheared wind field actually observed in the event, and have taken statistics of the locations and mobile vectors of the ash particles getting out of the simulated volcanic plume to establish the profile of discharging rate. The resulted profile is distinctly different from that based on a usual eruption column model. The new profile is characterized by the relatively large discharge of micron-sized ash particles from the middle level of the plume, comparing to the usual one. The authors plan to validate the new model in the simulation of long-range transport of volcanic ash, based on satellite observation data. This work will be a basis for a future improvement of the volcanic ash fall forecast by Japan Meteorological Agency, which is established with the Suzuki's model. The characteristics and validity of new model will be discussed in the presentation. Acknowledgement This study was supported by the Earthquake Research Institute cooperative research program. References Suzuki, T., 1983: A theoretical model for dispersion of tephra. Arc Volcanism: Physics and Tectonics. TERRAPUB, 95-113.

  6. The role of external environmental factors in changing eruption styles of monogenetic volcanoes in a Mio/Pleistocene continental volcanic field in western Hungary

    NASA Astrophysics Data System (ADS)

    Kereszturi, Gábor; Németh, Károly; Csillag, Gábor; Balogh, Kadosa; Kovács, János

    2011-04-01

    The occurrence, shape, structure and eruption style of monogenetic volcanoes, such as maars, tuff rings, tuff cones and scoria cones, are generally governed by several internal (composition of the magma, magmatic flux, ascent rate, viscosity, volatile contents) and external conditions (regional and local tectonics, topography, and the presence of surfacial, ground and meteoric water). These controlling factors are together responsible for the eruption style, distribution pattern, volcanic facies architecture and morphology of the monogenetic volcanic landforms. The Late Miocene to Pleistocene Bakony-Balaton Highland Volcanic Field (BBHVF) in western Hungary is a typical small sized (< 50 eruption centres), basaltic, intraplate "monogenetic" volcanic field. Generally, initial eruptions of the BBHVF were phreatomagmatic (n = ~ 28); however, a lesser number (n = ~ 14) of predominantly scoria cone forming eruptions are also inferred. The temporal distribution of the Strombolian style scoria cones was concentrated mostly between 3 and 2.5 Ma. A detailed study of the changes in eruption styles recorded in the pyroclastic sequences suggested a change from a conventional phreatomagmatic to a magmatic fragmentation style during the activity of the volcanic field. A clear correlation has been identified between the long-term environmental changes of the region that resulted in a gradual shift from a more phreatomagmatic eruption style to a more magmatic eruption style. Detailed examination of the temporal distribution of K-Ar and Ar-Ar radiometric data, Digital Elevation Model and Dense Rock Equivalent-based volume calculations of eruptive products and origin of pyroclastic rocks (e.g. phreatomagmatic or magmatic) preserved in variously eroded monogenetic volcanoes were utilized to integrate available volcanological and climatological data to identify potential links between external and internal controlling parameters that responsible for long-term eruption style changes

  7. Stratified tephra records from lake sediment archives: Holocene eruptions of the Virunga Volcanic Province, East African Rift

    NASA Astrophysics Data System (ADS)

    Lane, Christine; Scholz, Christopher; Poppe, Sam; Schmid, Martin; Ross, Kelly Ann

    2016-04-01

    Lake sediments preserve rare stratified records of explosive volcanism, often with accompanying chronological controls or climatostratigraphic detail. In proximal areas where outcrop stratigraphies are complex, exposures isolated and sediments frequently eroded, the lacustrine archive provides a means to check the order of events and identify additional eruptions not preserved on land. The visible volcanic ash (tephra) record within lake sediments may be limited by eruption volume, distance from source and high sedimentation rates. A more complete eruption history can be detected through the study of non-visible tephra layers. Such "cryptotephra" records may be revealed through non-destructive core-scanning methods, such as XRF-scanning or magnetic susceptibility measurements, or by more thorough laboratory processes and microscopic analysis. Compositional analysis of tephra glass shards using WDS-EPMA and LA-ICP-MS provide a means to provenance eruptions, to cross-correlate between multiple sediment cores, and to establish connections between the lacustrine record and proximal outcrops. Here we present the results of such a "tephrostratigraphic" approach applied to the Holocene volcanic record of the Virunga Volcanic Province (VVP). More than 10 explosive volcanic eruptions, attributed to multiple volcanic centres, are evidenced over the last 12,000 years. This unique insight into the frequency of explosive eruptions from the VVP, demonstrates the potential of visible and cryptotephra investigations in lacustrine sediment archives as a means of studying past, present and future volcanic hazards.

  8. Joint Inversions of Gas Emissions and Ground Deformation During and Following Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Edmonds, M.; McCormick, B. T.

