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Sample records for eruptive prominence evidence

  1. Multispacecraft observations of a prominence eruption

    Directory of Open Access Journals (Sweden)

    A. Bemporad

    2009-10-01

    Full Text Available On 9 May 2007 a prominence eruption occurred at the West limb. Remarkably, the event was observed by the STEREO/EUVI telescopes and by the HINODE/EIS and SOHO/UVCS spectrometers. We present results from all these instruments. High-cadence (~37 s data from STEREO/EUVI A and B in the He II λ304 line were used to study the 3-D shape and expansion of the prominence. The high spatial resolution EUVI images (~1.5"/pixel have been used to infer via triangulation the 3-D shape and orientation of the prominence 12 min after the eruption onset. At this time the prominence has mainly the shape of a "hook" highly inclined southward, has an average thickness of 0.068 R⊙, a length of 0.43 R⊙ and lies, in first approximation, on a plane. Hence, the prominence is mainly a 2-D structure and there is no evidence for a twisted flux rope configuration. HINODE/EIS was scanning with the 2" slit the region where the filament erupted. The EIS spectra show during the eruption remarkable non-thermal broadening (up to ~100 km s−1 in the region crossed by the filament in spectral lines emitted at different temperatures, possibly with differences among lines from higher Fe ionization stages. The CME was also observed by the SOHO/UVCS instrument: the spectrograph slit was centered at 1.7 R⊙, at a latitude of 5° SW and recorded a sudden increase in the O VI λλ1032–1037 and Si XII λ520 spectral line intensities, representative of the CME front transit.

  2. Magnetic field re-arrangement after prominence eruption

    International Nuclear Information System (INIS)

    Kopp, R.A.; Poletto, G.

    1986-01-01

    It has long been known that magnetic reconnection plays a fundamental role in a variety of solar events. Although mainly invoked in flare problems, large-scale loops interconnecting active regions, evolving coronal hole boundaries, the solar magnetic cycle itself, provide different evidence of phenomena which involve magnetic reconnection. A further example might be given by the magnetic field rearrangement which occurs after the eruption of a prominence. Since most often a prominence reforms after its disappearance and may be observed at about the same position it occupied before erupting, the magnetic field has to undergo a temporary disruption to relax back, via reconnection, to a configuration similar to the previous one. The above sequence of events is best observable in the case of two-ribbon (2-R) flares but most probably is associated with all filament eruptions. Even if the explanation of the magnetic field rearrangement after 2-R flares in terms of reconnection is generally accepted, the lack of a three-dimensional model capable of describing the field reconfiguration, has prevented, up to now, a thorough analysis of its topology as traced by Hα/x-ray loops. The purpose of the present work is to present a numerical technique which enables one to predict and visualize the reconnected configuration, at any time t, and therefore allows one to make a significant comparison of observations and model predictions throughout the whole process. 5 refs., 3 figs

  3. MAGNETIC FIELD IN ATYPICAL PROMINENCE STRUCTURES: BUBBLE, TORNADO, AND ERUPTION

    Energy Technology Data Exchange (ETDEWEB)

    Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France); López Ariste, A. [IRAP—CNRS UMR 5277, 14, Av. E. Belin, F-31400 Toulouse (France); Dalmasse, K. [CISL/HAO, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States); Gelly, B., E-mail: p.levens.1@research.gla.ac.uk, E-mail: brigitte.schmieder@obspm.fr [CNRS UMR 3718 THEMIS, La Laguna, Tenerife (Spain)

    2016-08-01

    Spectropolarimetric observations of prominences have been obtained with the THEMIS telescope during four years of coordinated campaigns. Our aim is now to understand the conditions of the cool plasma and magnetism in “atypical” prominences, namely when the measured inclination of the magnetic field departs, to some extent, from the predominantly horizontal field found in “typical” prominences. What is the role of the magnetic field in these prominence types? Are plasma dynamics more important in these cases than the magnetic support? We focus our study on three types of “atypical” prominences (tornadoes, bubbles, and jet-like prominence eruptions) that have all been observed by THEMIS in the He i D{sub 3} line, from which the Stokes parameters can be derived. The magnetic field strength, inclination, and azimuth in each pixel are obtained by using the inversion method of principal component analysis on a model of single scattering in the presence of the Hanle effect. The magnetic field in tornadoes is found to be more or less horizontal, whereas for the eruptive prominence it is mostly vertical. We estimate a tendency toward higher values of magnetic field strength inside the bubbles than outside in the surrounding prominence. In all of the models in our database, only one magnetic field orientation is considered for each pixel. While sufficient for most of the main prominence body, this assumption appears to be oversimplified in atypical prominence structures. We should consider these observations as the result of superposition of multiple magnetic fields, possibly even with a turbulent field component.

  4. Heating of an Erupting Prominence Associated with a Solar Coronal Mass Ejection on 2012 January 27

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin-Yi; Moon, Yong-Jae; Kim, Kap-Sung [Department of Astronomy and Space Science, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104 (Korea, Republic of); Raymond, John C.; Reeves, Katharine K. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2017-07-20

    We investigate the heating of an erupting prominence and loops associated with a coronal mass ejection and X-class flare. The prominence is seen as absorption in EUV at the beginning of its eruption. Later, the prominence changes to emission, which indicates heating of the erupting plasma. We find the densities of the erupting prominence using the absorption properties of hydrogen and helium in different passbands. We estimate the temperatures and densities of the erupting prominence and loops seen as emission features using the differential emission measure method, which uses both EUV and X-ray observations from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory and the X-ray Telescope on board Hinode . We consider synthetic spectra using both photospheric and coronal abundances in these calculations. We verify the methods for the estimation of temperatures and densities for the erupting plasmas. Then, we estimate the thermal, kinetic, radiative loss, thermal conduction, and heating energies of the erupting prominence and loops. We find that the heating of the erupting prominence and loop occurs strongly at early times in the eruption. This event shows a writhing motion of the erupting prominence, which may indicate a hot flux rope heated by thermal energy release during magnetic reconnection.

  5. Study of a Large Helical Eruptive Prominence Associated with ...

    Indian Academy of Sciences (India)

    2001-04-21

    Apr 21, 2001 ... morphology of the event, energy budget of the prominence and associated. CMEs. ... magnetically driven and internally powered. Key words. ... Solar prominences are ribbons of cool (∼8000 K) dense gas (∼10. −11 gcm. −3. ) ...

  6. Eruptive prominences and long-delay geomagnetic storms

    International Nuclear Information System (INIS)

    Wright, C.S.

    1983-01-01

    The relationship between disappearing solar fragments and geomagnetic disturbances was investigated. It is shown that long-delay storms are associated with filaments well removed from the disc centre, and particularly in the case of large filaments and prominences, the proportion of events that produce long-delay storms increases with angular distance from the centre

  7. Quiescent and Eruptive Prominences at Solar Minimum: A Statistical Study via an Automated Tracking System

    Science.gov (United States)

    Loboda, I. P.; Bogachev, S. A.

    2015-07-01

    We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304Å line taken close to the solar minimum of 2008-2009 and mainly focus on quiescent and quiescent-eruptive prominences. We detect a total of 389 individual features ranging from 25×25 to 150×500 Mm2 in size and obtain distributions of many of their spatial characteristics, such as latitudinal position, height, size, and shape. To study their dynamics, we classify prominences as either stable or eruptive and calculate their average centroid velocities, which are found to rarely exceed 3 km/s. In addition, we give rough estimates of mass and gravitational energy for every detected prominence and use these values to estimate the total mass and gravitational energy of all simultaneously existing prominences (1012 - 1014 kg and 1029 - 1031 erg). Finally, we investigate the form of the gravitational energy spectrum of prominences and derive it to be a power-law of index -1.1 ± 0.2.

  8. The Apparent Critical Decay Index at the Onset of Solar Prominence Eruptions

    Science.gov (United States)

    Zuccarello, F. P.; Aulanier, G.; Gilchrist, S. A.

    2016-04-01

    A magnetic flux rope (MFR) embedded in a line-tied external magnetic field that decreases with height as {z}-n is unstable to perturbations if the decay index of the field n is larger than a critical value. The onset of this instability, called torus instability, is one of the main mechanisms that can initiate coronal mass ejections. Since flux ropes often possess magnetic dips that can support prominence plasma, this is also a valuable mechanism to trigger prominence eruptions. Magnetohydrodynamic (MHD) simulations of the formation and/or emergence of MFRs suggest a critical value for the onset of the instability in the range [1.4-2]. However, detailed observations of prominences suggest a value in the range [0.9-1.1]. In this Letter, by using a set of MHD simulations, we show why the large discrepancy between models and observations is only apparent. Our simulations indeed show that the critical decay index at the onset of the eruption is n=1.4+/- 0.1 when computed at the apex of the flux rope axis, while it is n=1.1+/- 0.1 when it is computed at the altitude of the topmost part of the distribution of magnetic dips. The discrepancy only arises because weakly twisted curved flux ropes do not have dips up to the altitude of their axis.

  9. ENERGY RELEASE FROM IMPACTING PROMINENCE MATERIAL FOLLOWING THE 2011 JUNE 7 ERUPTION

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert, H. R.; Inglis, A. R.; Mays, M. L.; Ofman, L.; Thompson, B. J.; Young, C. A. [Solar Physics Laboratory, Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-10-10

    Solar filaments exhibit a range of eruptive-like dynamic activity, ranging from the full or partial eruption of the filament mass and surrounding magnetic structure as a coronal mass ejection to a fully confined or failed eruption. On 2011 June 7, a dramatic partial eruption of a filament was observed by multiple instruments on board the Solar Dynamics Observatory (SDO) and Solar-Terrestrial Relations Observatory. One of the interesting aspects of this event is the response of the solar atmosphere as non-escaping material falls inward under the influence of gravity. The impact sites show clear evidence of brightening in the observed extreme ultraviolet wavelengths due to energy release. Two plausible physical mechanisms for explaining the brightening are considered: heating of the plasma due to the kinetic energy of impacting material compressing the plasma, or reconnection between the magnetic field of low-lying loops and the field carried by the impacting material. By analyzing the emission of the brightenings in several SDO/Atmospheric Imaging Assembly wavelengths, and comparing the kinetic energy of the impacting material (7.6 × 10{sup 26}-5.8 × 10{sup 27} erg) to the radiative energy (≈1.9 × 10{sup 25}-2.5 × 10{sup 26} erg), we find the dominant mechanism of energy release involved in the observed brightening is plasma compression.

  10. Energy Release from Impacting Prominence Material Following the 2011 June 7 Eruption

    Science.gov (United States)

    Gilbert, H. R.; Inglis, A. R.; Mays, M. L.; Ofman, L.; Thompson, B. J.; Young, C. A.

    2013-01-01

    Solar filaments exhibit a range of eruptive-like dynamic activity, ranging from the full or partial eruption of the filament mass and surrounding magnetic structure as a coronal mass ejection to a fully confined or failed eruption. On 2011 June 7, a dramatic partial eruption of a filament was observed by multiple instruments on board the Solar Dynamics Observatory (SDO) and Solar-Terrestrial Relations Observatory. One of the interesting aspects of this event is the response of the solar atmosphere as non-escaping material falls inward under the influence of gravity. The impact sites show clear evidence of brightening in the observed extreme ultraviolet wavelengths due to energy release. Two plausible physical mechanisms for explaining the brightening are considered: heating of the plasma due to the kinetic energy of impacting material compressing the plasma, or reconnection between the magnetic field of low-lying loops and the field carried by the impacting material. By analyzing the emission of the brightenings in several SDO/Atmospheric Imaging Assembly wavelengths, and comparing the kinetic energy of the impacting material (7.6 × 10(exp 26) - 5.8 × 10(exp 27) erg) to the radiative energy (approx. 1.9 × 10(exp 25) - 2.5 × 10(exp 26) erg), we find the dominant mechanism of energy release involved in the observed brightening is plasma compression.

  11. A model of 'disparitions brusques' (sudden disappearance of eruptive prominences) as an instability driven by MHD waves

    International Nuclear Information System (INIS)

    Sakai, J.; Nishikawa, K.-I.

    1982-04-01

    A mode of 'disparitions brusques' (sudden disappearance of eruptive prominences) is discussed based on the Kippenhahn and Schluter configuration. It is shown that Kippenhahn and Schluter's current sheet is very weakly unstable against magnetic reconnecting modes during the lifetime of quiescent prominences. Disturbances in the form of fast magnetosonic waves originating from nearby active regions or the changes of whole magnetic configuration due to newly emerged magnetic flux may trigger a rapid growing instability associated with magnetic field reconnection. This instability gives rise to disruptions of quiescent prominences and also generates high energy particles. (author)

  12. Development and Parameters of a Non-Self-Similar CME Caused by the Eruption of a Quiescent Prominence

    Science.gov (United States)

    Kuzmenko, I. V.; Grechnev, V. V.

    2017-10-01

    The eruption of a large quiescent prominence on 17 August 2013 and an associated coronal mass ejection (CME) were observed from different vantage points by the Solar Dynamics Observatory (SDO), the Solar-Terrestrial Relations Observatory (STEREO), and the Solar and Heliospheric Observatory (SOHO). Screening of the quiet Sun by the prominence produced an isolated negative microwave burst. We estimated the parameters of the erupting prominence from a radio absorption model and measured them from 304 Å images. The variations of the parameters as obtained by these two methods are similar and agree within a factor of two. The CME development was studied from the kinematics of the front and different components of the core and their structural changes. The results were verified using movies in which the CME expansion was compensated for according to the measured kinematics. We found that the CME mass (3.6 × 10^{15} g) was mainly supplied by the prominence (≈ 6 × 10^{15} g), while a considerable part drained back. The mass of the coronal-temperature component did not exceed 10^{15} g. The CME was initiated by the erupting prominence, which constituted its core and remained active. The structural and kinematical changes started in the core and propagated outward. The CME structures continued to form during expansion, which did not become self-similar up to 25 R_{⊙}. The aerodynamic drag was insignificant. The core formed during the CME rise to 4 R_{⊙} and possibly beyond. Some of its components were observed to straighten and stretch outward, indicating the transformation of tangled structures of the core into a simpler flux rope, which grew and filled the cavity as the CME expanded.

  13. PRE-FLARE CORONAL JET AND EVOLUTIONARY PHASES OF A SOLAR ERUPTIVE PROMINENCE ASSOCIATED WITH THE M1.8 FLARE: SDO AND RHESSI OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Bhuwan; Kushwaha, Upendra [Udaipur Solar Observatory, Physical Research Laboratory, Udaipur 313001 (India); Veronig, Astrid M. [Kanzelhöhe Observatory/Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Cho, K.-S., E-mail: bhuwan@prl.res.in [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2016-12-01

    We investigate the triggering, activation, and ejection of a solar eruptive prominence that occurred in a multi-polar flux system of active region NOAA 11548 on 2012 August 18 by analyzing data from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory , the Reuven Ramaty High Energy Solar Spectroscopic Imager , and the Extreme Ultraviolet Imager/Sun Earth Connection Coronal and Heliospheric Investigation on board the Solar Terrestrial Relation Observatory . Prior to the prominence activation, we observed striking coronal activities in the form of a blowout jet, which is associated with the rapid eruption of a cool flux rope. Furthermore, the jet-associated flux rope eruption underwent splitting and rotation during its outward expansion. These coronal activities are followed by the prominence activation during which it slowly rises with a speed of ∼12 km s{sup −1} while the region below the prominence emits gradually varying EUV and thermal X-ray emissions. From these observations, we propose that the prominence eruption is a complex, multi-step phenomenon in which a combination of internal (tether-cutting reconnection) and external (i.e., pre-eruption coronal activities) processes are involved. The prominence underwent catastrophic loss of equilibrium with the onset of the impulsive phase of an M1.8 flare, suggesting large-scale energy release by coronal magnetic reconnection. We obtained signatures of particle acceleration in the form of power-law spectra with hard electron spectral index ( δ  ∼ 3) and strong HXR footpoint sources. During the impulsive phase, a hot EUV plasmoid was observed below the apex of the erupting prominence that ejected in the direction of the prominence with a speed of ∼177 km s{sup −1}. The temporal, spatial, and kinematic correlations between the erupting prominence and the plasmoid imply that the magnetic reconnection supported the fast ejection of prominence in the lower corona.

  14. Evidence for Mixed Helicity in Erupting Filaments

    Science.gov (United States)

    Muglach, K.; Wang, Y.-M.; Kliem, B.

    2009-09-01

    Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament "barbs" is opposite in sign to and dominates that of the overlying arcade.

  15. DESTABILIZATION OF A SOLAR PROMINENCE/FILAMENT FIELD SYSTEM BY A SERIES OF EIGHT HOMOLOGOUS ERUPTIVE FLARES LEADING TO A CME

    Energy Technology Data Exchange (ETDEWEB)

    Panesar, Navdeep K.; Moore, Ronald L. [Center for Space Plasma and Aeronomic Research (CSPAR), UAH, Huntsville, AL 35805 (United States); Sterling, Alphonse C. [Heliophysics and Planetary Science Office, ZP13, Marshall Space Flight Center, Huntsville, AL 35812 (United States); Innes, Davina E., E-mail: navdeep.k.panesar@nasa.gov [Max Planck Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany)

    2015-09-20

    Homologous flares are flares that occur repetitively in the same active region, with similar structure and morphology. A series of at least eight homologous flares occurred in active region NOAA 11237 over 2011 June 16–17. A nearby prominence/filament was rooted in the active region, and situated near the bottom of a coronal cavity. The active region was on the southeast solar limb as seen from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, and on the disk as viewed from the Solar TErrestrial RElations Observatory/EUVI-B. The dual perspective allows us to study in detail behavior of the prominence/filament material entrained in the magnetic field of the repeatedly erupting system. Each of the eruptions were mainly confined, but expelled hot material into the prominence/filament cavity system (PFCS). The field carrying and containing the ejected hot material interacted with the PFCS and caused it to inflate, resulting in a step-wise rise of the PFCS approximately in step with the homologous eruptions. The eighth eruption triggered the PFCS to move outward slowly, accompanied by a weak coronal dimming. As this slow PFCS eruption was underway, a final “ejective” flare occurred in the core of the active region, resulting in strong dimming in the EUVI-B images and expulsion of a coronal mass ejection (CME). A plausible scenario is that the repeated homologous flares could have gradually destabilized the PFCS, and its subsequent eruption removed field above the acitive region and in turn led to the ejective flare, strong dimming, and CME.

  16. Solar prominences

    CERN Document Server

    Engvold, Oddbjørn

    2015-01-01

    This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of promine...

  17. Fuego Volcano eruption (Guatemala, 1974): evidence of a tertiary fragmentation?

    International Nuclear Information System (INIS)

    Brenes-Andre, Jose

    2014-01-01

    Values for mode and dispersion calculated from SFT were analyzed using the SFT (Sequential Fragmentation/Transport) model to Fuego Volcano eruption (Guatemala, 1974). Analysis results have showed that the ideas initially proposed for Irazu, can be applied to Fuego Volcano. Experimental evidence was found corroborating the existence of tertiary fragmentations. (author) [es

  18. Direct evidence of an eruptive, filament-hosting magnetic flux rope leading to a fast solar coronal mass ejection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Bin; Gary, D. E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Bastian, T. S., E-mail: bin.chen@cfa.harvard.edu [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States)

    2014-10-20

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  19. Direct Evidence of an Eruptive, Filament-hosting Magnetic Flux Rope Leading to a Fast Solar Coronal Mass Ejection

    Science.gov (United States)

    Chen, Bin; Bastian, T. S.; Gary, D. E.

    2014-10-01

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  20. Direct evidence of an eruptive, filament-hosting magnetic flux rope leading to a fast solar coronal mass ejection

    International Nuclear Information System (INIS)

    Chen, Bin; Gary, D. E.; Bastian, T. S.

    2014-01-01

    Magnetic flux ropes (MFRs) are believed to be at the heart of solar coronal mass ejections (CMEs). A well-known example is the prominence cavity in the low corona that sometimes makes up a three-part white-light (WL) CME upon its eruption. Such a system, which is usually observed in quiet-Sun regions, has long been suggested to be the manifestation of an MFR with relatively cool filament material collecting near its bottom. However, observational evidence of eruptive, filament-hosting MFR systems has been elusive for those originating in active regions. By utilizing multi-passband extreme-ultraviolet (EUV) observations from Solar Dynamics Observatory/Atmospheric Imaging Assembly, we present direct evidence of an eruptive MFR in the low corona that exhibits a hot envelope and a cooler core; the latter is likely the upper part of a filament that undergoes a partial eruption, which is later observed in the upper corona as the coiled kernel of a fast, WL CME. This MFR-like structure exists more than 1 hr prior to its eruption, and displays successive stages of dynamical evolution, in which both ideal and non-ideal physical processes may be involved. The timing of the MFR kinematics is found to be well correlated with the energy release of the associated long-duration C1.9 flare. We suggest that the long-duration flare is the result of prolonged energy release associated with the vertical current sheet induced by the erupting MFR.

  1. EVIDENCE FOR ROTATIONAL MOTIONS IN THE FEET OF A QUIESCENT SOLAR PROMINENCE

    International Nuclear Information System (INIS)

    Orozco Suárez, D.; Asensio Ramos, A.; Trujillo Bueno, J.

    2012-01-01

    We present observational evidence of apparent plasma rotational motions in the feet of a solar prominence. Our study is based on spectroscopic observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time sequence of spectra with 34 s cadence placing the slit of the spectrograph almost parallel to the solar limb and crossing two feet of an intermediate size, quiescent hedgerow prominence. The data show opposite Doppler shifts, ±6 km s –1 , at the edges of the prominence feet. We argue that these shifts may be interpreted as prominence plasma rotating counterclockwise around the vertical axis to the solar surface as viewed from above. The evolution of the prominence seen in EUV images taken with the Solar Dynamics Observatory provided us with clues to interpret the results as swirling motions. Moreover, time-distance images taken far from the central wavelength show plasma structures moving parallel to the solar limb with velocities of about 10-15 km s –1 . Finally, the shapes of the observed intensity profiles suggest the presence of, at least, two components at some locations at the edges of the prominence feet. One of them is typically Doppler shifted (up to ∼20 km s –1 ) with respect to the other, thus suggesting the existence of supersonic counter-streaming flows along the line of sight.

  2. Signs of helicity in solar prominences and related features

    Science.gov (United States)

    Martin, S.

    This review illustrates several ways to identify the chirality (handedness) of solar prominences (filaments) from their structure and the structure of their surrounding magnetic fields in the chromosphere and corona. For prominences, these structural elements include the axial magnetic field direction, orientation of barbs, and direction of the prominence fine structure. The surrounding structures include the pattern of fibrils beneath the prominences and the pattern of coronal loops above the prominences. These ways of identifying chirality are then interpreted in terms of the formal definitions of helicity to yield a consistent set of one-to-one helicity relationships for all features. The helicity of some prominences can also be independently determined during their eruption by their fine structure, apparent crossings in the line-of-sight of different parts of the same prominence, and by large- scale twist of the prominence structure. Unlike observations of prominences (filaments) observed prior to eruption, in some cases evidence of both signs of helicity are found within the same erupting prominence. This indicates the continued application of forces on the prominences during the eruption process or the possible introduction of force(s) not present during earlier stages of their evolution.

  3. Unambiguous Evidence of Filament Splitting-induced Partial Eruptions

    Science.gov (United States)

    Cheng, X.; Kliem, B.; Ding, M. D.

    2018-03-01

    Coronal mass ejections are often considered to result from the full eruption of a magnetic flux rope (MFR). However, it is recognized that, in some events, the MFR may release only part of its flux, with the details of the implied splitting not completely established due to limitations in observations. Here, we investigate two partial eruption events including a confined and a successful one. Both partial eruptions are a consequence of the vertical splitting of a filament-hosting MFR involving internal reconnection. A loss of equilibrium in the rising part of the magnetic flux is suggested by the impulsive onset of both events and by the delayed onset of reconnection in the confined event. The remaining part of the flux might be line-tied to the photosphere in a bald patch (BP) separatrix surface, and we confirm the existence of extended BP sections for the successful eruption. The internal reconnection is signified by brightenings in the body of one filament and between the rising and remaining parts of both filaments. It evolves quickly into the standard current sheet reconnection in the wake of the eruption. As a result, regardless of being confined or successful, both eruptions produce hard X-ray sources and flare loops below the erupting but above the surviving flux, as well as a pair of flare ribbons enclosing the latter.

  4. A critical evaluation of the evidence for multiple Late Pleistocene eruptions of Laacher See Volcano

    DEFF Research Database (Denmark)

    Zernack, Anke Verena; Hoggard, Christian Steven; Sauer, Florian Rudolf

    The c. 12,900 BP Plinian eruption of Laacher See Volcano is one of the largest known volcanic events of the Late Pleistocene in the Northern Hemisphere. It buried proximal areas under tens of meters of pyroclastic flow, surge and fallout deposits and deposited a widespread tephra layer across much...... of dispersal of the products from varying eruptive stages and some sites even report two distinct Laacher See Tephra layers that have been interpreted as evidence of a precursor eruption. In order to assess the potential for multiple Late Pleistocene eruptions of Laacher See Volcano, we have compiled...

  5. Unambiguous Evidence of Coronal Implosions during Solar Eruptions and Flares

    Science.gov (United States)

    Wang, Juntao; Simões, P. J. A.; Fletcher, L.

    2018-05-01

    In the implosion conjecture, coronal loops contract as the result of magnetic energy release in solar eruptions and flares. However, after almost two decades, observations of this phenomenon are still rare and most previous reports are plagued by projection effects so that loop contraction could be either true implosion or just a change in loop inclination. In this paper, to demonstrate the reality of loop contractions in the global coronal dynamics, we present four events with the continuously contracting loops in an almost edge-on geometry from the perspective of SDO/AIA, which are free from the ambiguity caused by the projection effects, also supplemented by contemporary observations from STEREO for examination. In the wider context of observations, simulations and theories, we argue that the implosion conjecture is valid in interpreting these events. Furthermore, distinct properties of the events allow us to identify two physical categories of implosion. One type demonstrates a rapid contraction at the beginning of the flare impulsive phase, as magnetic free energy is removed rapidly by a filament eruption. The other type, which has no visible eruption, shows a continuous loop shrinkage during the entire flare impulsive phase, which we suggest shows the ongoing conversion of magnetic free energy in a coronal volume. Corresponding scenarios are described that can provide reasonable explanations for the observations. We also point out that implosions may be suppressed in cases when a heavily mass-loaded filament is involved, possibly serving as an alternative account for their observational rarity.

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

    Science.gov (United States)

    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.

  7. Re-interpreting Prominences Classified as Tornadoes

    Science.gov (United States)

    Martin, Sara F.; Venkataramanasastry, Aparna

    2015-04-01

    Some papers in the recent literature identify tornado prominences with barbs of quiescent prominences while papers in the much older historic literature include a second category of tornado prominence that does not correspond to a barb of a quiescent prominence. The latter are described as prominence mass rotating around a nearly vertical axis prior to its eruption and the rotation was verified by spectral measurements. From H alpha Doppler-shifted mass motions recorded at Helio Research or the Dutch Open Telescope, we illustrate how the apparent tornado-like motions, identified with barbs, are illusions in our mind’s eye resulting from poorly resolved counterstreaming threads of mass in the barbs of quiescent prominences. In contrast, we confirm the second category of rotational motion in prominences shortly before and during eruption. In addition, we identify this second category as part of the late phase of a phenomenon called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of the prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption continues, the longer lasting leg becomes nearly vertical and its rotational motion also continues. If only this phase of the eruption was observed, as in some historic cases, it was called a tornado prominence. However, when we now observe entire eruptions in time-lapse sequences, the similarity to terrestrial tornadoes is lost. We conclude that neither prominence barbs, that give the illusion of rotation, nor the cases of true rotational motion, in the legs of erupting prominences, are usefully described as tornado prominences when the complete prominence structure or complete erupting event is observed.

  8. Late Holocene history of Chaitén Volcano: new evidence for a 17th century eruption

    Science.gov (United States)

    Lara, Luis E.; Moreno, Rodrigo; Amigo, Álvaro; Hoblitt, Richard P.; Pierson, Thomas C.

    2013-01-01

    Prior to May 2008, it was thought that the last eruption of Chaitén Volcano occurred more than 5,000 years ago, a rather long quiescent period for a volcano in such an active arc segment. However, increasingly more Holocene eruptions are being identified. This article presents both geological and historical evidence for late Holocene eruptive activity in the 17th century (AD 1625-1658), which included an explosive rhyolitic eruption that produced pumice ash fallout east of the volcano and caused channel aggradation in the Chaitén River. The extents of tephra fall and channel aggradation were similar to those of May 2008. Fine ash, pumice and obsidian fragments in the pre-2008 deposits are unequivocally derived from Chaitén Volcano. This finding has important implications for hazards assessment in the area and suggests the eruptive frequency and magnitude should be more thoroughly studied.

  9. Chemical Evidence for Vertical Transport from Magma Chambers to the Surface During Mid-Ocean Ridge Volcanic Eruptions

    Science.gov (United States)

    Sinton, J. M.; Rubin, K. H.

    2009-12-01

    Many mid-ocean ridge eruptions show significant internal chemical heterogeneity; in general, the amount of chemical heterogeneity within eruptions scales with erupted volume. These variations reflect magmatic processes occurring in magma reservoirs prior to or possibly during eruption. For example, systematic variations in Mg# with along-axis distance in the early 90’s Aldo-Kihi (S. EPR near 17.5°S), 1996 N. Gorda, 1993 Co-Axial (Juan de Fuca Ridge), and 1991-2 and 2005-6 9°50’N EPR eruptions is unlikely to be related to fractionation during emplacement, and rather reflects variations in sub-axial magma reservoirs prior to eruption. Such variations are inconsistent with well-mixed sub-axial reservoirs and, in some cases, require relatively long-lived, systematic variations in reservoir temperatures along axis. Chemical heterogeneity within the Aldo-Kihi eruption preserves spatial variations in mantle-derived isotopic and trace element ratios with implications for the temporal and spatial scales of magma injections to the crust and along-axis mixing within shallow reservoirs. These spatial variations are difficult to reconcile with significant (> ~1 km) along-axis magma transport, as are striking correlations of chemical compositions with surface geological discontinuities or seismically imaged sub-axial magma chamber reflectors in the S. Hump (S. EPR), 9°50’N EPR, N. Gorda and 1975-1984 Krafla (N. Iceland) eruptive units. Rather, spatial correlations between surface lava compositions and sub-axial magma chamber properties or long-lived axial morphology suggest that most of the erupted magma was transported nearly vertically from the underlying reservoirs to the surface during these eruptions. In the case of the Krafla eruption, coincident deformation suggests a component of lateral melt migration at depth, despite chemical evidence for vertical transport of erupted lava from more than one chemical reservoir. In addition, along-ridge movement of earthquake

  10. Miniature Filament Eruptions and their Reconnections in X-Ray Jets: Evidence for a New Paradigm

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David A.

    2014-01-01

    We investigate the onset of approximately10 random X-ray jets observed by Hinode/XRT. Each jet was near the limb in a polar coronal hole, and showed a ``bright point'' in an edge of the base of the jet, as is typical for previously-observed X-ray jets. We examined SDO/AIA EUV images of each of the jets over multiple AIA channels, including 304 Ang, which detects chromospheric emissions, and 171, 193, and 211 Ang, which detect cooler-coronal emissions. We find the jets to result from eruptions of miniature (size less than approximately 10 arcsec) filaments from the bases of the jets. Much of the erupting-filament material forms a chromospheric-temperature jet. In the cool-coronal channels, often the filament appears in absorption and the jet in emission. The jet bright point forms at the location from which the miniature filament is ejected, analogous to the formation of a standard solar flare in the wake of the eruption of a typical larger-scale chromospheric filament. Thus these X-ray jets and their bright points are made by miniature filament eruptions. They are evidently produced the same way as an on-disk coronal jet we observed in Adams et al. (2014); that on-disk jet had no obvious emerging magnetic field in its base. We conclude that, for many jets, the standard idea of X-ray jets forming from reconnection between emerging flux and preexisting coronal field is incorrect. ACS and RLM were supported by funding from NASA/LWS, Hinode, and ISSI.

  11. Lava channel formation during the 2001 eruption on Mount Etna: evidence for mechanical erosion.

    Science.gov (United States)

    Ferlito, Carmelo; Siewert, Jens

    2006-01-20

    We report the direct observation of a peculiar lava channel that was formed near the base of a parasitic cone during the 2001 eruption on Mount Etna. Erosive processes by flowing lava are commonly attributed to thermal erosion. However, field evidence strongly suggests that models of thermal erosion cannot explain the formation of this channel. Here, we put forward the idea that the essential erosion mechanism was abrasive wear. By applying a simple model from tribology we demonstrate that the available data agree favorably with our hypothesis. Consequently, we propose that erosional processes resembling the wear phenomena in glacial erosion are possible in a volcanic environment.

  12. Geological Evidences for a Large Tsunami Generated by the 7.3 ka Kikai Caldera Eruption, Southern Japan

    Science.gov (United States)

    Yamada, M.; Fujino, S.; Satake, K.

    2017-12-01

    The 7.3 ka eruption of Kikai volcano, southern Kyushu, Japan, is one of the largest caldera-forming eruption in the world. Given that a huge caldera was formed in shallow sea area during the eruption, a tsunami must have been generated by a sea-level change associated. Pyroclastic flow and tsunami deposits by the eruption have been studied around the caldera, but they are not enough to evaluate the tsunami size. The goal of this study is to unravel sizes of tsunami and triggering caldera collapse by numerical simulations based on a widely-distributed tsunami deposit associated with the eruption. In this presentation, we will provide an initial data on distribution of the 7.3 ka tsunami deposit contained in sediment cores taken at three coastal lowlands in Wakayama, Tokushima, and Oita prefectures (560 km, 520 km, and 310 km north-east from the caldera, respectively). A volcanic ash from the eruption (Kikai Akahoya tephra: K-Ah) is evident in organic-rich muddy sedimentary sequence in all sediment cores. Up to 6-cm-thick sand layer, characterized by a grading structure and sharp bed boundary with lower mud, is observed immediately beneath the K-Ah tephra in all study sites. These sedimentary characteristics and broad distribution indicate that the sand layer was most likely deposited by a tsunami which can propagate to a wide area, but not by a local storm surge. Furthermore, the stratigraphic relationship implies that the study sites must have been inundated by the tsunami prior to the ash fall. A sand layer is also evident within the K-Ah tephra layer, suggesting that the sand layer was probably formed by a subsequent tsunami wave during the ash fall. These geological evidences for the 7.3 ka tsunami inundation will contribute to a better understanding of the caldera collapse and the resultant tsunami, but also of the tsunami generating system in the eruptive process.

  13. Evidence for water influx from a caldera lake during the explosive hydromagmatic eruption of 1790, Kilauea volcano, Hawaii

    Science.gov (United States)

    Mastin, L.G.

    1997-01-01

    In 1790 a major hydromagmatic eruption at the summit of Kilauea volcano, Hawaii, deposited up to 10 m of pyroclastic fall and surge deposits and killed several dozen Hawaiian natives who were crossing the island. Previous studies have hypothesized that the explosivity of this eruption was due to the influx of groundwater into the conduit and mixing of the groundwater with ascending magma. This study proposes that surface water, not groundwater, was the agent responsible for the explosiveness of the eruption. That is, a lake or pond may have existed in the caldera in 1790 and explosions may have taken place when magma ascended into the lake from below. That assertion is based on two lines of evidence: (1) high vesicularity (averaging 73% of more than 3000 lapilli) and high vesicle number density (105-107 cm-3 melt) of pumice clasts suggest that some phases of the eruption involved vigorous, sustained magma ascent; and (2) numerical calculations suggest that under most circumstances, hydrostatic pressure would not be sufficient to drive water into the eruptive conduit during vigorous magma ascent unless the water table were above the ground surface. These results are supported by historical data on the rate of infilling of the caldera floor during the early 1800s. When extrapolated back to 1790, they suggest that the caldera floor was below the water table.

  14. EIT Crinkles as Evidence for the Breakout Model of Solar Eruptions

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, Ronald L.

    2001-01-01

    , with complexities that preclude a simple determination of the dynamics in the core at the times of eruption. From the BCS spectra, we find that the core region expends energy at a rate of approximately 10(exp 26) ergs/s during the time of the growth of the EIT crinkles; this rate is an upper limit to energy expended in the reconnections opening the overlying fields. Energy losses occur at an order of magnitude higher rate near the time of the peak of the events. There is little evidence of asymmetry in the spectra, consistent with the majority of the mass flows occurring normal to the line of sight. Both events have similar electron temperature dependencies on time.

  15. Compositional Trends in Acid Fluids of Copahue Volcano, Argentina: Evidence for a failed eruption in 2004?

    Science.gov (United States)

    Kading, T. J.; Brophy, M.; Varekamp, J. C.

    2008-12-01

    The concentrations and fluxes of major, minor, and trace elements in the crater lake, volcanic spring, and acidified watershed of Copahue Volcano, Neuquen province, Argentina, have been monitored over the last decade. The 2000 Copahue eruption resulted in enhanced S/Cl, increased concentrations and fluxes of rock forming elements (especially Mg and Na) with strongly raised Mg/Cl and Mg/K values. The degree of LREE enrichment decreased and a pronounced Eu anomaly developed in the fluids (Eu/Eu*> rock values). These patterns are explained as the result of hot acid fluid attack on newly intruded magma, with early dissolution of olivine (Mg spike) and plagioclase (Na spike, Eu anomaly). Similar compositional changes were observed in water samples taken in November, 2004, but no eruption occurred. These may be the signals of a small magmatic intrusion into the hydrothermal system, which failed to continue into an eruption. The compositional changes of Copahue volcanic fluids over the last decade will be discussed in the context of chemical signals of an actual and a suspected 'failed eruption'.

  16. Expanding and Contracting Coronal Loops as Evidence of Vortex Flows Induced by Solar Eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Dudík, J. [Astronomical Institute of the Czech Academy of Sciences, Fričova 298, 251 65 Ondřejov (Czech Republic); Zuccarello, F. P.; Aulanier, G.; Schmieder, B.; Démoulin, P., E-mail: jaroslav.dudik@asu.cas.cz [LESIA, Observatoire de Paris, Psl Research University, CNRS, Sorbonne Universits, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

    2017-07-20

    Eruptive solar flares were predicted to generate large-scale vortex flows at both sides of the erupting magnetic flux rope. This process is analogous to a well-known hydrodynamic process creating vortex rings. The vortices lead to advection of closed coronal loops located at the peripheries of the flaring active region. Outward flows are expected in the upper part and returning flows in the lower part of the vortex. Here, we examine two eruptive solar flares, the X1.1-class flare SOL2012-03-05T03:20 and the C3.5-class SOL2013-06-19T07:29. In both flares, we find that the coronal loops observed by the Atmospheric Imaging Assembly in its 171 Å, 193 Å, or 211 Å passbands show coexistence of expanding and contracting motions, in accordance with the model prediction. In the X-class flare, multiple expanding and contracting loops coexist for more than 35 minutes, while in the C-class flare, an expanding loop in 193 Å appears to be close by and cotemporal with an apparently imploding loop arcade seen in 171 Å. Later, the 193 Å loop also switches to contraction. These observations are naturally explained by vortex flows present in a model of eruptive solar flares.

  17. Giant caldera in the Arctic Ocean: Evidence of the catastrophic eruptive event.

    Science.gov (United States)

    Piskarev, Alexey; Elkina, Daria

    2017-04-10

    A giant caldera located in the eastern segment of the Gakkel Ridge could be firstly seen on the bathymetric map of the Arctic Ocean published in 1999. In 2014, seismic and multibeam echosounding data were acquired at the location. The caldera is 80 km long, 40 km wide and 1.2 km deep. The total volume of ejected volcanic material is estimated as no less than 3000 km 3 placing it into the same category with the largest Quaternary calderas (Yellowstone and Toba). Time of the eruption is estimated as ~1.1 Ma. Thin layers of the volcanic material related to the eruption had been identified in sedimentary cores located about 1000 km away from the Gakkel Ridge. The Gakkel Ridge Caldera is the single example of a supervolcano in the rift zone of the Mid-Oceanic Ridge System.

  18. Seismo-acoustic evidence for an avalanche driven phreatic eruption through a beheaded hydrothermal system: An example from the 2012 Tongariro eruption

    Science.gov (United States)

    Jolly, A.D.; Jousset, P.; Lyons, J.J.; Carniel, R.; Fournier, R.; Fry, B.; Miller, C.

    2016-01-01

    The 6 August 2012 Te Maari eruption comprises a complex eruption sequence including multiple eruption pulses, a debris avalanche that propagated ~ 2 km from the vent, and the formation of a 500 m long, arcuate chasm, located ~ 300 m from the main eruption vent. The eruption included 6 distinct impulses that were coherent across a local infrasound network marking the eruption onset at 11:52:18 (all times UTC). An eruption energy release of ~ 3 × 1012 J was calculated using a body wave equation for radiated seismic energy. A similar calculation based on the infrasound record, shows that ~ 90% of the acoustic energy was released from three impulses at onset times 11:52:20 (~ 20% of total eruption energy), 11:52:27 (~ 50%), and 11:52:31 (~ 20%). These energy impulses may coincide with eyewitness accounts describing an initial eastward directed blast, followed by a westward directed blast, and a final vertical blast. Pre-eruption seismic activity includes numerous small unlocatable micro-earthquakes that began at 11:46:50. Two larger high frequency earthquakes were recorded at 11:49:06 and 11:49:21 followed directly by a third earthquake at 11:50:17. The first event was located within the scarp based on an arrival time location from good first P arrival times and probably represents the onset of the debris avalanche. The third event was a tornillo, characterised by a 0.8 Hz single frequency resonance, and has a resonator attenuation factor of Q ~ 40, consistent with a bubbly fluid filled resonator. This contrasts with a similar tornillo event occurring 2.5 weeks earlier having Q ~ 250–1000, consistent with a dusty gas charged resonator. We surmise from pre-eruption seismicity, and the observed attenuation change, that the debris avalanche resulted from the influx of fluids into the hydrothermal system, causing destabilisation and failure. The beheaded hydrothermal system may have then caused depressurisation frothing of the remaining gas charged system leading to the

  19. Salt shell fallout during the ash eruption at the Nakadake crater, Aso volcano, Japan: evidence of an underground hydrothermal system surrounding the erupting vent

    Science.gov (United States)

    Shinohara, Hiroshi; Geshi, Nobuo; Yokoo, Akihiko; Ohkura, Takahiro; Terada, Akihiko

    2018-03-01

    A hot and acid crater lake is located in the Nakadake crater, Aso volcano, Japan. The volume of water in the lake decreases with increasing activity, drying out prior to the magmatic eruptions. Salt-rich materials of various shapes were observed, falling from the volcanic plume during the active periods. In May 2011, salt flakes fell from the gas plume emitted from an intense fumarole when the acid crater lake was almost dry. The chemical composition of these salt flakes was similar to those of the salts formed by the drying of the crater lake waters, suggesting that they originated from the crater lake water. The salt flakes are likely formed by the drying up of the crater lake water droplets sprayed into the plume by the fumarolic gas jet. In late 2014, the crater lake dried completely, followed by the magmatic eruptions with continuous ash eruptions and intermittent Strombolian explosions. Spherical hollow salt shells were observed on several occasions during and shortly after the weak ash eruptions. The chemical composition of the salt shells was similar to the salts formed by the drying of the crater lake water. The hollow structure of the shells suggests that they were formed by the heating of hydrothermal solution droplets suspended by a mixed stream of gas and ash in the plume. The salt shells suggest the existence of a hydrothermal system beneath the crater floor, even during the course of magmatic eruptions. Instability of the magmatic-hydrothermal interface can cause phreatomagmatic explosions, which often occur at the end of the eruptive phase of this volcano.

  20. Magnetohydrodynamic interpretation of the motion of prominences

    International Nuclear Information System (INIS)

    Sakurai, Takashi

    1976-01-01

    We study three types of prominence eruptions, which we will call the arch type, the loop type, and the gigantic arch type, respectively, from their shapes. If we regard the prominence as a magnetic flux tube, the onset of its ascending motion can be interpreted as the motion due to the screw-mode instability, which is the most unstable mode of instabilities of a magnetofluid column (pinch). The growth rate of this mode is evaluated and is shown to be consistent with the time scale of the initial stage of the eruption. In order to study the nonlinear stage of the instability, we propose a method of numerical calculation based on a variational technique known as Ritz's method. The result shows that the characteristic motion of the arch-, loop-, and gigantic arch-type eruptions may be reproduced by perturbing a model sequence with decreasing pitch angles of the unperturbed helical magnetic field lines. This conclusion seems to be supported by the pitch angles of observed threads in each type of prominence and also by the fact that the observed time profiles of the rising velocity of the prominences of each type agree well with those predicted from model calculations. (auth.)

  1. Two Categories of Apparent Tornado-like Prominences

    Science.gov (United States)

    Martin, Sara F.; Venkataramanasastry, Aparna

    2014-06-01

    Two categories of solar prominences have been described in the literature as having a pattern of mass motions and/or a shape similar to terrestrial tornados. We first identify the two categories associated with prominences in the historic literature and then show that counterparts do exist for both in recent literature but one has not been called a tornado prominence. One category described as being similar to tornados is associated with the barbs of quiescent filaments but barbs appear to have rotational motion only under special conditions. H alpha Doppler observations from Helio Research confirm that this category is an illusion in our mind’s eye resulting from counterstreaming in the large barbs of quiescent filaments. The second category is a special case of rotational motion occurring during the early stages of some erupting prominences, in recent years called the roll effect in erupting prominences. In these cases, the eruption begins with the sideways rolling of the top of a prominence. As the eruption proceeds the rolling motion propagates down one leg or both legs of an erupting prominence depending on whether the eruption is asymmetric or symmetric respectively. As an asymmetric eruption proceeds, the longer lasting leg becomes nearly vertical and has true rotational motion. If only this phase of the eruption was observed, as in the historic cases, it was called a tornado prominence and spectra recorded in these cases provide proof of the rotational motion. When one observes an entire eruption which exhibits the rolling motion, as accomplished at Helio Research, the similarity to a tornado is lost because the event as a whole has quite a different nature and the analogy to a terrestrial tornado not longer appears suitable or helpful in understanding the observed and deduced physical processes. Our conclusion is that there are no solar prominences with motions that are usefully described as tornado or tornado-like events aside from the fun of observing

  2. Subaqueous early eruptive phase of the late Aptian Rajmahal volcanism, India: Evidence from volcaniclastic rocks, bentonite, black shales, and oolite

    Directory of Open Access Journals (Sweden)

    Naresh C. Ghose

    2017-07-01

    of grey and black shale/mudstone in the lower one-third of the succession across the entire Rajmahal basin provides unequivocal evidence of a shallow-marine continental shelf-type environment. Alignment of the Rajmahal eruptive centers with a major N–S mid-Neoproterozoic lineament and the presence of a gravity high on the RVP suggest a tectonic control for the eruption of melts associated with the Kerguelen plume that was active in a post-Gondwana rift between India and Australia-Antarctica.

  3. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    International Nuclear Information System (INIS)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam; Gömöry, Peter; Wang, Tongjiang; Gan, Weiqun; Li, YouPing

    2014-01-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s –1

  4. Solar Magnetized Tornadoes: Rotational Motion in a Tornado-like Prominence

    Science.gov (United States)

    Su, Yang; Gömöry, Peter; Veronig, Astrid; Temmer, Manuela; Wang, Tongjiang; Vanninathan, Kamalam; Gan, Weiqun; Li, YouPing

    2014-04-01

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ~5 km s-1.

  5. SOLAR MAGNETIZED TORNADOES: ROTATIONAL MOTION IN A TORNADO-LIKE PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Su, Yang; Veronig, Astrid; Temmer, Manuela; Vanninathan, Kamalam [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Gömöry, Peter [Astronomical Institute of the Slovak Academy of Sciences, SK-05960 Tatranská Lomnica (Slovakia); Wang, Tongjiang [Department of Physics, the Catholic University of America, Washington, DC 20064 (United States); Gan, Weiqun; Li, YouPing, E-mail: yang.su@uni-graz.at [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2014-04-10

    Su et al. proposed a new explanation for filament formation and eruption, where filament barbs are rotating magnetic structures driven by underlying vortices on the surface. Such structures have been noticed as tornado-like prominences when they appear above the limb. They may play a key role as the source of plasma and twist in filaments. However, no observations have successfully distinguished rotational motion of the magnetic structures in tornado-like prominences from other motions such as oscillation and counter-streaming plasma flows. Here we report evidence of rotational motions in a tornado-like prominence. The spectroscopic observations in two coronal lines were obtained from a specifically designed Hinode/EIS observing program. The data revealed the existence of both cold and million-degree-hot plasma in the prominence leg, supporting the so-called prominence-corona transition region. The opposite velocities at the two sides of the prominence and their persistent time evolution, together with the periodic motions evident in SDO/AIA dark structures, indicate a rotational motion of both cold and hot plasma with a speed of ∼5 km s{sup –1}.

  6. Stratigraphy, distribution, and evidence for mafic triggering of the ca. 8.5 ka Driftwood Pumice eruption, Makushin Volcano, Alaska, U.S.A

    Science.gov (United States)

    Lerner, Allan H.; Crowley, Peter D.; Nicolaysen, Kirsten P.; Hazlett, Richard W.

    2018-05-01

    Makushin Volcano on Unalaska Island, Alaska, threatens the Aleutian's largest population centers (Unalaska and Dutch Harbor), yet its eruption mechanisms are poorly known. This study presents a detailed stratigraphic and geochemical investigation of Makushin's most recent highly explosive event: the ca. 8.5 ka Driftwood Pumice eruption. The Driftwood Pumice has measured thicknesses of over 2.5 m, and isopach reconstructions estimate a total deposit volume of 0.3 to 1.6 km3, indicating a VEI 4-5 eruption. Proximal deposits consist of normally-graded, tan, dacitic to andesitic pumice, capped by a thinner dark layer of lower-silica andesitic scoria mixed with abundant lithic fragments. This stratigraphy is interpreted as an initial vent-clearing eruption that strengthened into a climactic ejection of pumice and ash and concluded with vent destabilization and the eruption of somewhat more mafic, gas-poor magma. Within the pumice, geochemical trends, disequilibrium mineral populations, and mineral zonation patterns show evidence of magma mixing between a bulk silicic magma and a mafic melt. Euhedral high-Ca plagioclase (An68-91) and high-Mg olivine (Fo69-77) phenocrysts are in disequilibrium with trachydacitic glass (65-68 wt% SiO2) and more abundant sodic plagioclase (An34-55), indicating the former originally crystallized in a more mafic melt. Tephra whole rock compositions become more mafic upwards through the deposit, ranging from a basal low-silica dacite to an andesite (total range: 60.8-63.3 wt% SiO2). Collectively, these compositional variations suggest magma mixing in the Driftwood Pumice (DWP) magma reservoir, with a systematic increase in the amount of a mafic component (up to 25%) upward through the deposit. Olivine-liquid and liquid-only thermometry indicate the mafic magma intruded at temperatures 140-200 °C hotter than the silicic magma. Diffusion rates calculated for 5-7 μm thick, lower-Mg rims on the olivine phenocrysts (Fo60 rim vs Fo76 bulk) suggest

  7. Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae: evidence for a prominent central olfactory pathway?

    Directory of Open Access Journals (Sweden)

    Krieger Jakob

    2010-09-01

    Full Text Available Abstract Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae, is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the neuropil volume in its brain. The paired olfactory neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side associated with the hemiellipsoid neuropils. The hemiellipsoid body neuropil is organized into parallel neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic neuropils and areas associated with antenna two

  8. HELICAL MOTIONS OF FINE-STRUCTURE PROMINENCE THREADS OBSERVED BY HINODE AND IRIS

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Takenori J. [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Liu, Wei [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Tsuneta, Saku, E-mail: joten.okamoto@nao.ac.jp [ISAS/JAXA, Sagamihara, Kanagawa 252-5210 (Japan)

    2016-11-10

    Fine-structure dynamics in solar prominences holds critical clues to understanding their physical nature of significant space-weather implications. We report evidence of rotational motions of horizontal helical threads in two active-region prominences observed by the Hinode and/or Interface Region Imaging Spectrograph satellites at high resolution. In the first event, we found transverse motions of brightening threads at speeds up to 55 km s{sup -1} seen in the plane of the sky. Such motions appeared as sinusoidal space–time trajectories with a typical period of ∼390 s, which is consistent with plane-of-sky projections of rotational motions. Phase delays at different locations suggest the propagation of twists along the threads at phase speeds of 90–270 km s{sup -1}. At least 15 episodes of such motions occurred in two days, none associated with an eruption. For these episodes, the plane-of-sky speed is linearly correlated with the vertical travel distance, suggestive of a constant angular speed. In the second event, we found Doppler velocities of 30–40 km s{sup -1} in opposite directions in the top and bottom portions of the prominence, comparable to the plane-of-sky speed. The moving threads have about twice broader line widths than stationary threads. These observations, when taken together, provide strong evidence for rotations of helical prominence threads, which were likely driven by unwinding twists triggered by magnetic reconnection between twisted prominence magnetic fields and ambient coronal fields.

  9. H(alpha) Proxies for EIT Crinkles: Further Evidence for Preflare "Breakout"-Type Activity in an Ejective Solar Eruption

    Science.gov (United States)

    Sterling, Alphonse C.; Qiu, Jiong; Wang, Haimin; Moore, Ronald L.

    2001-01-01

    We present H(alpha) observations from Big Bear Solar Observatory of an eruptive flare in NOAA Active Region 8210, occurring near 22:30 UT on 1998 May 1. Previously, using the Extreme Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) spacecraft, we found that a pattern of transient, localized brightenings, which we call 'EIT crinkles,' appears in the neighborhood of the eruption near the time of flare onset. These EIT crinkles occur at a location in the active region well separated from the sheared core magnetic fields, which is where the most intense features of the eruption are concentrated. We also previously found that high-cadence images from the Soft X-ray Telescope (SXT) on Yohkoh indicate that soft X-ray intensity enhancements in the core begin after the start of the EIT crinkles. With the H(alpha) data, we find remote flare brightening counterparts to the EIT crinkles. Light curves as functions of time of various areas of the active region show that several of the remote flare brightenings undergo intensity increases prior to the onset of principal brightenings in the core region, consistent with our earlier findings from EIT and SXT data. These timing relationships are consistent with the eruption onset mechanism known as the breakout model, introduced by Antiochos and colleagues, which proposes that eruptions begin with reconnection at a magnetic null high above the core region. Our observations are also consistent with other proposed mechanisms that do not involve early reconnection in the core region. As a corollary, our observations are not consistent with the so-called tether-cutting models, which say that the eruption begins with reconnection in the core. The H(alpha) data further show that a filament in the core region becomes activated near the time of EIT crinkle onset, but little if any of the filament actually erupts, despite the presence of a halo coronal mass ejection (CME) associated with this event.

  10. Prominence mass supply and the cavity

    Energy Technology Data Exchange (ETDEWEB)

    Schmit, Donald J.; Innes, D. [Max Planck Institute for Solar System Research, D-37191 Katlenburg-Lindau (Germany); Gibson, S. [High Altitude Observatory, National Center for Atmospheric Research, Boulder, CO 80307 (United States); Luna, M. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Karpen, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-12-20

    A prevalent but untested paradigm is often used to describe the prominence-cavity system: the cavity is under-dense because it is evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolution of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model with diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prominence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 Å bandpass near the prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of our one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  11. Prominence Mass Supply and the Cavity

    Science.gov (United States)

    Schmit, Donald J.; Gibson, S.; Luna, M.; Karpen, J.; Innes, D.

    2013-01-01

    A prevalent but untested paradigm is often used to describe the prominence-cavity system; the cavity is under-dense because it it evacuated by supplying mass to the condensed prominence. The thermal non-equilibrium (TNE) model of prominence formation offers a theoretical framework to predict the thermodynamic evolutin of the prominence and the surrounding corona. We examine the evidence for a prominence-cavity connection by comparing the TNE model and diagnostics of dynamic extreme ultraviolet (EUV) emission surrounding the prominence, specifically prominence horns. Horns are correlated extensions of prminence plasma and coronal plasma which appear to connect the prominence and cavity. The TNE model predicts that large-scale brightenings will occur in the Solar Dynamics Observatory Atmospheric Imaging Assembly 171 A badpass near he prominence that are associated with the cooling phase of condensation formation. In our simulations, variations in the magnitude of footpoint heating lead to variations in the duration, spatial scale, and temporal offset between emission enhancements in the other EUV bandpasses. While these predictions match well a subset of the horn observations, the range of variations in the observed structures is not captured by the model. We discuss the implications of one-dimensional loop simulations for the three-dimensional time-averaged equilibrium in the prominence and the cavity. Evidence suggests that horns are likely caused by condensing prominence plasma, but the larger question of whether this process produces a density-depleted cavity requires a more tightly constrained model of heating and better knowledge of the associated magnetic structure.

  12. Brandburg Prominance, Namibia, Africa

    Science.gov (United States)

    1993-01-01

    The Brandburg Prominance, Namibia (21.0S, 14.5E) is a round basaltic plug and is the highest feature (over 8,000 ft) in the country. Wind streaks on the surface of the coastal desert, aligned northeast to southwest, are the result of frequent sand storms. Coastal stratus clouds provide most of the life supporting moisture as fog droplets in this arid land where annual rainfall may be less than a quarter of an inch for decades at a time.

  13. Chlorine as a geobarometer for alkaline magmas: Evidence from a systematic study of the eruptions of Mount Somma-Vesuvius

    Science.gov (United States)

    Balcone-Boissard, H.; Boudon, G.; Cioni, R.; Webster, J. D.; Zdanowicz, G.; Orsi, G.; Civetta, L.

    2016-02-01

    Defining the magma storage conditions of a volcanic system is a major goal in modern volcanology due to its direct implications for the style of a possible eruption, and thus on the associated risk of any crisis and the necessary management and mitigation strategies. Below 200 MPa and at equivalent depths, the strongly non-ideal behaviour of the H-C-O-S-Cl-F system in the silicate melt causes unmixing of the fluid phase to form an H2O-rich vapour and a hydrosaline phase in equilibrium with the silicate melt, both responsible for buffering the chlorine (Cl) concentration. Following this equilibrium, the Cl concentration in melts may be used as a geobarometer for alkaline magmas. Systematic application of this method to the main explosive eruptions of Mount Somma-Vesuvius highlights two main magma ponding zones, at ~180-200 and ~100 MPa. At these pressures, the maximum pre-eruptive H2O contents for the different magma compositions can be estimated; the results obtained, largely in agreement with the current literature, therefore confirm the validity of the method. The Cl geobarometer may help scientists to define the variation of the magmatic reservoir location through time and thus provide strong constraints on pre-eruptive conditions, which are of utmost importance for volcanic crisis management.

  14. Evidence of Influence of Human Activities and Volcanic Eruptions on Environmental Perchlorate from a 300-Year Greenland Ice Core Record.

    Science.gov (United States)

    Cole-Dai, Jihong; Peterson, Kari Marie; Kennedy, Joshua Andrew; Cox, Thomas S; Ferris, David G

    2018-06-26

    A 300-year (1700-2007) chronological record of environmental perchlorate, reconstructed from high-resolution analysis of a central Greenland ice core, shows that perchlorate levels in the post-1980 atmosphere were two-to-three times those of the pre-1980 environment. While this confirms recent reports of increased perchlorate in Arctic snow since 1980 compared with the levels for the prior decades (1930-1980), the longer Greenland record demonstrates that the Industrial Revolution and other human activities, which emitted large quantities of pollutants and contaminants, did not significantly impact environmental perchlorate, as perchlorate levels remained stable throughout the eighteenth, nineteenth, and much of the twentieth centuries. The increased levels since 1980 likely result from enhanced atmospheric perchlorate production, rather than from direct release from perchlorate manufacturing and applications. The enhancement is probably influenced by the emission of organic chlorine compounds in the last several decades. Prior to 1980, no significant long-term temporal trends in perchlorate concentration are observed. Brief (a few years) high concentration episodes appear frequently over an apparently stable and low background (~1 ng kg‒1). Several such episodes coincide in time with large explosive volcanic eruptions including the 1912 Novarupta/Katmai eruption in Alaska. It appears that atmospheric perchlorate production is impacted by large eruptions in both high and low latitudes, but not by small eruptions and non-explosive degassing.

  15. Formation and support of prominence

    International Nuclear Information System (INIS)

    Forbes, T.G.

    1986-01-01

    A short introduction is given to the concepts discussed by the group on the formation and support of prominences. Only quiescent and long-lived active region prominences were considered, since transient prominence phenomena, such as sprays, surges, H alpha flare-loops, and coronal rain, are dynamically distinct from long-lived, prominences. Stable prominences (which are often referred to as filaments when seen against the disk) can be subdivided into three categories, namely active region prominences, quiescent prominences and polar crown prominences. The third category is closely related to the second since a quiescent prominence will eventually evolve into a polar crown prominence if it lasts long enough. The distinction between the first and second categories is not sharp either since intermediates exist here as well (Martin, 1973)

  16. The 21,700 yr b.p. Lower Toluca Pumice Plinian Eruption of Nevado de Toluca Volcano (Mexico): Evidences of Magma Mixing Process as Triggering Mechanism.

    Science.gov (United States)

    Capra, L.; Arce, J.; Macias, J.

    2006-05-01

    Approximately 21,700 yr B.P., after a period of quiescence of 4800 yr, Nevado de Toluca volcano erupted, producing the Lower Toluca Pumice deposit. The activity generated a 24-km-high Plinian column that lasted ~11 h and dispersed 2.3 km3 (0.8 km3 dense rock equivalent) of tephra toward the NE, blanketing the Lerma basin, an area occupied today by the city of Toluca, with up to 5 cm of ash. Subsequent eruptive pulses were sub-Plinian in style, accompanied by phreatomagmatic explosions that emplaced surge deposits. Finally, the column collapsed toward the NE with the emplacement of a pumice flow deposit. The high vesicularity of the pumice from the basal Plinian layer, up to 83% by volume, indicates that exsolution was dominantly magmatic, and that pressurization of the magma chamber was probably due to a magma mixing process. Evidence for this includes the compositional range of juvenile products (from 55 to 65 wt% SiO2), as well as the presence of two types of plagioclase, one in equilibrium and the other one with disequilibrium textures and reverse zoning. This suggests input of an andesitic liquid into the dacitic magma chamber. Based on the eruptive record, the most likely future eruptive activity at Nevado de Toluca volcano will be Plinian. Although quiet for more than 3250 yr, Plinian activity could occur after a long period of quiescence, and it could represent a hazard for the entire Toluca basin, where more than one million people live today.

  17. Eruption Depths, Magma Storage and Magma Degassing at Sumisu Caldera, Izu-Bonin Arc: Evidence from Glasses and Melt Inclusions

    Science.gov (United States)

    Johnson, E. R.

    2015-12-01

    Island arc volcanoes can become submarine during cataclysmal caldera collapse. The passage of a volcanic vent from atmospheric to under water environment involves complex modifications of the eruption style and subsequent transport of the pyroclasts. Here, we use FTIR measurements of the volatile contents of glass and melt inclusions in the juvenile pumice clasts in the Sumisu basin and its surroundings (Izu-Bonin arc) to investigate changes in eruption depths, magma storage and degassing over time. This study is based on legacy cores from ODP 126, where numerous unconsolidated (250 m), massive to normally graded pumice lapilli-tuffs were recovered over four cores (788C, 790A, 790B and 791A). Glass and clast geochemistry indicate the submarine Sumisu caldera as the source of several of these pumice lapilli-tuffs. Glass chips and melt inclusions from these samples were analyzed using FTIR for H2O and CO2 contents. Glass chips record variable H2O contents; most chips contain 0.6-1.6 wt% H2O, corresponding to eruption depths of 320-2100 mbsl. Variations in glass H2O and pressure estimates suggest that edifice collapse occurred prior-to or during eruption of the oldest of these samples, and that the edifice may have subsequently grown over time. Sanidine-hosted melt inclusions from two units record variably degassed but H2O-rich melts (1.1-5.6 wt% H2O). The lowest H2O contents overlap with glass chips, consistent with degassing and crystallization of melts until eruption, and the highest H2O contents suggest that large amounts of degassing accompanied likely explosive eruptions. Most inclusions, from both units, contain 2-4 wt% H2O, which further indicates that the magmas crystallized at pressures of ~50-100 MPa, or depths ~400-2800 m below the seafloor. Further glass and melt inclusion analyses, including major element compositions, will elucidate changes in magma storage, degassing and evolution over time.

  18. Nonlinear MHD Waves in a Prominence Foot

    Science.gov (United States)

    Ofman, L.; Knizhnik, K.; Kucera, T.; Schmieder, B.

    2015-11-01

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ˜ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5-11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5-14 G. For the typical prominence density the corresponding fast magnetosonic speed is ˜20 km s-1, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  19. NONLINEAR MHD WAVES IN A PROMINENCE FOOT

    Energy Technology Data Exchange (ETDEWEB)

    Ofman, L. [Catholic University of America, Washington, DC 20064 (United States); Knizhnik, K.; Kucera, T. [NASA Goddard Space Flight Center, Code 671, Greenbelt, MD 20771 (United States); Schmieder, B. [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris-Diderot, Sorbonne Paris Cit, 5 place Jules Janssen, F-92195 Meudon (France)

    2015-11-10

    We study nonlinear waves in a prominence foot using a 2.5D MHD model motivated by recent high-resolution observations with Hinode/Solar Optical Telescope in Ca ii emission of a prominence on 2012 October 10 showing highly dynamic small-scale motions in the prominence material. Observations of Hα intensities and of Doppler shifts show similar propagating fluctuations. However, the optically thick nature of the emission lines inhibits a unique quantitative interpretation in terms of density. Nevertheless, we find evidence of nonlinear wave activity in the prominence foot by examining the relative magnitude of the fluctuation intensity (δI/I ∼ δn/n). The waves are evident as significant density fluctuations that vary with height and apparently travel upward from the chromosphere into the prominence material with quasi-periodic fluctuations with a typical period in the range of 5–11 minutes and wavelengths <2000 km. Recent Doppler shift observations show the transverse displacement of the propagating waves. The magnetic field was measured with the THEMIS instrument and was found to be 5–14 G. For the typical prominence density the corresponding fast magnetosonic speed is ∼20 km s{sup −1}, in qualitative agreement with the propagation speed of the detected waves. The 2.5D MHD numerical model is constrained with the typical parameters of the prominence waves seen in observations. Our numerical results reproduce the nonlinear fast magnetosonic waves and provide strong support for the presence of these waves in the prominence foot. We also explore gravitational MHD oscillations of the heavy prominence foot material supported by dipped magnetic field structure.

