Bulletin of Volcanology

, Volume 66, Issue 5, pp 443–456 | Cite as

Doppler radar sounding of volcanic eruption dynamics at Mount Etna

  • G. Dubosclard
  • F. DonnadieuEmail author
  • P. Allard
  • R. Cordesses
  • C. Hervier
  • M. Coltelli
  • E. Privitera
  • J. Kornprobst
Research Article


Besides their common use in atmospheric studies, Doppler radars are promising tools for the active remote sensing of volcanic eruptions but were little applied to this field. We present the observations made with a mid-power UHF Doppler radar (Voldorad) during a 7-h Strombolian eruption at the SE crater of Mount Etna on 11–12 October 1998. Main characteristics of radar echoes are retrieved from analysis of Doppler spectra recorded in the two range gates on either side of the jet axis. From the geometry of the sounding, the contribution of uprising and falling ejecta to each Doppler spectrum can be discriminated. The temporal evolution of total power backscattered by uprising targets is quite similar to the temporal evolution of the volcanic tremor and closely reproduces the overall evolution of the eruption before, during and after its paroxysm. Moreover, during the sharp decrease of eruptive activity following the paroxysm, detailed analysis of video (from camera recording), radar and seismic measurements reveals that radar and video signals start to decrease simultaneously, approximately 2.5 min after the tremor decline. This delay is interpreted as the ascent time through a magma conduit of large gas slugs from a shallow source roughly estimated at about 500 m beneath the SE crater. Detailed analysis of eruptive processes has been also made with Voldorad operating in a high sampling rate mode. Signature of individual outburst is clearly identified on the half part of Doppler spectra corresponding to rising ejecta: temporal variations of the backscattered power exhibit quasi periodic undulations, whereas the maximum velocity measured on each spectrum displays a sharp peak at the onset of each outburst followed by a slow decay with time. Periodicity of power variations (between 3.8 and 5.5 s) is in agreement with the occurrence of explosions visually observed at the SE vent. Maximum vertical velocities of over 160 m s−1 were measured during the paraoxysmal stage and the renewed activity. Finally, by using a simplified model simulating the radar echoes characteristics, we show that when Voldorad is operating in high sampling rate mode, the power and maximum velocity variations are directly related to the difference in size and velocity of particles crossing the antenna beam.


Explosive eruption Volcanic jet Doppler radar Particle velocity Gas velocity Doppler spectrum Volcanic tremor 



We thank S. Vergniolle and an anonymous referee for their thoughtful comments, and A. Woods for handling the paper. This work was supported by the European Community (contract ENV4-CT96–0288), CNRS (INSU-PNRN) and CRV (Coordination de la Recherche Volcanologique). Facilities for radar soundings at Mt. Etna were kindly provided by Istituto Internazionale di Vulcanologia (Catania) and Parco dell’Etna (Nicolosi). F.D. was supported by the French Société de Secours des Amis des Sciences. We gratefully acknowledge helpful contributions from T. Caltabiano, O. Coutant and V. Pinel.