    2015-12-01

    Volcanic eruptions are associated with complex, time-dependent gas emissions and ground deformation. Observations of such signals are a primary gauge of eruption mechanisms, progress and cessation and as such, are critical for hazard assessment. It is often the case that gas emissions and deformation continue for months to years after the end of an eruption. Interpretation of such signals are critical for making decisions about whether an eruption may be considered over or not, yet very little is understood about the processes behind them and how they are coupled. However, the link between the deformation measured and the gases emitted during and after eruptions is fundamental. It has long been recognised that the presence of exsolved fluids enhances magma compressibility, leading to smaller-than-expected syn-eruptive volume changes observed at the surface (by InSAR or by GPS networks). The fluid phase present in the magma prior to eruption contains an assemblage of volatile species, most of which we are able to measure at the surface. Our improved understanding of volatile saturation in silicate melts and the availability of thermodynamic models to predict the partitioning of sulfur between fluid and melt means that coupled interpretations of gas emissions and deformation are now possible, given independent estimates of erupted volumes and other intrinsic parameters such as pressure, temperature and oxygen fugacity. We illustrate, using a well constrained example of a prolonged, multi-episode eruption, the utility in developing coupled models to describe volume changes and outgassing processes with a view to enhancing our ability to interpret these critical monitoring data streams.

  9. Immediate public health concerns and actions in volcanic eruptions: lessons from the Mount St. Helens eruptions, May 18-October 18, 1980.

    PubMed Central

    Bernstein, R S; Baxter, P J; Falk, H; Ing, R; Foster, L; Frost, F

    1986-01-01

    A comprehensive epidemiological evaluation of mortality and short-term morbidity associated with explosive volcanic activity was carried out by the Centers for Disease Control in collaboration with affected state and local health departments, clinicians, and private institutions. Following the May 18, 1980 eruption of Mount St. Helens, a series of public health actions were rapidly instituted to develop accurate information about volcanic hazards and to recommend methods for prevention or control of adverse effects on safety and health. These public health actions included: establishing a system of active surveillance of cause-specific emergency room (ER) visits and hospital admissions in affected and unaffected communities for comparison; assessing the causes of death and factors associated with survival or death among persons located near the crater; analyzing the mineralogy and toxicology of sedimented ash and the airborne concentration of resuspended dusts; investigating reported excesses of ash-related adverse respiratory effects by epidemiological methods such as cross-sectional and case-control studies; and controlling rumors and disseminating accurate, timely information about volcanic hazards and recommended preventive or control measures by means of press briefings and health bulletins. Surveillance and observational studies indicated that: excess in morbidity were limited to transient increases in ER visits and hospital admissions for traumatic injuries and respiratory problems (but not for communicable disease or mental health problems) which were associated in time, place, and person with exposures to volcanic ash; excessive mortality due to suffocation (76 per cent), thermal injuries (12 per cent), or trauma (12 per cent) by ash and other volcanic hazards was directly proportional to the degree of environmental damage--that is, it was more pronounced among those persons (48/65, or about 74 per cent) who, at the time of the eruption, were residing

  10. Volcanic eruptions: atmospheric effects. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-04-01

    The bibliography contains citations concerning gaseous and particulate contributions to the Earth's atmosphere from volcanoes, and the effects these substances have on the climate and the environment. Case studies of specific volcanic eruptions; detection and measurement of volcanic gases, aerosols, and particulates in the atmosphere; environmental effects on the biota; long and short term climatological effects; paleoclimatology and volcanoes; atmospheric and transport modelling; and solar radiation inhibition are among the topics discussed. (Contains a minimum of 179 citations and includes a subject term index and title list.)

  11. Solar Eruptions Initiated in Sigmoidal Active Regions

    NASA Astrophysics Data System (ADS)

    Savcheva, Antonia

    2016-07-01

    active regions that have been shown to possess high probability for eruption. They present a direct evidence of the existence of flux ropes in the corona prior to the impulsive phase of eruptions. In order to gain insight into their eruptive behavior and how they get destabilized we need to know their 3D magnetic field structure. First, we review some recent observations and modeling of sigmoidal active regions as the primary hosts of solar eruptions, which can also be used as useful laboratories for studying these phenomena. Then, we concentrate on the analysis of observations and highly data-constrained non-linear force-free field (NLFFF) models over the lifetime of several sigmoidal active regions, where we have captured their magnetic field structure around the times of major flares. We present the topology analysis of a couple of sigmoidal regions pointing us to the probable sites of reconnection. A scenario for eruption is put forward by this analysis. We demonstrate the use of this topology analysis to reconcile the observed eruption features with the standard flare model. Finally, we show a glimpse of how such a NLFFF model of an erupting region can be used to initiate a CME in a global MHD code in an unprecedented realistic manner. Such simulations can show the effects of solar transients on the near-Earth environment and solar system space weather.

  12. Observations of volcanic tremor during January-February 2005 eruption of Mt. Veniaminof, Alaska

    USGS Publications Warehouse

    De Angelis, Slivio; McNutt, Stephen R.