  20. Solar Features - Prominences and Filaments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense...

  1. Evidence for degassing of fresh magma during the 2004-2008 eruption of Mount St. Helens: Subtle signals from the hydrothermal system

    Science.gov (United States)

    Bergfeld, Deborah; Evans, William C.; Spicer, Kurt R.; Hunt, Andrew G.; Kelly, Peter

    2017-01-01

    Results from chemical and isotopic analyses of water and gas collected between 2002 and 2016 from sites on and around Mount St. Helens are used to assess magmatic degassing related to the 2004-2008 eruption. During 2005 the chemistry of hot springs in The Breach of Mount St. Helens showed no obvious response to the eruption, and over the next few years, changes were subtle, giving only slight indications of perturbations in the system. By 2010 however, water chemistry, temperatures, and isotope compositions (δD and δ18O) clearly indicated some inputs of volatiles and heat associated with the eruption, but the changes were such that they could be attributed to a pre-existing, gas depleted magma. An increase of ~ 1.5‰ in the δ13C values of dissolved carbon in the springs was noted in 2006 and continued through 2009, a change that was mirrored by a similar shift in δ13C-CO2 in bubble gas emissions. These changes require input of a new source of carbon to the hydrothermal system and provide clear evidence of CO2 from an undegassed body of magma. Rising trends in 3He/4He ratios in gas also accompanied the increases in δ13C. Since 2011 maximum RC/RA values are ≥ 6.4 and are distinctly higher than 5 samples collected between 1986 and 2002, and provide additional evidence for some involvement of new magma as early as 2006, and possibly earlier, given the unknown time needed for CO2 and He to traverse the system and arrive at the springs.

  2. New perspectives on solar prominences

    Science.gov (United States)

    Schmieder, B.; Aulanier, G.

    2012-06-01

    Recent observations of prominences obtained with high spatial and temporal resolution instruments, on board satellites (Hinode, SDO) as well as on the ground (SST) have provided very intriguing movies and open a new area for understanding the nature of prominences. The main topics are still debate: formation, dynamics, and characteristics of the plasma in the core and in the transition zone between the prominence and corona. We will review briefly the recent advances made in these topics, observationally as well as theoretically.

  3. Evidence for large compositional ranges in coeval melts erupted from Kīlauea's summit reservoir: Chapter 7

    Science.gov (United States)

    Helz, Rosalind T.; Clague, David A.; Mastin, Larry G.; Rose, Timothy R.; Carey, Rebecca; Cayol, Valérie; Poland, Michael P.; Weis, Dominique

    2015-01-01

    Petrologic observations on Kīlauea's lavas include abundant microprobe analyses of glasses, which show the range of melts available in Kīlauea's summit reservoir over time. During the past two centuries, compositions of melts erupted within the caldera have been limited to MgO = 6.3–7.5 wt%. Extracaldera lavas of the 1959, 1971, and 1974 eruptions contain melts with up to 10.2, 8.9, and 9.2 wt% MgO, respectively, and the 1924 tephra contains juvenile Pele's tears with up to 9.1 wt% MgO. Melt compositions from explosive deposits at Kīlauea, including the Keanakāko‘i (A.D. 1500–1800), Kulanaokuaiki (A.D. 400–1000), and Pāhala (10–25 ka) tephra units, show large ranges of MgO contents. The range of melt MgO is 6.5–11.0 wt% for the Keanakāko‘i; the Kulanaokuaiki extends to 12.5% MgO and the Pāhala Ash includes rare shards with 13–14.5% MgO. The frequency distributions for MgO in the Keanakāko‘i and Kulanaokuaiki glasses are bimodal, suggesting preferential magma storage at two different depths. Kīlauea's summit reservoir contains melts ranging from 6.5 to at least 11.0 wt% MgO, and such melts were available for sampling near instantaneously and repeatedly over centuries. More magnesian melts are inferred to have risen directly from greater depth.

  4. Physics of solar prominences. Proceedings of the Colloquium, Oslo, Norway, August 14-18, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, E; Maltby, P

    1979-01-01

    These papers deal with recent theoretical and observational studies of the physics of solar prominences. Specific topics include reviews of prominence spectra and their interpretation, polarimetric observations and magnetic-field determination in prominences, observations of the prominence-corona interface, theories on the formation and stability of quiescent prominences, prominence classifications, observations of active prominences, observations and interpretations of coronal manifestations of eruptive prominences, and models of prominence structure and dynamics. Other contributions discuss simultaneous observations of Ca II and hydrogen Balmer lines in quiescent prominences, recent results in quiescent-prominence spectroscopy, the solar helium abundance obtained from optical spectra of quiescent prominences, and Stokes polarimetry of quiescent prominences in the He I D3 line. Magnetic-field determination based on the Hanle effect is also examined, along with the orientation of prominence microstructure relative to magnetic-field direction, radio observations of quiescent-prominence filaments at centimeter and millimeter wavelengths, EUV observations of filaments, and a magnetic-field reconnection model of quiescent prominences.

  5. Textural evidence for high-grade ignimbrites formed by low-explosivity eruptions, Paraná Magmatic Province, southern Brazil

    Science.gov (United States)

    Luchetti, Ana Carolina F.; Gravley, Darren M.; Gualda, Guilherme A. R.; Nardy, Antonio J. R.

    2018-04-01

    The Paraná-Etendeka Province is a Lower Cretaceous huge bimodal tholeiitic volcanic province (1 million·km3) that predated the Gondwana breakup. Its silicic portion makes up a total volume of at least 20,000 km3 and in southern Brazil it comprises the Chapecó porphyritic high-Ti trachydacites-dacites and the Palmas microporphyritic-aphyric low-Ti dacites-rhyolites. The widespread silicic sheets are debated in the literature because they bear similarities between lavas and high grade ignimbrites. Here we provide new observations and interpretations for flow units with large, dark, and vesicle-poor lens-shaped blobs surrounded by a light-colored matrix. The textural features (macro- to micro-scale) of these blobs are different from typical pumice and/or fiamme and support a low explosivity pyroclastic origin, possibly low-column fountain eruptions with discharge rates high enough to produce laterally extensive high-grade ignimbrites. Such an interpretation, combined with a conspicuous absence of lithic fragments in the deposits, is aligned with a lack of identified calderas in the Paraná-Etendeka Province. Maximum timescales of crystallization associated with the juvenile blobs and estimated from CSD slopes are on the order of millennia for phenocryst populations and on the order of decades for microphenocryst populations.

  6. Glacier melting during lava dome growth at Nevado de Toluca volcano (Mexico): Evidences of a major threat before main eruptive phases at ice-caped volcanoes

    Science.gov (United States)

    Capra, L.; Roverato, M.; Groppelli, G.; Caballero, L.; Sulpizio, R.; Norini, G.

    2015-03-01

    Nevado de Toluca volcano is one of the largest stratovolcanoes in the Trans-Mexican Volcanic Belt. During Late Pleistocene its activity was characterized by large dome growth and subsequent collapse emplacing large block and ash flow deposits, intercalated by Plinian eruptions. Morphological and paleoclimate studies at Nevado de Toluca and the surrounding area evidenced that the volcano was affected by extensive glaciation during Late Pleistocene and Holocene. During the older recognized glacial period (27-60 ka, MIS 3), the glacier was disturbed by the intense magmatic and hydrothermal activity related to two dome extrusion episodes (at 37 ka and 28 ka). Glacier reconstruction indicates maximum ice thickness of 90 m along main valleys, as at the Cano ravines, the major glacial valley on the northern slope of the volcano. Along this ravine, both 37 and 28 ka block-and-ash deposits are exposed, and they directly overlay a fluviatile sequence, up to 40 m-thick, which 14C ages clearly indicate that their emplacement occurred just before the dome collapsed. These evidences point to a clear interaction between the growing dome and its hydrothermal system with the glacier. During dome growth, a large amount of melting water was released along major glacial valleys forming thick fluvioglacial sequences that were subsequently covered by the block-and-ash flow deposits generated by the collapse of the growing dome. Even though this scenario is no longer possible at the Nevado de Toluca volcano, the data presented here indicate that special attention should be paid to the possible inundation areas from fluviatile/lahar activity prior to the main magmatic eruption at ice-capped volcanoes.

  7. CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong, E-mail: ymwang@ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2012-01-10

    At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R{sub Sun} from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R{sub Sun} and the second one is 0.19 R{sub Sun }. (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R{sub Sun }. (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

  8. CRITICAL HEIGHT FOR THE DESTABILIZATION OF SOLAR PROMINENCES: STATISTICAL RESULTS FROM STEREO OBSERVATIONS

    International Nuclear Information System (INIS)

    Liu Kai; Wang Yuming; Wang Shui; Shen Chenglong

    2012-01-01

    At which height is a prominence inclined to be unstable, or where is the most probable critical height for the prominence destabilization? This question was statistically studied based on 362 solar limb prominences well recognized by Solar Limb Prominence Catcher and Tracker from 2007 April to the end of 2009. We found that there are about 71% disrupted prominences (DPs), among which about 42% of them did not erupt successfully and about 89% of them experienced a sudden destabilization process. After a comprehensive analysis of the DPs, we discovered the following: (1) Most DPs become unstable at a height of 0.06-0.14 R ☉ from the solar surface, and there are two most probable critical heights at which a prominence is very likely to become unstable, the first one is 0.13 R ☉ and the second one is 0.19 R ☉ . (2) An upper limit for the erupting velocity of eruptive prominences (EPs) exists, which decreases following a power law with increasing height and mass; accordingly, the kinetic energy of EPs has an upper limit too, which decreases as the critical height increases. (3) Stable prominences are generally longer and heavier than DPs, and not higher than 0.4 R ☉ . (4) About 62% of the EPs were associated with coronal mass ejections (CMEs); but there is no difference in apparent properties between EPs associated with CMEs and those that are not.

  9. [Localized eruptive juvenile xanthogranuloma].

    Science.gov (United States)

    Vanotti, S; Chiaverini, C; Rostain, G; Cardot-Leccia, N; Lacour, J-P

    2014-03-01

    Juvenile xanthogranuloma (JXG) is a non-Langerhans histiocytosis of young children characterized by solitary or multiple yellowish cutaneous nodules. Atypical skin lesions such as lichenoid eruptions, and pedunculated, maculopapular, plaque-like or linear lesions have been described. We report a case of eruptive XGJ en plaque in the left leg in an infant. A 13-month-old child presented asymptomatic eruptive, yellowish papules of the leg measuring 5 to 10mm since the age of 2months. There was no cutaneous infiltration between the lesions. Darier's sign was negative. Histological examination confirmed the diagnosis of JXG. The course of the disease comprised a gradual decrease in the number of active lesions with slight residual pigmentation. Our case was suggestive of JXG en plaque. Only 7 cases have been reported in the literature, all appearing before the age of 5months. The lesions corresponded mostly to an asymptomatic erythematous plaque studded with small yellowish/red nodules of variable localisation. Spontaneous involvement was noted in all cases. No systemic involvement was found. Herein we present a unique case of localised multiple JXG without evident clinical infiltrating plaque progressing with self-resolving flares. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. PROMINENCE ACTIVATION BY CORONAL FAST MODE SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Takuya [Department of Astronomy, Kyoto University, Sakyo, Kyoto, 606-8502 (Japan); Asai, Ayumi [Unit of Synergetic Studies for Space, Kyoto University, Yamashina, Kyoto 607-8471 (Japan); Shibata, Kazunari, E-mail: takahashi@kwasan.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607-8471 (Japan)

    2015-03-01

    An X5.4 class flare occurred in active region NOAA11429 on 2012 March 7. The flare was associated with a very fast coronal mass ejection (CME) with a velocity of over 2500 km s{sup −1}. In the images taken with the Solar Terrestrial Relations Observatory-B/COR1, a dome-like disturbance was seen to detach from an expanding CME bubble and propagated further. A Type-II radio burst was also observed at the same time. On the other hand, in extreme ultraviolet images obtained by the Solar Dynamic Observatory/Atmospheric Imaging Assembly (AIA), the expanding dome-like structure and its footprint propagating to the north were observed. The footprint propagated with an average speed of about 670 km s{sup −1} and hit a prominence located at the north pole and activated it. During the activation, the prominence was strongly brightened. On the basis of some observational evidence, we concluded that the footprint in AIA images and the ones in COR1 images are the same, that is, the MHD fast mode shock front. With the help of a linear theory, the fast mode Mach number of the coronal shock is estimated to be between 1.11 and 1.29 using the initial velocity of the activated prominence. Also, the plasma compression ratio of the shock is enhanced to be between 1.18 and 2.11 in the prominence material, which we consider to be the reason for the strong brightening of the activated prominence. The applicability of linear theory to the shock problem is tested with a nonlinear MHD simulation.

  11. The 1994-2001 eruptive period at Rabaul, Papua New Guinea: Petrological and geochemical evidence for basalt injections into a shallow dacite magma reservoir, and significant SO2 flux

    Science.gov (United States)

    Patia, H.; Eggins, S. M.; Arculus, R. J.; McKee, C. O.; Johnson, R. W.; Bradney, A.

    2017-10-01

    The eruptions that began at Rabaul Caldera on 19 September 1994 had two focal points, the vents Tavurvur and Vulcan, located 6 km apart on opposing sides of the caldera. Vulcan eruptives define a tight cluster of dacite compositions, whereas Tavurvur eruptives span an array from equivalent dacite compositions to mafic andesites. The eruption of geochemically and mineralogically identical dacites from both vents indicates sourcing from the same magma reservoir. This, together with previously reported H2O-CO2 volatile contents of dacite melt inclusions, a caldera-wide seismic low-velocity zone, and a seismically active caldera ring fault structure are consistent with the presence at 3-6 km depth of an extensive, tabular dacitic magma body having volume of about 15-150 km3. The Tavurvur andesites form a linear compositional array and have strongly bimodal phenocryst assemblages that reflect dacite hybridisation with a mafic basalt. The moderately large volume SO2 flux documented in the Tavurvur volcanic plume (and negligible SO2 flux in the Vulcan plume) combined with high dissolved S contents of basaltic melt inclusions trapped in olivine of Tavurvur eruptives, indicate that the amount of degassed basaltic magma was 0.1 km3 and suggest that the injection of this magma was confined to the Tavurvur-side (eastern to northeastern sector) of the caldera. Circumstantial evidence suggests that the eruption was triggered and evolved in response to a series of basaltic magma injections that may have commenced in 1971 and continued up until at least the start of the 1994 eruptions. The presence of zoned plagioclase phenocrysts reflecting older basalt-dacite interaction events (i.e. anorthite cores overgrown with thick andesine rims), evaluation of limited available data for the products of previous eruptions in 1878 and 1937-1943, and the episodic occurrence of major intra-caldera seismo-deformational events indicates that the shallow magma system at Rabaul Caldera is

  12. Neutral Atom Diffusion in a Partially Ionized Prominence Plasma

    Science.gov (United States)

    Gilbert, Holly

    2010-01-01

    The support of solar prominences is normally described in terms of a magnetic force on the prominence plasma that balances the solar gravitational force. Because the prominence plasma is only partially ionized. it is necessary to consider in addition the support of the neutral component of the prominence plasma. This support is accomplished through a frictional interaction between the neutral and ionized components of the plasma, and its efficacy depends strongly on the degree of ionization of the plasma. More specifically, the frictional force is proportional to the relative flow of neutral and ion species, and for a sufficiently weakly ionized plasma, this flow must be relatively large to produce a frictional force that balances gravity. A large relative flow, of course, implies significant draining of neutral particles from the prominence. We evaluate the importance of this draining effect for a hydrogen-helium plasma, and consider the observational evidence for cross-field diffusion of neutral prominence material,

  13. The most prominent safety guarantees

    International Nuclear Information System (INIS)

    Lucenet, G.

    1978-01-01

    The Creys-Malville Nuclear Centre has been designed using the safety analysis implemented since the beginning of the developments of breeder reactors in France and the Super Phenix follows almost the same safety regulations as its predecessor the Phenix reactor. These regulations are based on: 'Recommendations for the safety standards of the Super Phenix' drawn up by the French Safety Authorities in July 1973. The prominent points are summarised. (C.F.)

  14. SOLAR ERUPTION AND LOCAL MAGNETIC PARAMETERS

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeongwoo; Chae, Jongchul [Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of); Liu, Chang; Jing, Ju [Space Weather Research Laboratory, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2016-11-10

    It is now a common practice to use local magnetic parameters such as magnetic decay index for explaining solar eruptions from active regions, but there can be an alternative view that the global properties of the source region should be counted as a more important factor. We discuss this issue based on Solar Dynamics Observatory observations of the three successive eruptions within 1.5 hr from the NOAA active region 11444 and the magnetic parameters calculated using the nonlinear force-free field model. Two violent eruptions occurred in the regions with relatively high magnetic twist number (0.5–1.5) and high decay index (0.9–1.1) at the nominal height of the filament (12″) and otherwise a mild eruption occurred, which supports the local-parameter paradigm. Our main point is that the time sequence of the eruptions did not go with these parameters. It is argued that an additional factor, in the form of stabilizing force, should operate to determine the onset of the first eruption and temporal behaviors of subsequent eruptions. As supporting evidence, we report that the heating and fast plasma flow continuing for a timescale of an hour was the direct cause for the first eruption and that the unidirectional propagation of the disturbance determined the timing of subsequent eruptions. Both of these factors are associated with the overall magnetic structure rather than local magnetic properties of the active region.

  15. The 2014-15 eruption and the short-term geochemical evolution of the Fogo volcano (Cape Verde): Evidence for small-scale mantle heterogeneity

    Science.gov (United States)

    Mata, J.; Martins, S.; Mattielli, N.; Madeira, J.; Faria, B.; Ramalho, R. S.; Silva, P.; Moreira, M.; Caldeira, R.; Moreira, M.; Rodrigues, J.; Martins, L.

    2017-09-01

    Recurrent eruptions at very active ocean island volcanoes provide the ideal means to gain insight on the scale of spatial variations at the mantle source and on temporal changes of magma genesis and evolution processes. In 2014, after 19 years of quiescence, Fogo volcano (Cape Verde Archipelago) experienced a new eruption, with the vents located 200 m from those of the 1995 eruption, and less than 2000 m from those of the 1951 event. This offered a unique opportunity to investigate the existence of small-scale mantle heterogeneities and the short-term compositional evolution of magmas erupted by a very active oceanic volcano like Fogo. Here we present petrological and geochemical data from the early stages of the Fogo's most recent eruption - started on November 23, 2014 - and compare them with the signature of previous eruptions (particularly those of 1995 and 1951). The magmas erupted in 2014 are alkaline (up to 23.4% and 0.94% of normative ne and lc, respectively) with somewhat evolved compositions (Mg # < 56), ranging from tephrites to phonotephrites. The eruption of phonotephritic lavas preceded the effusion of tephritic ones. Lavas carried to the surface clinopyroxene and kaersutite phenocrysts and cognate megacrysts, which indicate that the main stages of magma evolution occurred in magma chambers most probably located at mantle depths (25.6 ± 5.5 km below sea level). This was followed by a shallower (< 1.5 km below sea level) and shorter (≈ 50 days) magma stagnation before the eruption. 2014 magmas have more unradiogenic Sr and more radiogenic Nd compositions than those of the previous 1951 and 1995 eruptions, which generally have less radiogenic Pb ratios. These isotopic differences - coming from quasi-coeval materials erupted almost in the same place - are remarkable and reflect the small-scale heterogeneity of the underlying mantle source. Moreover, they reflect the limited isotopic averaging of the source composition during partial melting events as

  16. Can rain cause volcanic eruptions?

    Science.gov (United States)

    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.

  17. H-alpha Proxies for EIT Crinkles: Further Evidence for Pre-Flare "Breakout"-Type Activity in an Ejective Solar Eruption

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, R. L.; Qiu, J.; Wang, H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    We present Halpha observations from Big Bear Solar Observatory of an eruptive flare in NOAA AR 8210, occurring near 22:30 UT on 1998 May 1. Previously, using the EUV Imaging Telescope (EIT) on the SOHO spacecraft, we found that a pattern of transient, localized brightenings, which we call "EIT crinkles," appears in the neighborhood of the eruption near the time of flare onset. These EIT crinkles occur at a location in the active region well separated from the sheared core magnetic fields, which is where the most intense features of the eruption are concentrated. We also previously found that high-cadence images from the Soft X-ray Telescope (SXT) on Yohkoh indicate that soft X-ray intensity enhancements in the core begin after the start of the EIT crinkles. With the Halpha data, we find remote flare brightening counterparts to the EIT crinkles. Lightcurves as functions of time of various areas of the active region show that several of the remote flare brightenings undergo intensity increases prior to onset of principle brightenings in the core region, consistent with our earlier findings from EIT and SXT data. These timing relationships are consistent with the eruption onset mechanism known as the breakout model, introduced by Antiochos and colleagues, which proposes that eruptions begin with reconnection at a magnetic null high above the core region. Our observations are also consistent with other proposed mechanisms which do not involve early reconnection in the core region. As a corollary, our observations are not consistent with the so-called tether cutting models, which say that the eruption begins with reconnection in the core. The Halpha data further show that a filament in the core region becomes activated near the time of EIT crinkle onset, but little if any of the filament actually erupts, despite the presence of a halo Coronal Mass Ejection (CME) associated with this event.

  18. Will Teide erupt again?

    Science.gov (United States)

    Marti, Joan; Geyer, Adelina

    2016-04-01

    The quantification of hazard in volcanic systems characterised by long repose period is difficult because the lack of knowledge of the past volcanic history and also because in many cases volcanism is not perceived as a potential problem, being only regarded as an attraction for tourism or a source of economic benefit, thus hiding the need to conduct hazard assessment. Teide, in the island of Tenerife (Canary Islands), is not an exception to this general rule and, despite being one of the largest composite volcanoes in the World, it is generally considered as a non-active volcano by population, visitors and even by some scientists. However, geological and geophysical evidence, including a large diversity of monitoring signals recorded during last decades, as well as a simple comparison with similar volcanoes that have erupted in recent times after hundreds or even thousands of years of quiescence, recommend to consider Teide as an active volcano and to take the necessary precaution in an island with nearly one million of permanent inhabitants and nearly 5 millions of visitors per year. What is the potential of Teide to erupt again? is the question that relies behind the fact of considering it as active, and that needs to be answered first. Based on the current volcanological, petrological and geophysical knowledge We propose a conceptual model on the magma recharge mechanisms, structure of the plumbing system, and eruption triggers and dynamics of Teide volcano that helps to understand its behaviour and to anticipate future activity. Ramón y Cajal contract (RYC-2012-11024)

  19. Inherited retarded eruption in the permanent dentition.

    Science.gov (United States)

    Rasmussen, P; Kotsaki, A

    1997-01-01

    The term retarded eruption, may be used in cases where eruption is inhibited, causing an interruption in the coordination of tooth formation and tooth eruption. The phenomenon may be local or general, and several etiological factors for retarded eruption have been listed, comprising a lack of space, ankylosis, cysts, supernumerary teeth, hormone and vitamin deficiencies and several developmental disturbances and syndromes. The present paper describes several cases of retarded eruption where no factors other than inheritance have been evident. So far 14 cases have been evaluated, 9 boys and 5 girls. In addition several cases have been registered among parents and grandparents of the probands. Typical features are: retarded eruption, defined as more than 3 SD beyond mean eruption figures, comprises all teeth in the permanent dentition, and in 5 cases also second primary molars. The chronology of tooth formation are within normal limits. Consequently the teeth finish development still laying deeply buried in the jaws, often in aberrant positions and with curves or hooks on the roots. When the teeth finally get the "signal" for eruption, 5-15 years beyond normal eruption time, they move rather quickly into right positions, despite the long eruption paths and the hooked roots. Permanent teeth without, as well as with predecessors, are affected. Extraction of predecessors does not seem to provoke eruption. The main features in management are to take care of the primary teeth, to improve-esthetics, and offer surgery and orthodontics when needed. Analyses of pedigrees indicates that the genetic transmittance may be autosomal dominant as both sexes are affected, about half of the siblings show the trait, and the trait shows continuity through generations.

  20. Volatile-induced magma differentiation in the plumbing system of Mt. Etna volcano (Italy): evidence from glass in tephra of the 2001 eruption

    Science.gov (United States)

    Ferlito, Carmelo; Viccaro, Marco; Cristofolini, Renato

    2008-02-01

    Mount Etna volcano was shaken during the summer 2001 by one of the most singular eruptive episodes of the last centuries. For about 3 weeks, several eruptive fractures developed, emitting lava flows and tephra that significantly modified the landscape of the southern flank of the volcano. This event stimulated the attention of the scientific community especially for the simultaneous emission of petrologically distinct magmas, recognized as coming from different segments of the plumbing system. A stratigraphically controlled sampling of tephra layers was performed at the most active vents of the eruption, in particular at the 2,100 m (CAL) and at the 2,550 m (LAG) scoria cones. Detailed scanning electron microscope and energy dispersive x-ray spectrometer (SEM-EDS) analyses performed on glasses found in tephra and comparison with lava whole rock compositions indicate an anomalous increase in Ti, Fe, P, and particularly of K and Cl in the upper layers of the LAG sequence. Mass balance and thermodynamic calculations have shown that this enrichment cannot be accounted for by “classical” differentiation processes, such as crystal fractionation and magma mixing. The analysis of petrological features of the magmas involved in the event, integrated with the volcanological evolution, has evidenced the role played by volatiles in controlling the magmatic evolution within the crustal portion of the plumbing system. Volatiles, constituted of H2O, CO2, and Cl-complexes, originated from a deeply seated magma body (DBM). Their upward migration occurred through a fracture network possibly developed by the seismic swarms during the period preceding the event. In the upper portion of the plumbing system, a shallower residing magma body (ABT) had chemical and physical conditions to receive migrating volatiles, which hence dissolved the mobilized elements producing the observed selective enrichment. This volatile-induced differentiation involved exclusively the lowest erupted

  1. Human responses to the 1906 eruption of Vesuvius, southern Italy

    Science.gov (United States)

    Chester, David; Duncan, Angus; Kilburn, Christopher; Sangster, Heather; Solana, Carmen

    2015-04-01

    Cultural and political contexts are important in determining the ways in which communities respond to volcanic eruptions. Understanding the manner in which communities and the State apparatus have coped with historic eruptions can provide insights into how responses have influenced vulnerability and resilience. The 1906 eruption of Vesuvius is well suited for such a study as it was one of the first major eruptions in which there was a significant element of State control, and this worked alongside more traditional pre-industrial responses. This eruption was extensively reported in the regional, national and international press and in archives which include still photography. One feature is the rich archive of material published in English language newspapers of record which are analysed fully in the paper for the first time. Many of these data sources are now accessible on-line. The eruption started on April 4th with mild explosive activity and the eruption of lava from 5th to 7th April. On the night of the 7th/8th, activity intensified when a vigorous lava fountain inclined obliquely to the north east, deposited a thick layer of tephra on the towns of Ottaviano and San Giuseppe. This led to roof collapse and a large number of fatalities. There was increased lava emission and a flow progressed south through the outskirts of Boscotrecase cutting the Circumvesuviana railway line and almost reaching Torre Annunziata. Following April 8th the eruption declined and ended on April 21st. In the initial responses to the eruption pre-industrial features were prominent, with the local communities showing social cohesion, self-reliance and little panic. A more negative aspect was the traditional religious response that involved the use of liturgies of divine appeasement and which included the use of saintly relics and images. There is interesting evidence, however, that this coping strategy was driven by the populace rather than by the clergy. The inhabitants of San Giuseppe

  2. Mechanism of human tooth eruption

    DEFF Research Database (Denmark)

    Kjær, Inger

    2014-01-01

    Human eruption is a unique developmental process in the organism. The aetiology or the mechanism behind eruption has never been fully understood and the scientific literature in the field is extremely sparse. Human and animal tissues provide different possibilities for eruption analyses, briefly ...... keeps this new theory in mind. Understanding the aetiology of the eruption process is necessary for treating deviant eruption courses....... to insight into the aetiology behind eruption. A new theory on the eruption mechanism is presented. Accordingly, the mechanism of eruption depends on the correlation between space in the eruption course, created by the crown follicle, eruption pressure triggered by innervation in the apical root membrane......, and the ability of the periodontal ligament to adapt to eruptive movements. Animal studies and studies on normal and pathological eruption in humans can support and explain different aspects in the new theory. The eruption mechanism still needs elucidation and the paper recommends that future research on eruption...

  3. ARE GIANT TORNADOES THE LEGS OF SOLAR PROMINENCES?

    Energy Technology Data Exchange (ETDEWEB)

    Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Antolin, Patrick, E-mail: sven.wedemeyer@astro.uio.no [Centre for Mathematical Plasma Astrophysics, Department of Mathematics, KU Leuven, Celestijnenlaan 200B, bus 2400, B-3001 Leuven (Belgium)

    2013-09-10

    Observations in the 171 A channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional H{alpha} observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale.

  4. ARE GIANT TORNADOES THE LEGS OF SOLAR PROMINENCES?

    International Nuclear Information System (INIS)

    Wedemeyer, Sven; Scullion, Eamon; Rouppe van der Voort, Luc; Bosnjak, Antonija; Antolin, Patrick

    2013-01-01

    Observations in the 171 Å channel of the Atmospheric Imaging Assembly of the space-borne Solar Dynamics Observatory show tornado-like features in the atmosphere of the Sun. These giant tornadoes appear as dark, elongated, and apparently rotating structures in front of a brighter background. This phenomenon is thought to be produced by rotating magnetic field structures that extend throughout the atmosphere. We characterize giant tornadoes through a statistical analysis of properties such as spatial distribution, lifetimes, and sizes. A total number of 201 giant tornadoes are detected in a period of 25 days, suggesting that, on average, about 30 events are present across the whole Sun at a time close to solar maximum. Most tornadoes appear in groups and seem to form the legs of prominences, thus serving as plasma sources/sinks. Additional Hα observations with the Swedish 1 m Solar Telescope imply that giant tornadoes rotate as a structure, although they clearly exhibit a thread-like structure. We observe tornado groups that grow prior to the eruption of the connected prominence. The rotation of the tornadoes may progressively twist the magnetic structure of the prominence until it becomes unstable and erupts. Finally, we investigate the potential relation of giant tornadoes to other phenomena, which may also be produced by rotating magnetic field structures. A comparison to cyclones, magnetic tornadoes, and spicules implies that such events are more abundant and short-lived the smaller they are. This comparison might help to construct a power law for the effective atmospheric heating contribution as a function of spatial scale

  5. An Eruption on Io

    Science.gov (United States)

    2007-01-01

    The first images returned to Earth by New Horizons during its close encounter with Jupiter feature the Galilean moon Io, snapped with the Long Range Reconnaissance Imager (LORRI) at 0840 UTC on February 26, while the moon was 2.5 million miles (4 million kilometers) from the spacecraft. Io is intensely heated by its tidal interaction with Jupiter and is thus extremely volcanically active. That activity is evident in these images, which reveal an enormous dust plume, more than 150 miles high, erupting from the volcano Tvashtar. The plume appears as an umbrella-shaped feature of the edge of Io's disk in the 11 o'clock position in the right image, which is a long-exposure (20-millisecond) frame designed specifically to look for plumes like this. The bright spots at 2 o'clock are high mountains catching the setting sun; beyond them the night side of Io can be seen, faintly illuminated by light reflected from Jupiter itself. The left image is a shorter exposure -- 3 milliseconds -- designed to look at surface features. In this frame, the Tvashtar volcano shows as a dark spot, also at 11 o'clock, surrounded by a large dark ring, where an area larger than Texas has been covered by fallout from the giant eruption. This is the clearest view yet of a plume from Tvashtar, one of Io's most active volcanoes. Ground-based telescopes and the Galileo Jupiter orbiter first spotted volcanic heat radiation from Tvashtar in November 1999, and the Cassini spacecraft saw a large plume when it flew past Jupiter in December 2000. The Keck telescope in Hawaii picked up renewed heat radiation from Tvashtar in spring 2006, and just two weeks ago the Hubble Space Telescope saw the Tvashtar plume in ultraviolet images designed to support the New Horizons flyby. Most of those images will be stored onboard the spacecraft for downlink to Earth in March and April.

  6. Linking rapid magma reservoir assembly and eruption trigger mechanisms at evolved Yellowstone-type supervolcanoes

    Science.gov (United States)

    Wotzlaw, J.F.; Bindeman, I.N.; Watts, Kathryn E.; Schmitt, A.K.; Caricchi, L.; Schaltegger, U.

    2014-01-01

    The geological record contains evidence of volcanic eruptions that were as much as two orders of magnitude larger than the most voluminous eruption experienced by modern civilizations, the A.D. 1815 Tambora (Indonesia) eruption. Perhaps nowhere on Earth are deposits of such supereruptions more prominent than in the Snake River Plain–Yellowstone Plateau (SRP-YP) volcanic province (northwest United States). While magmatic activity at Yellowstone is still ongoing, the Heise volcanic field in eastern Idaho represents the youngest complete caldera cycle in the SRP-YP, and thus is particularly instructive for current and future volcanic activity at Yellowstone. The Heise caldera cycle culminated 4.5 Ma ago in the eruption of the ∼1800 km3 Kilgore Tuff. Accessory zircons in the Kilgore Tuff display significant intercrystalline and intracrystalline oxygen isotopic heterogeneity, and the vast majority are 18O depleted. This suggests that zircons crystallized from isotopically distinct magma batches that were generated by remelting of subcaldera silicic rocks previously altered by low-δ18O meteoric-hydrothermal fluids. Prior to eruption these magma batches were assembled and homogenized into a single voluminous reservoir. U-Pb geochronology of isotopically diverse zircons using chemical abrasion–isotope dilution–thermal ionization mass spectrometry yielded indistinguishable crystallization ages with a weighted mean 206Pb/238U date of 4.4876 ± 0.0023 Ma (MSWD = 1.5; n = 24). These zircon crystallization ages are also indistinguishable from the sanidine 40Ar/39Ar dates, and thus zircons crystallized close to eruption. This requires that shallow crustal melting, assembly of isolated batches into a supervolcanic magma reservoir, homogenization, and eruption occurred extremely rapidly, within the resolution of our geochronology (103–104 yr). The crystal-scale image of the reservoir configuration, with several isolated magma batches, is very similar to the

  7. New zircon (U-Th)/He and U/Pb eruption age for the Rockland tephra, western USA

    Science.gov (United States)

    Coble, Matthew A.; Burgess, Seth D.; Klemetti, Erik W.

    2017-09-01

    Eruption ages of a number of prominent Quaternary volcanic deposits remain inaccurately and/or imprecisely constrained, despite their importance as regional stratigraphic markers in paleo-environment reconstruction and as evidence of climate-altering eruptions. Accurately dating volcanic deposits presents challenging analytical considerations, including poor radiogenic yield, scarcity of datable minerals, and contamination of crystal populations by magma, eruption, and transport processes. One prominent example is the Rockland tephra, which erupted from the Lassen Volcanic Center in the southern Cascade arc. Despite a range in published eruption ages from 0.40 to 0.63 Ma, the Rockland tephra is extensively used as a marker bed across the western United States. To more accurately and precisely constrain the age of the Rockland tephra-producing eruption, we report U/Pb crystallization dates from the outermost ∼2 μm of zircon crystal faces (surfaces) using secondary ion mass spectrometry (SIMS). Our new weighted mean 238U/206Pb age for Rockland tephra zircon surfaces is 0.598 ± 0.013 Ma (2σ) and MSWD = 1.11 (mean square weighted deviation). As an independent test of the accuracy of this age, we obtained new (U-Th)/He dates from individual zircon grains from the Rockland tephra, which yielded a weighted mean age of 0.599 ± 0.012 Ma (2σ, MSWD = 5.13). We also obtained a (U-Th)/He age of 0.628 ± 0.014 Ma (MSWD = 1.19) for the Lava Creek Tuff member B, which was analyzed as a secondary standard to test the accuracy of the (U-Th)/He technique for Quaternary tephras, and to evaluate assumptions made in the model-age calculation. Concordance of new U/Pb and (U-Th)/He zircon ages reinforces the accuracy of our preferred Rockland tephra eruption age, and confirms that zircon surface dates sample zircon growth up to the time of eruption. We demonstrate the broad applicability of coupled U/Pb zircon-surface and single-grain zircon (U-Th)/He geochronology to accurate

  8. Seasonal variations of volcanic eruption frequencies

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    Do volcanic eruptions have a tendency to occur more frequently in the months of May and June? Some past evidence suggests that they do. The present study, based on the new eruption catalog of Simkin et al.(1981), investigates the monthly statistics of the largest eruptions, grouped according to explosive magnitude, geographical latitude, and year. At the 2-delta level, no month-to-month variations in eruption frequency are found to be statistically significant. Examination of previously published month-to-month variations suggests that they, too, are not statistically significant. It is concluded that volcanism, at least averaged over large portions of the globe, is probably not periodic on a seasonal or annual time scale.

  9. Deep Structure of the Zone of Tolbachik Fissure Eruptions (Kamchatka, Klyuchevskoy Volcano Group): Evidence from a Complex of Geological and Geophysical Data

    Science.gov (United States)

    Kugaenko, Yu. A.; Saltykov, V. A.; Gorvatikov, A. V.; Stepanova, M. Yu.

    2018-05-01

    With the use of the method of low-frequency microseismic sounding, the configuration of the magmatic feeding system of the Tolbachinsky Dol—a regional zone of areal basaltic volcanism in the southern part of the Klyuchevskoy volcano group in Kamchatka—is studied. The initial data are obtained by a stepby-step recording of the background microseismic noise in 2010-2015 within a thoroughly marked-out survey area covering the zones of fissure eruptions in 1975-1976 and 2012-2013 and, partly, the edifice of the Ploskii (flat) Tolbachik volcano. The depth sections reflecting the distributions of the relative velocities of seismic waves in the Earth's crust are constructed. For a more reliable interpretation of the revealed deep anomalies, the results of independent geological and geophysical studies are used. The ascertained low-velocity structures are closely correlated to the manifestations of present-day volcanism. It is shown that the feeding structure of the Tolbachinsky Dol is spatially heterogeneous, incorporating subvertical and lateral pipeshaped magma conduits, closely spaced magma feeding channels, and shallow magma reservoirs. A longlived local transcrustal magma conducting zone is revealed, and regularities in the deep structure of the feeding systems of fissure eruptions are identified. The configuration of the established subvertical magma conduits permits basalts moving to rise to the surface by different paths, which, inter alia, explains the contrasting magma compositions observed during a single eruption. Thus, based on the instrumental data, it is shown that the magmatic feeding structure of the Tolbachinsky Dol has a number of specific peculiarities and is significantly more complicated than has been previously thought about the areal volcanic fields.

  10. Observations of apparent superslow wave propagation in solar prominences

    Science.gov (United States)

    Raes, J. O.; Van Doorsselaere, T.; Baes, M.; Wright, A. N.

    2017-06-01

    Context. Phase mixing of standing continuum Alfvén waves and/or continuum slow waves in atmospheric magnetic structures such as coronal arcades can create the apparent effect of a wave propagating across the magnetic field. Aims: We observe a prominence with SDO/AIA on 2015 March 15 and find the presence of oscillatory motion. We aim to demonstrate that interpreting this motion as a magneto hydrodynamic (MHD) wave is faulty. We also connect the decrease of the apparent velocity over time with the phase mixing process, which depends on the curvature of the magnetic field lines. Methods: By measuring the displacement of the prominence at different heights to calculate the apparent velocity, we show that the propagation slows down over time, in accordance with the theoretical work of Kaneko et al. We also show that this propagation speed drops below what is to be expected for even slow MHD waves for those circumstances. We use a modified Kippenhahn-Schlüter prominence model to calculate the curvature of the magnetic field and fit our observations accordingly. Results: Measuring three of the apparent waves, we get apparent velocities of 14, 8, and 4 km s-1. Fitting a simple model for the magnetic field configuration, we obtain that the filament is located 103 Mm below the magnetic centre. We also obtain that the scale of the magnetic field strength in the vertical direction plays no role in the concept of apparent superslow waves and that the moment of excitation of the waves happened roughly one oscillation period before the end of the eruption that excited the oscillation. Conclusions: Some of the observed phase velocities are lower than expected for slow modes for the circumstances, showing that they rather fit with the concept of apparent superslow propagation. A fit with our magnetic field model allows for inferring the magnetic geometry of the prominence. The movie attached to Fig. 1 is available at http://www.aanda.org

  11. Apparent Solar Tornado-Like Prominences

    Science.gov (United States)

    Panasenco, Olga; Martin, Sara F.; Velli, Marco

    2014-02-01

    Recent high-resolution observations from the Solar Dynamics Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado-like prominences. This class of prominences was first introduced by Pettit ( Astrophys. J. 76, 9, 1932), who studied them over many years. Observations of tornado prominences similar to the ones seen by SDO had already been documented by Secchi ( Le Soleil, 1877). High-resolution and high-cadence multiwavelength data obtained by SDO reveal that the tornado-like appearance of these prominences is mainly an illusion due to projection effects. We discuss two different cases where prominences on the limb might appear to have a tornado-like behavior. One case of apparent vortical motions in prominence spines and barbs arises from the (mostly) 2D counterstreaming plasma motion along the prominence spine and barbs together with oscillations along individual threads. The other case of apparent rotational motion is observed in a prominence cavity and results from the 3D plasma motion along the writhed magnetic fields inside and along the prominence cavity as seen projected on the limb. Thus, the "tornado" impression results either from counterstreaming and oscillations or from the projection on the plane of the sky of plasma motion along magnetic-field lines, rather than from a true vortical motion around an (apparent) vertical or horizontal axis. We discuss the link between tornado-like prominences, filament barbs, and photospheric vortices at their base.

  12. Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD)

    Science.gov (United States)

    Génova, M.

    2012-04-01

    The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama) could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths) and 34 positive (representing maximum growths), the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600-1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

  13. SYMPATHETIC SOLAR FILAMENT ERUPTIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Rui; Liu, Ying D.; Zimovets, Ivan; Hu, Huidong; Yang, Zhongwei [State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190 (China); Dai, Xinghua, E-mail: liuxying@spaceweather.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2016-08-10

    The 2015 March 15 coronal mass ejection as one of the two that together drove the largest geomagnetic storm of solar cycle 24 so far was associated with sympathetic filament eruptions. We investigate the relations between the different filaments involved in the eruption. A surge-like small-scale filament motion is confirmed as the trigger that initiated the erupting filament with multi-wavelength observations and using a forced magnetic field extrapolation method. When the erupting filament moved to an open magnetic field region, it experienced an obvious acceleration process and was accompanied by a C-class flare and the rise of another larger filament that eventually failed to erupt. We measure the decay index of the background magnetic field, which presents a critical height of 118 Mm. Combining with a potential field source surface extrapolation method, we analyze the distributions of the large-scale magnetic field, which indicates that the open magnetic field region may provide a favorable condition for F2 rapid acceleration and have some relation with the largest solar storm. The comparison between the successful and failed filament eruptions suggests that the confining magnetic field plays an important role in the preconditions for an eruption.

  14. Kulanaokuaiki Tephra (ca, A.D. 400-1000): Newly recognized evidence for highly explosive eruptions at Kilauea Volcano, Hawai'i

    Science.gov (United States)

    Fiske, R.S.; Rose, T.R.; Swanson, D.A.; Champion, D.E.; McGeehin, J.P.

    2009-01-01

    K??lauea may be one of the world's most intensively monitored volcanoes, but its eruptive history over the past several thousand years remains rather poorly known. Our study has revealed the vestiges of thin basaltic tephra deposits, overlooked by previous workers, that originally blanketed wide, near-summit areas and extended more than 17 km to the south coast of Hawai'i. These deposits, correlative with parts of tephra units at the summit and at sites farther north and northwest, show that K??lauea, commonly regarded as a gentle volcano, was the site of energetic pyroclastic eruptions and indicate the volcano is significantly more hazardous than previously realized. Seventeen new calibrated accelerator mass spectrometry (AMS) radiocarbon ages suggest these deposits, here named the Kulanaokuaiki Tephra, were emplaced ca. A.D. 400-1000, a time of no previously known pyroclastic activity at the volcano. Tephra correlations are based chiefly on a marker unit that contains unusually high values of TiO2 and K2O and on paleomagnetic signatures of associated lava flows, which show that the Kulanaokuaiki deposits are the time-stratigraphic equivalent of the upper part of a newly exhumed section of the Uw??kahuna Ash in the volcano's northwest caldera wall. This section, thought to have been permanently buried by rockfalls in 1983, is thicker and more complete than the previously accepted type Uw??kahuna at the base of the caldera wall. Collectively, these findings justify the elevation of the Uw??kahuna Ash to formation status; the newly recognized Kulanaokuaiki Tephra to the south, the chief focus of this study, is defined as a member of the Uw??kahuna Ash. The Kulanaokuaiki Tephra is the product of energetic pyroclastic falls; no surge- or pyroclastic-flow deposits were identified with certainty, despite recent interpretations that Uw??kahuna surges extended 10-20 km from K??lauea's summit. ?? 2009 Geological Society of America.

  15. Extreme pointer years in tree-ring records of Central Spain as evidence of climatic events and the eruption of the Huaynaputina Volcano (Peru, 1600 AD

    Directory of Open Access Journals (Sweden)

    M. Génova

    2012-04-01

    Full Text Available The study of pointer years of numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama could provide complementary information about climate variability over the last 405 yr. In total, 64 pointer years have been identified: 30 negative (representing minimum growths and 34 positive (representing maximum growths, the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation was found to be the most limiting factor for the growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, these pointer years and intervals are not evenly distributed throughout time. Both in the first half of the 17th and in the second half of 20th, they were more frequent and more extreme and these periods are the most notable for the frequency of negative pointer years in Central Spain. The interval 1600–1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. We infer that this special minimum annual increase was the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of Southern Europe have been demonstrated.

  16. Extreme pointer years in tree-ring records of Central Spain as evidence of volcanic eruptions (Huaynaputina, Peru, 1600 AC) and other climatic events

    Science.gov (United States)

    Génova, M.

    2011-12-01

    The study of pointer years based on the numerous tree-ring chronologies of the central Iberian Peninsula (Sierra de Guadarrama) could provide complementary information about climate variability over the last 405 years. In total, 64 pointer years have been identified: 30 negative (representing minimum growths) and 34 positive (representing maximum growths), the most significant of these being 1601, 1963 and 1996 for the negative ones, and 1734 and 1737 for the positive ones. Given that summer precipitation has been the most incident factor in the general variability of growth of Pinus in the Sierra de Guadarrama in the second half of the 20th century, it is also an explanatory factor in almost 50% of the extreme growths. Furthermore, the data show that there has been variability over the centuries in the distribution of the frequencies of pointer years and intervals. The first half of the 17th century, together with the second half of the 20th century, constitute the two most notable periods for the frequency of negative pointer years in Central Spain. This variability was sufficiently notable to affirm that, both in the 17th and 20th centuries, the macroclimatic anomalies that affected growth were more frequent and more extreme than in the other two centuries analysed. The period 1600-1602 is of special significance, being one of the most unfavourable for tree growth in the centre of Spain, with 1601 representing the minimum index in the regional chronology. It is possible to infer that these phenomena are the effect of the eruption of Huaynaputina, which occurred in Peru at the beginning of 1600 AD. This is the first time that the effects of this eruption in the tree-ring records of central and southern Europe have been demonstrated.

  17. Micro-textures in plagioclase from 1994–1995 eruption, Barren Island Volcano: Evidence of dynamic magma plumbing system in the Andaman subduction zone

    Directory of Open Access Journals (Sweden)

    M.L. Renjith

    2014-01-01

    Full Text Available A systematic account of micro-textures and a few compositional profiles of plagioclase from high-alumina basaltic aa lava erupted during the year 1994–1995, from Barren Island Volcano, NE India ocean, are presented for the first time. The identified micro-textures can be grouped into two categories: (i Growth related textures in the form of coarse/fine-sieve morphology, fine-scale oscillatory zoning and resorption surfaces resulted when the equilibrium at the crystal-melt interface was fluctuated due to change in temperature or H2O or pressure or composition of the crystallizing melt; and (ii morphological texture, like glomerocryst, synneusis, swallow-tailed crystal, microlite and broken crystals, formed by the influence of dynamic behavior of the crystallizing magma (convection, turbulence, degassing, etc.. Each micro-texture has developed in a specific magmatic environment, accordingly, a first order magma plumbing model and crystallization dynamics are envisaged for the studied lava unit. Magma generated has undergone extensive fractional crystallization of An-rich plagioclase in stable magmatic environment at a deeper depth. Subsequently they ascend to a shallow chamber where the newly brought crystals and pre-existing crystals have undergone dynamic crystallization via dissolution-regrowth processes in a convective self-mixing environment. Such repeated recharge-recycling processes have produced various populations of plagioclase with different micro-textural stratigraphy in the studied lava unit. Intermittent degassing and eruption related decompression have also played a major role in the final stage of crystallization dynamics.

  18. MHD Simulations of the Eruption of Coronal Flux Ropes under Coronal Streamers

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Yuhong, E-mail: yfan@ucar.edu [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green Drive, Boulder, CO 80301 (United States)

    2017-07-20

    Using three-dimensional magnetohydrodynamic (MHD) simulations, we investigate the eruption of coronal flux ropes underlying coronal streamers and the development of a prominence eruption. We initialize a quasi-steady solution of a coronal helmet streamer, into which we impose at the lower boundary the slow emergence of a part of a twisted magnetic torus. As a result, a quasi-equilibrium flux rope is built up under the streamer. With varying streamer sizes and different lengths and total twists of the flux rope that emerges, we found different scenarios for the evolution from quasi-equilibrium to eruption. In the cases with a broad streamer, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with increasing height until it eventually develops a “hernia-like” ejective eruption. For significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to runaway radiative cooling. Once formed, the prominence-carrying field becomes significantly non-force-free due to the weight of the prominence, despite having low plasma β . As the flux rope erupts, the prominence erupts, showing substantial draining along the legs of the erupting flux rope. The prominence may not show a kinked morphology even though the flux rope becomes kinked. On the other hand, in the case with a narrow streamer, the flux rope with less than one wind of twist can erupt via the onset of the torus instability.

  19. TANGLED MAGNETIC FIELDS IN SOLAR PROMINENCES

    International Nuclear Information System (INIS)

    Van Ballegooijen, A. A.; Cranmer, S. R.

    2010-01-01

    Solar prominences are an important tool for studying the structure and evolution of the coronal magnetic field. Here we consider so-called hedgerow prominences, which consist of thin vertical threads. We explore the possibility that such prominences are supported by tangled magnetic fields. A variety of different approaches are used. First, the dynamics of plasma within a tangled field is considered. We find that the contorted shape of the flux tubes significantly reduces the flow velocity compared to the supersonic free fall that would occur in a straight vertical tube. Second, linear force-free models of tangled fields are developed, and the elastic response of such fields to gravitational forces is considered. We demonstrate that the prominence plasma can be supported by the magnetic pressure of a tangled field that pervades not only the observed dense threads but also their local surroundings. Tangled fields with field strengths of about 10 G are able to support prominence threads with observed hydrogen density of the order of 10 11 cm -3 . Finally, we suggest that the observed vertical threads are the result of Rayleigh-Taylor instability. Simulations of the density distribution within a prominence thread indicate that the peak density is much larger than the average density. We conclude that tangled fields provide a viable mechanism for magnetic support of hedgerow prominences.

  20. Magnetohydrodynamic (MHD) simulation of solar prominence formation

    International Nuclear Information System (INIS)

    Bao, J.

    1987-01-01

    Formation of Kippenhahn-Schluter type solar prominences by chromospheric mass injection is studied via numerical simulation. The numerical model is based on a two-dimensional, time-dependent magnetohydrodynamic (MHD) theory. In addition, an analysis of gravitational thermal MHD instabilities related to condensation is performed by using the small-perturbation method. The conclusions are: (1) Both quiescent and active-region prominences can be formed by chromospheric mass injection, provided certain optimum conditions are satisfied. (2) Quiescent prominences cannot be formed without condensation, though enough mass is supplied from chromosphere. The mass of a quiescent prominence is composed of both the mass injected from the chromosphere and the mass condensed from the corona. On the other hand, condensation is not important to active region prominence formation. (3) In addition to channeling and supporting effects, the magnetic field plays another important role, i.e. containing the prominence material. (4) In the model cases, prominences are supported by the Lorentz force, the gas-pressure gradient and the mass-injection momentum. (5) Due to gravity, more MHD condensation instability modes appear in addition to the basic condensation mode

  1. Geodetic evidence for en echelon dike emplacement and concurrent slow slip during the June 2007 intrusion and eruption at Kīlauea volcano, Hawaii

    Science.gov (United States)

    Montgomery-Brown, E. K.; Sinnett, D.K.; Poland, M.; Segall, P.; Orr, T.; Zebker, H.; Miklius, Asta

    2010-01-01

    A series of complex events at Kīlauea Volcano, Hawaii, 17 June to 19 June 2007, began with an intrusion in the upper east rift zone (ERZ) and culminated with a small eruption (1500 m3). Surface deformation due to the intrusion was recorded in unprecedented detail by Global Positioning System (GPS) and tilt networks as well as interferometric synthetic aperture radar (InSAR) data acquired by the ENVISAT and ALOS satellites. A joint nonlinear inversion of GPS, tilt, and InSAR data yields a deflationary source beneath the summit caldera and an ENE-striking uniform-opening dislocation with ~2 m opening, a dip of ∼80° to the south, and extending from the surface to ~2 km depth. This simple model reasonably fits the overall pattern of deformation but significantly misfits data near the western end of an inferred dike-like source. Three more complex dike models are tested that allow for distributed opening including (1) a dike that follows the surface trace of the active rift zone, (2) a dike that follows the symmetry axis of InSAR deformation, and (3) two en echelon dike segments beneath mapped surface cracks and newly formed steaming areas. The en echelon dike model best fits near-field GPS and tilt data. Maximum opening of 2.4 m occurred on the eastern segment beneath the eruptive vent. Although this model represents the best fit to the ERZ data, it still fails to explain data from a coastal tiltmeter and GPS sites on Kīlauea's southwestern flank. The southwest flank GPS sites and the coastal tiltmeter exhibit deformation consistent with observations of previous slow slip events beneath Kīlauea's south flank, but inconsistent with observations of previous intrusions. Slow slip events at Kīlauea and elsewhere are thought to occur in a transition zone between locked and stably sliding zones of a fault. An inversion including slip on a basal decollement improves fit to these data and suggests a maximum of ~15 cm of seaward fault motion, comparable to previous slow

  2. Topic prominence in Chinese EFL learners’ interlanguage

    Directory of Open Access Journals (Sweden)

    Shaopeng Li

    2014-01-01

    Full Text Available The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004. The research target are the topic chain, which is the main topic-prominent structure in Chinese discourse, and zero anaphora, which is the most common topic anaphora in the topic chain. Two important findings emerged from the present study. First, the characteristics of Chinese topic chains are transferrable to the interlanguage of Chinese EFL learners, thus resulting in overgeneralization of the zero anaphora. Second, the interlanguage discourse of Chinese EFL learners reflects a change of the second language acquisition process from topic-prominence to subject-prominence, thus lending support to the discourse transfer hypothesis.

  3. EUV observations of quiescent prominences from Skylab

    International Nuclear Information System (INIS)

    Moe, O.K.

    1979-01-01

    The authors report measurements of line intensities and line widths for three quiescent prominences observed with the Naval Research Laboratory slit spectrograph on ATM/Skylab. The wavelengths of the observed lines cover the range 1175 A to 1960 A. The measured intensities have been calibrated to within approximately a factor 2 and are average intensities over a 2 arc sec by 60 arc set slit. Nonthermal velocities are derived from the measured line widths. The nonthermal velocity is found to increase with temperature in the prominence transition zone. Electron densities and pressures are derived from density sensitive line ratios. Electron pressures for two of the prominences are found to lie in the range 0.04-0.08 dyn cm -2 , while values for the third and most intense and active of the three prominences are in the range 0.07-0.22 dyn cm -2 . (Auth.)

  4. PLASMOID EJECTIONS AND LOOP CONTRACTIONS IN AN ERUPTIVE M7.7 SOLAR FLARE: EVIDENCE OF PARTICLE ACCELERATION AND HEATING IN MAGNETIC RECONNECTION OUTFLOWS

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wei [Lockheed Martin Solar and Astrophysics Laboratory, Building 252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Chen Qingrong; Petrosian, Vahe [Department of Physics, Stanford University, Stanford, CA 94305 (United States)

    2013-04-20

    Where particle acceleration and plasma heating take place in relation to magnetic reconnection is a fundamental question for solar flares. We report analysis of an M7.7 flare on 2012 July 19 observed by SDO/AIA and RHESSI. Bi-directional outflows in forms of plasmoid ejections and contracting cusp-shaped loops originate between an erupting flux rope and underlying flare loops at speeds of typically 200-300 km s{sup -1} up to 1050 km s{sup -1}. These outflows are associated with spatially separated double coronal X-ray sources with centroid separation decreasing with energy. The highest temperature is located near the nonthermal X-ray loop-top source well below the original heights of contracting cusps near the inferred reconnection site. These observations suggest that the primary loci of particle acceleration and plasma heating are in the reconnection outflow regions, rather than the reconnection site itself. In addition, there is an initial ascent of the X-ray and EUV loop-top source prior to its recently recognized descent, which we ascribe to the interplay among multiple processes including the upward development of reconnection and the downward contractions of reconnected loops. The impulsive phase onset is delayed by 10 minutes from the start of the descent, but coincides with the rapid speed increases of the upward plasmoids, the individual loop shrinkages, and the overall loop-top descent, suggestive of an intimate relation of the energy release rate and reconnection outflow speed.

  5. Volcanic eruptions on Io

    Science.gov (United States)

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

    1981-01-01

    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.

  6. Energy release from a stream of infalling prominence debris on 2011 September 7-8

    Science.gov (United States)

    Inglis, A. R.; Gilbert, H. R.; Ofman, L.

    2017-12-01

    In recent years high-resolution and high-cadence EUV imaging has revealed a new phenomenon, impacting prominence debris, where prominence material from failed or partial eruptions can impact the lower atmosphere and release energy. We present a clear example of this phenomenon occurring on 2011 September 7-8. The initial eruption of prominence material was associated with an X1.8-class flare from AR11283, occurring at 22:30 UT on 2011 September 7, resulting in a semi-continuous stream of this material returning to the solar surface between 00:20 - 00:40 UT on 2011 September 8. A substantial area remote from the original active region experienced brightening in multiple EUV channels observed by SDO/AIA. Using the differential emission measure, we estimated the energetic properties of this event. We found that the radiated energy of the impacted plasma was of order 10^27 ergs, while the upper limit on the thermal energy peaked at 10^28 ergs. Based on these estimates we were able to determine the mass content of the debris to be in the range 2x10^14 energy release takes place during these events, and that such impacts may be used as a novel diagnostic tool for investigating prominence material properties.

  7. An Investigation of the Physical Properties of Erupting Solar Prominences, Phase II

    Science.gov (United States)

    2014-12-30

    recently). In addition to the focus difference between channels there is also an overall retraction of the O2 focus westward, and concurrent movement of...clear images. The entire process takes ≈13:50 minutes. In that time the telescope moves ≈4˚ in RA, and the image rotator moves 2˚. Declination movement ...The 1st line is a Si I solar line at 1082.7 nm. The 2nd line is a telluric line formed by water vapor in earth’s atmosphere at 1083.2 nm. This

  8. A twisted flux-tube model for solar prominences. I. General properties

    International Nuclear Information System (INIS)

    Priest, E.R.; Hood, A.W.; Anzer, U.

    1989-01-01

    It is proposed that a solar prominence consists of cool plasma supported in a large-scale curved and twisted magnetic flux tube. As long as the flux tube is untwisted, its curvature is concave toward the solar surface, and so it cannot support dense plasma against gravity. However, when it is twisted sufficiently, individual field lines may acquire a convex curvature near their summits and so provide support. Cool plasma then naturally tends to accumulate in such field line dips either by injection from below or by thermal condensation. As the tube is twisted up further or reconnection takes place below the prominence, one finds a transition from normal to inverse polarity. When the flux tube becomes too long or is twisted too much, it loses stability and its true magnetic geometry as an erupting prominence is revealed more clearly. 56 refs

  9. SOLAR LIMB PROMINENCE CATCHER AND TRACKER (SLIPCAT): AN AUTOMATED SYSTEM AND ITS PRELIMINARY STATISTICAL RESULTS

    International Nuclear Information System (INIS)

    Wang Yuming; Cao Hao; Chen Junhong; Zhang Tengfei; Yu Sijie; Zheng Huinan; Shen Chenglong; Wang, S.; Zhang Jie

    2010-01-01

    In this paper, we present an automated system, which has the capability to catch and track solar limb prominences based on observations from the extreme-ultraviolet (EUV) 304 A passband. The characteristic parameters and their evolution, including height, position angle, area, length, and brightness, are obtained without manual interventions. By applying the system to the STEREO-B/SECCHI/EUVI 304 A data during 2007 April-2009 October, we obtain a total of 9477 well-tracked prominences and a catalog of these events available online. A detailed analysis of these prominences suggests that the system has a rather good performance. We have obtained several interesting statistical results based on the catalog. Most prominences appear below the latitude of 60 0 and at the height of about 26 Mm above the solar surface. Most of them are quite stable during the period they are tracked. Nevertheless, some prominences have an upward speed of more than 100 km s -1 , and some others show significant downward and/or azimuthal speeds. There are strong correlations among the brightness, area, and height. The expansion of a prominence is probably one major cause of its fading during the rising or erupting process.

  10. DYNAMICS OF A PROMINENCE-HORN STRUCTURE DURING ITS EVAPORATION IN THE SOLAR CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bing; Chen, Yao; Fu, Jie; Li, Bo [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, and Institute of Space Sciences, Shandong University, Weihai 264209 (China); Li, Xing [Department of Physics, Aberystwyth University, Aberystwyth, Ceredigion, SY23 3BZ (United Kingdom); Liu, Wei, E-mail: yaochen@sdu.edu.cn [Stanford-Lockheed Institute for Space Research, Stanford University, Stanford, CA 94305 (United States)

    2016-08-20

    The physical connections among and formation mechanisms of various components of the prominence-horn cavity system remain elusive. Here we present observations of such a system, focusing on a section of the prominence that rises and separates gradually from the main body. This forms a configuration sufficiently simple to yield clues regarding the above issues. It is characterized by embedding horns, oscillations, and a gradual disappearance of the separated material. The prominence-horn structure exhibits a large-amplitude longitudinal oscillation with a period of ∼150 minutes and an amplitude of ∼30 Mm along the trajectory defined by the concave horn structure. The horns also experience a simultaneous transverse oscillation with a much smaller amplitude (∼3 Mm) and a shorter period (∼10–15 minutes), likely representative of a global mode of the large-scale magnetic structure. The gradual disappearance of the structure indicates that the horn, an observational manifestation of the field-aligned transition region separating the cool and dense prominence from the hot and tenuous corona, is formed due to the heating and diluting process of the central prominence mass; most previous studies suggested that it is the opposite process, i.e., the cooling and condensation of coronal plasmas, that formed the horn. This study also demonstrates how the prominence transports magnetic flux to the upper corona, a process essential for the gradual build-up of pre-eruption magnetic energy.

  11. Premature eruption of the premolars.

    Science.gov (United States)

    Camm, J H; Schuler, J L

    1990-01-01

    This paper presents a variety of cases in which very early loss of abscessed primary molars caused early eruption of the permanent successors. Clinical sequelae including ectopic eruption, alteration of eruption sequence, arch-length inadequacy and tooth impaction are illustrated by five case reports.

  12. Setting of the Father's Day Eruption at Kilauea

    Science.gov (United States)

    Swanson, D. A.

    2007-12-01

    the zone. The Koa`e fault system joins the east rift zone at the curve. The complex structural setting likely affects the frequency of magmatic activity in the segment. All of the eruptive and intrusive activity results in storage of isolated magma bodies. Not surprisingly, petrologists find evidence that summit magma mixes with stored, fractionated magma. The area near Makaopuhi Crater and Kane Nui o Hamo is a particular focus, inferred since the mid-1960s to harbor a shallow magma reservoir. All of the eruptions and intrusions are accompanied by sharp deflation and shallow seismicity at the summit and shallow seismicity and uplift along the intrusion or eruptive fissures. Most often, no seismicity occurs between the summit and the area of intrusion or eruption. Within that area, seismicity commonly migrates downrift but occasionally uprift. Similarly, crack opening generally progresses downrift, with a few exceptions. Cracks generally trend about 65 degrees and can be either left- or right-stepping. Cracks open along azimuths of 155-175, with local exceptions. There is no structural difference between eruptive cracks (fissures) and non- eruptive cracks. Single eruptive fissures rarely exceed 200 m in length, instead stepping within en echelon zones above a presumably linear dike. Since the late 1960s, widening has been measured across the active area during eruptions and intrusions, first by EDM and then by satellite-based systems. The opening is nearly symmetrical within the rift zone, but farther out the north flank barely responds whereas the south flank moves seaward. Available leveling data show uplift on either side of the dike and subsidence along the crest. Examples of deformation in the 1960s and 1970s will be presented, and bibliographic references to past activity will be available.

