The 2002–03 Etna explosive activity: Tephra dispersal and features of the deposits

[1] The onset of Mt. Etna's 2002–03 eruption was marked by intense explosive activity beginning on 27 October 2002 and persisting until 30 December. This phase of activity produced abundant ash emission that impacted the local economy and air traffic. Thereafter, explosive activity declined with the eruption ceasing on 28 January 2003. In this paper, we present field data collected during the eruption and use these to obtain input data for tephra dispersal model. This was applied, after validation, to extrapolate the total distribution of the deposits emplaced during the explosive activity. Detailed sampling of fallout deposits was completed on 27, 28, 31 October and 4 November. This enabled construction of isomass maps and calculation of the erupted mass. Grain-size analysis of all collected samples was used to reconstruct the total grain-size distribution which displays a peak at 0.5 Φ. Column height was estimated at 3.3–7 km by combining barometrical altimeter data during over-flights with the analysis of images and videos. This was used to estimate a total erupted mass of 4.4 ± 0.6 × 1010 kg. Simulations showed that the deposit was significantly affected by variations in wind direction and mass eruption rate, with deposits being dispersed mainly on the E sector of the volcano due to a dominant easterly wind. Our study underlines that basaltic volcanoes, such as Etna, can produce huge amounts of ash, as well as lava, and that an improvement in the knowledge of dispersal processes during prolonged explosive activity is required to better mitigate the associated hazards.

[1]  Augusto Neri,et al.  The VOL-CALPUFF model for atmospheric ash dispersal: 1. Approach and physical formulation , 2008 .

[2]  D. Andronico,et al.  Alert system to mitigate tephra fallout hazards at Mt. Etna Volcano, Italy , 2007 .

[3]  Simona Scollo,et al.  Tephra fallout of 2001 Etna flank eruption: Analysis of the deposit and plume dispersion , 2007 .

[4]  M. Pompilio,et al.  Petrologic evidence of a complex plumbing system feeding the July–August 2001 eruption of Mt. Etna, Sicily, Italy , 2007 .

[5]  D. Andronico,et al.  Coupled textural and compositional characterization of basaltic scoria: Insights into the transition from Strombolian to fire fountain activity at Mount Etna, Italy , 2006 .

[6]  Arnau Folch,et al.  A three-dimensional Eulerian model for transport and deposition of volcanic ashes , 2006 .

[7]  L. Vezzoli,et al.  Explosive eruption of a picrite: The 3930 BP subplinian eruption of Etna volcano (Italy) , 2005 .

[8]  Antonella Longo,et al.  A computer model for volcanic ash fallout and assessment of subsequent hazard , 2005, Comput. Geosci..

[9]  Costanza Bonadonna,et al.  Modeling tephra sedimentation from a Ruapehu weak plume eruption , 2005 .

[10]  R. A. Corsaro,et al.  Dynamics of 2004–2005 Mt. Etna effusive eruption as inferred from petrologic monitoring , 2005 .

[11]  Paola Del Carlo,et al.  Types of eruptions of Etna volcano AD 1670–2003: implications for short-term eruptive behaviour , 2005 .

[12]  Arlene Laing,et al.  Probabilistic modeling of tephra dispersal: Hazard assessment of a multiphase rhyolitic eruption at Tarawera, New Zealand , 2005 .

[13]  G. Macedonio,et al.  A model for the numerical simulation of tephra fall deposits , 2005 .

[14]  Daniele Andronico,et al.  Effusive Activity at Mount Etna Volcano (Italy) During the 20th Century: A Contribution to Volcanic Hazard Assessment , 2005 .

[15]  Costanza Bonadonna,et al.  Total grain-size distribution and volume of tephra-fall deposits , 2005 .

[16]  Warwick D. Smith,et al.  A Monte Carlo methodology for modelling ashfall hazards , 2004 .

[17]  E. Privitera,et al.  Insight into Mt. Etna (Italy) kinematics during the 2002–2003 eruption as inferred from seismic stress and strain tensors , 2004 .

[18]  S. Barnard.  Results of a reconnaissance trip to Mt. Etna, Italy: , 2004 .

[19]  E. Parfitt,et al.  A discussion of the mechanisms of explosive basaltic eruptions , 2004 .

[20]  G. M. Crisci,et al.  The simulation model SCIARA: the 1991 and 2001 lava flows at Mount Etna , 2004 .

[21]  Harry Pinkerton,et al.  Birth, growth and morphologic evolution of the 'Laghetto' cinder cone during the 2001 Etna eruption , 2004 .

[22]  K. Kyriakopoulos,et al.  Phreatomagmatic ash from the ongoing eruption of Etna reaching the Greek island of Cefalonia , 2003 .