    2007-01-01

    Mt. Veniaminof, Alaska Peninsula, is a stratovolcano with a summit ice-filled caldera containing a small intracaldera cone and active vent. From January 2 to February 21, 2005, Mt. Veniaminof erupted. The eruption was characterized by numerous small ash emissions (VEI 0 to 1) and accompanied by low-frequency earthquake activity and volcanic tremor. We have performed spectral analyses of the seismic signals in order to characterize them and to constrain their source. Continuous tremor has durations of minutes to hours with dominant energy in the band 0.5– 4.0 Hz, and spectra characterized by narrow peaks either irregularly (non-harmonic tremor) or regularly spaced (harmonic tremor). The spectra of non-harmonic tremor resemble those of low-frequency events recorded simultaneously with surface ash explosions, suggesting that the source mechanisms might be similar or related. We propose that non-harmonic tremor at Mt. Veniaminof results from the coalescence of gas bubbles while low-frequency events are related to the disruption of large gas pockets within the conduit. Harmonic tremor, characterized by regular and quasisinusoidal waveforms, has duration of hours. Spectra containing up to five harmonics suggest the presence of a resonating source volume that vibrates in a longitudinal acoustic mode. An interesting feature of harmonic tremor is that frequency is observed to change over time; spectral lines move towards higher or lower values while the harmonic nature of the spectra is maintained. Factors controlling the variable characteristics of harmonic tremor include changes in acoustic velocity at the source and variations of the effective size of the resonator.

  13. Prolonged eruptive history of a compound volcano on Mercury: Volcanic and tectonic implications

    NASA Astrophysics Data System (ADS)

    Rothery, David A.; Thomas, Rebecca J.; Kerber, Laura

    2014-01-01

    A 27×13 km ‘rimless depression’ 100 km inside the southwest rim of the Caloris basin is revealed by high resolution orbital imaging under a variety of illuminations to consist of at least nine overlapping volcanic vents, each individually up to 8 km in diameter. It is thus a ‘compound’ volcano, indicative of localised migration of the site of the active vent. The vent floors are at a least 1 km below their brinks, but lack the flat shape characteristically produced by piston-like subsidence of a caldera floor or by flooding of a crater bottom by a lava lake. They bear a closer resemblance to volcanic craters sculpted by explosive eruptions and/or modified by collapse into void spaces created by magma withdrawal back down into a conduit. This complex of overlapping vents is at the summit of a subtle edifice at least 100 km across, with flank slopes of about only 0.2 degrees, after correction for the regional slope. This is consistent with previous interpretation as a locus of pyroclastic eruptions. Construction of the edifice could have been contributed to by effusion of very low viscosity lava, but high resolution images show that the vent-facing rim of a nearby impact crater is not heavily embayed as previously supposed on the basis of lower resolution flyby imaging. Contrasts in morphology (sharpness versus blurredness of the texture) and different densities of superposed sub-km impact craters inside each vent are consistent with (but do not prove) substantial differences in the age of the most recent activity at each vent. This suggests a long duration of episodic magmagenesis at a restricted locus. The age range cannot be quantified, but could be of the order of a billion years. If each vent was fed from the same point source, geometric considerations suggest a source depth of at least 50 km. However, the migration of the active vent may be partly controlled by a deep-seated fault that is radial to the Caloris basin. Other rimless depressions in this

  14. Prolonged eruptive history of a compound volcano on Mercury: volcanic and tectonic implications

    NASA Astrophysics Data System (ADS)

    Rothery, D. A.; . T. Thomas, R.; Kerber, L.

    2013-09-01

    High resolution orbital imaging by MESSENGER under a variety of illuminations reveals that a 27 × 13 km rimless depression 100 km inside the southwest rim of the Caloris basin consists of at least nine overlapping volcanic vents, each individually up to 8 km in diameter. This is thus a 'compound' volcano, indicative of localised migration of the site of the active vent. The vent floors are at a least 1 km below their brinks, but lack the flat shape that is characteristically produced by piston-like subsidence of a caldera floor or by flooding of a crater bottom by a lava lake. They bear a closer resemblance to volcanic craters sculpted by explosive eruptions and/or modified by collapse into void spaces created by magma withdrawal back down into a conduit. This complex of overlapping vents is at the summit of a subtle edifice at least 100 km across, with flank slopes of about 0.2 degrees, after correction for the regional slope. This is consistent with previous interpretation as a locus of pyroclastic eruptions. Construction of the edifice could have been contributed to by effusion of very low viscosity lava, but high resolution images show that the vent-facing rim of a nearby impact crater is not heavily embayed as previously supposed. Contrasts in morphology (sharpness versus blurredness of the texture) and different densities of superposed sub-km impact craters inside each vent suggest significant differences in the age of the most recent activity at each vent. This implies a long duration of episodic magmagenesis at a restricted locus. The age range is hard to quantify, but could be of the order of a billion years. If each vent was fed from the same source, geometric considerations suggest a source depth of at least 50 km. The migration of the active vent may be partly controlled by a deep-seated fault that is radial to the Caloris basin. Other rimless depressions in this part of the Caloris basin fall on or close to radial lines, suggesting that elements of

  15. The Influence of a Fluctuating Mass Flux on the Development and Rise of Volcanic Eruption Clouds

    NASA Astrophysics Data System (ADS)

    Scharff, L.; Hort, M. K.; Herzog, M.; Esposti Ongaro, T.