  1. Blackburn EA, Wilson L, Sparks RS J (1976) Mechanisms and dynamics of Strombolian activity. J Geol Soc Lond 132:429–440Google Scholar
  2. Chouet B, Hamisevicz N, Mc Getchin TR (1974) Photoballistics of volcanic jet activity at Stromboli, Italy. J Geophys Res 79: 4961–4976Google Scholar
  3. Chouet B, Saccorotti G, Dawson PB, Martini M, Scarpa R, De Luca G, Milana G, Cattaneo M (1999) Broadband measurements of the sources of explosions at Stromboli Volcano, Italy. Geophys Res Lett 26:1937–1940CrossRefGoogle Scholar
  4. Chow CY (1979) An introduction to computational fluid mechanics. Wiley, New YorkGoogle Scholar
  5. Cosentino M, Lombardo G, Privitera E (1989) A model for internal dynamical processes on Mt. Etna. Geophys J R Astron Soc 97(3):367–379Google Scholar
  6. Della Schiava M (1995) Effetto del gas sull’origine del campo d’onda sismico registrato a Stromboli. Tesi di Laurea, Dip. di Scienze della Terra, Università di FirenzeGoogle Scholar
  7. Dubosclard G, Cordesses R, Allard P, Hervier C, Coltelli M, Kornprobst J (1999) First testing of a volcano Doppler radar (Voldorad) at Mount Etna, Italy. Geophys Res Lett 26:3389–3392CrossRefGoogle Scholar
  8. Ereditato D, Luongo G (1994) Volcanic tremor wave field during quiescent and eruptive activity at Mt. Etna (Sicily) J Volcanol Geotherm Res 61:239–251Google Scholar
  9. Falsaperla S, Privitera E, Spampinato S, Cardaci C (1994) Seismic activity and volcanic tremor related to the December 14, 1991 Mt. Etna eruption. Acta Vulcanol 4:63–73Google Scholar
  10. Gresta S, Montalto A, Patane G (1991) Volcanic tremor at Mount Etna (January 1984-March 1985): its relationship to the eruptive activity and modelling of the summit feeding system. Bull Volcanol 53:309–320Google Scholar
  11. GVN (1998) Global Volcanism Network, Bulletin of the Global Volcanism Program of the Smithsonian Institution, Washington DC, 23(12):10–12Google Scholar
  12. Hort M, Seyfried R (1998) Volcanic eruption velocities measured with a micro radar. Geophys Res Lett 25:113–116Google Scholar
  13. INGV scientific staff (2001) Multidisciplinary approach yields insight into Mt. Etna eruption. EOS Trans Am Geophys Union 82 (52):653–656Google Scholar
  14. Jaupart C, Vergniolle S (1988) Laboratory models of Hawaiian and Strombolian eruptions. Nature 331:58–60CrossRefGoogle Scholar
  15. La Delfa S, Patanè G, Clocchiatti R, Joron JL, Tanguy JL (2001) Activity of Mount Etna preceding the February 1999 fissure eruption: inferred mechanism from seismological and geochemical data. J Volcanol Geotherm Res 105:121–139CrossRefGoogle Scholar
  16. Laigle M, Hirn A (1999) Explosion-seismic tomography of a magmatic body beneath Mount Etna; volatile discharge and tectonic control of volcanism. Geophys Res Lett 26:2665–2668Google Scholar
  17. Laigle M, Hirn A, Sapin M, Lepine J-C, Diaz J, Gallart J, Nicolich R (2000) Mount Etna dense array local earthquake P and S tomography and implications for volcanic plumbing. J Geophys Res 105:21633–21646Google Scholar
  18. Mauk, JM (1983) Utilization of seismically recorded infrasonic-acoustic signals to monitor volcanic explosions: the El Chichon sequence 1982- a case study. J Geophys Res 88:10385–10401Google Scholar
  19. McGetchin TR, Settle M, Chouet BA (1974) Cinder cone growth modeled after Northeast crater, Mount Etna, Sicily. J Geophys Res 79:3257–3272Google Scholar
  20. Montalto A, Distefano G, Patane G (1992) Seismic patterns preceding and accompanying the January 15, 1990 eruptive paroxysm on Mt. Etna (Italy). J Volcanol Geotherm Res 51:133–143CrossRefGoogle Scholar
  21. Montalto A, Longo V, Patane G (1995) Echo-resonance and hydraulic perturbations in magma cavities: application to the volcanic tremor of Etna (Italy) in relation to its eruptive activity. Bull Volcanol 57:219–228CrossRefGoogle Scholar