  13. Eruption of Pele

    Science.gov (United States)

    1995-01-01

    The eruption of Pele on Jupiter's moon Io. The volcanic plume rises 300 kilometers above the surface in an umbrella-like shape. The plume fallout covers an area the size of Alaska. The vent is a dark spot just north of the triangular-shaped plateau (right center). To the left, the surface is covered by colorful lava flows rich in sulfur.

  14. Complicated lichenoid drug eruption.

    Science.gov (United States)

    Armour, Katherine; Lowe, Patricia

    2005-02-01

    We report a case of severe lichenoid drug eruption with multiple possible causative agents. A hepatitis C-positive male presented with a short history of painful erosions of the vermilion, lichenoid lesions on the buccal mucosa and glans penis, and erosions and lichenification of the scrotum. In addition, he had a pruritic polymorphic eruption over the scalp, trunk and limbs, comprising psoriasiform and eczematous lesions. He had received combination therapy of pegylated interferon-alpha-2a and ribavirin, along with granulocyte colony-stimulating factor for interferon-induced leucopenia, and propranolol for portal hypertension. The former three agents were ceased 3 weeks prior to presentation, but he remained on propranolol at the initial dermatology consultation. The polymorphous clinical picture was consistent with lichenoid drug eruption, which was confirmed on histology. The papulosquamous eruption responded quickly to 2 weeks of oral prednisone 25 mg daily, which was tapered to 1 mg over 3 months and then ceased. The mucosal lesions were slow to improve and required the addition of tacrolimus 0.03% solution t.d.s. for complete resolution.

  15. Volcanic Eruptions and Climate

    Science.gov (United States)

    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.

  16. Automated image based prominent nucleoli detection.

    Science.gov (United States)

    Yap, Choon K; Kalaw, Emarene M; Singh, Malay; Chong, Kian T; Giron, Danilo M; Huang, Chao-Hui; Cheng, Li; Law, Yan N; Lee, Hwee Kuan

    2015-01-01

    Nucleolar changes in cancer cells are one of the cytologic features important to the tumor pathologist in cancer assessments of tissue biopsies. However, inter-observer variability and the manual approach to this work hamper the accuracy of the assessment by pathologists. In this paper, we propose a computational method for prominent nucleoli pattern detection. Thirty-five hematoxylin and eosin stained images were acquired from prostate cancer, breast cancer, renal clear cell cancer and renal papillary cell cancer tissues. Prostate cancer images were used for the development of a computer-based automated prominent nucleoli pattern detector built on a cascade farm. An ensemble of approximately 1000 cascades was constructed by permuting different combinations of classifiers such as support vector machines, eXclusive component analysis, boosting, and logistic regression. The output of cascades was then combined using the RankBoost algorithm. The output of our prominent nucleoli pattern detector is a ranked set of detected image patches of patterns of prominent nucleoli. The mean number of detected prominent nucleoli patterns in the top 100 ranked detected objects was 58 in the prostate cancer dataset, 68 in the breast cancer dataset, 86 in the renal clear cell cancer dataset, and 76 in the renal papillary cell cancer dataset. The proposed cascade farm performs twice as good as the use of a single cascade proposed in the seminal paper by Viola and Jones. For comparison, a naive algorithm that randomly chooses a pixel as a nucleoli pattern would detect five correct patterns in the first 100 ranked objects. Detection of sparse nucleoli patterns in a large background of highly variable tissue patterns is a difficult challenge our method has overcome. This study developed an accurate prominent nucleoli pattern detector with the potential to be used in the clinical settings.

  17. Automated image based prominent nucleoli detection

    Directory of Open Access Journals (Sweden)

    Choon K Yap

    2015-01-01

    Full Text Available Introduction: Nucleolar changes in cancer cells are one of the cytologic features important to the tumor pathologist in cancer assessments of tissue biopsies. However, inter-observer variability and the manual approach to this work hamper the accuracy of the assessment by pathologists. In this paper, we propose a computational method for prominent nucleoli pattern detection. Materials and Methods: Thirty-five hematoxylin and eosin stained images were acquired from prostate cancer, breast cancer, renal clear cell cancer and renal papillary cell cancer tissues. Prostate cancer images were used for the development of a computer-based automated prominent nucleoli pattern detector built on a cascade farm. An ensemble of approximately 1000 cascades was constructed by permuting different combinations of classifiers such as support vector machines, eXclusive component analysis, boosting, and logistic regression. The output of cascades was then combined using the RankBoost algorithm. The output of our prominent nucleoli pattern detector is a ranked set of detected image patches of patterns of prominent nucleoli. Results: The mean number of detected prominent nucleoli patterns in the top 100 ranked detected objects was 58 in the prostate cancer dataset, 68 in the breast cancer dataset, 86 in the renal clear cell cancer dataset, and 76 in the renal papillary cell cancer dataset. The proposed cascade farm performs twice as good as the use of a single cascade proposed in the seminal paper by Viola and Jones. For comparison, a naive algorithm that randomly chooses a pixel as a nucleoli pattern would detect five correct patterns in the first 100 ranked objects. Conclusions: Detection of sparse nucleoli patterns in a large background of highly variable tissue patterns is a difficult challenge our method has overcome. This study developed an accurate prominent nucleoli pattern detector with the potential to be used in the clinical settings.

  18. Topic Prominence in Chinese EFL Learners' Interlanguage

    Science.gov (United States)

    Li, Shaopeng; Yang, Lianrui

    2014-01-01

    The present study aims to investigate the general characteristics of topicprominent typological interlanguage development of Chinese learners of English in terms of acquiring subject-prominent English structures from a discourse perspective. Topic structures mainly appear in Chinese discourse in the form of topic chains (Wang, 2002; 2004). The…

  19. Explosive volcanism on Mercury: Analysis of vent and deposit morphology and modes of eruption

    Science.gov (United States)

    Jozwiak, Lauren M.; Head, James W.; Wilson, Lionel

    2018-03-01

    The MESSENGER mission revealed, for the first time, conclusive evidence of explosive volcanism on Mercury. Several previous works have cataloged the appearance and location of explosive volcanism on the planet using a variety of identifying characteristics, including vent presence and deposit color as seen in multispectral image mosaics. We present here a comprehensive catalog of vents of likely volcanic origin; our classification scheme emphasizes vent morphology. We have analyzed the morphologies of all vents in our catalog, and recognize three main morphologies: "simple vent", "pit vent", and "vent-with-mound". The majority of vents we identify are located within impact craters. The spatial distribution of vents does not correlate with the locations of volcanic smooth plains deposits, in contrast to the Moon, nor do vents correlate with the locations of large impact basins (except for the Caloris and Tolstoj basins). Using the degradation state of the vent host crater as a proxy for maximum age, we suggest that vent formation has been active through the Mansurian and into the Kuiperian periods, although the majority of vents were likely formed much earlier in mercurian history. The morphologies and locations of vents are used to investigate a set of plausible formation geometries. We find that the most likely and most prevalent formation geometry is that of a dike, stalled at depth, which then explosively vents to the surface. We compare the vent and deposit size of mercurian pyroclastic deposits with localized and regional lunar pyroclastic deposits, and find a range of possible eruption energies and corresponding variations in eruption style. Localized lunar pyroclastic deposits and the majority of mercurian pyroclastic deposits show evidence for eruption that is consistent with the magmatic foam at the top of a dike reaching a critical gas volume fraction. A subset of mercurian vents, including the prominent Copland-Rachmaninoff vent to the northeast of the

  20. Large erupted complex odontoma

    Directory of Open Access Journals (Sweden)

    Vijeev Vasudevan

    2009-01-01

    Full Text Available Odontomas are a heterogeneous group of jaw bone lesions, classified as odontogenic tumors which usually include well-diversified dental tissues. Odontoma is a term introduced to the literature by Broca in 1867. Trauma, infection and hereditary factors are the possible causes of forming this kind of lesions. Among odontogenic tumors, they constitute about 2/3 of cases. These lesions usually develop slowly and asymptomatically, and in most cases they do not cross the bone borders. Two types of odontoma are recognized: compound and complex. Complex odontomas are less common than the compound variety in the ratio 1:2.3. Eruption of an odontoma in the oral cavity is rare. We present a case of complex odontoma, in which apparent eruption has occurred in the area of the right maxillary second molar region.

  1. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents.

    Science.gov (United States)

    Batista, Klaus Bsl; Thiruvenkatachari, Badri; Harrison, Jayne E; O'Brien, Kevin D

    2018-03-13

    Prominent upper front teeth are a common problem affecting about a quarter of 12-year-old children in the UK. The condition develops when permanent teeth erupt. These teeth are more likely to be injured and their appearance can cause significant distress. Children are often referred to an orthodontist for treatment with dental braces to reduce the prominence of their teeth. If a child is referred at a young age, the orthodontist is faced with the dilemma of whether to treat the patient early or to wait and provide treatment in adolescence. To assess the effects of orthodontic treatment for prominent upper front teeth initiated when children are seven to 11 years old ('early treatment' in two phases) compared to in adolescence at around 12 to 16 years old ('late treatment' in one phase); to assess the effects of late treatment compared to no treatment; and to assess the effects of different types of orthodontic braces. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 27 September 2017), the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 8), MEDLINE Ovid (1946 to 27 September 2017), and Embase Ovid (1980 to 27 September 2017). The US National Institutes of Health Ongoing Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Randomised controlled trials of orthodontic treatments to correct prominent upper front teeth (Class II malocclusion) in children and adolescents. We included trials that compared early treatment in children (two-phase) with any type of orthodontic braces (removable, fixed, functional) or head-braces versus late treatment in adolescents (one-phase) with any type of orthodontic braces or head-braces, and trials that compared any

  2. Aesthetic Refinements in Patients with Prominent Eyes.

    Science.gov (United States)

    Richter, Dirk F; Schwaiger, Nina; Wiedner, Maria

    2015-12-01

    The treatment of prominent eyes is still a challenging task. As well as the surgery, proper preoperative diagnosis differentiating between patients with and without Graves ophthalmopathy plays an important role. In functionally asymptomatic patients with Graves disease suffering from the aesthetic impairment of prominent eyes, the transpalpebral decompression by intraorbital fat removal technique has been proved to be reliable, effective, safe, and easily performed by a trained and experienced oculoplastic surgeon. This technique provides long-lasting results, leading to improvement not only in visual function but also in personal well-being and in the patient's social life, with a high benefit-to-risk ratio. The most powerful tool to treat the lower lid deformity and malar bags in patients without Graves disease is the subperiosteal midface lift. It shortens the lid-cheek junction and blends the retaining periorbital ligaments. Furthermore, it adds volume to the lower lid and gives a stable support. By the nature of the procedure, it also turns a negative into a positive vector. In experienced hands, Olivari's orbital decompression and Hester's midface lift are ideal options for the treatment of prominent eyes. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  3. Evaluation of Kilauea Eruptions By Using Stable Isotope Analysis

    Science.gov (United States)

    Rahimi, K. E.; Bursik, M. I.

    2016-12-01

    Kilauea, on the island of Hawaii, is a large volcanic edifice with numerous named vents scattered across its surface. Halema`uma`u crater sits with Kilauea caldera, above the magma reservoir, which is the main source of lava feeding most vents on Kilauea volcano. Halema`uma`u crater produces basaltic explosive activity ranging from weak emission to sub-Plinian. Changes in the eruption style are thought to be due to the interplay between external water and magma (phreatomagmatic/ phreatic), or to segregation of gas from magma (magmatic) at shallow depths. Since there are three different eruption mechanisms (phreatomagmatic, phreatic, and magmatic), each eruption has its own isotope ratios. The aim of this study is to evaluate the eruption mechanism by using stable isotope analysis. Studying isotope ratios of D/H and δ18O within fluid inclusion and volcanic glass will provide an evidence of what driven the eruption. The results would be determined the source of water that drove an eruption by correlating the values with water sources (groundwater, rainwater, and magmatic water) since each water source has a diagnostic value of D/H and δ18O. These results will provide the roles of volatiles in eruptions. The broader application of this research is that these methods could help volcanologists forecasting and predicting the current volcanic activity by mentoring change in volatiles concentration within deposits.

  4. Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or causality?

    Directory of Open Access Journals (Sweden)

    R. Funiciello

    2008-06-01

    Full Text Available Anecdotes of concurrent eruptions at Etna, Stromboli, and Vulcano (Southern Italy have persisted for more than 2000 years and volcanologists in recent and past times have hypothesized a causal link among these volcanoes. Here this hypothesis is tested. To introduce the problem and provide examples of the type of expected volcanic phenomena, narratives of the most notable examples of concurrent eruptions are provided. Then the frequency of eruptions at each individual volcano is analysed for about the last 300 years and the expected probability of concurrent eruptions is calculated to compare it to the observed probability. Results show that the occurrence of concurrent eruptions is often more frequent than a random probability, particularly for the Stromboli-Vulcano pair. These results are integrated with a statistical analysis of the earthquake catalogue to find evidence of linked seismicity in the Etnean and Aeolian areas. Results suggest a moderate incidence of non-random concurrent eruptions, but available data are temporally limited and do not allow an unequivocal identification of plausible triggers; our results, however, are the first attempt to quantify a more-than-2000-years-old curious observation and constitute a starting point for more sophisticated analyses of new data in the future. We look forward to our prediction of a moderate incidence of concurrent eruptions being confirmed or refuted with the passage of time and occurrence of new events.

  5. LARGE-SCALE FLOWS IN PROMINENCE CAVITIES

    International Nuclear Information System (INIS)

    Schmit, D. J.; Gibson, S. E.; Tomczyk, S.; Reeves, K. K.; Sterling, Alphonse C.; Brooks, D. H.; Williams, D. R.; Tripathi, D.

    2009-01-01

    Regions of rarefied density often form cavities above quiescent prominences. We observed two different cavities with the Coronal Multichannel Polarimeter on 2005 April 21 and with Hinode/EIS on 2008 November 8. Inside both of these cavities, we find coherent velocity structures based on spectral Doppler shifts. These flows have speeds of 5-10 km s -1 , occur over length scales of tens of megameters, and persist for at least 1 hr. Flows in cavities are an example of the nonstatic nature of quiescent structures in the solar atmosphere.

  6. Hydrogen line formation in the quescent prominences

    International Nuclear Information System (INIS)

    Tsovookhuu, Ch.

    1980-01-01

    Equations of transfer and statistical equilibrium for hydronen atom with eight bound levels and continuum are solved simultaneously. A plane-parallel layer located perpendicular to the Sun surface is taken as a geometrical model. Input parameters of the physical model are optical thickness in the center of Hsub(α) line, electron temperature and concentration in the layer center are well as temperature and density gradients. Functions of sources, line profiles, total energies and the Balmer decrements, which are compared with observations and theoretical calculations made by other authors, have been calculated. The comparison shows that the results are quite acceptable and can be used when analyzing the spectrum and determining physical parameters of solar prominences. Dependence of different performances of the line (equivalent width, central intensity, halfwidth, depth of central depression etc.) on values of initial model parameters is investigated. Line halfwidth is more sensitive to the temperatuu value in the layer center, while central intensity - to the value of temperature gradient and a depth of central depression - to electron concentration. Calculated were shares of primary sources responsible for different excitation mechanism depending on total optical thickness as well as mean probabilities of quantum yield out of a medium which can be used during parametric accountancy of radiation diffusion in solar prominences [ru

  7. Observation of the Kelvin–Helmholtz Instability in a Solar Prominence

    Science.gov (United States)

    Yang, Heesu; Xu, Zhi; Lim, Eun-Kyung; Kim, Sujin; Cho, Kyung-Suk; Kim, Yeon-Han; Chae, Jongchul; Cho, Kyuhyoun; Ji, Kaifan

    2018-04-01

    Many solar prominences end their lives in eruptions or abrupt disappearances that are associated with dynamical or thermal instabilities. Such instabilities are important because they may be responsible for energy transport and conversion. We present a clear observation of a streaming kink-mode Kelvin–Helmholtz Instability (KHI) taking place in a solar prominence using the Hα Lyot filter installed at the New Vacuum Solar Telescope, Fuxian-lake Solar Observatory in Yunnan, China. On one side of the prominence, a series of plasma blobs floated up from the chromosphere and streamed parallel to the limb. The plasma stream was accelerated to about 20–60 km s‑1 and then undulated. We found that 2″- and 5″-size vortices formed, floated along the stream, and then broke up. After the 5″-size vortex, a plasma ejection out of the stream was detected in the Solar Dynamics Observatory/Atmospheric Imaging Assembly images. Just before the formation of the 5″-size vortex, the stream displayed an oscillatory transverse motion with a period of 255 s with the amplitude growing at the rate of 0.001 s‑1. We attribute this oscillation of the stream and the subsequent formation of the vortex to the KHI triggered by velocity shear between the stream, guided by the magnetic field and the surrounding media. The plasma ejection suggests the transport of prominence material into the upper layer by the KHI in its nonlinear stage.

  8. Flotation process control optimisation at Prominent Hill

    International Nuclear Information System (INIS)

    Lombardi, Josephine; Muhamad, Nur; Weidenbach, M.

    2012-01-01

    OZ Minerals' Prominent Hill copper- gold concentrator is located 130 km south east of the town of Coober Pedy in the Gawler Craton of South Australia. The concentrator was built in 2008 and commenced commercial production in early 2009. The Prominent Hill concentrator is comprised of a conventional grinding and flotation processing plant with a 9.6 Mtpa ore throughput capacity. The flotation circuit includes six rougher cells, an IseMill for regrinding the rougher concentrate and a Jameson cell heading up the three stage conventional cell cleaner circuit. In total there are four level controllers in the rougher train and ten level controllers in the cleaning circuit for 18 cells. Generic proportional — integral and derivative (PID) control used on the level controllers alone propagated any disturbances downstream in the circuit that were generated from the grinding circuit, hoppers, between cells and interconnected banks of cells, having a negative impact on plant performance. To better control such disturbances, FloatStar level stabiliser was selected for installation on the flotation circuit to account for the interaction between the cells. Multivariable control was also installed on the five concentrate hoppers to maintain consistent feed to the cells and to the IsaMill. An additional area identified for optimisation in the flotation circuit was the mass pull rate from the rougher cells. FloatStar flow optimiser was selected to be installed subsequent to the FloatStar level stabiliser. This allowed for a unified, consistent and optimal approach to running the rougher circuit. This paper describes the improvement in the stabilisation of the circuit achieved by the FloatStar level stabiliser by using the interaction matrix between cell level controllers and the results and benefits of implementing the FloatStar flow optimiser on the rougher train.

  9. A model on CME/Flare initiation: Loss of Equilibrium caused by mass loss of quiescent prominences

    Science.gov (United States)

    Miley, George; Chon Nam, Sok; Kim, Mun Song; Kim, Jik Su

    2015-08-01

    Coronal Mass Ejections (CMEs) model should give an answer to enough energy storage for giant bulk plasma into interplanetary space to escape against the sun’s gravitation and its explosive eruption. Advocates of ‘Mass Loading’ model (e.g. Low, B. 1996, SP, 167, 217) suggested a simple mechanism of CME initiation, the loss of mass from a prominence anchoring magnetic flux rope, but they did not associate the mass loss with the loss of equilibrium. The catastrophic loss of equilibrium model is considered as to be a prospective CME/Flare model to explain sudden eruption of magnetic flux systems. Isenberg, P. A., et al (1993, ApJ, 417, 368)developed ideal magnetohydrodynamic theory of the magnetic flux rope to show occurrence of catastrophic loss of equilibrium according to increasing magnetic flux transported into corona.We begin with extending their study including gravity on prominence’s material to obtain equilibrium curves in case of given mass parameters, which are the strengths of the gravitational force compared with the characteristic magnetic force. Furthermore, we study quasi-static evolution of the system including massive prominence flux rope and current sheet below it to obtain equilibrium curves of prominence’s height according to decreasing mass parameter in a properly fixed magnetic environment. The curves show equilibrium loss behaviors to imply that mass loss result in equilibrium loss. Released fractions of magnetic energy are greater than corresponding zero-mass case. This eruption mechanism is expected to be able to apply to the eruptions of quiescent prominences, which is located in relatively weak magnetic environment with 105 km of scale length and 10G of photospheric magnetic field.

  10. Climatic impact of volcanic eruptions

    Science.gov (United States)

    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.

  11. Plasma Brightenings in a Failed Solar Filament Eruption

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Ding, M. D., E-mail: yingli@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China)

    2017-03-20

    Failed filament eruptions are solar eruptions that are not associated with coronal mass ejections. In a failed filament eruption, the filament materials usually show some ascending and falling motions as well as generating bright EUV emissions. Here we report a failed filament eruption (SOL2016-07-22) that occurred in a quiet-Sun region observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . In this event, the filament spreads out but gets confined by the surrounding magnetic field. When interacting with the ambient magnetic field, the filament material brightens up and flows along the magnetic field lines through the corona to the chromosphere. We find that some materials slide down along the lifting magnetic structure containing the filament and impact the chromosphere, and through kinetic energy dissipation, cause two ribbon-like brightenings in a wide temperature range. There is evidence suggesting that magnetic reconnection occurs between the filament magnetic structure and the surrounding magnetic fields where filament plasma is heated to coronal temperatures. In addition, thread-like brightenings show up on top of the erupting magnetic fields at low temperatures, which might be produced by an energy imbalance from a fast drop of radiative cooling due to plasma rarefaction. Thus, this single event of a failed filament eruption shows the existence of a variety of plasma brightenings that may be caused by completely different heating mechanisms.

  12. Dwarf Star Erupts in Giant Flare

    Science.gov (United States)

    2005-01-01

    This movie taken by NASA'S Galaxy Evolution Explorer shows one of the largest flares, or star eruptions, ever recorded at ultraviolet wavelengths. The star, called GJ 3685A, just happened to be in the Galaxy Evolution Explorer's field of view while the telescope was busy observing galaxies. As the movie demonstrates, the seemingly serene star suddenly exploded once, then even more intensely a second time, pouring out in total about one million times more energy than a typical flare from our Sun. The second blast of light constituted an increase in brightness by a factor of at least 10,000. Flares are huge explosions of energy stemming from a single location on a star's surface. They are caused by the brief destruction of a star's magnetic fields. Many types of stars experience them, though old, small, rapidly rotating 'red dwarfs' like GJ 3685A tend to flare more frequently and dramatically. These stars, called flare stars, can experience powerful eruptions as often as every few hours. Younger stars, in general, also erupt more often. One of the reasons astronomers study flare stars is to gain a better picture and history of flare events taking place on the Sun. A preliminary analysis of the GJ 3685A flare shows that the mechanisms underlying stellar eruptions may be more complex than previously believed. Evidence for the two most popular flare theories was found. Though this movie has been sped up (the actual flare lasted about 20 minutes), time-resolved data exist for each one-hundredth of a second. These observations were taken at 2 p.m. Pacific time, April 24, 2004. In the still image, the time sequence starts in the upper left panel, continues in the upper right, then moves to the lower left and ends in the lower right. The circular and linear features that appear below and to the right of GJ 3685A during the flare event are detector artifacts caused by the extreme brightness of the flare.

  13. Volcanic Eruptions in Kamchatka

    Science.gov (United States)

    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 cloud morphology and

  14. Historical Significant Volcanic Eruption Locations

    Data.gov (United States)

    Department of Homeland Security — A significant eruption is classified as one that meets at least one of the following criteriacaused fatalities, caused moderate damage (approximately $1 million or...

  15. The Computational Processing of Intonational Prominence: A Functional Prosody Perspective

    OpenAIRE

    Nakatani, Christine Hisayo

    1997-01-01

    Intonational prominence, or accent, is a fundamental prosodic feature that is said to contribute to discourse meaning. This thesis outlines a new, computational theory of the discourse interpretation of prominence, from a FUNCTIONAL PROSODY perspective. Functional prosody makes the following two important assumptions: first, there is an aspect of prominence interpretation that centrally concerns discourse processes, namely the discourse focusing nature of prominence; and second, the role of p...

  16. Assessing Eruption Column Height in Ancient Flood Basalt Eruptions

    Science.gov (United States)

    Glaze, Lori S.; Self, Stephen; Schmidt, Anja; Hunter, Stephen J.

    2015-01-01

    A buoyant plume model is used to explore the ability of flood basalt eruptions to inject climate-relevant gases into the stratosphere. An example from the 1986 Izu-Oshima basaltic fissure eruption validates the model's ability to reproduce the observed maximum plume heights of 12-16 km above sea level, sustained above fire-fountains. The model predicts maximum plume heights of 13-17 km for source widths of between 4-16 m when 32% (by mass) of the erupted magma is fragmented and involved in the buoyant plume (effective volatile content of 6 wt%). Assuming that the Miocene-age Roza eruption (part of the Columbia River Basalt Group) sustained fire-fountains of similar height to Izu-Oshima (1.6 km above the vent), we show that the Roza eruption could have sustained buoyant ash and gas plumes that extended into the stratosphere at approximately 45 deg N. Assuming 5 km long active fissure segments and 9000 Mt of SO2 released during explosive phases over a 10-15 year duration, the approximately 180 km of known Roza fissure length could have supported approximately 36 explosive events/phases, each with a duration of 3-4 days. Each 5 km fissure segment could have emitted 62 Mt of SO2 per day into the stratosphere while actively fountaining, the equivalent of about three 1991 Mount Pinatubo eruptions per day. Each fissure segment could have had one to several vents, which subsequently produced lava without significant fountaining for a longer period within the decades-long eruption. Sensitivity of plume rise height to ancient atmospheric conditions is explored. Although eruptions in the Deccan Traps (approximately 66 Ma) may have generated buoyant plumes that rose to altitudes in excess of 18 km, they may not have reached the stratosphere because the tropopause was substantially higher in the late Cretaceous. Our results indicate that some flood basalt eruptions, such as Roza, were capable of repeatedly injecting large masses of SO2 into the stratosphere. Thus sustained

  17. Volcanic eruption plumes on Io

    International Nuclear Information System (INIS)

    Strom, R.G.; Terrile, R.J.; Masursky, H.; Hansen, C.

    1979-01-01

    The detection of an umbrella-shaped plume extending about 280 km above the bright limb of Io was one of the most important discoveries made during the Voyager 1 encounter with the jovian system. This discovery proves that Io is volcanically active at present, and the number and magnitude of these eruptions indicate that Io is the most volcanically active body so far discovered in the Solar System. Preliminary analyses of these eruptive plumes are presented. (U.K.)

  18. Old World frog and bird vocalizations contain prominent ultrasonic harmonics

    Science.gov (United States)

    Narins, Peter M.; Feng, Albert S.; Lin, Wenyu; Schnitzler, Hans-Ulrich; Denzinger, Annette; Suthers, Roderick A.; Xu, Chunhe

    2004-02-01

    Several groups of mammals such as bats, dolphins and whales are known to produce ultrasonic signals which are used for navigation and hunting by means of echolocation, as well as for communication. In contrast, frogs and birds produce sounds during night- and day-time hours that are audible to humans; their sounds are so pervasive that together with those of insects, they are considered the primary sounds of nature. Here we show that an Old World frog (Amolops tormotus) and an oscine songbird (Abroscopus albogularis) living near noisy streams reliably produce acoustic signals that contain prominent ultrasonic harmonics. Our findings provide the first evidence that anurans and passerines are capable of generating tonal ultrasonic call components and should stimulate the quest for additional ultrasonic species.

  19. Premature dental eruption: report of case.

    LENUS (Irish Health Repository)

    McNamara, C M

    2011-08-05

    This case report reviews the variability of dental eruption and the possible sequelae. Dental eruption of the permanent teeth in cleft palate children may be variable, with delayed eruption the most common phenomenon. A case of premature dental eruption of a maxillary left first premolar is demonstrated, however, in a five-year-old male. This localized premature dental eruption anomaly was attributed to early extraction of the primary dentition, due to caries.

  20. Modeling lunar volcanic eruptions

    Science.gov (United States)

    Housley, R. M.

    1978-01-01

    Simple physical arguments are used to show that basaltic volcanos on different planetary bodies would fountain to the same height if the mole fraction of gas in the magma scaled with the acceleration of gravity. It is suggested that the actual eruption velocities and fountain heights are controlled by the velocities of sound in the two phase gas/liquid flows. These velocities are in turn determined by the gas contents in the magma. Predicted characteristics of Hawaiian volcanos are in excellent accord with observations. Assuming that the only gas in lunar volcano is the CO which would be produced if the observed Fe metal in lunar basalts resulted from graphite reduction, lunar volcanos would fountain vigorously, but not as spectacularly as their terrestrial counterparts. The volatile trace metals, halogens, and sulfur released would be transported over the entire moon by the transient atmosphere. Orange and black glass type pyroclastic materials would be transported in sufficient amounts to produce the observed dark mantle deposits.

  1. Prominent Optic Disc Featured in Inherited Retinopathy.

    Science.gov (United States)

    Todorova, M G; Bojinova, R I; Valmaggia, C; Schorderet, D F

    2017-04-01

    Background We investigated the relationship between prominent optic disc (POD) and inherited retinal dystrophy (IRD). Patients and Methods A cross-sectional consecutive study was performed in 10 children and 11 adults of 7 non-related families. We performed clinical phenotyping, including a detailed examination, fundus autofluorescence, and colour fundus and OCT imaging. Genetic testing was subsequently performed for all family members presenting retinal pathology. Results In 4 members of a 3-generation family, hyperfluorescent deposits on the surface of POD were related to a p.(L224M) heterozygous mutation in BEST1 . In the second family, one member presented deposits located on the surface on hyperaemic OD and a compound p.(R141H);(A195V) mutation in BEST1 . In the third family, POD was observed in father and child with early onset cone-rod dystrophy and a novel autosomal recessive p.(W31*) homozygous mutation in ABCA4 . In the fourth family, POD with "mulberry-like" deposits and attenuated vessels were observed in a 7-year old girl, with a mutation in USH1A , and with early onset rod-cone dystrophy, associated with hearing loss. In the fifth family, blurry OD with tortuous vessels was observed in 4 consanguineous female carriers and a hemizygous boy with a p.(R200H) mutation in the X-linked retinoschisis RS1 . In the sixth family, a mother and her son were both affected with POD and attenuated peripapillary vessels, and presented with a p.(Y836C) heterozygous mutation in TOPORS , thus confirming autosomal dominant RP. In the seventh family, in 3 family members with POD, compound p.(L541P;A1038 V);(G1961E) mutations in ABCA4 confirmed the diagnosis of Stargardt disease. Conclusions A variety of OD findings are found in a genetically heterogeneous group of IRDs. In the presence of POD, an inherited progressive photoreceptor disease should be ruled out. Georg Thieme Verlag KG Stuttgart · New York.

  2. Morphology Of A Hot Prominence Cavity Observed with Hinode/XRT and SDO/AIA

    Science.gov (United States)

    Weber, Mark A.; Reeves, K. K.; Gibson, S. E.; Kucera, T. A.

    2012-01-01

    Prominence cavities appear as circularly shaped voids in coronal emission over polarity inversion lines where a prominence channel is straddling the solar limb. The presence of chromospheric material suspended at coronal altitudes is a common but not necessary feature within these cavities. These voids are observed to change shape as a prominence feature rotates around the limb. We use a morphological model projected in cross-sections to fit the cavity emission in Hinode/XRT passbands, and then apply temperature diagnostics to XRT and SDO/AIA data to investigate the thermal structure. We find significant evidence that the prominence cavity is hotter than the corona immediately outside the cavity boundary. This investigation follows upon "Thermal Properties of A Solar Coronal Cavity Observed with the X-ray Telescope on Hinode" by Reeves et al., 2012, ApJ, in press.

  3. Eruptions from the Sun

    Science.gov (United States)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  4. A three-dimensional model for solar prominences

    International Nuclear Information System (INIS)

    Demoulin, P.; Priest, E.R.; Anzer, U.

    1989-01-01

    Prominences have been modelled largely as one-or two-dimensional structures, and yet observations show them to possess important variations in the third dimension along the prominence axis with great arches with feet reaching down towards the solar surface. As an initial attempt to understand this structure we consider a three-dimensional linear force-free field model for the global magnetic field around a quiescent prominence. It consists of a fundamental together with a harmonic that is periodic along the prominence. At the solar surface there is a series of flux concentrations spaced out periodically on both sides of the prominence. Between a pair of oppositely directed flux concentration, the magnetic field in the prominence is stronger and tends to be less highly sheared than elsewhere. This modulation of the field strength and shear angle along the prominence decreases with height and almost disappears above 10 Mm. Prominence fields that increase with height occur when the shear is large and the length-scale for field variations perpendicular to the prominence exceeds that along it. The variation of the prominence height along the prominence is calculated and it is suggested that feet occur where the prominence sags down to low heights. For prominences of Normal polarity this tends to occur near supergranule centres where the transverse field is least, whereas for those of Inverse polarity it usually takes place near the chromospheric network where the transverse field is greatest. The effect of concentrating the base flux by including extra harmonics is also included. For Normal polarity prominences it tends to make the foot wider, and for Inverse polarity configurations, it usually creates deeper and narrower feet

  5. Volcanology and hazards of phreatomagmatic basaltic eruptions

    DEFF Research Database (Denmark)

    Schmith, Johanne

    Iceland is one of the most active terrestrial volcanic regions on Earth with an average of more than 20 eruptions per century. Around 80% of all events are tephra generating explosive eruptions, but less than 10 % of all known tephra layers have been mapped. Recent hazard assessment models show...... that the two key parameters for hazard assessment modeling are total grain size distribution (TGSD) and eruptive style. These two parameters have been determined for even fewer eruptive events in Iceland. One of the most hazardous volcanoes in Iceland is Katla and no data set of TGSD or other eruptive...... parameters exist. Katla has not erupted for 99 years, but at least 2 of the 20 eruptions since the settlement of Iceland in 871 have reached Northern Europe as visible tephra fall. These eruptions occurred in 1755 and 1625 and remain enigmatic both in terms of actual size and eruption dynamics. This work...

  6. Case report: pre-eruptive intra-coronal radiolucencies revisited.

    LENUS (Irish Health Repository)

    Counihan, K P

    2012-08-01

    Pre-eruptive intra-coronal radiolucency (PEIR) describes a radiolucent lesion located in the coronal dentine, just beneath the enamel-dentine junction of unerupted teeth. The prevalence of this lesion varies depending on the type and quality of radiographic exposure and age of patients used for assessment. The aetiology of pre-eruptive intra-coronal radiolucent lesions is not fully understood, but published clinical and histological evidence suggest that these lesions are resorptive in nature. Issues around the diagnosis, treatment planning and clinical management of this lesion are explored using previously unreported cases.

  7. The Lusi eruption site: insights from surface and subsurface investigations

    Science.gov (United States)

    Mazzini, A.

    2017-12-01

    The Indonesian Lusi eruption has been spewing boiling water, gas, and sediments since the 29th of May 2006. Initially, numerous aligned eruptions sites appeared along the Watukosek fault system (WFS) that was reactivated after the Yogyakarta earthquake occurring the 27th of May in the Java Island. Within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. To date Lusi is still active and an area of 7 km2is covered by mud. Since its birth Lusi erupted with a pulsating behaviour. In the framework of the ERC grant "Lusi Lab" we conducted several years of monitoring and regional investigations coupling surface sampling and subsurface imaging in the region around Lusi. Ambient noise tomography studies, obtained with a local network of 31 stations, revealed for the first time subsurface images of the Lusi region and the adjacent Arjuno-Welirang (AW) volcanic complex. Results show that below the AW volcanic complex are present 5km deep magma chambers that are connected, through a defined corridor, with the roots of the Lusi eruption site. The Lusi subsurface shows the presence of a defined vertical hydrothermal plume that extends to at least 5km. Chemical analyses of the seeping fluids sampled from 1) the Lusi plume (using a specifically designed drone), 2) the region around Lusi, and 3) the fumaroles and the hydro thermal springs of AW, revealed striking similarities. More specifically a mantellic signature of the Lusi fluids confirms the scenario that Lusi represents a magmatic-driven hydrothermal system hosted in sedimentary basin. Seismic profiles interpretation, surface mapping, and fluid sampling show that the WFS, connecting AW and extending towards the NE of Java, acted as a preferential pathway for the igneous intrusion and fluids migration towards the subsurface. Petrography and dating of the clasts erupted at Lusi record high temperatures and indicate that the roots of the active conduit extend to at least 5km

  8. Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare

    International Nuclear Information System (INIS)

    Li, Y.; Ding, M. D.; Sun, X.; Qiu, J.; Priest, E. R.

    2017-01-01

    Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 2016 March 23 observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . The extreme-ultraviolet imaging observations exhibit the clear rise and eruption of an MFR. In particular, the observations reveal solid evidence of magnetic reconnection from both the corona and chromosphere during the flare. Moreover, weak reconnection is observed before the start of the flare. We find that the preflare weak reconnection is of tether-cutting type and helps the MFR to rise slowly. Induced by a further rise of the MFR, strong reconnection occurs in the rise phases of the flare, which is temporally related to the MFR eruption. We also find that the magnetic reconnection is more of 3D-type in the early phase, as manifested in a strong-to-weak shear transition in flare loops, and becomes more 2D-like in the later phase, as shown by the apparent rising motion of an arcade of flare loops.

  9. Imaging Observations of Magnetic Reconnection in a Solar Eruptive Flare

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Ding, M. D. [School of Astronomy and Space Science, Nanjing University, Nanjing 210023 (China); Sun, X. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Qiu, J. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Priest, E. R., E-mail: yingli@nju.edu.cn [School of Mathematics and Statistics, University of St Andrews, Fife KY16 9SS, Scotland (United Kingdom)

    2017-02-01

    Solar flares are among the most energetic events in the solar atmosphere. It is widely accepted that flares are powered by magnetic reconnection in the corona. An eruptive flare is usually accompanied by a coronal mass ejection, both of which are probably driven by the eruption of a magnetic flux rope (MFR). Here we report an eruptive flare on 2016 March 23 observed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory . The extreme-ultraviolet imaging observations exhibit the clear rise and eruption of an MFR. In particular, the observations reveal solid evidence of magnetic reconnection from both the corona and chromosphere during the flare. Moreover, weak reconnection is observed before the start of the flare. We find that the preflare weak reconnection is of tether-cutting type and helps the MFR to rise slowly. Induced by a further rise of the MFR, strong reconnection occurs in the rise phases of the flare, which is temporally related to the MFR eruption. We also find that the magnetic reconnection is more of 3D-type in the early phase, as manifested in a strong-to-weak shear transition in flare loops, and becomes more 2D-like in the later phase, as shown by the apparent rising motion of an arcade of flare loops.

  10. Understanding the eruption mechanisms of the explosive Bellecombe Eruptions on Piton de la Fournaise, La Réunion

    Science.gov (United States)

    Morgan, K.; Ort, M. H.; Di Muro, A.; Parnell, R. A.; Huff, W. D.

    2017-12-01

    Piton de la Fournaise (PdF) is an active basaltic volcano on La Réunion island. The Bellecombe Tephra was deposited from at least three unusually explosive eruptions between 3000-5000 ka. The Bellecombe eruptions were interpreted recently to have been due to rapid depressurization of the hydrothermal system when a deep fracture opened after lateral, seaward-directed sliding of the eastern flank, late in a large effusive eruption. This project tests this hypothesis by physically, mineralogically, and chemically characterizing the Bellecombe Tephra to look for evidence of the involvement of the PdF hydrothermal system in the eruptions and understand where the eruptions initiated. The Bellecombe tephra consists of three units separated by incipient soils. Both the Upper and Lower Bellecombe deposits are mostly medium to very fine ash. Lower Bellecombe deposits, from the first two eruptions, are mostly beds of glassy ash containing minor lithic grains and olivine crystals. Hydrothermal minerals, mostly smectite, are present in a few Lower Bellecombe beds. Since these minerals are only present in some beds, the smectite formed before deposition rather than as a product of surficial alteration. The Upper Bellecombe deposits record a third eruption and vary between clast-supported crystal- and lithic-rich lapilli beds and ash beds with abundant ash pellets. The crystals are mostly olivine, with lesser pyroxene and plagioclase and sparse hydrothermal quartz. Gabbro and oceanite clasts are abundant and trachytic pumice rare in these deposits. Hydrothermal minerals are common in most Upper Bellecombe beds. The presence of smectite in some of the Lower Bellecombe beds suggests these deposits came from a system below 200 ºC. Clays in the Upper Bellecombe beds - smectite and mixed layer R0 illite/smectite - imply a system at 40-140 ºC. The hydrothermal system was involved, but might not have been the primary impetus for these eruptions, since hydrothermal minerals are not

  11. Evident?

    DEFF Research Database (Denmark)

    Plant, Peter

    2012-01-01

    Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind......Quality assurance and evidence in career guidance in Europe are often seen as self-evident approaches, but particular interests lie behind...

  12. Pyroclast textural variation as an indicator of eruption column steadiness in andesitic Plinian eruptions at Mt. Ruapehu

    Science.gov (United States)

    Pardo, Natalia; Cronin, Shane J.; Wright, Heather M.N.; Schipper, C. Ian; Smith, Ian; Stewart, Bob

    2014-01-01

    Between 27 and 11 cal. ka BP, a transition is observed in Plinian eruptions at Mt. Ruapehu, indicating evolution from non-collapsing (steady and oscillatory) eruption columns to partially collapsing columns (both wet and dry). To determine the causes of these variations over this eruptive interval, we examined lapilli fall deposits from four eruptions representing the climactic phases of each column type. All eruptions involve andesite to basaltic andesite magmas containing plagioclase, clinopyroxene, orthopyroxene and magnetite phenocrysts. Differences occur in the dominant pumice texture, the degree of bulk chemistry and textural variability, the average microcrystallinity and the composition of groundmass glass. In order to investigate the role of ascent and degassing processes on column stability, vesicle textures were quantified by gas volume pycnometry (porosity), X-ray synchrotron and computed microtomography (μ-CT) imagery from representative clasts from each eruption. These data were linked to groundmass crystallinity and glass geochemistry. Pumice textures were classified into six types (foamy, sheared, fibrous, microvesicular, microsheared and dense) according to the vesicle content, size and shape and microlite content. Bulk porosities vary from 19 to 95 % among all textural types. Melt-referenced vesicle number density ranges between 1.8 × 102 and 8.9 × 102 mm−3, except in fibrous textures, where it spans from 0.3 × 102 to 53 × 102 mm−3. Vesicle-free magnetite number density varies within an order of magnitude from 0.4 × 102 to 4.5 × 102 mm−3 in samples with dacitic groundmass glass and between 0.0 and 2.3 × 102 mm−3 in samples with rhyolitic groundmass. The data indicate that columns that collapsed to produce pyroclastic flows contained pumice with the greatest variation in bulk composition (which overlaps with but extends to slightly more silicic compositions than other eruptive products); textures

  13. Enhancement of eruption explosivity by heterogeneous bubble nucleation triggered by magma mingling.

    Science.gov (United States)

    Paredes-Mariño, Joali; Dobson, Katherine J; Ortenzi, Gianluigi; Kueppers, Ulrich; Morgavi, Daniele; Petrelli, Maurizio; Hess, Kai-Uwe; Laeger, Kathrin; Porreca, Massimiliano; Pimentel, Adriano; Perugini, Diego

    2017-12-04

    We present new evidence that shows magma mingling can be a key process during highly explosive eruptions. Using fractal analysis of the size distribution of trachybasaltic fragments found on the inner walls of bubbles in trachytic pumices, we show that the more mafic component underwent fracturing during quenching against the trachyte. We propose a new mechanism for how this magmatic interaction at depth triggered rapid heterogeneous bubble nucleation and growth and could have enhanced eruption explosivity. We argue that the data support a further, and hitherto unreported contribution of magma mingling to highly explosive eruptions. This has implications for hazard assessment for those volcanoes in which evidence of magma mingling exists.

  14. Io - One of at Least Four Simultaneous Erupting Volcanic Eruptions

    Science.gov (United States)

    1979-01-01

    This photo of an active volcanic eruption on Jupiter's satellite Io was taken 1 hour, 52 minutes after the accompanying picture, late in the evening of March 4, 1979, Pacific time. On the limb of the satellite can be seen one of at least four simultaneous volcanic eruptions -- the first such activity ever observed on another celestial body. Seen against the limb are plume-like structures rising more than 60 miles (100 kilometers) above the surface. Several eruptions have been identified with volcanic structures on the surface of Io, which have also been identified by Voyager 1's infrared instrument as being abnormally hot -- several hundred degrees warmer than surrounding terrain. The fact that several eruptions appear to be occurring at the same time suggests that Io has the most active surface in the solar system and that volcanism is going on there essentially continuously. Another characteristic of the observed volcanism is that it appears to be extremely explosive, with velocities more than 2,000 miles an hour (at least 1 kilometer per second). That is more violent than terrestrial volcanoes like Etna, Vesuvius or Krakatoa.

  15. Magmatic Ascent and Eruption Processes on Mercury

    Science.gov (United States)

    Head, J. W.; Wilson, L.

    2018-05-01

    MESSENGER volcanic landform data and information on crustal composition allow us to model the generation, ascent, and eruption of magma; Mercury explosive and effusive eruption processes differ significantly from other terrestrial planetary bodies.

  16. Volcanic eruptions are cooling the earth

    International Nuclear Information System (INIS)

    Groenaas, Sigbjoern

    2005-01-01

    The article discusses how volcanic eruptions may influence the climate. The environmental impacts both on the earth surface and the atmosphere are surveyed. Some major eruptions in modern times are mentioned

  17. Two Scenarios for the Eruption of Magnetic Flux Ropes in the Solar Atmosphere

    Science.gov (United States)

    Filippov, B. P.; Den, O. E.

    2018-05-01

    Eruptions of material from lower to upper layers of the solar atmosphere can be divided into two classes. The first class of eruptions maintain their (usually loop-like) shapes as they increase in size (eruptive prominences), or display a sudden expansion of fairly shapeless clumps of plasma in all directions (flare sprays). The second class refers to narrow, collimated flows of plasma on various scales (spicules, surges, jets). It is obvious that the magnetic configurations in which these phenomena develop differ: for the first class they form closed structures that confine the plasma, and in the second class open structures directing flows of plasma in a particular direction, as a rule, upward. At the same time, the mechanisms initiating eruptions of both classes could be similar, or even practically identical. This mechanism could be instability of twisted magnetic tubes (flux ropes), leading to different consequences under different conditions. It is shown that the results of eruptive instability are determined by the ratio of the scales of the magnetic flux rope and the confining coronal field, and also by the configuration of the ambient magnetic field in the corona. Observations of both types of eruptions are analyzed, the conditions for their develoment are examined, and phenomenological models are proposed.

  18. An Unusual Case Report of Erupted Odontoma

    Directory of Open Access Journals (Sweden)

    Dhaval Mehta

    2013-01-01

    Full Text Available Odontomas are the most common of the odontogenic tumors of the jaws, which are benign, slow growing, and nonaggressive. They are usually asymptomatic and found in routine dental radiographic examination. Odontomas are usually associated with tooth eruption disturbances. Eruption of odontoma in oral cavity is rare entity. Here we report a case of an unusual erupted compound odontoma.

  19. Eruption Cyst in the Neonate.

    Science.gov (United States)

    de Oliveira, Alline J; Silveira, Maria Lg; Duarte, Danilo A; Diniz, Michele B

    2018-01-01

    The pediatric dental approach to the oral cavity of newborns requires special attention, as many aspects are unique and peculiar to this period of life. It is important that pediatricians and pediatric dentists be aware of the characteristics within normal newborn patterns and prepared to make a correct diagnosis of abnormalities at early stages. Congenital eruption cysts (ECs) are rarely observed in newborns, as at this stage of a child's life, tooth eruption is unusual. This study reports a case of EC treated successfully by monitoring of the lesion, without any surgical procedure. In the 4th month, the lesion had completely regressed, and the deciduous central incisors had erupted without problems. The clinical and radiographic monitoring of ECs in newborns seems to be a satisfactory management procedure, similar to what is recommended for older children. How to cite this article: de Oliveira AJ, Silveira MLG, Duarte DA, Diniz MB. Eruption Cyst in the Neonate. Int J Clin Pediatr Dent 2018;11(1):58-60.

  20. Eruptive viscosity and volcano morphology

    International Nuclear Information System (INIS)

    Posin, S.B.; Greeley, R.

    1988-01-01

    Terrestrial central volcanoes formed predominantly from lava flows were classified as shields, stratovolcanoes, and domes. Shield volcanoes tend to be large in areal extent, have convex slopes, and are characterized by their resemblance to inverted hellenic war shields. Stratovolcanoes have concave slopes, whereas domes are smaller and have gentle convex slopes near the vent that increase near the perimeter. In addition to these differences in morphology, several other variations were observed. The most important is composition: shield volcanoes tend to be basaltic, stratovolcanoes tend to be andesitic, and domes tend to be dacitic. However, important exceptions include Fuji, Pico, Mayon, Izalco, and Fuego which have stratovolcano morphologies but are composed of basaltic lavas. Similarly, Ribkwo is a Kenyan shield volcano composed of trachyte and Suswa and Kilombe are shields composed of phonolite. These exceptions indicate that eruptive conditions, rather than composition, may be the primary factors that determine volcano morphology. The objective of this study is to determine the relationships, if any, between eruptive conditions (viscosity, erupted volume, and effusion rate) and effusive volcano morphology. Moreover, it is the goal of this study to incorporate these relationships into a model to predict the eruptive conditions of extraterrestrial (Martian) volcanoes based on their morphology

  1. QUIESCENT PROMINENCES IN THE ERA OF ALMA: SIMULATED OBSERVATIONS USING THE 3D WHOLE-PROMINENCE FINE STRUCTURE MODEL

    Energy Technology Data Exchange (ETDEWEB)

    Gunár, Stanislav; Heinzel, Petr [Astronomical Institute, The Czech Academy of Sciences, 25165 Ondřejov (Czech Republic); Mackay, Duncan H. [School of Mathematics and Statistics, University of St Andrews, North Haugh, St Andrews KY16 9SS (United Kingdom); Anzer, Ulrich [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, D-85740 Garching bei München (Germany)

    2016-12-20

    We use the detailed 3D whole-prominence fine structure model to produce the first simulated high-resolution ALMA observations of a modeled quiescent solar prominence. The maps of synthetic brightness temperature and optical thickness shown in the present paper are produced using a visualization method for synthesis of the submillimeter/millimeter radio continua. We have obtained the simulated observations of both the prominence at the limb and the filament on the disk at wavelengths covering a broad range that encompasses the full potential of ALMA. We demonstrate here extent to which the small-scale and large-scale prominence and filament structures will be visible in the ALMA observations spanning both the optically thin and thick regimes. We analyze the relationship between the brightness and kinetic temperature of the prominence plasma. We also illustrate the opportunities ALMA will provide for studying the thermal structure of the prominence plasma from the cores of the cool prominence fine structure to the prominence–corona transition region. In addition, we show that detailed 3D modeling of entire prominences with their numerous fine structures will be important for the correct interpretation of future ALMA observations of prominences.

  2. Imaging a Magnetic-breakout Solar Eruption

    Science.gov (United States)

    Chen, Yao; Du, Guohui; Zhao, Di; Wu, Zhao; Liu, Wei; Wang, Bing; Ruan, Guiping; Feng, Shiwei; Song, Hongqiang

    2016-04-01

    The fundamental mechanism initiating coronal mass ejections (CMEs) remains controversial. One of the leading theories is magnetic breakout, in which magnetic reconnection occurring high in the corona removes the confinement on an energized low-corona structure from the overlying magnetic field, thus allowing it to erupt. Here, we report critical observational evidence of this elusive breakout reconnection in a multi-polar magnetic configuration that leads to a CME and an X-class, long-duration flare. Its occurrence is supported by the presence of pairs of heated cusp-shaped loops around an X-type null point and signatures of reconnection inflows. Other peculiar features new to the breakout picture include sequential loop brightening, coronal hard X-rays at energies up to ˜100 keV, and extended high-corona X-rays above the later restored multi-polar structure. These observations, from a novel perspective with clarity never achieved before, present crucial clues to understanding the initiation mechanism of solar eruptions.

  3. IMAGING A MAGNETIC-BREAKOUT SOLAR ERUPTION

    International Nuclear Information System (INIS)

    Chen, Yao; Du, Guohui; Zhao, Di; Wu, Zhao; Wang, Bing; Ruan, Guiping; Feng, Shiwei; Song, Hongqiang; Liu, Wei

    2016-01-01

    The fundamental mechanism initiating coronal mass ejections (CMEs) remains controversial. One of the leading theories is magnetic breakout, in which magnetic reconnection occurring high in the corona removes the confinement on an energized low-corona structure from the overlying magnetic field, thus allowing it to erupt. Here, we report critical observational evidence of this elusive breakout reconnection in a multi-polar magnetic configuration that leads to a CME and an X-class, long-duration flare. Its occurrence is supported by the presence of pairs of heated cusp-shaped loops around an X-type null point and signatures of reconnection inflows. Other peculiar features new to the breakout picture include sequential loop brightening, coronal hard X-rays at energies up to ∼100 keV, and extended high-corona X-rays above the later restored multi-polar structure. These observations, from a novel perspective with clarity never achieved before, present crucial clues to understanding the initiation mechanism of solar eruptions

  4. The Run-up to Volcanic Eruption Unveiled by Forensic Petrology and Geophysical Observations

    Science.gov (United States)

    Rasmussen, D. J.; Plank, T. A.; Roman, D. C.

    2017-12-01

    Volcanoes often warn of impending eruptions. However, one of the greatest challenges in volcano research is translating precursory geophysical signals into physical magmatic processes. Petrology offers powerful tools to study eruption run-up that benefit from direct response to magmatic forcings. Developing these tools, and tying them to geophysical observations, will help us identify eruption triggers (e.g., magmatic recharge, gas build-up, tectonic events) and understand the significance of monitored signals of unrest. We present an overview of petrologic tools used for studying eruption run-up, highlighting results from our study of the 1999 eruption of Shishaldin volcano. Olivine crystals contain chemical gradients, the consequence of diffusion following magma mixing events, which is modeled to determine mixing timescales. Modeled timescales provide strong evidence for at least three mixing events, which were triggered by magmatic recharge. Petrologic barometers indicate these events occurred at very shallow depths (within the volcanic edifice). The first mixing event occurred nine months before eruption, which was signaled by a swarm of deep-long period earthquake. Minor recharge events followed over two months, which are indicated by a second deep-long period earthquake swarm and a change in the local stress orientation measured by shear-wave splitting. Following these events, the system was relatively quiet until a large mixing event occurred 45 days prior to eruption, which was heralded by a large earthquake (M5.2). Following this event, geophysical signals of unrest intensified and became continuous. The final mixing event, beginning roughly a week before eruption, represents the final perturbation to the system before eruption. Our findings point to a relatively long run-up, which was subtle at first and intensified several weeks before eruption. This study highlights the strong link between geophysical signals of volcanic unrest and magmatic events, and

  5. Combined surgical management of mandibular angle prominence and microgenia

    International Nuclear Information System (INIS)

    Portelles Masso, Ayelen Maria; Berger Kohn, Carlos

    2010-01-01

    Chin play a very important role in facial aesthetics. Different deformities of volume and of position may occur at this level and it is the microgenia one of the more frequent. Treatment options include the use of silicone, alloplasty materials and autologous bone graft. Authors report the use of the bone removed from mandibular angle to increase the chin. This is the case of a white female patient aged 18 seen by the Orthognathics Multidisciplinary Staff of 'V. I. Lenin' Hospital due to its uncommon face width. The corresponding physical examination as well as the complementary ones diagnosed a bilateral prominence of mandibular angle associated with a microgenia. Surgery carried out was of remodeling type of both mandibular angles and genioplasty of height increase and a discrete advancement using the bone removed from the gonion. There were satisfactory aesthetic results without evidence of bone reabsorption. We conclude that use of autologous graft of mandibular angle is an effective treatment alternative for correction of microgenia. (author)

  6. Regional early development and eruption of permanent teeth: case report.

    Science.gov (United States)

    Al Mullahi, A M; Bakathir, A; Al Jahdhami, S

    2017-02-01

    Early development and eruption of permanent teeth are rarely reported in scientific literature. Early eruption of permanent teeth has been reported to occur due to local factors such as trauma or dental abscesses in primary teeth, and in systemic conditions. Congenital diffuse infiltrating facial lipomatosis (CDIFL) is a rare condition that belongs to a group of lipomatosis tumours. In this disorder, the mature adipocytes invade adjacent soft and hard tissues in the facial region. Accelerated tooth eruption is one of the dental anomalies associated with CDIFL. A 3-year-old boy presented with a swelling of the lower lip localised early development and eruption of permanent teeth and dental caries involving many primary teeth. The planned treatment included biopsy of the swollen lower lip to confirm the diagnosis, surgical reduction and reconstruction of lip aesthetics. The management of the carious primary teeth included preventative and comprehensive dental care and extractions. These procedures were completed under general anaesthesia due to the child's young age and poor cooperation. The lip biopsy showed features of CDIFL such as the presence of infiltrating adipose tissue, prominent number of nerve bundles and thickened vessels. The high recurrence rate of CDIFL mandates long-term monitoring during the facial growth period of the child. Follow-up care by the paediatric dentist and maxillofacial surgeon has been required to manage all aspects of this congenital malformation. This rare disorder has many implications affecting child's facial aesthetics, psychological well being, developing occlusion and risk of dental caries. A multi-disciplinary approach is needed for management of this condition.

  7. Prediction of Solar Eruptions Using Filament Metadata

    Science.gov (United States)

    Aggarwal, Ashna; Schanche, Nicole; Reeves, Katharine K.; Kempton, Dustin; Angryk, Rafal

    2018-05-01

    We perform a statistical analysis of erupting and non-erupting solar filaments to determine the properties related to the eruption potential. In order to perform this study, we correlate filament eruptions documented in the Heliophysics Event Knowledgebase (HEK) with HEK filaments that have been grouped together using a spatiotemporal tracking algorithm. The HEK provides metadata about each filament instance, including values for length, area, tilt, and chirality. We add additional metadata properties such as the distance from the nearest active region and the magnetic field decay index. We compare trends in the metadata from erupting and non-erupting filament tracks to discover which properties present signs of an eruption. We find that a change in filament length over time is the most important factor in discriminating between erupting and non-erupting filament tracks, with erupting tracks being more likely to have decreasing length. We attempt to find an ensemble of predictive filament metadata using a Random Forest Classifier approach, but find the probability of correctly predicting an eruption with the current metadata is only slightly better than chance.

  8. ON THE RELATIONSHIP BETWEEN A HOT-CHANNEL-LIKE SOLAR MAGNETIC FLUX ROPE AND ITS EMBEDDED PROMINENCE

    International Nuclear Information System (INIS)

    Cheng, X.; Ding, M. D.; Zhang, J.; Guo, Y.; Chen, P. F.; Sun, J. Q.; Srivastava, A. K.

    2014-01-01

    A magnetic flux rope (MFR) is a coherent and helical magnetic field structure that has recently been found likely to appear as an elongated hot channel prior to a solar eruption. In this Letter, we investigate the relationship between the hot channel and the associated prominence through analysis of a limb event on 2011 September 12. In the early rise phase, the hot channel was initially cospatial with the prominence. It then quickly expanded, resulting in a separation of the top of the hot channel from that of the prominence. Meanwhile, they both experienced an instantaneous morphology transformation from a Λ shape to a reversed-Y shape and the top of these two structures showed an exponential increase in height. These features are a good indication of the occurrence of kink instability. Moreover, the onset of kink instability is found to coincide in time with the impulsive enhancement of flare emission underneath the hot channel, suggesting that ideal kink instability likely also plays an important role in triggering fast flare reconnection besides initiating the impulsive acceleration of the hot channel and distorting its morphology. We conclude that the hot channel is most likely the MFR system and the prominence only corresponds to the cool materials that are collected in the bottom of the helical field lines of the MFR against gravity

  9. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    International Nuclear Information System (INIS)

    Luna, M.; Moreno-Insertis, F.; Priest, E.

    2015-01-01

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present

  10. Are Tornado-Like Magnetic Structures Able to Support Solar Prominence Plasma?

    Science.gov (United States)

    Ogunjo, S. T.; Luna Bennasar, M.; Moreno-Insertis, F.; Priest, E. R.

    2015-12-01

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  11. ARE TORNADO-LIKE MAGNETIC STRUCTURES ABLE TO SUPPORT SOLAR PROMINENCE PLASMA?

    Energy Technology Data Exchange (ETDEWEB)

    Luna, M.; Moreno-Insertis, F. [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain); Priest, E. [Mathematics Institute, University of St Andrews, St Andrews KY16 9SS (United Kingdom)

    2015-07-20

    Recent high-resolution and high-cadence observations have surprisingly suggested that prominence barbs exhibit apparent rotating motions suggestive of a tornado-like structure. Additional evidence has been provided by Doppler measurements. The observations reveal opposite velocities for both hot and cool plasma on the two sides of a prominence barb. This motion is persistent for several hours and has been interpreted in terms of rotational motion of prominence feet. Several authors suggest that such barb motions are rotating helical structures around a vertical axis similar to tornadoes on Earth. One of the difficulties of such a proposal is how to support cool prominence plasma in almost-vertical structures against gravity. In this work we model analytically a tornado-like structure and try to determine possible mechanisms to support the prominence plasma. We have found that the Lorentz force can indeed support the barb plasma provided the magnetic structure is sufficiently twisted and/or significant poloidal flows are present.

  12. Importance of nanoparticles and colloids from volcanic ash for riverine transport of trace elements to the ocean: evidence from glacial-fed rivers after the 2010 eruption of Eyjafjallajökull Volcano, Iceland.

    Science.gov (United States)

    Tepe, Nathalie; Bau, Michael

    2014-08-01

    Volcanic ashes are often referenced as examples for natural nanoparticles, yet the particle size distribution eruptions at Eyjafjallajökull in 2010. In addition to the dissolved concentrations of rare earth elements (REE), Zr, Hf, Nb, and Th in the 450 nm-filtered waters, we also studied the respective filter residues (river particulates >450 nm) and volcanic ash. In spite of the low solubilities and high particle-reactivities of the elements studied, most water samples show high dissolved concentrations, such as up to 971 ng/kg of Ce and 501 ng/kg of Zr. Except for the pure glacial meltwater and glacial base flow, all waters display the same shale-normalized REE patterns with pronounced light and heavy REE depletion and positive Eu anomalies. While such patterns are unusual for river waters, they are similar to those of the respective river particulates and the volcanic ash, though at different concentration levels. The distribution of dissolved Zr, Hf, Nb, and Th in the waters also matches that of filter residues and ash. This strongly suggests that in all 450 nm-filtered river waters, the elements studied are associated with solid ash particles smaller than 450 nm. This reveals that volcanic ash-derived nanoparticles and colloids are present in these glacial-fed rivers and that such ultrafine particles control the trace element distribution in the surface runoff. Subsequent to explosive volcanic eruptions, these waters provide terrigenous input from landmasses to estuaries, that is characterized by a unique trace element signature and that subsequent to modification by estuarine processes delivers a pulse of nutrients to coastal seawater in regions not affected by plume fall-out. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Ghost Remains After Black Hole Eruption

    Science.gov (United States)

    2009-05-01

    NASA's Chandra X-ray Observatory has found a cosmic "ghost" lurking around a distant supermassive black hole. This is the first detection of such a high-energy apparition, and scientists think it is evidence of a huge eruption produced by the black hole. This discovery presents astronomers with a valuable opportunity to observe phenomena that occurred when the Universe was very young. The X-ray ghost, so-called because a diffuse X-ray source has remained after other radiation from the outburst has died away, is in the Chandra Deep Field-North, one of the deepest X-ray images ever taken. The source, a.k.a. HDF 130, is over 10 billion light years away and existed at a time 3 billion years after the Big Bang, when galaxies and black holes were forming at a high rate. "We'd seen this fuzzy object a few years ago, but didn't realize until now that we were seeing a ghost", said Andy Fabian of the Cambridge University in the United Kingdom. "It's not out there to haunt us, rather it's telling us something - in this case what was happening in this galaxy billions of year ago." Fabian and colleagues think the X-ray glow from HDF 130 is evidence for a powerful outburst from its central black hole in the form of jets of energetic particles traveling at almost the speed of light. When the eruption was ongoing, it produced prodigious amounts of radio and X-radiation, but after several million years, the radio signal faded from view as the electrons radiated away their energy. HDF 130 Chandra X-ray Image of HDF 130 However, less energetic electrons can still produce X-rays by interacting with the pervasive sea of photons remaining from the Big Bang - the cosmic background radiation. Collisions between these electrons and the background photons can impart enough energy to the photons to boost them into the X-ray energy band. This process produces an extended X-ray source that lasts for another 30 million years or so. "This ghost tells us about the black hole's eruption long after

  14. Volcanic eruptions and solar activity

    Science.gov (United States)

    Stothers, Richard B.

    1989-01-01

    The historical record of large volcanic eruptions from 1500 to 1980 is subjected to detailed time series analysis. In two weak but probably statistically significant periodicities of about 11 and 80 yr, the frequency of volcanic eruptions increases (decreases) slightly around the times of solar minimum (maximum). Time series analysis of the volcanogenic acidities in a deep ice core from Greenland reveals several very long periods ranging from about 80 to about 350 yr which are similar to the very slow solar cycles previously detected in auroral and C-14 records. Solar flares may cause changes in atmospheric circulation patterns that abruptly alter the earth's spin. The resulting jolt probably triggers small earthquakes which affect volcanism.

  15. Assessing hazards to aviation from sulfur dioxide emitted by explosive Icelandic eruptions

    OpenAIRE

    Schmidt, A; Witham, CS; Theys, N; Richards, NAD; Thordarson, T; Szpek, K; Feng, W; Hort, MC; Woolley, AM; Jones, AR; Redington, AL; Johnson, BT; Hayward, CL; Carslaw, KS

    2014-01-01

    Volcanic eruptions take place in Iceland about once every 3 to 5 years. Ash emissions from these eruptions can cause significant disruption to air traffic over Europe and the North Atlantic as is evident from the 2010 eruption of Eyjafjallajökull. Sulfur dioxide (SO2) is also emitted by volcanoes, but there are no criteria to define when airspace is considered hazardous or nonhazardous. However, SO2 is a well-known ground-level pollutant that can have detrimental effects on human health. We h...