    2013-12-01

    Eruption clouds are a major hazard to aviation. Hence real-time tracking and forecasting of ash clouds are increasingly important tasks in volcanology. In-situ measurements of the dynamics inside the developing cloud are needed as constraint to the input parameters of the VAAC's numerical ash cloud dispersion models. The Doppler radar technique provides particle velocities and a proxy of the near-vent mass flux, and has been used in two field experiments at Santiaguito volcano (Guatemala) and Volcán de Colima (Mexico) to constrain the near-vent dynamics of Vulcanian events. The two Doppler radar datasets show that fluctuating (or pulsed, non-continuous) mass flux occurs at both volcanoes Santiaguito and Colima. Pulses have also been observed at other volcanoes (e.g. Stromboli, Italy, and Arenal volcano, Costa Rica) and may be a more common feature than previously assumed. Using (1) the 'active tracer high-resolution atmospheric model' (ATHAM) and (2) a multi-phase fluid dynamics model for dispersion of volcanic ash (PDAC), we model the first 400 m of eruption cloud formation. For a comparison with the measured Doppler radar data, synthetic Doppler data are calculated from the numerical model results by converting particle properties (size, velocity, and backscatter-efficiency) into synthetic velocity spectra. The two-dimensional axis-symmetric simulations show that the Doppler radar data can visually be classified into jet-dominated and buoyancy-dominated regimes and that pulses are local phenomena and can only be observed in the jet region of the cloud. The Colima Doppler radar dataset shows that a fluctuating mass flux can even be observed a few hundred meters above the vent if a direct measurement of the dynamics at the vent is not possible. Our portable Doppler radar needs to be installed within a 6 km radius to the vent and can only observe one vent at a time. Weather radars are able to observe several volcanoes simultaneously. However, they mainly observe

  16. 2007 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory

    USGS Publications Warehouse

    McGimsey, Robert G.; Neal, Christina A.; Dixon, James P.; Malik, Nataliya; Chibisova, Marina

    2011-01-01

    The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2007. The year was highlighted by the eruption of Pavlof, one of Alaska's most frequently active volcanoes. Glaciated Fourpeaked Mountain, a volcano thought to have been inactive in the Holocene, produced a phreatic eruption in the autumn of 2006 and continued to emit copious amounts of steam and volcanic gas into 2007. Redoubt Volcano showed the first signs of the unrest that would unfold in 2008-09. AVO staff also participated in hazard communication and monitoring of multiple eruptions at seven volcanoes in Russia as part of its collaborative role in the Kamchatka and Sakhalin Volcanic Eruption Response Teams.

  17. Wendo Koshe Pumice: The latest Holocene silicic explosive eruption product of the Corbetti Volcanic System (Southern Ethiopia)

    NASA Astrophysics Data System (ADS)

    Rapprich, Vladislav; Žáček, Vladimír; Verner, Kryštof; Erban, Vojtěch; Goslar, Tomasz; Bekele, Yewubinesh; Legesa, Firdawok; Hroch, Tomáš; Hejtmánková, Petra

    2016-01-01

    The Plinian eruption of the Wendo Koshe crater within the Corbetti Caldera occurred around 396 BC. The pumice lapilli deposit, with a thickness exceeding 10 cm, dispersed over an area of over 1000 km2 around the towns of Hawasa and Shashemene. Most of the pumice was deposited by fall-out; however, minor local pyroclastic density currents also occurred. The calculated volume of preserved pumice fall deposit (approximately 1.2 km3), combined with the estimated volume of dispersed fine ash distributed further from the volcano, corresponds to an estimated volume of 0.4 km3 (dense rock equivalent) of erupted magma. The age of the pumice eruption (396 ± 38 BC) was determined by 14C radiometric dating of a paleosoil that developed on previous pyroclastic deposits buried by the pumice. The majority of the post-caldera volcanic products are characterized by a relatively uniform chemical composition (TiO2 = 0.24-0.27 wt.%, Zr = 1300-1600 ppm, ƩREE = 920-1150 ppm) without any significant development in composition. Despite the negligible variations in composition of the magmas that erupted during the last 2500 years within the Corbetti Volcanic System, a significant change in composition was documented prior to the 396 BC Wendo Koshe younger pumice eruption. The caldera stage ignimbrite of Corbetti (TiO2 = 0.34 wt.%, Zr = 500 ppm, ƩREE = 370 ppm) and the early post-caldera obsidians are (TiO2 = 0.34 wt.%, Zr = 800 ppm, ƩREE = 410 ppm) characterized by a commenditic composition, and the character of the rhyolitic magmas shifted towards pantellerites in the post-caldera stage. The compositional contrast is confirmed also by Sr isotope ratios. The Corbetti ignimbrite is characterized by being more radiogenic (87Sr/86Sr = 0.70678) than the post-caldera obsidians (87Sr/86Sr = 0.7046-0.7047). In contrast to the trace-element concentrations, the early Chabi obsidian does not differ from younger obsidians in isotope composition. Similarly to other silicic volcanic systems of the

  18. Global link between deformation and volcanic eruption quantified by satellite imagery

    PubMed Central

    Biggs, J.; Ebmeier, S. K.; Aspinall, W. P.; Lu, Z.; Pritchard, M. E.; Sparks, R. S. J.; Mather, T. A.