[23]  Costanza Bonadonna,et al.  Sedimentation from strong volcanic plumes , 2003 .

[24]  Daniele Andronico,et al.  Relationship between tremor and volcanic activity during the Southeast Crater eruption on Mount Etna in early 2000 , 2003 .

[25]  J. Taddeucci,et al.  Monitoring the ashes from the 2002-2003 flank eruption of Mount Etna (Italy) , 2003 .

[26]  Roberto Santacroce,et al.  Assessing pyroclastic fall hazard through field data and numerical simulations: Example from Vesuvius , 2003 .

[27]  B. Voight,et al.  Episodes of cyclic Vulcanian explosive activity with fountain collapse at Soufrière Hills Volcano, Montserrat , 2002, Geological Society, London, Memoirs.

[28]  C. Bonadonna,et al.  Numerical modelling of tephra fallout associated with dome collapses and Vulcanian explosions: application to hazard assessment on Montserrat , 2002, Geological Society, London, Memoirs.

[29]  Sonia Calvari,et al.  Multidisciplinary approach yields insight into Mt. Etna eruption , 2001 .

[30]  R. Showstack.  Panel urges measures to minimize effects of future abrupt climate changes , 2001 .

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

[32]  F. Mazzarini,et al.  Flank Cones at Mount Etna Volcano: Do they have a power-law distribution? , 2001 .

[33]  Andrew W. Woods,et al.  Explosive Volcanic Eruptions , 2001 .

[34]  L. Vezzoli,et al.  Stratigraphic constraints for explosive activity in the past 100 ka at Etna Volcano, Italy , 2000 .

[35]  Mauro Coltelli,et al.  Discovery of a Plinian basaltic eruption of Roman age at Etna volcano, Italy , 1998 .

[36]  S. Calvari,et al.  Formation of lava tubes and extensive flow field during the 1991–1993 eruption of Mount Etna , 1998 .

[37]  E. Parfitt.  A study of clast size distribution, ash deposition and fragmentation in a Hawaiian-style volcanic eruption , 1998 .

[38]  A. Roshko,et al.  Vortical structure in the wake of a transverse jet , 1994, Journal of Fluid Mechanics.

[39]  Jp Davis,et al.  Bifurcation of volcanic plumes in a crosswind , 1994 .

[40]  T. Casadevall,et al.  Volcanic ash and aviation safety; proceedings of the First international symposium on Volcanic ash and aviation safety , 1994 .

[41]  A. Woods.  A model of the plumes above basaltic fissure eruptions , 1993 .

[42]  Maria Luisa Carapezza,et al.  The control of lava flow during the 1991 1992 eruption of Mt. Etna , 1993 .

[43]  M. Nathenson,et al.  Another look at the calculation of fallout tephra volumes , 1992 .

[44]  Atsuyuki Okabe,et al.  Spatial Tessellations: Concepts and Applications of Voronoi Diagrams , 1992, Wiley Series in Probability and Mathematical Statistics.

[45]  D. Pyle.  The thickness, volume and grainsize of tephra fall deposits , 1989 .

[46]  M. Pareschi,et al.  A Numerical Simulation of the Plinian Fall Phase of 79 A.D. Eruption of Vesuvius , 1988 .

[47]  M. T. Pareschi,et al.  A numerical model for simulation of tephra transport and deposition: Applications to May 18, 1980, Mount St. Helens eruption , 1988 .

[48]  L. Wilson,et al.  Explosive volcanic eruptions - VI. Ejecta dispersal in plinian eruptions: the control of eruption conditions and atmospheric properties , 1987 .

[49]  S. Self,et al.  Basaltic fissure eruptions, plume heights, and atmospheric aerosols , 1986 .

[50]  Lionel Wilson,et al.  Tarawera 1886, New Zealand — A basaltic plinian fissure eruption , 1984 .

[51]  J. G. Moore,et al.  Man against volcano : the eruption on Heimaey, Vestmannaeyjar, Iceland , 1983 .

[52]  H. Arastoopour,et al.  Particle—particle interaction force in a dilute gas—solid system , 1982 .

[53]  J. Murray,et al.  An analysis of hazard from Mount Etna volcano , 1979, Journal of the Geological Society.

[54]  Lionel Wilson,et al.  Mechanisms and dynamics of strombolian activity , 1976, Journal of the Geological Society.

[55]  S. Self,et al.  The 1973 Heimaey Strombolian Scoria deposit, Iceland , 1974, Geological Magazine.

[56]  Geoffrey Ingram Taylor,et al.  Turbulent gravitational convection from maintained and instantaneous sources , 1956, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[57]  D. Inman,et al.  Measures for describing the size distribution of sediments , 1952 .