  16. Tooth eruption and browridge formation.

    Science.gov (United States)

    Russell, M D

    1982-05-01

    One of the most reasonable hypotheses regarding the functional significance of the browridge is that the supraorbital torus forms in response to masticatory stress during development. Oyen, Walker, and Rice (1979) have recently proposed a model that tests this hypothesis: if browridges are functionally related to masticatory stresses on the cranial vault, then changes in the biomechanics of the masticatory system ought to be reflected by changes in the browridge. To test their model they attempted to relate biomechanical discontinuities resulting from tooth eruption to episodes of bone deposition on the supraorbital tori of a developmental series of dry Papio crania. This paper reports on a parallel test of the model on a cross-sectional sample of Australian Aboriginal juvenile crania. This sample showed no relation between tooth eruption and the supraorbital surface morphology thought to be indicative of active bone deposition. It is also demonstrated that no significant relationship between tooth eruption and episodes of bone deposition is shown by the Papio sample. It is concluded that the use of small cross-sectional samples of dry crania does not provide a valid test of the model.

  17. Morphology, temperature, and eruption dynamics at Pele

    Science.gov (United States)

    Howell, Robert R.; Lopes, Rosaly M. C.

    2011-06-01

    ., Milazzo, M., Radebaugh, J., Davies, A.G., Mitchell, K.L. [2007]. Icarus 192, 491-502). When applied to the I32 observations we obtain a fire-fountain mass eruption rate of 5.1 × 10 5 kg s -1 for the main vent area and 1.4 × 10 4 kg s -1 for each of two smaller vent regions to the west. These fire-fountain rates suggest a solution to the puzzling lack of extensive lava flows in the Pele region. Much of the erupted lava may be ejected at high speed into the fire-fountains and plumes, creating dispersed pyroclastic deposits rather than flows. We compare gas and silicate mass eruption rates and discuss briefly the dynamics of this ejection model and the observational evidence.

  18. Eruptive and Geomorphic Processes at the Lathrop Wells Scoria Cone

    International Nuclear Information System (INIS)

    G. Valentine; D.J. Krier; F.V. Perry; G. Heiken

    2006-01-01

    The ∼80 ka Lathrop Wells volcano (southern Nevada, U.S.A.) preserves evidence for a range of explosive processes and emplacement mechanisms of pyroclastic deposits and lava fields in a small-volume basaltic center. Early cone building by Strombolian bursts was accompanied by development of a fan-like lava field reaching ∼800 m distance from the cone, built upon a gently sloping surface. Lava flows carried rafts of cone deposits, which provide indirect evidence for cone facies in lieu of direct exposures in the active quarry. Subsequent activity was of a violent Strombolian nature, with many episodes of sustained eruption columns up to a few km in height. These deposited layers of scoria lapilli and ash in different directions depending upon wind direction at the time of a given episode, reaching up to ∼20 km from the vent, and also produced the bulk of the scoria cone. Lava effusion migrated from south to north around the eastern base of the cone as accumulation of lavas successively reversed the topography at the base of the cone. Late lavas were emplaced during violent Strombolian activity and continued for some time after explosive eruptions had waned. Volumes of the eruptive products are: fallout--0.07 km 3 , scoria cone--0.02 km 3 , and lavas--0.03 km 3 . Shallow-derived xenolith concentrations suggest an upper bound on average conduit diameter of ∼21 m in the uppermost 335 m beneath the volcano. The volcano was constructed over a period of at least seven months with cone building occurring only during part of that time, based upon analogy with historical eruptions. Post-eruptive geomorphic evolution varied for the three main surface types that were produced by volcanic activity: (1) scoria cone, (2) low relief surfaces (including lavas) with abundant pyroclastic material, and (3) lavas with little pyroclastic material. The role of these different initial textures must be accounted for in estimating relative ages of volcanic surfaces, and failure to

  19. Eruptive and Geomorphic Processes at the Lathrop Wells Scoria Cone

    Energy Technology Data Exchange (ETDEWEB)

    G. Valentine; D.J. Krier; F.V. Perry; G. Heiken

    2006-08-03

    The {approx}80 ka Lathrop Wells volcano (southern Nevada, U.S.A.) preserves evidence for a range of explosive processes and emplacement mechanisms of pyroclastic deposits and lava fields in a small-volume basaltic center. Early cone building by Strombolian bursts was accompanied by development of a fan-like lava field reaching {approx}800 m distance from the cone, built upon a gently sloping surface. Lava flows carried rafts of cone deposits, which provide indirect evidence for cone facies in lieu of direct exposures in the active quarry. Subsequent activity was of a violent Strombolian nature, with many episodes of sustained eruption columns up to a few km in height. These deposited layers of scoria lapilli and ash in different directions depending upon wind direction at the time of a given episode, reaching up to {approx}20 km from the vent, and also produced the bulk of the scoria cone. Lava effusion migrated from south to north around the eastern base of the cone as accumulation of lavas successively reversed the topography at the base of the cone. Late lavas were emplaced during violent Strombolian activity and continued for some time after explosive eruptions had waned. Volumes of the eruptive products are: fallout--0.07 km{sup 3}, scoria cone--0.02 km{sup 3}, and lavas--0.03 km{sup 3}. Shallow-derived xenolith concentrations suggest an upper bound on average conduit diameter of {approx}21 m in the uppermost 335 m beneath the volcano. The volcano was constructed over a period of at least seven months with cone building occurring only during part of that time, based upon analogy with historical eruptions. Post-eruptive geomorphic evolution varied for the three main surface types that were produced by volcanic activity: (1) scoria cone, (2) low relief surfaces (including lavas) with abundant pyroclastic material, and (3) lavas with little pyroclastic material. The role of these different initial textures must be accounted for in estimating relative ages of

  20. A submarine volcanic eruption leads to a novel microbial habitat.

    Science.gov (United States)

    Danovaro, Roberto; Canals, Miquel; Tangherlini, Michael; Dell'Anno, Antonio; Gambi, Cristina; Lastras, Galderic; Amblas, David; Sanchez-Vidal, Anna; Frigola, Jaime; Calafat, Antoni M; Pedrosa-Pàmies, Rut; Rivera, Jesus; Rayo, Xavier; Corinaldesi, Cinzia

    2017-04-24

    Submarine volcanic eruptions are major catastrophic events that allow investigation of the colonization mechanisms of newly formed seabed. We explored the seafloor after the eruption of the Tagoro submarine volcano off El Hierro Island, Canary Archipelago. Near the summit of the volcanic cone, at about 130 m depth, we found massive mats of long, white filaments that we named Venus's hair. Microscopic and molecular analyses revealed that these filaments are made of bacterial trichomes enveloped within a sheath and colonized by epibiotic bacteria. Metagenomic analyses of the filaments identified a new genus and species of the order Thiotrichales, Thiolava veneris. Venus's hair shows an unprecedented array of metabolic pathways, spanning from the exploitation of organic and inorganic carbon released by volcanic degassing to the uptake of sulfur and nitrogen compounds. This unique metabolic plasticity provides key competitive advantages for the colonization of the new habitat created by the submarine eruption. A specialized and highly diverse food web thrives on the complex three-dimensional habitat formed by these microorganisms, providing evidence that Venus's hair can drive the restart of biological systems after submarine volcanic eruptions.

  1. Impact of major volcanic eruptions on stratospheric water vapour

    Directory of Open Access Journals (Sweden)

    M. Löffler

    2016-05-01

    Full Text Available 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.

  2. Prominence Bubble Shear Flows and the Coupled Kelvin-Helmholtz — Rayleigh-Taylor Instability

    Science.gov (United States)

    Berger, Thomas; Hillier, Andrew

    2017-08-01

    Prominence bubbles are large arched structures that rise from below into quiescent prominences, often growing to heights on the order of 10 Mm before going unstable and generating plume upflows. While there is general agreement that emerging flux below pre-existing prominences causes the structures, there is lack of agreement on the nature of the bubbles and the cause of the instability flows. One hypothesis is that the bubbles contain coronal temperature plasma and rise into the prominence above due to both magnetic and thermal buoyancy, eventually breaking down via a magnetic Rayleigh-Taylor (RT) instability to release hot plasma and magnetic flux and helicity into the overlying coronal flux rope. Another posits that the bubbles are actually just “arcades” in the prominence indicating a magnetic separator line between the bipole and the prominence fields with the observed upflows and downflows caused by reconnection along the separator. We analyze Hinode/SOT, SDO/AIA, and IRIS observations of prominence bubbles, focusing on characteristics of the bubble boundary layers that may discriminate between the two hypotheses. We find speeds on the order of 10 km/s in prominence plasma downflows and lateral shear flows along the bubble boundary. Inflows to the boundary gradually increase the thickness and brightness of the layer until plasma drains from there, apparently around the dome-like bubble domain. In one case, shear flow across the bubble boundary develops Kelvin-Helmholtz (KH) vortices that we use to infer flow speeds in the low-density bubble on the order of 100 km/sec. IRIS spectra indicate that plasma flows on the bubble boundary at transition region temperatures achieve Doppler speeds on the order of 50 km/s, consistent with this inference. Combined magnetic KH-RT instability analysis leads to flux density estimates of 10 G with a field angle of 30° to the prominence, consistent with vector magnetic field measurements. In contrast, we find no evidence

  3. A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Hillier, A. [Kwasan and Hida Observatories, Kyoto University, Kyoto 607-8471 (Japan); Morton, R. J. [Mathematics and Information Science, Northumbria University, Pandon Building, Camden Street, Newcastle upon Tyne NE1 8ST (United Kingdom); Erdélyi, R., E-mail: andrew@kwasan.kyoto-u.ac.jp [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom)

    2013-12-20

    The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s{sup –1}. The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency.

  4. A STATISTICAL STUDY OF TRANSVERSE OSCILLATIONS IN A QUIESCENT PROMINENCE

    International Nuclear Information System (INIS)

    Hillier, A.; Morton, R. J.; Erdélyi, R.

    2013-01-01

    The launch of the Hinode satellite has allowed for seeing-free observations at high-resolution and high-cadence making it well suited to study the dynamics of quiescent prominences. In recent years it has become clear that quiescent prominences support small-amplitude transverse oscillations, however, sample sizes are usually too small for general conclusions to be drawn. We remedy this by providing a statistical study of transverse oscillations in vertical prominence threads. Over a 4 hr period of observations it was possible to measure the properties of 3436 waves, finding periods from 50 to 6000 s with typical velocity amplitudes ranging between 0.2 and 23 km s –1 . The large number of observed waves allows the determination of the frequency dependence of the wave properties and derivation of the velocity power spectrum for the transverse waves. For frequencies less than 7 mHz, the frequency dependence of the velocity power is consistent with the velocity power spectra generated from observations of the horizontal motions of magnetic elements in the photosphere, suggesting that the prominence transverse waves are driven by photospheric motions. However, at higher frequencies the two distributions significantly diverge, with relatively more power found at higher frequencies in the prominence oscillations. These results highlight that waves over a large frequency range are ubiquitous in prominences, and that a significant amount of the wave energy is found at higher frequency

  5. Volcanic Eruptions and Climate: Outstanding Research Issues

    Science.gov (United States)

    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

  6. Ozone depletion following future volcanic eruptions

    Science.gov (United States)

    Eric Klobas, J.; Wilmouth, David M.; Weisenstein, Debra K.; Anderson, James G.; Salawitch, Ross J.

    2017-07-01

    While explosive volcanic eruptions cause ozone loss in the current atmosphere due to an enhancement in the availability of reactive chlorine following the stratospheric injection of sulfur, future eruptions are expected to increase total column ozone as halogen loading approaches preindustrial levels. The timing of this shift in the impact of major volcanic eruptions on the thickness of the ozone layer is poorly known. Modeling four possible climate futures, we show that scenarios with the smallest increase in greenhouse gas concentrations lead to the greatest risk to ozone from heterogeneous chemical processing following future eruptions. We also show that the presence in the stratosphere of bromine from natural, very short-lived biogenic compounds is critically important for determining whether future eruptions will lead to ozone depletion. If volcanic eruptions inject hydrogen halides into the stratosphere, an effect not considered in current ozone assessments, potentially profound reductions in column ozone would result.

  7. Flux Cancellation Leading to CME Filament Eruptions

    Science.gov (United States)

    Popescu, Roxana M.; Panesar, Navdeep K.; Sterling, Alphonse C.; Moore, Ronald L.

    2016-01-01

    Solar filaments are strands of relatively cool, dense plasma magnetically suspended in the lower density hotter solar corona. They trace magnetic polarity inversion lines (PILs) in the photosphere below, and are supported against gravity at heights of up to approx.100 Mm above the chromosphere by the magnetic field in and around them. This field erupts when it is rendered unstable, often by magnetic flux cancellation or emergence at or near the PIL. We have studied the evolution of photospheric magnetic flux leading to ten observed filament eruptions. Specifically, we look for gradual magnetic changes in the neighborhood of the PIL prior to and during eruption. We use Extreme Ultraviolet (EUV) images from the Atmospheric Imaging Assembly (AIA), and magnetograms from the Helioseismic and Magnetic Imager (HMI), both on board the Solar Dynamics Observatory (SDO), to study filament eruptions and their photospheric magnetic fields. We examine whether flux cancellation or/and emergence leads to filament eruptions. We find that continuous flux cancellation was present at the PIL for many hours prior to each eruption. We present two CME-producing eruptions in detail and find the following: (a) the pre-eruption filament-holding core field is highly sheared and appears in the shape of a sigmoid above the PIL; (b) at the start of the eruption the opposite arms of the sigmoid reconnect in the middle above the site of (tether-cutting) flux cancellation at the PIL; (c) the filaments first show a slow-rise, followed by a fast-rise as they erupt. We conclude that these two filament eruptions result from flux cancellation in the middle of the sheared field, and thereafter evolve in agreement with the standard model for a CME/flare filament eruption from a closed bipolar magnetic field [flux cancellation (van Ballegooijen and Martens 1989 and Moore and Roumelrotis 1992) and runaway tether-cutting (Moore et. al 2001)].

  8. Hot prominence detected in the core of a coronal mass ejection. II. Analysis of the C III line detected by SOHO/UVCS

    Science.gov (United States)

    Jejčič, S.; Susino, R.; Heinzel, P.; Dzifčáková, E.; Bemporad, A.; Anzer, U.

    2017-11-01

    Context. We study the physics of erupting prominences in the core of coronal mass ejections (CMEs) and present a continuation of a previous analysis. Aims: We determine the kinetic temperature and microturbulent velocity of an erupting prominence embedded in the core of a CME that occurred on August 2, 2000 using the Ultraviolet Coronagraph and Spectrometer observations (UVCS) on board the Solar and Heliospheric Observatory (SOHO) simultaneously in the hydrogen Lα and C III lines. We develop the non-LTE (departures from the local thermodynamic equilibrium - LTE) spectral diagnostics based on Lα and Lβ measured integrated intensities to derive other physical quantities of the hot erupting prominence. Based on this, we synthesize the C III line intensity to compare it with observations. Methods: Our method is based on non-LTE modeling of eruptive prominences. We used a general non-LTE radiative-transfer code only for optically thin prominence points because optically thick points do not allow the direct determination of the kinetic temperature and microturbulence from the line profiles. The input parameters of the code were the kinetic temperature and microturbulent velocity derived from the Lα and C III line widths, as well as the integrated intensity of the Lα and Lβ lines. The code runs in three loops to compute the radial flow velocity, electron density, and effective thickness as the best fit to the Lα and Lβ integrated intensities within the accuracy defined by the absolute radiometric calibration of UVCS data. Results: We analyzed 39 observational points along the whole erupting prominence because for these points we found a solution for the kinetic temperature and microturbulent velocity. For these points we ran the non-LTE code to determine best-fit models. All models with τ0(Lα) ≤ 0.3 and τ0(C III) ≤ 0.3 were analyzed further, for which we computed the integrated intensity of the C III line using a two-level atom. The best agreement between

  9. Erupted Compound Odontomas: A Case Report

    Directory of Open Access Journals (Sweden)

    Avinash Tejasvi M.L.

    2011-03-01

    Full Text Available The tumors in which odontogenic differentiation is fully expressed are the odontomas. Odontomas are considered as hamartomas rather than a true neoplasm. These tumors are composed of enamel, dentine, cementum and pulp tissue. It is most commonly associated with the eruption of the teeth. They are usually discovered on routine radiographic examination. In exceptional cases, the odontoma erupts in to the mouth. Nine cases of erupted compound odontomas are reported in the English literature, and the present paper reports another case of an erupted compound odontoma in a 22-year-old female patient.

  10. Winter warming from large volcanic eruptions

    Science.gov (United States)

    Robock, Alan; Mao, Jianping

    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.

  11. DYNAMICS OF A SOLAR PROMINENCE TORNADO OBSERVED BY SDO/AIA ON 2012 NOVEMBER 7–8

    Energy Technology Data Exchange (ETDEWEB)

    Mghebrishvili, Irakli; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Ramishvili, Giorgi [Abastumani Astrophysical Observatory at Ilia State University, University St. 2, Tbilisi, Georgia (United States); Shergelashvili, Bidzina [Space Research Institute, Austrian Academy of Sciences, Schmiedlstrasse 6, A-8042 Graz (Austria); Veronig, Astrid [IGAM-Kanzelhöhe Observatory, Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz (Austria); Poedts, Stefaan, E-mail: teimuraz.zaqarashvili@oeaw.ac.at [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, B-3001 Leuven (Belgium)

    2015-09-10

    We study the detailed dynamics of a solar prominence tornado using time series of 171, 304, 193, and 211 Å spectral lines obtained by the Solar Dynamics Observatory/Atmospheric Imaging Assembly during 2012 November 7–8. The tornado first appeared at 08:00 UT, November 07, near the surface, gradually rose upwards with the mean speed of ∼1.5 km s{sup −1} and persisted over 30 hr. Time–distance plots show two patterns of quasi-periodic transverse displacements of the tornado axis with periods of 40 and 50 minutes at different phases of the tornado evolution. The first pattern occurred during the rising phase and can be explained by the upward motion of the twisted tornado. The second pattern occurred during the later stage of evolution when the tornado already stopped rising and could be caused either by MHD kink waves in the tornado or by the rotation of two tornado threads around a common axis. The later hypothesis is supported by the fact that the tornado sometimes showed a double structure during the quasi-periodic phase. 211 and 193 Å spectral lines show a coronal cavity above the prominence/tornado, which started expansion at ∼13:00 UT and continuously rose above the solar limb. The tornado finally became unstable and erupted together with the corresponding prominence as coronal mass ejection (CME) at 15:00 UT, November 08. The final stage of the evolution of the cavity and the tornado-related prominence resembles the magnetic breakout model. On the other hand, the kink instability may destabilize the twisted tornado, and consequently prominence tornadoes can be used as precursors for CMEs.

  12. Critical review of a new volcanic eruption chronology

    Science.gov (United States)

    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.

  13. Multiple dendrochronological responses to the eruption of Cinder Cone, Lassen Volcanic National Park, California

    Science.gov (United States)

    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.

  14. Precursory activity of the 161 ka Kos Plateau Tuff eruption, Aegean Sea (Greece)

    Science.gov (United States)

    Piper, David J. W.; Pe-Piper, Georgia; Lefort, Darren

    2010-08-01

    The Kos Plateau Tuff (KPT) eruption of 161 ka was the largest explosive Quaternary eruption in the eastern Mediterranean. We have discovered an uplifted beach deposit of abraded pumice cobbles, directly overlain by the KPT. The pumice cobbles resemble pumice from the KPT in petrography and composition and differ from Plio-Pleistocene rhyolites on the nearby Kefalos Peninsula. The pumice contains enclaves of basaltic andesite showing chilled lobate margins, suggesting co-existence of two magmas. The deposit provides evidence that the precursory phase of the KPT eruption produced pumice rafts, and defines the paleoshoreline for the KPT, which elsewhere was deposited on land. The beach deposit has been uplifted about 120 m since the KPT eruption, whereas the present marine area south of Kos has subsided several hundred metres, as a result of regional neotectonics. The basaltic andesite is more primitive than other mafic rocks known from the Kos-Nisyros volcanic centre and contains phenocrysts of Fo89 olivine, bytownite, enstatite and diopside. Groundmass amphibole suggests availability of water in the final stages of magma evolution. Geochemical and mineralogical variation in the mafic products of the KPT eruption indicate that fractionation of basaltic magma in a base-of-crust magma chamber was followed by mixing with rhyolitic magma during eruption. Low eruption rates during the precursory activity may have minimised the extent of mixing and preserved the end-member magma types.

  15. ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

    International Nuclear Information System (INIS)

    Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M.; Beck, C.; Rodríguez, J. de la Cruz

    2016-01-01

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

  16. ON THE MAGNETISM AND DYNAMICS OF PROMINENCE LEGS HOSTING TORNADOES

    Energy Technology Data Exchange (ETDEWEB)

    Martínez González, M. J.; Ramos, A. Asensio; Arregui, I.; Collados, M. [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Beck, C. [National Solar Observatory, Sacramento Peak P.O. Box 62, Sunspot, NM 88349 (United States); Rodríguez, J. de la Cruz [Institute for Solar Physics, Department of Astronomy, Stockholm University, Albanova University Center, SE-10691 Stockholm (Sweden)

    2016-07-10

    Solar tornadoes are dark vertical filamentary structures observed in the extreme ultraviolet associated with prominence legs and filament barbs. Their true nature and relationship to prominences requires an understanding of their magnetic structure and dynamic properties. Recently, a controversy has arisen: is the magnetic field organized forming vertical, helical structures or is it dominantly horizontal? And concerning their dynamics, are tornadoes really rotating or is it just a visual illusion? Here we analyze four consecutive spectro-polarimetric scans of a prominence hosting tornadoes on its legs, which helps us shed some light on their magnetic and dynamical properties. We show that the magnetic field is very smooth in all the prominence, which is probably an intrinsic property of the coronal field. The prominence legs have vertical helical fields that show slow temporal variation that is probably related to the motion of the fibrils. Concerning the dynamics, we argue that (1) if rotation exists, it is intermittent, lasting no more than one hour, and (2) the observed velocity pattern is also consistent with an oscillatory velocity pattern (waves).

  17. Solar Tornado Prominences: Plasma Motions Along Filament Barbs

    Science.gov (United States)

    Panasenco, Olga; Velli, Marco; Martin, Sara F.; Rappazzo, Franco

    2013-03-01

    Recent high-resolution observations from the Solar Dynamic Observatory (SDO) have reawakened interest in the old and fascinating phenomenon of solar tornado prominences. This class of prominences was first introduced by E. Pettit in 1932, who studied them over many years up to 1950. High resolution and high cadence multi-wavelength data obtained by SDO reveal that the tornado-like properties of these prominences are mainly an illusion due to projection effects. We show that counterstreaming plasma motions with projected velocities up to +/- 45 km/sec along the prominence spine and barbs create a tornado-like impression when viewed at the limb. We demonstrate that barbs are often rooted at the intersection between 4-5 supergranular cells. We discuss the observed oscillations along the vertical parts of barbs and whether they may be related to vortex flows coming from the convection downdrafts at the intersection of supergranules (and possibly smaller convective cells) in the photosphere and their entrained magnetic field. The unwinding of magnetic threads near the photosphere via reconnection might be a source of the waves which are observed as oscillations in prominence barbs.

  18. Long-Term Volumetric Eruption Rates and Magma Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Scott M. White Dept. Geological Sciences University of South Carolina Columbia, SC 29208; Joy A. Crisp Jet Propulsion Laboratory, California Institute of Technology Pasadena, CA 91109; Frank J. Spera Dept. Earth Science University of California, Santa Barbara Santa Barbara, CA 93106

    2005-01-01

    A global compilation of 170 time-averaged volumetric volcanic output rates (Qe) is evaluated in terms of composition and petrotectonic setting to advance the understanding of long-term rates of magma generation and eruption on Earth. Repose periods between successive eruptions at a given site and intrusive:extrusive ratios were compiled for selected volcanic centers where long-term (>104 years) data were available. More silicic compositions, rhyolites and andesites, have a more limited range of eruption rates than basalts. Even when high Qe values contributed by flood basalts (9 ± 2 Å~ 10-1 km3/yr) are removed, there is a trend in decreasing average Qe with lava composition from basaltic eruptions (2.6 ± 1.0 Å~ 10-2 km3/yr) to andesites (2.3 ± 0.8 Å~ 10-3 km3/yr) and rhyolites (4.0 ± 1.4 Å~ 10-3 km3/yr). This trend is also seen in the difference between oceanic and continental settings, as eruptions on oceanic crust tend to be predominately basaltic. All of the volcanoes occurring in oceanic settings fail to have statistically different mean Qe and have an overall average of 2.8 ± 0.4 Å~ 10-2 km3/yr, excluding flood basalts. Likewise, all of the volcanoes on continental crust also fail to have statistically different mean Qe and have an overall average of 4.4 ± 0.8 Å~ 10-3 km3/yr. Flood basalts also form a distinctive class with an average Qe nearly two orders of magnitude higher than any other class. However, we have found no systematic evidence linking increased intrusive:extrusive ratios with lower volcanic rates. A simple heat balance analysis suggests that the preponderance of volcanic systems must be open magmatic systems with respect to heat and matter transport in order to maintain eruptible magma at shallow depth throughout the observed lifetime of the volcano. The empirical upper limit of Å`10-2 km3/yr for magma eruption rate in systems with relatively high intrusive:extrusive ratios may be a consequence of the fundamental parameters

  19. SANTORINI BEFORE THE MINOAN ERUPTION

    DEFF Research Database (Denmark)

    Friedrich, Walter L.; Sørensen, Annette Højen; Katsipis, Samson

    2014-01-01

    Conclusions Several detailed geological observations in the landscape of Santorini enable us to claim that the two harbour towns were located on the inner side of the caldera wall on the island of Thera prior to the Minoan Eruption. This hypothesis is in agreement with the excavation sites of Bal...... that the fresco shows a joyful scene where the inhabitants of Bronze Age Santorini celebrate the seasonal change in connection with the arrival of life-giving rainwater either at the beginning of spring or at the end of the sailing season in autumn (Pl. CXLVIIc)....

  20. The 2011 submarine volcanic eruption of El Hierro Island (Canary Islands, Spain)

    Science.gov (United States)

    López, C.; Blanco, M. J.

    2012-04-01

    On 10 October 2011 a submarine volcanic eruption began 2 km SW of La Restinga village in the South coast of El Hierro Island (Spain). It became the first submarine eruption reported in 500 years of historical record in the Canary Islands. The eruption took place after three months of intensive seismic activity and ground deformation. The first signal evidencing the eruption was a harmonic tremor signal, located somewhere in the South sector of El Hierro Island and registered in every seismic station on the island. On the following day, the tremoŕs amplitude increased up enough to be felt by the residents of La Restinga. The first visual evidence of the eruption was observed during the afternoon of 12 October, a large light-green coloured area on the sea surface, 2 km to the SW of La Restinga. Three days later, steaming lava fragments were observed floating on the sea, in the area where the vent was supposed to be located. These fragments had a bomb-like shape and their sizes ranged between 10 and 40 cm long. They were bicoloured, a black outer part with a basaltic composition, and a white inner part, highly vesiculated and rich in silica content (>60%). This type of fragments was only observed during the first days of the eruption. Within the next two months further emission episodes have been observed with turbulent water, foam rings and large bubbles on the sea surface. On the 27th of November new lava fragments were observed while floating and degassing on the sea surface. Most of them were "lava balloons" or hollow fragments of lavas, with sizes between 30 and 200 cm, and highly vesiculated outer crust of basaltic-basanitic and sideromelane composition. The emission of these products continues intermitently up to date (January 2012) During the eruption, the GPS monitoring network detected episodes of inflation-deflation and a maximum vertical deformation of 4 cm. The horizontal deformation, which had reached up to 5 cm before the eruption, remains stable. The

  1. Reconnection–Condensation Model for Solar Prominence Formation

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Takafumi [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601 (Japan); Yokoyama, Takaaki, E-mail: kaneko@isee.nagoya-u.ac.jp [Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2017-08-10

    We propose a reconnection–condensation model in which topological change in a coronal magnetic field via reconnection triggers radiative condensation, thereby resulting in prominence formation. Previous observational studies have suggested that reconnection at a polarity inversion line of a coronal arcade field creates a flux rope that can sustain a prominence; however, they did not explain the origin of cool dense plasmas of prominences. Using three-dimensional magnetohydrodynamic simulations, including anisotropic nonlinear thermal conduction and optically thin radiative cooling, we demonstrate that reconnection can lead not only to flux rope formation but also to radiative condensation under a certain condition. In our model, this condition is described by the Field length, which is defined as the scale length for thermal balance between radiative cooling and thermal conduction. This critical condition depends weakly on the artificial background heating. The extreme ultraviolet emissions synthesized with our simulation results have good agreement with observational signatures reported in previous studies.

  2. From Wilhelm von Humboldt to Hitler-are prominent people more prone to have Parkinson's disease?

    Science.gov (United States)

    Horowski; Horowski; Calne; Calne

    2000-10-01

    We describe Parkinsonism in prominent people, where Wilhelm von Humboldt and Adolf Hitler provide just two spectacular, opposing examples. In both of them, there is little if any evidence that the disease did influence their life ambitions, methods of achieving them or cognitive function in general. Thus, Hitler's Parkinsonism should remain a 'footnote' to history, and historians should acknowledge that in his last years, his trembling, his curbed posture, his slow walking, mask-like face and low voice did not indicate remorse, fear or depression as a consequence of his crimes, but were mere expressions of his disease which, until the end, had no impact on his intellectual skills and methods. The apparently higher incidence of Parkinsonism in prominent people may be just due to their higher visibility, or a consequence of disease-related personality traits (e.g. ambition, perfectionism, rigidity) which may contribute to becoming, e.g., a prominent authoritarian person. Perhaps even some early behaviour pattern (such as repressed emotions or acting in public-which could even increase the risk of some infection) contributes to a greater vulnerability for developing Parkinsonism. Further studying other prominent cases might lead us to better understanding of risk factors and the expression of early Parkinsonism.

  3. The 2014 eruptions of Pavlof Volcano, Alaska

    Science.gov (United States)

    Waythomas, Christopher F.; Haney, Matthew M.; Wallace, Kristi; Cameron, Cheryl E.; Schneider, David J.

    2017-12-22

    Pavlof Volcano is one of the most frequently active volcanoes in the Aleutian Island arc, having erupted more than 40 times since observations were first recorded in the early 1800s . The volcano is located on the Alaska Peninsula (lat 55.4173° N, long 161.8937° W), near Izembek National Wildlife Refuge. The towns and villages closest to the volcano are Cold Bay, Nelson Lagoon, Sand Point, and King Cove, which are all within 90 kilometers (km) of the volcano (fig. 1). Pavlof is a symmetrically shaped stratocone that is 2,518 meters (m) high, and has about 2,300 m of relief. The volcano supports a cover of glacial ice and perennial snow roughly 2 to 4 cubic kilometers (km3) in volume, which is mantled by variable amounts of tephra fall, rockfall debris, and pyroclastic-flow deposits produced during historical eruptions. Typical Pavlof eruptions are characterized by moderate amounts of ash emission, lava fountaining, spatter-fed lava flows, explosions, and the accumulation of unstable mounds of spatter on the upper flanks of the volcano. The accumulation and subsequent collapse of spatter piles on the upper flanks of the volcano creates hot granular avalanches, which erode and melt snow and ice, and thereby generate watery debris-flow and hyperconcentrated-flow lahars. Seismic instruments were first installed on Pavlof Volcano in the early 1970s, and since then eruptive episodes have been better characterized and specific processes have been documented with greater certainty. The application of remote sensing techniques, including the use of infrasound data, has also aided the study of more recent eruptions. Although Pavlof Volcano is located in a remote part of Alaska, it is visible from Cold Bay, Sand Point, and Nelson Lagoon, making distal observations of eruptive activity possible, weather permitting. A busy air-travel corridor that is utilized by a numerous transcontinental and regional air carriers passes near Pavlof Volcano. The frequency of air travel

  4. Static current-sheet models of quiescent prominences

    Science.gov (United States)

    Wu, F.; Low, B. C.

    1986-12-01

    A particular class of theoretical models idealize the prominence to be a discrete flat electric-current sheet suspended vertically in a potential magnetic field. The weight of the prominence is supported by the Lorentz force in the current sheet. These models can be extended to have curved electric-current sheets and to vary three-dimensionally. The equation for force balance is 1 over 4 pi (del times B) times Bdel p- p9 z=zero. Using Cartesian coordinates we take, for simplicity, a uniform gravity with constant acceleration g in the direction -z. If we are interested not in the detailed internal structure of the prominence, but in the global magnetic configuration around the prominence, we may take prominence plasma to be cold. Consideration is given to how such equilibrium states can be constructed. To simplify the mathematical problem, suppose there is no electric current in the atmosphere except for the discrete currents in the cold prominence sheet. Let us take the plane z =0 to be the base of the atmosphere and restrict our attention to the domain z greater than 0. The task we have is to solve for a magnetic field which is everywhere potential except on some free surface S, subject to suit able to boundary conditions. The surface S is determined by requiring that it possesses a discrete electric current density such that the Lorentz force on it is everywhere vertically upward to balance the weight of the material m(S). Since the magnetic field is potential in the external atmosphere, the latter is decoupled from the magnetic field and its plane parallel hydrostatic pressure and density can be prescribed.

  5. Solar Prominence Modelling and Plasma Diagnostics at ALMA Wavelengths

    Science.gov (United States)

    Rodger, Andrew; Labrosse, Nicolas

    2017-09-01

    Our aim is to test potential solar prominence plasma diagnostics as obtained with the new solar capability of the Atacama Large Millimeter/submillimeter Array (ALMA). We investigate the thermal and plasma diagnostic potential of ALMA for solar prominences through the computation of brightness temperatures at ALMA wavelengths. The brightness temperature, for a chosen line of sight, is calculated using the densities of electrons, hydrogen, and helium obtained from a radiative transfer code under non-local thermodynamic equilibrium (non-LTE) conditions, as well as the input internal parameters of the prominence model in consideration. Two distinct sets of prominence models were used: isothermal-isobaric fine-structure threads, and large-scale structures with radially increasing temperature distributions representing the prominence-to-corona transition region. We compute brightness temperatures over the range of wavelengths in which ALMA is capable of observing (0.32 - 9.6 mm), however, we particularly focus on the bands available to solar observers in ALMA cycles 4 and 5, namely 2.6 - 3.6 mm (Band 3) and 1.1 - 1.4 mm (Band 6). We show how the computed brightness temperatures and optical thicknesses in our models vary with the plasma parameters (temperature and pressure) and the wavelength of observation. We then study how ALMA observables such as the ratio of brightness temperatures at two frequencies can be used to estimate the optical thickness and the emission measure for isothermal and non-isothermal prominences. From this study we conclude that for both sets of models, ALMA presents a strong thermal diagnostic capability, provided that the interpretation of observations is supported by the use of non-LTE simulation results.

  6. Prominent crista terminalis mimicking a right atrial mass: case report

    Directory of Open Access Journals (Sweden)

    Lange Peter

    2010-10-01

    Full Text Available Abstract The crista terminalis is a normal anatomical structure within the right atrium that is not normally visualised in the standard views obtained while performing a transthoracic echocardiogram. In this case report, transthoracic echocardiography suggested the presence of a right atrial mass in a patient with end stage renal disease. However, subsequent transesophageal echocardiography revealed that the right atrial mass was actually a thick muscular bridge in the right atrium consistent with a prominent crista terminalis. An understanding of the anatomy and the echocardiographic appearance of a prominent crista terminalis will minimize the misdiagnosis of this structure avoiding unnecessary expensive additional tests.

  7. Global Significant Volcanic Eruptions Database, 4360 BC to present

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Significant Volcanic Eruptions Database is a global listing of over 600 eruptions from 4360 BC to the present. A significant eruption is classified as one that...

  8. Palifermin-associated papular eruption.

    Science.gov (United States)

    King, Brett; Knopp, Eleanor; Galan, Anjela; Nuovo, Gerard; Tigelaar, Robert; McNiff, Jennifer

    2009-02-01

    Palifermin is a recombinant human keratinocyte growth factor that is used to reduce the duration and severity of oral mucositis in patients undergoing hematopoietic stem cell transplantation after myelotoxic therapy. Cutaneous adverse reactions associated with keratinocyte growth factor are reported to be rash, pruritus, and erythema. After receiving palifermin following autologous hematopoietic stem cell transplantation and treatment with melphalan, a patient developed erythema and lichenoid papules that were distributed primarily in intertriginous areas. A biopsy specimen of the papules showed a striking resemblance to verrucae, but in situ hybridization studies were negative for human papillomavirus. Immunohistochemical staining with antibodies to Ki-67 and cytokeratin 5/6 showed increased keratinocyte proliferation in lesional skin. After treatment with palifermin, a papular eruption clinically resembling lichen planus or plane warts, with histologic features of verruca plana, and intertriginous erythema may occur. In this case, neither eruption required treatment, and spontaneous resolution was observed over days to weeks. Histopathologic staining patterns of Ki-67 and cytokeratin 5/6 may be useful in identifying adverse reactions to palifermin therapy.

  9. Magnetic Braids in Eruptions of a Spiral Structure in the Solar Atmosphere

    Science.gov (United States)

    Huang, Zhenghua; Xia, Lidong; Nelson, Chris J.; Liu, Jiajia; Wiegelmann, Thomas; Tian, Hui; Klimchuk, James A.; Chen, Yao; Li, Bo

    2018-02-01

    We report on high-resolution imaging and spectral observations of eruptions of a spiral structure in the transition region, which were taken with the Interface Region Imaging Spectrograph, and the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO). The eruption coincided with the appearance of two series of jets, with velocities comparable to the Alfvén speeds in their footpoints. Several pieces of evidence of magnetic braiding in the eruption are revealed, including localized bright knots, multiple well-separated jet threads, transition region explosive events, and the fact that all three of these are falling into the same locations within the eruptive structures. Through analysis of the extrapolated 3D magnetic field in the region, we found that the eruptive spiral structure corresponded well to locations of twisted magnetic flux tubes with varying curl values along their lengths. The eruption occurred where strong parallel currents, high squashing factors, and large twist numbers were obtained. The electron number density of the eruptive structure is found to be ∼3 × 1012 cm‑3, indicating that a significant amount of mass could be pumped into the corona by the jets. Following the eruption, the extrapolations revealed a set of seemingly relaxed loops, which were visible in the AIA 94 Å channel, indicating temperatures of around 6.3 MK. With these observations, we suggest that magnetic braiding could be part of the mechanisms explaining the formation of solar eruption and the mass and energy supplement to the corona.

  10. Probabilistic tephra hazard maps for the Neapolitan area: Quantitative volcanological study of Campi Flegrei eruptions

    Science.gov (United States)

    Mastrolorenzo, G.; Pappalardo, L.; Troise, C.; Panizza, A.; de Natale, G.

    2008-07-01

    Tephra fall is a relevant hazard of Campi Flegrei caldera (Southern Italy), due to the high vulnerability of Naples metropolitan area to such an event. Here, tephra derive from magmatic as well as phreatomagmatic activity. On the basis of both new and literature data on known, past eruptions (Volcanic Explosivity Index (VEI), grain size parameters, velocity at the vent, column heights and erupted mass), and factors controlling tephra dispersion (wind velocity and direction), 2D numerical simulations of fallout dispersion and deposition have been performed for a large number of case events. A bayesian inversion has been applied to retrieve the best values of critical parameters (e.g., vertical mass distribution, diffusion coefficients, velocity at the vent), not directly inferable by volcanological study. Simulations are run in parallel on multiple processors to allow a fully probabilistic analysis, on a very large catalogue preserving the statistical proprieties of past eruptive history. Using simulation results, hazard maps have been computed for different scenarios: upper limit scenario (worst-expected scenario), eruption-range scenario, and whole-eruption scenario. Results indicate that although high hazard characterizes the Campi Flegrei caldera, the territory to the east of the caldera center, including the whole district of Naples, is exposed to high hazard values due to the dominant westerly winds. Consistently with the stratigraphic evidence of nature of past eruptions, our numerical simulations reveal that even in the case of a subplinian eruption (VEI = 3), Naples is exposed to tephra fall thicknesses of some decimeters, thereby exceeding the critical limit for roof collapse. Because of the total number of people living in Campi Flegrei and the city of Naples (ca. two million of inhabitants), the tephra fallout risk related to a plinian eruption of Campi Flegrei largely matches or exceeds the risk related to a similar eruption at Vesuvius.

  11. Orientation of the eruption fissures controlled by a shallow magma chamber in Miyakejima

    Directory of Open Access Journals (Sweden)

    Nobuo Geshi

    2016-11-01

    Full Text Available Orientation of the eruption fissures and composition of the lavas of the Miyakejima volcano indicate tectonic influence of a shallow magma chamber on the distribution of eruption fissures. We examined the distributions and magmatic compositions of 23 fissures that formed within the last 2800 years, based on a field survey and a new dataset of 14C ages. The dominant orientation of the eruption fissures in the central portion of the volcano was found to be NE-SW, which is perpendicular to the direction of regional maximum horizontal compressive stress (σHmax. Magmas that show evidences of magma mixing between basaltic and andesitic magmas erupted mainly from the eruption fissures with a higher offset angle from the regional σHmax direction. The presence of a shallow dike-shaped magma chamber controls the distribution of the eruption fissures. The injection of basaltic magma into the shallow andesitic magma chamber caused the temporal rise of internal magmatic pressure in the shallow magma chamber. Dikes extending from the andesitic magma chamber intrude along the local compressive stress field which is generated by the internal excess pressure of the andesitic magma chamber. As the result, the eruption fissures trend parallel to the elongation direction of the shallow magma chamber. Injection of basaltic magma into the shallow andesitic magma chamber caused the magma mixing. Some basaltic dikes from the deep-seated magma chamber reach the ground surface without intersection with the andesitic magma chamber. The patterns of the eruption fissures can be modified in the future as was observed in the case of the destruction of the shallow magma chamber during the 2000 AD eruption.

  12. Insights into the Toba Super-Eruption using SEM Analysis of Ash Deposits

    Science.gov (United States)

    Gatti, E.; Achyuthan, H.; Durant, A. J.; Gibbard, P.; Mokhtar, S.; Oppenheimer, C.; Raj, R.; Shridar, A.

    2010-12-01

    The ~74 ka Youngest Toba Tuff (YTT) super-eruption of Toba volcano, Northern Sumatra, was the largest eruption of the Quaternary (magnitude M= 8.8) and injected massive quantities of volcanic gases and ash into the stratosphere. YTT deposits covered at least 40,000,000 km2 of Southeast Asia and are preserved in river valleys across peninsular India and Malaysia, and in deep-sea tephra layers in the Indian Ocean, Bay of Bengal and South China Sea. Initial studies hypothesized the eruption caused immediate and substantial global cooling during the ~ 1 kyr between Dansgaard-Oeschger events 19 and 20 which devastated ecosystems and hominid populations. A more recent review argues against severe post-YTT climatic deterioration and cannot find clear evidence for considerable impacts on ecosystems or bio-diversity. The determination of the eruptive parameters is crucial in this issue to document the eruption and understand the potential impacts from future super-volcanic eruptions. Volcanic ash deposits can offer dramatic insights into key eruptive parameters, including magnitude, duration and plume height. The composition and shape of volcanic ashes can be used to interpret physical properties of an erupting magma and tephra transport, while textural characteristics such as grain roughness and surface vescicularity can provide insights into degassing history, volatile content and explosive activity of the volcano. We present a stratigraphic and sedimentological analysis of YTT deposits in stratified contexts at three localities in India, at two sites in Peninsular Malaysia, and at several localities around Lake Toba and on Samosir Island, Sumatra. These sites offer excellent constraints on the spatial distribution of YTT deposits which can be used to infer dispersal directions of the cloud, and provide insights into environmental controls on preservation of tephra beds. The research aims at a systematic interpretation of the Toba tephra to understand the volcanic

  13. Progressive approach to eruption at Campi Flegrei caldera in southern Italy.

    Science.gov (United States)

    Kilburn, Christopher R J; De Natale, Giuseppe; Carlino, Stefano

    2017-05-15

    Unrest at large calderas rarely ends in eruption, encouraging vulnerable communities to perceive emergency warnings of volcanic activity as false alarms. A classic example is the Campi Flegrei caldera in southern Italy, where three episodes of major uplift since 1950 have raised its central district by about 3 m without an eruption. Individual episodes have conventionally been treated as independent events, so that only data from an ongoing episode are considered pertinent to evaluating eruptive potential. An implicit assumption is that the crust relaxes accumulated stress after each episode. Here we apply a new model of elastic-brittle failure to test the alternative view that successive episodes promote a long-term accumulation of stress in the crust. The results provide the first quantitative evidence that Campi Flegrei is evolving towards conditions more favourable to eruption and identify field tests for predictions on how the caldera will behave during future unrest.

  14. Decade of stratospheric sulfate measurements compared with observations of volcanic eruptions

    International Nuclear Information System (INIS)

    Sedlacek, W.A.; Mroz, E.J.; Lazrus, A.L.; Gandrud, B.W.

    1983-01-01

    Sulfate aerosol concentrations in the stratosphere have been measured for 11 years (1971--1981) using portions of filters collected by the Department of Energy's High Altitude Sampling Program. Data collected seasonally at altitudes between 13 km and 20 km spanning latitudes from 75 0 N to 51 0 S are reported. These data are compared with the reported altitudes of volcanic eruption plumes during the same decade. From this comparison it is concluded that (1) several unreported volcanic eruptions or eruptions to altitudes higher than reported did occur during the decade, (2) the e-fold removal time for sulfate aerosol from the stratosphere following the eruption of Volcan Fuego in 1974 was 11.2 +- 1.2 months, (3) the volcanic contribution to the average stratospheric sulfate concentration over the decade was greater than 50%, and (4) there may be evidence for an anthropogenic contribution to stratospheric sulfate that increases at the rate of 6 to 8% per year

  15. Small volcanic eruptions and the stratospheric sulfate aerosol burden

    Science.gov (United States)

    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

  16. PATTERNS OF FLOWS IN AN INTERMEDIATE PROMINENCE OBSERVED BY HINODE

    International Nuclear Information System (INIS)

    Ahn, Kwangsu; Chae, Jongchul; Cao Wenda; Goode, Philip R.

    2010-01-01

    The investigation of plasma flows in filaments/prominences gives us clues to understanding their magnetic structures. We studied the patterns of flows in an intermediate prominence observed by Hinode/SOT. By examining a time series of Hα images and Ca II H images, we have found horizontal flows in the spine and vertical flows in the barb. Both of these flows have a characteristic speed of 10-20 km s -1 . The horizontal flows displayed counterstreaming. Our detailed investigation revealed that most of the moving fragments in fact reversed direction at the end point of the spine near a footpoint close to the associated active region. These returning flows may be one possible explanation of the well-known counterstreaming flows in prominences. In contrast, we have found vertical flows-downward and upward-in the barb. Most of the horizontal flows in the spine seem to switch into vertical flows when they approach the barb, and vice versa. We propose that the net force resulting from a small deviation from magnetohydrostatic equilibrium, where magnetic fields are predominantly horizontal, may drive these patterns of flow. In the prominence studied here, the supposed magnetohydrostatic configuration is characterized by magnetic field lines sagging with angles of 13 0 and 39 0 in the spine and the barb, respectively.

  17. The Most Prominent Roles of an ESP Teacher

    Science.gov (United States)

    Ghafournia, Narjes; Sabet, Shokoofeh Ahmadian

    2014-01-01

    One prominent feature of many ESP (English for Specific Purposes) courses, which make them rather different from EGP (English for General Purposes) courses, is the presence of adult learners, who are primary workers and secondary learners. As ESP is a highly learner-cantered approach, paying close attention to the multidimensional needs of…

  18. On Lyman-line asymmetries in quiescent prominences

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Heinzel, Petr; Anzer, U.; Schmieder, B.

    2008-01-01

    Roč. 490, č. 1 (2008), s. 307-313 ISSN 0004-6361 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun prominences * radiative transfer * line profiles Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

  19. Unintended exposure in radiotherapy: Identification of prominent causes

    International Nuclear Information System (INIS)

    Boadu, Mary; Rehani, Madan Mohan

    2009-01-01

    Background and purpose: Unintended exposures in radiotherapy are likely to occur when certain conditions that favour such exposures exist. Based on the frequency of occurrence of various causes of 100 events of unintended exposures in radiotherapy as derived from the analysis of published reports, a checklist for assessing the vulnerability of radiotherapy facilities for potential accidents has been prepared. The list presents items to be considered for safety critical assessments of a radiotherapy department for the improvement of patient safety and the entire radiotherapy processes. Materials and methods: The resources used for this paper consist of 100 unintended radiotherapy exposures and were derived from existing published reports. The analysis was performed by forming two templates: one consisting of 10 initiating events and another of 35 contributing factors. Results: Four most prominent initiating events were identified and together accounted for about 70% of all the unintended exposure events. Ten most prominent contributing factors were also identified and together accounted for about 70% of all the radiotherapy unintended exposure events covered under this study. Conclusion: With this knowledge of high frequency of occurrences, the identified four prominent initiating events and the 10 most prominent contributing factors must be checked and dealt with as a matter of priority when assessing the safety of a radiotherapy facility. A simple checklist for checking the quality assurance programmes of a radiotherapy department for every aspect of the design and delivery of radiation have been provided.

  20. Further Validation of the Coach Identity Prominence Scale

    Science.gov (United States)

    Pope, J. Paige; Hall, Craig R.

    2014-01-01

    This study was designed to examine select psychometric properties of the Coach Identity Prominence Scale (CIPS), including the reliability, factorial validity, convergent validity, discriminant validity, and predictive validity. Coaches (N = 338) who averaged 37 (SD = 12.27) years of age, had a mean of 13 (SD = 9.90) years of coaching experience,…

  1. Whole genome microarray analysis of chicken embryo facial prominences

    Czech Academy of Sciences Publication Activity Database

    Buchtová, Marcela; Kuo, W. P.; Nimmagadda, S.; Benson, S. L.; Geetha-Loganathan, P.; Logan, C.; Au-Yeung, T.; Chiang, E.; Fu, K.; Richman, J. M.

    2010-01-01

    Roč. 239, - (2010), s. 574-591 ISSN 1058-8388 Institutional research plan: CEZ:AV0Z50450515 Keywords : pharyngeal arch * mandibular arch * maxillary prominence Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.864, year: 2010

  2. Prominence modelling: from observed emission measures to temperature profiles

    Czech Academy of Sciences Publication Activity Database

    Anzer, U.; Heinzel, Petr

    2008-01-01

    Roč. 480, č. 2 (2008), s. 537-542 ISSN 0004-6361 Grant - others:EU(XE) ESA-PECS Project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun * prominences * transition region Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.153, year: 2008

  3. Holdaway's analysis of the nose prominence of an adult Nigerian ...

    African Journals Online (AJOL)

    The nose prominence was assessed using Holdaway's analysis. Twenty radiographs randomly selected, were retraced to assess for errors. Data analysis included descriptive statistics, Student's t‑tests and analysis of variance using the Statistical Package for Social Sciences. Results: The mean value recorded for the nose ...

  4. Cylindrical prominences and the magnetic influence of the photospheric boundary

    International Nuclear Information System (INIS)

    Lerche, I.; Chicago Univ., IL; Low, B.C.

    1980-01-01

    We construct exact, non-linear, solutions for an horizontal, cylindrical, current-carrying, prominence supported against solar gravity by the action of a Lorentz force. The solutions incorporate the photosphere boundary condition, proposed by van Tend and Kuperus (1978), and analyzed by them for line filaments. Our solutions have finite radius for the prominence material and, as well as satisfying the equations of magnetostatic equilibrium, they allow for the continuity of gas pressure, and of the normal and tangential components of magnetic field across the circular prominence boundary. We show that an infinity of solutions is possible and we illustrate the basic behavior by investigation of a special case. We also give a prescription for constructing equilibrium fields for any horizontal prominence with arbitrary cross-section and with an arbitrary external magnetic field. The prescription is ideally suited for numerical codes and we suggest that both the equilibrium of such shapes can easily be accomplished numerically together with their evolutionary history. (orig.)

  5. Lines of MgI Detected in Solar Prominences

    Czech Academy of Sciences Publication Activity Database

    Heinzel, Petr; Kupryakov, Yu. A.; Schwartz, P.

    2016-01-01

    Roč. 40, č. 1 (2016), s. 87-91 ISSN 1845-8319. [Hvar Astrophysical Colloquium /14./. Hvar, 26.09.2016-30.09.2016] Institutional support: RVO:67985815 Keywords : prominences * limb-flare * MgI emession Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  6. Topics and topic prominence in two sign languages

    NARCIS (Netherlands)

    Kimmelman, V.

    2015-01-01

    In this paper we describe topic marking in Russian Sign Language (RSL) and Sign Language of the Netherlands (NGT) and discuss whether these languages should be considered topic prominent. The formal markers of topics in RSL are sentence-initial position, a prosodic break following the topic, and

  7. Multi-Wavelength Eclipse Observations of a Quiescent Prominence

    Czech Academy of Sciences Publication Activity Database

    Jejčič, S.; Heinzel, Petr; Zapiór, M.; Druckmüller, M.; Gunár, Stanislav; Kotrč, Pavel

    2014-01-01

    Roč. 289, č. 7 (2014), s. 2487-2501 ISSN 0038-0938 R&D Projects: GA ČR GAP209/12/0906 Institutional support: RVO:67985815 Keywords : eclipse observations * prominences * quiescent Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.039, year: 2014

  8. Electron densities in quiescent prominences derived from eclipse observations

    Czech Academy of Sciences Publication Activity Database

    Jejčič, S.; Heinzel, Petr

    2009-01-01

    Roč. 254, č. 1 (2009), s. 89-100 ISSN 0038-0938 Grant - others:EU(XE) ESA-PECS project No. 98030 Institutional research plan: CEZ:AV0Z10030501 Keywords : prominences quiescent * eclipse observations * visible spectrum Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.628, year: 2009

  9. An extreme ultraviolet wave associated with a failed eruption observed by the Solar Dynamics Observatory

    Science.gov (United States)

    Zheng, R.; Jiang, Y.; Yang, J.; Bi, Y.; Hong, J.; Yang, B.; Yang, D.

    2012-05-01

    Aims: Taking advantage of the high temporal and spatial resolution of the Solar Dynamics Observatory (SDO) observations, we present an extreme ultraviolet (EUV) wave associated with a failed filament eruption that generated no coronal mass ejection (CME) on 2011 March 1. We aim at understanding the nature and origin of this EUV wave. Methods: Combining the high-quality observations in the photosphere, the chromosphere, and the corona, we studied the characteristics of the wave and its relations to the associated eruption. Results: The event occurred at an ephemeral region near a small active region. The continuous magnetic flux cancelation in the ephemeral region produced pre-eruption brightenings and two EUV jets, and excited the filament eruption, accompanying it with a microflare. After the eruption, the filament material appeared far from the eruption center, and the ambient loops seemed to be intact. It was evident that the filament eruption had failed and was not associated with a CME. The wave happened just after the north jet arrived, and apparently emanated ahead of the north jet, far from the eruption center. The wave propagated at nearly constant velocities in the range of 260-350 km s-1, with a slight negative acceleration in the last phase. Remarkably, the wave continued to propagate, and a loop in its passage was intact when wave and loop met. Conclusions: Our analysis confirms that the EUV wave is a true wave, which we interpret as a fast-mode wave. In addition, the close temporal and spatial relationship between the wave and the jet provides evidence that the wave was likely triggered by the jet when the CME failed to happen. Three movies are available in electronic form at http://www.aanda.org

  10. Thermal vesiculation during volcanic eruptions.

    Science.gov (United States)

    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

  11. RADIO DIAGNOSTICS OF ELECTRON ACCELERATION SITES DURING THE ERUPTION OF A FLUX ROPE IN THE SOLAR CORONA

    Energy Technology Data Exchange (ETDEWEB)

    Carley, Eoin P.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Vilmer, Nicole, E-mail: eoin.carley@obspm.fr [LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, F-92195 Meudon (France)

    2016-12-10

    Electron acceleration in the solar corona is often associated with flares and the eruption of twisted magnetic structures known as flux ropes. However, the locations and mechanisms of such particle acceleration during the flare and eruption are still subject to much investigation. Observing the exact sites of particle acceleration can help confirm how the flare and eruption are initiated and how they evolve. Here we use the Atmospheric Imaging Assembly to analyze a flare and erupting flux rope on 2014 April 18, while observations from the Nançay Radio Astronomy Facility allow us to diagnose the sites of electron acceleration during the eruption. Our analysis shows evidence of a pre-formed flux rope that slowly rises and becomes destabilized at the time of a C-class flare, plasma jet, and the escape of ≳75 keV electrons from the rope center into the corona. As the eruption proceeds, continued acceleration of electrons with energies of ∼5 keV occurs above the flux rope for a period over 5 minutes. At the flare peak, one site of electron acceleration is located close to the flare site, while another is driven by the erupting flux rope into the corona at speeds of up to 400 km s{sup −1}. Energetic electrons then fill the erupting volume, eventually allowing the flux rope legs to be clearly imaged from radio sources at 150–445 MHz. Following the analysis of Joshi et al. (2015), we conclude that the sites of energetic electrons are consistent with flux rope eruption via a tether cutting or flux cancellation scenario inside a magnetic fan-spine structure. In total, our radio observations allow us to better understand the evolution of a flux rope eruption and its associated electron acceleration sites, from eruption initiation to propagation into the corona.

  12. Temperature reconstruction and volcanic eruption signal from tree-ring width and maximum latewood density over the past 304 years in the southeastern Tibetan Plateau.

    Science.gov (United States)

    Li, Mingqi; Huang, Lei; Yin, Zhi-Yong; Shao, Xuemei

    2017-11-01

    This study presents a 304-year mean July-October maximum temperature reconstruction for the southeastern Tibetan Plateau based on both tree-ring width and maximum latewood density data. The reconstruction explained 58% of the variance in July-October maximum temperature during the calibration period (1958-2005). On the decadal scale, we identified two prominent cold periods during AD 1801-1833 and 1961-2003 and two prominent warm periods during AD 1730-1800 and 1928-1960, which are consistent with other reconstructions from the nearby region. Based on the reconstructed temperature series and volcanic eruption chronology, we found that most extreme cold years were in good agreement with major volcanic eruptions, such as 1816 after the Tambora eruption in 1815. Also, clusters of volcanic eruptions probably made the 1810s the coldest decade in the past 300 years. Our results indicated that fingerprints of major volcanic eruptions can be found in the reconstructed temperature records, while the responses of regional climate to these eruption events varied in space and time in the southeastern Tibetan Plateau.

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

    Science.gov (United States)

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

    1987-01-01

    Major slope failures are a significant degradational process at volcanoes. Slope failures and associated explosive eruptions have resulted in more than 20 000 fatalities in the past 400 years; the historic record provides evidence for at least six of these events in the past century. Several historic debris avalanches exceed 1 km3 in volume. Holocene avalanches an order of magnitude larger have traveled 50-100 km from the source volcano and affected areas of 500-1500 km2. Historic eruptions associated with major slope failures include those with a magmatic component (Bezymianny type) and those solely phreatic (Bandai type). The associated gravitational failures remove major segments of the volcanoes, creating massive horseshoe-shaped depressions commonly of caldera size. The paroxysmal phase of a Bezymianny-type eruption may include powerful lateral explosions and pumiceous pyroclastic flows; it is often followed by construction of lava dome or pyroclastic cone in the new crater. Bandai-type eruptions begin and end with the paroxysmal phase, during which slope failure removes a portion of the edifice. Massive volcanic landslides can also occur without related explosive eruptions, as at the Unzen volcano in 1792. The main potential hazards from these events derive from lateral blasts, the debris avalanche itself, and avalanche-induced tsunamis. Lateral blasts produced by sudden decompression of hydrothermal and/or magmatic systems can devastate areas in excess of 500km2 at velocities exceeding 100 m s-1. The ratio of area covered to distance traveled for the Mount St. Helens and Bezymianny lateral blasts exceeds that of many pyroclastic flows or surges of comparable volume. The potential for large-scale lateral blasts is likely related to the location of magma at the time of slope failure and appears highest when magma has intruded into the upper edifice, as at Mount St. Helens and Bezymianny. Debris avalanches can move faster than 100 ms-1 and travel tens of

  14. Large explosive basaltic eruptions at Katla volcano, Iceland: Fragmentation, grain size and eruption dynamics

    Science.gov (United States)

    Schmith, Johanne; Höskuldsson, Ármann; Holm, Paul Martin; Larsen, Guðrún

    2018-04-01

    Katla volcano in Iceland produces hazardous large explosive basaltic eruptions on a regular basis, but very little quantitative data for future hazard assessments exist. Here details on fragmentation mechanism and eruption dynamics are derived from a study of deposit stratigraphy with detailed granulometry and grain morphology analysis, granulometric modeling, componentry and the new quantitative regularity index model of fragmentation mechanism. We show that magma/water interaction is important in the ash generation process, but to a variable extent. By investigating the large explosive basaltic eruptions from 1755 and 1625, we document that eruptions of similar size and magma geochemistry can have very different fragmentation dynamics. Our models show that fragmentation in the 1755 eruption was a combination of magmatic degassing and magma/water-interaction with the most magma/water-interaction at the beginning of the eruption. The fragmentation of the 1625 eruption was initially also a combination of both magmatic and phreatomagmatic processes, but magma/water-interaction diminished progressively during the later stages of the eruption. However, intense magma/water interaction was reintroduced during the final stages of the eruption dominating the fine fragmentation at the end. This detailed study of fragmentation changes documents that subglacial eruptions have highly variable interaction with the melt water showing that the amount and access to melt water changes significantly during eruptions. While it is often difficult to reconstruct the progression of eruptions that have no quantitative observational record, this study shows that integrating field observations and granulometry with the new regularity index can form a coherent model of eruption evolution.

  15. Characteristics of EIT Dimmings in Solar Eruptions

    Science.gov (United States)

    Adams, Mitzi; Sterling, A. C.

    2006-01-01

    Intensity "dimmings" in coronal images are a key feature of solar eruptions. Such dimmings are likely the source locations for much of the material expelled in coronal mass ejections (CMEs). Characteristics such as the timing of the dimmings with respect to the onset of other eruption signatures, and the location of the dimmings in the context of the magnetic field environment of the erupting region, are indicative of the mechanism leading to the eruption. We examine dimmings of six eruptions in images from the EUV Imaging Telescope (EIT) on SOHO, along with supplementary soft X-ray (SXR) data from GOES and the SXR Telescope (SXT) on Yohkoh. We examine the timing of the dimming onset and compare with the time of EUV and SXR brightening and determine the timescale for the recovery from dimming for each event. With line-of-sight photospheric magnetograms from the MDI instrument on SOHO, we determine the magnetic structure of the erupting regions and the locations of the dimmings in those regions. From our analysis we consider which mechanism likely triggered each eruption: internal tether cutting, external tether cutting ("breakout"), loss of equilibrium, or some other mechanism.

  16. Plasma Evolution within an Erupting Coronal Cavity

    Science.gov (United States)

    Long, David M.; Harra, Louise K.; Matthews, Sarah A.; Warren, Harry P.; Lee, Kyoung-Sun; Doschek, George A.; Hara, Hirohisa; Jenkins, Jack M.

    2018-03-01

    Coronal cavities have previously been observed to be associated with long-lived quiescent filaments and are thought to correspond to the associated magnetic flux rope. Although the standard flare model predicts a coronal cavity corresponding to the erupting flux rope, these have only been observed using broadband imaging data, restricting an analysis to the plane-of-sky. We present a unique set of spectroscopic observations of an active region filament seen erupting at the solar limb in the extreme ultraviolet. The cavity erupted and expanded rapidly, with the change in rise phase contemporaneous with an increase in nonthermal electron energy flux of the associated flare. Hot and cool filamentary material was observed to rise with the erupting flux rope, disappearing suddenly as the cavity appeared. Although strongly blueshifted plasma continued to be observed flowing from the apex of the erupting flux rope, this outflow soon ceased. These results indicate that the sudden injection of energy from the flare beneath forced the rapid eruption and expansion of the flux rope, driving strong plasma flows, which resulted in the eruption of an under-dense filamentary flux rope.

  17. Myth and catastrophic reality: using cosmogonic mythology to identify cosmic impacts and massive plinian eruptions in holocene South America.