    2014-01-01

    A key challenge for volcanological science and hazard management is that few of the world’s volcanoes are effectively monitored. Satellite imagery covers volcanoes globally throughout their eruptive cycles, independent of ground-based monitoring, providing a multidecadal archive suitable for probabilistic analysis linking deformation with eruption. Here we show that, of the 198 volcanoes systematically observed for the past 18 years, 54 deformed, of which 25 also erupted. For assessing eruption potential, this high proportion of deforming volcanoes that also erupted (46%), together with the proportion of non-deforming volcanoes that did not erupt (94%), jointly represent indicators with ‘strong’ evidential worth. Using a larger catalogue of 540 volcanoes observed for 3 years, we demonstrate how this eruption–deformation relationship is influenced by tectonic, petrological and volcanic factors. Satellite technology is rapidly evolving and routine monitoring of the deformation status of all volcanoes from space is anticipated, meaning probabilistic approaches will increasingly inform hazard decisions and strategic development. PMID:24699342

  19. Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Fuglestvedt, J.; Shine, K. P.

    2014-12-01

    A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. How could global society prepare for, and react to, such emergencies? One possibility is deliberate, coordinated emissions of short-lived greenhouse gases, along a pathway designed to match the climate responses to the eruption. We estimate such an emission pathway, countering a hypothetical eruption three times the size of Mt Pinatubo in 1991. Using a global climate model to evaluate global and regional responses to the eruption, with and without counter emissions, we show that it may be possible to counteract its climate effects, significantly dampening the abrupt impact of the eruption. We then raise practical, financial and ethical aspects related to such a strategy. Designed emissions to counter temporary global cooling would not have the disadvantages associated with more commonly discussed geoengineering to avoid long-term warming. Nevertheless, implementation would still face significant challenges.

  20. Radiative effects of the El Chichon volcanic eruption. Preliminary results concerning remote sensing

    NASA Technical Reports Server (NTRS)

    Bandeen, W. R.; Fraser, R. S.

    1982-01-01

    The aerosols and gases resulting from the El Chichon volcanic eruption had, and may still have, significant effects on satellite measurements of the properties of the Earth's atmosphere. The sea surface temperature measured by the AVHRR was biased up to -2.5 C for many months. The total amount of ozone derived from TOMS with a standard algorithm was greatly in excess of the possible value. This apparent excess can now be explained in terms of additional absorption by SO2. Infrared temperature sounders have observed both positive and negative anomalies. These effects and others on many satellite measurements are addressed following a discussion of the history and composition of the ejecta remaining in the stratosphere. Finally, recommendations are made for further study to account for the effects of volcanic eruptions on satellite observations and for use of such observations to measure the characteristics of the ejecta.

  1. 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.

  2. 3D numerical simulations of volcanic plume and tephra dispersal: Reconstruction of the 2014 Kelud eruption

    NASA Astrophysics Data System (ADS)

    Suzuki, Y.; Iguchi, M.; Maeno, F.; Nakada, S.; Hashimoto, A.; Shimbori, T.; Ishii, K.

    2014-12-01

    The heights and expansion rate of eruption cloud and the dispersal pattern of tephra particles are key observable data for understanding the dynamics of volcanic plume. In general, when the volcanic plume rises in a stationary environment, the plume height and expansion rate of the umbrella cloud increases as the eruption intensity (i.e., the magma discharge rate) increases. On the other hand, when the plume is distorted by the atmospheric wind, it is difficult to quantify the relationship between the eruption conditions and the observable data. Therefore, we aim to develop a three-dimensional numerical model of volcanic plume and directly reproduce the plume dynamics and the tephra dispersal. We performed a numerical simulation of the 2014 eruption at Mount Kelud, Java, Indonesia, which formed a large volcanic plume and umbrella cloud in the wind field. We employ a 3D numerical model which is designed to simulate the injection of tephra particles and volcanic gas from a circular vent into the stratified atmosphere, using a combination of a pseudo-gas model for fluid motion and a Lagrangian model for particle motion (Suzuki and Koyaguchi, 2013 EPS). Using the estimated total mass (3.9—6.4×1011 kg) and the eruption duration (2.5 - 3 hours), the average mass discharge rate is estimated to be 3.6—7.1×107 kg/s. In this study, the magma discharge rate is set to be 5×107 kg/s. The weather data based on the radiosonde observation in Surabaya is applied to the atmospheric condition. The simulation results indicate that the top of plume reaches to nearly 30 km and the umbrella cloud radially spreads at the height of 17—20 km high. These simulated heights are consistent with the observations (e.g., NASA Earth Observatory). The particles are transported by the gravity current of the umbrella cloud. Between the umbrella cloud and the ground, the particles separated from the cloud are drifted by the easterly wind. Therefore, the dispersal axis of the main fall deposits

  3. Detection of volcanic sulfate aerosol with Envisat MIPAS shown for the Kasatochi, Sarychev, and Nabro eruptions

    NASA Astrophysics Data System (ADS)

    Griessbach, Sabine; Hoffmann, Lars; Spang, Reinhold; von Hobe, Marc; Müller, Rolf; Riese, Martin

