Furthering the investigation of eruption styles through quantitative shape analyses of volcanic ash particles

Abstract Volcanic ash morphology has been quantitatively investigated for various aims such as studying the settling velocity of ash for modelling purposes and understanding the fragmentation processes at the origin of explosive eruptions. In an attempt to investigate the usefulness of ash morphometry for monitoring purposes, we analyzed the shape of volcanic ash particles through a combination of (1) traditional shape descriptors such as solidity, convexity, axial ratio and form factor and (2) fractal analysis using the Euclidean Distance transform (EDT) method. We compare ash samples from the hydrothermal eruptions of Iwodake (Japan) in 2013, Tangkuban Perahu (Indonesia) in 2013 and Marapi (Sumatra, Indonesia) in 2015, the dome explosions of Merapi (Java, Indonesia) in 2013, the Vulcanian eruptions of Merapi in 2010 and Tavurvur (Rabaul, Papaua New Guinea) in 2014, and the Plinian eruption of Kelud (Indonesia) in 2014. Particle size and shape measurements were acquired from a Particle Size Analyzer with a microscope camera attached to the instrument. Clear differences between dense/blocky particles from hydrothermal or dome explosions and vesicular particles produced by the fragmentation of gas-bearing molten magma are well highlighted by conventional shape descriptors and the fractal method. In addition, subtle differences between dense/blocky particles produced by hydrothermal explosions, dome explosions, or quench granulation during phreatomagmatic eruptions can be evidenced with the fractal method. The combination of shape descriptors and fractal analysis is therefore potentially able to distinguish between juvenile and non-juvenile magma, which is of importance for eruption monitoring.

[1]  A. Kent,et al.  Identification and evolution of the juvenile component in 2004-2005 Mount St. Helens ash , 2008 .

[2]  S. Gíslason,et al.  The role of bubbles in generating fine ash during hydromagmatic eruptions , 2015 .

[3]  B. Mandelbrot How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension , 1967, Science.

[4]  T. Thordarson,et al.  Ash from the Eyjafjallajökull eruption (Iceland): Fragmentation processes and aerodynamic behavior , 2012 .

[5]  D. Bérubé,et al.  High precision boundary fractal analysis for shape characterization , 1999 .

[6]  G. Walker,et al.  Two Plinian-type eruptions in the Azores , 1971, Journal of the Geological Society.

[7]  Alison C Rust,et al.  Optimising shape analysis to quantify volcanic ash morphology , 2015 .

[8]  N. Geshi,et al.  Temporal variation in volcanic ash texture during a vulcanian eruption at the Sakurajima volcano, Japan , 2013 .

[9]  R. Wunderman Report on Merapi (Indonesia) , 2020, Bulletin of the Global Volcanism Network.

[10]  J. Taddeucci,et al.  Monitoring the explosive activity of the July–August 2001 eruption of Mt. Etna (Italy) by ash characterization , 2001 .

[11]  B. Zimanowski,et al.  Processes controlling the shape of ash particles: Results of statistical IPA , 2014 .

[12]  K. Németh Volcanic glass textures, shape characteristics and compositions of phreatomagmatic rock units from the Western Hungarian monogenetic volcanic fields and their implications for magma fragmentation , 2010 .

[13]  David J. Schneider,et al.  Merapi 2010 eruption—Chronology and extrusion rates monitored with satellite radar and used in eruption forecasting , 2013 .

[14]  R. Sparks,et al.  Causes and consequences of pressurisation in lava dome eruptions , 1997 .

[15]  Tohru Yamashita,et al.  Juvenile volcanic glass erupted before the appearance of the 1991 lava dome, Unzen volcano, Kyushu, Japan , 1999 .

[16]  R. Cioni,et al.  Fingerprinting ash deposits of small scale eruptions by their physical and textural features , 2008 .

[17]  Massimo Pompilio,et al.  Magma dynamics within a basaltic conduit revealed by textural and compositional features of erupted ash: the December 2015 Mt. Etna paroxysms , 2017, Scientific Reports.

[18]  William I. Rose,et al.  Hydrometeor-enhanced tephra sedimentation: Constraints from the 18 May 1980 eruption of Mount St. Helens , 2009 .

[19]  H. Sigurdsson,et al.  Use of fractal analysis for discrimination of particles from primary and reworked jökulhlaup deposits in SE Iceland , 2000 .

[20]  A. Bertagnini,et al.  A review on phreatic eruptions and their precursors , 1992 .

[21]  Takahiro Miwa,et al.  Characterization of the luminance and shape of ash particles at Sakurajima volcano, Japan, using CCD camera images , 2015, Bulletin of Volcanology.

[22]  Y. Yamanoi,et al.  Color measurements of volcanic ash deposits from three different styles of summit activity at Sakurajima volcano, Japan: Conduit processes recorded in color of volcanic ash , 2008 .

[23]  P. Alken,et al.  Swarm SCARF equatorial electric field inversion chain , 2013, Earth, Planets and Space.

[24]  Tom Simkin,et al.  Volcanoes of the World , 2011 .