    Energy Technology Data Exchange (ETDEWEB)

    Masse, W. B. (William Bruce)

    2004-01-01

    Major natural catastrophes (e.g., 'universal' floods, fire, darkness, and sky falling down) are prominently reflected in traditional South American creation myths, cosmology, religion, and worldview. We are now beginning to recognize that cosmogonic myths represent a rich and largely untapped data set concerning the most dramatic natural events and processes experienced by each cultural group during the past several thousand years. Observational details regarding specific catastrophes are encoded in myth storylines, typically cast in terms of supernatural characters and actions. Not only are the myths amenable to scientific analysis, but also some sets of myths encode multiple catastrophes in meaningful relative chronological order. The present study considers more than 4200 myths, including more than 260 'universal' catastrophe myths from cultural groups throughout South America. These myths are examined in light of available geological, paleoenvironmental, archeological, and documentary evidence. Our analysis reveals three possible ultra-plinian volcanic eruptions, two in Columbia and the other in the Gran Chaco, the latter likely associated with a poorly dated late Holocene eruption of Nuevo Mundo in central Bolivia. Our analysis also identifies a set of traditions likely linked with the well-known Campo del Cielo iron meteorite impact in northern Argentina originally hypothesized to have occurred around 4000 years ago. Intriguingly, these traditions strongly suggest that the Campo del Cielo impact triggered widespread mass fires in the Gran Chaco region and possibly in the Brazilian Highlands. Several other potential cosmic impacts, distinct from Campo del Cielo, are hinted at in the mythology of other locations in South America. The numerous catastrophe myths in the Gran Chaco region exhibit the most coherent chronological sequence of any South American region. The sequence begins with a 'Great Flood,' by far the most widespread

  18. Distribution and mass of tephra-fall deposits from volcanic eruptions of Sakurajima Volcano based on posteruption surveys

    Science.gov (United States)

    Oishi, Masayuki; Nishiki, Kuniaki; Geshi, Nobuo; Furukawa, Ryuta; Ishizuka, Yoshihiro; Oikawa, Teruki; Yamamoto, Takahiro; Nanayama, Futoshi; Tanaka, Akiko; Hirota, Akinari; Miwa, Takahiro; Miyabuchi, Yasuo

    2018-04-01

    We estimate the total mass of ash fall deposits for individual eruptions of Sakurajima Volcano, southwest Japan based on distribution maps of the tephra fallout. Five ash-sampling campaigns were performed between 2011 and 2015, during which time Sakurajima continued to emit ash from frequent Vulcanian explosions. During each survey, between 29 and 53 ash samplers were installed in a zone 2.2-43 km downwind of the source crater. Total masses of erupted tephra were estimated using several empirical methods based on the relationship between the area surrounded by a given isopleth and the thickness of ash fall within each isopleth. We obtained 70-40,520 t (4.7 × 10-8-2.7 × 10-5-km3 DRE) as the minimum estimated mass of erupted materials for each eruption period. The minimum erupted mass of tephra produced during the recorded events was calculated as being 890-5140 t (5.9 × 10-7-3.6 × 10-6-km3 DRE). This calculation was based on the total mass of tephra collected during any one eruptive period and the number of eruptions during that period. These values may thus also include the contribution of continuous weak ash emissions before and after prominent eruptions. We analyzed the meteorological effects on ash fall distribution patterns and concluded that the width of distribution area of an ash fall is strongly controlled by the near-ground wind speed. The direction of the isopleth axis for larger masses is affected by the local wind direction at ground level. Furthermore, the wind direction influences the direction of the isopleth axes more at higher altitude. While a second maximum of ash fall can appear, the influence of rain might only affect the finer particles in distal areas.

  19. Head turning as a prominent motor symptom in status epilepticus.

    Science.gov (United States)

    Bauer, Gerhard; Broessner, Gregor; Unterberger, Iris; Walser, Gerald; Pfausler, Bettina; Trinka, Eugen

    2008-06-01

    Head and eye turning is frequently observed during seizures. Versions with tonic and/or clonic symptoms can be differentiated from smooth head deviations. Head turning as a prominent symptom of status epilepticus has not previously been reported. We present eight case reports, (7 women/1 man, mean age 41 years, median 41.5, range 10 to 74), of status epilepticus (SE), with head turning as a prominent motor symptom. Six were accompanied by continuous frontal, occipital and temporal ictal epileptiform discharges. Furthermore, two patients had absence status with rhythmic and clonic head versions. While the localizing significance of head turnings in SE is low, in our cases, the direction was away from the discharging hemisphere in all cases of focal SE regardless of whether the turning was classified as version (three cases) or deviation (three cases). In this small series of SE, the classical observation of a patient looking away from the discharging hemisphere is still valid.

  20. Non-LTE hydrogen-line formation in moving prominences

    Science.gov (United States)

    Heinzel, P.; Rompolt, B.

    1986-01-01

    The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

  1. STRUCTURE OF PROMINENCE LEGS: PLASMA AND MAGNETIC FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Levens, P. J.; Labrosse, N. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Schmieder, B. [Observatoire de Paris, Meudon, F-92195 (France); Ariste, A. López, E-mail: p.levens.1@research.gla.ac.uk [Institut de Recherche en Astrophysique et Planétologie, Toulouse (France)

    2016-02-10

    We investigate the properties of a “solar tornado” observed on 2014 July 15, and aim to link the behavior of the plasma to the internal magnetic field structure of the associated prominence. We made multi-wavelength observations with high spatial resolution and high cadence using SDO/AIA, the Interface Region Imaging Spectrograph (IRIS) spectrograph, and the Hinode/Solar Optical Telescope (SOT) instrument. Along with spectropolarimetry provided by the Télescope Héliographique pour l’Etude du Magnétisme et des Instabilités Solaires telescope we have coverage of both optically thick emission lines and magnetic field information. AIA reveals that the two legs of the prominence are strongly absorbing structures which look like they are rotating, or oscillating in the plane of the sky. The two prominence legs, which are both very bright in Ca ii (SOT), are not visible in the IRIS Mg ii slit-jaw images. This is explained by the large optical thickness of the structures in Mg ii, which leads to reversed profiles, and hence to lower integrated intensities at these locations than in the surroundings. Using lines formed at temperatures lower than 1 MK, we measure relatively low Doppler shifts on the order of ±10 km s{sup −1} in the tornado-like structure. Between the two legs we see loops in Mg ii, with material flowing from one leg to the other, as well as counterstreaming. It is difficult to interpret our data as showing two rotating, vertical structures that are unrelated to the loops. This kind of “tornado” scenario does not fit with our observations. The magnetic field in the two legs of the prominence is found to be preferentially horizontal.

  2. Beat gestures and prosodic prominence: impact on learning

    OpenAIRE

    Kushch, Olga

    2018-01-01

    Previous research has shown that gestures are beneficial for language learning. This doctoral thesis centers on the effects of beat gestures– i.e., hand and arm gestures that are typically associated with prosodically prominent positions in speech - on such processes. Little is known about how the two central properties of beat gestures, namely how they mark both information focus and rhythmic positions in speech, can be beneficial for learning either a first or a second language. The main go...

  3. Permanent molars: Delayed development and eruption

    Directory of Open Access Journals (Sweden)

    Arathi R

    2006-05-01

    Full Text Available Delayed development and eruption of all the permanent molars is a rare phenomenon, which can cause disturbance in the developing occlusion. The eruption of permanent first and second molars is very important for the coordination of facial growth and for providing sufficient occlusal support for undisturbed mastication. In the case described, the first permanent molars were delayed in their development and were seen erupting at the age of nine and a half years. Severe disparity between the left and the right side of the dentition with respect to the rate of development of molars were also present.

  4. Emotional Eruptions, Volcanic Activity and Global Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2011-01-01

    The eruption of Iceland’s Eyjafjallajökull volcano in April 2010 set off a number of environmental, economic and cultural effects obstructing thousands of people in the midst of their global mobility flows. It halted, as well, the exchange of goods and commodities and exposed the vulnerability...... of the global aeromobility system. In this paper an account is given of how the event was experienced by a European academic attending a number of North American conferences at precisely the time of the eruption. The paper is an attempt to describe how people reacted emotionally as well as rationally......, attempting to find strategies for coping with the consequences of the eruption....

  5. Prominence and tornado dynamics observed with IRIS and THEMIS

    Science.gov (United States)

    Schmieder, Brigitte; Levens, Peter; Labrosse, Nicolas; Mein, Pierre; Lopez Ariste, Arturo; Zapior, Maciek

    2017-08-01

    Several prominences were observed during campaigns in September 2013 and July 2014 with the IRIS spectrometer and the vector magnetograph THEMIS (Tenerife). SDO/AIA and IRIS provided images and spectra of prominences and tornadoes corresponding to different physical conditions of the transition region between the cool plasma and the corona. The vector magnetic field was derived from THEMIS observations by using the He D3 depolarisation due to the magnetic field. The inversion code (PCA) takes into account the Hanle and Zeeman effects and allows us to compute the strength and the inclination of the magnetic field which is shown to be mostly horizontal in prominences as well as in tornadoes. Movies from SDO/AIA in 304 A and Hinode/SOT in Ca II show the highly dynamic nature of the fine structures. From spectra in Mg II and Si IV lines provided by IRIS and H-alpha observed by the Multi-channel Subtractive Double Pass (MSDP) spectrograph in the Meudon Solar Tower we derived the Doppler shifts of the fine structures and reconstructed the 3D structure of tornadoes. We conclude that the apparent rotation of AIA tornadoes is due to large-scale quasi-periodic oscillations of the plasma along more or less horizontal magnetic structures.

  6. Post-eruptive flooding of Santorini caldera and implications for tsunami generation

    Science.gov (United States)

    Nomikou, P.; Druitt, T. H.; Hübscher, C.; Mather, T. A.; Paulatto, M.; Kalnins, L. M.; Kelfoun, K.; Papanikolaou, D.; Bejelou, K.; Lampridou, D.; Pyle, D. M.; Carey, S.; Watts, A. B.; Weiß, B.; Parks, M. M.

    2016-01-01

    Caldera-forming eruptions of island volcanoes generate tsunamis by the interaction of different eruptive phenomena with the sea. Such tsunamis are a major hazard, but forward models of their impacts are limited by poor understanding of source mechanisms. The caldera-forming eruption of Santorini in the Late Bronze Age is known to have been tsunamigenic, and caldera collapse has been proposed as a mechanism. Here, we present bathymetric and seismic evidence showing that the caldera was not open to the sea during the main phase of the eruption, but was flooded once the eruption had finished. Inflow of water and associated landsliding cut a deep, 2.0–2.5 km3, submarine channel, thus filling the caldera in less than a couple of days. If, as at most such volcanoes, caldera collapse occurred syn-eruptively, then it cannot have generated tsunamis. Entry of pyroclastic flows into the sea, combined with slumping of submarine pyroclastic accumulations, were the main mechanisms of tsunami production. PMID:27824353

  7. Reconstructing the deadly eruptive events of 1790 CE at Kīlauea Volcano, Hawai‘i

    Science.gov (United States)

    Swanson, Don; Weaver, Samantha J; Houghton, Bruce F.

    2014-01-01

    A large number of people died during an explosive eruption of Kīlauea Volcano in 1790 CE. Detailed study of the upper part of the Keanakāko‘i Tephra has identified the deposits that may have been responsible for the deaths. Three successive units record shifts in eruption style that agree well with accounts of the eruption based on survivor interviews 46 yr later. First, a wet fall of very fine, accretionary-lapilli–bearing ash created a “cloud of darkness.” People walked across the soft deposit, leaving footprints as evidence. While the ash was still unconsolidated, lithic lapilli fell into it from a high eruption column that was seen from 90 km away. Either just after this tephra fall or during its latest stage, pulsing dilute pyroclastic density currents, probably products of a phreatic eruption, swept across the western flank of Kīlauea, embedding lapilli in the muddy ash and crossing the trail along which the footprints occur. The pyroclastic density currents were most likely responsible for the fatalities, as judged from the reported condition and probable location of the bodies. This reconstruction is relevant today, as similar eruptions will probably occur in the future at Kīlauea and represent its most dangerous and least predictable hazard.

  8. Seeking a paleontological signature for mass extinctions caused by flood basalt eruptions

    Science.gov (United States)

    Payne, J.; Bush, A. M.; Chang, E. T.; Heim, N. A.; Knope, M. L.; Pruss, S. B.

    2016-12-01

    Flood basalt eruptions coincide with numerous extinction events in the fossil record. Increasingly precise absolute age determinations for both the timing of eruption and of species extinctions have strengthened the case for flood basalt eruptions as the single most important trigger for major mass extinction events in the fossil record. However, the extent to which flood basalt eruptions cause a pattern of biotic loss distinctive from extinctions triggered by other geological or biological processes remains an open question. In the absence of diagnostic mapping between geological triggers and biological losses, establishing the identities of causal agents for mass extinctions will continue to depend primarily on evidence for temporal coincidence. Here we use a synoptic database of marine animal genera spanning the Phanerozoic, including times of first and last occurrence, body size, motility, life position, feeding mode, and respiratory physiology to assess whether extinction events temporally associated with flood basalt eruptions exhibit a diagnostic pattern of extinction selectivity. We further ask whether any events not associated with known large igneous provinces nevertheless display extinction patterns suggestive of such a cause. Finally, we ask whether extinction events associated with other primary causes, such as glaciation or bolide impact, are distinguishable from events apparently triggered by flood basalt eruptions on the basis of extinction selectivity patterns

  9. Active Volcanic Eruptions on Io

    Science.gov (United States)

    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 images can

  10. Synthetic differential emission measure curves of prominence fine structures. II. The SoHO/SUMER prominence of 8 June 2004

    Czech Academy of Sciences Publication Activity Database

    Gunár, Stanislav; Parenti, S.; Anzer, U.; Heinzel, Petr; Vial, J. C.

    2011-01-01

    Roč. 535, November (2011), A122/1-A122/11 ISSN 0004-6361 R&D Projects: GA ČR GP205/09/P554; GA ČR GA205/09/1705; GA ČR GAP209/10/1706 Institutional research plan: CEZ:AV0Z10030501 Keywords : Sun * filaments * prominences Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.587, year: 2011

  11. 1984 Mauna Loa eruption and planetary geolgoy

    International Nuclear Information System (INIS)

    Moore, H.J.

    1987-01-01

    In planetary geology, lava flows on the Moon and Mars are commonly treated as relatively simple systems. Some of the complexities of actual lava flows are illustrated using the main flow system of the 1984 Mauna Loa eruption. The outline, brief narrative, and results given are based on a number of sources. The implications of the results to planetary geology are clear. Volume flow rates during an eruption depend, in part, on the volatile content of the lava. These differ from the volume flow rates calculated from post eruption flow dimensions and the duration of the eruption and from those using models that assume a constant density. Mass flow rates might be more appropriate because the masses of volatiles in lavas are usually small, but variable and sometimes unknown densities impose severe restrictions on mass estimates

  12. Severe hypertriglyceridemia presenting as eruptive xanthomatosis

    Directory of Open Access Journals (Sweden)

    Sameera S Vangara

    2018-01-01

    Full Text Available Eruptive xanthomatosis is described as the sudden eruption of erythematous yellow papules in the presence of hypertriglyceridemia, often associated with serum triglyceride levels above 2000 mg/dl. Severe hypertriglyceridemia can be caused by primary genetic mutations, secondary chronic diseases, or a combination of both. Uncontrolled diabetes mellitus is a known risk factor. It is imperative for physicians to be aware of eruptive xanthomatosis as a warning sign for severe hypertriglyceridemia due to the underlying risk for the potentially fatal complication of acute pancreatitis. Herein, we discuss a case of a 52-year-old man with uncontrolled diabetes mellitus who presented with eruptive xanthomata and a triglyceride level of 7157 mg/dl, the highest recorded value in the absence of acute pancreatitis, with a remarkable response to drug therapy. A review of the literature is included to discuss the clinical relevance and appropriate treatment of this disease entity.

  13. Polymorphous light eruption - some interesting aspects

    International Nuclear Information System (INIS)

    Corrales-Padilla, H.; Dominguez-Soto, L.; Hojyo-Tomoka, M.T.; Londono, F.; Vargas-Ocampo, F.

    1979-01-01

    A study of polymorphous light eruption (PLE) is Latin America is reported. The clinical lesions, the course, histopathology, differential diagnosis, pathogenesis, treatment and systemic photoprotection are discussed. Treatment with ultraviolet radiation is included. (C.F.)

  14. Depth of origin of magma in eruptions.

    Science.gov (United States)

    Becerril, Laura; Galindo, Ines; Gudmundsson, Agust; Morales, Jose Maria

    2013-09-26

    Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness ratios of feeder dykes can be used to estimate the depth to the source magma chamber. Using this method, accurately measured volcanic fissures/feeder-dykes in El Hierro (Canary Islands) indicate a source depth of 11-15 km, which coincides with the main cloud of earthquake foci surrounding the magma chamber associated with the 2011-2012 eruption of El Hierro. The method can be used on widely available GPS and InSAR data to calculate the depths to the source magma chambers of active volcanoes worldwide.

  15. Tephra from the 1979 soufriere explosive eruption.

    Science.gov (United States)

    Sigurdsson, H

    1982-06-04

    The explosive phase of the 1979 Soufriere eruption produced 37.5 x 10(6) cubic meters (dense-rock equivalent) of tephra, consisting of about 40 percent juvenile basaltic andesite and 60 percent of a nonjuvenile component derived from the fragmentation of the 1971-1972 lava island during phreatomagmatic explosions. The unusually fine grain size, poor sorting, and bimodality of the land deposit are attributed to particle aggregation and the formation of accretionary lapilli in a wet eruption column.

  16. Asymptomatic Petechial Eruption on the Lower Legs

    OpenAIRE

    Mendese, Gary; Grande, Donald

    2013-01-01

    The authors report an unusual case of Rocky Mountain spotted fever that presented as an asymptomatic petechial eruption on the lower legs. Rocky Mountain spotted fever is rare in New England and, as such, is typically not on the differential diagnosis when presented with such patients. What began as an asymptomatic eruption progressed to more classic signs of the disease, including a positive Rocky Mountain spotted fever titer. The patient was successfully treated with doxycydine and within a...

  17. ERUPTION PATTERN OF PERMANENT TEETH -IN TANZANIA ...

    African Journals Online (AJOL)

    was visible in the oral vacity. Generally permanent teeth erupted earlier in girls than in boys. The differences were 0.1 - 0.2 years for incisors and first molars, 0.2 - 0.4 years for canines and premolars and 0.3 - 0.5 years for second molars. Except for the second premolars, mandibular teeth erupted earlier than the maxillary in ...

  18. The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation

    Science.gov (United States)

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

    2018-04-01

    Combined zircon U-Th-Pb and (U-Th)/He dating was applied to refine the eruption chronology of the last 2 Myr for the andesitic and dacitic Pilişca volcano and Ciomadul Volcanic Dome Complex (CVDC), the youngest volcanic area of the Carpathian-Pannonian region, located in the southernmost Harghita, eastern-central Europe. The proposed eruption ages, which are supported also by the youngest zircon crystallization ages, are much younger than the previously determined K/Ar ages. By dating every known eruption center in the CVDC, repose times between eruptive events were also accurately determined. Eruption of the andesite at Murgul Mare (1865 ± 87 ka) and dacite of the Pilişca volcanic complex (1640 ± 37 ka) terminated an earlier pulse of volcanic activity within the southernmost Harghita region, west of the Olt valley. This was followed by the onset of the volcanism in the CVDC, which occurred after several 100s kyr of eruptive quiescence. At ca. 1 Ma a significant change in the composition of erupted magma occurred from medium-K calc-alkaline compositions to high-K dacitic (Baba-Laposa dome at 942 ± 65 ka) and shoshonitic magmas (Malnaş and Bixad domes; 964 ± 46 ka and 907 ± 66 ka, respectively). Noteworthy, eruptions of magmas with distinct chemical compositions occurred within a restricted area, a few km from one another. These oldest lava domes of the CVDC form a NNE-SSW striking tectonic lineament along the Olt valley. Following a brief (ca. 100 kyr) hiatus, extrusion of high-K andesitic magma continued at Dealul Mare (842 ± 53 ka). After another ca. 200 kyr period of quiescence two high-K dacitic lava domes extruded (Puturosul: 642 ± 44 ka and Balvanyos: 583 ± 30 ka). The Turnul Apor lava extrusion occurred after a ca. 200 kyr repose time (at 344 ± 33 ka), whereas formation of the Haramul Mic lava dome (154 ± 16 ka) represents the onset of the development of the prominent Ciomadul volcano. The accurate determination of eruption dates shows that the

  19. Magma transfer at Campi Flegrei caldera (Italy) before the 1538 AD eruption

    Science.gov (United States)

    Di Vito, Mauro A.; Acocella, Valerio; Aiello, Giuseppe; Barra, Diana; Battaglia, Maurizio; Carandente, Antonio; Del Gaudio, Carlo; de Vita, Sandro; Ricciardi, Giovanni; Rico, Ciro; Scandone, Roberto; Terrasi, Filippo

    2017-04-01

    Defining and understanding the shallow transfer of magma at volcanoes is crucial to forecast eruptions, possibly the ultimate goal of volcanology. This is particularly challenging at felsic calderas experiencing unrest, which typically includes significant changes in seismicity, deformation and degassing rates. Caldera unrest is particularly frequent, affects wide areas and often does not culminate in an eruption. Moreover its evidence is usually complicated by the presence of a hydrothermal system. As a result, forecasting any eruption and vent-opening sites within a caldera is very difficult. The Campi Flegrei caldera (CFc), in the densely inhabited area of Naples (Italy), is commonly considered one of the most dangerous active volcanic systems. CFc is a 12 km wide depression hosting two nested calderas formed during the eruptions of the Campanian Ignimbrite ( 39 ka) and the Neapolitan Yellow Tuff ( 15 ka). In the last 5 ka, resurgence, with uplift >60 m close to the central part of the caldera, was accompanied by volcanism between 4.8 and 3.8 ka. After 3 ka of quiescence, increasing seismicity and uplift preceded the last eruption at Monte Nuovo in 1538 for several decades. The most recent activity culminated in four unrest episodes between 1950-1952, 1969-1972, 1982-1984 and 2005-Present, with a cumulative uplift at Pozzuoli of 4.5 m; the present unrest episode has been interpreted as being magma-driven. These unrest episodes are considered the most evident expression of a longer-term (centuries or more) restless activity. The post-1980 deformation largely results from a magmatic oblate or sill-like source at 4 km depth below Pozzuoli. Despite the restless activity of CFc, the recent unrest episodes did not culminate in eruption, so that any possibility to define the pre-eruptive shallow transfer of magma remains elusive. Indeed, this definition is a crucial step in order to identify and understand pre-eruptive processes, and thus to make any forecast. To fill

  20. Electrostatic phenomena in volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Lane, S J; James, M R; Gilbert, J S, E-mail: s.lane@lancaster.ac.uk [Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

    2011-06-23

    Electrostatic phenomena have long been associated with the explosive eruption of volcanoes. Lightning generated in volcanic plumes is a spectacular atmospheric electrical event that requires development of large potential gradients over distances of up to kilometres. This process begins as hydrated liquid rock (magma) ascends towards Earth's surface. Pressure reduction causes water supersaturation in the magma and the development of bubbles of supercritical water, where deeper than c. 1000 m, and water vapour at shallower depths that drives flow expansion. The generation of high strain rates in the expanding bubbly magma can cause it to fracture in a brittle manner, as deformation relaxation timescales are exceeded. The brittle fracture provides the initial charge separation mechanism, known as fractoemission. The resulting mixture of charged silicate particles and ions evolves over time, generating macro-scale potential gradients in the atmosphere and driving processes such as particle aggregation. For the silicate particles, aggregation driven by electrostatic effects is most significant for particles smaller than c. 100 {mu}m. Aggregation acts to change the effective aerodynamic behaviour of silicate particles, thus altering the sedimentation rates of particles from volcanic plumes from the atmosphere. The presence of liquid phases also promotes aggregation processes and lightning.

  1. Reduced cooling following future volcanic eruptions

    Science.gov (United States)

    Hopcroft, Peter O.; Kandlbauer, Jessy; Valdes, Paul J.; Sparks, R. Stephen J.

    2017-11-01

    Volcanic eruptions are an important influence on decadal to centennial climate variability. Large eruptions lead to the formation of a stratospheric sulphate aerosol layer which can cause short-term global cooling. This response is modulated by feedback processes in the earth system, but the influence from future warming has not been assessed before. Using earth system model simulations we find that the eruption-induced cooling is significantly weaker in the future state. This is predominantly due to an increase in planetary albedo caused by increased tropospheric aerosol loading with a contribution from associated changes in cloud properties. The increased albedo of the troposphere reduces the effective volcanic aerosol radiative forcing. Reduced sea-ice coverage and hence feedbacks also contribute over high-latitudes, and an enhanced winter warming signal emerges in the future eruption ensemble. These findings show that the eruption response is a complex function of the environmental conditions, which has implications for the role of eruptions in climate variability in the future and potentially in the past.

  2. Ilchulbong tuff cone, Jeju Island, Korea, revisited: A compound monogenetic volcano involving multiple magma batches, shifting vents, and discrete eruptive phases

    Science.gov (United States)

    Sohn, Y.; Brenna, M.; Smith, I. E.; Nemeth, K.; White, J. D.; Murtagh, R.; Jeon, Y.; Kwon, C.; Cronin, S. J.

    2010-12-01

    Ilchulbong (Sunrise Peak) tuff cone is a UNESCO World Heritage site that owes its scientific importance to the outstanding coastal exposures that surround it. It is also one of the classic sites that provided the sedimentary evidence for the primary pyroclastic processes that occur during phreatomagmatic basaltic eruptions. It has been long considered, based on the cone morphology, that this classic cone was produced via eruption from a single vent site. Reanalysis of the detailed sedimentary sequence has now revealed that two subtle paraconformities occur in this deposition sequence, one representing a significant time break of perhaps days to weeks or months, during which erosion and compaction of the lower cone occurred, the conduit cooled and solidified and a subsequent resumption of eruption took place in a new vent location. Detailed geochemical study of the juvenile clasts through this cone reveals that three separate alkali basaltic magma batches were erupted, the first and third erupted may be genetically related, with the latter showing evidence for longer periods of shallow-level fractionation. The second magma batch erupted was generated in a different mantle source area. Reconstructing the eruption sequence, the lower Ilchulbong cone was formed by eruption of magma 1. Cessation of eruption was accompanied by erosion to generate a volcano-wide unconformity, associated with reworked deposits in the lower cone flanks. The eruption resumed with magma 2 that, due to the cooled earlier conduit, was forced to erupt in a new site to the west of the initial vent. This formed the middle cone sequence over the initially formed structure. The third magma batch erupted with little or no interval after magma 2 from the same vent location, associated with cone instability and slumping, and making up the deposits of the upper cone. These results demonstrate how critical the examination for sedimentary evidence for time breaks in such eruption sequences is for

  3. Relationship between eruption plume heights and seismic source amplitudes of eruption tremors and explosion events

    Science.gov (United States)

    Mori, A.; Kumagai, H.

    2016-12-01

    It is crucial to analyze and interpret eruption tremors and explosion events for estimating eruption size and understanding eruption phenomena. Kumagai et al. (EPS, 2015) estimated the seismic source amplitudes (As) and cumulative source amplitudes (Is) for eruption tremors and explosion events at Tungurahua, Ecuador, by the amplitude source location (ASL) method based on the assumption of isotropic S-wave radiation in a high-frequency band (5-10 Hz). They found scaling relations between As and Is for eruption tremors and explosion events. However, the universality of these relations is yet to be verified, and the physical meanings of As and Is are not clear. In this study, we analyzed the relations between As and Is for eruption tremors and explosion events at active volcanoes in Japan, and estimated As and Is by the ASL method. We obtained power-law relations between As and Is, in which the powers were different between eruption tremors and explosion events. These relations were consistent with the scaling relations at Tungurahua volcano. Then, we compared As with maximum eruption plume heights (H) during eruption tremors analyzed in this study, and found that H was proportional to 0.21 power of As. This relation is similar to the plume height model based on the physical process of plume rise, which indicates that H is proportional to 0.25 power of volumetric flow rate for plinian eruptions. This suggests that As may correspond to volumetric flow rate. If we assume a seismic source with volume changes and far-field S-wave, As is proportional to the source volume rate. This proportional relation and the plume height model give rise to the relation that H is proportional to 0.25 power of As. These results suggest that we may be able to estimate plume heights in realtime by estimating As during eruptions from seismic observations.

  4. Experimental Constraints on Forecasting the Location of Volcanic Eruptions from Pre-eruptive Surface Deformation

    Directory of Open Access Journals (Sweden)

    Frank Guldstrand

    2018-02-01

    Full Text Available Volcanic eruptions pose a threat to lives and property when volcano flanks and surroundings are densely populated. The local impact of an eruption depends firstly on its location, whether it occurs near a volcano summit, or down on the flanks. Then forecasting, with a defined accuracy, the location of a potential, imminent eruption would significantly improve the assessment and mitigation of volcanic hazards. Currently, the conventional volcano monitoring methods based on the analysis of surface deformation assesses whether a volcano may erupt but are not implemented to locate imminent eruptions in real time. Here we show how surface deformation induced by ascending eruptive feeders can be used to forecast the eruption location through a simple geometrical analysis. Our analysis builds on the results of 33 scaled laboratory experiments simulating the emplacement of viscous magma intrusions in a brittle, cohesive Coulomb crust under lithostatic stress conditions. The intrusion-induced surface deformation was systematically monitored at high spatial and temporal resolution. In all the experiments, surface deformation preceding the eruptions resulted in systematic uplift, regardless of the intrusion shape. The analysis of the surface deformation patterns leads to the definition of a vector between the center of the uplifted area and the point of maximum uplift, which systematically acted as a precursor to the eruption's location. The temporal evolution of this vector indicated the direction in which the subsequent eruption would occur and ultimately the location itself, irrespective of the feeder shapes. Our findings represent a new approach on how surface deformation on active volcanoes that are not in active rifts could be analysed and used prior to an eruption with a real potential to improve hazard mitigation.

  5. On magma fragmentation by conduit shear stress: Evidence from the Kos Plateau Tuff, Aegean Volcanic Arc

    Science.gov (United States)

    Palladino, Danilo M.; Simei, Silvia; Kyriakopoulos, Konstantinos

    2008-12-01

    Large silicic explosive eruptions are the most catastrophic volcanic events. Yet, the intratelluric mechanisms underlying are not fully understood. Here we report a field and laboratory study of the Kos Plateau Tuff (KPT, 161 ka, Aegean Volcanic Arc), which provides an excellent geological example of conduit processes that control magma vesiculation and fragmentation during intermediate- to large-scale caldera-forming eruptions. A prominent feature of the KPT is the occurrence of quite unusual platy-shaped tube pumice clasts in pyroclastic fall and current deposits from the early eruption phases preceding caldera collapse. On macroscopic and SEM observations, flat clast faces are elongated parallel to tube vesicles, while transverse surfaces often occur at ~ 45° to vesicle elongation. This peculiar pumice texture provides evidence of high shear stresses related to strong velocity gradients normal to conduit walls, which induced vesiculation and fragmentation of the ascending magma. Either an increasing mass discharge rate without adequate enlargement of a narrow central feeder conduit or a developing fissure-like feeder system related to incipient caldera collapse provided suitable conditions for the generation of plate tube pumice within magma volumes under high shear during the pre-climactic KPT eruption phases. This mechanism implies that the closer to the conduit walls (where the stronger are the velocity gradients) the larger was the proportion of plate vs. conventional (lensoid) juvenile fragments in the ascending gas-pyroclast mixture. Consequently, plate pumice clasts were mainly entrained in the outer portions of the jet and convecting regions of a sustained, Plinian-type, eruption column, as well as in occasional lateral blast currents generated at the vent. As a whole, plate pumice clasts in the peripheral portions of the column were transported at lower altitudes and deposited by fallout or partial collapse closer to the vent relative to lensoid ones

  6. Perceptions of Social Responsibility of Prominent Animal Welfare Groups.

    Science.gov (United States)

    Widmar, Nicole J Olynk; Morgan, Carissa J; Croney, Candace C

    2018-01-01

    Nonhuman animal welfare is an increasingly important component of consumer expectations of corporate social responsibility (CSR). The extent to which prominent animal welfare or protection organizations may influence people's perceptions of food industry CSR may be related to an organization's perceived social responsibility. Data from an online survey of 300 U.S. residents were used to explore relationships between demographics/lifestyle choices and perceptions of prominent animal welfare organizations (using best-worst scaling methodology). Overall, the American Society for the Prevention of Cruelty to Animals was perceived to be the most socially responsible organization analyzed, followed by the Humane Society of the United States and the American Humane Association (AHA). Results suggest that the perceived social responsibility of animal protection organizations in this study was not strongly linked to personally (financially) supporting them, with 2 exceptions: the perceptions of People for the Ethical Treatment of Animals and AHA. Improved understanding of the perception of animal welfare or protection organizations can inform decision making by organizations interested in furthering animal welfare causes.

  7. Word-level prominence in Persian: An Experimental Study.

    Science.gov (United States)

    Sadeghi, Vahid

    2017-12-01

    Previous literature on the phonetics of stress in Persian has reported that fundamental frequency is the only reliable acoustic correlate of stress, and that stressed and unstressed syllables are not differentiated from each other in the absence of accentuation. In this study, the effects of lexical stress on duration, overall intensity and spectral tilt were examined in Persian both in the accented and unaccented conditions. Results showed that syllable duration is consistently affected by stress in Persian in both the accented and unaccented conditions across all vowel types. Unlike duration, the results for overall intensity and spectral tilt were significant only in the accented condition, suggesting that measures of intensity are not a correlate of stress in Persian but they are mainly caused by the presence of a pitch movement. The findings are phonologically interpreted as suggesting that word-level prominence in Persian is typologically similar to 'stress accent' languages, in which multiple phonetic cues are used to signal the prominence contrast in the accented condition, and stressed and unstressed syllables are different from each other even when the word is not pitch-accented.

  8. Characterize Eruptive Processes at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Valentine, G.

    2001-01-01

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain shapes

  9. Characterize Eruptive Processes at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    G. Valentine

    2001-12-20

    This Analysis/Model Report (AMR), ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', presents information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a potential repository at Yucca Mountain. Many aspects of this work are aimed at resolution of the Igneous Activity Key Technical Issue (KTI) as identified by the Nuclear Regulatory Commission (NRC 1998, p. 3), Subissues 1 and 2, which address the probability and consequence of igneous activity at the proposed repository site, respectively. Within the framework of the Disruptive Events Process Model Report (PMR), this AMR provides information for the calculations in two other AMRs ; parameters described herein are directly used in calculations in these reports and will be used in Total System Performance Assessment (TSPA). Compilation of this AMR was conducted as defined in the Development Plan, except as noted. The report begins with considerations of the geometry of volcanic feeder systems, which are of primary importance in predicting how much of a potential repository would be affected by an eruption. This discussion is followed by one of the physical and chemical properties of the magmas, which influences both eruptive styles and mechanisms for interaction with radioactive waste packages. Eruptive processes including the ascent velocity of magma at depth, the onset of bubble nucleation and growth in the rising magmas, magma fragmentation, and velocity of the resulting gas-particle mixture are then discussed. The duration of eruptions, their power output, and mass discharge rates are also described. The next section summarizes geologic constraints regarding the interaction between magma and waste packages. Finally, they discuss bulk grain size produced by relevant explosive eruptions and grain

  10. A FLUX ROPE ERUPTION TRIGGERED BY JETS

    International Nuclear Information System (INIS)

    Guo Juan; Zhang Hongqi; Deng Yuanyong; Lin Jiaben; Su Jiangtao; Liu Yu

    2010-01-01

    We present an observation of a filament eruption caused by recurrent chromospheric plasma injections (surges/jets) on 2006 July 6. The filament eruption was associated with an M2.5 two-ribbon flare and a coronal mass ejection (CME). There was a light bridge in the umbra of the main sunspot of NOAA 10898; one end of the filament was terminated at the region close to the light bridge, and recurrent surges were observed to be ejected from the light bridge. The surges occurred intermittently for about 8 hr before the filament eruption, and finally a clear jet was found at the light bridge to trigger the filament eruption. We analyzed the evolutions of the relative darkness of the filament and the loaded mass by the continuous surges quantitatively. It was found that as the occurrence of the surges, the relative darkness of the filament body continued growing for about 3-4 hr, reached its maximum, and kept stable for more than 2 hr until it erupted. If suppose 50% of the ejected mass by the surges could be trapped by the filament channel, then the total loaded mass into the filament channelwill be about 0.57x10 16 g with a momentum of 0.57x10 22 g cm s -1 by 08:08 UT, which is a non-negligible effect on the stability of the filament. Based on the observations, we present a model showing the important role that recurrent chromospheric mass injection play in the evolution and eruption of a flux rope. Our study confirms that the surge activities can efficiently supply the necessary material for some filament formation. Furthermore, our study indicates that the continuous mass with momentum loaded by the surge activities to the filament channel could make the filament unstable and cause it to erupt.

  11. Automatic detection of prominence (as defined by listeners' judgements) in read aloud Dutch sentences

    NARCIS (Netherlands)

    Streefkerk, B.M.; Pols, L.C.W.; ten Bosch, L.F.M.

    1998-01-01

    This paper describes a first step towards the automatic classification of prominence (as defined by native listeners). As a result of a listening experiment each word in 500 sentences was marked with a rating scale between `0' (non-prominent) and `10' (very prominent). These prominence labels are

  12. Somma-Vesuvius Plinian Eruptions fed by mafic magma: insights from bubbles in melt inclusions

    Science.gov (United States)

    Esposito, R.; Redi, D.; Cannatelli, C.; Danyushevsky, L. V.; Lima, A.; Bodnar, R. J.; De Vivo, B.

    2014-12-01

    Mt. Somma-Vesuvius Plinian eruptions were first described by Pliny the younger in 79 AD during the infamous eruption that destroyed Pompeii. Today, such eruptions are still a concern to the nearly 3 million people living in the Naples metropolitan area. Understanding the source for Mt. Somma-Vesuvius magma and the coexisting volatile phase is vital to better constrain the long-term eruptive behavior of this volcano. In the present study, ~ 50 olivine phenocrysts were selected from lavas and pumices produced during mild effusive events referred to as inter-Plinian eruptions, and from highly explosive Plinian eruptions that occurred at Mt. Somma-Vesuvius between 33000 ka and 1631 AD. Selected olivine phenocrysts containing MI were examined petrographically and analyzed for Fo content. Fo varies from 69 to 73 mole% for inter-Plinian olivine crystals and from 84 to 90 mole% with one zoned olivine containing 76-81 mole% Fo, for Plinian olivine crystals. Investigated MI vary from slightly crystallized to highly crystallized. Selected crystallized MI were reheated using the Vernadsky stage, and quenched to a homogeneous glass (Group 1) or glass plus a vapor bubble (Group 2). On one hand, MI of Group 1 are hosted in olivine ranging from Fo72 to Fo76 and were all erupted from the Pompeii eruption (white pumice deposit). On the other hand, MI of Group 2 are trapped in olivine ranging from Fo69 to Fo81 and from Fo84 to Fo90, and the hosts are representative of both Plinian and inter-Plinian events. The only eruption where Group-1 and Group-2 MI coexist is the Pompeii eruption. Group 2 MIs were further analyzed by Raman to test for the presence of volatiles (CO2 or H2O) in the vapor bubbles. CO2 was detected in all MI analyzed. CO2 density was determined using the distance between the two Fermi-diad peaks, and ranges between 0.14 and 0.55 g/cm3. Six MI also showed evidence for H2O in the vapor bubble. In addition, carbonates were detected at the glass-vapor interface of five

  13. Orthodontic treatment for prominent lower front teeth (Class III malocclusion) in children.

    Science.gov (United States)

    Watkinson, Simon; Harrison, Jayne E; Furness, Susan; Worthington, Helen V

    2013-09-30

    Prominent lower front teeth (termed reverse bite; under bite; Class III malocclusion) may be due to a combination of the jaw or tooth positions or both. The upper jaw (maxilla) can be too far back or the lower jaw (mandible) too far forward, or both. Prominent lower front teeth can also occur if the upper front teeth (incisors) are tipped back or the lower front teeth are tipped forwards, or both. Various treatment approaches have been described to correct prominent lower front teeth in children and adolescents. To assess the effects of orthodontic treatment for prominent lower front teeth in children and adolescents. We searched the following databases: Cochrane Oral Health Group's Trials Register (to 7 January 2013), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12), MEDLINE via OVID (1946 to 7 January 2013), and EMBASE via OVID (1980 to 7 January 2013). Randomised controlled trials (RCTs) recruiting children or adolescents or both (aged 16 years or less) receiving any type of orthodontic treatment to correct prominent lower front teeth (Class III malocclusion). Orthodontic treatments were compared with control groups who received either no treatment, delayed treatment or a different active intervention. Screening of references, identification of included and excluded studies, data extraction and assessment of the risk of bias of the included studies was performed independently and in duplicate by two review authors. The mean differences with 95% confidence intervals were calculated for continuous data. Meta-analysis was only undertaken when studies of similar comparisons reported comparable outcome measures. A fixed-effect model was used. The I2 statistic was used as a measure of statistical heterogeneity. Seven RCTs with a total of 339 participants were included in this review. One study was assessed as at low risk of bias, three studies were at high risk of bias, and in the remaining three studies risk of bias

  14. Eruption and degassing dynamics of the major August 2015 Piton de la Fournaise eruption

    Science.gov (United States)

    Di Muro, Andrea; Arellano, Santiago; Aiuppa, Alessandro; Bachelery, Patrick; Boudoire, Guillaume; Coppola, Diego; Ferrazzini, Valerie; Galle, Bo; Giudice, Gaetano; Gurioli, Lucia; Harris, Andy; Liuzzo, Marco; Metrich, Nicole; Moune, Severine; Peltier, Aline; Villeneuve, Nicolas; Vlastelic, Ivan

    2016-04-01

    Piton de la Fournaise (PdF) shield volcano is one of the most active basaltic volcanoes in the World with one eruption every nine months, on average. This frequent volcanic activity is broadly bimodal, with frequent small volume, short lived eruptions (de la Fournaise volcanological observatory (DOAS, MultiGaS, diffuse CO2 soil emissions). Regular lava and tephra sampling was also performed for geochemical and petrological analysis. The eruption was preceded by a significant increase in CO2 soil emissions at distal soil stations (ca. 15 km from the summit), with CO2 enrichment also being recorded at summit low temperature fumaroles. Eruptive products were spectacularly zoned, with plagioclase and pyroxene being abundant in the early erupted products and olivine being the main phase in the late-erupted lavas. Total gas emissions at the eruptive vent underwent a decrease during the first half of the eruption and then an increase, mirroring the time evolution of magma discharge rate (from 5-10 m3/s in September to 15-30 m3/s in late-October) and the progressive change in magma composition. In spite of significant evolution in magma and gas output, CO2/SO2 ratios in high temperature gases remained quite low (< 0.3) and with little temporal change. Geochemical data indicated that this relatively long-lived eruption corresponded to the progressive drainage of most of the shallow part of PdF plumbing system, triggered by a new pulse of deep magma. While erupted magma and high temperature gases were mostly provided by the shallow part of the system, distal sites and summit low temperature fumaroles recorded a deeper triggering mechanism.

  15. Experimental constraints on forecasting the location of volcanic eruptions from pre-eruptive surface deformation

    Science.gov (United States)

    Guldstrand, Frank; Galland, Olivier; Hallot, Erwan; Burchardt, Steffi

    2018-02-01

    Volcanic eruptions pose a threat to lives and property when volcano flanks and surroundings are densely populated. The local impact of an eruption depends firstly on its location, whether it occurs near a volcano summit, or down on the flanks. Then forecasting, with a defined accuracy, the location of a potential, imminent eruption would significantly improve the assessment and mitigation of volcanic hazards. Currently, the conventional volcano monitoring methods based on the analysis of surface deformation assesses whether a volcano may erupt but are not implemented to locate imminent eruptions in real time. Here we show how surface deformation induced by ascending eruptive feeders can be used to forecast the eruption location through a simple geometrical analysis. Our analysis builds on the results of 33 scaled laboratory experiments simulating magma intrusions in a brittle crust, during which the intrusion-induced surface deformation was systematically monitored at high spatial and temporal resolution. In all the experiments, surface deformation preceding the eruptions resulted in systematic uplift, regardless of the intrusion shape. The analysis of the surface deformation patterns leads to the definition of a vector between the centre of the uplifted zone and the point of maximum uplift, which systematically acted as a precursor to the eruption’s location. The temporal evolution of this vector indicated the direction in which the subsequent eruption would occur and ultimately the location itself, irrespective of the feeder shapes. Our findings represent a new approach on how surface deformation on active volcanoes could be analysed and used prior to an eruption with a real potential to improve hazard mitigation.

  16. Guided tooth eruption: Comparison of open and closed eruption techniques in labially impacted maxillary canines

    Directory of Open Access Journals (Sweden)

    S M londhe

    2014-01-01

    Full Text Available Background: After third molars, the maxillary canines are the most commonly impacted permanent teeth and one-third of these are labial impactions. Impacted canines often require orthodontic guidance in the eruption. This study was conducted to assess the posttreatment results of surgically exposed and orthodontically aligned labially impacted maxillary canines comparing two different surgical techniques. Materials and Methods: The study was conducted in two phases, a surgical phase and an orthodontic phase. In surgical phase, events during surgical exposure and recovery of 31 patients with labially impacted maxillary canine were recorded. Patients were managed with open and closed eruption technique. The assessment included comparison of two techniques of surgical exposure, postoperative pain, mobility, vitality, periodontal health, level of impaction, and duration of orthodontic treatment. Results: The postoperative recovery was longer after open eruption than close eruption technique (P = 0.000. Postoperative pain experienced by patients was similar, but regression of pain was faster in closed eruption technique. The mean surgical time for open eruption technique was lesser when compared with closed eruption technique (P = 0.000. The total duration of orthodontic treatment was directly dependent upon the level of impaction, with deeper level of impaction having longer duration of orthodontic treatment. The mobility and vitality of guided canine was similar in both techniques. Conclusion: The closed eruption technique was a longer surgical procedure, but the postoperative pain regression was faster. The duration of orthodontic treatment was longer with deeper level of impaction. The closed eruption surgical techniques provide better periodontal tissues around the guided erupted teeth.

  17. Characterization of volcanic deposits and geoarchaeological studies from the 1815 eruption of Tambora volcano

    Directory of Open Access Journals (Sweden)

    Igan Supriatman Sutawidjaja

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol1no1.20066aThe eruption of Tambora volcano on the island of Sumbawa in 1815 is generally considered as the largest and the most violent volcanic event in recorded history. The cataclysmic eruption occurred on 11 April 1815 was initiated by Plinian eruption type on 5 April and killed more than 90,000 people on Sumbawa and nearby Lombok. The type plinian eruptions occurred twice and ejected gray pumice and ash, to form stratified deposits as thick as 40-150 cm on the slopes and mostly distributed over the district west of the volcano. Following this, at about 7 pm, on 11 April the first pyroclastic surge was generated and progressively became greater extending to almost whole direction, mainly to the north, west, and south districts from the eruption center. The deadliest volcanic eruption buried ancient villages by pyroclastic surge and flow deposits in almost intact state, thus preserving important archaeological evidence for the period. High preservation in relatively stable conditions and known date of the eruptions provide approximate dating for the archaeological remains. Archaeological excavations on the site uncovered a variety of remains were relieved by ground penetrating radar (GPR to map structural remains of the ancient villages under the pyroclastic surge and flow deposits. These traverses showed that GPR could define structures as deep as 10 m (velocity 0.090 m/ns and could accurately map the thickness of the stratified volcanic deposits in the Tambora village area.    

  18. Constraining the dynamics of 2014-15 Bardarbunga-Holuhraun intrusion and eruption using seismic noise

    Science.gov (United States)

    Caudron, Corentin; Donaldson, Clare; White, Robert

    2016-04-01

    The 2010 Eyjafjallajokull volcanic eruption explosively emitted a large quantity of ash in the atmosphere and paralysed the European airspace for weeks. Several seismic scientific studies already contributed to the understanding of this complex eruption (e.g., Tarasewicz et al., 2012). Although an excellent network of seismometers recorded this eruption, some volcanological and seismological aspects are still poorly understood. In order to gain further constraints on the dynamics of this ground-breaking eruptions, we mine the seismic dataset using the seismic ambient noise technique between pairs of stations and the Seismic Amplitude Ratio Analysis (SARA). Our preliminary results reveal a strong contamination of the Cross Correlation Functions (CCF) by the volcanic tremor, particularly above 0.5 Hz even for station pairs located >50 km from the volcano. Although this volcanic tremor precludes the monitoring of the seismic velocities, it literally illuminated the medium. The two phases of the eruptions (i.e., effusive and explosive) are clearly distinguished in these functions due to their different locations. During the explosive phase, an intriguing shift of the main peaks of the cross correlation functions is evidenced (early May 2010). It is remarkably consistent with the downward migration proposed by Tarasewicz et al. (2012) and is interpreted as a migration of the volcanic tremor. SARA methodology, which is continuously imaging and tracking any significant seismicity at a 10-min time scale (Taisne et al., 2010), is applied in the 5-15 Hz frequency band in order to image to continuously migrating microseismicity. The analysis displays several shallow migrations (above 5 km of depth, in March 2010) preceding the effusive phase of the eruption. Interestingly, the results also evidence a fast and deep migration (> 5 km) starting a few hours before the beginning of the explosive phase (13 April 2010). These preliminary results may shed light on the triggering of

  19. Russian eruption warning systems for aviation

    Science.gov (United States)

    Neal, C.; Girina, O.; Senyukov, S.; Rybin, A.; Osiensky, J.; Izbekov, P.; Ferguson, G.

    2009-01-01

    More than 65 potentially active volcanoes on the Kamchatka Peninsula and the Kurile Islands pose a substantial threat to aircraft on the Northern Pacific (NOPAC), Russian Trans-East (RTE), and Pacific Organized Track System (PACOTS) air routes. The Kamchatka Volcanic Eruption Response Team (KVERT) monitors and reports on volcanic hazards to aviation for Kamchatka and the north Kuriles. KVERT scientists utilize real-time seismic data, daily satellite views of the region, real-time video, and pilot and field reports of activity to track and alert the aviation industry of hazardous activity. Most Kurile Island volcanoes are monitored by the Sakhalin Volcanic Eruption Response Team (SVERT) based in Yuzhno-Sakhalinsk. SVERT uses daily moderate resolution imaging spectroradiometer (MODIS) satellite images to look for volcanic activity along this 1,250-km chain of islands. Neither operation is staffed 24 h per day. In addition, the vast majority of Russian volcanoes are not monitored seismically in real-time. Other challenges include multiple time-zones and language differences that hamper communication among volcanologists and meteorologists in the US, Japan, and Russia who share the responsibility to issue official warnings. Rapid, consistent verification of explosive eruptions and determination of cloud heights remain significant technical challenges. Despite these difficulties, in more than a decade of frequent eruptive activity in Kamchatka and the northern Kuriles, no damaging encounters with volcanic ash from Russian eruptions have been recorded. ?? Springer Science+Business Media B.V. 2009.

  20. Large eruption-triggered ocean-island landslide at Tenerife

    DEFF Research Database (Denmark)

    Harris, P; Branney, M; Storey, Michael

    2011-01-01

    An extensive debris-avalanche deposit has been discovered on Cañadas volcano, Tenerife (Canary Islands). The onshore component of the 733 ± 3 ka Abona landslide deposit exposes classic block facies and mixed facies across 90 km2. Three lines of evidence together show that the avalanche was trigge......An extensive debris-avalanche deposit has been discovered on Cañadas volcano, Tenerife (Canary Islands). The onshore component of the 733 ± 3 ka Abona landslide deposit exposes classic block facies and mixed facies across 90 km2. Three lines of evidence together show that the avalanche...... was triggered by an ignimbrite-forming explosive eruption: (1) the deposit is enclosed by phonolitic ignimbrites and is draped by a Plinian fallout layer, all within a single eruption unit; (2) it contains prismatic-jointed pumice blocks that were hot during landslide emplacement, indicated by chilled rims...... and breadcrust surfaces; (3) these blocks yield the same 40Ar/39Ar date as the associated ignimbrite and fall deposit. Landslide hummocks dammed surface water, forming ephemeral lakes perched on the volcano flank. Phonolite dome growth destabilized the southeast sector of a mid-Pleistocene Cañadas caldera wall...

  1. Vaccination elicits a prominent acute phase response in horses.

    Science.gov (United States)

    Andersen, Susanne A; Petersen, Henrik H; Ersbøll, Annette K; Falk-Rønne, Jørgen; Jacobsen, Stine

    2012-02-01

    European and American guidelines for vaccination against tetanus and influenza in horses recommend annual and annual/semi-annual vaccinations, respectively, against the two pathogens. Too-frequent vaccination may, however, have adverse effects, among other things because an inflammatory response is elicited with subsequent alterations in homeostasis. The objective of the study was to compare the acute phase response (APR) in 10 horses following administration of two different types of vaccines, namely, an inactivated Immune Stimulating COMplex (ISCOM) vaccine and a live recombinant vector vaccine. Blood was sampled before and after vaccination to measure levels of serum amyloid A (SAA), fibrinogen, white blood cell counts (WBC) and iron. Vaccination induced a prominent APR with increased WBC, elevated blood levels of SAA and fibrinogen, and decreased serum iron concentrations. The ISCOM vaccine caused significantly (Phorse owners about convalescence after vaccination. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine

    Energy Technology Data Exchange (ETDEWEB)

    Annesley, Thomas M.; Cooks, Robert G.; Herold, David A.; Hoofnagle, Andrew N.

    2016-01-04

    Each year the journal Clinical Chemistry publishes a January special issue on a topic that is relevant to the laboratory medicine community. In January 2016 the topic is mass spectrometry, and the issue is entitled “Clinical Mass Spectrometry: Achieving Prominence in Laboratory Medicine”. One popular feature in our issues is a Q&A on a topic, clearly in this case mass spectrometry. The journal is assembling a panel of 5-6 experts from various areas of mass spectrometry ranging from instrument manufacturing to practicing clinical chemists. Dick Smith is one of the scientist requested to participate in this special issue Q&A on Mass Spectrometry. The Q&A Transcript is attached

  3. The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions

    Directory of Open Access Journals (Sweden)

    M. Toohey

    2011-12-01

    Full Text Available Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year. Sensitivity to eruption season of aerosol optical depth (AOD, clear-sky and all-sky shortwave (SW radiative flux is quantified by first integrating each field for four years after the eruption, then calculating for each cumulative field the absolute or percent difference between the maximum and minimum response from the four eruption seasons. Eruption season has a significant influence on AOD and clear-sky SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~75 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for Pinatubo-magnitude eruption, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to

  4. Three-Dimensional Morphology of a Coronal Prominence Cavity

    Science.gov (United States)

    Gibson, S. E.; Kucera, T. A.; Rastawicki, D.; Dove, J.; deToma, G.; Hao, J.; Hill, S.; Hudson, H. S.; Marque, C.; McIntosh, P. S.; hide

    2010-01-01

    We present a three-dimensional density model of coronal prominence cavities, and a morphological fit that has been tightly constrained by a uniquely well-observed cavity. Observations were obtained as part of an International Heliophysical Year campaign by instruments from a variety of space- and ground-based observatories, spanning wavelengths from radio to soft-X-ray to integrated white light. From these data it is clear that the prominence cavity is the limb manifestation of a longitudinally-extended polar-crown filament channel, and that the cavity is a region of low density relative to the surrounding corona. As a first step towards quantifying density and temperature from campaign spectroscopic data, we establish the three-dimensional morphology of the cavity. This is critical for taking line-of-sight projection effects into account, since cavities are not localized in the plane of the sky and the corona is optically thin. We have augmented a global coronal streamer model to include a tunnel-like cavity with elliptical cross-section and a Gaussian variation of height along the tunnel length. We have developed a semi-automated routine that fits ellipses to cross-sections of the cavity as it rotates past the solar limb, and have applied it to Extreme Ultraviolet Imager (EUVI) observations from the two Solar Terrestrial Relations Observatory (STEREO) spacecraft. This defines the morphological parameters of our model, from which we reproduce forward-modeled cavity observables. We find that cavity morphology and orientation, in combination with the viewpoints of the observing spacecraft, explains the observed variation in cavity visibility for the east vs. west limbs

  5. Postglacial eruptive history and geochemistry of Semisopochnoi volcano, western Aleutian Islands, Alaska

    Science.gov (United States)

    Coombs, Michelle L.; Larsen, Jessica F.; Neal, Christina A.

    2018-02-14

    Semisopochnoi Island, located in the Rat Islands group of the western Aleutian Islands and Aleutian volcanic arc, is a roughly circular island composed of scattered volcanic vents, the prominent caldera of Semisopochnoi volcano, and older, ancestral volcanic rocks. The oldest rocks on the island are gently radially dipping lavas that are the remnants of a shield volcano and of Ragged Top, which is an eroded stratocone southeast of the current caldera. None of these oldest rocks have been dated, but they all are likely Pleistocene in age. Anvil Peak, to the caldera’s north, has the morphology of a young stratocone and is latest Pleistocene to early Holocene in age. The oldest recognized Holocene deposits are those of the caldera-forming eruption, which produced the 7- by 6-km caldera in the center of the island, left nonwelded ignimbrite in valleys below the edifice, and left welded ignimbrite high on its flanks. The caldera-forming eruption produced rocks showing a range of intermediate whole-rock compositions throughout the eruption sequence, although a majority of clasts analyzed form a fairly tight cluster on SiO2-variation diagrams at 62.9 to 63.4 weight percent SiO2. This clustering of compositions at about 63 weight percent SiO2 includes black, dense, obsidian-like clasts, as well as tan, variably oxidized, highly inflated pumice clasts. The best estimate for the timing of the eruption is from a soil dated at 6,920±60 14C years before present underlying a thin facies of the ignimbrite deposit on the island’s north coast. Shortly after the caldera-forming eruption, two scoria cones on the northwest flank of the volcano outside the caldera, Ringworm crater and Threequarter Cone, simultaneously erupted small volumes of andesite.The oldest intracaldera lavas, on the floor of the caldera, are andesitic to dacitic, but are mostly covered by younger lavas and tephras. These intracaldera lavas include the basaltic andesites of small Windy cone, as well as the

  6. Solar eruptions - soil radon - earthquakes

    International Nuclear Information System (INIS)

    Saghatelyan, E.; Petrosyan, L.; Aghbalyan, Yu.; Baburyan, M.; Araratyan, L.

    2004-01-01

    For the first time a new natural phenomenon was established: a contrasting increase in the soil radon level under the influence of solar flares. Such an increase is one of geochemical indicators of earthquakes. Most researchers consider this a phenomenon of exclusively terrestrial processes. Investigations regarding the link of earthquakes to solar activity carried out during the last decade in different countries are based on the analysis of statistical data ΣΕ (t) and W (t). As established, the overall seismicity of the Earth and its separate regions depends of an 11-year long cycle of solar activity. Data provided in the paper based on experimental studies serve the first step on the way of experimental data on revealing cause-and-reason solar-terrestrials bonds in a series s olar eruption-lithosphere radon-earthquakes . They need further collection of experimental data. For the first time, through radon constituent of terrestrial radiation objectification has been made of elementary lattice of the Hartmann's network contoured out by bio location method. As found out, radon concentration variations in Hartmann's network nodes determine the dynamics of solar-terrestrial relationships. Of the three types of rapidly running processes conditioned by solar-terrestrial bonds earthquakes are attributed to rapidly running destructive processes that occur in the most intense way at the juncture of tectonic massifs, along transformed and deep failures. The basic factors provoking the earthquakes are both magnetic-structural effects and a long-term (over 5 months) bombing of the surface of lithosphere by highly energetic particles of corpuscular solar flows, this being approved by photometry. As a result of solar flares that occurred from 29 October to 4 November 2003, a sharply contrasting increase in soil radon was established which is an earthquake indicator on the territory of Yerevan City. A month and a half later, earthquakes occurred in San-Francisco, Iran, Turkey

  7. Tidal Control of Jet Eruptions on Enceladus as Observed by Cassini ISS between 2005 and 2007

    Science.gov (United States)

    Hurford, T. A.; Helfenstein, P.; Spitale, J. N.

    2012-01-01

    Observations of Enceladus have revealed active jets of material erupting from cracks on its south polar surface. It has previously been proposed that diurnal tidal stress, driven by Enceladus' orbital eccentricity, may actively produce surface movement along these cracks daily and thus may regulate when eruptions occur. Our analysis of the stress on jet source regions identified in Cassini ISS images reveals tidal stress as a plausible controlling mechanism of jet activity. However, the evidence available in the published and preliminary observations of jet activity between 2005 and 2007 may not be able to solidify the link between tidal stress and eruptions from fissures. Ongoing, far more comprehensive analyses based on recent, much higher resolution jetting observations have the potential to prove otherwise.

  8. Tranexamic acid-induced fixed drug eruption

    Directory of Open Access Journals (Sweden)

    Natsuko Matsumura

    2015-01-01

    Full Text Available A 33-year-old male showed multiple pigmented patches on his trunk and extremities after he took tranexamic acid for common cold. He stated that similar eruptions appeared when he was treated with tranexamic acid for influenza 10 months before. Patch test showed positive results at 48 h and 72 h by 1% and 10% tranexamic acid at the lesional skin only. To our knowledge, nine cases of fixed drug eruption induced by tranexamic acid have been reported in Japan. Tranexamic acid is a safe drug and frequently used because of its anti-fibrinolytic and anti-inflammatory effects, but caution of inducing fixed drug eruption should be necessary.

  9. Pattern of drug eruptions in a tertiary care hospital

    International Nuclear Information System (INIS)

    Tahir, Z.; Nadeem, N.; Aman, S.; Kazmi, A.H.

    2013-01-01

    Background: An adverse drug reaction is unintentional which occurs at doses used for prophylaxis, diagnosis or treatment. Objectives: To determine the frequency of various cutaneous drug eruptions that occur in patients in a tertiary care hospital setting. Patients and Methods: All patients with cutaneous drug eruptions seen at the Dermatology Department of Mayo Hospital, Lahore, over 6 months were enrolled and the pattern of drug eruptions like urticaria, angioedema, fixed drug eruption, maculopapular rash, erythema multiforme, Stevens-Johnson syndrome and toxic epidermal necrolysis etc. were recorded, along with drugs that caused it. Results:A total of 160 patients (86 males, 74 females) were included in the study. Mean age of patients was 30.7+-15.4 years. Major eruptions were fixed drug eruption (21.3%) followed by urticaria without angioedema (10%), maculopapular rash (9.3%), lichenoid drug eruption (8.7%), acneiform drug eruption (7.5%), Stevens-Johnson syndrome (6.9%), vesiculobullous eruption (5.6%), erythema multiforme and eczematous eruption (5% each). Common drugs causing eruptions were sulfonamides (16.3%), followed by NSAIDs (14.4%), herbal and homeopathic medications (12.5%), penicillins (9.3%), tetracyclines (8.7%), antituberculous drugs, cephalosporins and antiepileptics (6.3% each). Conclusion: Fixed drug eruption and urticaria without angioedema were commonest eruptions while, sulfonamides and NSAIDs were the major causative drugs. Policy message: Reporting of adverse drug reactions is not done in Pakistan and needs to be done in each hospital. (author)

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

    Science.gov (United States)

    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.

  11. Crystallization Conditions at Cascade and Other Arc Volcanoes: The Role of Recharge, and Ultimate, Proximal and Immediate Causes of Eruption

    Science.gov (United States)

    Putirka, K. D.

    2016-12-01

    A number of hypotheses have been offered to explain why volcanoes erupt. These include magma mixing, mafic recharge, or partial crystallization, any of which can drive parts or all of a system to vapor saturation, and so add to a magma's buoyancy. Age dates indicate long pre-eruption storage times for felsic magmas erupted at arcs, indicating that mafic recharge magmas, which can reinvigorate such systems, is a possible eruption trigger. However, plutonic systems reveal numerous recharge events that have no obvious ties to eruption (Coint et al. 2013; Putirka et al. 2014). And crystallization conditions at some arc systems support the implicit view, that recharge might be a necessary, but not a sufficient condition for eruption. At several Cascade volcanoes, Cpx and Amp crystals record coolings of 100-300oC. The Cpx grains derive exclusively from mafic enclaves, while Amp grains derive from both host and enclave materials. These considerable coolings call for a time lag following recharge, and indicate that vapor saturation is a proximal, although not necessarily an immediate cause of eruption. But we cannot discount recharge altogether. At the Cascades and at other arcs, Cpx crystalizes throughout the middle and upper crust, mostly from the surface down to 15 km. And high Fo olivine grains provide evidence for very hot magmas that intrude the upper mantle and lower crust, and possibly the middle crust, if hydrous. Volcanic pathways thus clearly extend into the middle crust, and at times, well below the Moho. It is unclear to what extent these deep pathways are hydraulically connected to the surface, or the role of deep-seated processes in initiating or sustaining eruptions. Progress in understanding these pathways, and triggering mechanisms, requires our differentiating "ultimate", "proximal" and "immediate" causes, and determining which of various magmatic processes provide necessary or sufficient conditions for eruption.

  12. Eruptions and superhumps in dwarf novae

    International Nuclear Information System (INIS)

    Patterson, J.

    1979-01-01

    The existence of two distinct eruption types in dwarf novae is considered. A small subclass of dwarf novae, the SU Ursae Majoris stars, show occasional very bright and long eruptions (''supermaxima''), and during supermaxima, large-amplitude photometric variations (''superhumps'') at a period related to the orbital period are seen. Two new stars showing these effects, AY Lyrae and YZ Cancri, are reported. A third star, WZ Sagittae, is probably also a member of the class. Models for the superhumps are reviewed and found to be unsatisfactory. Observational constraints on a successful model are discussed

  13. Global science: the eruption of Krakatau.

    Science.gov (United States)

    Dörries, Matthias

    2003-01-01

    The eruption of the volcano Krakatau in the Netherlands East Indies (Indonesia) in 1883 had worldwide impact. This was perceived in the three quite different types of global propagation that occurred after the eruption: a rapid pressure wave, noticeable only to measuring instruments, followed a few hours later by the spread of the news of the event, succeeded by a slowly expanding optical phenomenon that lasted for a couple of years. Krakatau was the first natural catastrophe of global magnitude that was almost immediately recognized as such throughout the world, largely thanks to the recently installed worldwide telegraphic network.

  14. Terbinafine-induced lichenoid drug eruption.

    Science.gov (United States)

    Zheng, Yue; Zhang, Jie; Chen, Haiyan; Lai, Wei; Maibach, Howard I

    2017-03-01

    Drug-induced lichen planus has been induced by antibiotics, anticonvulsants, antidiabetics, antimalarials, antitubercular drugs, antihypertensives, psychiatric drugs, chemotherapeutic agents, diuretic, heavy metals, NSAIDs, etc. Terbinafine, an antifungal agent, is widely used for dermatophyte infections and onychomycosis. Cutaneous adverse effects of terbinafine are rarely reported. Here, we report a case of terbinafine-induced lichenoid drug eruption in a 22-year-old who presented with generalized lichenoid eruption 2 weeks after terbinafine initiation of. The body and lip cleared completely after 8 weeks of drug withdrawal; nail change cleared after 12 weeks.