    2013-04-01

    Stratospheric sulfate aerosol is known to have a strong impact on climate. Transport pathways of sulfur dioxide and sulfate aerosol to the stratosphere are still discussed. It is known that volcanic eruptions can inject significant amounts of sulfur directly into the stratosphere. Most sulfur, however, is injected into the troposphere and only a fraction of it can make its way into the stratosphere. Global and altitude resolved time series of observations are a valuable source of information for sulfur dioxide and sulfate aerosol detection. Here we present a new aerosol detection method for the infrared limb sounder Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) and the results for the Kasatochi, Sarychev, and Nabro eruptions. The new detection method utilizes three infrared window regions that are located around 830, 960, and 1224 cm-1. The combination of these three windows allows for a better detection of enhanced aerosol events in the troposphere as well as the discrimination from ice clouds. With this new method the 10 year record of MIPAS measurements was analyzed. The most remarkable sulfate aerosol events follow the Kasatochi, Sarychev, and Nabro eruptions. After these eruptions enhanced aerosol is detected in the upper troposphere and lower stratosphere (UTLS) region. Within one to two months it spreads over most of the northern hemisphere. In the tropics the aerosol reaches altitudes up to around 20 km and in the Arctic up to 15 km. The enhanced aerosol signal can be observed for about 5, 7, and up to 10 month for the Kasatochi, Sarychev, and Nabro eruptions, respectively. During this period the enhanced aerosol detections decrease in number, strength, and observation altitude. After the Nabro eruption on 13 June 2011 volcanic aerosol is detected in the UTLS region two days after the initial eruption. The following days the aerosol moves around the northern edge of the Asian monsoon region, is then transported southwards and later

  4. Revisiting the Atmospheric Rise Heights of Volcanic Eruption Plumes on Mars

    NASA Astrophysics Data System (ADS)

    Meyer, A.; Van Eaton, A. R.; Mastin, L. G.; Clarke, A. B.

    2015-12-01

    Amanda Meyer, Alexa R. Van Eaton, Larry G. Mastin, Amanda B. Clarke Evidence for both effusive and explosive volcanism in the geological record of Mars has highlighted questions about the behavior of eruption plumes in the Martian atmosphere. How does the atmospheric structure of Mars (with surface pressures <1% and gravity <40% that of Earth) affect the rise height of volcanic ash and climate-forcing gases? Early modeling studies suggested that Martian plumes may rise significantly higher than their terrestrial equivalents (Wilson and Head, 1994, Rev. Geophys., 32, 221-263), but the validity of these models was called into question by Glaze and Baloga (2002, JGR, 107, 5086). Here we reevaluate the limitations of plume rise models using a steady-state 1-D model for volcanic plumes (Plumeria: Mastin, 2014, JGR, doi:10.1002/2013JD020604). We have used Plumeria to simulate plume heights using a range of atmospheric profiles representing both modern and 'early' Mars, and a range of volcanic eruption rates from 1 x 103 to 1 x 1010 kg s-1. The model assumes perfect coupling of particles with the gas phase in the plume (pseudogas assumption), and Stokes number analysis indicates that this is a reasonable assumption for particle diameters less than 5 mm to 1 micron, depending on the eruption rate. Our estimates of local Knudsen numbers support the continuum assumption for this model. Therefore, we suggest that even simplified fluid dynamics models may provide first-order insights into the rise of volcanic gases - and to some extent, fine ash particles - on Mars. Our results show that volcanic plumes in a modern Martian atmosphere may rise three times higher than those from equivalent eruption rates on Earth, potentially reaching 120 km above the surface. We provide a series of new theoretical eruption rate-plume height scaling relationships that may be useful for considering plume injection heights, climate impacts and global-scale ash dispersal patterns (e.g., Kerber et

  5. A 36,000-Year-Old Volcanic Eruption Depicted in the Chauvet-Pont d'Arc Cave (Ardèche, France)?

    PubMed

    Nomade, Sébastien; Genty, Dominique; Sasco, Romain; Scao, Vincent; Féruglio, Valérie; Baffier, Dominique; Guillou, Hervé; Bourdier, Camille; Valladas, Hélène; Reigner, Edouard; Debard, Evelyne; Pastre, Jean-François; Geneste, Jean-Michel

    2016-01-01

    Among the paintings and engravings found in the Chauvet-Pont d'Arc cave (Ardèche, France), several peculiar spray-shape signs have been previously described in the Megaloceros Gallery. Here we document the occurrence of strombolian volcanic activity located 35 km northwest of the cave, and visible from the hills above the cave entrance. The volcanic eruptions were dated, using 40Ar/39Ar, between 29 ± 10 ka and 35 ± 8 ka (2σ), which overlaps with the 14C AMS and thermoluminescence ages of the first Aurignacian occupations of the cave in the Megaloceros Gallery. Our work provides the first evidence of an intense volcanic activity between 40 and 30 ka in the Bas-Vivarais region, and it is very likely that Humans living in the Ardèche river area witnessed one or several eruptions. We propose that the spray-shape signs found in the Chauvet-Pont d'Arc cave could be the oldest known depiction of a volcanic eruption, predating by more than 34 ka the description by Pliny the Younger of the Vesuvius eruption (AD 79) and by 28 ka the Çatalhöyük mural discovered in central Turkey.