[25]  Benjamin Bernard,et al.  Juvenile magma recognition and eruptive dynamics inferred from the analysis of ash time series: The 2015 reawakening of Cotopaxi volcano , 2016 .

[26]  K. Wohletz,et al.  Fragmentation Processes in Explosive Volcanic Eruptions , 1991 .

[27]  C. Bonadonna,et al.  Insights into the dynamics and evolution of the 2010 Eyjafjallajökull summit eruption (Iceland) provided by volcanic ash textures , 2014 .

[28]  R. Hoblitt,et al.  Magmatic precursors to the 18 May 1980 eruption of Mount St. Helens, USA , 2004 .

[29]  Pierfrancesco Dellino,et al.  Identifying magma–water interaction from the surface features of ash particles , 1999, Nature.

[30]  J. White,et al.  Pyroclast characteristics of a subaqueous to emergent Surtseyan eruption, Black Point volcano, California , 2013 .

[31]  Steven Carey,et al.  Quantitative discrimination of magma fragmentation and pyroclastic transport processes using the fractal spectrum technique , 2007 .

[32]  F. Costa,et al.  Mafic magma replenishment, unrest and eruption in a caldera setting: insights from the 2006 eruption of Rabaul (Papua New Guinea) , 2015, Special Publications.

[33]  G. Lube,et al.  Perils in distinguishing phreatic from phreatomagmatic ash; insights into the eruption mechanisms of the 6 August 2012 Mt. Tongariro eruption, New Zealand , 2014 .

[34]  P. Vonlanthen,et al.  Eifel maars: Quantitative shape characterization of juvenile ash particles (Eifel Volcanic Field, Germany) , 2015 .

[35]  M. Luppe Fractal dimension based on Minkowski-Bouligand method using exponential dilations , 2015 .

[36]  O. Melnik,et al.  Nonlinear dynamics of lava dome extrusion , 1999, Nature.

[37]  R. Wunderman Report on Kelut (Indonesia) , 2008 .

[38]  Kenneth H. Wohletz,et al.  Mechanisms of hydrovolcanic pyroclast formation: Grain-size, scanning electron microscopy, and experimental studies , 1983 .

[39]  Pierfrancesco Dellino,et al.  The fractal and multifractal dimension of volcanic ash particles contour: a test study on the utility and volcanological relevance , 2002 .

[40]  Grant Heiken,et al.  Morphology and Petrography of Volcanic Ashes , 1972 .

[41]  J. Pallister,et al.  Petrological insights into the storage conditions, and magmatic processes that yielded the centennial 2010 Merapi explosive eruption , 2013 .

[42]  Erkan Aydar,et al.  Quantitative scanning-electron microscope analysis of volcanic ash surfaces: Application to the 1982–1983 Galunggung eruption (Indonesia) , 2007 .

[43]  J. Pennec,et al.  Towards fast and routine analyses of volcanic ash morphometry for eruption surveillance applications , 2015 .

[44]  S. Carey,et al.  Using fractal analysis to quantitatively characterize the shapes of volcanic particles , 2002 .

[45]  William I. Rose,et al.  Quantitative shape measurements of distal volcanic ash , 2003 .

[46]  D. Fornari,et al.  Craters, calderas, and hyaloclastites on young Pacific seamounts , 1984 .

[47]  R. Büttner,et al.  Thermohydraulic explosions in phreatomagmatic eruptions as evidenced by the comparison between pyroclasts and products from Molten Fuel Coolant Interaction experiments , 2002 .

[48]  Pierfrancesco Dellino,et al.  Image processing analysis in reconstructing fragmentation and transportation mechanisms of pyroclastic deposits. The case of Monte Pilato-Rocche Rosse eruptions, Lipari (Aeolian islands, Italy) , 1996 .

[49]  J. Stimac,et al.  Variation of volatile concentration in a magma system of Satsuma-Iwojima volcano deduced from melt inclusion analyses , 2001 .

[50]  J. Taddeucci,et al.  SEM-based methods for the analysis of basaltic ash from weak explosive activity at Etna in 2006 and the 2007 eruptive crisis at Stromboli , 2012 .

[51]  S. Self,et al.  The volcanic explosivity index (VEI) an estimate of explosive magnitude for historical volcanism , 1982 .

[52]  L. Frazer,et al.  Constraining particle size‐dependent plume sedimentation from the 17 June 1996 eruption of Ruapehu Volcano, New Zealand, using geophysical inversions , 2014 .

[53]  T. Kaneko,et al.  Precursory activity and evolution of the 2011 eruption of Shinmoe-dake in Kirishima volcano—insights from ash samples , 2013, Earth, Planets and Space.

[54]  H. Harman Modern factor analysis , 1961 .

[55]  R. Sulpizio,et al.  A systematic investigation on the aerodynamics of ash particles , 2011 .

[56]  R. Büttner,et al.  Fragmentation of basaltic melt in the course of explosive volcanism , 1997 .

[57]  S. Hidayati,et al.  Emergence of Lava Dome from the Crater Lake of Kelud Volcano, East Java , 2009 .