  15. The Variable Climate Impact of Volcanic Eruptions

    Science.gov (United States)

    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

  16. Asymptomatic petechial eruption on the lower legs.

    Science.gov (United States)

    Mendese, Gary; Grande, Donald

    2013-09-01

    The authors report an unusual case of Rocky Mountain spotted fever that presented as an asymptomatic petechial eruption on the lower legs. Rocky Mountain spotted fever is rare in New England and, as such, is typically not on the differential diagnosis when presented with such patients. What began as an asymptomatic eruption progressed to more classic signs of the disease, including a positive Rocky Mountain spotted fever titer. The patient was successfully treated with doxycydine and within a short period of time, was completely back at baseline.

  17. Clinico-Epidemiological Comparison of Delusion-Prominent and Hallucination-Prominent Clinical Subgroups of Paranoid Schizophrenia.

    Science.gov (United States)

    Kreinin, Anatoly; Krishtul, Vladimir; Kirsh, Zvi; Menuchin, Michael

    2015-01-01

    Though hallucinations and delusions are prominent basic impairments in schizophrenia, reports of the relationship between hallucinatory and delusional symptoms among schizophrenia patients are scant. To examine the epidemiological and clinical differences between mainly hallucinatory and mainly delusional subgroups of paranoid schizophrenia patients. One hundred schizophrenia patients, paranoid type, were recruited. In a cross-sectional study, participants were divided into Mainly Hallucinatory (H) and Mainly Delusional (D) subgroups. Demographic variables were compared and clinical characteristics were evaluated using the Scale for the Assessment of Positive Symptoms, the Scale for the Assessment of Negative Symptoms, and the Clinical Global Impression Scale. The Quality-of-Life Enjoyment and Satisfaction Questionnaire-18 was used to assess quality of life. Clinically, the H group was more heterogeneous as expressed by the broader range of scores that described the clinical picture of patients in that subgroup (in 43 of 78 variables, 55.13%) and similar ranges of scores (31 of 78 variables, 39.74%) for patients in the D group. Duration of hospitalization was significantly longer in group H than in group D (p=0.047). There was no statistically significant difference between the H and D subgroups in demographic characteristics. There are distinct epidemiological and clinical differences between the H and D subgroups, with more severe positive and negative symptoms and greater functional impairment in the H group. Paranoid schizophrenia patients with prominent hallucinations have poorer prognosis and need intensive therapeutic rehabilitation beginning with onset-of-illness. Further genetic studies and comparisons of fMRI and/or PET findings are warranted to investigate additional distinctive characteristics of these subgroups.

  18. The frequency of explosive volcanic eruptions in Southeast Asia.

    Science.gov (United States)

    Whelley, Patrick L; Newhall, Christopher G; Bradley, Kyle E

    There are ~750 active and potentially active volcanoes in Southeast Asia. Ash from eruptions of volcanic explosivity index 3 (VEI 3) and smaller pose mostly local hazards while eruptions of VEI ≥ 4 could disrupt trade, travel, and daily life in large parts of the region. We classify Southeast Asian volcanoes into five groups, using their morphology and, where known, their eruptive history and degassing style. Because the eruptive histories of most volcanoes in Southeast Asia are poorly constrained, we assume that volcanoes with similar morphologies have had similar eruption histories. Eruption histories of well-studied examples of each morphologic class serve as proxy histories for understudied volcanoes in the class. From known and proxy eruptive histories, we estimate that decadal probabilities of VEI 4-8 eruptions in Southeast Asia are nearly 1.0, ~0.6, ~0.15, ~0.012, and ~0.001, respectively.

  19. Impacts of a Pinatubo-size volcanic eruption on ENSO

    KAUST Repository

    Predybaylo, Evgeniya; Stenchikov, Georgiy L.; Wittenberg, Andrew T.; Zeng, Fanrong

    2017-01-01

    Observations and model simulations of the climate responses to strong explosive low-latitude volcanic eruptions suggest a significant increase in the likelihood of El Niño during the eruption and posteruption years, though model results have been

  20. Holocene eruption history in Iceland - Eruption frequency vs. Tephra layer frequency

    Science.gov (United States)

    Oladottir, B. A.; Larsen, G.

    2012-12-01

    Volcanic deposits of all kinds are used to reconstruct eruption history of volcanoes and volcanic zones. In Iceland tephra is the ideal volcanic deposit to study eruption history as two out of every three eruptions taking place there during the last 11 centuries have been explosive, leaving tephra as their only product. If eruptions producing both lava and tephra are included three out of every four eruptions have produced tephra. Tephra dispersal and deposition depends on factors such as eruption magnitude, eruption cloud height, duration of eruption and prevailing wind directions at the time of eruption. Several outcrops around a particular volcano must therefore be measured to obtain optimal information of its eruption history. Vegetation in the area of deposition is also of great importance for its preservation. Tephra deposited on un-vegetated land is rapidly eroded by wind and water, and deposits up to few tens of cm thickness may be lost from the record. Such tephra deposited on grassy or forested land is at least partly sheltered from the wind after deposition. Soon after tephra deposition (how soon depends on tephra thickness) the root system of the vegetation creates an even better shelter for the tephra and when this stage is reached the tephra is preserved in the soil for millennia, given that no soil erosion takes place. Vegetation is often boosted in the first years after tephra deposition which in turn helps tephra preservation. A setback of using soil sections for reconstructing Holocene eruption history is the lack of soil at the beginning of the era but for that time period tephra records in lake and marine sediments can be used. When tephra stratigraphy in soil sections is measured to study eruption history and eruption frequency of a volcano it must be kept in mind that what is seen is in fact the tephra layer frequency. One section only shows tephra layers deposited in that location and more importantly only the layers preserved there. The

  1. Origin and structures of solar eruptions II: Magnetic modeling

    Science.gov (United States)

    Guo, Yang; Cheng, Xin; Ding, MingDe

    2017-07-01

    The topology and dynamics of the three-dimensional magnetic field in the solar atmosphere govern various solar eruptive phenomena and activities, such as flares, coronal mass ejections, and filaments/prominences. We have to observe and model the vector magnetic field to understand the structures and physical mechanisms of these solar activities. Vector magnetic fields on the photosphere are routinely observed via the polarized light, and inferred with the inversion of Stokes profiles. To analyze these vector magnetic fields, we need first to remove the 180° ambiguity of the transverse components and correct the projection effect. Then, the vector magnetic field can be served as the boundary conditions for a force-free field modeling after a proper preprocessing. The photospheric velocity field can also be derived from a time sequence of vector magnetic fields. Three-dimensional magnetic field could be derived and studied with theoretical force-free field models, numerical nonlinear force-free field models, magnetohydrostatic models, and magnetohydrodynamic models. Magnetic energy can be computed with three-dimensional magnetic field models or a time series of vector magnetic field. The magnetic topology is analyzed by pinpointing the positions of magnetic null points, bald patches, and quasi-separatrix layers. As a well conserved physical quantity, magnetic helicity can be computed with various methods, such as the finite volume method, discrete flux tube method, and helicity flux integration method. This quantity serves as a promising parameter characterizing the activity level of solar active regions.

  2. Social and environmental impact of volcaniclastic flows related to 472 AD eruption at Vesuvius from stratigraphic and geoarcheological data

    Science.gov (United States)

    Di Vito, Mauro A.; de Vita, Sandro; Rucco, Ilaria; Bini, Monica; Zanchetta, Giovanni; Aurino, Paola; Cesarano, Mario; Ebanista, Carlo; Rosi, Mauro; Ricciardi, Giovanni

    2017-04-01

    There is a growing number of evidences in the surrounding plain of Somma-Vesuvius volcano which indicate that along with primary volcanic processes (i.e. fallout, pyroclastic density currents) the syn-eruptive and post-eruptive volcaniclastic remobilization has severely impacted the ancient civilizations, which flourished in the area. This represents an important starting point for understanding the future hazard related to a potential (and not remote) renewal of volcanic activity of the Campaniana volcanoes. We present geoarcheological and stratigraphic data obtained from the analysis of more than 160 sections in the Campanian plain showing the widespread impact of volcaniclastic debris flows and floods originated from the rapid remobilization of the products of the AD 472 eruption of Somma-Vesuvius, both on the environment and on the human landscape. This eruption was one of the two sub-Plinian historical events of Somma Vesuvius. This event largely impacted the northern and eastern territory surrounding the volcano with deposition of a complex sequence of pyroclastic-fallout and -current deposits. These sequences were variably affected by syn- and post-eruptive mobilization both along the Somma-Vesuvius slopes and the Apennine valleys with the emplacement of thick mud- and debris-flows which strongly modified the preexisting paleogeography of the Plain with irretrievable damages to the agricultural and urban landscape. The multidisciplinary approach to the study of the sequences permitted to reconstruct the palaeoenvironment before the eruption and the timing of the emplacement of both pyroclastic and volcanoclastic deposits. The preexisting landscape was characterized by intense human occupation, although showing strong evidences of degradation and abandonment due to the progressive decline of the Roman Empire. The impact of volcaniclastic flows continued for decades after the eruption as highlighted in the studied sequences by stratigraphic and archaeologic

  3. Prominent string of galaxies in Bootes: evidence for a Lagrangian singularity

    Energy Technology Data Exchange (ETDEWEB)

    Tago, E; Einasto, J; Saar, E

    1986-01-15

    An outstanding string of galaxies and of small groups in Bootes has been found during a study of bridges between the Coma and the Local superclusters. It lies on the boundary of a large void between the Hercules and the Local superclusters, has a length of 50 Mpc, is only a few megaparsecs wide and consists of non-elliptical galaxies. A possible explanation by a specific Lagrangian singularity at the formation, the imprint of which has survived in the present galaxy distribution, is proposed. (author).

  4. Evidence of a prominent genetic basis for associations between psychoneurometric traits and common mental disorders.

    Science.gov (United States)

    Venables, Noah C; Hicks, Brian M; Yancey, James R; Kramer, Mark D; Nelson, Lindsay D; Strickland, Casey M; Krueger, Robert F; Iacono, William G; Patrick, Christopher J

    2017-05-01

    Threat sensitivity (THT) and weak inhibitory control (or disinhibition; DIS) are trait constructs that relate to multiple types of psychopathology and can be assessed psychoneurometrically (i.e., using self-report and physiological indicators combined). However, to establish that psychoneurometric assessments of THT and DIS index biologically-based liabilities, it is important to clarify the etiologic bases of these variables and their associations with clinical problems. The current work addressed this important issue using data from a sample of identical and fraternal adult twins (N=454). THT was quantified using a scale measure and three physiological indicators of emotional reactivity to visual aversive stimuli. DIS was operationalized using scores on two scale measures combined with two brain indicators from cognitive processing tasks. THT and DIS operationalized in these ways both showed appreciable heritability (0.45, 0.68), and genetic variance in these traits accounted for most of their phenotypic associations with fear, distress, and substance use disorder symptoms. Our findings suggest that, as indices of basic dispositional liabilities for multiple forms of psychopathology with direct links to neurophysiology, psychoneurometric assessments of THT and DIS represent novel and important targets for biologically-oriented research on psychopathology. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. No evidence for shallow shear motion on the Mat Fault, a prominent ...

    Indian Academy of Sciences (India)

    3Department of Geography & Resource Management, Mizoram University, Aizawl 796 004, India. 4Department of ..... internal deformation adjacent to southeast Asia and western Pacific; J. ... earthquake; Geomatics, Natural Hazards and Risk 2. 325–328. Gahalaut V K and Arora B R 2012 Structural control on along-strike ...

  6. No evidence for shallow shear motion on the Mat Fault, a prominent ...

    Indian Academy of Sciences (India)

    and is flanked by the Bay of Bengal sediments to the west and Shan Plateau to the east (Fitch 1972;. Le Dain et al. ... Shan Plateau and joins into the Andaman sea rift system which finally joins the Sumatra Fault. System in ..... 2008 Subduction of the Indian lithosphere beneath the. Tibetan Plateau and Burma; Earth Planet.

  7. Sulphur-rich volcanic eruptions and stratospheric aerosols

    Science.gov (United States)

    Rampino, M. R.; Self, S.

    1984-01-01

    Data from direct measurements of stratospheric optical depth, Greenland ice-core acidity, and volcanological studies are compared, and it is shown that relatively small but sulfur-rich volcanic eruptions can have atmospheric effects equal to or even greater than much larger sulfur-poor eruptions. These small eruptions are probably the most frequent cause of increased stratospheric aerosols. The possible sources of the excess sulfur released in these eruptions are discussed.

  8. New Perspectives on the Climatic Impact of the 1600 Eruption of Huaynaputina Volcano, Peru

    Science.gov (United States)

    Verosub, K. L.; Lippman, J.

    2007-05-01

    A critical test of the new understanding of volcanic aerosols developed since 1982 is to determine if it can predict the effects of larger eruptions than those that have occurred since El Chichon. To do that, requires detailed information about the effects of specific large eruptions. We have been investigating the human and climatic impacts of the 1600 eruption of Huaynaputina volcano in Peru. The estimated Volcanic Explosivity Index for this eruption is 6, which is comparable to that of the 1815 eruption of Tambora volcano in Indonesia, which produced global cooling and led to crop failures, famine and social unrest. On the basis of tree-ring data, Briffa et al. (1998) suggested that the most severe short-term Northern Hemisphere cooling event of the past 600 years occurred in 1601, the year following the Huaynaputina eruption. In order gain a better understanding of the nature and extent of this cooling, we have been collecting annual time series that provide information about climatic conditions during time intervals that bracket the Huaynaputina eruption. Among the time series that we have examined (or plan to examine) are ice conditions in the harbors of Tallinn, Estonia, and Riga, Latvia and in Lake Suwa in Japan: cherry blossom blooming (sakura) dates from Kyoto, Japan; records of agricultural production from China and Russia; tithe records from the Spanish colonial empire; dates of the beginning of the wine harvest in France and the rye harvest in Sweden; prices of agricultural commodities in Europe; and river flows from the Nile and the Colorado. Often, in the records we have examined, 1601 shows up as one of the coldest years, if not the coldest year. In addition, the worst famines in Russian history took place between 1601 and 1603, which eventually led to the overthrow of Tsar Boris Gudonov. Thus, there is considerable evidence that the climatic impacts of the Huaynaputina eruption were comparable to those from the Tambora eruption. This result is

  9. The eruption of Mount Pagan volcano, Mariana Islands, 15 May 1981

    Science.gov (United States)

    Banks, N.G.; Koyanagi, R.Y.; Sinton, J.M.; Honma, K.T.

    1984-01-01

    A major explosive eruption occurred 15 May 1981 at Mount Pagan Volcano, the larger of two historic eruptive centers on Pagan Island, Mariana Islands. The eruption was preceded by increased numbers of locally felt earthquakes beginning in late March or early April and by new ground cracks, new sublimates, and increased gas emissions. A swarm of felt earthquakes began at 0745h (local time = UCT+10 hours) 15 May, and at 0915 h, closely following a loud sonic boom, a strong plinian column issued from the volcano. The high-altitude ash cloud (at least 13.5 km) travelled south-southeast, but ash and scoria deposits were thickest (> 2 m) in the NW sector of the island because of the prevailing low-altitude southeasterly winds. The early activity of 15 May probably involved magmatic eruption along a fissure system oriented about N10??E. However, the eruption became hydromagmatic, possibly within minutes, and was largely restricted to three long-lived vents. The northernmost of these built a substantial new scoria-ash cinder cone. Flows and air-fall deposits, consisting almost entirely of juvenile material, exceeded 105 ?? 106 m3 in volume (75 ?? 106 m3 of magma) on land and at least 70-100 ?? 606 m3 at sea. An unknown volume was carried away by stratospheric winds. Lithic blocks and juvenile bombs as large as 1 m in diameter were thrown more than 2 km from the summit, and evidence for base-surge was observed in restricted corridors as low as 200 m elevation on the north and south slopes of the volcano. Neither of these events resulted in serious injuries to the 54 residents of the island, nor did the eruption produce serious chemical hazards in their water supply. Weak eruptions occurred during the ensuing month, and some of these were monitored by ground observations, seismic monitoring, and deformation studies. Precursory seismicity and possibly deformation occurred with some of the observed eruptions. More vigorous eruptions were reported by visiting residents in late

  10. Radiologic comparison of erosive polyarthritis with prominent interphalangeal involvement

    International Nuclear Information System (INIS)

    Gold, R.H.; Bassett, L.W.; Theros, E.G.

    1982-01-01

    Psoriatic arthritis, Reiter's disease, and multicentric reticulohistiocytosis may manifest prominent interphalangeal joint and cutaneous involvement. All three disorders may also affect the sacroiliac joints and spine. Despite these similarities, there are basic radiologic differences enabling distinction between the three disorders. Erosive osteoarthritis must also be considered in the differential diagnosis of interphalangeal erosive arthritis. Psoriatic erosions are characteristically ill defined, often bilaterally asymmetrical, usually unaccompanied by significant osteoporosis, and frequently associated with florid proliferation of subperiosteal new bone. An unilateral polyarticular pattern, which often occurs in a single ray, is the most prevalent of several patterns of involvement. Reiter's disease exhibits many clinical and radiologic similarities to psoriatic arthritis, but in the former there tends to be selective involvement of the joints of the lower limbs and particularly the feet, with relative sparing of the hands and wrists, while in the latter the joints of the upper and lower limbs tend to be involved to an equal extent. Multicentric reticulohistiocytosis (MR). Lesions predominate in skin and synovium and result in sharply circumscribed, rapidly progressive, strikingly bilaterally symmetrical erosions spreading from joint margins to articular surfaces. Most or all of the diarthrodial joints may be affected, but interphalangeal joint predominance and early and severe atlanto-axial involvement are characteristic. Erosive osteoarthritis is characterized by interphalangeal subchondral erosions, accompanying periosteal new bone that is more subtle than that of psoriatic arthritis, and interphalangeal bony ankylosis that occurs with the same frequency as that of psoriatic arthritis. (orig.)

  11. Quantifying the cepstral peak prominence, a measure of dysphonia.

    Science.gov (United States)

    Heman-Ackah, Yolanda D; Sataloff, Robert T; Laureyns, Griet; Lurie, Deborah; Michael, Deirdre D; Heuer, Reinhardt; Rubin, Adam; Eller, Robert; Chandran, Swapna; Abaza, Mona; Lyons, Karen; Divi, Venu; Lott, Joanna; Johnson, Jennifer; Hillenbrand, James

    2014-11-01

    The purpose of this study is to establish normative values for the smoothed cepstral peak prominence (CPPS) and its sensitivity and specificity as a measure of dysphonia. Prospective cohort study. Voice samples of running speech were obtained from 835 patients and 50 volunteers. Eight laryngologists and four speech-language pathologists performed perceptual ratings of the voice samples on the degree of dysphonia/normality using an analog scale. The mean of their perceptual ratings was used as the gold standard for the detection of the presence or absence of dysphonia. CPPS was measured using the CPPS algorithm of Hillenbrand, and the cut-off value for positivity that has the highest sensitivity and specificity for discriminating between normal and severely dysphonia voices was determined based on ROC-curve analysis. The cut-off value for normal for CPPS was set at 4.0 or higher, which gave a sensitivity of 92.4%, a specificity of 79%, a positive predictive value of 82.5%, and a negative predictive value of 90.8%. The area under the receiver operating characteristic (ROC) curve was 0.937 (P dysphonia, with the normal value of CPPS (Hillenbrand algorithm) of a running speech sample being defined as a value of 4.0 or higher. Copyright © 2014 The Voice Foundation. All rights reserved.

  12. Porcine CD38 exhibits prominent secondary NAD(+) cyclase activity.

    Science.gov (United States)

    Ting, Kai Yiu; Leung, Christina F P; Graeff, Richard M; Lee, Hon Cheung; Hao, Quan; Kotaka, Masayo

    2016-03-01

    Cyclic ADP-ribose (cADPR) mobilizes intracellular Ca(2+) stores and activates Ca(2+) influx to regulate a wide range of physiological processes. It is one of the products produced from the catalysis of NAD(+) by the multifunctional CD38/ADP-ribosyl cyclase superfamily. After elimination of the nicotinamide ring by the enzyme, the reaction intermediate of NAD(+) can either be hydrolyzed to form linear ADPR or cyclized to form cADPR. We have previously shown that human CD38 exhibits a higher preference towards the hydrolysis of NAD(+) to form linear ADPR while Aplysia ADP-ribosyl cyclase prefers cyclizing NAD(+) to form cADPR. In this study, we characterized the enzymatic properties of porcine CD38 and revealed that it has a prominent secondary NAD(+) cyclase activity producing cADPR. We also determined the X-ray crystallographic structures of porcine CD38 and were able to observe conformational flexibility at the base of the active site of the enzyme which allow the NAD(+) reaction intermediate to adopt conformations resulting in both hydrolysis and cyclization forming linear ADPR and cADPR respectively. © 2016 The Protein Society.

  13. Prominent feature extraction for review analysis: an empirical study

    Science.gov (United States)

    Agarwal, Basant; Mittal, Namita

    2016-05-01

    Sentiment analysis (SA) research has increased tremendously in recent times. SA aims to determine the sentiment orientation of a given text into positive or negative polarity. Motivation for SA research is the need for the industry to know the opinion of the users about their product from online portals, blogs, discussion boards and reviews and so on. Efficient features need to be extracted for machine-learning algorithm for better sentiment classification. In this paper, initially various features are extracted such as unigrams, bi-grams and dependency features from the text. In addition, new bi-tagged features are also extracted that conform to predefined part-of-speech patterns. Furthermore, various composite features are created using these features. Information gain (IG) and minimum redundancy maximum relevancy (mRMR) feature selection methods are used to eliminate the noisy and irrelevant features from the feature vector. Finally, machine-learning algorithms are used for classifying the review document into positive or negative class. Effects of different categories of features are investigated on four standard data-sets, namely, movie review and product (book, DVD and electronics) review data-sets. Experimental results show that composite features created from prominent features of unigram and bi-tagged features perform better than other features for sentiment classification. mRMR is a better feature selection method as compared with IG for sentiment classification. Boolean Multinomial Naïve Bayes) algorithm performs better than support vector machine classifier for SA in terms of accuracy and execution time.

  14. The coordination of boundary tones and its interaction with prominence.

    Science.gov (United States)

    Katsika, Argyro; Krivokapić, Jelena; Mooshammer, Christine; Tiede, Mark; Goldstein, Louis

    2014-05-01

    This study investigates the coordination of boundary tones as a function of stress and pitch accent. Boundary tone coordination has not been experimentally investigated previously, and the effect of prominence on this coordination, and whether it is lexical (stress-driven) or phrasal (pitch accent-driven) in nature is unclear. We assess these issues using a variety of syntactic constructions to elicit different boundary tones in an Electromagnetic Articulography (EMA) study of Greek. The results indicate that the onset of boundary tones co-occurs with the articulatory target of the final vowel. This timing is further modified by stress, but not by pitch accent: boundary tones are initiated earlier in words with non-final stress than in words with final stress regardless of accentual status. Visual data inspection reveals that phrase-final words are followed by acoustic pauses during which specific articulatory postures occur. Additional analyses show that these postures reach their achievement point at a stable temporal distance from boundary tone onsets regardless of stress position. Based on these results and parallel findings on boundary lengthening reported elsewhere, a novel approach to prosody is proposed within the context of Articulatory Phonology: rather than seeing prosodic (lexical and phrasal) events as independent entities, a set of coordination relations between them is suggested. The implications of this account for prosodic architecture are discussed.

  15. Prominent Determinants of Consumer-Based Brand Equity

    Directory of Open Access Journals (Sweden)

    Elisa Battistoni

    2013-08-01

    Full Text Available In this paper we investigate the most prominent drivers of brand equity, from a consumerbased point of view. We present a new approach for measuring brand equity, which can be applied regardless of the brand sector and is based on the Analytic Hierarchy Process. This approach has the main advantage of allowing for comparisons to be made between non‐directly measurable elements and also has the advantage of enabling the ranking of intangible criteria, such as consumers’ feelings or purchase intentions. We focus on the fashion industry, since we believe in the higher value of our approach when applied to brands which offer products with less tangible characteristics. Thanks to a case study – which involved about 250 interviewees – we succeed in finding and prioritizing the elements which can have an impact on the brand value. We also provide a global ranking for three apparel brands: Gap, H&M and Zara. The results from our model are consistent with other popular ratings and can be extremely useful for brand managers.

  16. CME Eruption Onset Observations from EIT and SXT

    Science.gov (United States)

    Sterling, A. C.

    2004-01-01

    Why CMEs erupt is a major outstanding puzzle of solar physics. Signatures observable at the earliest stages of eruption onset may hold precious clues about the onset mechanism. We present observations in EUV from SOHO/EIT and in soft X-rays from Yohkoh/SXT of the re-eruption and eruption phases of CME expulsion, along with the eruption's magnetic setting found from SOHO/MDI magnetograms. Most of our events involve clearly-observable filament eruptions and multiple neutral lines, and we use the magnetic settings and motions of the filaments to help infer the geometry and behavior of the associated erupting magnetic fields. Pre-eruption and early-eruption signatures include a relatively slow filament rise prior to eruption, and intensity "dimmings" and brightenings, both in the immediate neighborhood of the "core" (location of greatest magnetic shear) of the erupting fields and at locations remote from the core. These signatures and their relative timings place observational constraints on eruption mechanisms; our recent work has focused on implications for the so-called "tether cutting" and "breakout" models, but the same observational constraints are applicable to any model.

  17. Robust satellite techniques for monitoring volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Pergola, N.; Pietrapertosa, C. [Consiglio Nazionale delle Ricerche, Istituto di Metodologie Avanzate, Tito Scalo, PZ (Italy); Lacava, T.; Tramutoli, V. [Potenza Universita' della Basilicata, Potenza (Italy). Dipt. di Ingegneria e Fisica dell' Ambiente

    2001-04-01

    Through this paper the robust approach to monitoring volcanic aerosols by satellite is applied to an extended set of events affecting Stromboli and Etna volcanoes to assess its performance in automated detection of eruptive clouds and in monitoring pre-eruptive emission activities. Using only NOAA/AVHRR data at hand (without any specific atmospheric model or ancillary ground-based measurements) the proposed method automatically discriminates meteorological from eruptive volcanic clouds and, in several cases, identified pre-eruptive anomalies in the emission rates not identified by traditional methods. The main merit of this approach is its effectiveness in recognising field anomalies also in the presence of a highly variable surface background as well as its intrinsic exportability not only on different geographic areas but also on different satellite instrumental packages. In particular, the possibility to extend the proposed method to the incoming new MSG/SEVIRI satellite package (which is going to fly next year) with its improved spectral (specific bands for SO{sub 2}) and temporal (up to 15 min) resolutions has been evaluated representing the natural continuation of this work.

  18. Giant Plagioclase Basalts, eruption rate versus time

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging) 1461 1996 Oct 15 13:05:22

    I found the GPB lavas to be very interest- ing because in some ... by Venkatesan et al (1993) and thus in a way validates my approach. ... and age calculation of lavas from phenocrysts. Keywords. Deccan Trap; Giant Plagioclase Basalts; eruption duration. Proc. Indian Acad. Sci. (Earth Planet. Sci.), 111, No. 4, December ...

  19. Guidance of eruption for general practitioners.

    Science.gov (United States)

    Ngan, Peter W; Kao, Elizabeth C; Wei, Stephen H

    2003-04-01

    The principle of early treatment through well-planned extraction of primary teeth followed by removal of permanent teeth has stood the test of time. The objective of this article is to develop some simple guidelines for general dental practitioners to perform 'guidance of eruption' in malocclusion with severe crowding.

  20. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Coronal holes and interplanetary disturbances are important aspects of the physics of the Sun and heliosphere. Interplanetary disturbances are identified as an increase in the density turbulence compared with the ambient solar wind. Erupting stream disturbances are transient large-scale structures of ...

  1. Bi-decadal variability excited in the coupled ocean-atmosphere system by strong tropical volcanic eruptions

    Energy Technology Data Exchange (ETDEWEB)

    Zanchettin, D.; Lorenz, S.; Lohmann, K.; Jungclaus, J.H. [Max Planck Institute for Meteorology, Ocean in the Earth System Department, Hamburg (Germany); Timmreck, C. [Max Planck Institute for Meteorology, Atmosphere in the Earth System Department, Hamburg (Germany); Graf, H.-F. [University of Cambridge, Centre for Atmospheric Science, Cambridge (United Kingdom); Rubino, A. [Ca' Foscari University, Department of Environmental Sciences, Venice (Italy); Krueger, K. [Leibniz-Institute of Marine Sciences, IFM-GEOMAR, Kiel (Germany)

    2012-07-15

    Decadal and bi-decadal climate responses to tropical strong volcanic eruptions (SVEs) are inspected in an ensemble simulation covering the last millennium based on the Max Planck Institute - Earth system model. An unprecedentedly large collection of pre-industrial SVEs (up to 45) producing a peak annual-average top-of-atmosphere radiative perturbation larger than -1.5 Wm{sup -2} is investigated by composite analysis. Post-eruption oceanic and atmospheric anomalies coherently describe a fluctuation in the coupled ocean-atmosphere system with an average length of 20-25 years. The study provides a new physically consistent theoretical framework to interpret decadal Northern Hemisphere (NH) regional winter climates variability during the last millennium. The fluctuation particularly involves interactions between the Atlantic meridional overturning circulation and the North Atlantic gyre circulation closely linked to the state of the winter North Atlantic Oscillation. It is characterized by major distinctive details. Among them, the most prominent are: (a) a strong signal amplification in the Arctic region which allows for a sustained strengthened teleconnection between the North Pacific and the North Atlantic during the first post-eruption decade and which entails important implications from oceanic heat transport and from post-eruption sea ice dynamics, and (b) an anomalous surface winter warming emerging over the Scandinavian/Western Russian region around 10-12 years after a major eruption. The simulated long-term climate response to SVEs depends, to some extent, on background conditions. Consequently, ensemble simulations spanning different phases of background multidecadal and longer climate variability are necessary to constrain the range of possible post-eruption decadal evolution of NH regional winter climates. (orig.)

  2. Piecewise mass flows within a solar prominence observed by the New Vacuum Solar Telescope

    Science.gov (United States)

    Li, Hongbo; Liu, Yu; Tam, Kuan Vai; Zhao, Mingyu; Zhang, Xuefei

    2018-06-01

    The material of solar prominences is often observed in a state of flowing. These mass flows (MF) are important and useful for us to understand the internal structure and dynamics of prominences. In this paper, we present a high resolution Hα observation of MFs within a quiescent solar prominence. From the observation, we find that the plasma primarily has a circular motion and a downward motion separately in the middle section and legs of the prominence, which creates a piecewise mass flow along the observed prominence. Moreover, the observation also shows a clear displacement of MF's velocity peaks in the middle section of the prominence. All of these provide us with a detailed record of MFs within a solar prominence and show a new approach to detecting the physical properties of prominence.

  3. Prominent central spinal canal on MRI - normal variant or pathology

    International Nuclear Information System (INIS)

    Dugal, T.P.; Brazier, D.; Roche, J.

    2002-01-01

    Full text: The sensitivity of MRI can make differentiation of normal from abnormal challenging.The study investigates whether a visible central spinal canal is pathological or a normal variant. We review eight MRI (mostly on a 1.5 Tesla unit) cases where there is a visible central cavity in keeping with a central canal and review the literature. The central canal is a space in the medial part of the grey-matter commissure between the anterior and posterior horns. Histopathological studies show that the canal is present at birth with the majority showing subsequent involution but is uncommonly imaged on MRI. The main differential diagnosis is syringomyelia which usually presents with deficits in pain and sensation corresponding to the appropriate level often with a demonstrable aetiology. Two thirds of our patients were female with an average age of thirty-six years (range 26-45). The patients were largely asymptomatic or their symptoms appeared unrelated to the imaging findings. Three patients had minor previous trauma and two others had non-bacterial meningitis up to twenty years earlier. No patient had known spinal surgery or trauma.The cavity corresponded tomographically to the expected site of the central canal. The canal was in the thoracic location. The canal diameter ranged from one to five millimetres and its length varied from one half a vertebral body height to extending over the entire thoracic region. Its configuration was either filiform or fusiform, with smooth contours. No predisposing features to suggest syringomyelia or other structural abnormalities were noted. Where Gadolinium was given no abnormal enhancement was observed. These cases add to the literature and suggest that these prominent canals are largely asymptomatic and should be viewed as normal variants. Copyright (2002) Blackwell Science Pty Ltd

  4. Topicality and Text Pragmatic Prominence Five Hierarchies Regarding the Topic Suitability of Nominal Constituents

    DEFF Research Database (Denmark)

    Korzen, Iørn

    2015-01-01

    This paper presents and discusses a description of topicality and text pragmatic prominence of nominal discourse referents based on four hierarchies. These hierarchies concern the referent with respect to (a) its identifiability (± identifiable), (b) its referentiality (e.g. deictic, specific...... incorporation of the NP designating the referent, (2) the linguistic material of anaphors linked to the NP, and (3) various phenomena linked to the possible clefting of the NP. The paper also demonstrates that the proposed model and taxonomy is very well suited as tertium comparationis in a cross......-linguistic approach, not least in typological comparisons between for instance Romance and Germanic languages. The correlations described are viewed cross-linguistically with evidence from Italian, Danish, and English....

  5. The 1793 Eruption of San Martin Volcano (Los Tuxtlas, Veracruz, Mexico)

    Science.gov (United States)

    Espindola, J. M.; Zamora-Camacho, A.; Godinez, M. L.; Rodriguez-Elizarraras, S.

    2007-12-01

    San Martin Tuxtla Volcano is located in the State of Veracruz, Eastern Mexico (18.572N, 95.169W, 1650 masl). Its last eruption, which occurred 1793, was described by D. Jose Moziño, a naturalist sent by the Viceroy-of the then New Spain-to report on the eruption. The activity lasted for several months with distinct events of explosive character, which produced thick ash fall deposits in its vicinity. The explosions were heard, among other places, in the coasts of Tampico some 500km NW from the volcano. The ash fall reached distances up to 200 Km from the crater and covered an area of about 112,000 Km2. Following the description of Moziño and the results of field studies we make a reconstruction of the eruption. We identified the air fall deposit from this eruption and present an isopach map. We present radiocarbon ages of the paleosoils under the ash bed as an indirect evidence of its age. This data together with present day wind velocities, and a diffusion-advection model of the dispersion of ashes allow to estimate in at least 10km the altitude reached by some of the eruptive plumes. An estimation of the minimum volume of ash erupted, based on the reconstructed isopachs, is of about 1.3 x 108 m3. Microphotographs of the ashes suggest that the activity was of phreatomagmatic and strombolian nature. Finally, we address some aspects of the volcanic risk in the area derived from our study.

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

    Science.gov (United States)

    Tupper, A. C.; Jansons, E.

    2014-12-01

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

  7. Linking the Lusi mud eruption dynamics with regional and global seismic activity: a statistical analysis.

    Science.gov (United States)

    Collignon, Marine; Hammer, Øyvind; Fallahi, Mohammad J.; Lupi, Matteo; Schmid, Daniel W.; Alwi, Husein; Hadi, Soffian; Mazzini, Adriano

    2017-04-01

    The 29th May 2006, gas water and mud breccia started to erupt at several localities along the Watukosek fault system in the Sidoarjo Regency in East Java Indonesia. The most prominent eruption site, named Lusi, is still active and the emitted material now covers a surface of nearly 7 km2, resulting in the displacement of 60.000 people (up to date). Due to its social and economic impacts, as well as its spectacular dimensions, the Lusi eruption still attracts the attention of international media and scientists. In the framework of the Lusi Lab project (ERC grant n° 308126), many efforts were made to develop a quasi-constant monitoring of the site and the regional areas. Several studies attempted to predict the flow rate evolution or ground deformation, resulting in either overestimating or underestimating the longevity of the eruption. Models have failed because Lusi is not a mud volcano but a sedimentary hosted hydrothermal system that became apparent after the M6.3 Yogyakarta earthquake. Another reason is because such models usually assume that the flow will decrease pacing the overpressure reduction during the deflation of the chamber. These models typically consider a closed system with a unique chamber that is not being recharged. Overall the flow rate has decreased over the past ten years, although it has been largely fluctuating with monthly periods of higher mud breccia discharge. Monitoring of the eruption has revealed that numerous anomalous events are temporally linked to punctual events such as earthquakes or volcanic eruptions. Nevertheless, the quantification of these events has never been investigated in details. In this study, we present a compilation of anomalous events observed at the Lusi site during the last 10 years. Using Monte Carlo simulations, we then statistically compare the displacement, recorded at different seismic stations around Lusi, with the regional and global earthquakes catalogue to test the probability that an earthquake

  8. Evolving Coronal Holes and Interplanetary Erupting Stream ...

    Indian Academy of Sciences (India)

    prominences, have a significantly higher rate of occurrence in the vicinity of coronal .... coronal holes due to the birth of new holes or the growth of existing holes. .... Statistics of newly formed coronal hole areas (NFOCHA) associated with ...

  9. Opal-A in glassy pumice, acid alteration, and the 1817 phreatomagmatic eruption at Kawah Ijen (Java), Indonesia

    Science.gov (United States)

    Lowenstern, Jacob B.; van Hinsberg, Vincent; Berlo, Kim; Liesegang, Moritz; Iacovino, Kayla D.; Bindeman, Ilya N.; Wright, Heather M.

    2018-01-01

    At Kawah Ijen (Indonesia), vigorous SO2 and HCl degassing sustains a hyperacid lake (pH ~0) and intensely alters the subsurface, producing widespread residual silica and advanced argillic alteration products. In 1817, a VEI 2 phreatomagmatic eruption evacuated the lake, depositing a widespread layer of muddy ash fall, and sending lahars down river drainages. We discovered multiple types of opaline silica in juvenile low-silica dacite pumice and in particles within co-erupted laharic sediments. Most spectacular are opal-replaced phenocrysts of plagioclase and pyroxene adjacent to pristine matrix glass and melt inclusions. Opal-bearing pumice has been found at numerous sites, including where post-eruption infiltration of acid water is unlikely. Through detailed analyses of an initial sampling of 1817 eruption products, we find evidence for multiple origins of opaline materials in pumice and laharic sediments. Evidently, magma encountered acid-altered materials in the subsurface and triggered phreatomagmatic eruptions. Syn-eruptive incorporation of opal-alunite clasts, layered opal, and fragment-filled vesicles of opal and glass, all suggest magma-rock interactions in concert with vesiculation, followed by cooling within minutes. Our experiments at magmatic temperature confirm that the opaline materials would show noticeable degradation in time periods longer than a few tens of minutes. Some glassy laharic sedimentary grains are more andesitic than the main pumice type and may represent older volcanic materials that were altered beneath the lake bottom and were forcefully ejected during the 1817 eruption. A post-eruptive origin remains likely for most of the opal-replaced phenocrysts in pumice. Experiments at 25°C and 100°C reveal that when fresh pumice is bathed in Kawah Ijen hyperacid fluid for 6 weeks, plagioclase is replaced without altering either matrix glass or melt inclusions. Moreover, lack of evidence for high-temperature annealing of the opal suggests

  10. Opal-A in Glassy Pumice, Acid Alteration, and the 1817 Phreatomagmatic Eruption at Kawah Ijen (Java), Indonesia

    Science.gov (United States)

    Lowenstern, Jacob B.; van Hinsberg, Vincent; Berlo, Kim; Liesegang, Moritz; Iacovino, Kayla; Bindeman, Ilya N.; Wright, Heather M.

    2018-02-01

    At Kawah Ijen (Indonesia), vigorous SO2 and HCl degassing sustains a hyperacid lake (pH 0) and intensely alters the subsurface, producing widespread residual silica and advanced argillic alteration products. In 1817, a VEI 2 phreatomagmatic eruption evacuated the lake, depositing a widespread layer of muddy ash fall, and sending lahars down river drainages. We discovered multiple types of opaline silica in juvenile low-silica dacite pumice and in particles within co-erupted laharic sediments. Most spectacular are opal-replaced phenocrysts of plagioclase and pyroxene adjacent to pristine matrix glass and melt inclusions. Opal-bearing pumice has been found at numerous sites, including where post-eruption infiltration of acid water is unlikely. Through detailed analyses of an initial sampling of 1817 eruption products, we find evidence for multiple origins of opaline materials in pumice and laharic sediments. Evidently, magma encountered acid-altered materials in the subsurface and triggered phreatomagmatic eruptions. Syn-eruptive incorporation of opal-alunite clasts, layered opal, and fragment-filled vesicles of opal and glass, all suggest magma-rock interactions in concert with vesiculation, followed by cooling within minutes. Our experiments at magmatic temperature confirm that the opaline materials would show noticeable degradation in time periods longer than a few tens of minutes. Some glassy laharic sedimentary grains are more andesitic than the main pumice type and may represent older volcanic materials that were altered beneath the lake bottom and were forcefully ejected during the 1817 eruption. A post-eruptive origin remains likely for most of the opal-replaced phenocrysts in pumice. Experiments at 25°C and 100°C reveal that when fresh pumice is bathed in Kawah Ijen hyperacid fluid for six weeks, plagioclase is replaced without altering either matrix glass or melt inclusions. Moreover, lack of evidence for high-temperature annealing of the opal suggests

  11. Atmospheric processes affecting the separation of volcanic ash and SO2 in volcanic eruptions: inferences from the May 2011 Grímsvötn eruption

    Directory of Open Access Journals (Sweden)

    F. Prata

    2017-09-01

    Full Text Available The separation of volcanic ash and sulfur dioxide (SO2 gas is sometimes observed during volcanic eruptions. The exact conditions under which separation occurs are not fully understood but the phenomenon is of importance because of the effects volcanic emissions have on aviation, on the environment, and on the earth's radiation balance. The eruption of Grímsvötn, a subglacial volcano under the Vatnajökull glacier in Iceland during 21–28 May 2011 produced one of the most spectacular examples of ash and SO2 separation, which led to errors in the forecasting of ash in the atmosphere over northern Europe. Satellite data from several sources coupled with meteorological wind data and photographic evidence suggest that the eruption column was unable to sustain itself, resulting in a large deposition of ash, which left a low-level ash-rich atmospheric plume moving southwards and then eastwards towards the southern Scandinavian coast and a high-level predominantly SO2 plume travelling northwards and then spreading eastwards and westwards. Here we provide observational and modelling perspectives on the separation of ash and SO2 and present quantitative estimates of the masses of ash and SO2 that erupted, the directions of transport, and the likely impacts. We hypothesise that a partial column collapse or sloughing fed with ash from pyroclastic density currents (PDCs occurred during the early stage of the eruption, leading to an ash-laden gravity intrusion that was swept southwards, separated from the main column. Our model suggests that water-mediated aggregation caused enhanced ash removal because of the plentiful supply of source water from melted glacial ice and from entrained atmospheric water. The analysis also suggests that ash and SO2 should be treated with separate source terms, leading to improvements in forecasting the movement of both types of emissions.

  12. Atmospheric processes affecting the separation of volcanic ash and SO2 in volcanic eruptions: inferences from the May 2011 Grímsvötn eruption

    Science.gov (United States)

    Prata, Fred; Woodhouse, Mark; Huppert, Herbert E.; Prata, Andrew; Thordarson, Thor; Carn, Simon

    2017-09-01

    The separation of volcanic ash and sulfur dioxide (SO2) gas is sometimes observed during volcanic eruptions. The exact conditions under which separation occurs are not fully understood but the phenomenon is of importance because of the effects volcanic emissions have on aviation, on the environment, and on the earth's radiation balance. The eruption of Grímsvötn, a subglacial volcano under the Vatnajökull glacier in Iceland during 21-28 May 2011 produced one of the most spectacular examples of ash and SO2 separation, which led to errors in the forecasting of ash in the atmosphere over northern Europe. Satellite data from several sources coupled with meteorological wind data and photographic evidence suggest that the eruption column was unable to sustain itself, resulting in a large deposition of ash, which left a low-level ash-rich atmospheric plume moving southwards and then eastwards towards the southern Scandinavian coast and a high-level predominantly SO2 plume travelling northwards and then spreading eastwards and westwards. Here we provide observational and modelling perspectives on the separation of ash and SO2 and present quantitative estimates of the masses of ash and SO2 that erupted, the directions of transport, and the likely impacts. We hypothesise that a partial column collapse or sloughing fed with ash from pyroclastic density currents (PDCs) occurred during the early stage of the eruption, leading to an ash-laden gravity intrusion that was swept southwards, separated from the main column. Our model suggests that water-mediated aggregation caused enhanced ash removal because of the plentiful supply of source water from melted glacial ice and from entrained atmospheric water. The analysis also suggests that ash and SO2 should be treated with separate source terms, leading to improvements in forecasting the movement of both types of emissions.

  13. The 1902-3 eruptions of the Soufrière, St Vincent: Impacts, relief and response

    Science.gov (United States)

    Pyle, David M.; Barclay, Jenni; Armijos, Maria Teresa

    2018-05-01

    Retrospective analysis of the contemporary colonial and scientific records of a major explosive eruption of the Soufrière of St Vincent from 1902 to 1903 reveals how this significant and prolonged event presented challenges to the authorities charged with managing the crisis and its aftermath. In a small-island setting vulnerable to multiple hazards, the spatial footprint of the volcanic hazard and the nature and intensity of the hazard effects were rather different to those of other recurrent hazards such as hurricanes. The eruption affected the same parts of the island that had been impacted by prior explosive eruptions in 1718 and 1812, and hurricanes in 1831 and 1898, with consequences that disproportionately affected those working in and around the large sugar estates. The official response to the eruption, both in terms of short-term relief and remediation, was significantly accelerated by the existence of mature plans for land-reform following the collapse of the sugar market, and ongoing plans for rebuilding in the aftermath of the destructive hurricane of 1898. The picture that this analysis helps to illuminate provides insights both into the nature of the particular eruptive episode, and the human and social response to that episode. This not only informs discussion and planning for future explosive eruptions on St Vincent, but provides important empirical evidence for building effective responses in similar multihazard contexts.

  14. Magma viscosity estimation based on analysis of erupted products. Potential assessment for large-scale pyroclastic eruptions

    International Nuclear Information System (INIS)

    Takeuchi, Shingo

    2010-01-01

    After the formulation of guidelines for volcanic hazards in site evaluation for nuclear installations (e.g. JEAG4625-2009), it is required to establish appropriate methods to assess potential of large-scale pyroclastic eruptions at long-dormant volcanoes, which is one of the most hazardous volcanic phenomena on the safety of the installations. In considering the volcanic dormancy, magma eruptability is an important concept. The magma eruptability is dominantly controlled by magma viscosity, which can be estimated from petrological analysis of erupted materials. Therefore, viscosity estimation of magmas erupted in past eruptions should provide important information to assess future activities at hazardous volcanoes. In order to show the importance of magma viscosity in the concept of magma eruptability, this report overviews dike propagation processes from a magma chamber and nature of magma viscosity. Magma viscosity at pre-eruptive conditions of magma chambers were compiled based on previous petrological studies on past eruptions in Japan. There are only 16 examples of eruptions at 9 volcanoes satisfying data requirement for magma viscosity estimation. Estimated magma viscosities range from 10 2 to 10 7 Pa·s for basaltic to rhyolitic magmas. Most of examples fall below dike propagation limit of magma viscosity (ca. 10 6 Pa·s) estimated based on a dike propagation model. Highly viscous magmas (ca. 10 7 Pa·s) than the dike propagation limit are considered to lose eruptability which is the ability to form dikes and initiate eruptions. However, in some cases, small precursory eruptions of less viscous magmas commonly occurred just before climactic eruptions of the highly viscous magmas, suggesting that the precursory dike propagation by the less viscous magmas induced the following eruptions of highly viscous magmas (ca. 10 7 Pa·s). (author)

  15. Global time-size distribution of volcanic eruptions on Earth.

    Science.gov (United States)

    Papale, Paolo

    2018-05-01

    Volcanic eruptions differ enormously in their size and impacts, ranging from quiet lava flow effusions along the volcano flanks to colossal events with the potential to affect our entire civilization. Knowledge of the time and size distribution of volcanic eruptions is of obvious relevance for understanding the dynamics and behavior of the Earth system, as well as for defining global volcanic risk. From the analysis of recent global databases of volcanic eruptions extending back to more than 2 million years, I show here that the return times of eruptions with similar magnitude follow an exponential distribution. The associated relative frequency of eruptions with different magnitude displays a power law, scale-invariant distribution over at least six orders of magnitude. These results suggest that similar mechanisms subtend to explosive eruptions from small to colossal, raising concerns on the theoretical possibility to predict the magnitude and impact of impending volcanic eruptions.

  16. Morphology and Dynamics of Solar Prominences from 3D MHD Simulations

    Science.gov (United States)

    Terradas, J.; Soler, R.; Luna, M.; Oliver, R.; Ballester, J. L.

    2015-01-01

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  17. MORPHOLOGY AND DYNAMICS OF SOLAR PROMINENCES FROM 3D MHD SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Terradas, J.; Soler, R.; Oliver, R.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Luna, M., E-mail: jaume.terradas@uib.es [Instituto de Astrofísica de Canarias, E-38200 La Laguna, Tenerife (Spain)

    2015-01-20

    In this paper we present a numerical study of the time evolution of solar prominences embedded in sheared magnetic arcades. The prominence is represented by a density enhancement in a background-stratified atmosphere and is connected to the photosphere through the magnetic field. By solving the ideal magnetohydrodynamic equations in three dimensions, we study the dynamics for a range of parameters representative of real prominences. Depending on the parameters considered, we find prominences that are suspended above the photosphere, i.e., detached prominences, but also configurations resembling curtain or hedgerow prominences whose material continuously connects to the photosphere. The plasma-β is an important parameter that determines the shape of the structure. In many cases magnetic Rayleigh-Taylor instabilities and oscillatory phenomena develop. Fingers and plumes are generated, affecting the whole prominence body and producing vertical structures in an essentially horizontal magnetic field. However, magnetic shear is able to reduce or even to suppress this instability.

  18. Contrasting styles of deep-marine pyroclastic eruptions revealed from Axial Seamount push core records

    Science.gov (United States)

    Portner, Ryan A.; Clague, David A.; Helo, Christoph; Dreyer, Brian M.; Paduan, Jennifer B.

    2015-08-01

    bioturbation or other interbedded lithofacies, and presence of normal grading suggests prolonged eruption activity and deposition via turbidity flows or suspension fallout. The proximity of ancient hydrothermal muddy tuff lithofacies and active hydrothermal vents to caldera walls suggest that phreatomagmatic activity was linked to shallow circulation of fluids along caldera ring-faults rooted to underlying magma conduits and shallow reservoirs. This study provides evidence for two distinctly different pyroclastic eruption styles and provides a framework to further develop existing models of deep-sea explosive volcanism.

  19. An Erupted Dilated Odontoma: A Rare Presentation

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2016-01-01

    Full Text Available A dilated odontoma is an extremely rare developmental anomaly represented as a dilatation of the crown and root as a consequence of a deep, enamel-lined invagination and is considered a severe variant of dens invaginatus. An oval shape of the tooth lacking morphological characteristics of a crown or root implies that the invagination happened in the initial stages of morphodifferentiation. Spontaneous eruption of an odontoma is a rare occurrence and the occurrence of a dilated odontoma in a supernumerary tooth is even rarer with only a few case reports documented in the English literature. We present an extremely rare case of erupted dilated odontoma occurring in the supernumerary tooth in anterior maxillary region in an 18-year-old male, which, to the best of our knowledge, is the first ever case reported in English literature.

  20. Fine particles in the Soufriere eruption plume

    Science.gov (United States)

    Woods, D. C.; Chuan, R. L.

    1982-01-01

    The size distributions of fine particles measured at tropospheric altitudes in the periphery of the eruption plume formed during the April 17, 1979 eruption of Soufriere Volcano and in the low-level effluents on May 15, 1979 were found to be bimodal, having peak concentrations at geometric mean diameters of 1.1 and 0.23 micrometers. Scanning electron microscopy and energy-dispersive X-ray analysis of the samples revealed an abundance of aluminum and silicon and traces of sodium, magnesium, chlorine, potassium, calcium, and iron in the large-particle mode. The submicrometer-sized particles were covered with liquid containing sulfur, assumed to be in the form of liquid sulfuric acid.

  1. When does eruption run-up begin? Multidisciplinary insight from the 1999 eruption of Shishaldin volcano

    Science.gov (United States)

    Rasmussen, Daniel J.; Plank, Terry A.; Roman, Diana C.; Power, John A.; Bodnar, Robert J.; Hauri, Erik H.

    2018-03-01

    During the run-up to eruption, volcanoes often show geophysically detectable signs of unrest. However, there are long-standing challenges in interpreting the signals and evaluating the likelihood of eruption, especially during the early stages of volcanic unrest. Considerable insight can be gained from combined geochemical and geophysical studies. Here we take such an approach to better understand the beginning of eruption run-up, viewed through the lens of the 1999 sub-Plinian basaltic eruption of Shishaldin volcano, Alaska. The eruption is of interest due to its lack of observed deformation and its apparent long run-up time (9 months), following a deep long-period earthquake swarm. We evaluate the nature and timing of recharge by examining the composition of 138 olivine macrocrysts and 53 olivine-hosted melt inclusions and through shear-wave splitting analysis of regional earthquakes. Magma mixing is recorded in three crystal populations: a dominant population of evolved olivines (Fo60-69) that are mostly reversely zoned, an intermediate population (Fo69-76) with mixed zonation, and a small population of normally zoned more primitive olivines (Fo76-80). Mixing-to-eruption timescales are obtained through modeling of Fe-Mg interdiffusion in 78 olivines. The large number of resultant timescales provides a thorough record of mixing, demonstrating at least three mixing events: a minor event ∼11 months prior to eruption, overlapping within uncertainty with the onset of deep long-period seismicity; a major event ∼50 days before eruption, coincident with a large (M5.2) shallow earthquake; and a final event about a week prior to eruption. Shear-wave splitting analysis shows a change in the orientation of the local stress field about a month after the deep long-period swarm and around the time of the M5.2 event. Earthquake depths and vapor saturation pressures of Raman-reconstructed melt inclusions indicate that the recharge magma originated from depths of at least 20

  2. Terbinafine induced pityriasis rosea-like eruption.

    Science.gov (United States)

    George, Anisha; Bhatia, Anuradha; Kanish, Bimal; Williams, Abhilasha

    2015-01-01

    Terbinafine is an allylamine antifungal agent which is widely used for the treatment of fungal infections. Cutaneous side effects have been reported in 2% of the patients on terbinafine therapy with many morphological patterns. We report a case of terbinafine induced pityriasis rosea, a very rare side effect of terbinafine. This report emphasizes the importance of counseling the patient to report immediately in the event of a cutaneous eruption.

  3. Terbinafine induced pityriasis rosea-like eruption

    OpenAIRE

    Anisha George; Anuradha Bhatia; Bimal Kanish; Abhilasha Williams

    2015-01-01

    Terbinafine is an allylamine antifungal agent which is widely used for the treatment of fungal infections. Cutaneous side effects have been reported in 2% of the patients on terbinafine therapy with many morphological patterns. We report a case of terbinafine induced pityriasis rosea, a very rare side effect of terbinafine. This report emphasizes the importance of counseling the patient to report immediately in the event of a cutaneous eruption.

  4. Interceptive management of eruption disturbances: case report.

    Science.gov (United States)

    Cozza, Paola; Marino, Alessandra; Lagana, Giuseppina

    2004-01-01

    The aim of the present report is to describe a case of a patient with eruption disturbances of an ankylosed lower primary second molar, delayed development of a maxillary permanent canine associated with an odontoma and a class III dental malocclusion. In such a case the objectives of treatment are: to prevent impaction of the lower second premolar and tipping of the lower first molar; to establish correct anterior overbite and overjet and to control the development of the permanent upper canine.

  5. Cellular and molecular basis of tooth eruption

    Science.gov (United States)

    Wise, GE

    2009-01-01

    Objectives Tooth eruption requires the presence of a dental follicle (DF), alveolar bone resorption for an eruption pathway, and alveolar bone formation at the base of the bony crypt. The objectives of our investigations have been to determine how the DF regulates both the osteoclastogenesis and osteogenesis needed for eruption. Material & Methods Multiple experimental methods have been employed. Results The DF regulates osteoclastogenesis and osteogenesis by regulating the expression of critical genes in both a chronological and spatial fashion. In the rat 1st mandibular molar there is a major burst of osteoclastogenesis at day 3 postnatally and a minor burst at day 10. At day 3, the DF maximally expresses colony-stimulating factor-1 (CSF-1) to down-regulate the expression of osteoprotegerin such that osteoclastogenesis can occur. At day 10, the minor burst of osteoclastogenesis is promoted by upregulation of VEGF and RANKL in the DF. Spatially, the bone resorption is in the coronal portion of the bony crypt and genes such as RANKL are expressed more in the coronal region of the DF than in its basal one-half. For osteogenesis, bone formation begins at day 3 at the base of the bony crypt and maximal growth is at days 9–14. Osteo-inductive genes such as BMP-2 appear to promote this and are expressed more in the basal half of the DF than in the coronal. Conclusion The osteoclastogenesis and osteogenesis needed for eruption are regulated by differential gene expression in the DF both chronologically and spatially. PMID:19419449

  6. Effect of early childhood malnutrition on tooth eruption in Haitian adolescents.

    Science.gov (United States)

    Psoter, W; Gebrian, B; Prophete, S; Reid, B; Katz, R

    2008-04-01

    The objective of this retrospective cohort study was to determine the effects of early childhood protein-energy malnutrition (EC-PEM) and current nutritional status as defined by anthropomorphic measures on the exfoliation and eruption patterns of teeth among adolescents. Oral clinical examinations were conducted in 2005 using World Health Organization (WHO) diagnostic criteria on 498 11- to 13-year-old Haitians for whom early childhood malnutrition data were available. Anthropomorphic records (weight-for-age) from the Haitian Health Foundation computerized database on children from birth through 5-years old were utilized. Current heights and weights were ascertained. Both sets of data were converted to z-scores based on the National Center for Health Statistics (NCHS) referent database. Based upon these z-scores, EC-PEM and current malnutrition categories were developed for this study. The analyses separately regressed the number of primary and permanent teeth on age, gender, EC-PEM status and current nutritional status. Both a delayed exfoliation of primary teeth and a delayed eruption of permanent teeth were associated with EC-PEM and current stunting in adolescence. The observed associations were either direct and statistically significant or indirectly demonstrated by presenting evidence of confounding. The overall interpretation of the models is that malnutrition beginning in the earliest years and extending throughout childhood influences the exfoliation and eruption of teeth. These findings present evidence of an association between tooth exfoliation/eruption patterns and both EC-PEM and nutritional insufficiency (stunting) throughout childhood. This observed delay in the exfoliation of the primary dentition and in the eruption of the permanent dentition has practical significance in interpreting age-specific dental caries data from populations with different malnutrition experiences.

  7. A cascade of magmatic events during the assembly and eruption of a super-sized magma body

    Science.gov (United States)

    Allan, Aidan. S. R.; Barker, Simon J.; Millet, Marc-Alban; Morgan, Daniel J.; Rooyakkers, Shane M.; Schipper, C. Ian; Wilson, Colin J. N.

    2017-07-01

    magmas with the mush and melt-dominant body. However, the mafic magmas do not appear to have triggered the eruption or controlled magmatic temperatures in the erupted rhyolite. Integration of textural and compositional data from all available crystal types, across all dominant and subordinate magmatic components, allow the history of the Oruanui magma body to be reconstructed over a wide range of temporal scales using multiple techniques. This history spans the tens of millennia required to grow the parental magma system (U-Th disequilibrium dating in zircon), through the centuries and decades required to assemble the eruptible magma body (textural and diffusion modelling in orthopyroxene), to the months, days, hours and minutes over which individual phases of the eruption occurred, identified through field observations tied to diffusion modelling in magnetite, olivine, quartz and feldspar. Tectonic processes, rather than any inherent characteristics of the magmatic system, were a principal factor acting to drive the rapid accumulation of magma and control its release episodically during the eruption. This work highlights the richness of information that can be gained by integrating multiple lines of petrologic evidence into a holistic timeline of field-verifiable processes.

  8. Eruption products of the 1883 eruption of Krakatau and their final settlement

    Directory of Open Access Journals (Sweden)

    Izumi Yokoyama

    2015-06-01

    Full Text Available Firstly the volume of pyroclastic ejecta during the 1883 eruption of Krakatau is re-examined. To revise the volume of flow deposits, the author basically follows Verbeek’s observation while to estimate the fall deposits, as the last resort, the author assumes that volume ratios fall / flow are common to similar caldera eruptions, and the ratios determined by the caldera- forming eruptions of Novarupta and Pinatubo are applied to the Krakatau eruption. Verbeek’s estimation of the total volume of ejecta, 12 km3 is revised to 19 km3. This is significantly different from the volume of disrupted volcano edifice, 8 km3. Such a result does not support the predecessors’ hypothesis that calderas are formed by collapses of volcano edifices into magma reservoirs in replacement of the total ejecta. Through the discussion on the volume estimation of volcanic ejecta on and around Krakatau, the author recognizes that such estimation should be originally very difficult to attain enough accuracy. Much importance of “caldera deposits” to post-eruption settlements of the ejecta is emphasized. In relation to caldera formation, mechanical stability of a cavity in the crust is discussed. Lastly, upon the basis of subsurface structure, especially caldera deposits, a structural image of Krakatau caldera is presented.

  9. Characterize Eruptive Processes at Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    D. Krier

    2004-01-01

    The purpose of this scientific analysis report, ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', is to present information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a repository at Yucca Mountain. This scientific analysis report provides information to four other reports: ''Number of Waste Packages Hit by Igneous Intrusion'', (BSC 2004 [DIRS 170001]); ''Atmospheric Dispersal and Deposition of Tephra from Potential Volcanic Eruption at Yucca Mountain, Nevada'' (BSC 2004 [DIRS 170026]); ''Dike/Drift Interactions'' (BSC 2004 [DIRS 170028]); ''Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV'' (BSC 2004 [DIRS 170027], Section 6.5). This report is organized into seven major sections. This section addresses the purpose of this document. Section 2 addresses quality assurance, Section 3 the use of software, Section 4 identifies the requirements that constrain this work, and Section 5 lists assumptions and their rationale. Section 6 presents the details of the scientific analysis and Section 7 summarizes the conclusions reached

  10. Drug eruptions from phenylbutazone in Jamu.

    Science.gov (United States)

    Giam, Y C; Tham, S N; Tan, T; Lim, A

    1986-01-01

    Drug eruptions from indeginous medicine is often difficult to diagnosis and confirm. It is known that a number of these now supplied by bomohs and Chinese sinsehs contain known drugs and are dispensed as tablets and capsules. We report 3 cases of adverse drug eruption to "Jamu", a Malay herb. A particular brand, "Jamu Indonesia, Toko Air Pancur", from Johor Bahru, Malaysia, is especially recommended for "sakit pinggang" or backache. The cases occurred between January and February 1985, and all had taken brown kidney shaped tablets. The adverse reactions were moderately severe. Two had erythroderma with hepatitis, and one, Steven Johnson Syndrome. Analysis of this jamu for analgesics led to the discovery of adulteration with phenylbutazone and diazepam. Records from local cases from 1974-1984 showed that 8 other patients, all Chinese had adverse cutaneous eruptions from phenylbutazone, oxybutazone and propyphenazone. The skin manifestations were erythroderma (2 cases), vasculitis (2 cases) and toxic epidermal necrolysis (4 cases). Those with toxic epidermal necrolysis had 100% mortality.

  11. Characterize Eruptive Processes at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    D. Krier

    2004-10-04

    The purpose of this scientific analysis report, ''Characterize Eruptive Processes at Yucca Mountain, Nevada'', is to present information about natural volcanic systems and the parameters that can be used to model their behavior. This information is used to develop parameter-value distributions appropriate for analysis of the consequences of volcanic eruptions through a repository at Yucca Mountain. This scientific analysis report provides information to four other reports: ''Number of Waste Packages Hit by Igneous Intrusion'', (BSC 2004 [DIRS 170001]); ''Atmospheric Dispersal and Deposition of Tephra from Potential Volcanic Eruption at Yucca Mountain, Nevada'' (BSC 2004 [DIRS 170026]); ''Dike/Drift Interactions'' (BSC 2004 [DIRS 170028]); ''Development of Earthquake Ground Motion Input for Preclosure Seismic Design and Postclosure Performance Assessment of a Geologic Repository at Yucca Mountain, NV'' (BSC 2004 [DIRS 170027], Section 6.5). This report is organized into seven major sections. This section addresses the purpose of this document. Section 2 addresses quality assurance, Section 3 the use of software, Section 4 identifies the requirements that constrain this work, and Section 5 lists assumptions and their rationale. Section 6 presents the details of the scientific analysis and Section 7 summarizes the conclusions reached.

  12. SOLAR MULTIPLE ERUPTIONS FROM A CONFINED MAGNETIC STRUCTURE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeongwoo; Chae, Jongchul [Department of Physics and Astronomy, Seoul National University, Seoul 08826 (Korea, Republic of); Liu, Chang; Jing, Ju [Space Weather Research Laboratory, New Jersey Institute of Technology, Newark, NJ 07102 (United States)

    2016-09-20

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encircling the AR was present before the eruptions; (ii) expansion of the open–closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  13. SOLAR MULTIPLE ERUPTIONS FROM A CONFINED MAGNETIC STRUCTURE

    International Nuclear Information System (INIS)

    Lee, Jeongwoo; Chae, Jongchul; Liu, Chang; Jing, Ju

    2016-01-01

    How eruption can recur from a confined magnetic structure is discussed based on the Solar Dynamics Observatory observations of the NOAA active region 11444, which produced three eruptions within 1.5 hr on 2012 March 27. The active region (AR) had the positive-polarity magnetic fields in the center surrounded by the negative-polarity fields around. Since such a distribution of magnetic polarity tends to form a dome-like magnetic fan structure confined over the AR, the multiple eruptions were puzzling. Our investigation reveals that this event exhibits several properties distinct from other eruptions associated with magnetic fan structures: (i) a long filament encircling the AR was present before the eruptions; (ii) expansion of the open–closed boundary (OCB) of the field lines after each eruption was suggestive of the growing fan-dome structure, and (iii) the ribbons inside the closed magnetic polarity inversion line evolved in response to the expanding OCB. It thus appears that in spite of multiple eruptions the fan-dome structure remained undamaged, and the closing back field lines after each eruption rather reinforced the fan-dome structure. We argue that the multiple eruptions could occur in this AR in spite of its confined magnetic structure because the filament encircling the AR was adequate for slipping through the magnetic separatrix to minimize the damage to its overlying fan-dome structure. The result of this study provides a new insight into the productivity of eruptions from a confined magnetic structure.