  6. A 36,000-Year-Old Volcanic Eruption Depicted in the Chauvet-Pont d'Arc Cave (Ardèche, France)?

    PubMed

    Nomade, Sébastien; Genty, Dominique; Sasco, Romain; Scao, Vincent; Féruglio, Valérie; Baffier, Dominique; Guillou, Hervé; Bourdier, Camille; Valladas, Hélène; Reigner, Edouard; Debard, Evelyne; Pastre, Jean-François; Geneste, Jean-Michel

    2016-01-01

    Among the paintings and engravings found in the Chauvet-Pont d'Arc cave (Ardèche, France), several peculiar spray-shape signs have been previously described in the Megaloceros Gallery. Here we document the occurrence of strombolian volcanic activity located 35 km northwest of the cave, and visible from the hills above the cave entrance. The volcanic eruptions were dated, using 40Ar/39Ar, between 29 ± 10 ka and 35 ± 8 ka (2σ), which overlaps with the 14C AMS and thermoluminescence ages of the first Aurignacian occupations of the cave in the Megaloceros Gallery. Our work provides the first evidence of an intense volcanic activity between 40 and 30 ka in the Bas-Vivarais region, and it is very likely that Humans living in the Ardèche river area witnessed one or several eruptions. We propose that the spray-shape signs found in the Chauvet-Pont d'Arc cave could be the oldest known depiction of a volcanic eruption, predating by more than 34 ka the description by Pliny the Younger of the Vesuvius eruption (AD 79) and by 28 ka the Çatalhöyük mural discovered in central Turkey. PMID:26745626

  7. A 36,000-Year-Old Volcanic Eruption Depicted in the Chauvet-Pont d’Arc Cave (Ardèche, France)?

    PubMed Central

    Nomade, Sébastien; Genty, Dominique; Sasco, Romain; Scao, Vincent; Féruglio, Valérie; Baffier, Dominique; Guillou, Hervé; Bourdier, Camille; Valladas, Hélène; Reigner, Edouard; Debard, Evelyne; Pastre, Jean–François; Geneste, Jean-Michel

    2016-01-01

    Among the paintings and engravings found in the Chauvet-Pont d’Arc cave (Ardèche, France), several peculiar spray-shape signs have been previously described in the Megaloceros Gallery. Here we document the occurrence of strombolian volcanic activity located 35 km northwest of the cave, and visible from the hills above the cave entrance. The volcanic eruptions were dated, using 40Ar/39Ar, between 29 ± 10 ka and 35 ± 8 ka (2σ), which overlaps with the 14C AMS and thermoluminescence ages of the first Aurignacian occupations of the cave in the Megaloceros Gallery. Our work provides the first evidence of an intense volcanic activity between 40 and 30 ka in the Bas-Vivarais region, and it is very likely that Humans living in the Ardèche river area witnessed one or several eruptions. We propose that the spray-shape signs found in the Chauvet-Pont d’Arc cave could be the oldest known depiction of a volcanic eruption, predating by more than 34 ka the description by Pliny the Younger of the Vesuvius eruption (AD 79) and by 28 ka the Çatalhöyük mural discovered in central Turkey. PMID:26745626

  8. Global temperature response to the major volcanic eruptions in multiple reanalysis data sets

    NASA Astrophysics Data System (ADS)

    Fujiwara, M.; Hibino, T.; Mehta, S. K.; Gray, L.; Mitchell, D.; Anstey, J.

    2015-12-01

    The global temperature responses to the eruptions of Mount Agung in 1963, El Chichón in 1982, and Mount Pinatubo in 1991 are investigated using nine currently available reanalysis data sets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979-2009 (for eight reanalysis data sets) and 1958-2001 (for four reanalysis data sets), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately, and common and different responses among the older and newer reanalysis data sets are highlighted for each eruption. In response to the Mount Pinatubo eruption, most reanalysis data sets show strong warming signals (up to 2-3 K for 1-year average) in the tropical lower stratosphere and weak cooling signals (down to -1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. Comparison of the results from several different reanalysis data sets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis data sets. The consistencies and differences among different reanalysis data sets provide a measure of the confidence and uncertainty in our current understanding of the volcanic response. The results of this intercomparison study may be useful for validation of climate model responses to volcanic forcing and for assessing proposed geoengineering by stratospheric

  9. Seismic activity before and after the eruption of Kuchinoerabujima in 2015

    NASA Astrophysics Data System (ADS)

    Chiba, K.

    2015-12-01

    Shindake, on Kuchinoerabujima, in the Ryukyu Islands, south of Kyusyu, Japan, erupted at 09:59 JST on 29 May 2015. This eruption is considered to have been a phreato-magmatic eruption, according to the Coordinating Committee for Prediction of Volcanic Eruption in Japan. As characteristic seismic activities before and after the eruption, an A-type event (Mw 2.3) occurred in the northwestern part of Shindake on 23 May, and numerous volcanic events occurred in and around Shindake just after the eruption. The frequency-magnitude distribution (b-value) of earthquakes is commonly high in volcanic areas. It is also known that high b-values in volcanic areas are primarily responsible for material heterogeneity, low shear strength, and high thermal gradients. These facts suggest that the b-value distribution can be used as a tool to locate active magma chambers. It is thus important to determine the distribution of hypocenters precisely and to investigate the b-value distribution on Kuchinoerabujima. We used a data set of the Japan Meteorological Agency and the National Research Institute for Earth Science and Disaster Prevention, and a half-space with Vp = 2.5 km/s as a velocity structure. For the determination of hypocenters, we used the hypomh (Hirata and Matsu'ura 1987) and hypoDD (Waldhauser and Ellsworth 2000) algorithms. This revealed that many estimated hypocenters were distributed in and around the vent at a depth of ~5 km under Shindake before and after the eruption. A volume of high b (>1.2) was locally observed in the eastern part at depths of 1.0-2.5 km below Shindake before the eruption and another was widely observed at depths of 2.0-4.0 km after the eruption. By comparing these findings with other observation results, we may be able to obtain a clear image of the active magma chamber.