  22. Neuberg J, Luckett R, Ripepe M, Braun T (1994) Highlights from a seismic broadband array on Stromboli volcano. Geophys Res Lett 21(9):749–752Google Scholar
  23. Ripepe M (1996) Evidence for gas influence on volcanic seismic signals recorded at Stromboli. J Volcanol Geotherm Res 70:221–233Google Scholar
  24. Ripepe M, Ciliberto S, Della Schiava M (2001) Time constraints for modeling source dynamics of volcanic explosions at Stromboli. J Geophys Res 106:8713–8727Google Scholar
  25. Ripepe M, Coltelli M, Privitera E, Gresta S, Moretti M, Piccinini D (2001) Seismic and infrasonic evidences for an impulsive source of the shallow volcanic tremor at Mt. Etna, Italy. Geophys Res Lett 28(6):1071–1074Google Scholar
  26. Ripepe M, Gordeev E (1999) Gas bubble dynamics model for shallow volcanic tremor at Stromboli. J Geophys Res 104:10639–110654CrossRefGoogle Scholar
  27. Ripepe M, Poggi P, Braun T, Gordeev E (1996) Infrasonic waves and volcanic tremor at Stromboli. Geophys Res Lett 23 (2):381–384Google Scholar
  28. Ripepe M, Rosi M, Saccorotti G (1993) Image processing of explosive activity at Stromboli. J Volcanol Geotherm Res 54:335–351CrossRefGoogle Scholar
  29. Sauvageot H (1992) Radar meteorology, Artech House, Boston, pp 1–366Google Scholar
  30. Schick R, Riuscetti M (1973) An analysis of volcanic tremors at south Italian volcanoes. Z Geophys 39:247–262Google Scholar
  31. Seyfried R, Hort M (1999) Continuous monitoring of volcanic eruption dynamics: a review of various techniques and new results from a frequency-modulated radar Doppler system. Bull Volcanol 60:627–639CrossRefGoogle Scholar
  32. Sparks RSJ, Wilson L (1982) Explosive volcanic eruptions V. Observations of plume dynamics during the 1979 Soufriere eruption, St Vincent. Geophys J R Astron Soc 69:551–570Google Scholar
  33. Steinberg GS, Babenko JI (1978) Gas velocity and density determination by filming gas discharges. J Volcanol Geotherm Res 3:89–98CrossRefGoogle Scholar
  34. Vergniolle S (1998) Modeling two-phase flow in a volcano. 13th Aust Fluid Mech Conf, Monash University, Melbourne, Australia, pp 647–650Google Scholar
  35. Vergniolle S (2001) Listening to Stromboli volcano as a tool into its volcanic conduit. EOS Trans, AGU fall meeting, pp 1399–1400Google Scholar
  36. Vergniolle S, Brandeis G (1996) Strombolian explosions, part 1: a large bubble breaking at the surface of a lava column as a source of sound. J Geophys Res 101:20433–20447Google Scholar
  37. Vergniolle S, Brandeis G, Mareschal JC (1996) Strombolian explosions, part 2: Eruption dynamics determined from acoustic measurements. J Geophys Res 101:20449–20466Google Scholar
  38. Vergniolle S, Jaupart C (1986) Separated two-phase flow and basaltic eruptions. J Geophys Res 91:12842–12860Google Scholar
  39. Vergniolle S, Mangan M (2000) Hawaiian and Strombolian eruptions. In: Sigurdsson H et al (eds) Encyclopedia of volcanoes. pp 447–461Google Scholar
  40. Wallis GB (1969) One-dimensional two-phase flows. McGraw-Hill, New York, pp 1–408Google Scholar
  41. Weill A, Brandeis G, Vergniolle S, Baudin F, Bilbille J, Fèvre JF, Piron B, Hill X (1992) Acoustic sounder measurements of the vertical velocity of volcanic jets at Stromboli volcano. Geophys Res Lett 19:2357–2360Google Scholar

Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  • G. Dubosclard
    • 1
    • 2
  • F. Donnadieu
    • 1
    • 5
    Email author
  • P. Allard
    • 3
  • R. Cordesses
    • 1
  • C. Hervier
    • 1
  • M. Coltelli
    • 4
  • E. Privitera
    • 4
  • J. Kornprobst
    • 1
    • 5
  1. 1.OPGCUniversité Blaise PascalClermont-FerrandFrance
  2. 2.Laboratoire de Météorologie PhysiqueUniversité Blaise Pascal - CNRSClermont-FerrandFrance
  3. 3.LSCECEA-CNRSGif/YvetteFrance
  4. 4.Istituto Nazionale di Geofisica e VulcanologiaSezione di CataniaItaly
  5. 5.Laboratoire Magmas & VolcansUniversité Blaise Pascal - CNRSClermont-FerrandFrance

Personalised recommendations