  14. Reconstruction of the dynamics of the 1800-1801 Hualalai eruption: Implications for planetary lava flows

    Science.gov (United States)

    Baloga, Stephen; Spudis, Paul

    1993-01-01

    The 1800-1801 eruption of alkalic basalt from the Hualalai volcano, Hawaii provides a unique opportunity for investigating the dynamics of lava flow emplacement with eruption rates and compositions comparable to those that have been suggested for planetary eruptions. Field observations suggest new considerations must be used to reconstruct the emplacement of these lava flows. These observations are: (1) the flow traversed the 15 km from the vent to the sea so rapidly that no significant crust formed and an observation of the eruption reported that the flow reach the sea from the vent in approximately 1 hour; (2) the drainage of beds of xenolith nodules indicates a highly fluid, low viscosity lava; (3) overspills and other morphologic evidence for a very low viscosity host fluid; (4) no significant longitudinal increase in flow thickness that might be associated with an increase in the rheological properties of the lava; and (5) the relatively large size of channels associated with the flow, up to 80 meters across and several km long. Models for many geologic mass movements and fast moving fluids with various loadings and suspensions are discussed.

  15. Classification of mini-dimmings associated with extreme ultraviolet eruptions by using graph theory

    Directory of Open Access Journals (Sweden)

    S Bazargan

    2016-09-01

    Full Text Available Coronal dimmings in both micro and macro scales, can be observed by extreme ultraviolet images, recorded from Solar Dynamics Observatory or Atmospheric Imaging Assembly (SDO/AIA. Mini-dimmings are sometimes associated with wave-like brightening, called coronal mass ejections. Here, the sun full disk images with 171 Å wavelenght, cadence of 2.5, and  0.6 arcsec cell size, were taken on 3 March 2012, then the obtained data were analyzed. Using Zernike Moment and Support Vector Machine (SVM, mini dimmings are detected. 538 active region events, 680 coronal hole events and 723 quiet sun events have been recognized using algorithm. The position, time duration and spatial expansion of these events were computed .The eruptive dimmings have a more spatial development than thermal dimmings after eruptions. This is evident in their graph characteristics length. Then, using graph theory, eruptive and thermal mini-dimmings were classified, with 13% error, for 200 dimmings. 68 dimmings were classified as thermal, and 132 as eruptive. To do this, evolution of graph characteristic length were used.

  16. Enhanced ice sheet melting driven by volcanic eruptions during the last deglaciation.

    Science.gov (United States)

    Muschitiello, Francesco; Pausata, Francesco S R; Lea, James M; Mair, Douglas W F; Wohlfarth, Barbara

    2017-10-24

    Volcanic eruptions can impact the mass balance of ice sheets through changes in climate and the radiative properties of the ice. Yet, empirical evidence highlighting the sensitivity of ancient ice sheets to volcanism is scarce. Here we present an exceptionally well-dated annual glacial varve chronology recording the melting history of the Fennoscandian Ice Sheet at the end of the last deglaciation (∼13,200-12,000 years ago). Our data indicate that abrupt ice melting events coincide with volcanogenic aerosol emissions recorded in Greenland ice cores. We suggest that enhanced ice sheet runoff is primarily associated with albedo effects due to deposition of ash sourced from high-latitude volcanic eruptions. Climate and snowpack mass-balance simulations show evidence for enhanced ice sheet runoff under volcanically forced conditions despite atmospheric cooling. The sensitivity of past ice sheets to volcanic ashfall highlights the need for an accurate coupling between atmosphere and ice sheet components in climate models.

  17. Hubble Captures Volcanic Eruption Plume From Io

    Science.gov (United States)

    1997-01-01

    The Hubble Space Telescope has snapped a picture of a 400-km-high (250-mile-high) plume of gas and dust from a volcanic eruption on Io, Jupiter's large innermost moon.Io was passing in front of Jupiter when this image was taken by the Wide Field and Planetary Camera 2 in July 1996. The plume appears as an orange patch just off the edge of Io in the eight o'clock position, against the blue background of Jupiter's clouds. Io's volcanic eruptions blasts material hundreds of kilometers into space in giant plumes of gas and dust. In this image, material must have been blown out of the volcano at more than 2,000 mph to form a plume of this size, which is the largest yet seen on Io.Until now, these plumes have only been seen by spacecraft near Jupiter, and their detection from the Earth-orbiting Hubble Space Telescope opens up new opportunities for long-term studies of these remarkable phenomena.The plume seen here is from Pele, one of Io's most powerful volcanos. Pele's eruptions have been seen before. In March 1979, the Voyager 1 spacecraft recorded a 300-km-high eruption cloud from Pele. But the volcano was inactive when the Voyager 2 spacecraft flew by Jupiter in July 1979. This Hubble observation is the first glimpse of a Pele eruption plume since the Voyager expeditions.Io's volcanic plumes are much taller than those produced by terrestrial volcanos because of a combination of factors. The moon's thin atmosphere offers no resistance to the expanding volcanic gases; its weak gravity (one-sixth that of Earth) allows material to climb higher before falling; and its biggest volcanos are more powerful than most of Earth's volcanos.This image is a contrast-enhanced composite of an ultraviolet image (2600 Angstrom wavelength), shown in blue, and a violet image (4100 Angstrom wavelength), shown in orange. The orange color probably occurs because of the absorption and/or scattering of ultraviolet light in the plume. This light from Jupiter passes through the plume and is

  18. Eruptive history of South Sister, Oregon Cascades

    Science.gov (United States)

    Fierstein, J.; Hildreth, W.; Calvert, A.T.

    2011-01-01

    South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the

  19. Indirect Climatic Effects of Major Volcanic Eruptions

    Science.gov (United States)

    Hofmann, D. J.

    2007-05-01

    The direct effects on climate, related to atmospheric emissions to the atmosphere following major volcanic eruptions, are well-known although the sparseness of such eruptions make detailed study on the range of such variations difficult. In general terms, infrared absorption by volcanic emissions to the stratosphere result in local heating early in the event when gaseous sulfur compounds exist. This early period is followed by gas to particle conversion, on a time scale of 1-2 months, promoting the formation of sulfuric acid-water droplets. Coagulation and droplet growth result in the "volcanic stratospheric aerosol layer" which is related to the predominant direct climatic effect of large eruptions, the cooling of the troposphere by backscattering of solar visible radiation to space with a recovery time scale of 1-2 years. In this paper we will discuss some of the less-known "indirect" effects of the volcanic stratospheric aerosol on climate. We label them indirect as they act on climate through intermediary atmospheric constituents. The intermediaries in the volcanic indirect climatic effect are generally atmospheric greenhouse gases or other atmospheric gases and conditions which affect greenhouse gases. For example, cooling of the troposphere following major eruptions reduces the growth rate of atmospheric carbon dioxide related to respiration by the terrestrial biosphere. In addition, redirection of part of the direct solar beam into diffuse radiation by the volcanic stratospheric aerosol stimulates plant photosynthesis, further reducing the carbon dioxide growth rate. The growth rate of the second-most important atmospheric greenhouse gas, methane, is also affected by volcanic emissions. Volcanic stratospheric aerosol particles provide surface area which catalyzes heterogeneous chemical reactions thus stimulating removal of stratospheric ozone, also a greenhouse gas. Although major droughts usually related to ENSO events have opposite effects on carbon

  20. Active Eruptions in the NE Lau Basin

    Science.gov (United States)

    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 20 yrs the PMEL-Vents and NSF RIDGE programs have sought to observe

  1. Phreatomagmatic eruptive and depositional processes during the 1949 eruption on La Palma (Canary Islands)

    Science.gov (United States)

    White, James D. L.; Schmincke, Hans-Ulrich

    1999-12-01

    In 1949, a 5-week-long magmatic and phreatomagmatic eruption took place along the active volcanic ridge of La Palma (Canary Islands). Two vents, Duraznero and Hoyo Negro, produced significant pyroclastic deposits. The eruption began from Duraznero vent, which produced a series of deposits with an upward decrease in accidental fragments and increase in fluidal ash and spatter, together inferred to indicate decreasing phreatomagmatic interaction. Hoyo Negro erupted over a 2-week period, producing a variety of pyroclastic density currents and ballistic blocks and bombs. Hoyo Negro erupted within and modified an older crater having high walls on the northern to southeastern edges. Southwestern to western margins of the crater lay 50 to 100 m lower. Strongly contrasting deposits in the different sectors (N-SE vs. SW-W) were formed as a result of interaction between topography, weak eruptive columns and stratified pyroclastic density currents. Tephra ring deposits are thicker and coarser-grained than upper rim deposits formed along the higher edges of the crater, and beyond the crater margin, valley-confined deposits are thicker than more thinly bedded mantling deposits on higher topography. These differences indicate that the impact zone for the bulk of the collapsing, tephra-laden column lay within the crater and that the high crater walls inhibited escape of pyroclastic density currents to the north and east. The impact zone lay outside the low SW-W rims, however, thus allowing stratified pyroclastic density currents to move freely away from the crater in those directions, depositing thin sections (<30 cm) of well-bedded ash (mantling deposits) on ridges and thicker sections (1-3 m) of structureless ash beds in valleys and small basins. Such segregation of dense pyroclastic currents from more dilute ones at the crater wall is likely to be common for small eruptions from pre-existing craters and is an important factor to be taken into account in volcanic hazards

  2. Eruptions at Lone Star Geyser, Yellowstone National Park, USA, part 1: energetics and eruption dynamics

    Science.gov (United States)

    Karlstrom, Leif; Hurwitz, Shaul; Sohn, Robert; Vandemeulebrouck, Jean; Murphy, Fred; Rudolph, Maxwell L.; Johnston, Malcolm J.S.; Manga, Michael; McCleskey, R. Blaine

    2013-01-01

    Geysers provide a natural laboratory to study multiphase eruptive processes. We present results from a four–day experiment at Lone Star Geyser in Yellowstone National Park, USA. We simultaneously measured water discharge, acoustic emissions, infraredintensity, and visible and infrared video to quantify the energetics and dynamics of eruptions, occurring approximately every three hours. We define four phases in the eruption cycle: 1) a 28 ± 3 minute phase with liquid and steam fountaining, with maximum jet velocities of 16–28 m s− 1, steam mass fraction of less than ∼ 0.01. Intermittently choked flow and flow oscillations with periods increasing from 20 to 40 s are coincident with a decrease in jet velocity and an increase of steam fraction; 2) a 26 ± 8 minute post–eruption relaxation phase with no discharge from the vent, infrared (IR) and acoustic power oscillations gliding between 30 and 40 s; 3) a 59 ± 13 minute recharge period during which the geyser is quiescent and progressively refills, and 4) a 69 ± 14 minute pre–play period characterized by a series of 5–10 minute–long pulses of steam, small volumes of liquid water discharge and 50–70 s flow oscillations. The erupted waters ascend froma 160 − 170° C reservoir and the volume discharged during the entire eruptive cycle is 20.8 ± 4.1 m3. Assuming isentropic expansion, we calculate a heat output from the geyser of 1.4–1.5 MW, which is < 0.1% of the total heat output from Yellowstone Caldera.

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

    Science.gov (United States)

    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

  4. Serreta 1998-2001 submarine volcanic eruption, offshore Terceira (Azores): Characterization of the vent and inferences about the eruptive dynamics

    Science.gov (United States)

    Casas, David; Pimentel, Adriano; Pacheco, José; Martorelli, Eleonora; Sposato, Andrea; Ercilla, Gemma; Alonso, Belen; Chiocci, Francesco

    2018-05-01

    High-resolution bathymetric data and seafloor sampling were used to characterize the most recent volcanic eruption in the Azores region, the 1998-2001 Serreta submarine eruption. The vent of the eruption is proposed to be an asymmetric topographic high, composed of two coalescing volcanic cones, underlying the location where lava balloons had been observed at the sea surface during the eruption. The volcanic products related to the 1998-2001 eruption are constrained to an area of 0.5 km2 around the proposed vent position. A submarine Strombolian-style eruption producing basaltic lava balloons, ash and coarse scoriaceous materials with limited lateral dispersion led to the buildup of the cones. The 1998-2001 Serreta eruption shares many similarities with other intermediate-depth lava balloon-forming eruptions (e.g., the 1891 eruption offshore Pantelleria and the 2011-2012 eruption south of El Hierro), revealing the particular conditions needed for the production of this unusual and scarcely documented volcanic product.

  5. A comparison study of a solar active-region eruptive filament and a neighboring non-eruptive filament

    Science.gov (United States)

    Jiang, Chao-Wei; Wu, Shi-Tsan; Feng, Xue-Shang; Hu, Qiang

    2016-01-01

    Solar active region (AR) 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE-MHD-NLFFF code reveals that two magnetic flux ropes (MFRs) exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface (BPSS) cospatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament (with a length of about 200 Mm), the eruptive MFR/filament is much smaller (with a length of about 20 Mm), but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption.

  6. A comparison study of a solar active-region eruptive filament and a neighboring non-eruptive filament

    International Nuclear Information System (INIS)

    Jiang, Chao-Wei; Feng, Xue-Shang; Wu, Shi-Tsan; Hu, Qiang

    2016-01-01

    Solar active region (AR) 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using our CESE–MHD–NLFFF code reveals that two magnetic flux ropes (MFRs) exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface (BPSS) cospatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match Hα observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament (with a length of about 200 Mm), the eruptive MFR/filament is much smaller (with a length of about 20 Mm), but it contains most of the magnetic free energy in the extrapolation box and holds a much higher free energy density than the non-eruptive one. Both the MFRs are weakly twisted and cannot trigger kink instability. The AR eruptive MFR is unstable because its axis reaches above a critical height for torus instability, at which the overlying closed arcades can no longer confine the MFR stably. On the contrary, the quiescent MFR is very firmly held by its overlying field, as its axis apex is far below the torus-instability threshold height. Overall, this comparison investigation supports that an MFR can exist prior to eruption and the ideal MHD instability can trigger an MFR eruption. (paper)

  7. Magnetic Field-Vector Measurements in Quiescent Prominences via the Hanle Effect: Analysis of Prominences Observed at Pic-Du-Midi and at Sacramento Peak

    Science.gov (United States)

    Bommier, V.; Leroy, J. L.; Sahal-Brechot, S.

    1985-01-01

    The Hanle effect method for magnetic field vector diagnostics has now provided results on the magnetic field strength and direction in quiescent prominences, from linear polarization measurements in the He I E sub 3 line, performed at the Pic-du-Midi and at Sacramento Peak. However, there is an inescapable ambiguity in the field vector determination: each polarization measurement provides two field vector solutions symmetrical with respect to the line-of-sight. A statistical analysis capable of solving this ambiguity was applied to the large sample of prominences observed at the Pic-du-Midi (Leroy, et al., 1984); the same method of analysis applied to the prominences observed at Sacramento Peak (Athay, et al., 1983) provides results in agreement on the most probable magnetic structure of prominences; these results are detailed. The statistical results were confirmed on favorable individual cases: for 15 prominences observed at Pic-du-Midi, the two-field vectors are pointing on the same side of the prominence, and the alpha angles are large enough with respect to the measurements and interpretation inaccuracies, so that the field polarity is derived without any ambiguity.

  8. Most Powerful Eruption in the Universe Discovered

    Science.gov (United States)

    2005-01-01

    Astronomers have found the most powerful eruption seen in the Universe using NASA's Chandra X-ray Observatory. A supermassive black hole generated this eruption by growing at a remarkable rate. This discovery shows the enormous appetite of large black holes, and the profound impact they have on their surroundings. The huge eruption is seen in a Chandra image of the hot, X-ray emitting gas of a galaxy cluster called MS 0735.6+7421. Two vast cavities extend away from the supermassive black hole in the cluster's central galaxy. The eruption - which has lasted for 100 million years and is still going - has generated the energy equivalent to hundreds of millions of gamma-ray bursts. Animation of Eruption from Supermassive Black Hole Animation of Eruption from Supermassive Black Hole This event was caused by gravitational energy release as enormous amounts of matter fell toward a black hole. Most of the matter was swallowed, but some of it was violently ejected before being captured by the black hole. "I was stunned to find that a mass of about 300 million Suns was swallowed," said Brian McNamara of Ohio University in Athens, lead author of the study that appears in the January 6, 2005 issue of Nature. "This is almost as massive as the supermassive black hole that swallowed it." Astronomers are not sure where such large amounts of matter came from. One theory is that gas from the host galaxy catastrophically cooled and was then swallowed by the black hole. Illustration of MS 0735.6+742 Illustration of MS 0735.6+742 The energy released shows that the black hole in MS 0735 has grown very dramatically during this eruption. Previous studies suggest that other large black holes have grown very little in the recent past, and that only smaller black holes are still growing quickly. "This new result is as surprising as it is exciting", said co-author Paul Nulsen of the Harvard-Smithsonian Center of Astrophysics. "This black hole is feasting when it should be fasting." Radio

  9. Erupted complex composite odontoma: Report of two atypical cases

    Directory of Open Access Journals (Sweden)

    Preeti Tomar Bhattacharya

    2015-01-01

    Full Text Available Odontomas are nonaggressive, hamartomatous developmental malformations of odontogenic origin. They are considered one of the most common odontogenic lesions composed by diverse dental tissues. They may interfere with the eruption of an associated tooth and are more prevalent in the posterior mandible. The eruption of a complex odontoma into the oral cavity is rare. Here, we report such two rare cases of gigantic erupted complex composite odontomas.

  10. Geostationary satellite observations of the april 1979 soufriere eruptions.

    Science.gov (United States)

    Krueger, A F

    1982-06-04

    Infrared images from the geostationary satellite SMS-1 were used to study the growth of the eight major eruptions of Soufriere, St. Vincent, during April 1979. These eruptions differed considerably in growth and intensity, the most intense being that of 17 April which formed an ash cloud of 96,000 square kilometers in 4 hours. The weakest eruption formed a cloud of only 16,000 square kilometers.

  11. Impacts of a Pinatubo-size volcanic eruption on ENSO

    KAUST Repository

    Predybaylo, Evgeniya

    2017-01-16

    Observations and model simulations of the climate responses to strong explosive low-latitude volcanic eruptions suggest a significant increase in the likelihood of El Niño during the eruption and posteruption years, though model results have been inconclusive and have varied in magnitude and even sign. In this study, we test how this spread of responses depends on the initial phase of El Niño-Southern Oscillation (ENSO) in the eruption year and on the eruption\\'s seasonal timing. We employ the Geophysical Fluid Dynamics Laboratory CM2.1 global coupled general circulation model to investigate the impact of the Pinatubo 1991 eruption, assuming that in 1991 ENSO would otherwise be in central or eastern Pacific El Niño, La Niña, or neutral phases. We obtain statistically significant El Niño responses in a year after the eruption for all cases except La Niña, which shows no response in the eastern equatorial Pacific. The eruption has a weaker impact on eastern Pacific El Niños than on central Pacific El Niños. We find that the ocean dynamical thermostat and (to a lesser extent) wind changes due to land-ocean temperature gradients are the main feedbacks affecting El Niño development after the eruption. The El Niño responses to eruptions occurring in summer are more pronounced than for winter and spring eruptions. That the climate response depends on eruption season and initial ENSO phase may help to reconcile apparent inconsistencies among previous studies.

  12. Failed magmatic eruptions: Late-stage cessation of magma ascent

    Science.gov (United States)

    Moran, S.C.; Newhall, C.; Roman, D.C.

    2011-01-01

    When a volcano becomes restless, a primary question is whether the unrest will lead to an eruption. Here we recognize four possible outcomes of a magmatic intrusion: "deep intrusion", "shallow intrusion", "sluggish/viscous magmatic eruption", and "rapid, often explosive magmatic eruption". We define "failed eruptions" as instances in which magma reaches but does not pass the "shallow intrusion" stage, i. e., when magma gets close to, but does not reach, the surface. Competing factors act to promote or hinder the eventual eruption of a magma intrusion. Fresh intrusion from depth, high magma gas content, rapid ascent rates that leave little time for enroute degassing, opening of pathways, and sudden decompression near the surface all act to promote eruption, whereas decreased magma supply from depth, slow ascent, significant enroute degassing and associated increases in viscosity, and impingement on structural barriers all act to hinder eruption. All of these factors interact in complex ways with variable results, but often cause magma to stall at some depth before reaching the surface. Although certain precursory phenomena, such as rapidly escalating seismic swarms or rates of degassing or deformation, are good indicators that an eruption is likely, such phenomena have also been observed in association with intrusions that have ultimately failed to erupt. A perpetual difficulty with quantifying the probability of eruption is a lack of data, particularly on instances of failed eruptions. This difficulty is being addressed in part through the WOVOdat database. Papers in this volume will be an additional resource for scientists grappling with the issue of whether or not an episode of unrest will lead to a magmatic eruption.

  13. Consequences of magma eruption dynamics: Intraflow variations in petrography and mineral chemistry within a single eruptive unit from Whitewater Canyon, Oregon

    Science.gov (United States)

    Ustunisik, G. K.; Nielsen, R. L.

    2012-12-01

    degassed. This is supported by the absence of amphibole phenocrysts in the first erupted, quenched samples. However, the presence of volatiles in glassy melt inclusions and phenocrysts suggests that the system had not completely degassed prior to the eruption. Also, the petrographic heterogeneity of the unit demonstrates that complete overturn and mixing did not happen at Mt. Jefferson. Therefore, eruption may have been triggered by the injection of mafic material; however, the petrographic and field evidence suggests that overturn is not required as part of that triggering event.

  14. The 2012-2014 eruptive cycle of Copahue Volcano, Southern Andes. Magmatic-Hydrothermal system interaction and manifestations.

    Science.gov (United States)

    Morales, Sergio; Alarcón, Alex; Basualto, Daniel; Bengoa, Cintia; Bertín, Daniel; Cardona, Carlos; Córdova, Maria; Franco, Luis; Gil, Fernando; Hernandez, Erasmo; Lara, Luis; Lazo, Jonathan; Mardones, Cristian; Medina, Roxana; Peña, Paola; Quijada, Jonathan; San Martín, Juan; Valderrama, Oscar

    2015-04-01

    deformation of the volcanic edifice detected by GPS network. In this new eruptive process, the record of tremor was followed by particular seismic quiescence, as precursors of explosive activity which evolved from low acoustic energy signals toward more energetic signals with impulsive first arrivals and strong attenuation, joined to night incandescence in the main vent without evident juvenile material ejected, which could be associated to the temporal depression of the hydrothermal system located in the volcano system. The recent eruptive episode at Copahue Volcano is a good example of the complex temporal evolution of the interaction between magmatic and hydrothermal systems.

  15. High-resolution Observations of Sympathetic Filament Eruptions by NVST

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shangwei; Su, Yingna; Zhou, Tuanhui; Ji, Haisheng [Key Laboratory for Dark Matter and Space Science, Purple Mountain Observatory, CAS, Nanjing 210008 (China); Van Ballegooijen, Adriaan [5001 Riverwood Avenue, Sarasota, FL 34231 (United States); Sun, Xudong, E-mail: ynsu@pmo.ac.cn [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2017-07-20

    We investigate two sympathetic filament eruptions observed by the New Vacuum Solar Telescope on 2015 October 15. The full picture of the eruptions is obtained from the corresponding Solar Dynamics Observatory ( SDO )/Atmospheric Imaging Assembly (AIA) observations. The two filaments start from active region NOAA 12434 in the north and end in one large quiescent filament channel in the south. The left filament erupts first, followed by the right filament eruption about 10 minutes later. Clear twist structure and rotating motion are observed in both filaments during the eruption. Both eruptions failed, since the filaments first rise up, then flow toward the south and merge into the southern large quiescent filament. We also observe repeated activations of mini filaments below the right filament after its eruption. Using magnetic field models constructed based on SDO /HMI magnetograms via the flux rope insertion method, we find that the left filament eruption is likely to be triggered by kink instability, while the weakening of overlying magnetic fields due to magnetic reconnection at an X-point between the two filament systems might play an important role in the onset of the right filament eruption.

  16. Beyond eruptive scenarios: assessing tephra fallout hazard from Neapolitan volcanoes.

    Science.gov (United States)

    Sandri, Laura; Costa, Antonio; Selva, Jacopo; Tonini, Roberto; Macedonio, Giovanni; Folch, Arnau; Sulpizio, Roberto

    2016-04-12

    Assessment of volcanic hazards is necessary for risk mitigation. Typically, hazard assessment is based on one or a few, subjectively chosen representative eruptive scenarios, which use a specific combination of eruptive sizes and intensities to represent a particular size class of eruption. While such eruptive scenarios use a range of representative members to capture a range of eruptive sizes and intensities in order to reflect a wider size class, a scenario approach neglects to account for the intrinsic variability of volcanic eruptions, and implicitly assumes that inter-class size variability (i.e. size difference between different eruptive size classes) dominates over intra-class size variability (i.e. size difference within an eruptive size class), the latter of which is treated as negligible. So far, no quantitative study has been undertaken to verify such an assumption. Here, we adopt a novel Probabilistic Volcanic Hazard Analysis (PVHA) strategy, which accounts for intrinsic eruptive variabilities, to quantify the tephra fallout hazard in the Campania area. We compare the results of the new probabilistic approach with the classical scenario approach. The results allow for determining whether a simplified scenario approach can be considered valid, and for quantifying the bias which arises when full variability is not accounted for.

  17. Microbiological characterization of post-eruption "snowblower" vents at Axial Seamount, Juan de Fuca Ridge

    Directory of Open Access Journals (Sweden)

    Julie L Meyer

    2013-06-01

    Full Text Available Microbial processes within the subseafloor can be examined during the ephemeral and uncommonly observed phenomena known as snowblower venting. Snowblowers are characterized by the large quantity of white floc that is expelled from the seafloor following mid-ocean ridge eruptions. During these eruptions, rapidly cooling lava entrains seawater and hydrothermal fluids enriched in geochemical reactants, creating a natural bioreactor that supports a subseafloor microbial bloom. Previous studies hypothesized that the eruption-associated floc is made by sulfide-oxidizing bacteria; however, the microbes involved were never identified. Here we present the first molecular analysis combined with microscopy of microbial communities in snowblower vents from samples collected shortly after the 2011 eruption at Axial Seamount, an active volcano on the Juan de Fuca Ridge. We obtained fluid samples and white flocculent material from active snowblower vents as well as orange flocculent material found on top of newly formed lava flows. Both flocculent types revealed diverse cell types and particulates when examined by phase contrast and scanning electron microscopy. Distinct archaeal and bacterial communities were detected in each sample type through Illumina tag sequencing of 16S rRNA genes and through sequencing of the sulfide oxidation gene, soxB. In fluids and white floc, the dominant bacteria were sulfur-oxidizing Epsilonproteobacteria and the dominant archaea were thermophilic Methanococcales. In contrast, the dominant organisms in the orange floc were Gammaproteobacteria and Thaumarchaeota Marine Group I. In all samples, bacteria greatly outnumbered archaea. The presence of anaerobic methanogens and microaerobic Epsilonproteobacteria in snowblower communities provides evidence that these blooms are seeded by subseafloor microbes, rather than from microbes in bottom seawater. These eruptive events thus provide a unique opportunity to observe subseafloor

  18. Geochemistry and volatile content of magmas feeding explosive eruptions at Telica volcano (Nicaragua)

    Science.gov (United States)

    Robidoux, P.; Rotolo, S. G.; Aiuppa, A.; Lanzo, G.; Hauri, E. H.

    2017-07-01

    Telica volcano, in north-west Nicaragua, is a young stratovolcano of intermediate magma composition producing frequent Vulcanian to phreatic explosive eruptions. The Telica stratigraphic record also includes examples of (pre)historic sub-Plinian activity. To refine our knowledge of this very active volcano, we analyzed major element composition and volatile content of melt inclusions from some stratigraphically significant Telica tephra deposits. These include: (1) the Scoria Telica Superior (STS) deposit (2000 to 200 years Before Present; Volcanic Explosive Index, VEI, of 2-3) and (2) pyroclasts from the post-1970s eruptive cycle (1982; 2011). Based on measurements with nanoscale secondary ion mass spectrometry, olivine-hosted (forsterite [Fo] > 80) glass inclusions fall into 2 distinct clusters: a group of H2O-rich (1.8-5.2 wt%) inclusions, similar to those of nearby Cerro Negro volcano, and a second group of CO2-rich (360-1700 μg/g CO2) inclusions (Nejapa, Granada). Model calculations show that CO2 dominates the equilibrium magmatic vapor phase in the majority of the primitive inclusions (XCO2 > 0.62-0.95). CO2, sulfur (generally 400 MPa) and early crystallization of magmas. Chlorine exhibits a wide concentration range (400-2300 μg/g) in primitive olivine-entrapped melts (likely suggesting variable source heterogeneity) and is typically enriched in the most differentiated melts (1000-3000 μg/g). Primitive, volatile-rich olivine-hosted melt inclusions (entrapment pressures, 5-15 km depth) are exclusively found in the largest-scale Telica eruptions (exemplified by STS in our study). These eruptions are thus tentatively explained as due to injection of deep CO2-rich mafic magma into the shallow crustal plumbing system. More recent (post-1970), milder (VEI 1-2) eruptions, instead, do only exhibit evidence for low-pressure (P viscosity of resident magma in shallow plumbing system (< 2.4 km), due to crystallization and degassing.

  19. Human survival in volcanic eruptions: Thermal injuries in pyroclastic surges, their causes, prognosis and emergency management.

    Science.gov (United States)

    Baxter, Peter J; Jenkins, Susanna; Seswandhana, Rosadi; Komorowski, Jean-Christophe; Dunn, Ken; Purser, David; Voight, Barry; Shelley, Ian

    2017-08-01

    This study of burns patients from two eruptions of Merapi volcano, Java, in 1994 and 2010, is the first detailed analysis to be reported of thermal injuries in a large series of hospitalised victims of pyroclastic surges, one of the most devastating phenomena in explosive eruptions. Emergency planners in volcanic crises in populated areas have to integrate the health sector into disaster management and be aware of the nature of the surge impacts and the types of burns victims to be expected in a worst scenario, potentially in numbers and in severity that would overwhelm normal treatment facilities. In our series, 106 patients from the two eruptions were treated in the same major hospital in Yogyakarta and a third of these survived. Seventy-eight per cent were admitted with over 40% TBSA (total body surface area) burns and around 80% of patients were suspected of having at least some degree of inhalation injury as well. Thirty five patients suffered over 80% TBSA burns and only one of these survived. Crucially, 45% of patients were in the 40-79% TBSA range, with most suspected of suffering from inhalation injury, for whom survival was most dependent on the hospital treatment they received. After reviewing the evidence from recent major eruptions and outlining the thermal hazards of surges, we relate the type and severity of the injuries of these patients to the temperatures and dynamics of the pyroclastic surges, as derived from the environmental impacts and associated eruption processes evaluated in our field surveys and interviews conducted by our multi-disciplinary team. Effective warnings, adequate evacuation measures, and political will are all essential in volcanic crises in populated areas to prevent future catastrophes on this scale. Copyright © 2017 Elsevier Ltd and ISBI. All rights reserved.

  20. The 2003 phreatomagmatic eruptions of Anatahan volcano - Textural and petrologic features of deposits at an emergent island volcano

    Science.gov (United States)

    Pallister, J.S.; Trusdell, F.A.; Brownfield, I.K.; Siems, D.F.; Budahn, J.R.; Sutley, S.F.

    2005-01-01

    Stratigraphic and field data are used in conjunction with textural and chemical evidence (including data from scanning electron microscope, electron microprobe, X-ray fluorescence, X-ray diffraction, and instrumental neutron activation analysis) to establish that the 2003 eruption of Anatahan volcano was mainly phreatomagmatic, dominated by explosive interaction of homogeneous composition low-viscosity crystal-poor andesite magma with water. The hydromagmatic mode of eruption contributed to the significant height of initial eruptive columns and to the excavation and eruption of altered rock debris from the sub-volcanic hydrothermal system. Volatile contents of glass inclusions in equilibrium phenocrysts less abundances of these constituents in matrix glass times the estimated mass of juvenile magma indicate minimum emissions of 19 kt SO2 and 13 kt Cl. This petrologic estimate of SO2 emission is an order-of-magnitude less than an estimate from TOMS. Similarly, inferred magma volumes from the petrologic data are an order of magnitude greater than those modeled from deformation data. Both discrepancies indicate additional sources of volatiles, likely derived from a separate fluid phase in the magma. The paucity of near-source volcanic-tectonic earthquakes preceding the eruption, and the dominance of sustained long-period tremor are attributed to the ease of ascent of the hot low-viscosity andesite, followed by a shallow phreatomagmatic mode of eruption. Phreatomagmatic eruptions are probably more common at emergent tropical island volcanoes, where shallow fresh-water lenses occur at near-sea-level vents. These relations suggest that phreatomagmatic explosions contributed to the formation of many of the near-sea-level craters and possibly even to the small calderas at the other Mariana islands.

  1. Storage, Ascent, and Release of Silicic Magma in Caldera-forming Eruptions

    Science.gov (United States)

    Myers, Madison Logan

    The mechanisms and timescales associated with the triggering of caldera-forming eruptions remain ambiguous and poorly constrained. Do such eruptions start vigorously, then escalate, or can there be episodicity? Are they triggered through internal processes (e.g. recharge, buoyancy), or can external modulations play an important role? Key to answering these questions is the ability to reconstruct the state of the magma body immediately prior to eruption. My dissertation research seeks to answer these questions through detailed investigation of four voluminous caldera-forming eruptions: (1) 650 km3, 0.767 Ma Bishop Tuff, Long Valley, (2) 530 km3, 25.4 ka Oruanui eruption, Taupo, (3) 2,500 km3, 2.08 Ma Huckleberry Ridge Tuff, Yellowstone and (4) 250 km3, 26.91 Ma Cebolla Creek Tuff, Colorado. The main techniques I applied integrated glass geochemistry (major, trace and volatile), diffusion modeling, and detailed field sampling. In chapters two, three, and four these methods are applied to the initial fall deposits of three supereruptions (Bishop, Oruanui and Huckleberry Ridge) that preserve field-evidence for different opening behaviors. These behaviors range from continuous deposition of fall deposits and ignimbrite (Bishop), to repetitive start/stop behavior, with time breaks between eruptive episodes on the order of weeks to months (Oruanui, Huckleberry Ridge). To reconstruct the timescales of opening activity and relate this to conduit processes, I used two methods that exploit diffusion of volatiles through minerals and melt, providing estimates for the rate at which magmas ascended to the surface. This knowledge is then integrated with the pre-eruptive configuration of the magma body, based on melt inclusion chemistry, to interpret what triggered these systems into unrest. Finally, in chapter five I take a different approach by integrating geochemical data for melt inclusions and phenocryst minerals to test whether the mechanism of heat and volatile recharge

  2. Eruptive history, geochronology, and post-eruption structural evolution of the late Eocene Hall Creek Caldera, Toiyabe Range, Nevada

    Science.gov (United States)

    Colgan, Joseph P.; Henry, Christopher D.

    2017-02-24

    years of the main eruption, and for the next approximately 10 million years sedimentary rocks and distal tuffs sourced from calderas farther west ponded in the caldera basin surrounding low areas nearby. Patterns of tuff deposition indicate that the area was characterized by east-west trending paleovalleys and ridges in the late Eocene and Oligocene, which permitted tuffs to disperse east-west but limited their north-south extent. Although a low-angle fault contact of limited extent separates Cambrian and Ordovician strata in the southwestern part of the study area, there is no evidence that this fault cuts overlying Tertiary rocks. Total extensional strain across the caldera is on the order of 15 percent, and there is no evidence for progressive tilting of 34–25 Ma rocks that would indicate protracted Eocene–Oligocene extension. The caldera appears to have been tilted as an intact block after 25 Ma, probably during the middle Miocene extensional faulting well documented to the north and south of the study area.

  3. Stratospheric sulfate from the Gareloi eruption, 1980: Contribution to the ''ambient'' aerosol by a poorly documented volcanic eruption

    International Nuclear Information System (INIS)

    Sedlacek, W.A.; Mroz, E.J.; Heiken, G.

    1981-01-01

    While sampling stratospheric aerosols during July--August 1980 a plume of ''fresh'' volcanic debris was observed in the Northern hemisphere. The origin of this material seems to be a poorly documented explosive eruption of Gareloi valcano in the Aleutian Islands. The debris was sampled at an altitude of 19.2 km: almost twice the height of observed eruption clouds. Such remote, unobserved or poorly documented eruptions may be a source that helps maintain the ''ambient'' stratospheric aerosol background

  4. Sunspot splitting triggering an eruptive flare

    Science.gov (United States)

    Louis, Rohan E.; Puschmann, Klaus G.; Kliem, Bernhard; Balthasar, Horst; Denker, Carsten

    2014-02-01

    Aims: We investigate how the splitting of the leading sunspot and associated flux emergence and cancellation in active region NOAA 11515 caused an eruptive M5.6 flare on 2012 July 2. Methods: Continuum intensity, line-of-sight magnetogram, and dopplergram data of the Helioseismic and Magnetic Imager were employed to analyse the photospheric evolution. Filtergrams in Hα and He I 10830 Å of the Chromospheric Telescope at the Observatorio del Teide, Tenerife, track the evolution of the flare. The corresponding coronal conditions were derived from 171 Å and 304 Å images of the Atmospheric Imaging Assembly. Local correlation tracking was utilized to determine shear flows. Results: Emerging flux formed a neutral line ahead of the leading sunspot and new satellite spots. The sunspot splitting caused a long-lasting flow towards this neutral line, where a filament formed. Further flux emergence, partly of mixed polarity, as well as episodes of flux cancellation occurred repeatedly at the neutral line. Following a nearby C-class precursor flare with signs of interaction with the filament, the filament erupted nearly simultaneously with the onset of the M5.6 flare and evolved into a coronal mass ejection. The sunspot stretched without forming a light bridge, splitting unusually fast (within about a day, complete ≈6 h after the eruption) in two nearly equal parts. The front part separated strongly from the active region to approach the neighbouring active region where all its coronal magnetic connections were rooted. It also rotated rapidly (by 4.9° h-1) and caused significant shear flows at its edge. Conclusions: The eruption resulted from a complex sequence of processes in the (sub-)photosphere and corona. The persistent flows towards the neutral line likely caused the formation of a flux rope that held the filament. These flows, their associated flux cancellation, the emerging flux, and the precursor flare all contributed to the destabilization of the flux rope. We

  5. Eruptive history of Mount Katmai, Alaska

    Science.gov (United States)

    Hildreth, Edward; Fierstein, Judith

    2012-01-01

    Mount Katmai has long been recognized for its caldera collapse during the great pyroclastic eruption of 1912 (which vented 10 km away at Novarupta in the Valley of Ten Thousand Smokes), but little has previously been reported about the geology of the remote ice-clad stratovolcano itself. Over several seasons, we reconnoitered all parts of the edifice and sampled most of the lava flows exposed on its flanks and caldera rim. The precipitous inner walls of the 1912 caldera remain too unstable for systematic sampling; so we provide instead a photographic and interpretive record of the wall sequences exposed. In contrast to the several andesite-dacite stratovolcanoes nearby, products of Mount Katmai range from basalt to rhyolite. Before collapse in 1912, there were two overlapping cones with separate vent complexes and craters; their products are here divided into eight sequences of lava flows, agglutinates, and phreatomagmatic ejecta. Latest Pleistocene and Holocene eruptive units include rhyodacite and rhyolite lava flows along the south rim; a major 22.8-ka rhyolitic plinian fall and ignimbrite deposit; a dacite-andesite zoned scoria fall; a thick sheet of dacite agglutinate that filled a paleocrater and draped the west side of the edifice; unglaciated leveed dacite lava flows on the southeast slope; and the Horseshoe Island dacite dome that extruded on the caldera floor after collapse. Pre-collapse volume of the glaciated Katmai edifice was ∼30 km3, and eruptive volume is estimated to have been 57±13 km3. The latter figure includes ∼40±6 km3 for the edifice, 5±2 km3 for off-edifice dacite pyroclastic deposits, and 12±5 km3 for the 22.8-ka rhyolitic pyroclastic deposits. To these can be added 13.5 km3 of magma that erupted at Novarupta in 1912, all or much of which is inferred to have been withdrawn from beneath Mount Katmai. The oldest part of the edifice exposed is a basaltic cone, which gave a 40Ar/39Ar plateau age of 89 ± 25 ka.

  6. Fluid flow modeling at the Lusi mud eruption, East java, Indonesia.

    Science.gov (United States)

    Collignon, Marine; Schmid, Daniel; Mazzini, Adriano

    2016-04-01

    The 29th of may 2006, gas water and mud breccia started to erupt at several localities along the Watukosek fault system, in the Sidoarjo Regency in East java, Indonesia. The most prominent eruption, named Lusi, is still active and covering a surface of nearly 7 km2, resulting in the displacement of ~ 30 000 people. Although the origin and the chemical composition of the erupted fluids have been documented, the mechanical and physical properties of the mud are poorly constrained, and many aspects still remain not understood. Very little is known about the internal dynamics of the Lusi conduit(s). In this study, conducted in the framework of the Lusi Lab project (ERC grant n°308126) we use both analytical and numerical methods to better understand the flow dynamics within the main conduit and to try to explain the longevity of the edifice. The 2D numerical model considers a vertical conduit with a reservoir at its base and solves the stokes equations, discretized on a finite element mesh. Although, three phases (solid, liquid and gas) are present in nature, we only consider the liquid phase. The solid phase is treated as rigid particles in suspension in the liquid. The gaseous phase (methane and carbon dioxide) is treated in an analytical manner using the equations of state of the H2O-CO2 and H2O-CH4 systems. Here, we discuss the effects of density, viscosity, gas concentration and clasts concentration and size on the dynamics of the flow in the conduit as well as implications of the conduit stability.

  7. Elastic energy release in great earthquakes and eruptions

    Directory of Open Access Journals (Sweden)

    Agust eGudmundsson

    2014-05-01

    Full Text Available The sizes of earthquakes are measured using well-defined, measurable quantities such as seismic moment and released (transformed elastic energy. No similar measures exist for the sizes of volcanic eruptions, making it difficult to compare the energies released in earthquakes and eruptions. Here I provide a new measure of the elastic energy (the potential mechanical energy associated with magma chamber rupture and contraction (shrinkage during an eruption. For earthquakes and eruptions, elastic energy derives from two sources: (1 the strain energy stored in the volcano/fault zone before rupture, and (2 the external applied load (force, pressure, stress, displacement on the volcano/fault zone. From thermodynamic considerations it follows that the elastic energy released or transformed (dU during an eruption is directly proportional to the excess pressure (pe in the magma chamber at the time of rupture multiplied by the volume decrease (-dVc of the chamber, so that . This formula can be used as a basis for a new eruption magnitude scale, based on elastic energy released, which can be related to the moment-magnitude scale for earthquakes. For very large eruptions (>100 km3, the volume of the feeder-dike is negligible, so that the decrease in chamber volume during an eruption corresponds roughly to the associated volume of erupted materials , so that the elastic energy is . Using a typical excess pressures of 5 MPa, it is shown that the largest known eruptions on Earth, such as the explosive La Garita Caldera eruption (27-28 million years ago and largest single (effusive Colombia River basalt lava flows (15-16 million years ago, both of which have estimated volumes of about 5000 km3, released elastic energy of the order of 10EJ. For comparison, the seismic moment of the largest earthquake ever recorded, the M9.5 1960 Chile earthquake, is estimated at 100 ZJ and the associated elastic energy release at 10EJ.

  8. The Novarupta-Katmai eruption of 1912 - largest eruption of the twentieth century; centennial perspectives

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2012-01-01

    The explosive outburst at Novarupta (Alaska) in June 1912 was the 20th century's most voluminous volcanic eruption. Marking its centennial, we illustrate and document the complex eruptive sequence, which was long misattributed to nearby Mount Katmai, and how its deposits have provided key insights about volcanic and magmatic processes. It was one of the few historical eruptions to produce a collapsed caldera, voluminous high-silica rhyolite, wide compositional zonation (51-78 percent SiO2), banded pumice, welded tuff, and an aerosol/dust veil that depressed global temperature measurably. It emplaced a series of ash flows that filled what became the Valley of Ten Thousand Smokes, sustaining high-temperature metal-transporting fumaroles for a decade. Three explosive episodes spanned ~60 hours, depositing ~17 km3 of fallout and 11±2 km3 of ignimbrite, together representing ~13.5 km3 of zoned magma. No observers were nearby and no aircraft were in Alaska, and so the eruption narrative was assembled from scattered villages and ship reports. Because volcanology was in its infancy and the early investigations (1915-23) were conducted under arduous expeditionary conditions, many provocative misapprehensions attended reports based on those studies. Fieldwork at Katmai was not resumed until 1953, but, since then, global advances in physical volcanology and chemical petrology have gone hand in hand with studies of the 1912 deposits, clarifying the sequence of events and processes and turning the eruption into one of the best studied in the world. To provide perspective on this century-long evolution, we describe the geologic and geographic setting of the eruption - in a remote, sparsely inhabited wilderness; we review the cultural and scientific contexts at the time of the eruption and early expeditions; and we compile a chronology of the many Katmai investigations since 1912. Products of the eruption are described in detail, including eight layers of regionwide fallout

  9. Thallium as a tracer for preindustrial volcanic eruptions in an ice core record from Illimani, Bolivia.

    Science.gov (United States)

    Kellerhals, Thomas; Tobler, Leonhard; Brütsch, Sabina; Sigl, Michael; Wacker, Lukas; Gäggeler, Heinz W; Schwikowski, Margit

    2010-02-01

    Trace element records from glacier and ice sheet archives provide insights into biogeochemical cycles, atmospheric circulation changes, and anthropogenic pollution history. We present the first continuous high-resolution thallium (Tl) record, derived from an accurately dated ice core from tropical South America, and discuss Tl as a tracer for volcanic eruptions. We identify four prominent Tl peaks and propose that they represent signals from the massive explosive eruptions of the "unknown 1258" A.D. volcano, of Kuwae ( approximately 1450 A.D.), Tambora (1815 A.D.), and Krakatoa (1883 A.D.). The highly resolved record was obtained with an improved setup for the continuous analysis of trace elements in ice with inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The new setup allowed for a stronger initial acidification of the meltwater and shorter tubing length, thereby reducing the risk of memory effects and losses of analytes to the capillary walls. With a comparison of the continuous method to the established conventional decontamination and analysis procedure for discrete samples, we demonstrate the accuracy of the continuous method for Tl analyses.

  10. Tic Tac TOE: Effects of Predictability and Importance on Acoustic Prominence in Language Production

    Science.gov (United States)

    Watson, Duane G.; Arnold, Jennifer E.; Tanenhaus, Michael K.

    2008-01-01

    Importance and predictability each have been argued to contribute to acoustic prominence. To investigate whether these factors are independent or two aspects of the same phenomenon, naive participants played a verbal variant of Tic Tac Toe. Both importance and predictability contributed independently to the acoustic prominence of a word, but in…

  11. 77 FR 3779 - Guidance for Industry on Product Name Placement, Size, and Prominence in Advertising and...

    Science.gov (United States)

    2012-01-25

    ... Advertising and Promotional Labeling; Availability AGENCY: Food and Drug Administration, HHS. ACTION: Notice... entitled ``Product Name Placement, Size, and Prominence in Advertising and Promotional Labeling.'' The..., prominence, and frequency in promotional labeling and advertising for prescription human and animal drugs and...

  12. Eruptive history and geochronology of Mount Mazama and the Crater Lake region, Oregon

    Science.gov (United States)

    Bacon, Charles R.; Lanphere, Marvin A.

    2006-01-01

    Geologic mapping, K-Ar, and 40Ar/39Ar age determinations, supplemented by paleomagnetic measurements and geochemical data, are used to quantify the Quaternary volcanic history of the Crater Lake region in order to define processes and conditions that led to voluminous explosive eruptions. The Cascade arc volcano known as Mount Mazama collapsed during its climactic eruption of ∼50 km3 of mainly rhyodacitic magma ∼7700 yr ago to form Crater Lake caldera. The Mazama edifice was constructed on a Pleistocene silicic lava field, amidst monogenetic and shield volcanoes ranging from basalt to andesite similar to parental magmas for Mount Mazama. Between 420 ka and 35 ka, Mazama produced medium-K andesite and dacite in 2:1 proportion. The edifice was built in many episodes; some of the more voluminous occurred approximately coeval with volcanic pulses in the surrounding region, and some were possibly related to deglaciation following marine oxygen isotope stages (MIS) 12, 10, 8, 6, 5.2, and 2. Magmas as evolved as dacite erupted many times, commonly associated with or following voluminous andesite effusion. Establishment of the climactic magma chamber was under way when the first preclimactic rhyodacites vented ca. 27 ka. The silicic melt volume then grew incrementally at an average rate of 2.5 km3 k.y.−1 for nearly 20 k.y. The climactic eruption exhausted the rhyodacitic magma and brought up crystal-rich andesitic magma, mafic cumulate mush, and wall-rock granodiorite. Postcaldera volcanism produced 4 km3 of andesite during the first 200–500 yr after collapse, followed at ca. 4800 yr B.P. by 0.07 km3 of rhyodacite. The average eruption rate for all Mazama products was ∼0.4 km3 k.y.−1, but major edifice construction episodes had rates of ∼0.8 km3 k.y.−1. The long-term eruption rate for regional monogenetic and shield volcanoes was d∼0.07 km3 k.y.−1, but only ∼0.02 km3 k.y.−1 when the two major shields are excluded. Plutonic xenoliths and evidence for

  13. Supercomputer modeling of volcanic eruption dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Kieffer, S.W. [Arizona State Univ., Tempe, AZ (United States); Valentine, G.A. [Los Alamos National Lab., NM (United States); Woo, Mahn-Ling [Arizona State Univ., Tempe, AZ (United States)

    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.

  14. Magnetic reconnection during eruptive magnetic flux ropes

    Science.gov (United States)

    Mei, Z. X.; Keppens, R.; Roussev, I. I.; Lin, J.

    2017-08-01

    Aims: We perform a three-dimensional (3D) high resolution numerical simulation in isothermal magnetohydrodynamics to study the magnetic reconnection process in a current sheet (CS) formed during an eruption of a twisted magnetic flux rope (MFR). Because the twist distribution violates the Kruskal-Shafranov condition, the kink instability occurs, and the MFR is distorted. The centre part of the MFR loses its equilibrium and erupts upward, which leads to the formation of a 3D CS underneath it. Methods: In order to study the magnetic reconnection inside the CS in detail, mesh refinement has been used to reduce the numerical diffusion and we estimate a Lundquist number S = 104 in the vicinity of the CS. Results: The refined mesh allows us to resolve fine structures inside the 3D CS: a bifurcating sheet structure signaling the 3D generalization of Petschek slow shocks, some distorted-cylindrical substructures due to the tearing mode instabilities, and two turbulence regions near the upper and the lower tips of the CS. The topological characteristics of the MFR depend sensitively on the observer's viewing angle: it presents as a sigmoid structure, an outwardly expanding MFR with helical distortion, or a flare-CS-coronal mass ejection symbiosis as in 2D flux-rope models when observed from the top, the front, or the side. The movie associated to Fig. 2 is available at http://www.aanda.org

  15. Fixed Drug Eruption due to Achiote Dye

    Directory of Open Access Journals (Sweden)

    Ian Tattersall

    2016-01-01

    Full Text Available Fixed drug eruption (FDE is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing.

  16. Fixed Drug Eruption due to Achiote Dye

    Science.gov (United States)

    Tattersall, Ian; Reddy, Bobby Y.

    2016-01-01

    Fixed drug eruption (FDE) is a localized type IV sensitivity reaction to a systemically introduced allergen. It usually occurs as a result of new medication, making identification and avoidance of the trigger medication straightforward; however, in a rare subset of cases no pharmacological source is identified. In such cases, the causative agent is often a food or food additive. In this report we describe a case of a FDE in a 12-year-old girl recently immigrated to the United States from Ecuador who had no medication exposure over the course of her illness. Through an exhaustive patient history and literature review, we were able to hypothesize that her presentation was caused by a dietary change of the natural achiote dye used in the preparation of yellow rice to a locally available commercial dye mix containing tartrazine, or Yellow 5, which has previously been implicated in both systemic hypersensitivity reactions and specifically in FDE. This report adds to the small body of available literature on non-pharmacological fixed hypersensitivity eruptions and illustrates an effective approach to the management of such a presentation when history is not immediately revealing. PMID:26933409

  17. From Mush to Eruption in 1000 Years: Rapid Assembly of the Super-Sized Oruanui Magma Body

    Science.gov (United States)

    Allan, A. S.; Morgan, D. J.; Wilson, C. J.; Millet, M.

    2012-12-01

    The mush model is useful in explaining how large volumes of evolved silicic melt can be generated in and extracted from a crystal-rich source to form crystal-poor rhyolite magma bodies at shallow crustal levels. It is unclear, however, how processes of melt extraction and/or formation of the melt-dominant magma body might be reflected in the crystal record, and what physical and temporal constraints can be applied. Textural observations and in situ geochemical fingerprints in crystals from pumices of the ~25.4 ka Oruanui eruption (Taupo, New Zealand), offer new perspectives on the processes, physical conditions and timing of the melt extraction and accumulation. Almost all orthopyroxene (opx) and plagioclase (plag) cores have textures showing a period of disequilibrium (partial dissolution and/or resorption) followed by stable conditions (infilling of raddled cores; euhedral rim overgrowths). Trace element contents in amphibole (amph), which was stable and actively crystallizing in all but the most evolved parcels of Oruanui magma, complement textural evidence showing that Mn and Zn liberated by opx dissolution were preferentially sequestered in amph. Concentrations of these opx-loving elements show a prominent inflection when plotted against indices of melt evolution (e.g. Eu/Eu* in amph) marking a return to opx stability and subsequent crystallization. Plagioclase, the most abundant crystal phase, records a more complex history with significant inheritance, but textural and chemical evidence suggests that at least some of Oruanui plag crystals experienced the same departure from and return to stability as the opx. Amphibole trace element data are linked to in situ estimates of P-T-fO2 and melt H2O determined via the Ridolfi et al. (2010: Contrib Mineral Petrol 160, 45) thermobarometer. Textural and geochemical evidence combined with P-T-H2O model values indicate that three major Oruanui crystal phases (opx, amph, plag) record a significant decompression event

  18. Physics of Solar Prominences: I-Spectral Diagnostics and Non-LTE Modelling

    Science.gov (United States)

    Labrosse, N.; Heinzel, P.; Vial, J.-C,; Kucera, T.; Parenti, S.; Gunar, S.; Schmieder, B.; Kilper, G.

    2010-01-01

    This review paper outlines background information and covers recent advances made via the analysis of spectra and images of prominence plasma and the increased sophistication of non-LTE (i.e. when there is a departure from Local Thermodynamic Equilibrium) radiative transfer models. We first describe the spectral inversion techniques that have been used to infer the plasma parameters important for the general properties of the prominence plasma in both its cool core and the hotter prominence-corona transition region. We also review studies devoted to the observation of bulk motions of the prominence plasma and to the determination of prominence mass. However, a simple inversion of spectroscopic data usually fails when the lines become optically thick at certain wavelengths. Therefore, complex

  19. Fabrication of micro-prominences on PTFE surface using proton beam writing

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Akane, E-mail: ogawa.akane@jaea.go.jp [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Satoh, Takahiro; Koka, Masashi [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan); Kobayashi, Tomohiro [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 350-0198 (Japan); Kamiya, Tomihiro [Department of Advanced Radiation Technology, Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-Machi, Takasaki, Gunma 370-1292 (Japan)

    2013-07-01

    Polytetrafluoroethylene (PTFE) is a typical fluoropolymer and it has several desirable technological properties such as electrical insulation, solid lubrication etc. However, the conventional microstructuring methods have not been well applied to PTFE due to its chemical inertness. Some effective micromachining using synchrotron radiation or ion beam irradiation has been reported. In this study, we create micro-prominences by raising the original surface using proton beam writing (PBW) without chemical etching. A conical prominence was formed by spiral drawing from the center with a 3 MeV proton beam. The body was porous, and the bulk PTFE below the prominence changed to fragmented structures. With decreasing writing speed, the prominence became taller but the height peaked. The prominence gradually reduced in size after the speed reached the optimum value. We expect that these porous projections with high aspect ratio will be versatile in medical fields and microelectromechanical systems (MEMS) technology.

  20. Modeling of prominence threads in magnetic fields: Levitation by incompressible MHD waves

    Science.gov (United States)

    Pécseli, Hans; Engvold, OddbjØrn

    2000-05-01

    The nature of thin, highly inclined threads observed in quiescent prominences has puzzled solar physicists for a long time. When assuming that the threads represent truly inclined magnetic fields, the supporting mechanism of prominence plasma against gravity has remained an open issue. This paper examines the levitation of prominence plasma exerted by weakly damped MHD waves in nearly vertical magnetic flux tubes. It is shown that the wave damping, and resulting `radiation pressure', caused predominantly by ion-neutral collisions in the `cold' prominence plasma, may balance the acceleration of gravity provided the oscillation frequency is ω~ 2 rad s^-1 (f~0.5 Hz). Such short wave periods may be the result of small-scale magnetic reconnections in the highly fragmentary magnetic field of quiescent prominences. In the proposed model, the wave induced levitation acts predominantly on plasma - neutral gas mixtures.

  1. Paradoxical aging in HIV: immune senescence of B Cells is most prominent in young age

    Science.gov (United States)

    George, Varghese K.; de Armas, Lesley R.; Pahwa, Rajendra; Sanchez, Celeste M.; Pallin, Maria Fernanda; Pan, Li; Cotugno, Nicola; Dickinson, Gordon; Rodriguez, Allan; Fischl, Margaret; Alcaide, Maria; Gonzalez, Louis; Palma, Paolo; Pahwa, Savita

    2017-01-01

    Combination antiretroviral therapies (cART) can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative “healthy controls” (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (<40 yrs), middle-aged (40-59yrs) or old (≥60 yrs). H1N1 antibody response at d21 post-vaccination correlated inversely with age in both HC and HIV. Immunophenotyping of cryopreserved PBMC demonstrated increased frequencies of double negative B cells and decreased plasmablasts in old compared to young HC. Remarkably, young HIV were different from young HC but similar to old HC in B cell phenotype, influenza specific spontaneous (d7) or memory (d21) antibody secreting cells. We conclude that B cell immune senescence is a prominent phenomenon in young HIV in comparison to young HC, but distinctions between old HIV and old HC are less evident though both groups manifest age-associated B cell dysfunction. PMID:28448963

  2. Paradoxical aging in HIV: immune senescence of B Cells is most prominent in young age.

    Science.gov (United States)

    Rinaldi, Stefano; Pallikkuth, Suresh; George, Varghese K; de Armas, Lesley R; Pahwa, Rajendra; Sanchez, Celeste M; Pallin, Maria Fernanda; Pan, Li; Cotugno, Nicola; Dickinson, Gordon; Rodriguez, Allan; Fischl, Margaret; Alcaide, Maria; Gonzalez, Louis; Palma, Paolo; Pahwa, Savita

    2017-04-01

    Combination antiretroviral therapies (cART)can lead to normal life expectancy in HIV-infected persons, and people aged >50 yrs represent the fastest growing HIV group. Although HIV and aging are independently associated with impaired humoral immunity, immune status in people aging with HIV is relatively unexplored. In this study influenza vaccination was used to probe age associated perturbations in the B cell compartment of HIV-negative "healthy controls" (HC) and virologically controlled HIV-infected participants on cART (HIV) (n=124), grouped by age as young (aged (40-59yrs) or old ( > 60 yrs). H1N1 antibody response at d21 post-vaccination correlated inversely with age in both HC and HIV. Immunophenotyping of cryopreserved PBMC demonstrated increased frequencies of double negative B cells and decreased plasmablasts in old compared to young HC. Remarkably, young HIV were different from young HC but similar to old HC in B cell phenotype, influenza specific spontaneous (d7) or memory (d21) antibody secreting cells. We conclude that B cell immune senescence is a prominent phenomenon in young HIV in comparison to young HC, but distinctions between old HIV and old HC are less evident though both groups manifest age-associated B cell dysfunction.

  3. Point-of-Sale Tobacco Advertising Remains Prominent in Mumbai, India.

    Science.gov (United States)

    Khariwala, Samir S; Garg, Apurva; Stepanov, Irina; Gupta, Prakash C; Ahluwalia, Jasjit S; Gota, Vikram; Chaturvedi, Pankaj

    2016-07-01

    In India, a 2003 law ("COPTA") banned tobacco advertising with the exception of "point of sale" and "on-pack" advertising. Given substantial evidence regarding the impact of point of sale advertising (PoS), we analyzed the prevalence of encountering such advertising in Mumbai, India. A survey was conducted of 199 current and recent former tobacco users recruited at the Tata Memorial Hospital (Mumbai). Enrollees were queried regarding their exposure to tobacco advertising in the last 30 days through multiple media sources. Descriptive epidemiologic techniques were used to characterize the data. Overall, 95% of participants were men and 5% were women (mean age=49 years). All were current tobacco users or quit using all forms of tobacco in the last 60 days. Participants' responses revealed that PoS tobacco advertising had been encountered in the last 30 days for cigarettes (61%), bidis (54%), and smokeless tobacco (59%). Other forms of tobacco advertising were virtually non-existent. PoS tobacco advertising remains prominent and highly visible to consumers in Mumbai, India, indicating corporate exploitation of a loophole in the COPTA legislation. Given the observed compliance with the currently imposed bans, revisions of COPTA to include all forms of tobacco promotion and advertising would be impactful.

  4. Prominent Midlatitude Circulation Signature in High Asia's Surface Climate During Monsoon

    Science.gov (United States)

    Mölg, Thomas; Maussion, Fabien; Collier, Emily; Chiang, John C. H.; Scherer, Dieter

    2017-12-01

    High Asia has experienced strong environmental changes in recent decades, as evident in records of glaciers, lakes, tree rings, and vegetation. The multiscale understanding of the climatic drivers, however, is still incomplete. In particular, few systematic assessments have evaluated to what degree, if at all, the midlatitude westerly circulation modifies local surface climates in the reach of the Indian Summer Monsoon. This paper shows that a southward shift of the upper-tropospheric westerlies contributes significantly to climate variability in the core monsoon season (July-September) by two prominent dipole patterns at the surface: cooling in the west of High Asia contrasts with warming in the east, while moist anomalies in the east and northwest occur with drying along the southwestern margins. Circulation anomalies help to understand the dipoles and coincide with shifts in both the westerly wave train and the South Asian High, which imprint on air mass advection and local energy budgets. The relation of the variabilities to a well-established index of midlatitude climate dynamics allows future research on climate proxies to include a fresh hypothesis for the interpretation of environmental changes.

  5. The submarine volcano eruption off El Hierro Island: Effects on the scattering migrant biota and the evolution of the pelagic communities

    KAUST Repository

    Ariza, Alejandro

    2014-07-21

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. © 2014 Ariza et al.

  6. Small-scale eruptive filaments on the quiet sun

    International Nuclear Information System (INIS)

    Hermans, L.M.; Martin, S.F.

    1986-01-01

    A study of a little known class of eruptive events on the quiet sun was conducted. All of 61 small-scale eruptive filamentary structures were identified in a systematic survey of 32 days of H alpha time-lapse films of the quiet sun acquired at Big Bear Solar Observatory. When fully developed, these structures have an average length of 15 arc seconds before eruption. They appear to be the small-scale analog of large-scale eruptive filaments observed against the disk. At the observed rate of 1.9 small-scale eruptive features per field of view per average 7.0 hour day, the rate of occurence of these events on the sun were estimated to be greater than 600 per 24 hour day.. The average duration of the eruptive phase was 26 minutes while the average lifetime from formation through eruption was 70 minutes. A majority of the small-scale filamentary sturctures were spatially related to cancelling magnetic features in line-of-sight photospheric magnetograms. Similar to large-scale filaments, the small-scale filamentary structures sometimes divided opposite polarity cancelling fragments but often had one or both ends terminating at a cancellation site. Their high numbers appear to reflect the much greater flux on the quiet sun. From their characteristics, evolution, and relationship to photospheric magnetic flux, it was concluded that the structures described are small-scale eruptive filaments and are a subset of all filaments

  7. Requirement of alveolar bone formation for eruption of rat molars

    Science.gov (United States)

    Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

    2011-01-01

    Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth. PMID:21896048

  8. Accelerated tooth eruption in children with diabetes mellitus.

    Science.gov (United States)

    Lal, Shantanu; Cheng, Bin; Kaplan, Selma; Softness, Barney; Greenberg, Ellen; Goland, Robin S; Lalla, Evanthia; Lamster, Ira B

    2008-05-01

    The objective of this study was to evaluate tooth eruption in 6- to 14-year-old children with diabetes mellitus. Tooth eruption status was assessed for 270 children with diabetes and 320 control children without diabetes. Data on important diabetes-related variables were collected. Analyses were performed using logistic regression models. Children with diabetes exhibited accelerated tooth eruption in the late mixed dentition period (10-14 years of age) compared to healthy children. For both case patients and control subjects the odds of a tooth being in an advanced eruptive stage were significantly higher among girls than boys. There was also a trend associating gingival inflammation with expedited tooth eruption in both groups. No association was found between the odds of a tooth being in an advanced stage of eruption and hemoglobin A(1c) or duration of diabetes. Patients with higher body mass index percentile demonstrated statistically higher odds for accelerated tooth eruption, but the association was not clinically significant. Children with diabetes exhibit accelerated tooth eruption. Future studies need to ascertain the role of such aberrations in dental development and complications such as malocclusion, impaired oral hygiene, and periodontal disease. The standards of care for children with diabetes should include screening and referral programs aimed at oral health promotion and disease prevention.