  10. Segmentation and Tracking of Anticyclonic Eddies during a Submarine Volcanic Eruption Using Ocean Colour Imagery

    PubMed Central

    Marcello, Javier; Eugenio, Francisco; Estrada-Allis, Sheila; Sangrà, Pablo

    2015-01-01

    The eruptive phase of a submarine volcano located 2 km away from the southern coast of El Hierro Island started on October 2011. This extraordinary event provoked a dramatic perturbation of the water column. In order to understand and quantify the environmental impacts caused, a regular multidisciplinary monitoring was carried out using remote sensing sensors. In this context, we performed the systematic processing of every MODIS and MERIS and selected high resolution Worldview-2 imagery to provide information on the concentration of a number of biological, physical and chemical parameters. On the other hand, the eruption provided an exceptional source of tracer that allowed the study a variety of oceanographic structures. Specifically, the Canary Islands belong to a very active zone of long-lived eddies. Such structures are usually monitored using sea level anomaly fields. However these products have coarse spatial resolution and they are not suitable to perform submesoscale studies. Thanks to the volcanic tracer, detailed studies were undertaken with ocean colour imagery allowing, using the diffuse attenuation coefficient, to monitor the process of filamentation and axisymmetrization predicted by theoretical studies and numerical modelling. In our work, a novel 2-step segmentation methodology has been developed. The approach incorporates different segmentation algorithms and region growing techniques. In particular, the first step obtains an initial eddy segmentation using thresholding or clustering methods and, next, the fine detail is achieved by the iterative identification of the points to grow and the subsequent application of watershed or thresholding strategies. The methodology has demonstrated an excellent performance and robustness and it has proven to properly capture the eddy and its filaments. PMID:25875193

  11. Segmentation and tracking of anticyclonic eddies during a submarine volcanic eruption using ocean colour imagery.

    PubMed

    Marcello, Javier; Eugenio, Francisco; Estrada-Allis, Sheila; Sangrà, Pablo

    2015-01-01

    The eruptive phase of a submarine volcano located 2 km away from the southern coast of El Hierro Island started on October 2011. This extraordinary event provoked a dramatic perturbation of the water column. In order to understand and quantify the environmental impacts caused, a regular multidisciplinary monitoring was carried out using remote sensing sensors. In this context, we performed the systematic processing of every MODIS and MERIS and selected high resolution Worldview-2 imagery to provide information on the concentration of a number of biological, physical and chemical parameters. On the other hand, the eruption provided an exceptional source of tracer that allowed the study a variety of oceanographic structures. Specifically, the Canary Islands belong to a very active zone of long-lived eddies. Such structures are usually monitored using sea level anomaly fields. However these products have coarse spatial resolution and they are not suitable to perform submesoscale studies. Thanks to the volcanic tracer, detailed studies were undertaken with ocean colour imagery allowing, using the diffuse attenuation coefficient, to monitor the process of filamentation and axisymmetrization predicted by theoretical studies and numerical modelling. In our work, a novel 2-step segmentation methodology has been developed. The approach incorporates different segmentation algorithms and region growing techniques. In particular, the first step obtains an initial eddy segmentation using thresholding or clustering methods and, next, the fine detail is achieved by the iterative identification of the points to grow and the subsequent application of watershed or thresholding strategies. The methodology has demonstrated an excellent performance and robustness and it has proven to properly capture the eddy and its filaments. PMID:25875193

  12. Volcanic lightning as a source of reactive radical species in eruption plumes

    NASA Astrophysics Data System (ADS)

    Martin, R. S.; Ilyinskaya, E.

    2011-03-01

    Volcanic lightning has accompanied most recent major explosive eruptions and provides a source of intense thermal energy to drive the formation of reactive radical species. These radicals may have an impact upon the chemical evolution of the eruption plume and its interaction with the atmosphere. Equilibrium modeling shows that within each lightning channel >1% of total N, O, and F and ˜100% of H, Cl, Br, and I may remain as radicals after quenching. The production of radicals generally increases with the quenching temperature of the gas mixture and the dilution of the eruption plume and decreases with increasing atmospheric pressure. Despite the small volume fraction of the plume directly exposed to volcanic lightning (i.e., <10-4), the production of O, H, F, and NO is predicted to be quantitatively significant over the entire plume. Furthermore, these radicals may indirectly lead to the production of Br, Cl, HO2, and O3 through reactions occurring at low temperature. We suggest that