  9. Mount St. Helens: Still erupting lessons 31 years later

    Science.gov (United States)

    Rhonda Mazza; Charlie Crisafulli; Fred Swanson

    2011-01-01

    The massive volcanic eruption of Mount St. Helens 31 years ago provided the perfect backdrop for studying the earliest stages of forest development. Immediately after the eruption, some areas of the blast area were devoid of life. On other parts of the volcanic landscape, many species survived, although their numbers were greatly reduced. Reassembly began at many...

  10. Interdisciplinary studies of eruption at Chaiten Volcano, Chile

    Science.gov (United States)

    John S. Pallister; Jon J. Major; Thomas C. Pierson; Richard P. Hoblitt; Jacob B. Lowenstern; John C. Eichelberger; Lara. Luis; Hugo Moreno; Jorge Munoz; Jonathan M. Castro; Andres Iroume; Andrea Andreoli; Julia Jones; Fred Swanson; Charlie Crisafulli

    2010-01-01

    There was keen interest within the volcanology community when the first large eruption of high-silica rhyolite since that of Alaska's Novarupta volcano in 1912 began on 1 May 2008 at Chaiten volcano, southern Chile, a 3-kilometer-diameter caldera volcano with a prehistoric record of rhyolite eruptions. Vigorous explosions occurred through 8 May 2008, after which...

  11. Triggering of the largest Deccan eruptions by the Chicxulub impact

    NARCIS (Netherlands)

    Richards, M.A.; Alvarez, W.; Self, S.; Karlstrom, L.; Renne, P.R.; Manga, M.; Sprain, C.J.; Smit, J.; Vanderkluysen, L.; Gibson, S.A.

    2015-01-01

    New constraints on the timing of the Cretaceous- Paleogene mass extinction and the Chicxulub impact, together with a particularly voluminous and apparently brief eruptive pulse toward the end of the "main-stage" eruptions of the Deccan continental flood basalt province suggest that these three

  12. Rapid laccolith intrusion driven by explosive volcanic eruption.

    Science.gov (United States)

    Castro, Jonathan M; Cordonnier, Benoit; Schipper, C Ian; Tuffen, Hugh; Baumann, Tobias S; Feisel, Yves

    2016-11-23

    Magmatic intrusions and volcanic eruptions are intimately related phenomena. Shallow magma intrusion builds subsurface reservoirs that are drained by volcanic eruptions. Thus, the long-held view is that intrusions must precede and feed eruptions. Here we show that explosive eruptions can also cause magma intrusion. We provide an account of a rapidly emplaced laccolith during the 2011 rhyolite eruption of Cordón Caulle, Chile. Remote sensing indicates that an intrusion began after eruption onset and caused severe (>200 m) uplift over 1 month. Digital terrain models resolve a laccolith-shaped body ∼0.8 km 3 . Deformation and conduit flow models indicate laccolith depths of only ∼20-200 m and overpressures (∼1-10 MPa) that likely stemmed from conduit blockage. Our results show that explosive eruptions may rapidly force significant quantities of magma in the crust to build laccoliths. These iconic intrusions can thus be interpreted as eruptive features that pose unique and previously unrecognized volcanic hazards.

  13. Erupting complex odontoma: Report of a rare case

    Directory of Open Access Journals (Sweden)

    Pinakapani Ramakrishna

    2014-01-01

    Full Text Available Odontomas are the most frequent hamartomatous lesions involving the oral cavity. The complex variant is an agglomerate of all dental tissues characterized by abnormal morphodifferentiation despite normal histodifferentiation. These are usually asymptomatic and are frequently associated with eruption disturbances. We report an unusual case of erupting complex odontoma associated with an impacted maxillary second molar.

  14. Stress field control during large caldera-forming eruptions

    Directory of Open Access Journals (Sweden)

    Antonio Costa

    2016-10-01

    Full Text Available Crustal stress field can have a significant influence on the way magma is channelled through the crust and erupted explosively at the surface. Large Caldera Forming Eruptions (LCFEs can erupt hundreds to thousands of cubic kilometres of magma in a relatively short time along fissures under the control of a far-field extensional stress. The associated eruption intensities are estimated in the range 109 - 1011 kg/s. We analyse syn-eruptive dynamics of LCFEs, by simulating numerically explosive flow of magma through a shallow dyke conduit connected to a magma chamber that in turn is fed by a deeper magma reservoir, both under the action of an extensional far-field stress. Results indicate that huge amounts of high viscosity silicic magma can be erupted over timescales of a few to several hours. Our study provides answers to outstanding questions relating to the intensity and duration of catastrophic volcanic eruptions in the past. In addition, it presents far-reaching implications for the understanding of dynamics and intensity of large-magnitude volcanic eruptions on Earth and to highlight the necessity of a future research to advance our knowledge of these rare catastrophic events.

  15. The chemically zoned 1949 eruption on La Palma (Canary Islands): Petrologic evolution and magma supply dynamics of a rift zone eruption

    OpenAIRE

    Klügel, Andreas; Hoernle, Kaj A.; Schmincke, Hans-Ulrich; White, James D. L.

    2000-01-01

    The 1949 rift zone eruption along the Cumbre Vieja ridge on La Palma involved three eruptive centers, 3 km spaced apart, and was chemically and mineralogically zoned. Duraznero crater erupted tephrite for 14 days and shut down upon the opening of Llano del Banco, a fissure that issued first tephrite and, after 3 days, basanite. Hoyo Negro crater opened 4 days later and erupted basanite, tephrite, and phonotephrite, while Llano del Banco continued to issue basanite. The eruption ended with Dur...

  16. Textural constraints on the dynamics of the 2000 Miyakejima eruption

    Science.gov (United States)

    Garozzo, Ileana; Romano, Claudia; Giordano, Guido; Geshi, Nobuo; Vona, Alessandro

    2016-04-01

    Miyakejima Volcano is a basaltic-andesite stratovolcano active from ~10.000 years, located on the north of the Izu-Bonin arc. During the last 600 years the volcano has been characterized mainly by flank fissure activity, with explosive phreatomagmatic eruptions on the coastal areas. In the last century, the activity became more frequent and regular with intervals of 20 to 70 years (1940, 1962, 1983 and 2000). The last activity started on 27 June 2000, with a minor submarine eruption on the west coast of the volcano, and proceeded with six major summit eruptions from July 8 to August 29. The eruptions led to the formation of a collapse caldera ~1.6 km across. The total erupted tephra represents only 1.7% in volume of the caldera, the high fragmentation of magma produced mainly fine-grained volcanic ash. In order to improve the understanding on the triggering and dynamics of this explosive eruption, we carried out a detailed investigation of the erupted materials with particular attention to the textural features of juvenile pyroclasts (Vesicle and Crystal Size Distributions). The stratigraphic record can be divided into six fall units, corresponding to the six summit eruptions, although juvenile materials were identified only in 4 units (unit 2, 4, 5, 6). We selected about 100 juvenile grains sampled from the bottom to the top of each level, to be analyzed by scanning electron microscopy. The study of juvenile morphological features allowed us to recognize the existence of three characteristic morphotypes, showing marked differences in their external morphologies and internal textures (from poorly to highly crystallized and vesiculated clasts). The distribution of these morphotypes is non-homogeneous along the eruptive sequence indicating changes of dynamics during magma ascent. Juveniles do not show features inherited from the interaction with external water. Vesicle Volume Distributions of the selected ash grains show that the three types of pyroclasts experienced

  17. Multi-decadal satellite measurements of passive and eruptive volcanic SO2 emissions

    Science.gov (United States)

    Carn, Simon; Yang, Kai; Krotkov, Nickolay; Prata, Fred; Telling, Jennifer

    2015-04-01

    strongest volcanic SO2 sources between 2004 and 2015. OMI measurements are most sensitive to SO2 emission rates on the order of ~1000 tons/day or more, and thus the satellite data provide new constraints on the location and persistence of major volcanic SO2 sources. We find that OMI has detected non-eruptive SO2 emissions from at least ~60 volcanoes since 2004. Results of our analysis reveal the emergence of several major tropospheric SO2 sources that are not prominent in existing inventories (Ambrym, Nyiragongo, Turrialba, Ubinas), the persistence of some well-known sources (Etna, Kilauea) and a possible decline in emissions at others (e.g., Lascar). The OMI measurements provide particularly valuable information in regions lacking regular ground-based monitoring such as Indonesia, Melanesia and Kamchatka. We describe how the OMI measurements of SO2 total column, and their probability density function, can be used to infer SO2 emission rates for compatibility with existing emissions data and assimilation into chemical transport models. The satellite-derived SO2 emission rates are in good agreement with ground-based measurements from frequently monitored volcanoes (e.g., from the NOVAC network), but differ for other volcanoes. We conclude that some ground-based SO2 measurements may be biased high if collected during periods of elevated unrest, and hence may not be representative of long-term average emissions.

  18. Fixed drug eruption resulting from fluconazole use: a case report

    Directory of Open Access Journals (Sweden)

    Tavallaee Mahkam

    2009-07-01

    Full Text Available Abstract Introduction Fluconazole is a widely used antifungal agent with a possible side effect of fixed drug eruption. However, this adverse drug effect is absent from the reported list of possible side effects of fluconazole. We are presenting a rare case in our report. Case presentation A 25-year-old Iranian woman developed fixed drug eruptions on different sites of her body after taking five doses of fluconazole to treat vaginal candidiasis. A positive patch test, positive oral challenge test and skin biopsy were all found to be consistent with fixed drug eruption. Conclusion Fluconazole is a widely prescribed drug, used mainly to treat candidiasis. Fixed drug eruption as a possible side effect of Fluconazole is not well known and thus, the lesions may be misdiagnosed and mistreated. Based on our findings, which are consistent with a number of other practitioners, we recommend adding fixed drug eruption to the list of possible side effects of fluconazole.

  19. Spontaneous Eruption of Premolar Associated with a Dentigerous Cyst

    Directory of Open Access Journals (Sweden)

    Irla Karlinne Ferreira de Carvalho

    2016-01-01

    Full Text Available Dentigerous cyst (DC is the second most common odontogenic cyst with greater incidence in young patients. It presents as a unilocular, asymptomatic radiolucency involving the crown of an impacted tooth, commonly noticed in X-rays to investigate absence, wrong tooth position, or delay in the chronology of eruption. Decompression/marsupialization (D/M is the most implemented treatment, especially when preserving the tooth involved is advised. The aim of this study is to discuss the DC characteristics that contribute to spontaneous eruption of premolars, by reporting the case of a conservative treatment of DC. This eruption depends on factors such as age, angulation of inclusion, rate of root formation, depth of inclusion, and eruption space. This paper reports the case of a 10-year-old patient with a radiolucent lesion diagnosed as DC involving element 35, which erupted as a result of treatment. The patient was observed during 1 year and 6 months.

  20. Spontaneous Eruption of Premolar Associated with a Dentigerous Cyst.

    Science.gov (United States)

    de Carvalho, Irla Karlinne Ferreira; Luna, Anibal Henrique Barbosa

    2016-01-01

    Dentigerous cyst (DC) is the second most common odontogenic cyst with greater incidence in young patients. It presents as a unilocular, asymptomatic radiolucency involving the crown of an impacted tooth, commonly noticed in X-rays to investigate absence, wrong tooth position, or delay in the chronology of eruption. Decompression/marsupialization (D/M) is the most implemented treatment, especially when preserving the tooth involved is advised. The aim of this study is to discuss the DC characteristics that contribute to spontaneous eruption of premolars, by reporting the case of a conservative treatment of DC. This eruption depends on factors such as age, angulation of inclusion, rate of root formation, depth of inclusion, and eruption space. This paper reports the case of a 10-year-old patient with a radiolucent lesion diagnosed as DC involving element 35, which erupted as a result of treatment. The patient was observed during 1 year and 6 months.

  1. Drawing the Curtain on Enceladus' South-Polar Eruptions

    Science.gov (United States)

    Spitale, Joseph N.; Hurford, Terry A.; Rhoden, Alyssa R.; Berkson, Emily E.; Platts, Symeon S.

    2015-11-01

    For a comprehensive description of Enceladus' south-polar eruptions observed at high resolution, they must be represented as broad curtains rather than discrete jets. Meanders in the fractures from which the curtains of material erupt give rise to optical illusions that look like discrete jets, even along fractures with no local variations in eruptive activity, implying that many features previously identified as "jets" are in fact phantoms. By comparing Cassini images with model curtain eruptions, we are able to obtain maps of eruptive activity that are not biased by the presence of those phantom jets. The average of our activity maps over all times agrees well with thermal maps produced by Cassini CIRS. We can best explain the observed curtains by assuming spreading angles with altitude of up to 14° and zenith angles of up to 8°, for curtains observed in geometries that are sensitive to those quantities.

  2. Do volcanic eruptions affect climate? Sulfur gases may cause cooling

    Science.gov (United States)

    Self, Stephen; Rampino, Michael R.

    1988-01-01

    The relationship between volcanic eruptions on earth and the observed climatic changes is investigated. The results of the comparison and analyses of volcanologic and climatologic data sets for the years between 1880 and 1980 indicate that changes in temperature caused by even of the largest eruptions recorded during this time were about the same as normal variations in temperature. However, when temperature records for several months or years preceding and following a given eruption were analyzed, a statistically significant temperature decrease of 0.2-0.5 C was found for the periods of one to two years immediately following some of the 19th and 20th century explosive events that prodiced large aerosol clouds (e.g., Krakatau and Agung eruptions). It is suggested that the content of sulfur in the erupted magma determines the size of aerosol cloud producing the cooling effect.

  3. Fitful and protracted magma assembly leading to a giant eruption, Youngest Toba Tuff, Indonesia

    Science.gov (United States)

    Reid, Mary R; Vazquez, Jorge A.

    2017-01-01

    The paroxysmal eruption of the 74 ka Youngest Toba Tuff (YTT) of northern Sumatra produced an extraordinary 2800 km3 of non-welded to densely welded ignimbrite and co-ignimbrite ash-fall. We report insights into the duration of YTT magma assembly obtained from ion microprobe U-Th and U-Pb dates, including continuous age spectra over >50% of final zircon growth, for pumices and a welded tuff spanning the compositional range of the YTT. A relatively large subpopulation of zircon crystals nucleated before the penultimate caldera-related eruption at 501 ka, but most zircons yielded interior dates 100-300 ka thereafter. Zircon nucleation and growth was likely episodic and from diverse conditions over protracted time intervals of >100 to >500 ka. Final zircon growth is evident as thin rim plateaus that are in Th/U chemical equilibrium with hosts, and that give crystallization ages within tens of ka of eruption. The longevity and chemical characteristics of the YTT zircons, as well as evidence for intermittent zircon isolation and remobilization associated with magma recharge, is especially favored at the cool and wet eutectoid conditions that characterize at least half of the YTT, wherein heat fluxes could dissolve major phases but have only a minor effect on larger zircon crystals. Repeated magma recharge may have contributed to the development of compositional zoning in the YTT but, considered together with limited allanite, quartz, and other mineral dating and geospeedometry, regular perturbations to the magma reservoir over >400 ka did not lead to eruption until 74 ka ago.

  4. Darwin's triggering mechanism of volcano eruptions

    Science.gov (United States)

    Galiev, Shamil

    2010-05-01

    Charles Darwin wrote that ‘… the elevation of many hundred square miles of territory near Concepcion is part of the same phenomenon, with that splashing up, if I may so call it, of volcanic matter through the orifices in the Cordillera at the moment of the shock;…' and ‘…a power, I may remark, which acts in paroxysmal upheavals like that of Concepcion, and in great volcanic eruptions,…'. Darwin reports that ‘…several of the great chimneys in the Cordillera of central Chile commenced a fresh period of activity ….' In particular, Darwin reported on four-simultaneous large eruptions from the following volcanoes: Robinson Crusoe, Minchinmavida, Cerro Yanteles and Peteroa (we cite the Darwin's sentences following his The Voyage of the Beagle and researchspace. auckland. ac. nz/handle/2292/4474). Let us consider these eruptions taking into account the volcano shape and the conduit. Three of the volcanoes (Minchinmavida (2404 m), Cerro Yanteles (2050 m), and Peteroa (3603 m)) are stratovolcanos and are formed of symmetrical cones with steep sides. Robinson Crusoe (922 m) is a shield volcano and is formed of a cone with gently sloping sides. They are not very active. We may surmise, that their vents had a sealing plug (vent fill) in 1835. All these volcanoes are conical. These common features are important for Darwin's triggering model, which is discussed below. The vent fill material, usually, has high level of porosity and a very low tensile strength and can easily be fragmented by tension waves. The action of a severe earthquake on the volcano base may be compared with a nuclear blast explosion of the base. It is known, that after a underground nuclear explosion the vertical motion and the surface fractures in a tope of mountains were observed. The same is related to the propagation of waves in conical elements. After the explosive load of the base. the tip may break and fly off at high velocity. Analogous phenomenon may be generated as a result of a

  5. Remote Sensing and GIS as Tools for Identifying Risk for Phreatomagmatic Eruptions in the Bishoftu Volcanic Field, Ethiopia

    Science.gov (United States)

    Pennington, H. G.; Graettinger, A.

    2017-12-01

    Bishoftu is a fast-growing town in the Oromia region of Ethiopia, located 47 km southeast of the nation's capital, Addis Ababa. It is situated atop a monogenetic basaltic volcanic field, called the Bishoftu Volcanic Field (BVF), which is composed of maar craters, scoria cones, lava flows, and rhyolite domes. Although not well dated, the morphology and archeological evidence have been used to infer a Holocene age, indicating that the community is exposed to continued volcanic risk. The presence of phreatomagmatic constructs in particular indicates that the hazards are not only vent-localized, but may have far reaching impacts. Hazard mapping is an essential tool for evaluating and communicating risks. This study presents the results of GIS analyses of proximal and distal syn-eruptive hazards associated with phreatomagmatic eruptions in the BVF. A digitized infrastructure map based on a SPOT 6 satellite image is used to identify the areas at risk from eruption scenarios. Parameters such as wind direction, vent location, and explosion energy are varied for hazard simulations to quantify the area impacted by different eruption scenarios. Proximal syn-eruptive hazards include tephra fall, base pyroclastic surges, and ballistic bombs. Distal hazards include predominantly ash fall. Eruption scenarios are simulated using Eject and Plumeria models as well as similar case studies from other urban volcanic fields. Within 5 km of the volcanic field center, more than 30 km2 of residential and commercial/industrial infrastructure will be damaged by proximal syn-eruptive hazards, in addition to 34 km2 of agricultural land, 291 km of roads, more than 10 km of railway, an airport, and two health centers. Within 100 km of the volcanic field center, ash fall will affect 3946 km2 of agricultural land, 179 km2 of residential land, and 28 km2 of commercial/industrial land. Approximately 2700 km of roads and railways, 553 km of waterways, an airport, and 14 health centers are located

  6. Reconstruction of the eruptive activity on the NE sector of Stromboli volcano: timing of flank eruptions since 15 ka

    NARCIS (Netherlands)

    Calvari, S.; Branca, S.; Corsaro, R.A.; De Beni, E.; Miraglia, L.; Norini, G.; Wijbrans, J.R.; Boschi, E.

    2011-01-01

    A multidisciplinary geological and compositional investigation allowed us to reconstruct the occurrence of flank eruptions on the lower NE flank of Stromboli volcano since 15 ka. The oldest flank eruption recognised is Roisa, which occurred at ~15 ka during the Vancori period, and has transitional

  7. Estimating rates of decompression from textures of erupted ash particles produced by 1999-2006 eruptions of Tungurahua volcano, Ecuador

    Science.gov (United States)

    Wright, Heather M.N.; Cashman, Katharine V.; Mothes, Patricia A.; Hall, Minard L.; Ruiz, Andrés Gorki; Le Pennec, Jean-Luc

    2012-01-01

    Persistent low- to moderate-level eruptive activity of andesitic volcanoes is difficult to monitor because small changes in magma supply rates may cause abrupt transitions in eruptive style. As direct measurement of magma supply is not possible, robust techniques for indirect measurements must be developed. Here we demonstrate that crystal textures of ash particles from 1999 to 2006 Vulcanian and Strombolian eruptions of Tungurahua volcano, Ecuador, provide quantitative information about the dynamics of magma ascent and eruption that is difficult to obtain from other monitoring approaches. We show that the crystallinity of erupted ash particles is controlled by the magma supply rate (MSR); ash erupted during periods of high magma supply is substantially less crystalline than during periods of low magma supply. This correlation is most easily explained by efficient degassing at very low pressures (<<50 MPa) and degassing-driven crystallization controlled by the time available prior to eruption. Our data also suggest that the observed transition from intermittent Vulcanian explosions at low MSR to more continuous periods of Strombolian eruptions and lava fountains at high MSR can be explained by the rise of bubbles through (Strombolian) or trapping of bubbles beneath (Vulcanian) vent-capping, variably viscous (and crystalline) magma.

  8. Geochemical surveys in the Lusi mud eruption

    Science.gov (United States)

    Sciarra, Alessandra; Mazzini, Adriano; Etiope, Giuseppe; Inguaggiato, Salvatore; Hussein, Alwi; Hadi J., Soffian

    2016-04-01

    The Lusi mud eruption started in May 2006 following to a 6.3 M earthquake striking the Java Island. In the framework of the Lusi Lab project (ERC grant n° 308126) we carried out geochemical surveys in the Sidoarjo district (Eastern Java Island, Indonesia) to investigate the gas bearing properties of the Watukosek fault system that crosses the Lusi mud eruption area. Soil gas (222Rn, CO2, CH4) concentration and flux measurements were performed 1) along two detailed profiles (~ 1km long), trending almost W-E direction, and 2) inside the Lusi embankment (about 7 km2) built to contain the erupted mud. Higher gas concentrations and fluxes were detected at the intersection with the Watukosek fault and the antithetic fault system. These zones characterized by the association of higher soil gas values constitute preferential migration pathways for fluids towards surface. The fractures release mainly CO2 (with peaks up to 400 g/m2day) and display higher temperatures (up to 41°C). The main shear zones are populated by numerous seeps that expel mostly CH4. Flux measurements in the seeping pools reveal that φCO2 is an order of magnitude higher than that measured in the fractures, and two orders of magnitude higher for φCH4. An additional geochemical profile was completed perpendicularly to the Watukosek fault escarpement (W-E direction) at the foots of the Penanngungang volcano. Results reveal CO2 and CH4 flux values significantly lower than those measured in the embankment, however an increase of radon and flux measurements is observed approaching the foots of the escarpment. These measurements are complemented with a database of ~350 CH4 and CO2 flux measurements and some soil gas concentrations (He, H2, CO2, CH4 and C2H6) and their isotopic analyses (δ13C-CH4, δD-CH4 and δ13C-CO2). Results show that the whole area is characterized by diffused gas release through seeps, fractures, microfractures and soil degassing. The collected results shed light on the origin of the

  9. TORNADO-LIKE EVOLUTION OF A KINK-UNSTABLE SOLAR PROMINENCE

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wensi; Liu, Rui; Wang, Yuming, E-mail: rliu@ustc.edu.cn [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China)

    2017-01-01

    We report on the tornado-like evolution of a quiescent prominence on 2014 November 1. The eastern section of the prominence first rose slowly, transforming into an arch-shaped structure as high as ∼150 Mm above the limb; the arch then writhed moderately in a left-handed sense, while the original dark prominence material emitted in the Fe ix 171 Å passband, and a braided structure appeared at the eastern edge of the warped arch. The unraveling of the braided structure was associated with a transient brightening in the EUV and apparently contributed to the formation of a curtain-like structure (CLS). The CLS consisted of myriad thread-like loops rotating counterclockwise about the vertical if viewed from above. Heated prominence material was observed to slide along these loops and land outside the filament channel. The tornado eventually disintegrated and the remaining material flew along a left-handed helical path constituting approximately a full turn, as corroborated through stereoscopic reconstruction, into the cavity of the stable, western section of the prominence. We suggest that the tornado-like evolution of the prominence was governed by the helical kink instability, and that the CLS formed through magnetic reconnections between the prominence field and the overlying coronal field.

  10. Prominence-corona interface compared with the chromosphere-corona transition region

    Energy Technology Data Exchange (ETDEWEB)

    Orrall, F Q; Schmahl, E J [Harvard Coll. Observatory, Cambridge, Mass. (USA)

    1976-11-01

    The intensities of 52 EUV emission lines from each of 9 hedgerow prominences observed at the limb with the Harvard experiment on ATM-Skylab have been compared with intensities from the interior of network cells at the center of the disk, in order to compare the prominence-corona (P-C) interface with the chromosphere-corona (C-C) transition region. The intensity ratio Isub(cell)/Isub(prominence) for each line varies systematically (in all of the prominences observed), with the temperature of formation of the line as approximately Tsup(-0.6). The density sensitive C III (formed at T approximately 9x10/sup 4/ K) line ratio Isub(lambda1175)/Isub(lambda977) implies an average density 1.3x10/sup 9/ electrons cm/sup -3/ in the P-C interface and approximately 4 times this value in the C-C transition of the cells. The total optical thickness at the head of the Lyman continuum is < approximately 10 in most of the prominences studied; in two of the prominences, however, the possibility that tau/sub 0/ is large cannot be rejected. Methods of analysis of these EUV data are developed assuming both a resolved and an unresolved internal prominence structure. Although the systematic differences between the P-C interface and the C-C transition are stressed, the similarities are probably more remarkable and may be a result of fine structure in the C-C transition.

  11. What factors control the size of an eruption?

    Science.gov (United States)

    Gudmundsson, Agust

    2017-04-01

    For human society, eruption sizes (eruptive volumes or masses) are of the greatest concern. In particular, the largest eruptions, producing volumes of the order of hundreds or thousands of cubic kilometres, provide, together with meteoritic impacts, the greatest natural threats to mankind. Eruptive volumes tend to follow power laws so that most eruptions are comparatively small whereas a few are very large. It follows that a while during most ruptures of the source chambers a small fraction of the magma leaves the chamber, in some ruptures a very large fraction of the magma leaves the chamber. Most explosive eruptions larger than about 25 km3 are associated with caldera collapse. In the standard 'underpressure' ('lack of magmatic support') model, however, the collapse is the consequence, not the cause, of the large eruption. For poroelastic models, typically less than 4% of the magma in a felsic chamber and less than 0.1% of the magma in a mafic chamber leaves the chamber during rupture (and eventual eruption). In some caldera models, however, 20-70% of the magma is supposed to leave the chamber before the ring-fault forms and the caldera block begins to subside. In these models any amount of magma can flow out of the chamber following its rupture and there is apparently no way to forecast either the volume of magma injected from the chamber (hence the potential size of an eventual eruption) or the conditions for caldera collapse. An alternative model is proposed here. In this model normal (small) eruptions are controlled by standard poroelastity behaviour of the chamber, whereas large eruptions are controlled by chamber-volume reduction or shrinkage primarily through caldera/graben block subsidence into the chamber. Volcanotectonic stresses are then a major cause of ring-fault/graben boundary-fault formation. When large slips occur on these faults, the subsiding crustal block reduces the volume of the underlying chamber/reservoir, thereby maintaining its excess

  12. Eruption and emplacement timescales of ignimbrite super-eruptions from thermo-kinetics of glass shards

    Directory of Open Access Journals (Sweden)

    Yan eLavallée

    2015-02-01

    Full Text Available Super-eruptions generating hundreds of cubic kilometres of pyroclastic density currents are commonly recorded by thick, welded and lava-like ignimbrites. Despite the huge environmental impact inferred for this type of eruption, little is yet known about the timescales of deposition and post-depositional flow. Without these timescales, the critical question of the duration of any environmental impact, and the ensuing gravity of its effects for the Earth system, eludes us. The eruption and welding of ignimbrites requires three transects of the glass transition. Magma needs to: 1 fragment during ascent, 2 liquefy and relax during deposition, agglutination and welding (sintering, and 3 quench by cooling into the glassy state. Here we show that welding is a rapid, syn-depositional process and that the welded ignimbrite sheet may flow for up to a few hours before passing through the glass transition a final time. Geospeedometry reveals that the basal vitrophyre of the Grey’s Landing ignimbrite underwent the glass transition at a rate of ~0.1 °C.min^-1 at 870 °C; that is, 30-180 °C below pre-eruptive geothermometric estimates. Application of a 1-D cooling model constrains the timescale of deposition, agglutination, and welding of the basal vitrophyre to less than 1 hour, and possibly even tens of minutes. Thermo-mechanical iteration of the sintering process indicates an optimal temperature solution for the emplacement of the vitrophyres at 966 °C. The vitrophyres reveal a Newtonian rheology up to 46 MPa, which suggests that the ash particles annealed entirely during welding and that viscous energy dissipation is unlikely from loading conditions alone, unless shear stresses imposed by the overlying ash flow were excessively high and sustained over long distances. The findings underline the value of the term 'lava-like' flow to describe the end rheology of Snake River-type ignimbrites, fully consistent with the typical lithofacies observed.

  13. The Tala Tuff, La Primavera caldera Mexico. Pre-eruptive conditions and magma processes before eruption

    Science.gov (United States)

    Sosa-Ceballos, G.

    2015-12-01

    La Primavera caldera, Jalisco Mexico, is a Pleistocenic volcanic structure formed by dome complexes and multiple pyroclastic flows and fall deposits. It is located at the intersection of the Chapala, Colima, and Tepic grabens in western Mexico. The first volcanic activity associated to La Primavera started ~0.1 Ma with the emission of pre-caldera lavas. The caldera collapse occurred 95 ka and is associated to the eruption of ~20 km3of pumice flows known as the Tala tuff (Mahood 1980). The border of the caldera was replaced by a series of domes dated in 75-30 ky, which partially filled the inner depression of the caldera with pyroclastic flows and falls. For more than a decade the Federal Commission of Electricity in Mexico (CFE) has prospected and evaluated the geothermal potential of the Cerritos Colorados project at La Primavera caldera. In order to better understand the plumbing system that tapped the Tala tuff and to investigate its relation with the potential geothermal field at La Primavera we performed a series of hydrothermal experiments and studied melt inclusions hosted in quartz phenocrysts by Fourier Infra red stectroscopy (FTIR). Although some post caldera products at La Primavera contain fayalite and quartz (suggesting QFM conditions) the Tala tuff does not contain fayalite and we ran experiments under NNO conditions. The absence of titanomagnetite does not allowed us to calculate pre-eruptive temperature. However, the stability of quartz and plagioclase, which are natural phases, suggest that temperature should be less than 750 °C at a pressure of 200 MPa. The analyses of H2O and CO2 dissolved in melt inclusions yielded concentrations of 2-5 wt.% and 50-100 ppm respectively. This data confirm that the pre-eruptive pressure of the Tala tuff is ~200 MPa and in addition to major elements compositions suggest that the Tala tuff is either, compositionally zoned or mixed with other magma just prior to eruption.

  14. POLYMORPHOUS LIGHT ERUPTION – A REVIEW

    Directory of Open Access Journals (Sweden)

    Yogeesh Hosahalli Rajaiah

    2013-07-01

    Full Text Available Polymprhouos light eruption is the most common idiopathic photodermatosis. It is a sun induced cutaneous reaction characterized by onset itchy erathematous papules, plaques, vesicles or erythema multiforme type of lesions after brief exposure to sunlight. Sun-exposed areas of the body or rarely the partially covered areas are commonly involved. PLE is more common in temperate climates than in tropics. It begins usually at the onset of summer and moderates as the summer progresses. In most patients it usually runs a benign course. Diagnosis is mainly on clinical grounds. Therapy involves avoidance of sun-exposure and use of sunscreens. Cases not responding to simple measures require PUVA (Psoralen and Ultraviolet A or UVB (ultraviolet B therapy. Other alternative suggested therapies with variable success include oral hydroxychloroquine, beta-carotene, thalidomide and nicotinamide.

  15. Ursodeoxycholic acid induced generalized fixed drug eruption.

    Science.gov (United States)

    Ozkol, Hatice Uce; Calka, Omer; Dulger, Ahmet Cumhur; Bulut, Gulay

    2014-09-01

    Fixed drug eruption (FDE) is a rare form of drug allergies that recur at the same cutaneous or mucosal site in every usage of drug. Single or multiple round, sharply demarcated and dusky red plaques appear soon after drug exposure. Ursodeoxycholic acid (UDCA: 3α,7β-dihydroxy-5β-cholanic acid) is used for the treatment of cholestatic liver diseases. Some side effects may be observed, such as diarrhea, dyspepsia, pruritus and headaches. We encountered only three cases of lichenoid reaction regarding the use of UDCA among previous studies. In this article, we reported a generalized FDE case related to UDCA intake in a 59-year-old male patient with cholestasis for the first time in the literature.

  16. Introduction to the 2012-2013 Tolbachik eruption special issue

    Science.gov (United States)

    Edwards, Benjamin R.; Belousov, Alexander; Belousova, Marina; Volynets, Anna

    2015-12-01

    The Tolbachik volcanic complex in central Kamchatka holds a special place in global volcanological studies. It is one of 4 areas of extensive historic volcanic activity in the northern part of the Central Kamchatka Depression (the others being Klyuchevskoy, Bezymianny, Shiveluch), and is part of the Klyuchevskoy volcanic group, which is one of the most active areas of volcanism on Earth. Tolbachik is especially well-known due largely to the massive 1975-1976 eruption that became known as the Great Tolbachik Fissure eruption (GTFE; Fedotov, 1983; Fedotov et al., 1984). This was one of the first eruptions in Russia to be predicted based on precursory seismic activity, based on M5 earthquakes approximately one week before the eruption started, and was intensively studied during its course by a large number of Russian scientists. A summary of those studies was published, first in Russian and then in English, and it became widely read for many reasons. One in particular is that the eruption was somewhat unusual for a subduction zone setting; although many subduction zone stratovolcanoes have associated basaltic tephra cone-lava fields, this was the first such Hawaiian-style eruption to be widely observed. After the end of the eruption in 1976, the complex showed no signs of activity until 27 November 2012, when increased seismic activity was registered by the Kamchatka Branch of the Russian Geophysical Survey and a red glow from the eruption site was first noticed through the snowstorm haze. This prompted them, and then the Kamchatka Volcanic Emergency Response Team (KVERT) to issue an alert that activity was coming from the south flank of Plosky Tolbachik volcano, the younger of two volcanic edifices (the older is Ostry Tolbachik) that together make up the bulk of the complex along with tephra cone-lava fields that lie along a NE-SW fissure zone that transects Plosky Tolbachik. The new eruption lasted for more than 250 days and, like the 1975-1976 eruption, was

  17. Motions in Prominence Barbs as observed by Hinode/SOT and IRIS

    Science.gov (United States)

    Kucera, Therese A.; Ofman, Leon; Tarbell, Theodore D.

    2016-05-01

    We discuss observations of prominence barb dynamics as observed by Hinode/SOT and IRIS. Prominence barbs extend outwards to the side of the main prominence spine and downwards towards the chromosphere. Their properties, including the structure of their magnetic field and the nature of the motions observed in them are a subject of current debate. We use a combination of high cadence, high resolution imaging, H-alpha Doppler, and Mg II line profile data to analyze and understand waves and flows in barbs and discuss their ramifications in terms of a model of the barb magnetic field as collection of dipped field lines.

  18. Magmatic densities control erupted volumes in Icelandic volcanic systems

    Science.gov (United States)

    Hartley, Margaret; Maclennan, John

    2018-04-01

    Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ). By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallisation under Iceland.

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

    Science.gov (United States)

    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.

  20. The association between childhood obesity and tooth eruption.

    Science.gov (United States)

    Must, Aviva; Phillips, Sarah M; Tybor, David J; Lividini, Keith; Hayes, Catherine

    2012-10-01

    Obesity is a growth-promoting process as evidenced by its effect on the timing of puberty. Although studies are limited, obesity has been shown to affect the timing of tooth eruption. Both the timing and sequence of tooth eruption are important to overall oral health. The purpose of this study was to examine the association between obesity and tooth eruption. Data were combined from three consecutive cycles (2001-2006) of the National Health and Nutrition Examination Survey (NHANES) and analyzed to examine associations between the number of teeth erupted (NET) and obesity status (BMI z-score >95th percentile BMI relative to the Centers for Disease Control and Prevention (CDC) growth reference) among children 5 up to 14 years of age, controlling for potential confounding by age, gender, race, and socioeconomic status (SES). Obesity is significantly associated with having a higher average NET during the mixed dentition period. On average, teeth of obese children erupted earlier than nonobese children with obese children having on average 1.44 more teeth erupted than nonobese children, after adjusting for age, gender, and race/ethnicity (P erupted than nonobese children after adjusting for gender, age, and race. These findings may have clinical importance in the area of dental and orthodontic medicine both in terms of risk for dental caries due to extended length of time exposed in the oral cavity and sequencing which may increase the likelihood of malocclusions.

  1. Solar filament material oscillations and drainage before eruption

    International Nuclear Information System (INIS)

    Bi, Yi; Jiang, Yunchun; Yang, Jiayan; Hong, Junchao; Li, Haidong; Yang, Dan; Yang, Bo

    2014-01-01

    Both large-amplitude longitudinal (LAL) oscillations and material drainage in a solar filament are associated with the flow of material along the filament axis, often followed by an eruption. However, the relationship between these two motions and a subsequent eruption event is poorly understood. We analyze a filament eruption using EUV imaging data captured by the Atmospheric Imaging Array on board the Solar Dynamics Observatory and the Hα images from the Global Oscillation Network Group. Hours before the eruption, the filament was activated, with one of its legs undergoing a slow rising motion. The asymmetric activation inclined the filament relative to the solar surface. After the active phase, LAL oscillations were observed in the inclined filament. The oscillation period increased slightly over time, which may suggest that the magnetic fields supporting the filament evolve to be flatter during the slow rising phase. After the oscillations, a significant amount of filament material was drained toward one filament endpoint, followed immediately by the violent eruption of the filament. The material drainage may further support the change in magnetic topology prior to the eruption. Moreover, we suggest that the filament material drainage could play a role in the transition from a slow to a fast rise of the erupting filament.

  2. Magmatic Densities Control Erupted Volumes in Icelandic Volcanic Systems

    Directory of Open Access Journals (Sweden)

    Margaret Hartley

    2018-04-01

    Full Text Available Magmatic density and viscosity exert fundamental controls on the eruptibility of magmas. In this study, we investigate the extent to which magmatic physical properties control the eruptibility of magmas from Iceland's Northern Volcanic Zone (NVZ. By studying subaerial flows of known age and volume, we are able to directly relate erupted volumes to magmatic physical properties, a task that has been near-impossible when dealing with submarine samples dredged from mid-ocean ridges. We find a strong correlation between magmatic density and observed erupted volumes on the NVZ. Over 85% of the total volume of erupted material lies close to a density and viscosity minimum that corresponds to the composition of basalts at the arrival of plagioclase on the liquidus. These magmas are buoyant with respect to the Icelandic upper crust. However, a number of small-volume eruptions with densities greater than typical Icelandic upper crust are also found in Iceland's neovolcanic zones. We use a simple numerical model to demonstrate that the eruption of magmas with higher densities and viscosities is facilitated by the generation of overpressure in magma chambers in the lower crust and uppermost mantle. This conclusion is in agreement with petrological constraints on the depths of crystallization under Iceland.

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

    Science.gov (United States)

    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.

  4. Episodic Holocene eruption of the Salton Buttes rhyolites, California, from paleomagnetic, U-Th, and Ar/Ar dating

    Science.gov (United States)

    Wright, Heather M.; Vazquez, Jorge A.; Champion, Duane E.; Calvert, Andrew T.; Mangan, Margaret T.; Stelten, Mark E.; Cooper, Kari M.; Herzig, Charles; Schriener Jr., Alexander

    2015-01-01

    In the Salton Trough, CA, five rhyolite domes form the Salton Buttes: Mullet Island, Obsidian Butte, Rock Hill, North and South Red Hill, from oldest to youngest. Results presented here include 40Ar/39Ar anorthoclase ages, 238U-230Th zircon crystallization ages, and comparison of remanent paleomagnetic directions with the secular variation curve, which indicate that all domes are Holocene. 238U-230Th zircon crystallization ages are more precise than but within uncertainty of 40Ar/39Ar anorthoclase ages, suggesting that zircon crystallization proceeded until shortly before eruption in all cases except one. Remanent paleomagnetic directions require three eruption periods: (1) Mullet Island, (2) Obsidian Butte, and (3) Rock Hill, North Red Hill, and South Red Hill. Borehole cuttings logs document up to two shallow tephra layers. North and South Red Hills likely erupted within 100 years of each other, with a combined 238U-230Th zircon isochron age of: 2.83 ± 0.60 ka (2 sigma); paleomagnetic evidence suggests this age predates eruption by hundreds of years (1800 cal BP). Rock Hill erupted closely in time to these eruptions. The Obsidian Butte 238U-230Th isochron age (2.86 ± 0.96 ka) is nearly identical to the combined Red Hill age, but its Virtual Geomagnetic Pole position suggests a slightly older age. The age of aphyric Mullet Island dome is the least well constrained: zircon crystals are resorbed and the paleomagnetic direction is most distinct; possible Mullet Island ages include ca. 2300, 5900, 6900, and 7700 cal BP. Our results constrain the duration of Salton Buttes volcanism to between ca. 5900 and 500 years.

  5. The 808 nm Laser-Assisted Surgery as an Adjunct to Orthodontic Treatment of Delayed Tooth Eruption.

    Science.gov (United States)

    Seifi, Massoud; Vahid-Dastjerdi, Elahe; Ameli, Nazila; Badiee, Mohammad-Reza; Younessian, Farnaz; Amdjadi, Parisa

    2013-01-01

    Failure of teeth to erupt from gingival tissues at usual developmental time is called delayed tooth eruption (DTE). Delayed tooth eruption lead to prolonged fixed orthodontic treatment and its eventual complications. The purpose of the present study was to evaluate the effect of laser-assisted (808 nm) surgical uncovering, on the tooth emergence and orthodontic treatment of DTE. A total of 16 orthodontic patients were included in this study and were equally assigned to an experimental and a control group. Subjects for experiment consisted of eight patients (6 girls and 2 boys) with a mean age of 14±0.9 years. All patients exhibited delayed second premolar eruption. The laser wavelength was 810 nm and it was set in a continuous wave mode at a power output of 1.6 watt with a 0.3-mm diameter fiber tip. When the target tissue was sufficiently anesthetized, the tip was directed at an angle of 10 to 20 degrees to the tissue (light contact mode); and was applied continuously for approximately 12 Seconds until an acceptable tooth exposure area was visible. The facial axis of the clinical crown (FACC) line represents the most prominent portion of the facial central lobe for premolars. All orthodontic brackets are aligned along this reference and are located on FA (Facial Axis) point. The standard for adequate tooth eruption was the accessibility of facial axis of the clinical crown (FACC) for bonding the brackets. Data gathered from the patients were statistically surveyed and compared by means of Tukey's Test and Analysis of Variance (ANOVA). All patients showed good gingival status, no significant bleeding during or immediately after the surgery, and acceptable level of healing after laser surgery. The biologic width of the teeth was preserved and no violation of this important periodontal parameter was observed. The average time for accessing the FA point in experimental group was 11±1.1 weeks and the mentioned period was increased to 25±1.8 weeks in control group

  6. MULTI-LINE STOKES INVERSION FOR PROMINENCE MAGNETIC-FIELD DIAGNOSTICS

    International Nuclear Information System (INIS)

    Casini, R.; Lopez Ariste, A.; Paletou, F.; Leger, L.

    2009-01-01

    We present test results on the simultaneous inversion of the Stokes profiles of the He I lines at 587.6 nm (D 3 ) and 1083.0 nm in prominences (90 deg. scattering). We created data sets of synthetic Stokes profiles for the case of quiescent prominences (B -3 of the peak intensity for the polarimetric sensitivity of the simulated observations. In this work, we focus on the error analysis for the inference of the magnetic field vector, under the usual assumption that the prominence can be assimilated to a slab of finite optical thickness with uniform magnetic and thermodynamic properties. We find that the simultaneous inversion of the two lines significantly reduces the errors on the inference of the magnetic field vector, with respect to the case of single-line inversion. These results provide a solid justification for current and future instrumental efforts with multi-line capabilities for the observations of solar prominences and filaments.

  7. QUIESCENT PROMINENCE DYNAMICS OBSERVED WITH THE HINODE SOLAR OPTICAL TELESCOPE. I. TURBULENT UPFLOW PLUMES

    International Nuclear Information System (INIS)

    Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

    2010-01-01

    Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) 'arches' or 'bubbles' that 'inflate' from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex 'roll-up' of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) 'optical flow' code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s -1 , which is supersonic for a ∼10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s -1 . Typical lifetimes range from 300 to 1000 s (∼5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km 2 s -1 reaching maximum projected areas from 2 to 15 Mm 2 . Maximum contrast of the dark flows relative to the bright prominence plasma in

  8. Quiescent Prominence Dynamics Observed with the Hinode Solar Optical Telescope. I. Turbulent Upflow Plumes

    Science.gov (United States)

    Berger, Thomas E.; Slater, Gregory; Hurlburt, Neal; Shine, Richard; Tarbell, Theodore; Title, Alan; Lites, Bruce W.; Okamoto, Takenori J.; Ichimoto, Kiyoshi; Katsukawa, Yukio; Magara, Tetsuya; Suematsu, Yoshinori; Shimizu, Toshifumi

    2010-06-01

    Hinode/Solar Optical Telescope (SOT) observations reveal two new dynamic modes in quiescent solar prominences: large-scale (20-50 Mm) "arches" or "bubbles" that "inflate" from below into prominences, and smaller-scale (2-6 Mm) dark turbulent upflows. These novel dynamics are related in that they are always dark in visible-light spectral bands, they rise through the bright prominence emission with approximately constant speeds, and the small-scale upflows are sometimes observed to emanate from the top of the larger bubbles. Here we present detailed kinematic measurements of the small-scale turbulent upflows seen in several prominences in the SOT database. The dark upflows typically initiate vertically from 5 to 10 Mm wide dark cavities between the bottom of the prominence and the top of the chromospheric spicule layer. Small perturbations on the order of 1 Mm or less in size grow on the upper boundaries of cavities to generate plumes up to 4-6 Mm across at their largest widths. All plumes develop highly turbulent profiles, including occasional Kelvin-Helmholtz vortex "roll-up" of the leading edge. The flows typically rise 10-15 Mm before decelerating to equilibrium. We measure the flowfield characteristics with a manual tracing method and with the Nonlinear Affine Velocity Estimator (NAVE) "optical flow" code to derive velocity, acceleration, lifetime, and height data for several representative plumes. Maximum initial speeds are in the range of 20-30 km s-1, which is supersonic for a ~10,000 K plasma. The plumes decelerate in the final few Mm of their trajectories resulting in mean ascent speeds of 13-17 km s-1. Typical lifetimes range from 300 to 1000 s (~5-15 minutes). The area growth rate of the plumes (observed as two-dimensional objects in the plane of the sky) is initially linear and ranges from 20,000 to 30,000 km2 s-1 reaching maximum projected areas from 2 to 15 Mm2. Maximum contrast of the dark flows relative to the bright prominence plasma in SOT images

  9. Historic hydrovolcanism at Deception Island (Antarctica): implications for eruption hazards

    Science.gov (United States)

    Pedrazzi, Dario; Németh, Károly; Geyer, Adelina; Álvarez-Valero, Antonio M.; Aguirre-Díaz, Gerardo; Bartolini, Stefania

    2018-01-01

    Deception Island (Antarctica) is the southernmost island of the South Shetland Archipelago in the South Atlantic. Volcanic activity since the eighteenth century, along with the latest volcanic unrest episodes in the twentieth and twenty-first centuries, demonstrates that the volcanic system is still active and that future eruptions are likely. Despite its remote location, the South Shetland Islands are an important touristic destination during the austral summer. In addition, they host several research stations and three summer field camps. Deception Island is characterised by a Quaternary caldera system with a post-caldera succession and is considered to be part of an active, dispersed (monogenetic), volcanic field. Historical post-caldera volcanism on Deception Island involves monogenetic small-volume (VEI 2-3) eruptions such forming cones and various types of hydrovolcanic edifices. The scientific stations on the island were destroyed, or severely damaged, during the eruptions in 1967, 1969, and 1970 mainly due to explosive activity triggered by the interaction of rising (or erupting) magma with surface water, shallow groundwater, and ice. We conducted a detailed revision (field petrology and geochemistry) of the historical hydrovolcanic post-caldera eruptions of Deception Island with the aim to understand the dynamics of magma-water interaction, as well as characterise the most likely eruptive scenarios from future eruptions. We specifically focused on the Crimson Hill (estimated age between 1825 and 1829), and Kroner Lake (estimated age between 1829 and 1912) eruptions and 1967, 1969, and 1970 events by describing the eruption mechanisms related to the island's hydrovolcanic activity. Data suggest that the main hazards posed by volcanism on the island are due to fallout, ballistic blocks and bombs, and subordinate, dilute PDCs. In addition, Deception Island can be divided into five areas of expected activity due to magma-water interaction, providing additional

  10. [Effects of volcanic eruptions on human health in Iceland. Review].

    Science.gov (United States)

    Gudmundsson, Gunnar; Larsen, Guðrun

    2016-01-01

    Volcanic eruptions are common in Iceland and have caused health problems ever since the settlement of Iceland. Here we describe volcanic activity and the effects of volcanic gases and ash on human health in Iceland. Volcanic gases expelled during eruptions can be highly toxic for humans if their concentrations are high, irritating the mucus membranes of the eyes and upper respiratory tract at lower concentrations. They can also be very irritating to the skin. Volcanic ash is also irritating for the mucus membranes of the eyes and upper respiratory tract. The smalles particles of volcanic ash can reach the alveoli of the lungs. Described are four examples of volcanic eruptions that have affected the health of Icelanders. The eruption of Laki volcanic fissure in 1783-1784 is the volcanic eruption that has caused the highest mortality and had the greatest effects on the well-being of Icelanders. Despite multiple volcanic eruptions during the last decades in Iceland mortality has been low and effects on human health have been limited, although studies on longterm effects are lacking. Studies on the effects of the Eyjafjallajökul eruption in 2010 on human health showed increased physical and mental symptoms, especially in those having respiratory disorders. The Directorate of Health in Iceland and other services have responded promptly to recurrent volcanic eruptions over the last few years and given detailed instructions on how to minimize the effects on the public health. Key words: volcanic eruptions, Iceland, volcanic ash, volcanic gases, health effects, mortality. Correspondence: Gunnar Guðmundsson, ggudmund@landspitali.is.

  11. The Eruption Forecasting Information System (EFIS) database project

    Science.gov (United States)

    Ogburn, Sarah; Harpel, Chris; Pesicek, Jeremy; Wellik, Jay; Pallister, John; Wright, Heather

    2016-04-01

    The Eruption Forecasting Information System (EFIS) project is a new initiative of the U.S. Geological Survey-USAID Volcano Disaster Assistance Program (VDAP) with the goal of enhancing VDAP's ability to forecast the outcome of volcanic unrest. The EFIS project seeks to: (1) Move away from relying on the collective memory to probability estimation using databases (2) Create databases useful for pattern recognition and for answering common VDAP questions; e.g. how commonly does unrest lead to eruption? how commonly do phreatic eruptions portend magmatic eruptions and what is the range of antecedence times? (3) Create generic probabilistic event trees using global data for different volcano 'types' (4) Create background, volcano-specific, probabilistic event trees for frequently active or particularly hazardous volcanoes in advance of a crisis (5) Quantify and communicate uncertainty in probabilities A major component of the project is the global EFIS relational database, which contains multiple modules designed to aid in the construction of probabilistic event trees and to answer common questions that arise during volcanic crises. The primary module contains chronologies of volcanic unrest, including the timing of phreatic eruptions, column heights, eruptive products, etc. and will be initially populated using chronicles of eruptive activity from Alaskan volcanic eruptions in the GeoDIVA database (Cameron et al. 2013). This database module allows us to query across other global databases such as the WOVOdat database of monitoring data and the Smithsonian Institution's Global Volcanism Program (GVP) database of eruptive histories and volcano information. The EFIS database is in the early stages of development and population; thus, this contribution also serves as a request for feedback from the community.

  12. 1600 AD Huaynaputina Eruption (Peru, Abrupt Cooling, and Epidemics in China and Korea

    Directory of Open Access Journals (Sweden)

    Jie Fei

    2016-01-01

    Full Text Available The 1600 AD Huaynaputina eruption in Peru was one of the largest volcanic eruptions in history over the past 2000 years. This study operated on the hypothesis that this event dramatically affected the weather and environment in China and the Korean Peninsula. Over the course of this research the Chinese and Korean historical literatures as well as dendrochronology records were examined. The historical evidence points to the conclusion that the eruption was followed by an abrupt cooling period and epidemic outbreaks in 1601 AD within both China and the Korean Peninsula. These records manifested themselves in unseasonably cold weather resulting in severe killing frosts in northern China in the summer and autumn of 1601 AD. In southern China (Zhejiang and Anhui Provinces and Shanghai Municipality, July was abnormally cold with snow, with an autumn that saw anomalously hot weather. In addition, there was unseasonable snowfall that autumn within Yunnan Province. Widespread disease outbreaks occurred in August, September, and October in northern and southern China. In Korea, the spring and early summer of 1601 AD were unusually cold, and conditions led to further widespread epidemics occurring in August.

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

    Science.gov (United States)

    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.

  14. Quiescent Prominences in the Era of ALMA. II. Kinetic Temperature Diagnostics

    Science.gov (United States)

    Gunár, Stanislav; Heinzel, Petr; Anzer, Ulrich; Mackay, Duncan H.

    2018-01-01

    We provide the theoretical background for diagnostics of the thermal properties of solar prominences observed by the Atacama Large Millimeter/submillimeter Array (ALMA). To do this, we employ the 3D Whole-Prominence Fine Structure (WPFS) model that produces synthetic ALMA-like observations of a complex simulated prominence. We use synthetic observations derived at two different submillimeter/millimeter (SMM) wavelengths—one at a wavelength at which the simulated prominence is completely optically thin and another at a wavelength at which a significant portion of the simulated prominence is optically thick—as if these were the actual ALMA observations. This allows us to develop a technique for an analysis of the prominence plasma thermal properties from such a pair of simultaneous high-resolution ALMA observations. The 3D WPFS model also provides detailed information about the distribution of the kinetic temperature and the optical thickness along any line of sight. We can thus assess whether the measure of the kinetic temperature derived from observations accurately represents the actual kinetic temperature properties of the observed plasma. We demonstrate here that in a given pixel the optical thickness at the wavelength at which the prominence plasma is optically thick needs to be above unity or even larger to achieve a sufficient accuracy of the derived information about the kinetic temperature of the analyzed plasma. Information about the optical thickness cannot be directly discerned from observations at the SMM wavelengths alone. However, we show that a criterion that can identify those pixels in which the derived kinetic temperature values correspond well to the actual thermal properties in which the observed prominence can be established.

  15. Warning signals for eruptive events in spreading fires.

    Science.gov (United States)

    Fox, Jerome M; Whitesides, George M

    2015-02-24

    Spreading fires are noisy (and potentially chaotic) systems in which transitions in dynamics are notoriously difficult to predict. As flames move through spatially heterogeneous environments, sudden shifts in temperature, wind, or topography can generate combustion instabilities, or trigger self-stabilizing feedback loops, that dramatically amplify the intensities and rates with which fires propagate. Such transitions are rarely captured by predictive models of fire behavior and, thus, complicate efforts in fire suppression. This paper describes a simple, remarkably instructive physical model for examining the eruption of small flames into intense, rapidly moving flames stabilized by feedback between wind and fire (i.e., "wind-fire coupling"-a mechanism of feedback particularly relevant to forest fires), and it presents evidence that characteristic patterns in the dynamics of spreading flames indicate when such transitions are likely to occur. In this model system, flames propagate along strips of nitrocellulose with one of two possible modes of propagation: a slow, structured mode, and a fast, unstructured mode sustained by wind-fire coupling. Experimental examination of patterns in dynamics that emerge near bifurcation points suggests that symptoms of critical slowing down (i.e., the slowed recovery of the system from perturbations as it approaches tipping points) warn of impending transitions to the unstructured mode. Findings suggest that slowing responses of spreading flames to sudden changes in environment (e.g., wind, terrain, temperature) may anticipate the onset of intense, feedback-stabilized modes of propagation (e.g., "blowup fires" in forests).

  16. Management of Large Erupting Complex Odontoma in Maxilla

    Directory of Open Access Journals (Sweden)

    Colm Murphy

    2014-01-01

    Full Text Available We present the unusual case of a large complex odontoma erupting in the maxilla. Odontomas are benign developmental tumours of odontogenic origin. They are characterized by slow growth and nonaggressive behaviour. Complex odontomas, which erupt, are rare. They are usually asymptomatic and are identified on routine radiograph but may present with erosion into the oral cavity with subsequent cellulitis and facial asymmetry. This present paper describes the presentation and management of an erupting complex odontoma, occupying the maxillary sinus with extension to the infraorbital rim. We also discuss various surgical approaches used to access this anatomic area.

  17. Settlement Relocation Modeling: Reacting to Merapi’s Eruption Incident

    Science.gov (United States)

    Pramitasari, A.; Buchori, I.

    2018-02-01

    Merapi eruption has made severe damages in Central Java Province. Klaten was one of the most affected area, specifically in Balerante Village. This research is made to comprehend GIS model on finding alternative locations for impacted settlement in hazardous zones of eruption. The principal objective of the research study is to identify and analyze physical condition, community characteristics, and local government regulation related to settlements relocation plan for impacted area of eruption. The output is location map which classified into four categories, i.e. not available, available with low accessibility, available with medium accessibility, and available with high accessibility.

  18. Eruptive history of Mammoth Mountain and its mafic periphery, California

    Science.gov (United States)

    Hildreth, Wes; Fierstein, Judy

    2016-07-13

    This report and accompanying geologic map portray the eruptive history of Mammoth Mountain and a surrounding array of contemporaneous volcanic units that erupted in its near periphery. The moderately alkaline Mammoth eruptive suite, basaltic to rhyodacitic, represents a discrete new magmatic system, less than 250,000 years old, that followed decline of the subalkaline rhyolitic system active beneath adjacent Long Valley Caldera since 2.2 Ma (Hildreth, 2004). The scattered vent array of the Mammoth system, 10 by 20 km wide, is unrelated to the rangefront fault zone, and its broad nonlinear footprint ignores both Long Valley Caldera and the younger Mono-Inyo rangefront vent alignment.

  19. Magma transport and storage at Mt. Etna (Italy): A review of geodetic and petrological data for the 2002-03, 2004 and 2006 eruptions

    Science.gov (United States)

    Palano, Mimmo; Viccaro, Marco; Zuccarello, Francesco; Gresta, Stefano

    2017-11-01

    A detailed reconstruction of magma movements within the plumbing system of Mt. Etna volcano has been made by reviewing the eruptions occurring during the October 2002-December 2006 period. The availability of continuous GPS data allowed detecting at least ten different ground deformation stages, highlighting deflationary and inflationary episodes as well as the occurrence of a shallow dike intrusion. These data have been coupled with the available petrological datasets including major/trace elements and Sr-Nd-Pb isotope compositions for the volcanic rocks erupted in the 2002-2006 period. We identified two main magmatic reservoirs located at different depths along the plumbing system of the volcano. The former is located at a depth of 7 km bsl and fed the 2001 and 2002-03 eruptions, while the latter, located from 3.5 to 5.5 km bsl, fed the 2004-05 and 2006 eruptions. Petrological characteristics of emitted products have been correlated with the inflation vs. deflation cycles related to the identified sources, providing evidence for changes through time of the evolutionary degree of the erupted magmas along with variations in their geochemical feature. Finally, we suggest that a modification of the deep plumbing system of the volcano might have occurred during the 2002-03 eruption, as a consequence of the major seaward motion of the eastern flank of the volcano.

  20. Prominence Bubbles and Plumes: Thermo-magnetic Buoyancy in Coronal Cavity Systems

    Science.gov (United States)

    Berger, Thomas; Hurlburt, N.

    2009-05-01

    The Hinode/Solar Optical Telescope continues to produce high spatial and temporal resolution images of solar prominences in both the Ca II 396.8 nm H-line and the H-alpha 656.3 nm line. Time series of these images show that many quiescent prominences produce large scale (50 Mm) dark "bubbles" that "inflate" into, and sometimes burst through, the prominence material. In addition, small-scale (2--5 Mm) dark plumes are seen rising into many quiescent prominences. We show typical examples of both phenomena and argue that they originate from the same mechanism: concentrated and heated magnetic flux that rises due to thermal and magnetic buoyancy to equilibrium heights in the prominence/coronal-cavity system. More generally, these bubbles and upflows offer a source of both magnetic flux and mass to the overlying coronal cavity, supporting B.C. Low's theory of CME initiation via steadily increasing magnetic buoyancy breaking through the overlying helmut streamer tension forces. Quiescent prominences are thus seen as the lowermost parts of the larger coronal cavity system, revealing through thermal effects both the cooled downflowing "drainage" from the cavity and the heated upflowing magnetic "plasmoids" supplying the cavity. We compare SOT movies to new 3D compressible MHD simulations that reproduce the dark turbulent plume dynamics to establish the magnetic and thermal character of these buoyancy-driven flows into the corona.

  1. The Fate of Cool Material in the Hot Corona: Solar Prominences and Coronal Rain

    Science.gov (United States)

    Liu, Wei; Antolin, Patrick; Sun, Xudong; Vial, Jean-Claude; Berger, Thomas

    2017-08-01

    As an important chain of the chromosphere-corona mass cycle, some of the million-degree hot coronal mass undergoes a radiative cooling instability and condenses into material at chromospheric or transition-region temperatures in two distinct forms - prominences and coronal rain (some of which eventually falls back to the chromosphere). A quiescent prominence usually consists of numerous long-lasting, filamentary downflow threads, while coronal rain consists of transient mass blobs falling at comparably higher speeds along well-defined paths. It remains puzzling why such material of similar temperatures exhibit contrasting morphologies and behaviors. We report recent SDO/AIA and IRIS observations that suggest different magnetic environments being responsible for such distinctions. Specifically, in a hybrid prominence-coronal rain complex structure, we found that the prominence material is formed and resides near magnetic null points that favor the radiative cooling process and provide possibly a high plasma-beta environment suitable for the existence of meandering prominence threads. As the cool material descends, it turns into coronal rain tied onto low-lying coronal loops in a likely low-beta environment. Such structures resemble to certain extent the so-called coronal spiders or cloud prominences, but the observations reported here provide critical new insights. We will discuss the broad physical implications of these observations for fundamental questions, such as coronal heating and beyond (e.g., in astrophysical and/or laboratory plasma environments).

  2. Prominence vs. aboutness in sequencing: a functional distinction within the left inferior frontal gyrus.

    Science.gov (United States)

    Bornkessel-Schlesewsky, Ina; Grewe, Tanja; Schlesewsky, Matthias

    2012-02-01

    Prior research on the neural bases of syntactic comprehension suggests that activation in the left inferior frontal gyrus (lIFG) correlates with the processing of word order variations. However, there are inconsistencies with respect to the specific subregion within the IFG that is implicated by these findings: the pars opercularis or the pars triangularis. Here, we examined the hypothesis that the dissociation between pars opercularis and pars triangularis activation may reflect functional differences between clause-medial and clause-initial word order permutations, respectively. To this end, we directly compared clause-medial and clause-initial object-before-subject orders in German in a within-participants, event-related fMRI design. Our results showed increased activation for object-initial sentences in a bilateral network of frontal, temporal and subcortical regions. Within the lIFG, posterior and inferior subregions showed only a main effect of word order, whereas more anterior and superior subregions showed effects of word order and sentence type, with higher activation for sentences with an argument in the clause-initial position. These findings are interpreted as evidence for a functional gradation of sequence processing within the left IFG: posterior subportions correlate with argument prominence-based (local) aspects of sequencing, while anterior subportions correlate with aboutness-based aspects of sequencing, which are crucial in linking the current sentence to the wider discourse. This proposal appears compatible with more general hypotheses about information processing gradients in prefrontal cortex (Koechlin & Summerfield, 2007). Copyright © 2010 Elsevier Inc. All rights reserved.

  3. Floating sandstones off El Hierro (Canary Islands, Spain): the peculiar case of the October 2011 eruption

    Science.gov (United States)

    Troll, V. R.; Klügel, A.; Longpré, M.-A.; Burchardt, S.; Deegan, F. M.; Carracedo, J. C.; Wiesmaier, S.; Kueppers, U.; Dahren, B.; Blythe, L. S.; Hansteen, T.; Freda, C.; Budd, D. A.; Jolis, E. M.; Jonsson, E.; Meade, F.; Berg, S.; Mancini, L.; Polacci, M.

    2011-12-01

    The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption.

  4. Tsunamis generated by eruptions from mount st. Augustine volcano, alaska.

    Science.gov (United States)

    Kienle, J; Kowalik, Z; Murty, T S

    1987-06-12

    During an eruption of the Alaskan volcano Mount St. Augustine in the spring of 1986, there was concern about the possibility that a tsunami might be generated by the collapse of a portion of the volcano into the shallow water of Cook Inlet. A similar edifice collapse of the volcano and ensuing sea wave occurred during an eruption in 1883. Other sea waves resulting in great loss of life and property have been generated by the eruption of coastal volcanos around the world. Although Mount St. Augustine remained intact during this eruptive cycle, a possible recurrence of the 1883 events spurred a numerical simulation of the 1883 sea wave. This simulation, which yielded a forecast of potential wave heights and travel times, was based on a method that could be applied generally to other coastal volcanos.

  5. N